* [PATCH] 2.5.44: lkcd (9/9): dump driver and build files
@ 2002-10-21 10:16 Matt D. Robinson
2002-10-21 21:21 ` Christoph Hellwig
0 siblings, 1 reply; 16+ messages in thread
From: Matt D. Robinson @ 2002-10-21 10:16 UTC (permalink / raw)
To: linux-kernel, yakker
This is the complete set of dump drivers for creating crash dumps
during panic/exception situations in the Linux kernel. It can be
built as a module or as a built-in with the kernel.
drivers/Makefile | 1
drivers/dump/Makefile | 30
drivers/dump/dump_base.c | 1860 +++++++++++++++++++++++++++++++++++++++++++
drivers/dump/dump_blockdev.c | 392 +++++++++
drivers/dump/dump_i386.c | 315 +++++++
include/asm-i386/dump.h | 94 ++
include/linux/dump.h | 438 ++++++++++
diff -Naur linux-2.5.44.orig/drivers/Makefile linux-2.5.44.lkcd/drivers/Makefile
--- linux-2.5.44.orig/drivers/Makefile Fri Oct 18 21:02:28 2002
+++ linux-2.5.44.lkcd/drivers/Makefile Sat Oct 19 12:39:15 2002
@@ -41,5 +41,6 @@
obj-$(CONFIG_BT) += bluetooth/
obj-$(CONFIG_HOTPLUG_PCI) += hotplug/
obj-$(CONFIG_ISDN_BOOL) += isdn/
+obj-$(CONFIG_CRASH_DUMP) += dump/
include $(TOPDIR)/Rules.make
diff -Naur linux-2.5.44.orig/drivers/dump/Makefile linux-2.5.44.lkcd/drivers/dump/Makefile
--- linux-2.5.44.orig/drivers/dump/Makefile Wed Dec 31 16:00:00 1969
+++ linux-2.5.44.lkcd/drivers/dump/Makefile Sat Oct 19 12:39:15 2002
@@ -0,0 +1,30 @@
+#
+# Makefile for the dump device drivers.
+#
+# 12 June 2000, Christoph Hellwig <schch@pe.tu-clausthal.de>
+# Rewritten by Matt D. Robinson (yakker@sourceforge.net) for
+# the dump directory.
+#
+export-objs := dump_base.o
+
+obj-$(CONFIG_CRASH_DUMP) += dump.o
+
+dump-y := dump_base.o
+obj-$(CONFIG_CRASH_DUMP_BLOCKDEV) += dump_blockdev.o
+obj-$(CONFIG_CRASH_DUMP_COMPRESS_RLE) += dump_rle.o
+obj-$(CONFIG_CRASH_DUMP_COMPRESS_GZIP) += dump_gzip.o
+dump-objs += $(dump-y)
+
+ifeq ($(ARCH),i386)
+dump-objs += dump_i386.o
+endif
+
+ifeq ($(ARCH),alpha)
+dump-objs += dump_alpha.o
+endif
+
+ifeq ($(ARCH),ia64)
+dump-objs += dump_ia64.o
+endif
+
+include $(TOPDIR)/Rules.make
diff -Naur linux-2.5.44.orig/drivers/dump/dump_base.c linux-2.5.44.lkcd/drivers/dump/dump_base.c
--- linux-2.5.44.orig/drivers/dump/dump_base.c Wed Dec 31 16:00:00 1969
+++ linux-2.5.44.lkcd/drivers/dump/dump_base.c Sat Oct 19 12:39:15 2002
@@ -0,0 +1,1860 @@
+/*
+ * Standard kernel functions for Linux crash dumps.
+ *
+ * Created by: Matt Robinson (yakker@sourceforge.net)
+ * Contributions from SGI, IBM, HP, MCL, and others.
+ *
+ * Copyright (C) 1999 - 2002 Silicon Graphics, Inc. All rights reserved.
+ * Copyright (C) 2000 - 2002 TurboLinux, Inc. All rights reserved.
+ * Copyright (C) 2001 - 2002 Matt D. Robinson. All rights reserved.
+ * Copyright (C) 2002 Free Software Foundation, Inc. All rights reserved.
+ *
+ * This code is released under version 2 of the GNU GPL.
+ */
+
+/*
+ * -----------------------------------------------------------------------
+ *
+ * DUMP HISTORY
+ *
+ * This dump code goes back to SGI's first attempts at dumping system
+ * memory on SGI systems running IRIX. A few developers at SGI needed
+ * a way to take this system dump and analyze it, and created 'icrash',
+ * or IRIX Crash. The mechanism (the dumps and 'icrash') were used
+ * by support people to generate crash reports when a system failure
+ * occurred. This was vital for large system configurations that
+ * couldn't apply patch after patch after fix just to hope that the
+ * problems would go away. So the system memory, along with the crash
+ * dump analyzer, allowed support people to quickly figure out what the
+ * problem was on the system with the crash dump.
+ *
+ * In comes Linux. SGI started moving towards the open source community,
+ * and upon doing so, SGI wanted to take its support utilities into Linux
+ * with the hopes that they would end up the in kernel and user space to
+ * be used by SGI's customers buying SGI Linux systems. One of the first
+ * few products to be open sourced by SGI was LKCD, or Linux Kernel Crash
+ * Dumps. LKCD comprises of a patch to the kernel to enable system
+ * dumping, along with 'lcrash', or Linux Crash, to analyze the system
+ * memory dump. A few additional system scripts and kernel modifications
+ * are also included to make the dump mechanism and dump data easier to
+ * process and use.
+ *
+ * As soon as LKCD was released into the open source community, a number
+ * of larger companies started to take advantage of it. Today, there are
+ * many community members that contribute to LKCD, and it continues to
+ * flourish and grow as an open source project.
+ *
+ * -----------------------------------------------------------------------
+ *
+ * SYSTEM DUMP LAYOUT
+ *
+ * System dumps are currently the combination of a dump header and a set
+ * of data pages which contain the system memory. The layout of the dump
+ * (for full dumps) is as follows:
+ *
+ * +-----------------------------+
+ * | generic dump header |
+ * +-----------------------------+
+ * | architecture dump header |
+ * +-----------------------------+
+ * | page header |
+ * +-----------------------------+
+ * | page data |
+ * +-----------------------------+
+ * | page header |
+ * +-----------------------------+
+ * | page data |
+ * +-----------------------------+
+ * | | |
+ * | | |
+ * | | |
+ * | | |
+ * | V |
+ * +-----------------------------+
+ * | PAGE_END header |
+ * +-----------------------------+
+ *
+ * There are two dump headers, the first which is architecture
+ * independent, and the other which is architecture dependent. This
+ * allows different architectures to dump different data structures
+ * which are specific to their chipset, CPU, etc.
+ *
+ * After the dump headers come a succession of dump page headers along
+ * with dump pages. The page header contains information about the page
+ * size, any flags associated with the page (whether it's compressed or
+ * not), and the address of the page. After the page header is the page
+ * data, which is either compressed (or not). Each page of data is
+ * dumped in succession, until the final dump header (PAGE_END) is
+ * placed at the end of the dump, assuming the dump device isn't out
+ * of space.
+ *
+ * This mechanism allows for multiple compression types, different
+ * types of data structures, different page ordering, etc., etc., etc.
+ * It's a very straightforward mechanism for dumping system memory.
+ * -----------------------------------------------------------------------
+ *
+ * DUMP IMPLEMENTATION
+ *
+ * Dumps are implemented using a "start at the top and work your way
+ * to the bottom" method. The starting location of kernel memory is
+ * determined, and each successive page is passed through to the
+ * dump_add_page() function, which determines whether to compress the
+ * page, throw it out, add the page header, etc. This mechanism is
+ * going to change over time as non-disruptive dumps are created, so
+ * it is best to read through the code (it is commented pretty well),
+ * and let the developers know if it isn't clear enough. We believe
+ * in well-documented, well-commented code.
+ *
+ * -----------------------------------------------------------------------
+ *
+ * DUMP TUNABLES
+ *
+ * This is the list of system tunables (via /proc) that are available
+ * for Linux systems. All the read, write, etc., functions are listed
+ * here. Currently, there are a few different tunables for dumps:
+ *
+ * dump_device (used to be dumpdev):
+ * The device for dumping the memory pages out to. This is almost
+ * always the primary swap partition for disruptive dumps.
+ *
+ * dump_compress (used to be dump_compress_pages):
+ * This is the flag which indicates which compression mechanism
+ * to use. This is a BITMASK, not an index (0,1,2,4,8,16,etc.).
+ * This is the current set of values:
+ *
+ * 0: DUMP_COMPRESS_NONE -- Don't compress any pages.
+ * 1: DUMP_COMPRESS_RLE -- This uses RLE compression.
+ * 2: DUMP_COMPRESS_GZIP -- This uses GZIP compression.
+ *
+ * dump_level:
+ * The amount of effort the dump module should make to save
+ * information for post crash analysis. This value is now
+ * a BITMASK value, not an index:
+ *
+ * 0: Do nothing, no dumping. (DUMP_LEVEL_NONE)
+ *
+ * 1: Print out the dump information to the dump header, and
+ * write it out to the dump_device. (DUMP_LEVEL_HEADER)
+ *
+ * 2: Write out the dump header and all kernel memory pages.
+ * (DUMP_LEVEL_KERN)
+ *
+ * 4: Write out the dump header and all kernel and user
+ * memory pages. (DUMP_LEVEL_USED)
+ *
+ * 8: Write out the dump header and all conventional/cached
+ * memory (RAM) pages in the system (kernel, user, free).
+ * (DUMP_LEVEL_ALL_RAM)
+ *
+ * 16: Write out everything, including non-conventional memory
+ * like firmware, proms, I/O registers, uncached memory.
+ * (DUMP_LEVEL_ALL)
+ *
+ * The dump_level will default to 1.
+ *
+ * REMIND: How about we change these to 1, 3, 7, 15, 31.
+ * If we reserve the bits for individual passes
+ * it's easer to test things like non-conventional
+ * memory dump on systems with limited disk space.
+ * If would be more consistent with dump_level being
+ * a bitmask. We might also consider changing the name
+ * to 'dump_passes' to make it more clear that the bitmask
+ * is not a index.
+ *
+ *
+ * dump_flags:
+ * These are the flags to use when talking about dumps. There
+ * are lots of possibilities. This is a BITMASK value, not an index.
+ *
+ * 1: Try to keep the system running _after_ we are done
+ * dumping -- for non-disruptive dumps. (DUMP_FLAGS_NONDISRUPT)
+ *
+ * -----------------------------------------------------------------------
+ */
+
+/*
+ * -----------------------------------------------------------------------
+ * H E A D E R F I L E S
+ * -----------------------------------------------------------------------
+ */
+
+/* header files */
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/devfs_fs_kernel.h>
+#include <linux/delay.h>
+#include <linux/reboot.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/dump.h>
+#include <linux/smp_lock.h>
+#include <linux/mm.h>
+#include <linux/proc_fs.h>
+#include <linux/file.h>
+#include <linux/sysctl.h>
+#include <linux/mman.h>
+#include <linux/init.h>
+#include <linux/ctype.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/utsname.h>
+#include <linux/highmem.h>
+#include <linux/version.h>
+
+#include <asm/hardirq.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+
+/*
+ * -----------------------------------------------------------------------
+ * D E F I N I T I O N S
+ * -----------------------------------------------------------------------
+ */
+/*
+ * Handle printing of 64-bit values
+ *
+ * NOTE: on ia64 %llx is recommended for ia32.
+ * on RedHat 7.2 %llx work in user space but not in the kernel.
+ * Perhaps this is dependent on the kernel version.
+ */
+#if BITS_PER_LONG == 64
+#define PU64X "%lx"
+#else
+#define PU64X "%Lx"
+#endif
+
+/*
+ * -----------------------------------------------------------------------
+ * V A R I A B L E S
+ * -----------------------------------------------------------------------
+ */
+
+/* Dump tunables */
+kdev_t dump_device; /* the actual kdev_t device number */
+int dump_level; /* the current dump level */
+int dump_compress; /* whether to try to compress each page */
+int dump_flags; /* whether to try to compress each page */
+
+/* Dump Notifier Tunables */
+long dump_scheduler_enabled = 0; /* Default: scheduler is disabled */
+long dump_interrupts_enabled = 1; /* Default: interrupts stay enabled */
+long dump_nondisruptive_enabled = 1; /* Default: non-disruptive enabled */
+
+/* Other global fields */
+void *dump_page_buf; /* dump page buffer for memcpy()! */
+void *dump_page_buf_0; /* dump page buffer returned by kmalloc */
+dump_header_t dump_header; /* the primary dump header */
+dump_header_asm_t dump_header_asm; /* the arch-specific dump header */
+loff_t dump_fpos; /* the offset in the output device */
+int dump_mbanks; /* number of physical memory banks */
+dump_mbank_t dump_mbank[MAXCHUNKS];/* describes layout of physical memory */
+long dump_unreserved_mem = 0; /* Save Pages even if it isn't reserved */
+long dump_unreferenced_mem = 0; /* Save Pages even if page_count == 0 */
+long dump_nonconventional_mem = 0; /* Save non-conventional mem (firmware) */
+volatile int dump_started = 0; /* Indicated we are about to dump */
+static struct dump_operations *dump_device_ops = 0;
+
+static int dump_compress_none(char *old, int oldsize, char *new, int newsize);
+
+static dump_compress_t dump_none_compression = {
+ compress_type: DUMP_COMPRESS_NONE,
+ compress_func: dump_compress_none,
+};
+
+/* our device operations and functions */
+static int dump_open(struct inode *i, struct file *f);
+static int dump_release(struct inode *i, struct file *f);
+static int dump_ioctl(struct inode *i, struct file *f,
+ unsigned int cmd, unsigned long arg);
+
+static struct file_operations dump_fops = {
+ open: dump_open,
+ release: dump_release,
+ ioctl: dump_ioctl,
+};
+
+/* function pointers and prototypes */
+int (*dump_compress_func)(char *old, int oldsize, char *new, int newsize);
+
+/* proc entries */
+static struct proc_dir_entry *dump_root; /* /proc/sys/dump root dir */
+static struct proc_dir_entry *dump_dd; /* dump_device tunable */
+static struct proc_dir_entry *dump_cp; /* dump_compress tunable */
+static struct proc_dir_entry *dump_l; /* dump_level tunable */
+static struct proc_dir_entry *dump_f; /* dump_flags tunable */
+
+/* static variables */
+static int dump_okay = FALSE; /* can we dump out to disk? */
+static char dpcpage[DUMP_DPC_PAGE_SIZE]; /* buffer used for compression */
+static unsigned long dump_save_flags; /* save_flags()/restore_flags() */
+
+/* used for dump compressors */
+static struct list_head dump_compress_list = LIST_HEAD_INIT(dump_compress_list);
+
+/* external variables */
+extern int panic_timeout; /* time before reboot */
+
+/* lkcd info structure -- this is used by lcrash for basic system data */
+lkcdinfo_t lkcdinfo = {
+ 0,
+ (sizeof(void *) * 8),
+#if defined(__LITTLE_ENDIAN)
+ __LITTLE_ENDIAN,
+#else
+ __BIG_ENDIAN,
+#endif
+ 0,
+ PAGE_SHIFT,
+ PAGE_SIZE,
+ PAGE_MASK,
+ PAGE_OFFSET,
+ 0
+};
+
+#if DUMP_DEBUG
+void dump_bp(void) {}
+#endif
+
+/*
+ * -----------------------------------------------------------------------
+ * / P R O C T U N A B L E F U N C T I O N S
+ * -----------------------------------------------------------------------
+ */
+
+/*
+ * Name: dump_read_proc()
+ * Func: Read the proc data for dump tunables.
+ */
+static int
+dump_read_proc(char *page, char **start, off_t off,
+ int count, int *eof, void *data)
+{
+ int len;
+ char *out = page;
+ struct proc_dir_entry *p = (struct proc_dir_entry *)data;
+
+
+ if (0 == strcmp(p->name, DUMP_LEVEL_NAME)) {
+ out += sprintf(out, "%d\n", dump_level);
+ len = out - page;
+ } else if (0 == strcmp(p->name, DUMP_FLAGS_NAME)) {
+ out += sprintf(out, "%d\n", dump_flags);
+ len = out - page;
+ } else if (0 == strcmp(p->name, DUMP_COMPRESS_NAME)) {
+ out += sprintf(out, "%d\n", dump_compress);
+ len = out - page;
+ } else if (0 == strcmp(p->name, DUMP_DEVICE_NAME)) {
+ out += sprintf(out, "0x%x\n", kdev_val(dump_device));
+ len = out - page;
+ } else {
+ return (0);
+ }
+ len -= off;
+ if (len < count) {
+ *eof = 1;
+ if (len <= 0) return 0;
+ } else {
+ len = count;
+ }
+ *start = page + off;
+ return (len);
+}
+
+/*
+ * -----------------------------------------------------------------------
+ * C O M P R E S S I O N F U N C T I O N S
+ * -----------------------------------------------------------------------
+ */
+
+/*
+ * Name: dump_compress_none()
+ * Func: Don't do any compression, period.
+ */
+static int
+dump_compress_none(char *old, int oldsize, char *new, int newsize)
+{
+ /* just return the old size */
+ return (oldsize);
+}
+
+/*
+ * -----------------------------------------------------------------------
+ * U T I L I T Y F U N C T I O N S
+ * -----------------------------------------------------------------------
+ */
+
+/*
+ * Dump Notifier Callbacks:
+ * Used by disk drivers during the dump notification
+ * to tune the dump driver. Names and functions are obvious.
+ */
+void dump_scheduler_enable(void)
+{
+ DUMP_DPRINTF("setting dump_scheduler_enabled = 1\n");
+ dump_scheduler_enabled = 1;
+}
+
+void dump_interrupts_disable(void)
+{
+ DUMP_DPRINTF("setting dump_interrupts_enabled = 0\n");
+ dump_interrupts_enabled = 0;
+}
+
+void dump_nondisruptive_disable(void)
+{
+ DUMP_DPRINTF("setting dump_nondisruptive_enabled = 0\n");
+ dump_nondisruptive_enabled = 0;
+}
+
+/*
+ * Name: dump_kernel_write()
+ *
+ * Func: Write out kernel information, check the device limitations,
+ * block sizes, etc.
+ * Writes DUMP_BUFFER_SIZE bytes in page buffer
+ *
+ * Returns: number of bytes written or -ERRNO.
+ * At EOF it returns 0.
+ */
+static ssize_t
+dump_kernel_write(int *eof)
+{
+ int err = 0, err1 = 0;
+ loff_t offset=0;
+
+ if (dump_device_ops == 0)
+ return (-EINVAL);
+
+ if (eof)
+ offset = (loff_t) (*eof);
+
+ /* wait till the dump device is ready to accept IO */
+ err1 = dump_device_ops->dump_ready(0);
+ if (err1 < 0) {
+ DUMP_PRINT("dump device not ready for IO\n");
+ return (err1);
+ }
+
+ err = dump_device_ops->dump_seek(dump_fpos, 0);
+ if (err < 0) {
+ DUMP_PRINT("seek to dump device failed, err %d\n", err);
+ return (-EFAULT);
+ }
+
+ /* write to the dump device */
+ err = dump_device_ops->dump_write(dump_page_buf, DUMP_BUFFER_SIZE,
+ &offset);
+ if (eof)
+ *eof = (int) offset;
+ if (err < 0) {
+ DUMP_PRINT("write to dump device failed, err %d\n", err);
+ return (err);
+ }
+
+ /* wait till the dump device is ready to accept next IO */
+ err1 = dump_device_ops->dump_ready(0);
+ if (err1 < 0) {
+ DUMP_PRINT("dump device not ready for IO\n");
+ return (err1);
+ }
+
+ /* err is the transferred bytes -- return those */
+ dump_fpos += err;
+ return (err);
+}
+
+/*
+ * Name: dump_add_end_marker()
+ * Func: add last dump page marker to the end of the dump buffer.
+ */
+static void
+dump_add_end_marker(unsigned long *toffset, int flags)
+{
+ dump_page_t dp;
+
+ /* set the end marker */
+ dp.dp_address = dp.dp_size = 0x0;
+ dp.dp_flags = flags;
+
+#if DUMP_DEBUG >= 6
+ dp.dp_byte_offset = dump_header.dh_num_bytes + DUMP_BUFFER_SIZE + PAGE_SIZE;
+ dp.dp_page_index = dump_header.dh_num_dump_pages;
+#endif
+
+ /* clear the buffer and copy the page header */
+ memcpy((void *)(dump_page_buf + *toffset),
+ (const void *)&dp, sizeof(dump_page_t));
+ *toffset += sizeof(dump_page_t);
+
+#if DUMP_DEBUG >= 6
+ dump_header.dh_num_bytes += sizeof(dump_page_t);
+#endif
+ dump_header.dh_num_dump_pages++;
+
+ return;
+}
+
+static inline int
+kernel_page(struct page *p)
+{
+ if (PageReserved(p) || (!PageLRU(p) && PageInuse(p)))
+ return 1;
+ else
+ return 0;
+}
+
+static inline int
+referenced_page(struct page *p)
+{
+ if (PageInuse(p)) {
+ if (!PageReserved(p) && PageLRU(p))
+ return 1;
+ else
+ return 0;
+ } else
+ return 0;
+}
+
+static inline int
+unreferenced_page(struct page *p)
+{
+ if (!PageInuse(p)) {
+ if (!PageReserved(p))
+ return 1;
+ else
+ return 0;
+ } else
+ return 0;
+}
+
+long dump_add_page_debug = 0;
+long dump_add_page_test_pattern = 0;
+
+/*
+ * Name: dump_add_page()
+ * Func: Add a hardware page to the dump buffer.
+ *
+ * NB: page is a DUMP_PAGE_SIZE page,
+ * not a system page (PAGE_SIZE).
+ *
+ * REMIND:
+ * We should likely move some of this to
+ * arch specific code and/or clean it up.
