[PATCH 0/8] pseries: phyp dump: hypervisor-assisted dump

[PATCH 0/8] pseries: phyp dump: hypervisor-assisted dump

[Manish Ahuja]

The following series of patches implement a basic framework
for hypervisor-assisted dump. The very first patch provides 
documentation explaining what this is    :-)   . Yes, its supposed
to be an improvement over kdump.

A list of open issues / todo list is included in the documentation.
It also appears that the not-yet-released firmware versions this was tested 
on are still, ahem, incomplete; this work is also pending.

I have included most of the changes requested. Although, I did find
one or two, fixed in a later patch file rather than the first location
they appeared at.

-- Manish & Linas.

[PATCH 1/8] pseries: phyp dump: Docmentation

[Manish Ahuja]

Basic documentation for hypervisor-assisted dump.

Signed-off-by: Linas Vepstas <linasvepstas@gmail.com>
Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>

----
 Documentation/powerpc/phyp-assisted-dump.txt |  129 +++++++++++++++++++++++++++
 1 file changed, 129 insertions(+)

Index: 2.6.24-rc5/Documentation/powerpc/phyp-assisted-dump.txt
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ 2.6.24-rc5/Documentation/powerpc/phyp-assisted-dump.txt	2008-01-07 18:05:46.000000000 -0600
@@ -0,0 +1,129 @@
+
+                   Hypervisor-Assisted Dump
+                   ------------------------
+                       November 2007
+
+The goal of hypervisor-assisted dump is to enable the dump of
+a crashed system, and to do so from a fully-reset system, and
+to minimize the total elapsed time until