+ */
+static int
+dump_add_page(unsigned long page_index, unsigned long *toffset, int pass)
+{
+#if defined(CONFIG_X86) || defined(CONFIG_ALPHA)
+ extern int page_is_ram(unsigned long);
+#endif
+ unsigned long size;
+ dump_page_t dp;
+ void *vaddr;
+ u64 paddr = (((u64)page_index) << DUMP_PAGE_SHIFT);
+ struct page *p;
+
+#if !defined(CONFIG_DISCONTIGMEM) && !defined(CONFIG_IA64)
+ p = (struct page *) &(mem_map[page_index]);
+
+ /*
+ * If the address is in highmem, map it before copying to
+ * the dump buffer. In essence, the dump buffer is the
+ * bounce buffer.
+ */
+#ifdef CONFIG_HIGHMEM
+ if (PageHighMem(p)) {
+ /*
+ * Since this can be executed from IRQ context,
+ * reentrance on the same CPU must be avoided:
+ */
+ vaddr = kmap_atomic(p, KM_USER0);
+ }
+ else
+#endif
+#if defined(CONFIG_X86) || defined(CONFIG_ALPHA)
+ if (!page_is_ram(page_index)) {
+ return (1);
+ }
+ else
+#endif
+ /* low memory */
+ vaddr = page_address(p);
+
+#else /* CONFIG_DISCONTIGMEM || CONFIG_IA64 */
+ vaddr = __va(paddr);
+ p = virt_to_page(vaddr);
+#endif
+ dp.dp_address = paddr;
+ dp.dp_flags = DUMP_DH_RAW;
+
+#if DUMP_DEBUG >= 6
+ /*
+ * Helpful when looking at hex dump of /dev/vdump.
+ * Dump Header Swap Header
+ */
+ dp.dp_byte_offset = dump_header.dh_num_bytes + DUMP_BUFFER_SIZE +
+ DUMP_HEADER_OFFSET;
+ dp.dp_page_index = dump_header.dh_num_dump_pages;
+
+ switch(pass) {
+ case 1: break;
+ case 2: return(1); /* Already Dumped */
+ case 3: return(1); /* Already Dumped */
+ case 4: break;
+ }
+#else
+ /*
+ * Selective dump:
+ * Some systems, have huge memories, NUMA for example, where
+ * a dump of all of memory isn't likely to fit on a swap partition.
+ * This is a simple 1st attempt at ordering the dump so the most
+ * important pages are dumped first.
+ *
+ * pass1: Kernel Pages
+ * pass2: Remaining referenced pages
+ * pass3: the rest of conventional memory
+ * pass4: non-conventional memory,
+ */
+ switch (pass) {
+ case 1:
+ if (kernel_page(p))
+ break;
+ else
+ return(1);
+ case 2:
+ if (referenced_page(p))
+ break;
+ else
+ return(1);
+ case 3:
+ if (unreferenced_page(p))
+ break;
+ else
+ return(1);
+ case 4:
+ break;
+
+ }
+#endif
+
+#if !defined(CONFIG_DISCONTIGMEM) && !defined(CONFIG_IA64)
+ if (!kern_addr_valid(dp.dp_address)) {
+ /* dump of I/O memory not supported yet */
+ printk(KERN_ALERT "dump_add_page: !kern_addr_valid"
+ "(dp.dp_address: " PU64X "\n", dp.dp_address);
+ return(1);
+ }
+#endif
+
+#if DUMP_DEBUG
+ if (dump_add_page_debug)
+ printk(KERN_ALERT "dump_add_page(page_index:%lx, "
+ "*toffset:%lx):\n", page_index, *toffset);
+#endif
+
+ /*
+ * Don't compress the page if any part of it overlaps
+ * with the current stack.
+ */
+ if ((((unsigned long)vaddr < (unsigned long)current->thread_info +
+ THREAD_SIZE) && ((unsigned long)vaddr + DUMP_PAGE_SIZE >
+ (unsigned long)current->thread_info))) {
+ size = DUMP_PAGE_SIZE;
+ }
+ else {
+ size = dump_compress_func((char *)vaddr, DUMP_PAGE_SIZE,
+ (char *)dpcpage, DUMP_DPC_PAGE_SIZE);
+ if (!size) {
+ /* dump compression failed -- default to raw mode */
+ size = DUMP_PAGE_SIZE;
+ }
+ /* set the compressed flag if the page did compress */
+ if (size < DUMP_PAGE_SIZE)
+ dp.dp_flags = DUMP_DH_COMPRESSED;
+ }
+
+ /* set the universal size */
+ dp.dp_size = size;
+
+ /* copy the page header */
+ memcpy((void *)(dump_page_buf + *toffset), (const void *)&dp,
+ sizeof(dump_page_t));
+
+ *toffset += sizeof(dump_page_t);
+
+ if (dp.dp_flags & DUMP_DH_COMPRESSED) {
+ /* copy the compressed page */
+ memcpy((void *)(dump_page_buf + *toffset),
+ (const void *)dpcpage, size);
+ } else {
+ /* copy directly from memory */
+ DUMP_memcpy((void *)(dump_page_buf + *toffset),
+ (const void *)vaddr, size);
+ }
+
+#if DUMP_DEBUG
+ /*
+ * Write a Test Pattern:
+ * Page data is full of bytes with the page number.
+ */
+ if (dump_add_page_test_pattern) {
+ unsigned char num_pages = (char) (dump_header.dh_num_dump_pages
+ & 0Xff);
+ char *cp = (dump_page_buf + *toffset);
+ int i;
+
+ for (i = 0; i < size; i++)
+ *cp++ = num_pages;
+ }
+#endif
+
+#ifdef CONFIG_HIGHMEM
+ if (PageHighMem(p)) {
+ /*
+ * Since this can be executed from IRQ context,
+ * reentrance on the same CPU must be avoided:
+ */
+ kunmap_atomic(vaddr, KM_USER0);
+ }
+#endif
+ *toffset += size;
+
+#if DUMP_DEBUG >= 6
+ if (dump_add_page_debug)
+ printk(KERN_ALERT "dump_add_page: *toffset:%lx += size:%lx:\n",
+ *toffset, size);
+
+ dump_header.dh_num_bytes += (size + sizeof(dump_page_t));
+#endif
+ dump_header.dh_num_dump_pages++;
+
+ return (0);
+}
+
+/*
+ * Name: dump_silence_system()
+ * Func: Silence the system, or make CPUs spin, etc. The intention
+ * here is to get things to a "quiet" state, so we can dump.
+ */
+void
+dump_silence_system(void)
+{
+ unsigned int stage = 0;
+ int cpu = smp_processor_id();
+
+ if (in_interrupt()) {
+ printk(KERN_ALERT "Dumping from interrupt handler !\n");
+ printk(KERN_ALERT "Uncertain scenario - but will try my best\n");
+ /*
+ * Must be an unrelated interrupt, not in the middle of io !
+ * If we've panic'ed in the middle of io we should take
+ * another approach
+ */
+ }
+ /* see if there's something to do before we re-enable interrupts */
+ (void)__dump_silence_system(stage);
+
+ /* we set this to FALSE so we don't ever re-enter this code! */
+ dump_okay = FALSE;
+ dumping_cpu = cpu;
+
+ local_irq_save(dump_save_flags);
+ local_irq_enable(); /* enable interrupts just in case ... */
+
+ /* now increment the stage and do stuff after interrupts are enabled */
+ stage++;
+ (void)__dump_silence_system(stage);
+
+ /* time to leave */
+ return;
+}
+
+/*
+ * Name: dump_resume_system()
+ * Func: Resume the system state.
+ */
+void
+dump_resume_system(void)
+{
+ unsigned int stage = 0;
+
+ /* let the architectures return their proper system state */
+ (void)__dump_resume_system(stage);
+
+ local_irq_restore(dump_save_flags);
+ dump_in_progress = FALSE;
+ dump_okay = TRUE;
+
+ return;
+}
+
+static void
+dump_speedo(void)
+{
+ static int i = 0;
+
+ switch (++i%4) {
+ case 0:
+ printk("|\b");
+ break;
+ case 1:
+ printk("\\\b");
+ break;
+ case 2:
+ printk("-\b");
+ break;
+ case 3:
+ printk("/\b");
+ break;
+ }
+}
+
+/*
+ * -----------------------------------------------------------------------
+ * H E A D E R F U N C T I O N S
+ * -----------------------------------------------------------------------
+ */
+
+/*
+ * Name: dump_configure_header()
+ * Func: Update the header with the appropriate information.
+ */
+static int
+dump_configure_header(char *panic_str, struct pt_regs *regs)
+{
+ struct timeval dh_time;
+ /* make sure the dump header isn't TOO big */
+ if ((sizeof(dump_header_t) +
+ sizeof(dump_header_asm_t)) > DUMP_BUFFER_SIZE) {
+ DUMP_PRINTN("dump_configure_header(): combined "
+ "headers larger than DUMP_BUFFER_SIZE!");
+ return (0);
+ }
+
+ /* configure dump header values */
+ dump_header.dh_magic_number = DUMP_MAGIC_NUMBER;
+ dump_header.dh_version = DUMP_VERSION_NUMBER;
+ dump_header.dh_memory_start = PAGE_OFFSET;
+ dump_header.dh_memory_end = DUMP_MAGIC_NUMBER;
+ dump_header.dh_header_size = sizeof(dump_header_t);
+ dump_header.dh_page_size = PAGE_SIZE;
+ dump_header.dh_dump_level = dump_level;
+ dump_header.dh_current_task = (unsigned long) current;
+ dump_header.dh_dump_compress = dump_compress;
+ dump_header.dh_dump_flags = dump_flags;
+ dump_header.dh_dump_device = kdev_val(dump_device);
+
+#if DUMP_DEBUG >= 6
+ dump_header.dh_num_bytes = 0;
+#endif
+ dump_header.dh_num_dump_pages = 0;
+ do_gettimeofday(&dh_time);
+ dump_header.dh_time.tv_sec = dh_time.tv_sec;
+ dump_header.dh_time.tv_usec = dh_time.tv_usec;
+
+#ifndef UTSNAME_ENTRY_SZ
+#define UTSNAME_ENTRY_SZ 65
+#endif
+ memcpy((void *)&(dump_header.dh_utsname_sysname),
+ (const void *)&(system_utsname.sysname), UTSNAME_ENTRY_SZ);
+ memcpy((void *)&(dump_header.dh_utsname_nodename),
+ (const void *)&(system_utsname.nodename), UTSNAME_ENTRY_SZ);
+ memcpy((void *)&(dump_header.dh_utsname_release),
+ (const void *)&(system_utsname.release), UTSNAME_ENTRY_SZ);
+ memcpy((void *)&(dump_header.dh_utsname_version),
+ (const void *)&(system_utsname.version), UTSNAME_ENTRY_SZ);
+ memcpy((void *)&(dump_header.dh_utsname_machine),
+ (const void *)&(system_utsname.machine), UTSNAME_ENTRY_SZ);
+ memcpy((void *)&(dump_header.dh_utsname_domainname),
+ (const void *)&(system_utsname.domainname), UTSNAME_ENTRY_SZ);
+
+ if (panic_str) {
+ memcpy((void *)&(dump_header.dh_panic_string),
+ (const void *)panic_str, DUMP_PANIC_LEN);
+ }
+
+ dump_header_asm.dha_magic_number = DUMP_ASM_MAGIC_NUMBER;
+ dump_header_asm.dha_version = DUMP_ASM_VERSION_NUMBER;
+ dump_header_asm.dha_header_size = sizeof(dump_header_asm_t);
+
+ /* copy the registers if they are valid */
+ if (regs) {
+ memcpy((void *)&(dump_header_asm.dha_regs),
+ (const void *)regs, sizeof(struct pt_regs));
+ }
+
+ /* configure architecture-specific dump header values */
+ if (!__dump_configure_header(regs))
+ return (0);
+
+ return (1);
+}
+
+/*
+ * Name: dump_write_header()
+ * Func: Write out the dump header.
+ *
+ * Returns:
+ * -1: failed
+ * 0: wrote o bytes (truncated)
+ * +1: wrote header
+ */
+static int
+dump_write_header(void)
+{
+ int state;
+ loff_t toffset;
+
+ /* clear the dump page buffer */
+ memset(dump_page_buf, 0, DUMP_BUFFER_SIZE);
+
+ /* copy the dump header directly into the dump page buffer */
+ memcpy(dump_page_buf, (const void *)&dump_header,
+ sizeof(dump_header_t));
+
+ memcpy((void *)(dump_page_buf + sizeof(dump_header_t)),
+ (const void *)&dump_header_asm, sizeof(dump_header_asm_t));
+
+ /* save our file pointer */
+ toffset = dump_fpos;
+
+ /*
+ * ALWAYS write out the dump header at DUMP_HEADER_OFFSET,
+ * this is after the longest swap header possibly written by mkswap;
+ * likely the largest PAGE_SIZE supported by the architecture.
+ */
+ dump_fpos = DUMP_HEADER_OFFSET;
+
+ /* do the real write here */
+ state = dump_kernel_write(NULL);
+ dump_fpos = toffset;
+ if (state < 0) {
+ DUMP_PRINTF("dump_kernel_write() failed!\n");
+ return (-1);
+ } else if (!state) {
+ /* wrote zero bytes - failed */
+ return (0);
+ }
+ /* Wrote the header - success */
+ return (1);
+}
+
+/*
+ * -----------------------------------------------------------------------
+ * E X E C U T E F U N C T I O N S
+ * -----------------------------------------------------------------------
+ */
+
+static int
+dump_write_mbank(int *dump_truncated, int pass, u64 mbank_start,
+ u64 mbank_end, unsigned long *buf_loc)
+{
+ int counter = 0, n_bytes = 0;
+ u64 mem_loc;
+
+ for (mem_loc = mbank_start; mem_loc < mbank_end;
+ mem_loc += DUMP_PAGE_SIZE) {
+
+ /* add the page (if it's real RAM) */
+ if (dump_add_page((mem_loc >> DUMP_PAGE_SHIFT),
+ buf_loc, pass)) {
+ /* didn't add a page to buffer */
+ continue;
+ }
+
+ /* see if we've filled the buffer */
+ if (*buf_loc >= DUMP_BUFFER_SIZE) {
+ int near_eof = 0;
+
+ /* write out the dump page buffer */
+ n_bytes = dump_kernel_write(&near_eof);
+ if (n_bytes < 0) {
+ DUMP_PRINTN("Write of dump pages failed!");
+ return(-1);
+ } else if (n_bytes == 0) {
+ DUMP_PRINTN("EOF on Write of dump pages; "
+ "dump terminated!");
+ return(0);
+ }
+ if (near_eof) {
+ DUMP_PRINTN("Near EOF on Write of dump pages; "
+ "truncating dump,");
+ *dump_truncated = 1;
+ }
+
+ /* bump the counter for writing out the header */
+ counter++;
+
+ /*
+ * Update the header every once in a while -- this
+ * _must_ be done before we write the overflow end of
+ * the dump_page_buf into the top of dump_page_buf,
+ * as dump_write_header() uses dump_page_buf to
+ * write the default/asm dump headers. After we are
+ * done updating the header, _then_ we can move the
+ * leftover dump data into the top of dump_page_buf.
+ *
+ * NOTE: a period is printed to indicate that the header
+ * was updated. Speedo shows page outactivity.
+ */
+ if ((counter & 0x3f) == 0) {
+ n_bytes = dump_write_header();
+ if (n_bytes < 0) {
+ DUMP_PRINTN("Dump header update "
+ "failed!");
+ return (-1);
+ } else if (n_bytes == 0) {
+ DUMP_PRINTN("Dump header update "
+ "failed; bizarre");
+ return (0);
+ }
+ DUMP_PRINT(".");
+ } else {
+ if ((counter & 0x07) == 0)
+ dump_speedo();
+ }
+
+ /* clear the dump page buffer */
+ memset(dump_page_buf, 0, DUMP_BUFFER_SIZE);
+
+ /* adjust leftover data back to the top of the page */
+ if (*buf_loc > DUMP_BUFFER_SIZE) {
+ /* copy the dump page buffer remnants */
+ memcpy((void *)dump_page_buf,
+ (const void *)(dump_page_buf +
+ DUMP_BUFFER_SIZE),
+ *buf_loc - DUMP_BUFFER_SIZE);
+
+ /* set the new buffer location */
+ *buf_loc -= DUMP_BUFFER_SIZE;
+ } else {
+ /* reset the buffer location counter */
+ *buf_loc = 0;
+ }
+ }
+ if (*dump_truncated) {
+ break;
+ }
+ }
+ DUMP_PRINT(" ");
+ return 1;
+}
+
+/*
+ * Name: dump_execute_memdump()
+ * Func: Perform the actual memory dump. This walks through the
+ * memory pages and dumps the data to disk (using other functions).
+ *
+ * Returns:
+ * -1: failed
+ * 0: dump truncated
+ * 1: success
+ */
+static int
+dump_execute_memdump(void)
+{
+ int n_bytes = 0, i, retval = 1;
+ unsigned long buf_loc;
+ int dump_truncated = 0;
+ int pass = 0;
+
+ DUMP_PRINTN("Compression value is 0x%x, Writing dump header ",
+ dump_compress);
+
+ /* update the header to disk the first time */
+ n_bytes = dump_write_header();
+ DUMP_PRINT("\n");
+
+ if (n_bytes < 0) {
+ DUMP_PRINTF("Initial dump header update failed!\n");
+ return (-1);
+ } else if (n_bytes == 0) {
+ return (0);
+ }
+
+ /* if we only want the header, return */
+ if (dump_level & DUMP_LEVEL_HEADER)
+ return (1);
+
+ /* set beginning offset to keep compats right with swap devices */
+ dump_fpos = DUMP_HEADER_OFFSET + DUMP_BUFFER_SIZE;
+
+ /* clear the dump page buffer */
+ memset(dump_page_buf, 0, DUMP_BUFFER_SIZE);
+
+ /* set the buffer location */
+ buf_loc = 0;
+
+ for (pass = 1; pass <= 4; pass++) {
+ if ((pass == 2) && dump_unreserved_mem == 0)
+ continue;
+ if ((pass == 3) && dump_unreferenced_mem == 0)
+ continue;
+ if (pass == 4) {
+ if (dump_nonconventional_mem == 0) break;
+ /* Contiguous Mem Sys have 1 mbank */
+ if (dump_mbanks == 1) break;
+ }
+ /* Algorithm suggested by Jack Steiner <steiner@sgi.com */
+ switch(pass) {
+ case 1: DUMP_PRINTN("Pass 1: Saving Kernel Pages: ");
+ break;
+ case 2: DUMP_PRINTN("Pass 2: Saving Remaining "
+ "Referenced Pages: ");
+ break;
+ case 3: DUMP_PRINTN("Pass 3: Saving Remaining "
+ "Unreferenced Pages: ");
+ break;
+ case 4: DUMP_PRINTN("Pass 4: Saving Unconventional "
+ "Memory: ");
+ break;
+ }
+ for (i = 0; i < dump_mbanks; i++) {
+ u64 mem_bank_start = dump_mbank[i].start;
+ u64 mem_bank_end = dump_mbank[i].end;
+ int type = dump_mbank[i].type;
+
+ if ((type != DUMP_MBANK_TYPE_CONVENTIONAL_MEMORY) &&
+ (pass != 4)) continue;
+ if ((type == DUMP_MBANK_TYPE_CONVENTIONAL_MEMORY) &&
+ (pass == 4)) continue;
+
+ DUMP_PRINTN("Memory Bank[%d]: " PU64X " ... " PU64X ": "
+ ,i, mem_bank_start, mem_bank_end);
+
+ if ((retval = dump_write_mbank(&dump_truncated, pass,
+ mem_bank_start, mem_bank_end, &buf_loc)) <= 0)
+ return retval;
+ if (dump_truncated)
+ break;
+ }
+ if (dump_truncated)
+ break;
+ DUMP_PRINT("\n");
+ }
+
+ /*
+ * we have written out most of the dump pages, a few may still be in the
+ * page buffer and it's possible we had to truncate the dump because we
+ * got very close to the end of the dump partition. Now we add a EOF
+ * marker to the page out buffer and flush out the remaining pages.
+ *
+ * We need to write the DUMP_DH_END even for truncated data because
+ * the reader won't get an EOF if he reads the data in smaller chunks
+ * than the DUMP_BUFFER_SIZE it's written in.
+ */
+ if (dump_truncated)
+ dump_add_end_marker(&buf_loc, (DUMP_DH_END | DUMP_DH_TRUNCATED));
+ else
+ dump_add_end_marker(&buf_loc, DUMP_DH_END);
+
+ n_bytes = dump_kernel_write(NULL);
+
+ if (n_bytes < 0) {
+ DUMP_PRINTN("Final write of last of page buffer and "
+ "DUMP_DH_END failed!");
+ return (-1);
+ } else if (n_bytes == 0) {
+ DUMP_PRINTN("Hit EOF writing DUMP_DH_END; bad luck\n");
+ return (0);
+ }
+
+ /*
+ * Writing out DUMP_DH_END may have pushed us past the end of the first
+ * part of the page buffer, if it did we have to write out one last
+ * DUMP_BUFFER with the spill over page.
+ */
+ if (buf_loc > DUMP_BUFFER_SIZE) {
+ /* clear the first part of the buffer */
+ memset(dump_page_buf, 0, DUMP_BUFFER_SIZE);
+
+ /*
+ * Copy the dump page buffer remnants in the second
+ * part of the buffer to the first part.
+ */
+ memcpy((void *)dump_page_buf,
+ (const void *)(dump_page_buf + DUMP_BUFFER_SIZE),
+ buf_loc - DUMP_BUFFER_SIZE);
+
+ n_bytes = dump_kernel_write(NULL);
+ if (n_bytes < 0) {
+ DUMP_PRINTN("Final write of spillover page failed!");
+ return (-1);
+ } else if (n_bytes == 0) {
+ DUMP_PRINTN("Hit EOF writing spill over page with "
+ "DUMP_DH_END; very bad luck!\n");
+ return (0);
+ }
+ }
+ if (dump_truncated)
+ return(0);
+
+ /* success */
+ return (1);
+}
+
+/*
+ * Name: dump_execute()
+ * Func: Execute the dumping process. This makes sure all the appropriate
+ * fields are updated correctly, and calls dump_execute_memdump(),
+ * which does the real work.
+ *
+ * if( dump_flags & DUMP_FLAGS_NONDISRUPT ) {
+ * Returns:
+ * -1: failed
+ * 0: dump truncated
+ * 1: success
+ * }
+ */
+int
+dump_execute(char *panic_str, struct pt_regs *regs)
+{
+ int state = 1;
+ int scheduler_disabled = 1;
+
+ dump_started = 1;
+
+ /* make sure we can dump */
+ if (dump_okay == FALSE)
+ return(-1);
+
+ /*
+ * we can delay this till arch-specific header configuration
+ * where we use NMI ipi to mark the current process
+ * for rescheduling and schedular is disabled based on this value
+ * However setting this early here only...
+ */
+ dump_in_progress = TRUE;
+
+ if(!dump_configure_header(panic_str, regs)) {
+ DUMP_PRINTN("dump header could not be configured!");
+ dump_in_progress = FALSE;
+ return(-1);
+ }
+
+ /* silence the system */
+ dump_silence_system();
+
+ /* tell interested parties that a dump is about to start */
+ if (dump_flags & DUMP_FLAGS_NONDISRUPT) {
+ notifier_call_chain(&dump_notifier_list, DUMP_BEGIN_NONDISRUPT,
+ &dump_device);
+ } else {
+ notifier_call_chain(&dump_notifier_list, DUMP_BEGIN,
+ &dump_device);
+ }
+
+ /*
+ * if dump device notifier indicated the scheduler needs to be
+ * enabled then we need to turn it back on.
+ */
+ if (dump_scheduler_enabled) {
+ dump_resume_system();
+ scheduler_disabled = 0;
+ }
+
+ /*
+ * Make sure dump device notifier indicated that Non-Disruptive
+ * Dumps are Supported.
+ */
+ if (!dump_nondisruptive_enabled && (dump_flags &
+ DUMP_FLAGS_NONDISRUPT) ) {
+ DUMP_PRINTN("Non-Disruptive Dumps are not Supported by "
+ "Dump Device 0x%x\n", kdev_val(dump_device));
+ state = -1; /* Dump Aborted */
+ } else {
+ /* bail out if we're not going to do any dumping. */
+ if (dump_level != DUMP_LEVEL_NONE) {
+ /* inform users of what we are about to do */
+ DUMP_PRINTN("Dumping to device 0x%x on CPU %d ...",
+ kdev_val(dump_device), smp_processor_id());
+
+ dump_device_ops->dump_start(0);
+
+ /* start walking through the page tables */
+ state = dump_execute_memdump();
+
+ DUMP_PRINT("\n");
+
+ /* update header to disk for the last time */
+ if (dump_write_header() < 0) {
+ DUMP_PRINTF("Final dump header update "
+ "failed!\n");
+ }
+
+ dump_device_ops->dump_end(0);
+
+ if (state < 0) {
+ DUMP_PRINTF("Dump Failed!\n");
+ } else if (state == 0) {
+ DUMP_PRINTF("Dump Truncated (likely out of "
+ "space).\n");
+ } else {
+ DUMP_PRINTF("Dump Complete; %d dump pages "
+ "saved.\n",
+ dump_header.dh_num_dump_pages);
+ }
+ }
+ }
+
+ /* tell interested parties that a dump has completed */
+ notifier_call_chain(&dump_notifier_list, DUMP_END, &dump_device);
+
+ /* put the system state back */
+ if (scheduler_disabled)
+ dump_resume_system();
+
+ /*
+ * Reboot the system if this is a disrupted dump.
+ * Non-disruptive dumps have to be set up special
+ * swap partition that isn't being used and can be
+ * used for testing.
+ */
+ if (!(dump_flags & DUMP_FLAGS_NONDISRUPT)) {
+ int timeout = (panic_timeout > 0) ? panic_timeout : 10;
+
+ DUMP_PRINTF("Dump: Rebooting in %d seconds ...", timeout);
+ mdelay(timeout * 1000);
+ machine_restart(NULL);
+ }
+ dump_started = 0;
+ return (state);
+}
+
+/*
+ * Name: dump_register_compression()
+ * Func: Register a dump compression mechanism.
+ */
+void
+dump_register_compression(dump_compress_t *item)
+{
+ /* let's make sure our list is valid */
+ if (!item)
+ return;
+
+ /* add our item */
+ list_add(&(item->list), &dump_compress_list);
+
+ /* print information to callers */
+ DUMP_PRINTF("Registering dump compression type 0x%x\n",
+ item->compress_type);
+}
+
+/*
+ * Name: dump_unregister_compression()
+ * Func: Remove a dump compression mechanism, and re-assign the dump
+ * compression pointer if necessary.
+ */
+void
+dump_unregister_compression(int compression_type)
+{
+ struct list_head *tmp;
+ dump_compress_t *dc;
+
+ /* let's make sure our list is valid */
+ if (compression_type == DUMP_COMPRESS_NONE) {
+ DUMP_PRINTN("Compression list is invalid!");
+ return;
+ }
+
+ /* try to remove the compression item */
+ list_for_each(tmp, &dump_compress_list) {
+ dc = list_entry(tmp, dump_compress_t, list);
+ if (dc->compress_type == compression_type) {
+ list_del(&(dc->list));
+ DUMP_PRINTN("De-registering dump compression type "
+ "0x%x\n", compression_type);
+ return;
+ }
+ }
+}
+
+/*
+ * Name: dump_compress_init()
+ * Func: Initialize (or re-initialize) compression scheme.
+ */
+static int
+dump_compress_init(int compression_type)
+{
+ struct list_head *tmp;
+ dump_compress_t *dc;
+
+ /* try to remove the compression item */
+ list_for_each(tmp, &dump_compress_list) {
+ dc = list_entry(tmp, dump_compress_t, list);
+ if (dc->compress_type == compression_type) {
+ dump_compress_func = dc->compress_func;
+ dump_compress = compression_type;
+
+ DUMP_PRINTF("dump_compress = %d\n", dump_compress);
+ DUMP_BP();
+ return (0);
+ }
+ }
+
+ /*
+ * nothing on the list -- return ENODATA to indicate an error
+ *
+ * NB:
+ * EAGAIN: reports "Resource temporarily unavailable" which
+ * isn't very enlightening.
+ */
+ DUMP_PRINTF("compression_type:%d not found\n", compression_type);
+ DUMP_BP();
+
+ return (-ENODATA);
+}
+
+/*
+ * Name: dump_open_kdev()
+ * Func: Try to open the kdev_t argument as the real dump device.
+ * This is where all the work is done for setting up the dump
+ * device. It's assumed at this point that by passing in the
+ * dump device's major/minor number, we can open it up, check
+ * it out, and use it for whatever purposes.
+ */
+static int
+dump_open_kdev(kdev_t tmp_dump_device)
+{
+ unsigned long dump_page_addr;
+ int err;
+
+ if (dump_device_ops == 0) {
+ DUMP_PRINT("dump device driver is not loaded\n");
+ return (-EINVAL);
+ }
+
+ /* if this is the second call to this function, clean up ... */
+ if ((dump_okay == TRUE) && (dump_page_buf_0 != (void *)NULL))
+ kfree((const void *)dump_page_buf_0);
+
+ /*
+ * Allocate buffer to be used for copying pages (only once ...)
+ *
+ * An extra:
+ * 2 * DUMP_PAGE_SIZE:
+ * is needed for the page overflow of last page, it's page header
+ * and the EOF page header.
+ *
+ * and an extra:
+ * 1 * PAGE_SIZE:
+ * is needed for rounding up the start of the dump_page_buf to
+ * a system page (PAGE_SIZE) boundry.
+ *
+ */
+ dump_page_buf = dump_page_buf_0 = (void *)kmalloc(DUMP_BUFFER_SIZE +
+ 2 * DUMP_PAGE_SIZE + PAGE_SIZE, GFP_KERNEL);
+
+ if (dump_page_buf_0 == (void *)0) {
+ DUMP_PRINTF("Cannot kmalloc() dump page buffer!\n");
+ dump_okay = FALSE;
+ return (-ENOMEM);
+ }
+
+ /* align the dump page addresses */
+ dump_page_addr = (unsigned long) dump_page_buf;
+ if (dump_page_addr % PAGE_SIZE)
+ dump_page_buf = (void *) PAGE_ALIGN(dump_page_addr);
+
+ /* assign the new dump file structure */
+ dump_device = tmp_dump_device;
+
+ err = dump_device_ops->dump_open();
+ if (err < 0) {
+ dump_okay = FALSE;
+ return (-EINVAL);
+ }
+ err = dump_device_ops->dump_ioctl(DIOSDUMPMEM,
+ (unsigned long)dump_page_buf);
+ if (err < 0) {
+ dump_okay = FALSE;
+ return (-EINVAL);
+ }
+
+ err = dump_device_ops->dump_ioctl(DIOSDUMPDEV,
+ kdev_val(tmp_dump_device));
+ if (err < 0) {
+ dump_okay = FALSE;
+ return (-EINVAL);
+ }
+ dump_okay = TRUE;
+
+ /* after opening the block device, return */
+ return 0;
+}
+
+/*
+ * Name: dump_release()
+ * Func: Release the dump device -- it's never necessary to call
+ * this function, but it's here regardless.
+ */
+static int
+dump_release(struct inode *i, struct file *f)
+{
+ return (0);
+}
+
+/*
+ * Name: dump_ioctl()
+ * Func: Allow all dump tunables through a standard ioctl() mechanism.
+ * This is far better than before, where we'd go through /proc,
+ * because now this will work for multiple OS and architectures.
+ */
+static int
+dump_ioctl(struct inode *i, struct file *f, unsigned int cmd, unsigned long arg)
+{
+ /* check capabilities */
+ if (!capable(CAP_SYS_ADMIN))
+ return (-EPERM);
+
+ /*
+ * This is the main mechanism for controlling get/set data
+ * for various dump device parameters. The real trick here
+ * is setting the dump device (DIOSDUMPDEV). That's what
+ * triggers everything else.
+ */
+ switch (cmd) {
+ /* set dump_device */
+ case DIOSDUMPDEV:
+ /* check flags */
+ if (!(f->f_flags & O_RDWR))
+ return (-EPERM);
+
+ __dump_open();
+ return (dump_open_kdev(to_kdev_t((dev_t)arg)));
+
+ /* get dump_device */
+ case DIOGDUMPDEV:
+ return (put_user((long)kdev_val(dump_device), (long *)arg));
+
+ /* set dump_level */
+ case DIOSDUMPLEVEL:
+ /* check flags */
+ if (!(f->f_flags & O_RDWR))
+ return (-EPERM);
+
+ /* make sure we have a positive value */
+ if (arg < 0)
+ return (-EINVAL);
+ dump_level = (int)arg;
+
+ /*
+ * REMIND: Still in development:
+ * We will consider reserved pages a initial proxy
+ * for kernel pages.
+ */
+ if (dump_level > DUMP_LEVEL_KERN)
+ dump_unreserved_mem = 1;
+ else
+ dump_unreserved_mem = 0;
+
+ /*
+ * REMIND: Still in development:
+ * Using refcount > 1 as a proxy for kernel & user
+ * pages.
+ */
+ if (dump_level > DUMP_LEVEL_USED)
+ dump_unreferenced_mem = 1;
+ else
+ dump_unreferenced_mem = 0;
+
+ /*
+ * REMIND: Still in development:
+ * This may not be 100% stable on all ia64
+ * memory banks. Accessing uncached memory
+ * with cached accesses can cause subsequent
+ * bus errors when the cache is flushed.
+ */
+ if (dump_level > DUMP_LEVEL_ALL_RAM)
+ dump_nonconventional_mem = 1;
+ else
+ dump_nonconventional_mem = 0;
+ break;
+
+ /* get dump_level */
+ case DIOGDUMPLEVEL:
+ return (put_user((long)dump_level, (long *)arg));
+
+ /* set dump_flags */
+ case DIOSDUMPFLAGS:
+ /* check flags */
+ if (!(f->f_flags & O_RDWR))
+ return (-EPERM);
+
+ /* make sure we have a positive value */
+ if (arg < 0)
+ return (-EINVAL);
+
+ dump_flags = (int)arg;
+ break;
+
+ /* get dump_flags */
+ case DIOGDUMPFLAGS:
+ return (put_user((long)dump_flags, (long *)arg));
+
+ /* set the dump_compress status */
+ case DIOSDUMPCOMPRESS:
+ /* check flags */
+ if (!(f->f_flags & O_RDWR))
+ return (-EPERM);
+
+ return (dump_compress_init((int)arg));
+
+ /* get the dump_compress status */
+ case DIOGDUMPCOMPRESS:
+ return (put_user((long)dump_compress, (long *)arg));
+
+ }
+ return (0);
+}
+
+/*
+ * Name: dump_open()
+ * Func: Open the dump device for use when the system crashes.
+ */
+static int
+dump_open(struct inode *i, struct file *f)
+{
+ /* opening a device is straightforward -- nothing to do here */
+ return (0);
+}
+
+/*
+ * -----------------------------------------------------------------------
+ * I N I T F U N C T I O N S
+ * -----------------------------------------------------------------------
+ */
+
+/*
+ * Name: dump_init_proc_entry()
+ * Func: Create a dump proc entry based on the /proc dump root.
+ * Returns 1 on failure, 0 on success.
+ */
+int
+dump_init_proc_entry(char *name, struct proc_dir_entry *dirent)
+{
+ if (!(dirent = create_proc_entry(name,
+ S_IFREG|S_IRUGO|S_IWUSR, dump_root))) {
+ DUMP_PRINT("unable to initialize "
+ "/proc/%s/%s!\n", DUMP_ROOT_NAME, name);
+ return (1);
+ }
+ dirent->data = (void *)dirent;
+ dirent->read_proc = &dump_read_proc;
+ dirent->write_proc = NULL;
+ dirent->size = 16;
+ return (0);
+}
+
+/*
+ * Name: dump_proc_init()
+ * Func: Initialize the /proc interfaces for dumping.
+ *
+ * Typically:
+ * /proc/sys/dump/
+ * dump_compress dump_device dump_flags dump_level
+ */
+int
+dump_proc_init(void)
+{
+ /* create the proc entries for the various tunables */
+ dump_root = create_proc_entry(DUMP_ROOT_NAME, S_IFDIR, 0);
+ if (dump_root) {
+ dump_root->owner = THIS_MODULE;
+ } else {
+ DUMP_PRINTF("unable to initialize /proc/%s!\n", DUMP_ROOT_NAME);
+ return (-EBUSY);
+ }
+
+ if (dump_init_proc_entry(DUMP_DEVICE_NAME, dump_dd)) {
+ remove_proc_entry(DUMP_ROOT_NAME, 0);
+ return (-EBUSY);
+ }
+ if (dump_init_proc_entry(DUMP_LEVEL_NAME, dump_l)) {
+ remove_proc_entry(DUMP_ROOT_NAME, 0);
+ remove_proc_entry(DUMP_DEVICE_NAME, dump_root);
+ return (-EBUSY);
+ }
+ if (dump_init_proc_entry(DUMP_FLAGS_NAME, dump_f)) {
+ remove_proc_entry(DUMP_ROOT_NAME, 0);
+ remove_proc_entry(DUMP_DEVICE_NAME, dump_root);
+ remove_proc_entry(DUMP_LEVEL_NAME, dump_root);
+ return (-EBUSY);
+ }
+ if (dump_init_proc_entry(DUMP_COMPRESS_NAME, dump_cp)) {
+ remove_proc_entry(DUMP_ROOT_NAME, 0);
+ remove_proc_entry(DUMP_DEVICE_NAME, dump_root);
+ remove_proc_entry(DUMP_LEVEL_NAME, dump_root);
+ remove_proc_entry(DUMP_FLAGS_NAME, dump_root);
+ return (-EBUSY);
+ }
+ return (0);
+}
+
+/*
+ * Name: dump_proc_cleanup()
+ * Func: Cleanup the /proc interfaces for dumping.
+ */
+void
+dump_proc_cleanup(void)
+{
+ /* remove the proc entries */
+ remove_proc_entry(DUMP_DEVICE_NAME, dump_root);
+ remove_proc_entry(DUMP_LEVEL_NAME, dump_root);
+ remove_proc_entry(DUMP_FLAGS_NAME, dump_root);
+ remove_proc_entry(DUMP_COMPRESS_NAME, dump_root);
+ remove_proc_entry(DUMP_ROOT_NAME, 0);
+ return;
+}
+
+/*
+ * These register and unregister routines are exported for modules
+ * to register their dump drivers (like block, net etc)
+ */
+int
+dump_register_device(struct dump_operations *dump_ops)
+{
+ if (dump_device_ops)
+ return (-1);
+ dump_device_ops = dump_ops;
+ return (0);
+}
+
+void
+dump_unregister_device(void)
+{
+ dump_device_ops = 0;
+}
+
+/*
+ * Name: dump_init()
+ * Func: Initialize the dump process. This will set up any architecture
+ * dependent code. The big key is we need the memory offsets before
+ * the page table is initialized, because the base memory offset
+ * is changed after paging_init() is called.
+ */
+int __init
+dump_init(void)
+{
+ struct sysinfo info;
+ int i;
+
+ /* try to initialize /proc interfaces */
+ if (dump_proc_init() < 0) {
+ DUMP_PRINTF("dump_proc_init failed!; dump not initialized\n");
+ return (-EBUSY);
+ }
+
+ /* try to create our dump device */
+ if (register_chrdev(DUMP_MAJOR, "dump", &dump_fops)) {
+ DUMP_PRINTF("cannot register dump character device!\n");
+ return (-EBUSY);
+ }
+
+ /* initialize the dump headers to zero */
+ memset(&dump_header, 0, sizeof(dump_header));
+ memset(&dump_header_asm, 0, sizeof(dump_header_asm));
+
+#if !defined(CONFIG_DISCONTIGMEM) && !defined(CONFIG_IA64)
+ /*
+ * CONFIG_DISCONTIGMEM and CONFIG_IA64 systems are responsible
+ * for initializing dump_mbank[] in __dump_init().
+ */
+ dump_mbanks = 1;
+ dump_mbank[0].start = 0;
+ dump_mbank[0].end = (((u64) max_mapnr) << PAGE_SHIFT) - 1;
+ dump_mbank[0].type = DUMP_MBANK_TYPE_CONVENTIONAL_MEMORY;
+#endif
+
+ /*
+ * initialize the dump device at the arch level.
+ *
+ * if defined(CONFIG_DISCONTIGMEM) {
+ * __dump_init() must set up dump_mbank[].
+ * }
+ */
+ __dump_init((u64)PAGE_OFFSET);
+
+ /* initialize the dump page buffer */
+ dump_page_buf = (void *)0;
+
+ /* set the dump function pointer for dump execution */
+ dump_function_ptr = dump_execute;
+
+ /* set the dump_compression_list structure up */
+ dump_compress = DUMP_COMPRESS_NONE;
+ dump_compress_func = dump_compress_none;
+ dump_register_compression(&dump_none_compression);
+
+ /* initialize the dump flags, dump level and dump_compress fields */
+ dump_flags = DUMP_FLAGS_NONE;
+ dump_level = DUMP_LEVEL_ALL;
+
+ /* grab the total memory size now (not if/when we crash) */
+ si_meminfo(&info);
+
+ /* set the memory size */
+ dump_header.dh_memory_size = (u64)info.totalram;
+
+ for (i = 0; i < dump_mbanks; i++) {
+ DUMP_PRINTF("mbank[%d]: type:%d, phys_addr" PU64X " ... "
+ PU64X "\n" ,i, dump_mbank[i].type, dump_mbank[i].start,
+ dump_mbank[i].end);
+ if (dump_mbank[i].start % DUMP_PAGE_SIZE)
+ DUMP_PRINTF("oops, start is not DUMP_PAGE_SIZE:%x "
+ "aligned!\n", (int) DUMP_PAGE_SIZE);
+
+ if ((dump_mbank[i].end + 1) % DUMP_PAGE_SIZE)
+ DUMP_PRINTF("oops, end is not DUMP_PAGE_SIZE:%x "
+ "aligned!\n", (int) DUMP_PAGE_SIZE);
+ }
+ DUMP_PRINTF("Crash dump driver initialized.\n");
+ return (0);
+}
+
+void __exit
+dump_cleanup(void)
+{
+ /* get rid of the allocated dump page buffer */
+ if (dump_page_buf_0)
+ kfree((const void *)dump_page_buf_0);
+
+ /* arch-specific cleanup routine */
+ __dump_cleanup();
+
+ /* remove the proc entries */
+ dump_proc_cleanup();
+
+ /* try to create our dump device */
+ if (unregister_chrdev(DUMP_MAJOR, "dump"))
+ DUMP_PRINT("cannot unregister dump character device!\n");
+
+ /* reset the dump function pointer */
+ dump_function_ptr = NULL;
+
+ return;
+}
+
+EXPORT_SYMBOL(dump_register_compression);
+EXPORT_SYMBOL(dump_unregister_compression);
+EXPORT_SYMBOL(dump_register_device);
+EXPORT_SYMBOL(dump_unregister_device);
+
+#ifdef MODULE
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,4,16))
+#if !defined(MODULE_LICENSE)
+#define MODULE_LICENSE(str)
+#endif
+#endif
+
+MODULE_AUTHOR("Matt D. Robinson <yakker@sourceforge.net>");
+MODULE_DESCRIPTION("Linux Kernel Crash Dump (LKCD) driver");
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,16))
+MODULE_LICENSE("GPL");
+#endif
+#endif /* MODULE */
+
+module_init(dump_init);
+module_exit(dump_cleanup);
diff -Naur linux-2.5.44.orig/drivers/dump/dump_blockdev.c linux-2.5.44.lkcd/drivers/dump/dump_blockdev.c
--- linux-2.5.44.orig/drivers/dump/dump_blockdev.c Wed Dec 31 16:00:00 1969
+++ linux-2.5.44.lkcd/drivers/dump/dump_blockdev.c Sat Oct 19 12:39:15 2002
@@ -0,0 +1,392 @@
+/*
+ * Block device driver for LKCD
+ * This code is released under version 2 of the GNU GPL.
+ */
+
+#include <linux/types.h>
+#include <linux/dump.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+
+#define DUMP_MODULE_NAME "dump_blockdev"
+
+/*
+ * -----------------------------------------------------------------------
+ * V A R I A B L E S
+ * -----------------------------------------------------------------------
+ */
+kdev_t dump_dev; /* the actual kdev_t device number */
+void *dump_page_buffer; /* dump page buffer for memcpy()! */
+int dump_blk_size; /* sector size for dump_device */
+int dump_blk_shift; /* shift need to convert to sector size */
+struct bio *dump_bio; /* bio structure for io request */
+loff_t dump_offset; /* the offset in the output device */
+struct block_device *dump_bdev = NULL;
+unsigned long dumpdev_limit; /* the size limit of the block device */
+volatile int bio_complete = 1;/* Indicates the completion of each bio request */
+int dump_io_abort = 0; /* set by end_io routine during io error */
+
+static void
+dump_free_bio(void)
+{
+ if (dump_bio && dump_bio->bi_io_vec)
+ kfree(dump_bio->bi_io_vec);
+ if (dump_bio)
+ kfree(dump_bio);
+}
+
+int
+dump_bio_end_io(struct bio *bio, unsigned int bytes_done, int error)
+{
+ /* No wakeup needed since we've stopped scheduling */
+ /* TODO: take care of the case when scheduler is enabled */
+
+ /*
+ * IO is not fully complete, return without setting bio_complete
+ * so that caller continues to wait for completion.
+ */
+ if (bio->bi_size)
+ return 1;
+
+ if (error) {
+ DUMP_PRINT("IO error while writing the dump, aborting\n");
+ dump_io_abort = 1;
+ }
+ bio_complete = 1;
+ clear_bit(BIO_UPTODATE, &dump_bio->bi_flags);
+
+ return 0;
+}
+
+/*
+ * Name: dump_open_kdev()
+ * Func: Try to open the kdev_t argument as the real dump device.
+ * This is where all the work is done for setting up the dump
+ * device. It's assumed at this point that by passing in the
+ * dump device's major/minor number, we can open it up, check
+ * it out, and use it for whatever purposes.
+ */
+static int
+dump_open_kdev(kdev_t tmp_dump_device)
+{
+ int i, retval = 0;
+ unsigned long a;
+ struct bio_vec *bvec;
+
+ /* make sure this is a valid block device */
+ if (!kdev_val(tmp_dump_device)) {
+ retval = -EINVAL;
+ goto err;
+ }
+
+ /* release earlier dump_bdev if present */
+ if (dump_bdev) {
+ blkdev_put(dump_bdev, BDEV_RAW);
+ dump_bdev = NULL;
+ }
+
+ dump_bdev = bdget(kdev_t_to_nr(tmp_dump_device));
+ if (!dump_bdev) {
+ retval = -ENODEV;
+ goto err;
+ }
+
+ if (blkdev_get(dump_bdev, O_RDWR | O_LARGEFILE, 0, BDEV_RAW)) {
+ retval = -ENODEV;
+ goto err1;
+ }
+
+ if ((dump_page_buffer== (void *)NULL)) {
+ retval = -EINVAL;
+ goto err2;
+ }
+
+ if (dump_bio)
+ dump_free_bio();
+
+ if ((dump_bio = kmalloc(sizeof(struct bio), GFP_KERNEL)) == NULL) {
+ DUMP_PRINTF("Cannot allocate bio\n");
+ retval = -ENOMEM;
+ goto err2;
+ }
+
+ bio_init(dump_bio);
+
+ if ((bvec = kmalloc(sizeof(struct bio_vec) *
+ (DUMP_BUFFER_SIZE >> PAGE_SHIFT), GFP_KERNEL)) == NULL) {
+ retval = -ENOMEM;
+ goto err3;
+ }
+
+ /* setup bio structure */
+ dump_bio->bi_io_vec = bvec;
+
+ a = (unsigned long) dump_page_buffer;
+ for (i = 0; i < (DUMP_BUFFER_SIZE >> PAGE_SHIFT); i++, bvec++,
+ a += PAGE_SIZE) {
+ dump_bio->bi_vcnt++;
+ bvec->bv_page = (struct page *)virt_to_page(a);
+ bvec->bv_len = PAGE_SIZE;
+ bvec->bv_offset = 0;
+ }
+ dump_bio->bi_size = DUMP_BUFFER_SIZE;
+ dump_bio->bi_end_io = dump_bio_end_io;
+ dump_bio->bi_bdev = dump_bdev;
+
+ /* assign the new dump file structure */
+ dump_dev = tmp_dump_device;
+
+ /* note the max size of the dump device */
+ dumpdev_limit = dump_bdev->bd_inode->i_size;
+
+ DUMP_PRINTN("dump device 0x%x opened; Ready to take a "
+ "core dump\n", kdev_val(dump_dev));
+
+ /* after opening the block device, return */
+ return 0;
+
+err3: dump_free_bio();
+err2: if (dump_bdev) {
+ blkdev_put(dump_bdev, BDEV_RAW);
+ dump_bdev = NULL;
+ }
+err1: if (dump_bdev) {
+ bdput(dump_bdev);
+ dump_bdev = NULL;
+ }
+err: return retval;
+}
+
+/*
+ * Name: dev_dump_release()
+ * Func: Release the dump device -- it's never necessary to call
+ * this function, but it's here regardless.
+ */
+static int
+dev_dump_release(void)
+{
+ return (0);
+}
+
+/*
+ * Name: dev_dump_end()
+ * Func: end the dump device -- it's never necessary to call
+ * this function, but it's here regardless.
+ */
+static int
+dev_dump_end(unsigned long arg)
+{
+ return (0);
+}
+
+/*
+ * Name: dev_dump_ioctl()
+ * Func: Allow all dump tunables through a standard ioctl() mechanism.
+ * This is far better than before, where we'd go through /proc,
+ * because now this will work for multiple OS and architectures.
+ */
+static int
+dev_dump_ioctl(unsigned int cmd, unsigned long arg)
+{
+ int ret = 0;
+
+ /*
+ * This is the main mechanism for controlling get/set data
+ * for various dump device parameters. The real trick here
+ * is setting the dump device (DIOSDUMPDEV). That's what
+ * triggers everything else.
+ */
+ switch (cmd) {
+ case DIOSDUMPDEV:
+ ret = dump_open_kdev(to_kdev_t((dev_t)arg));
+ break;
+ case DIOSDUMPMEM:
+ dump_page_buffer = (void *)arg;
+ break;
+ default:
+ break;
+
+ }
+ return (ret);
+}
+
+/*
+ * Name: dev_dump_seek()
+ * Func: seek to the dump device for use when the system crashes.
+ */
+static loff_t
+dev_dump_seek(loff_t off, int tmp)
+{
+ if (off & (PAGE_SIZE - 1)) {
+ DUMP_PRINT("seek, non-aligned page\n");
+ return (-EINVAL);
+ }
+
+ if (off & (bdev_hardsect_size(dump_bio->bi_bdev) - 1)) {
+ DUMP_PRINT("seek, sector not aligned\n");
+ return (-EINVAL);
+ }
+
+ if (off > dumpdev_limit) {
+ DUMP_PRINT("seek, not enough space left on device!\n");
+ return (-ENOSPC);
+ }
+ dump_offset = off;
+ return (0);
+}
+
+/*
+ * Name: dev_dump_write()
+ *
+ * Func: Write out kernel information, check the device limitations etc
+ * Writes DUMP_BUFFER_SIZE bytes in page buffer
+ *
+ * Returns: number of bytes written or -ERRNO.
+ * At EOF it returns 0.
+ */
+static ssize_t
+dev_dump_write(const char *buff, size_t len, loff_t *offset)
+{
+ /* this condition will not be true for now */
+ if (len > DUMP_BUFFER_SIZE) {
+ DUMP_PRINTN("max dump buffer size exceeded");
+ return (-EINVAL);
+ }
+
+ if (dump_offset >= dumpdev_limit) {
+ DUMP_PRINTN("no space left on device!");
+ return (-ENOSPC);
+ }
+
+ /*
+ * If near the end of the dump device we set *eof (if ptr provided) to
+ * let the caller know that it's near the EOF on the dump device.
+ */
+ if ((dump_offset + (4 * DUMP_BUFFER_SIZE)) > dumpdev_limit) {
+ if (offset != NULL) *offset = 1;
+ DUMP_BP();
+ }
+
+ if (dump_offset + len > dumpdev_limit)
+ len = dumpdev_limit - dump_offset;
+
+ /* make sure we have space to write! */
+ if (!len) {
+ DUMP_PRINTN("no space left on dump device!");
+ return (0);
+ }
+
+ /* re-initialize the fields of bio structure */
+ dump_bio->bi_sector = dump_offset >> 9;
+ dump_bio->bi_bdev = dump_bdev;
+ dump_bio->bi_vcnt = len >> PAGE_SHIFT;
+ dump_bio->bi_idx = 0;
+ dump_bio->bi_size = len;
+
+ /*
+ * write out the data to disk.
+ * here we submit a bio request for size = 64k(DUMP_BUFFER_SIZE)
+ * and wait for io completion. In future, we can think of increasing
+ * the dump buffer size and issuing multiple bios parallelly.
+ */
+ bio_complete = 0;
+ submit_bio(WRITE, dump_bio);
+
+ return len;
+}
+
+/*
+ * Name: dev_dump_open()
+ * Func: Open the dump device for use when the system crashes.
+ */
+static int
+dev_dump_open(void)
+{
+ return (0);
+}
+
+/*
+ * Name: dev_dump_start()
+ * Func: start the dump device for use when the system crashes.
+ */
+static int
+dev_dump_start(unsigned long arg)
+{
+ return (0);
+}
+
+/*
+ * Name: dev_dump_ready()
+ * Func: check the dump device for use when the system crashes.
+ */
+static int
+dev_dump_ready(unsigned long arg)
+{
+ request_queue_t *q = bdev_get_queue(dump_bio->bi_bdev);
+
+ /* wait for io completion */
+ while (!bio_complete)
+ q->unplug_fn(q);
+
+ if (dump_io_abort)
+ return (-EIO);
+ return (1);
+}
+
+static struct dump_operations dump_blockdev_ops = {
+ dump_open: dev_dump_open,
+ dump_release: dev_dump_release,
+ dump_ioctl: dev_dump_ioctl,
+ dump_write: dev_dump_write,
+ dump_seek: dev_dump_seek,
+ dump_start: dev_dump_start,
+ dump_end: dev_dump_end,
+ dump_ready: dev_dump_ready,
+};
+
+int __init
+dump_blockdev_init(void)
+{
+ dump_page_buffer = NULL;
+ dump_offset = 0;
+
+ if (dump_register_device(&dump_blockdev_ops) < 0) {
+ DUMP_PRINTN("block device driver registration failed\n");
+ return (-1);
+ }
+
+ DUMP_PRINTN("block device driver for LKCD unregistered\n");
+ return (0);
+}
+
+void __exit
+dump_blockdev_cleanup(void)
+{
+ dump_unregister_device();
+ DUMP_PRINTN("block device driver for LKCD unregistered\n");
+ if (dump_bdev) {
+ blkdev_put(dump_bdev, BDEV_RAW);
+ dump_bdev = NULL;
+ }
+ if (dump_bio)
+ dump_free_bio();
+}
+
+#ifdef MODULE
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,4,16))
+#if !defined(MODULE_LICENSE)
+#define MODULE_LICENSE(str)
+#endif
+#endif
+
+MODULE_AUTHOR("Mohamed. Abbas");
+MODULE_DESCRIPTION("Block Device Driver for Linux Kernel Crash Dump (LKCD)");
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,16))
+MODULE_LICENSE("GPL");
+#endif
+#endif /* MODULE */
+module_init(dump_blockdev_init);
+module_exit(dump_blockdev_cleanup);
diff -Naur linux-2.5.44.orig/drivers/dump/dump_i386.c linux-2.5.44.lkcd/drivers/dump/dump_i386.c
--- linux-2.5.44.orig/drivers/dump/dump_i386.c Wed Dec 31 16:00:00 1969
+++ linux-2.5.44.lkcd/drivers/dump/dump_i386.c Sat Oct 19 12:39:15 2002
@@ -0,0 +1,315 @@
+/*
+ * Architecture specific (i386) functions for Linux crash dumps.
+ *
+ * Created by: Matt Robinson (yakker@sgi.com)
+ *
+ * Copyright 1999 Silicon Graphics, Inc. All rights reserved.
+ *
+ * 2.3 kernel modifications by: Matt D. Robinson (yakker@turbolinux.com)
+ * Copyright 2000 TurboLinux, Inc. All rights reserved.
+ *
+ * This code is released under version 2 of the GNU GPL.
+ */
+
+/*
+ * The hooks for dumping the kernel virtual memory to disk are in this
+ * file. Any time a modification is made to the virtual memory mechanism,
+ * these routines must be changed to use the new mechanisms.
+ */
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/smp.h>
+#include <linux/fs.h>
+#include <linux/vmalloc.h>
+#include <linux/dump.h>
+#include <linux/mm.h>
+#include <linux/irq.h>
+
+#include <asm/processor.h>
+#include <asm/hardirq.h>
+
+static int alloc_dha_stack(void)
+{
+ int i;
+ void *ptr;
+
+ if (dump_header_asm.dha_stack[0])
+ return 0;
+
+ ptr = vmalloc(THREAD_SIZE * num_online_cpus());
+ if (!ptr) {
+ printk("vmalloc for dha_stacks failed\n");
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < num_online_cpus(); i++) {
+ dump_header_asm.dha_stack[i] = (uint32_t)((unsigned long)ptr +
+ (i * THREAD_SIZE));
+ }
+ return 0;
+}
+
+static int free_dha_stack(void)
+{
+ if (dump_header_asm.dha_stack[0])
+ vfree((void *)dump_header_asm.dha_stack[0]);
+ return 0;
+}
+
+/* In case of panic dumps, we collects regs on entry to panic.
+ * so, we shouldn't 'fix' ssesp here again. But it is hard to
+ * tell just looking at regs whether ssesp need fixing. We make
+ * this decision by looking at xss in regs. If we have better
+ * means to determine that ssesp are valid (by some flag which
+ * tells that we are here due to panic dump), then we can use
+ * that instead of this kludge.
+ */
+static inline void
+fix_ssesp(struct pt_regs *regs, int cpu)
+{
+ if (!user_mode(regs)) {
+ if ((cpu == dump_header_asm.dha_dumping_cpu) &&
+ (0xffff & regs->xss) == __KERNEL_DS)
+ return;
+ dump_header_asm.dha_smp_regs[cpu].esp =
+ (unsigned long)&(regs->esp);
+ __asm__ __volatile__ ("movw %%ss, %%ax;"
+ :"=a"(dump_header_asm.dha_smp_regs[cpu].xss));
+ }
+}
+
+static void
+save_this_cpu_state(int cpu, struct pt_regs *regs, struct task_struct *tsk)
+{
+ dump_header_asm.dha_smp_regs[cpu] = *regs;
+ dump_header_asm.dha_smp_current_task[cpu] = (uint32_t)tsk;
+ fix_ssesp(regs, cpu);
+
+ if (dump_header_asm.dha_stack[cpu]) {
+ memcpy((void *)dump_header_asm.dha_stack[cpu],
+ tsk->thread_info, THREAD_SIZE);
+ }
+ dump_header_asm.dha_stack_ptr[cpu] = (uint32_t)(tsk->thread_info);
+ return;
+}
+
+#ifdef CONFIG_SMP
+extern irq_desc_t irq_desc[];
+extern unsigned long irq_affinity[];
+extern void dump_send_ipi(void);
+static int dump_expect_ipi[NR_CPUS];
+static atomic_t waiting_for_dump_ipi;
+static int wait_for_dump_ipi = 1; /* always wait for ipi to to be handled */
+extern void (*dump_trace_ptr)(struct pt_regs *);
+static unsigned long saved_affinity[NR_IRQS];
+__s32 saved_irq_count, saved_bh_count;
+
+static int
+dump_ipi_handler(struct pt_regs *regs)
+{
+ int cpu = smp_processor_id();
+
+ if (!dump_expect_ipi[cpu]) {
+ return 0;
+ }
+
+ save_this_cpu_state(cpu, regs, current);
+
+ dump_expect_ipi[cpu] = 0;
+ atomic_dec(&waiting_for_dump_ipi);
+
+ /* Mark the task for rescheduling, so that it task spins in schedule */
+ set_tsk_thread_flag(current, TIF_NEED_RESCHED);
+
+ return 1;
+}
+
+/* save registers on other processors */
+void
+save_other_cpu_states(void)
+{
+ int i;
+
+ if (num_online_cpus() > 1) {
+ atomic_set(&waiting_for_dump_ipi, num_online_cpus()-1);
+ for (i = 0; i < NR_CPUS; i++)
+ dump_expect_ipi[i] = 1;
+
+ dump_ipi_function_ptr = dump_ipi_handler;
+ dump_send_ipi();
+ /* may be we dont need to wait for NMI to be processed.
+ just write out the header at the end of dumping, if
+ this IPI is not processed untill then, there probably
+ is a problem and we just fail to capture state of
+ other cpus. */
+ if (wait_for_dump_ipi) {
+ while(atomic_read(&waiting_for_dump_ipi))
+ barrier();
+ dump_ipi_function_ptr = NULL;
+ }
+ }
+ return;
+}
+
+/*
+ * Routine to save the old irq affinities and change affinities of all irqs to
+ * the dumping cpu.
+ */
+static void
+__dump_set_irq_affinity(void)
+{
+ int i;
+ int cpu = smp_processor_id();
+
+ memcpy(saved_affinity, irq_affinity, NR_IRQS * sizeof(unsigned long));
+ for (i = 0; i < NR_IRQS; i++) {
+ if (irq_desc[i].handler == NULL)
+ continue;
+ irq_affinity[i] = 1UL << cpu;
+ if (irq_desc[i].handler->set_affinity != NULL)
+ irq_desc[i].handler->set_affinity(i, irq_affinity[i]);
+ }
+}
+
+/*
+ * Restore old irq affinities.
+ */
+static void
+__dump_reset_irq_affinity(void)
+{
+ int i;
+
+ memcpy(irq_affinity, saved_affinity, NR_IRQS * sizeof(unsigned long));
+ for (i = 0; i < NR_IRQS; i++) {
+ if (irq_desc[i].handler == NULL)
+ continue;
+ if (irq_desc[i].handler->set_affinity != NULL)
+ irq_desc[i].handler->set_affinity(i, saved_affinity[i]);
+ }
+}
+
+/*
+ * Kludge - dump from interrupt context is unreliable (Fixme)
+ *
+ * We do this so that softirqs initiated for dump i/o
+ * get processed and we don't hang while waiting for i/o
+ * to complete or in any irq synchronization attempt.
+ *
+ * This is not quite legal of course, as it has the side
+ * effect of making all interrupts & softirqs triggered
+ * while dump is in progress complete before currently
+ * pending softirqs and the currently executing interrupt
+ * code.
+ */
+static inline void irq_bh_save(void)
+{
+ saved_irq_count = hardirq_count();
+ saved_bh_count = softirq_count();
+ preempt_count() &= ~HARDIRQ_MASK;
+ preempt_count() &= ~SOFTIRQ_MASK;
+}
+
+static inline void irq_bh_restore(void)
+{
+ preempt_count() |= saved_irq_count;
+ preempt_count() |= saved_bh_count;
+}
+
+#else /* !CONFIG_SMP */
+#define save_other_cpu_states()
+#endif /* !CONFIG_SMP */
+
+/*
+ * Name: __dump_silence_system()
+ * Func: Do an architecture-specific silencing of the system.
+ * - Change irq affinities
+ * - Wait for other cpus to come out of irq handling
+ * - Send CALL_FUNCTION_VECTOR ipi to other cpus to put them to spin
+ */
+unsigned int
+__dump_silence_system(unsigned int stage)
+{
+#ifdef CONFIG_SMP
+ if (stage) { /* Do this after interrupts are enabled */
+ __dump_set_irq_affinity();
+ irq_bh_save();
+ /* synchronize_irq(); TODO: needed ? */
+ }
+#endif
+ /* return */
+ return (0);
+}
+
+/*
+ * Name: __dump_resume_system()
+ * Func: Resume the system state in an architecture-specific way.
+ */
+unsigned int
+__dump_resume_system(unsigned int stage)
+{
+#ifdef CONFIG_SMP
+ /* put the irq affinity tables back */
+ __dump_reset_irq_affinity();
+ irq_bh_restore();
+#endif
+ /* return */
+ return (0);
+}
+
+/*
+ * Name: __dump_configure_header()
+ * Func: Configure the dump header with all proper values.
+ */
+int
+__dump_configure_header(struct pt_regs *regs)
+{
+ int cpu = smp_processor_id();
+
+ dump_header_asm.dha_smp_num_cpus = num_online_cpus();
+ dump_header_asm.dha_dumping_cpu = cpu;
+
+ save_this_cpu_state(cpu, regs, current);
+
+ save_other_cpu_states();
+
+ return (1);
+}
+
+/*
+ * Name: __dump_init()
+ * Func: Initialize the dumping routine process. This is in case
+ * it's necessary in the future.
+ */
+void __init
+__dump_init(uint64_t local_memory_start)
+{
+ /* return */
+ return;
+}
+
+/*
+ * Name: __dump_open()
+ * Func: Open the dump device (architecture specific). This is in
+ * case it's necessary in the future.
+ */
+void
+__dump_open(void)
+{
+ alloc_dha_stack();
+ /* return */
+ return;
+}
+
+/*
+ * Name: __dump_cleanup()
+ * Func: Free any architecture specific data structures. This is called
+ * when the dump module is being removed.
+ */
+void __exit
+__dump_cleanup(void)
+{
+ free_dha_stack();
+ /* return */
+ return;
+}
diff -Naur linux-2.5.44.orig/include/asm-i386/dump.h linux-2.5.44.lkcd/include/asm-i386/dump.h
--- linux-2.5.44.orig/include/asm-i386/dump.h Wed Dec 31 16:00:00 1969
+++ linux-2.5.44.lkcd/include/asm-i386/dump.h Sat Oct 19 12:39:15 2002
@@ -0,0 +1,94 @@
+/*
+ * Kernel header file for Linux crash dumps.
+ *
+ * Created by: Matt Robinson (yakker@sgi.com)
+ *
+ * Copyright 1999 Silicon Graphics, Inc. All rights reserved.
+ *
+ * This code is released under version 2 of the GNU GPL.
+ */
+
+/* This header file holds the architecture specific crash dump header */
+#ifndef _ASM_DUMP_H
+#define _ASM_DUMP_H
+
+/* necessary header files */
+#include <asm/ptrace.h> /* for pt_regs */
+#include <linux/threads.h>
+
+/* definitions */
+#define DUMP_ASM_MAGIC_NUMBER 0xdeaddeadULL /* magic number */
+#define DUMP_ASM_VERSION_NUMBER 0x3 /* version number */
+
+/* max number of cpus */
+#define DUMP_MAX_NUM_CPUS 32
+
+/*
+ * Structure: dump_header_asm_t
+ * Function: This is the header for architecture-specific stuff. It
+ * follows right after the dump header.
+ */
+typedef struct _dump_header_asm_s {
+
+ /* the dump magic number -- unique to verify dump is valid */
+ uint64_t dha_magic_number;
+
+ /* the version number of this dump */
+ uint32_t dha_version;
+
+ /* the size of this header (in case we can't read it) */
+ uint32_t dha_header_size;
+
+ /* the esp for i386 systems */
+ uint32_t dha_esp;
+
+ /* the eip for i386 systems */
+ uint32_t dha_eip;
+
+ /* the dump registers */
+ struct pt_regs dha_regs;
+
+ /* smp specific */
+ uint32_t dha_smp_num_cpus;
+ uint32_t dha_dumping_cpu;
+ struct pt_regs dha_smp_regs[DUMP_MAX_NUM_CPUS];
+ uint32_t dha_smp_current_task[DUMP_MAX_NUM_CPUS];
+ uint32_t dha_stack[DUMP_MAX_NUM_CPUS];
+ uint32_t dha_stack_ptr[DUMP_MAX_NUM_CPUS];
+} __attribute__((packed)) dump_header_asm_t;
+
+#ifdef __KERNEL__
+static inline void get_current_regs(struct pt_regs *regs)
+{
+ __asm__ __volatile__("movl %%ebx,%0" : "=m"(regs->ebx));
+ __asm__ __volatile__("movl %%ecx,%0" : "=m"(regs->ecx));
+ __asm__ __volatile__("movl %%edx,%0" : "=m"(regs->edx));
+ __asm__ __volatile__("movl %%esi,%0" : "=m"(regs->esi));
+ __asm__ __volatile__("movl %%edi,%0" : "=m"(regs->edi));
+ __asm__ __volatile__("movl %%ebp,%0" : "=m"(regs->ebp));
+ __asm__ __volatile__("movl %%eax,%0" : "=m"(regs->eax));
+ __asm__ __volatile__("movl %%esp,%0" : "=m"(regs->esp));
+ __asm__ __volatile__("movw %%ss, %%ax;" :"=a"(regs->xss));
+ __asm__ __volatile__("movw %%cs, %%ax;" :"=a"(regs->xcs));
+ __asm__ __volatile__("movw %%ds, %%ax;" :"=a"(regs->xds));
+ __asm__ __volatile__("movw %%es, %%ax;" :"=a"(regs->xes));
+ __asm__ __volatile__("pushfl; popl %0" :"=m"(regs->eflags));
+ regs->eip = (unsigned long)current_text_addr();
+
+}
+
+extern volatile int dump_in_progress;
+extern unsigned long irq_affinity[];
+extern dump_header_asm_t dump_header_asm;
+
+#ifdef CONFIG_SMP
+extern int (*dump_ipi_function_ptr)(struct pt_regs *);
+extern void dump_send_ipi(void);
+#else
+#define dump_send_ipi()
+#endif
+
+
+#endif /* __KERNEL__ */
+
+#endif /* _ASM_DUMP_H */
diff -Naur linux-2.5.44.orig/include/linux/dump.h linux-2.5.44.lkcd/include/linux/dump.h
--- linux-2.5.44.orig/include/linux/dump.h Wed Dec 31 16:00:00 1969
+++ linux-2.5.44.lkcd/include/linux/dump.h Sat Oct 19 12:39:15 2002
@@ -0,0 +1,438 @@
+/*
+ * Kernel header file for Linux crash dumps.
+ *
+ * Created by: Matt Robinson (yakker@sgi.com)
+ * Copyright 1999 - 2002 Silicon Graphics, Inc. All rights reserved.
+ *
+ * vmdump.h to dump.h by: Matt D. Robinson (yakker@sourceforge.net)
+ * Copyright 2001 - 2002 Matt D. Robinson. All rights reserved.
+ * Copyright (C) 2002 Free Software Foundation, Inc. All rights reserved.
+ *
+ * Most of this is the same old stuff from vmdump.h, except now we're
+ * actually a stand-alone driver plugged into the block layer interface,
+ * with the exception that we now allow for compression modes externally
+ * loaded (e.g., someone can come up with their own).
+ *
+ * This code is released under version 2 of the GNU GPL.
+ */
+
+/* This header file includes all structure definitions for crash dumps. */
+#ifndef _DUMP_H
+#define _DUMP_H
+
+#include <linux/list.h>
+#include <linux/notifier.h>
+
+/* define TRUE and FALSE for use in our dump modules */
+#ifndef FALSE
+#define FALSE 0
+#endif
+
+#ifndef TRUE
+#define TRUE 1
+#endif
+
+
+/*
+ * DUMP_DEBUG: a debug level for the kernel dump code and
+ * the supporting lkcd libraries in user space.
+ *
+ * 0: FALSE: No Debug Added
+ * 1: TRUE: Break Points
+ * .
+ * .
+ * .
+ * 6: Add Debug Data to Structures
+ * .
+ * .
+ * 9: Max
+ */
+#define DUMP_DEBUG FALSE
+
+#if DUMP_DEBUG
+void dump_bp(void); /* Called when something exceptional occurs */
+#define DUMP_BP() dump_bp() /* Breakpoint */
+#else
+#define DUMP_BP()
+#endif
+
+/*
+ * Predefine default DUMP_PAGE constants, asm header may override.
+ *
+ * On ia64 discontinuous memory systems it's possible for the memory
+ * banks to stop at 2**12 page alignments, the smallest possible page
+ * size. But the system page size, PAGE_SIZE, is in fact larger.
+ */
+#define DUMP_PAGE_SHIFT PAGE_SHIFT
+#define DUMP_PAGE_MASK PAGE_MASK
+#define DUMP_PAGE_ALIGN(addr) PAGE_ALIGN(addr)
+#define DUMP_HEADER_OFFSET PAGE_SIZE
+
+/* keep DUMP_PAGE_SIZE constant to 4K = 1<<12
+ * it may be different from PAGE_SIZE then.
+ */
+#define DUMP_PAGE_SIZE 4096
+
+/*
+ * Predefined default memcpy() to use when copying memory to the dump buffer.
+ *
+ * On ia64 there is a heads up function that can be called to let the prom
+ * machine check monitor know that the current activity is risky and it should
+ * ignore the fault (nofault). In this case the ia64 header will redefine this
+ * macro to __dump_memcpy() and use it's arch specific version.
+ */
+#define DUMP_memcpy memcpy
+
+
+/* necessary header files */
+#include <asm/dump.h> /* for architecture-specific header */
+
+/* necessary header definitions in all cases */
+#define DUMP_KIOBUF_NUMBER 0xdeadbeef /* special number for kiobuf maps */
+
+/*
+ * Size of the buffer that's used to hold:
+ *
+ * 1. the dump header (padded to fill the complete buffer)
+ * 2. the possibly compressed page headers and data
+ */
+#define DUMP_BUFFER_SIZE (64 * 1024) /* size of dump buffer (0x10000) */
+#define DUMP_HEADER_SIZE DUMP_BUFFER_SIZE
+
+/* header definitions for s390 dump */
+#define DUMP_MAGIC_S390 0xa8190173618f23fdULL /* s390 magic number */
+#define S390_DUMP_HEADER_SIZE 4096
+
+/* standard header definitions */
+#define DUMP_MAGIC_NUMBER 0xa8190173618f23edULL /* dump magic number */
+#define DUMP_MAGIC_LIVE 0xa8190173618f23cdULL /* live magic number */
+#define DUMP_VERSION_NUMBER 0x8 /* dump version number */
+#define DUMP_PANIC_LEN 0x100 /* dump panic string length */
+
+/* dump levels - type specific stuff added later -- add as necessary */
+#define DUMP_LEVEL_NONE 0x0 /* no dumping at all -- just bail */
+#define DUMP_LEVEL_HEADER 0x1 /* kernel dump header only */
+#define DUMP_LEVEL_KERN 0x2 /* dump header and kernel pages */
+#define DUMP_LEVEL_USED 0x4 /* dump header, kernel/user pages */
+#define DUMP_LEVEL_ALL_RAM 0x8 /* dump header, all RAM pages */
+#define DUMP_LEVEL_ALL 0x10 /* dump all memory RAM and firmware */
+
+
+/* dump compression options -- add as necessary */
+#define DUMP_COMPRESS_NONE 0x0 /* don't compress this dump */
+#define DUMP_COMPRESS_RLE 0x1 /* use RLE compression */
+#define DUMP_COMPRESS_GZIP 0x2 /* use GZIP compression */
+
+/* dump flags - any dump-type specific flags -- add as necessary */
+#define DUMP_FLAGS_NONE 0x0 /* no flags are set for this dump */
+#define DUMP_FLAGS_NONDISRUPT 0x1 /* try to keep running after dump */
+
+/* dump header flags -- add as necessary */
+#define DUMP_DH_FLAGS_NONE 0x0 /* no flags set (error condition!) */
+#define DUMP_DH_RAW 0x1 /* raw page (no compression) */
+#define DUMP_DH_COMPRESSED 0x2 /* page is compressed */
+#define DUMP_DH_END 0x4 /* end marker on a full dump */
+#define DUMP_DH_TRUNCATED 0x8 /* dump is incomplete */
+#define DUMP_DH_TEST_PATTERN 0x10 /* dump page is a test pattern */
+#define DUMP_DH_NOT_USED 0x20 /* 1st bit not used in flags */
+
+/* names for various dump tunables (they are now all read-only) */
+#define DUMP_ROOT_NAME "sys/dump"
+#define DUMP_DEVICE_NAME "dump_device"
+#define DUMP_COMPRESS_NAME "dump_compress"
+#define DUMP_LEVEL_NAME "dump_level"
+#define DUMP_FLAGS_NAME "dump_flags"
+
+/* page size for gzip compression -- buffered slightly beyond hardware PAGE_SIZE used by DUMP */
+#define DUMP_DPC_PAGE_SIZE (DUMP_PAGE_SIZE + 512)
+
+/* dump ioctl() control options */
+#define DIOSDUMPDEV 1 /* set the dump device */
+#define DIOGDUMPDEV 2 /* get the dump device */
+#define DIOSDUMPLEVEL 3 /* set the dump level */
+#define DIOGDUMPLEVEL 4 /* get the dump level */
+#define DIOSDUMPFLAGS 5 /* set the dump flag parameters */
+#define DIOGDUMPFLAGS 6 /* get the dump flag parameters */
+#define DIOSDUMPCOMPRESS 7 /* set the dump compress level */
+#define DIOGDUMPCOMPRESS 8 /* get the dump compress level */
+#define DIOSDUMPMEM 9 /* set the dump buffer memory */
+#define DUMPCONSOLE_MAJOR 245
+#define DUMPCONSOLE_NAME "netconsole"
+
+struct dump_operations {
+ loff_t (*dump_seek) (loff_t, int);
+ ssize_t (*dump_write) (const char *, size_t, loff_t *);
+ int (*dump_ioctl) (unsigned int, unsigned long);
+ int (*dump_open) (void);
+ int (*dump_release) (void);
+ int (*dump_start) (unsigned long);
+ int (*dump_end) (unsigned long);
+ int (*dump_ready) (unsigned long);
+};
+
+extern int dump_register_device(struct dump_operations *);
+extern void dump_unregister_device(void);
+
+/* the major number used for the dumping device */
+#ifndef DUMP_MAJOR
+#define DUMP_MAJOR 227
+#endif
+
+/*
+ * Structure: dump_header_t
+ * Function: This is the header dumped at the top of every valid crash
+ * dump.
+ * easy reassembly of each crash dump page. The address bits
+ * are split to make things easier for 64-bit/32-bit system
+ * conversions.
+ */
+typedef struct _dump_header_s {
+ /* the dump magic number -- unique to verify dump is valid */
+ uint64_t dh_magic_number;
+
+ /* the version number of this dump */
+ uint32_t dh_version;
+
+ /* the size of this header (in case we can't read it) */
+ uint32_t dh_header_size;
+
+ /* the level of this dump (just a header?) */
+ uint32_t dh_dump_level;
+
+ /*
+ * We assume dump_page_size to be 4K in every case.
+ * Store here the configurable system page size (4K, 8K, 16K, etc.)
+ */
+ uint32_t dh_page_size;
+
+ /* the size of all physical memory */
+ uint64_t dh_memory_size;
+
+ /* the start of physical memory */
+ uint64_t dh_memory_start;
+
+ /* the end of physical memory */
+ uint64_t dh_memory_end;
+
+#if DUMP_DEBUG >= 6
+ /* the number of bytes in this dump specifically */
+ uint64_t dh_num_bytes;
+#endif
+
+ /* the number of hardware/physical pages in this dump specifically */
+ uint32_t dh_num_dump_pages;
+
+ /* the panic string, if available */
+ char dh_panic_string[DUMP_PANIC_LEN];
+
+ /* timeval depends on architecture, two long values */
+ struct {uint64_t tv_sec;
+ uint64_t tv_usec;
+ } dh_time; /* the time of the system crash */
+
+ /* the NEW utsname (uname) information -- in character form */
+ /* we do this so we don't have to include utsname.h */
+ /* plus it helps us be more architecture independent */
+ /* now maybe one day soon they'll make the [65] a #define! */
+ char dh_utsname_sysname[65];
+ char dh_utsname_nodename[65];
+ char dh_utsname_release[65];
+ char dh_utsname_version[65];
+ char dh_utsname_machine[65];
+ char dh_utsname_domainname[65];
+
+ /* the address of current task (OLD = void *, NEW = uint64_t) */
+ uint64_t dh_current_task;
+
+ /* what type of compression we're using in this dump (if any) */
+ uint32_t dh_dump_compress;
+
+ /* any additional flags */
+ uint32_t dh_dump_flags;
+
+ /* any additional flags */
+ uint32_t dh_dump_device;
+
+} __attribute__((packed)) dump_header_t;
+
+/*
+ * Structure: dump_page_t
+ * Function: To act as the header associated to each physical page of
+ * memory saved in the system crash dump. This allows for
+ * easy reassembly of each crash dump page. The address bits
+ * are split to make things easier for 64-bit/32-bit system
+ * conversions.
+ *
+ * dp_byte_offset and dp_page_index are landmarks that are helpful when
+ * looking at a hex dump of /dev/vmdump,
+ */
+typedef struct _dump_page_s {
+
+#if DUMP_DEBUG >= 6
+ /* byte offset */
+ uint64_t dp_byte_offset;
+
+ /* page index */
+ uint64_t dp_page_index;
+#endif
+ /* the address of this dump page */
+ uint64_t dp_address;
+
+ /* the size of this dump page */
+ uint32_t dp_size;
+
+ /* flags (currently DUMP_COMPRESSED, DUMP_RAW or DUMP_END) */
+ uint32_t dp_flags;
+} __attribute__((packed)) dump_page_t;
+
+/*
+ * This structure contains information needed for the lkcdutils
+ * package (particularly lcrash) to determine what information is
+ * associated to this kernel, specifically.
+ */
+typedef struct lkcdinfo_s {
+ int arch;
+ int ptrsz;
+ int byte_order;
+ int linux_release;
+ int page_shift;
+ int page_size;
+ uint64_t page_mask;
+ uint64_t page_offset;
+ int stack_offset;
+} lkcdinfo_t;
+
+#ifdef __KERNEL__
+
+/*
+ * Structure: dump_compress_t
+ * Function: This is what an individual compression mechanism can use
+ * to plug in their own compression techniques. It's always
+ * best to build these as individual modules so that people
+ * can put in whatever they want.
+ */
+typedef struct dump_compress_s {
+ /* the list_head structure for list storage */
+ struct list_head list;
+
+ /* the type of compression to use (DUMP_COMPRESS_XXX) */
+ int compress_type;
+
+ /* the compression function to call */
+ int (*compress_func)(char *, int, char *, int);
+} dump_compress_t;
+
+/* functions for dump compression registration */
+extern void dump_register_compression(dump_compress_t *);
+extern void dump_unregister_compression(int);
+
+/*
+ * Structure dump_mbank[]:
+ *
+ * For CONFIG_DISCONTIGMEM systems this array specifies the
+ * memory banks/chunks that need to be dumped after a panic.
+ *
+ * For classic systems it specifies a single set of pages from
+ * 0 to max_mapnr.
+ */
+typedef struct dump_mbank {
+ u64 start;
+ u64 end;
+ int type;
+ int pad1;
+ long pad2;
+} dump_mbank_t;
+
+#define DUMP_MBANK_TYPE_CONVENTIONAL_MEMORY 1
+#define DUMP_MBANK_TYPE_OTHER 2
+
+
+#define MAXCHUNKS 256
+extern int dump_mbanks;
+extern dump_mbank_t dump_mbank[MAXCHUNKS];
+
+extern struct notifier_block *dump_notifier_list;
+extern int register_dump_notifier(struct notifier_block *);
+extern int unregister_dump_notifier(struct notifier_block *);
+
+/* notification event codes */
+#define DUMP_BEGIN_NONDISRUPT 0x0000 /* Notify of non-disruptive dump beginning */
+#define DUMP_BEGIN 0x0001 /* Notify of distuptive dump beginning */
+#define DUMP_END 0x0002 /* Notify of dump ending */
+#define DUMP_TEST 0x0003 /* Notify Just probeing for capability callbacks */
+
+extern int dump_init(void);
+int dump_execute(char *, struct pt_regs *);
+extern volatile int dump_in_progress;
+extern volatile int dumping_cpu;
+extern int (*dump_function_ptr)(char *, struct pt_regs *);
+extern volatile int dump_started;
+
+/*
+ * dump notifier callbacks to tune the dump driver for
+ * the disk driver that will be used for the dump. They
+ * are used to modify the dump driver from it's default
+ * behavior.
+ *
+ * NOTE: To support changing the dump device between a
+ * non-disruptive dump and a future dump we would
+ * need to provide the inverse functions also.
+ */
+extern void dump_scheduler_enable(void);
+extern void dump_interrupts_disable(void);
+extern void dump_nondisruptive_disable(void);
+
+static inline void dump(char * str, struct pt_regs * regs)
+{
+ if (dump_function_ptr) {
+ dump_function_ptr((char *)str, regs);
+ }
+}
+
+/*
+ * Common Arch Specific Functions should be declared here.
+ * This allows the C compiler to detect discrepancies.
+ */
+extern void __dump_open(void);
+extern void __dump_cleanup(void);
+extern void __dump_init(uint64_t);
+extern int __dump_configure_header(struct pt_regs *);
+extern unsigned int __dump_silence_system(unsigned int);
+extern unsigned int __dump_resume_system(unsigned int);
+
+#define DUMP_MODULE_NAME "dump"
+#if DUMP_DEBUG
+#define DUMP_PREFIX __func__
+#else
+#define DUMP_PREFIX DUMP_MODULE_NAME
+#endif
+
+#define DUMP_PRINTN(args...) { \
+ printk("\n"); \
+ DUMP_PRINTF(args); \
+}
+
+#define DUMP_PRINTF(args...) { \
+ printk("%s: ", DUMP_PREFIX); \
+ printk (args); \
+}
+
+#ifdef DUMP_DEBUG
+#define DUMP_DPRINTF(args...) { \
+ printk("%s: ", DUMP_PREFIX); \
+ printk (args); \
+}
+#else
+#define DUMP_DPRINTF(args...)
+#endif
+
+#define DUMP_PRINT(args...) { \
+ printk(args); \
+}
+
+#ifndef KERNEL_VERSION
+#define KERNEL_VERSION(a,b,c) (((a) << 16) | ((b) << 8) | (c))
+#endif
+
+#endif /* __KERNEL__ */
+#endif /* _DUMP_H */
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH] 2.5.44: lkcd (9/9): dump driver and build files
2002-10-21 10:16 [PATCH] 2.5.44: lkcd (9/9): dump driver and build files Matt D. Robinson
@ 2002-10-21 21:21 ` Christoph Hellwig
2002-10-21 19:07 ` Matt D. Robinson
` (3 more replies)
0 siblings, 4 replies; 16+ messages in thread
From: Christoph Hellwig @ 2002-10-21 21:21 UTC (permalink / raw)
To: Matt D. Robinson; +Cc: linux-kernel
On Mon, Oct 21, 2002 at 03:16:05AM -0700, Matt D. Robinson wrote:
> diff -Naur linux-2.5.44.orig/drivers/dump/Makefile linux-2.5.44.lkcd/drivers/dump/Makefile
> --- linux-2.5.44.orig/drivers/dump/Makefile Wed Dec 31 16:00:00 1969
> +++ linux-2.5.44.lkcd/drivers/dump/Makefile Sat Oct 19 12:39:15 2002
> @@ -0,0 +1,30 @@
> +#
> +# Makefile for the dump device drivers.
> +#
> +# 12 June 2000, Christoph Hellwig <schch@pe.tu-clausthal.de>
> +# Rewritten by Matt D. Robinson (yakker@sourceforge.net) for
> +# the dump directory.
*cough* is that an old mail address and I can't even remember having
touched that file.. :) What about remoing that note..
> +#include <linux/devfs_fs_kernel.h>
Can't see any devfs code used in this file..
> +#include <linux/delay.h>
> +#include <linux/reboot.h>
> +#include <linux/fs.h>
> +#include <linux/mm.h>
> +#include <linux/swap.h>
> +#include <linux/dump.h>
> +#include <linux/smp_lock.h>
Can't see lock_kernel/unlock_kernel used in this file,
please check whether you have more unneeded includes.
> +/*
> + * Handle printing of 64-bit values
> + *
> + * NOTE: on ia64 %llx is recommended for ia32.
> + * on RedHat 7.2 %llx work in user space but not in the kernel.
> + * Perhaps this is dependent on the kernel version.
> + */
> +#if BITS_PER_LONG == 64
> +#define PU64X "%lx"
> +#else
> +#define PU64X "%Lx"
> +#endif
Argg. Just always cast to long long and use %llx.
> +/* Dump tunables */
> +kdev_t dump_device; /* the actual kdev_t device number */
Should be dev_T.
> +int dump_level; /* the current dump level */
> +int dump_compress; /* whether to try to compress each page */
> +int dump_flags; /* whether to try to compress each page */
> +
> +/* Dump Notifier Tunables */
> +long dump_scheduler_enabled = 0; /* Default: scheduler is disabled */
> +long dump_interrupts_enabled = 1; /* Default: interrupts stay enabled */
> +long dump_nondisruptive_enabled = 1; /* Default: non-disruptive enabled */
> +
> +/* Other global fields */
> +void *dump_page_buf; /* dump page buffer for memcpy()! */
> +void *dump_page_buf_0; /* dump page buffer returned by kmalloc */
> +dump_header_t dump_header; /* the primary dump header */
> +dump_header_asm_t dump_header_asm; /* the arch-specific dump header */
> +loff_t dump_fpos; /* the offset in the output device */
> +int dump_mbanks; /* number of physical memory banks */
> +dump_mbank_t dump_mbank[MAXCHUNKS];/* describes layout of physical memory */
> +long dump_unreserved_mem = 0; /* Save Pages even if it isn't reserved */
> +long dump_unreferenced_mem = 0; /* Save Pages even if page_count == 0 */
> +long dump_nonconventional_mem = 0; /* Save non-conventional mem (firmware) */
> +volatile int dump_started = 0; /* Indicated we are about to dump */
Using volatile is almost always a bug. USe atomic variables
or bitops instead.
> +static struct dump_operations *dump_device_ops = 0;
> +
> +static int dump_compress_none(char *old, int oldsize, char *new, int newsize);
How many of those could be static?
> +
> +static dump_compress_t dump_none_compression = {
> + compress_type: DUMP_COMPRESS_NONE,
> + compress_func: dump_compress_none,
> +};
C99 initializers.
> +#if DUMP_DEBUG
> +void dump_bp(void) {}
> +#endif
Doesn't seem to be implemented at all..
> + * Name: dump_read_proc()
> + * Func: Read the proc data for dump tunables.
> + */
> +static int
> +dump_read_proc(char *page, char **start, off_t off,
> + int count, int *eof, void *data)
> +{
> + int len;
> + char *out = page;
> + struct proc_dir_entry *p = (struct proc_dir_entry *)data;
> +
> +
> + if (0 == strcmp(p->name, DUMP_LEVEL_NAME)) {
> + out += sprintf(out, "%d\n", dump_level);
> + len = out - page;
> + } else if (0 == strcmp(p->name, DUMP_FLAGS_NAME)) {
> + out += sprintf(out, "%d\n", dump_flags);
> + len = out - page;
> + } else if (0 == strcmp(p->name, DUMP_COMPRESS_NAME)) {
> + out += sprintf(out, "%d\n", dump_compress);
> + len = out - page;
> + } else if (0 == strcmp(p->name, DUMP_DEVICE_NAME)) {
> + out += sprintf(out, "0x%x\n", kdev_val(dump_device));
> + len = out - page;
> + } else {
> + return (0);
> + }
> + len -= off;
> + if (len < count) {
> + *eof = 1;
> + if (len <= 0) return 0;
> + } else {
> + len = count;
> + }
> + *start = page + off;
> + return (len);
> +}
This wants to be changed to either seq_file or sysctl. Sysctl
might be better for the one value per file approach.
> +static int
> +dump_compress_none(char *old, int oldsize, char *new, int newsize)
> +{
> + /* just return the old size */
> + return (oldsize);
return style again.
> +void dump_scheduler_enable(void)
> +{
> + DUMP_DPRINTF("setting dump_scheduler_enabled = 1\n");
> + dump_scheduler_enabled = 1;
> +}
Can't see this called anywhere
> +
> +void dump_interrupts_disable(void)
> +{
> + DUMP_DPRINTF("setting dump_interrupts_enabled = 0\n");
> + dump_interrupts_enabled = 0;
> +}
Dito.
> +
> +void dump_nondisruptive_disable(void)
> +{
> + DUMP_DPRINTF("setting dump_nondisruptive_enabled = 0\n");
> + dump_nondisruptive_enabled = 0;
> +}
Dito.
> +static int
> +dump_add_page(unsigned long page_index, unsigned long *toffset, int pass)
> +{
> +#if defined(CONFIG_X86) || defined(CONFIG_ALPHA)
> + extern int page_is_ram(unsigned long);
> +#endif
Yuck. Please just declare page_is_ram for every port.
> +#if !defined(CONFIG_DISCONTIGMEM) && !defined(CONFIG_IA64)
> + p = (struct page *) &(mem_map[page_index]);
Yuck. Please don't use mem_map in common code.
> +#ifdef CONFIG_HIGHMEM
> + if (PageHighMem(p)) {
> + /*
> + * Since this can be executed from IRQ context,
> + * reentrance on the same CPU must be avoided:
> + */
> + vaddr = kmap_atomic(p, KM_USER0);
> + }
> + else
kmap_atomic is a noop for !CONFIG_HIGHMEM - make this code unconditional.
> +#if !defined(CONFIG_DISCONTIGMEM) && !defined(CONFIG_IA64)
> + if (!kern_addr_valid(dp.dp_address)) {
> + /* dump of I/O memory not supported yet */
> + printk(KERN_ALERT "dump_add_page: !kern_addr_valid"
> + "(dp.dp_address: " PU64X "\n", dp.dp_address);
> + return(1);
> + }
> +#endif
Why don't you do this uncoditional?
> +static int
> +dump_ioctl(struct inode *i, struct file *f, unsigned int cmd, unsigned long arg)
> +{
> + /* check capabilities */
> + if (!capable(CAP_SYS_ADMIN))
> + return (-EPERM);
> +
> + /*
> + * This is the main mechanism for controlling get/set data
> + * for various dump device parameters. The real trick here
> + * is setting the dump device (DIOSDUMPDEV). That's what
> + * triggers everything else.
> + */
> + switch (cmd) {
> + /* set dump_device */
> + case DIOSDUMPDEV:
> + /* check flags */
> + if (!(f->f_flags & O_RDWR))
> + return (-EPERM);
> +
> + __dump_open();
> + return (dump_open_kdev(to_kdev_t((dev_t)arg)));
> +
> + /* get dump_device */
> + case DIOGDUMPDEV:
> + return (put_user((long)kdev_val(dump_device), (long *)arg));
> +
> + /* set dump_level */
> + case DIOSDUMPLEVEL:
> + /* check flags */
> + if (!(f->f_flags & O_RDWR))
> + return (-EPERM);
> +
> + /* make sure we have a positive value */
> + if (arg < 0)
> + return (-EINVAL);
> + dump_level = (int)arg;
> +
> + /*
> + * REMIND: Still in development:
> + * We will consider reserved pages a initial proxy
> + * for kernel pages.
> + */
> + if (dump_level > DUMP_LEVEL_KERN)
> + dump_unreserved_mem = 1;
> + else
> + dump_unreserved_mem = 0;
> +
> + /*
> + * REMIND: Still in development:
> + * Using refcount > 1 as a proxy for kernel & user
> + * pages.
> + */
> + if (dump_level > DUMP_LEVEL_USED)
> + dump_unreferenced_mem = 1;
> + else
> + dump_unreferenced_mem = 0;
> +
> + /*
> + * REMIND: Still in development:
> + * This may not be 100% stable on all ia64
> + * memory banks. Accessing uncached memory
> + * with cached accesses can cause subsequent
> + * bus errors when the cache is flushed.
> + */
> + if (dump_level > DUMP_LEVEL_ALL_RAM)
> + dump_nonconventional_mem = 1;
> + else
> + dump_nonconventional_mem = 0;
> + break;
> +
> + /* get dump_level */
> + case DIOGDUMPLEVEL:
> + return (put_user((long)dump_level, (long *)arg));
> +
> + /* set dump_flags */
> + case DIOSDUMPFLAGS:
> + /* check flags */
> + if (!(f->f_flags & O_RDWR))
> + return (-EPERM);
> +
> + /* make sure we have a positive value */
> + if (arg < 0)
> + return (-EINVAL);
> +
> + dump_flags = (int)arg;
> + break;
> +
> + /* get dump_flags */
> + case DIOGDUMPFLAGS:
> + return (put_user((long)dump_flags, (long *)arg));
> +
> + /* set the dump_compress status */
> + case DIOSDUMPCOMPRESS:
> + /* check flags */
> + if (!(f->f_flags & O_RDWR))
> + return (-EPERM);
> +
> + return (dump_compress_init((int)arg));
> +
> + /* get the dump_compress status */
> + case DIOGDUMPCOMPRESS:
> + return (put_user((long)dump_compress, (long *)arg));
> +
> + }
> + return (0);
I don't think ioctl is the right interface. Most of those want to be sysctls.
> +/*
> + * Name: dump_open()
> + * Func: Open the dump device for use when the system crashes.
> + */
> +static int
> +dump_open(struct inode *i, struct file *f)
> +{
> + /* opening a device is straightforward -- nothing to do here */
> + return (0);
> +}
Remove it.
> +/*
> + * Name: dump_init()
> + * Func: Initialize the dump process. This will set up any architecture
> + * dependent code. The big key is we need the memory offsets before
> + * the page table is initialized, because the base memory offset
> + * is changed after paging_init() is called.
> + */
> +int __init
> +dump_init(void)
static
> +{
> + struct sysinfo info;
> + int i;
> +
> + /* try to initialize /proc interfaces */
> + if (dump_proc_init() < 0) {
> + DUMP_PRINTF("dump_proc_init failed!; dump not initialized\n");
> + return (-EBUSY);
> + }
> +
> + /* try to create our dump device */
> + if (register_chrdev(DUMP_MAJOR, "dump", &dump_fops)) {
> + DUMP_PRINTF("cannot register dump character device!\n");
> + return (-EBUSY);
> + }
> +
> + /* initialize the dump headers to zero */
> + memset(&dump_header, 0, sizeof(dump_header));
> + memset(&dump_header_asm, 0, sizeof(dump_header_asm));
> +
> +#if !defined(CONFIG_DISCONTIGMEM) && !defined(CONFIG_IA64)
> + /*
> + * CONFIG_DISCONTIGMEM and CONFIG_IA64 systems are responsible
> + * for initializing dump_mbank[] in __dump_init().
> + */
> + dump_mbanks = 1;
> + dump_mbank[0].start = 0;
> + dump_mbank[0].end = (((u64) max_mapnr) << PAGE_SHIFT) - 1;
> + dump_mbank[0].type = DUMP_MBANK_TYPE_CONVENTIONAL_MEMORY;
> +#endif
Just move it to arch code for everyone.
> +void __exit
> +dump_cleanup(void)
static
> + /* try to create our dump device */
> + if (unregister_chrdev(DUMP_MAJOR, "dump"))
> + DUMP_PRINT("cannot unregister dump character device!\n");
the printk is rather pointless..
> +#ifdef MODULE
> +#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,4,16))
> +#if !defined(MODULE_LICENSE)
> +#define MODULE_LICENSE(str)
> +#endif
> +#endif
kill this ifdef junk.
> +
> +#define DUMP_MODULE_NAME "dump_blockdev"
doesn't seem to be used.
> +
> +/*
> + * -----------------------------------------------------------------------
> + * V A R I A B L E S
> + * -----------------------------------------------------------------------
> + */
> +kdev_t dump_dev; /* the actual kdev_t device number */
didn't we already have this one in dump_base.c?
> +void *dump_page_buffer; /* dump page buffer for memcpy()! */
> +int dump_blk_size; /* sector size for dump_device */
> +int dump_blk_shift; /* shift need to convert to sector size */
> +struct bio *dump_bio; /* bio structure for io request */
> +loff_t dump_offset; /* the offset in the output device */
> +struct block_device *dump_bdev = NULL;
> +unsigned long dumpdev_limit; /* the size limit of the block device */
> +volatile int bio_complete = 1;/* Indicates the completion of each bio request */
> +int dump_io_abort = 0; /* set by end_io routine during io error */
Shouldn't much of this be static? again volatile is seldomly a good idea.
> +static void
> +dump_free_bio(void)
> +{
> + if (dump_bio && dump_bio->bi_io_vec)
> + kfree(dump_bio->bi_io_vec);
> + if (dump_bio)
> + kfree(dump_bio);
> +}
kfree(NULL) is fine.
> +/*
> + * Name: dump_open_kdev()
> + * Func: Try to open the kdev_t argument as the real dump device.
> + * This is where all the work is done for setting up the dump
> + * device. It's assumed at this point that by passing in the
> + * dump device's major/minor number, we can open it up, check
> + * it out, and use it for whatever purposes.
> + */
> +static int
> +dump_open_kdev(kdev_t tmp_dump_device)
Should take a dev_t.
> + /* release earlier dump_bdev if present */
> + if (dump_bdev) {
> + blkdev_put(dump_bdev, BDEV_RAW);
> + dump_bdev = NULL;
> + }
Shouldn't this have gone away in ->close?
> +
> + dump_bdev = bdget(kdev_t_to_nr(tmp_dump_device));
> + if (!dump_bdev) {
> + retval = -ENODEV;
> + goto err;
> + }
> +
> + if (blkdev_get(dump_bdev, O_RDWR | O_LARGEFILE, 0, BDEV_RAW)) {
> + retval = -ENODEV;
> + goto err1;
> + }
bd_claim is missing
> +
> + if ((dump_page_buffer== (void *)NULL)) {
(void *)NULL) is silly
> + retval = -EINVAL;
> + goto err2;
> + }
> +
> + if (dump_bio)
> + dump_free_bio();
> +
> + if ((dump_bio = kmalloc(sizeof(struct bio), GFP_KERNEL)) == NULL) {
> + DUMP_PRINTF("Cannot allocate bio\n");
> + retval = -ENOMEM;
> + goto err2;
> + }
Shouldn't you use the generic bio allocator?
> +static int
> +dev_dump_ioctl(unsigned int cmd, unsigned long arg)
> +{
> + int ret = 0;
> +
> + /*
> + * This is the main mechanism for controlling get/set data
> + * for various dump device parameters. The real trick here
> + * is setting the dump device (DIOSDUMPDEV). That's what
> + * triggers everything else.
> + */
> + switch (cmd) {
> + case DIOSDUMPDEV:
> + ret = dump_open_kdev(to_kdev_t((dev_t)arg));
> + break;
> + case DIOSDUMPMEM:
> + dump_page_buffer = (void *)arg;
> + break;
> + default:
> + break;
> +
> + }
> + return (ret);
> +}
ioctl is not a replacement for sane interfaces again!
> +static struct dump_operations dump_blockdev_ops = {
> + dump_open: dev_dump_open,
> + dump_release: dev_dump_release,
> + dump_ioctl: dev_dump_ioctl,
> + dump_write: dev_dump_write,
> + dump_seek: dev_dump_seek,
> + dump_start: dev_dump_start,
> + dump_end: dev_dump_end,
> + dump_ready: dev_dump_ready,
> +};
Indentation seems strange, wants C99 initializers.
> +int __init
> +dump_blockdev_init(void)
static
> +{
> + dump_page_buffer = NULL;
> + dump_offset = 0;
.bbs is per-zeroed.
> +void __exit
> +dump_blockdev_cleanup(void)
static.
> +#ifdef MODULE
> +#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,4,16))
> +#if !defined(MODULE_LICENSE)
> +#define MODULE_LICENSE(str)
> +#endif
> +#endif
> +
> +MODULE_AUTHOR("Mohamed. Abbas");
> +MODULE_DESCRIPTION("Block Device Driver for Linux Kernel Crash Dump (LKCD)");
> +#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,16))
> +MODULE_LICENSE("GPL");
> +#endif
> +#endif /* MODULE */
more ifdef-crap to kill.
> + int i;
> + void *ptr;
> +
> + if (dump_header_asm.dha_stack[0])
> + return 0;
> +
> + ptr = vmalloc(THREAD_SIZE * num_online_cpus());
> + if (!ptr) {
very strange indention..
> +typedef struct _dump_header_asm_s {
Please DON'T do typedefs. just struct _dump_header_asm!
> + /* the dump magic number -- unique to verify dump is valid */
> + uint64_t dha_magic_number;
u64 & co
> +#ifdef __KERNEL__
kernel/user headers usually aren't shared..
> +/* define TRUE and FALSE for use in our dump modules */
> +#ifndef FALSE
> +#define FALSE 0
> +#endif
> +
> +#ifndef TRUE
> +#define TRUE 1
> +#endif
Please just use 0/1 like evreryone else.
> +#if DUMP_DEBUG
> +void dump_bp(void); /* Called when something exceptional occurs */
> +#define DUMP_BP() dump_bp() /* Breakpoint */
> +#else
> +#define DUMP_BP()
> +#endif
It doesn't look like this actually works.
> +/* necessary header definitions in all cases */
> +#define DUMP_KIOBUF_NUMBER 0xdeadbeef /* special number for kiobuf maps */
kiobufs are gone in 2.5.44.
> +typedef struct dump_mbank {
> + u64 start;
> + u64 end;
> + int type;
> + int pad1;
> + long pad2;
> +} dump_mbank_t;
identation is once again rather strange.
> +#ifndef KERNEL_VERSION
> +#define KERNEL_VERSION(a,b,c) (((a) << 16) | ((b) << 8) | (c))
> +#endif
kill this.
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH] 2.5.44: lkcd (9/9): dump driver and build files
2002-10-21 21:21 ` Christoph Hellwig
@ 2002-10-21 19:07 ` Matt D. Robinson
2002-10-21 22:06 ` Piet Delaney
` (2 subsequent siblings)
3 siblings, 0 replies; 16+ messages in thread
From: Matt D. Robinson @ 2002-10-21 19:07 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: linux-kernel
There's a lot of stuff to change in your suggestions, my team
will be working on it over the next night or two. We should
be able to integrate most modifications. It's normally testing
that consumes most of the time.
Thanks, Christoph.
--Matt
On Mon, 21 Oct 2002, Christoph Hellwig wrote:
|>On Mon, Oct 21, 2002 at 03:16:05AM -0700, Matt D. Robinson wrote:
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH] 2.5.44: lkcd (9/9): dump driver and build files
2002-10-21 21:21 ` Christoph Hellwig
2002-10-21 19:07 ` Matt D. Robinson
@ 2002-10-21 22:06 ` Piet Delaney
2002-10-22 18:47 ` Christoph Hellwig
2002-10-22 2:04 ` Nicholas Wourms
2002-10-22 15:05 ` Suparna Bhattacharya
3 siblings, 1 reply; 16+ messages in thread
From: Piet Delaney @ 2002-10-21 22:06 UTC (permalink / raw)
To: Christoph Hellwig
Cc: Matt D. Robinson, linux-kernel, piet, Keith Owens, steiner,
jeremy
On Mon, 2002-10-21 at 14:21, Christoph Hellwig wrote:
> On Mon, Oct 21, 2002 at 03:16:05AM -0700, Matt D. Robinson wrote:
> > diff -Naur linux-2.5.44.orig/drivers/dump/Makefile linux-2.5.44.lkcd/drivers/dump/Makefile
> > --- linux-2.5.44.orig/drivers/dump/Makefile Wed Dec 31 16:00:00 1969
> > +++ linux-2.5.44.lkcd/drivers/dump/Makefile Sat Oct 19 12:39:15 2002
> > @@ -0,0 +1,30 @@
> > +#
> > +# Makefile for the dump device drivers.
> > +#
> > +# 12 June 2000, Christoph Hellwig <schch@pe.tu-clausthal.de>
> > +# Rewritten by Matt D. Robinson (yakker@sourceforge.net) for
> > +# the dump directory.
>
> *cough* is that an old mail address and I can't even remember having
> touched that file.. :) What about remoing that note..
>
> > +#include <linux/devfs_fs_kernel.h>
>
> Can't see any devfs code used in this file..
>
> > +#include <linux/delay.h>
> > +#include <linux/reboot.h>
> > +#include <linux/fs.h>
> > +#include <linux/mm.h>
> > +#include <linux/swap.h>
> > +#include <linux/dump.h>
> > +#include <linux/smp_lock.h>
>
> Can't see lock_kernel/unlock_kernel used in this file,
> please check whether you have more unneeded includes.
>
> > +/*
> > + * Handle printing of 64-bit values
> > + *
> > + * NOTE: on ia64 %llx is recommended for ia32.
> > + * on RedHat 7.2 %llx work in user space but not in the kernel.
> > + * Perhaps this is dependent on the kernel version.
> > + */
> > +#if BITS_PER_LONG == 64
> > +#define PU64X "%lx"
> > +#else
> > +#define PU64X "%Lx"
> > +#endif
>
> Argg. Just always cast to long long and use %llx.
At Sun they consider that to be of poor taste. I used this
approach after having been "educated" by the Solaris kernel
folks about this. It's likely a religious issue. I like
the simplicity of casting to long long and useing %llx.
>
> > +/* Dump tunables */
> > +kdev_t dump_device; /* the actual kdev_t device number */
>
> Should be dev_T.
>
> > +int dump_level; /* the current dump level */
> > +int dump_compress; /* whether to try to compress each page */
> > +int dump_flags; /* whether to try to compress each page */
> > +
> > +/* Dump Notifier Tunables */
> > +long dump_scheduler_enabled = 0; /* Default: scheduler is disabled */
> > +long dump_interrupts_enabled = 1; /* Default: interrupts stay enabled */
> > +long dump_nondisruptive_enabled = 1; /* Default: non-disruptive enabled */
> > +
> > +/* Other global fields */
> > +void *dump_page_buf; /* dump page buffer for memcpy()! */
> > +void *dump_page_buf_0; /* dump page buffer returned by kmalloc */
> > +dump_header_t dump_header; /* the primary dump header */
> > +dump_header_asm_t dump_header_asm; /* the arch-specific dump header */
> > +loff_t dump_fpos; /* the offset in the output device */
> > +int dump_mbanks; /* number of physical memory banks */
> > +dump_mbank_t dump_mbank[MAXCHUNKS];/* describes layout of physical memory */
> > +long dump_unreserved_mem = 0; /* Save Pages even if it isn't reserved */
> > +long dump_unreferenced_mem = 0; /* Save Pages even if page_count == 0 */
> > +long dump_nonconventional_mem = 0; /* Save non-conventional mem (firmware) */
> > +volatile int dump_started = 0; /* Indicated we are about to dump */
>
> Using volatile is almost always a bug. USe atomic variables
> or bitops instead.
Yea, volatile is just being used to implement a simple atomic variable.
> > +static struct dump_operations *dump_device_ops = 0;
> > +
> > +static int dump_compress_none(char *old, int oldsize, char *new, int newsize);
>
> How many of those could be static?
>
> > +
> > +static dump_compress_t dump_none_compression = {
> > + compress_type: DUMP_COMPRESS_NONE,
> > + compress_func: dump_compress_none,
> > +};
>
> C99 initializers.
What's C99?
>
> > +#if DUMP_DEBUG
> > +void dump_bp(void) {}
> > +#endif
>
> Doesn't seem to be implemented at all.
.
dump_bp() is just a debugging hook that's
enabled while debugging the lkcd dump driver.
DUMP_DEBUG can be defined in dump.h and allows
the kernel and user space code to be instrumented
for easier debugging. I found it useful while debugging.
>
> > + * Name: dump_read_proc()
> > + * Func: Read the proc data for dump tunables.
> > + */
> > +static int
> > +dump_read_proc(char *page, char **start, off_t off,
> > + int count, int *eof, void *data)
> > +{
> > + int len;
> > + char *out = page;
> > + struct proc_dir_entry *p = (struct proc_dir_entry *)data;
> > +
> > +
> > + if (0 == strcmp(p->name, DUMP_LEVEL_NAME)) {
> > + out += sprintf(out, "%d\n", dump_level);
> > + len = out - page;
> > + } else if (0 == strcmp(p->name, DUMP_FLAGS_NAME)) {
> > + out += sprintf(out, "%d\n", dump_flags);
> > + len = out - page;
> > + } else if (0 == strcmp(p->name, DUMP_COMPRESS_NAME)) {
> > + out += sprintf(out, "%d\n", dump_compress);
> > + len = out - page;
> > + } else if (0 == strcmp(p->name, DUMP_DEVICE_NAME)) {
> > + out += sprintf(out, "0x%x\n", kdev_val(dump_device));
> > + len = out - page;
> > + } else {
> > + return (0);
> > + }
> > + len -= off;
> > + if (len < count) {
> > + *eof = 1;
> > + if (len <= 0) return 0;
> > + } else {
> > + len = count;
> > + }
> > + *start = page + off;
> > + return (len);
> > +}
>
> This wants to be changed to either seq_file or sysctl. Sysctl
> might be better for the one value per file approach.
Perhaps the usefulness of the various aproaches during early startup
should be considered. In RedHat 8.0 there does seem to be existant
hooks for user space core dumps in /etc/sysctl.conf:
----------------------------------------------------------------------
Controls whether core dumps will append the PID to the core filename.
# Useful for debugging multi-threaded applications.
kernel.core_uses_pid =
----------------------------------------------------------------------
When is /etc/sysctl.conf read by the kernel?
Supporting core file generation as soon as possible during startup
should be given high priority.
>
> > +static int
> > +dump_compress_none(char *old, int oldsize, char *new, int newsize)
> > +{
> > + /* just return the old size */
> > + return (oldsize);
>
> return style again.
>
> > +void dump_scheduler_enable(void)
> > +{
> > + DUMP_DPRINTF("setting dump_scheduler_enabled = 1\n");
> > + dump_scheduler_enabled = 1;
> > +}
>
> Can't see this called anywhere
It's a callback used by the dump driver. These callbacks are
used by disk drivers, like the SGI SCSI driver, to tune the
dump driver for it's needs. The callback facility was added
to the dump driver and this tuning for the device driver seemed
like a natural user of the facility.
>
> > +
> > +void dump_interrupts_disable(void)
> > +{
> > + DUMP_DPRINTF("setting dump_interrupts_enabled = 0\n");
> > + dump_interrupts_enabled = 0;
> > +}
>
> Dito.
For example, the SGI SCSI driver may need to have interrupts
disabled once the SCSI driver switches to dump mode. When
I added this the SGI SCSI driver had to run with interrupts
disabled once the disk driver was setup for dumping. Actually
dumping with interrupts enabled will likely eventually not
be supported.
>
> > +
> > +void dump_nondisruptive_disable(void)
> > +{
> > + DUMP_DPRINTF("setting dump_nondisruptive_enabled = 0\n");
> > + dump_nondisruptive_enabled = 0;
> > +}
>
> Dito.
This is here to allow the dump driver to avoid trying to do
a nondistruptive dump when in fact the disk driver can support it.
If not here the nondisruptive dump will hang. This just makes
the dump driver bullet proof.
>
> > +static int
> > +dump_add_page(unsigned long page_index, unsigned long *toffset, int pass)
> > +{
> > +#if defined(CONFIG_X86) || defined(CONFIG_ALPHA)
> > + extern int page_is_ram(unsigned long);
> > +#endif
>
> Yuck. Please just declare page_is_ram for every port.
>
> > +#if !defined(CONFIG_DISCONTIGMEM) && !defined(CONFIG_IA64)
> > + p = (struct page *) &(mem_map[page_index]);
>
> Yuck. Please don't use mem_map in common code.
Yea the NUMA Ia64 code can't use it; I dind't see
and easy way of replacing it. What do you suggest?
>
> > +#ifdef CONFIG_HIGHMEM
> > + if (PageHighMem(p)) {
> > + /*
> > + * Since this can be executed from IRQ context,
> > + * reentrance on the same CPU must be avoided:
> > + */
> > + vaddr = kmap_atomic(p, KM_USER0);
> > + }
> > + else
>
> kmap_atomic is a noop for !CONFIG_HIGHMEM - make this code unconditional.
>
> > +#if !defined(CONFIG_DISCONTIGMEM) && !defined(CONFIG_IA64)
> > + if (!kern_addr_valid(dp.dp_address)) {
> > + /* dump of I/O memory not supported yet */
> > + printk(KERN_ALERT "dump_add_page: !kern_addr_valid"
> > + "(dp.dp_address: " PU64X "\n", dp.dp_address);
> > + return(1);
> > + }
> > +#endif
>
> Why don't you do this
Perhaps it could. Perhaps kern_addr_valid() doesn't work for ia64.
I'd have to check to be sure.
>
> > +static int
> > +dump_ioctl(struct inode *i, struct file *f, unsigned int cmd, unsigned long arg)
> > +{
> > + /* check capabilities */
> > + if (!capable(CAP_SYS_ADMIN))
> > + return (-EPERM);
> > +
> > + /*
> > + * This is the main mechanism for controlling get/set data
> > + * for various dump device parameters. The real trick here
> > + * is setting the dump device (DIOSDUMPDEV). That's what
> > + * triggers everything else.
> > + */
> > + switch (cmd) {
> > + /* set dump_device */
> > + case DIOSDUMPDEV:
> > + /* check flags */
> > + if (!(f->f_flags & O_RDWR))
> > + return (-EPERM);
> > +
> > + __dump_open();
> > + return (dump_open_kdev(to_kdev_t((dev_t)arg)));
> > +
> > + /* get dump_device */
> > + case DIOGDUMPDEV:
> > + return (put_user((long)kdev_val(dump_device), (long *)arg));
> > +
> > + /* set dump_level */
> > + case DIOSDUMPLEVEL:
> > + /* check flags */
> > + if (!(f->f_flags & O_RDWR))
> > + return (-EPERM);
> > +
> > + /* make sure we have a positive value */
> > + if (arg < 0)
> > + return (-EINVAL);
> > + dump_level = (int)arg;
> > +
> > + /*
> > + * REMIND: Still in development:
> > + * We will consider reserved pages a initial proxy
> > + * for kernel pages.
> > + */
> > + if (dump_level > DUMP_LEVEL_KERN)
> > + dump_unreserved_mem = 1;
> > + else
> > + dump_unreserved_mem = 0;
> > +
> > + /*
> > + * REMIND: Still in development:
> > + * Using refcount > 1 as a proxy for kernel & user
> > + * pages.
> > + */
> > + if (dump_level > DUMP_LEVEL_USED)
> > + dump_unreferenced_mem = 1;
> > + else
> > + dump_unreferenced_mem = 0;
> > +
> > + /*
> > + * REMIND: Still in development:
> > + * This may not be 100% stable on all ia64
> > + * memory banks. Accessing uncached memory
> > + * with cached accesses can cause subsequent
> > + * bus errors when the cache is flushed.
> > + */
> > + if (dump_level > DUMP_LEVEL_ALL_RAM)
> > + dump_nonconventional_mem = 1;
> > + else
> > + dump_nonconventional_mem = 0;
> > + break;
> > +
> > + /* get dump_level */
> > + case DIOGDUMPLEVEL:
> > + return (put_user((long)dump_level, (long *)arg));
> > +
> > + /* set dump_flags */
> > + case DIOSDUMPFLAGS:
> > + /* check flags */
> > + if (!(f->f_flags & O_RDWR))
> > + return (-EPERM);
> > +
> > + /* make sure we have a positive value */
> > + if (arg < 0)
> > + return (-EINVAL);
> > +
> > + dump_flags = (int)arg;
> > + break;
> > +
> > + /* get dump_flags */
> > + case DIOGDUMPFLAGS:
> > + return (put_user((long)dump_flags, (long *)arg));
> > +
> > + /* set the dump_compress status */
> > + case DIOSDUMPCOMPRESS:
> > + /* check flags */
> > + if (!(f->f_flags & O_RDWR))
> > + return (-EPERM);
> > +
> > + return (dump_compress_init((int)arg));
> > +
> > + /* get the dump_compress status */
> > + case DIOGDUMPCOMPRESS:
> > + return (put_user((long)dump_compress, (long *)arg));
> > +
> > + }
> > + return (0);
>
> I don't think ioctl is the right interface. Most of those want to be sysctls.
When can sysctls be set up? Earlier that ioctls() can be used? Perhaps
something very early in startup should be used; like kernel boot
options.
>
> > +/*
> > + * Name: dump_open()
> > + * Func: Open the dump device for use when the system crashes.
> > + */
> > +static int
> > +dump_open(struct inode *i, struct file *f)
> > +{
> > + /* opening a device is straightforward -- nothing to do here */
> > + return (0);
> > +}
>
> Remove it.
>
> > +/*
> > + * Name: dump_init()
> > + * Func: Initialize the dump process. This will set up any architecture
> > + * dependent code. The big key is we need the memory offsets before
> > + * the page table is initialized, because the base memory offset
> > + * is changed after paging_init() is called.
> > + */
> > +int __init
> > +dump_init(void)
>
> static
>
> > +{
> > + struct sysinfo info;
> > + int i;
> > +
> > + /* try to initialize /proc interfaces */
> > + if (dump_proc_init() < 0) {
> > + DUMP_PRINTF("dump_proc_init failed!; dump not initialized\n");
> > + return (-EBUSY);
> > + }
> > +
> > + /* try to create our dump device */
> > + if (register_chrdev(DUMP_MAJOR, "dump", &dump_fops)) {
> > + DUMP_PRINTF("cannot register dump character device!\n");
> > + return (-EBUSY);
> > + }
> > +
> > + /* initialize the dump headers to zero */
> > + memset(&dump_header, 0, sizeof(dump_header));
> > + memset(&dump_header_asm, 0, sizeof(dump_header_asm));
> > +
> > +#if !defined(CONFIG_DISCONTIGMEM) && !defined(CONFIG_IA64)
> > + /*
> > + * CONFIG_DISCONTIGMEM and CONFIG_IA64 systems are responsible
> > + * for initializing dump_mbank[] in __dump_init().
> > + */
> > + dump_mbanks = 1;
> > + dump_mbank[0].start = 0;
> > + dump_mbank[0].end = (((u64) max_mapnr) << PAGE_SHIFT) - 1;
> > + dump_mbank[0].type = DUMP_MBANK_TYPE_CONVENTIONAL_MEMORY;
> > +#endif
>
> Just move it to arch code for everyone.
What's wrong with having code which is common for most
arch's in the dump driver. Seems to me it keeps things
easier to understand. With ia64 being the only arch
with special needs, it seems cleaner to just have common
code handle the common situation.
>
> > +void __exit
> > +dump_cleanup(void)
>
> static
>
> > + /* try to create our dump device */
> > + if (unregister_chrdev(DUMP_MAJOR, "dump"))
> > + DUMP_PRINT("cannot unregister dump character device!\n");
>
> the printk is rather pointless..
Why is that?
>
> > +#ifdef MODULE
> > +#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,4,16))
> > +#if !defined(MODULE_LICENSE)
> > +#define MODULE_LICENSE(str)
> > +#endif
> > +#endif
>
> kill this ifdef junk.
>
> > +
> > +#define DUMP_MODULE_NAME "dump_blockdev"
>
> doesn't seem to be used.
>
> > +
> > +/*
> > + * -----------------------------------------------------------------------
> > + * V A R I A B L E S
> > + * -----------------------------------------------------------------------
> > + */
> > +kdev_t dump_dev; /* the actual kdev_t device number */
>
> didn't we already have this one in dump_base.c?
I thought this is dump_base.c
>
> > +void *dump_page_buffer; /* dump page buffer for memcpy()! */
> > +int dump_blk_size; /* sector size for dump_device */
> > +int dump_blk_shift; /* shift need to convert to sector size */
> > +struct bio *dump_bio; /* bio structure for io request */
> > +loff_t dump_offset; /* the offset in the output device */
> > +struct block_device *dump_bdev = NULL;
> > +unsigned long dumpdev_limit; /* the size limit of the block device */
> > +volatile int bio_complete = 1;/* Indicates the completion of each bio request */
> > +int dump_io_abort = 0; /* set by end_io routine during io error */
>
> Shouldn't much of this be static? again volatile is seldomly a good idea.
I suppose with 'bio_complete' being an int changing it's value is
atomic as long as it's treated a a volatile.Using a spinlock might
be cleaner.
>
> > +static void
> > +dump_free_bio(void)
> > +{
> > + if (dump_bio && dump_bio->bi_io_vec)
> > + kfree(dump_bio->bi_io_vec);
> > + if (dump_bio)
> > + kfree(dump_bio);
> > +}
>
> kfree(NULL) is fine.
>
> > +/*
> > + * Name: dump_open_kdev()
> > + * Func: Try to open the kdev_t argument as the real dump device.
> > + * This is where all the work is done for setting up the dump
> > + * device. It's assumed at this point that by passing in the
> > + * dump device's major/minor number, we can open it up, check
> > + * it out, and use it for whatever purposes.
> > + */
> > +static int
> > +dump_open_kdev(kdev_t tmp_dump_device)
>
> Should take a dev_t.
>
> > + /* release earlier dump_bdev if present */
> > + if (dump_bdev) {
> > + blkdev_put(dump_bdev, BDEV_RAW);
> > + dump_bdev = NULL;
> > + }
>
> Shouldn't this have gone away in ->close?
>
> > +
> > + dump_bdev = bdget(kdev_t_to_nr(tmp_dump_device));
> > + if (!dump_bdev) {
> > + retval = -ENODEV;
> > + goto err;
> > + }
> > +
> > + if (blkdev_get(dump_bdev, O_RDWR | O_LARGEFILE, 0, BDEV_RAW)) {
> > + retval = -ENODEV;
> > + goto err1;
> > + }
>
> bd_claim is missing
>
> > +
> > + if ((dump_page_buffer== (void *)NULL)) {
>
> (void *)NULL) is silly
>
> > + retval = -EINVAL;
> > + goto err2;
> > + }
> > +
> > + if (dump_bio)
> > + dump_free_bio();
> > +
> > + if ((dump_bio = kmalloc(sizeof(struct bio), GFP_KERNEL)) == NULL) {
> > + DUMP_PRINTF("Cannot allocate bio\n");
> > + retval = -ENOMEM;
> > + goto err2;
> > + }
>
> Shouldn't you use the generic bio allocator?
>
> > +static int
> > +dev_dump_ioctl(unsigned int cmd, unsigned long arg)
> > +{
> > + int ret = 0;
> > +
> > + /*
> > + * This is the main mechanism for controlling get/set data
> > + * for various dump device parameters. The real trick here
> > + * is setting the dump device (DIOSDUMPDEV). That's what
> > + * triggers everything else.
> > + */
> > + switch (cmd) {
> > + case DIOSDUMPDEV:
> > + ret = dump_open_kdev(to_kdev_t((dev_t)arg));
> > + break;
> > + case DIOSDUMPMEM:
> > + dump_page_buffer = (void *)arg;
> > + break;
> > + default:
> > + break;
> > +
> > + }
> > + return (ret);
> > +}
>
> ioctl is not a replacement for sane interfaces again!
>
> > +static struct dump_operations dump_blockdev_ops = {
> > + dump_open: dev_dump_open,
> > + dump_release: dev_dump_release,
> > + dump_ioctl: dev_dump_ioctl,
> > + dump_write: dev_dump_write,
> > + dump_seek: dev_dump_seek,
> > + dump_start: dev_dump_start,
> > + dump_end: dev_dump_end,
> > + dump_ready: dev_dump_ready,
> > +};
>
> Indentation seems strange, wants C99 initializers.
>
> > +int __init
> > +dump_blockdev_init(void)
>
> static
>
> > +{
> > + dump_page_buffer = NULL;
> > + dump_offset = 0;
>
> .bbs is per-zeroed.
>
> > +void __exit
> > +dump_blockdev_cleanup(void)
>
> static.
>
> > +#ifdef MODULE
> > +#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,4,16))
> > +#if !defined(MODULE_LICENSE)
> > +#define MODULE_LICENSE(str)
> > +#endif
> > +#endif
> > +
> > +MODULE_AUTHOR("Mohamed. Abbas");
> > +MODULE_DESCRIPTION("Block Device Driver for Linux Kernel Crash Dump (LKCD)");
> > +#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,16))
> > +MODULE_LICENSE("GPL");
> > +#endif
> > +#endif /* MODULE */
>
> more ifdef-crap to kill.
>
> > + int i;
> > + void *ptr;
> > +
> > + if (dump_header_asm.dha_stack[0])
> > + return 0;
> > +
> > + ptr = vmalloc(THREAD_SIZE * num_online_cpus());
> > + if (!ptr) {
>
> very strange indention..
>
> > +typedef struct _dump_header_asm_s {
>
> Please DON'T do typedefs. just struct _dump_header_asm!
>
> > + /* the dump magic number -- unique to verify dump is valid */
> > + uint64_t dha_magic_number;
>
> u64 & co
>
> > +#ifdef __KERNEL__
>
> kernel/user headers usually aren't shared..
>
> > +/* define TRUE and FALSE for use in our dump modules */
> > +#ifndef FALSE
> > +#define FALSE 0
> > +#endif
> > +
> > +#ifndef TRUE
> > +#define TRUE 1
> > +#endif
>
> Please just use 0/1 like evreryone else.
>
> > +#if DUMP_DEBUG
> > +void dump_bp(void); /* Called when something exceptional occurs */
> > +#define DUMP_BP() dump_bp() /* Breakpoint */
> > +#else
> > +#define DUMP_BP()
> > +#endif
>
> It doesn't look like this actually works.
It works; I used it while debugging the ia64 port.
>
> > +/* necessary header definitions in all cases */
> > +#define DUMP_KIOBUF_NUMBER 0xdeadbeef /* special number for kiobuf maps */
>
> kiobufs are gone in 2.5.44.
>
> > +typedef struct dump_mbank {
> > + u64 start;
> > + u64 end;
> > + int type;
> > + int pad1;
> > + long pad2;
> > +} dump_mbank_t;
>
> identation is once again rather strange.
>
> > +#ifndef KERNEL_VERSION
> > +#define KERNEL_VERSION(a,b,c) (((a) << 16) | ((b) << 8) | (c))
> > +#endif
>
> kill this.
>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
--
piet@www.piet.net
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH] 2.5.44: lkcd (9/9): dump driver and build files
2002-10-21 22:06 ` Piet Delaney
@ 2002-10-22 18:47 ` Christoph Hellwig
2002-10-22 11:57 ` Keith Owens
2002-10-22 16:49 ` Matt D. Robinson
0 siblings, 2 replies; 16+ messages in thread
From: Christoph Hellwig @ 2002-10-22 18:47 UTC (permalink / raw)
To: Piet Delaney; +Cc: Matt D. Robinson, linux-kernel, Keith Owens, steiner, jeremy
On Mon, Oct 21, 2002 at 03:06:59PM -0700, Piet Delaney wrote:
> > Using volatile is almost always a bug. USe atomic variables
> > or bitops instead.
>
> Yea, volatile is just being used to implement a simple atomic variable.
It just isn't guaranteed to be atomic.. Use atomic_t (for actual
values) or unsigned long + set_bit/test_bit/ænd friends for bitmasks.
> > > +static dump_compress_t dump_none_compression = {
> > > + compress_type: DUMP_COMPRESS_NONE,
> > > + compress_func: dump_compress_none,
> > > +};
> >
> > C99 initializers.
>
> What's C99?
.name = value, i.e. in this case:
static dump_compress_t dump_none_compression = {
.compress_type = DUMP_COMPRESS_NONE,
.compress_func = dump_compress_none,
};
> > > +#if DUMP_DEBUG
> > > +void dump_bp(void) {}
> > > +#endif
> >
> > Doesn't seem to be implemented at all.
>
> .
> dump_bp() is just a debugging hook that's
> enabled while debugging the lkcd dump driver.
> DUMP_DEBUG can be defined in dump.h and allows
> the kernel and user space code to be instrumented
> for easier debugging. I found it useful while debugging.
Well, I can't find dump_bp beeing implemented at all.
> Perhaps the usefulness of the various aproaches during early startup
> should be considered. In RedHat 8.0 there does seem to be existant
> hooks for user space core dumps in /etc/sysctl.conf:
> ----------------------------------------------------------------------
> Controls whether core dumps will append the PID to the core filename.
> # Useful for debugging multi-threaded applications.
> kernel.core_uses_pid =
> ----------------------------------------------------------------------
> When is /etc/sysctl.conf read by the kernel?
It isn't. Ths userspace tool sysctl reads it if asked to. It's done
in /etc/init.d/network by redhat. But you can uses systcl with a config
file or directly specified parameters at any time you want - or just
write to the /proc/sys/* files (which is what sysctl does internally).
> It's a callback used by the dump driver. These callbacks are
> used by disk drivers, like the SGI SCSI driver, to tune the
> dump driver for it's needs. The callback facility was added
> to the dump driver and this tuning for the device driver seemed
> like a natural user of the facility.
IMHO we should not have that code in the mainline kernel unless
uses. And personally I can't see any reason why xscsi should be
ported to 2.6, although of course I can't don't know what plans
that team has nor do I know about any managment decisions.
> > Yuck. Please just declare page_is_ram for every port.
> >
> > > +#if !defined(CONFIG_DISCONTIGMEM) && !defined(CONFIG_IA64)
> > > + p = (struct page *) &(mem_map[page_index]);
> >
> > Yuck. Please don't use mem_map in common code.
>
> Yea the NUMA Ia64 code can't use it; I dind't see
> and easy way of replacing it. What do you suggest?
There is a node_mem_map in each pgdat_t - that's what the common
code uses nowdays.
> > Why don't you do this
>
> Perhaps it could. Perhaps kern_addr_valid() doesn't work for ia64.
> I'd have to check to be sure.
It should work on any architecture. Once you're in mainline thay
just have to fix it if it doesn't :)
> > I don't think ioctl is the right interface. Most of those want to be sysctls.
>
> When can sysctls be set up? Earlier that ioctls() can be used? Perhaps
> something very early in startup should be used; like kernel boot
> options.
sysctl by number is a syscall and can be used at any time. sysctl
by name needs procfs mounted. And of course you driver must either
in the kernel or the module loaded so that the entries are actually
registered.
> >
> > Just move it to arch code for everyone.
>
> What's wrong with having code which is common for most
> arch's in the dump driver. Seems to me it keeps things
> easier to understand. With ia64 being the only arch
> with special needs, it seems cleaner to just have common
> code handle the common situation.
ifdefs in common code make reading it a lot harder, and per-arch
ifdefs are a maintaince horror. Maybe introduce a __ARCH_DUMP_MBANK
in asm-ia64/dump.h instead so any new arch can plug in easily?
> > > + /* try to create our dump device */
> > > + if (unregister_chrdev(DUMP_MAJOR, "dump"))
> > > + DUMP_PRINT("cannot unregister dump character device!\n");
> >
> > the printk is rather pointless..
>
> Why is that?
Because the module will be unloaded anyway - i.e. the admin can do
anything at all if it failed. For the given arguments it can't
return an error anyway - I think we should change it to void return
for 2.6..
> > > +kdev_t dump_dev; /* the actual kdev_t device number */
> >
> > didn't we already have this one in dump_base.c?
> I thought this is dump_base.c
Exactly the same line is in dump_base.c and dump_blockdev.c.
> > Shouldn't much of this be static? again volatile is seldomly a good idea.
>
> I suppose with 'bio_complete' being an int changing it's value is
> atomic as long as it's treated a a volatile.Using a spinlock might
> be cleaner.
an atomic_t or set_bit/test_bit/etc is used to be atomic in the kernel
if you don't want a lock. And in this case a lock looks like overkill.
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH] 2.5.44: lkcd (9/9): dump driver and build files
2002-10-22 18:47 ` Christoph Hellwig
@ 2002-10-22 11:57 ` Keith Owens
2002-10-22 22:21 ` Piet Delaney
2002-10-22 16:49 ` Matt D. Robinson
1 sibling, 1 reply; 16+ messages in thread
From: Keith Owens @ 2002-10-22 11:57 UTC (permalink / raw)
To: Christoph Hellwig
Cc: Piet Delaney, Matt D. Robinson, linux-kernel, steiner, jeremy
On Tue, 22 Oct 2002 14:47:45 -0400,
Christoph Hellwig <hch@sgi.com> wrote:
>On Mon, Oct 21, 2002 at 03:06:59PM -0700, Piet Delaney wrote:
>> > Using volatile is almost always a bug. USe atomic variables
>> > or bitops instead.
>>
>> Yea, volatile is just being used to implement a simple atomic variable.
>
>It just isn't guaranteed to be atomic.. Use atomic_t (for actual
>values) or unsigned long + set_bit/test_bit/ænd friends for bitmasks.
atomic_t is problematic for debugging code which can be invoked by an
error from any state. On parisc, atomic_add is implemented using load
and clear on a hash of the lock address, so it is possible to get
collisions on locks when doing atomic ops from debugging code.
Especially when the parisc code in 2.5.44 has exactly one hash table
entry. kdb has the same problem and tries to avoid atomic_t for the
same reason, the current state is unreliable.
The dump_in_progress flag is set in one place and cleared in another.
All the other uses of dump_in_progress are testing its state. If
atomic_t cannot be used safely, then it must be defined as volatile.
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH] 2.5.44: lkcd (9/9): dump driver and build files
2002-10-22 11:57 ` Keith Owens
@ 2002-10-22 22:21 ` Piet Delaney
2002-10-22 22:56 ` Keith Owens
0 siblings, 1 reply; 16+ messages in thread
From: Piet Delaney @ 2002-10-22 22:21 UTC (permalink / raw)
To: Keith Owens
Cc: Christoph Hellwig, Matt D. Robinson, linux-kernel, steiner,
jeremy
On Tue, 2002-10-22 at 04:57, Keith Owens wrote:
> On Tue, 22 Oct 2002 14:47:45 -0400,
> Christoph Hellwig <hch@sgi.com> wrote:
> >On Mon, Oct 21, 2002 at 03:06:59PM -0700, Piet Delaney wrote:
> >> > Using volatile is almost always a bug. USe atomic variables
> >> > or bitops instead.
> >>
> >> Yea, volatile is just being used to implement a simple atomic variable.
> >
> >It just isn't guaranteed to be atomic.. Use atomic_t (for actual
> >values) or unsigned long + set_bit/test_bit/ænd friends for bitmasks.
>
> atomic_t is problematic for debugging code which can be invoked by an
> error from any state. On parisc, atomic_add is implemented using load
> and clear on a hash of the lock address, so it is possible to get
> collisions on locks when doing atomic ops from debugging code.
> Especially when the parisc code in 2.5.44 has exactly one hash table
> entry. kdb has the same problem and tries to avoid atomic_t for the
> same reason, the current state is unreliable.
>
> The dump_in_progress flag is set in one place and cleared in another.
> All the other uses of dump_in_progress are testing its state. If
> atomic_t cannot be used safely, then it must be defined as volatile.
atomic_read(v) and atomic_set(v,i) seem to be safe for most platforms.
Looks like your right, for parisc even these functions are using a
spinlock. Is it really necessary for parisc to use spinlocks? Even
Solaris doesn't use spinlocks for atomic set and reads of atomic
variables.
-piet
--
piet@www.piet.net
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH] 2.5.44: lkcd (9/9): dump driver and build files
2002-10-22 22:21 ` Piet Delaney
@ 2002-10-22 22:56 ` Keith Owens
0 siblings, 0 replies; 16+ messages in thread
From: Keith Owens @ 2002-10-22 22:56 UTC (permalink / raw)
To: Piet Delaney
Cc: Christoph Hellwig, Matt D. Robinson, linux-kernel, steiner,
jeremy
On 22 Oct 2002 15:21:02 -0700,
Piet Delaney <piet@www.piet.net> wrote:
>Looks like your right, for parisc even these functions are using a
>spinlock. Is it really necessary for parisc to use spinlocks? Even
>Solaris doesn't use spinlocks for atomic set and reads of atomic
>variables.
Hardware restriction. Somebody read that "all locks can be implemented
in terms of a single hardware primitive" and believed it :(. The only
atomic operation on parisc is load and clear word. According to the
comments in asm-parisc/atomic.h, atomic_set should not require a lock,
but it is coded to use one. Atomic add/sub obviously needs a lock.
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH] 2.5.44: lkcd (9/9): dump driver and build files
2002-10-22 18:47 ` Christoph Hellwig
2002-10-22 11:57 ` Keith Owens
@ 2002-10-22 16:49 ` Matt D. Robinson
1 sibling, 0 replies; 16+ messages in thread
From: Matt D. Robinson @ 2002-10-22 16:49 UTC (permalink / raw)
To: Christoph Hellwig
Cc: Piet Delaney, linux-kernel, Keith Owens, steiner, jeremy
On Tue, 22 Oct 2002, Christoph Hellwig wrote:
|>On Mon, Oct 21, 2002 at 03:06:59PM -0700, Piet Delaney wrote:
|>> > Shouldn't much of this be static? again volatile is seldomly a good idea.
|>>
|>> I suppose with 'bio_complete' being an int changing it's value is
|>> atomic as long as it's treated a a volatile.Using a spinlock might
|>> be cleaner.
|>
|>an atomic_t or set_bit/test_bit/etc is used to be atomic in the kernel
|>if you don't want a lock. And in this case a lock looks like overkill.
All of the volatile/atomic, C99, typedef, data format, return format,
u64/32/16/etc, are all addressed and fixed in the latest patches. The
dump_bp() is removed for now, to be considered later if/when it makes
sense.
We'd want to keep the ioctl() interface, given the number of programs
using it across multiple platforms (and is being considered for
multiple OSes). DUMP_MAJOR has changed to CRASH_DUMP_MAJOR and is
now standard in major.h. Finally, the MAINTAINERS and Config.help
files are updated.
We're correcting a few more issues with the mem_map[], page_is_ram(),
etc., usage, but those shouldn't take long.
If anyone needs a preliminary patch this morning, let me know.
--Matt
P.S. Pete, we can go through the dump_bp() stuff on the mailing list.
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH] 2.5.44: lkcd (9/9): dump driver and build files
2002-10-21 21:21 ` Christoph Hellwig
2002-10-21 19:07 ` Matt D. Robinson
2002-10-21 22:06 ` Piet Delaney
@ 2002-10-22 2:04 ` Nicholas Wourms
2002-10-22 5:45 ` Matt D. Robinson
2002-10-22 13:00 ` Christoph Hellwig
2002-10-22 15:05 ` Suparna Bhattacharya
3 siblings, 2 replies; 16+ messages in thread
From: Nicholas Wourms @ 2002-10-22 2:04 UTC (permalink / raw)
To: linux-kernel
Christoph Hellwig wrote:
> On Mon, Oct 21, 2002 at 03:16:05AM -0700, Matt D. Robinson wrote:
>> diff -Naur linux-2.5.44.orig/drivers/dump/Makefile
>> linux-2.5.44.lkcd/drivers/dump/Makefile
>> --- linux-2.5.44.orig/drivers/dump/Makefile Wed Dec 31 16:00:00 1969
>> +++ linux-2.5.44.lkcd/drivers/dump/Makefile Sat Oct 19 12:39:15 2002
>> @@ -0,0 +1,30 @@
>> +#
>> +# Makefile for the dump device drivers.
>> +#
>> +# 12 June 2000, Christoph Hellwig <schch@pe.tu-clausthal.de>
>> +# Rewritten by Matt D. Robinson (yakker@sourceforge.net) for
>> +# the dump directory.
>
> *cough* is that an old mail address and I can't even remember having
> touched that file.. :) What about remoing that note..
>
Didn't this used to be an SGI project? Perhaps that is where you might have
"touched" it.
Cheers,
Nicholas
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH] 2.5.44: lkcd (9/9): dump driver and build files
2002-10-22 2:04 ` Nicholas Wourms
@ 2002-10-22 5:45 ` Matt D. Robinson
2002-10-22 13:00 ` Christoph Hellwig
1 sibling, 0 replies; 16+ messages in thread
From: Matt D. Robinson @ 2002-10-22 5:45 UTC (permalink / raw)
To: Nicholas Wourms; +Cc: linux-kernel
On Mon, 21 Oct 2002, Nicholas Wourms wrote:
|>Christoph Hellwig wrote:
|>
|>> On Mon, Oct 21, 2002 at 03:16:05AM -0700, Matt D. Robinson wrote:
|>>> diff -Naur linux-2.5.44.orig/drivers/dump/Makefile
|>>> linux-2.5.44.lkcd/drivers/dump/Makefile
|>>> --- linux-2.5.44.orig/drivers/dump/Makefile Wed Dec 31 16:00:00 1969
|>>> +++ linux-2.5.44.lkcd/drivers/dump/Makefile Sat Oct 19 12:39:15 2002
|>>> @@ -0,0 +1,30 @@
|>>> +#
|>>> +# Makefile for the dump device drivers.
|>>> +#
|>>> +# 12 June 2000, Christoph Hellwig <schch@pe.tu-clausthal.de>
|>>> +# Rewritten by Matt D. Robinson (yakker@sourceforge.net) for
|>>> +# the dump directory.
|>>
|>> *cough* is that an old mail address and I can't even remember having
|>> touched that file.. :) What about remoing that note..
|>>
|>
|>Didn't this used to be an SGI project? Perhaps that is where you might have
|>"touched" it.
Because I used the base structure of another Makefile for making
mine, I carried over his name.
--Matt
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH] 2.5.44: lkcd (9/9): dump driver and build files
2002-10-22 2:04 ` Nicholas Wourms
2002-10-22 5:45 ` Matt D. Robinson
@ 2002-10-22 13:00 ` Christoph Hellwig
1 sibling, 0 replies; 16+ messages in thread
From: Christoph Hellwig @ 2002-10-22 13:00 UTC (permalink / raw)
To: Nicholas Wourms; +Cc: linux-kernel
On Mon, Oct 21, 2002 at 10:04:39PM -0400, Nicholas Wourms wrote:
> Didn't this used to be an SGI project? Perhaps that is where you might have
> "touched" it.
I wasn't at sgi at that time :) And I would certainly not have used
an university mail address..
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH] 2.5.44: lkcd (9/9): dump driver and build files
2002-10-21 21:21 ` Christoph Hellwig
` (2 preceding siblings ...)
2002-10-22 2:04 ` Nicholas Wourms
@ 2002-10-22 15:05 ` Suparna Bhattacharya
2002-10-22 9:49 ` Jens Axboe
3 siblings, 1 reply; 16+ messages in thread
From: Suparna Bhattacharya @ 2002-10-22 15:05 UTC (permalink / raw)
On Mon, 21 Oct 2002 19:43:20 +0530, Christoph Hellwig wrote:
>> +
>> + if ((dump_bio = kmalloc(sizeof(struct bio), GFP_KERNEL)) == NULL) { +
>> DUMP_PRINTF("Cannot allocate bio\n"); + retval = -ENOMEM;
>> + goto err2;
>> + }
>
> Shouldn't you use the generic bio allocator?
>
Not sure that this should come from the bio mempool. Objects
allocated from the mem pool are expected to be released back to
the pool within a reasonable period (after i/o is done), which is
not quite the case here.
Dump preallocates the bio early when configured and holds on to
it all through the time the system is up (avoids allocs at
actual dump time). Doesn't seem like the right thing to hold
on to a bio mempool element that long.
Regards
Suparna
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH] 2.5.44: lkcd (9/9): dump driver and build files
2002-10-22 15:05 ` Suparna Bhattacharya
@ 2002-10-22 9:49 ` Jens Axboe
2002-10-22 14:43 ` Randy.Dunlap
0 siblings, 1 reply; 16+ messages in thread
From: Jens Axboe @ 2002-10-22 9:49 UTC (permalink / raw)
To: Suparna Bhattacharya; +Cc: Linux Kernel
On Tue, Oct 22 2002, Suparna Bhattacharya wrote:
> On Mon, 21 Oct 2002 19:43:20 +0530, Christoph Hellwig wrote:
>
>
> >> +
> >> + if ((dump_bio = kmalloc(sizeof(struct bio), GFP_KERNEL)) == NULL) { +
> >> DUMP_PRINTF("Cannot allocate bio\n"); + retval = -ENOMEM;
> >> + goto err2;
> >> + }
> >
> > Shouldn't you use the generic bio allocator?
> >
>
> Not sure that this should come from the bio mempool. Objects
> allocated from the mem pool are expected to be released back to
> the pool within a reasonable period (after i/o is done), which is
> not quite the case here.
>
> Dump preallocates the bio early when configured and holds on to
> it all through the time the system is up (avoids allocs at
> actual dump time). Doesn't seem like the right thing to hold
> on to a bio mempool element that long.
Definitely, one must not use the bio pool for long term allocations.
--
Jens Axboe
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH] 2.5.44: lkcd (9/9): dump driver and build files
2002-10-22 9:49 ` Jens Axboe
@ 2002-10-22 14:43 ` Randy.Dunlap
2002-10-22 14:59 ` Jens Axboe
0 siblings, 1 reply; 16+ messages in thread
From: Randy.Dunlap @ 2002-10-22 14:43 UTC (permalink / raw)
To: Jens Axboe; +Cc: Suparna Bhattacharya, Linux Kernel
On Tue, 22 Oct 2002, Jens Axboe wrote:
| On Tue, Oct 22 2002, Suparna Bhattacharya wrote:
| > On Mon, 21 Oct 2002 19:43:20 +0530, Christoph Hellwig wrote:
| >
| >
| > >> +
| > >> + if ((dump_bio = kmalloc(sizeof(struct bio), GFP_KERNEL)) == NULL) { +
| > >> DUMP_PRINTF("Cannot allocate bio\n"); + retval = -ENOMEM;
| > >> + goto err2;
| > >> + }
| > >
| > > Shouldn't you use the generic bio allocator?
| > >
| >
| > Not sure that this should come from the bio mempool. Objects
| > allocated from the mem pool are expected to be released back to
| > the pool within a reasonable period (after i/o is done), which is
| > not quite the case here.
| >
| > Dump preallocates the bio early when configured and holds on to
| > it all through the time the system is up (avoids allocs at
| > actual dump time). Doesn't seem like the right thing to hold
| > on to a bio mempool element that long.
|
| Definitely, one must not use the bio pool for long term allocations.
"must not" ?
what happens if one does do that? [not suggesting doing that]
--
~Randy
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH] 2.5.44: lkcd (9/9): dump driver and build files
2002-10-22 14:43 ` Randy.Dunlap
@ 2002-10-22 14:59 ` Jens Axboe
0 siblings, 0 replies; 16+ messages in thread
From: Jens Axboe @ 2002-10-22 14:59 UTC (permalink / raw)
To: Randy.Dunlap; +Cc: Suparna Bhattacharya, Linux Kernel
On Tue, Oct 22 2002, Randy.Dunlap wrote:
> On Tue, 22 Oct 2002, Jens Axboe wrote:
>
> | On Tue, Oct 22 2002, Suparna Bhattacharya wrote:
> | > On Mon, 21 Oct 2002 19:43:20 +0530, Christoph Hellwig wrote:
> | >
> | >
> | > >> +
> | > >> + if ((dump_bio = kmalloc(sizeof(struct bio), GFP_KERNEL)) == NULL) { +
> | > >> DUMP_PRINTF("Cannot allocate bio\n"); + retval = -ENOMEM;
> | > >> + goto err2;
> | > >> + }
> | > >
> | > > Shouldn't you use the generic bio allocator?
> | > >
> | >
> | > Not sure that this should come from the bio mempool. Objects
> | > allocated from the mem pool are expected to be released back to
> | > the pool within a reasonable period (after i/o is done), which is
> | > not quite the case here.
> | >
> | > Dump preallocates the bio early when configured and holds on to
> | > it all through the time the system is up (avoids allocs at
> | > actual dump time). Doesn't seem like the right thing to hold
> | > on to a bio mempool element that long.
> |
> | Definitely, one must not use the bio pool for long term allocations.
>
> "must not" ?
Yes
> what happens if one does do that? [not suggesting doing that]
Well, the whole concept behind mempool and deadlock-free allocation
while doing io, builds on that if slab allocation fails we fall back to
a private pool. If allocation from the private pool also fails, then we
_know_ we have io in progress that will finish "shortly". This is what
makes it safe to sleep on the private pool. Once you start doing long
term allocations from the bio pool, we can no longer make this
guarentee.
--
Jens Axboe
^ permalink raw reply [flat|nested] 16+ messages in thread
end of thread, other threads:[~2002-10-22 22:50 UTC | newest]
Thread overview: 16+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2002-10-21 10:16 [PATCH] 2.5.44: lkcd (9/9): dump driver and build files Matt D. Robinson
2002-10-21 21:21 ` Christoph Hellwig
2002-10-21 19:07 ` Matt D. Robinson
2002-10-21 22:06 ` Piet Delaney
2002-10-22 18:47 ` Christoph Hellwig
2002-10-22 11:57 ` Keith Owens
2002-10-22 22:21 ` Piet Delaney
2002-10-22 22:56 ` Keith Owens
2002-10-22 16:49 ` Matt D. Robinson
2002-10-22 2:04 ` Nicholas Wourms
2002-10-22 5:45 ` Matt D. Robinson
2002-10-22 13:00 ` Christoph Hellwig
2002-10-22 15:05 ` Suparna Bhattacharya
2002-10-22 9:49 ` Jens Axboe
2002-10-22 14:43 ` Randy.Dunlap
2002-10-22 14:59 ` Jens Axboe
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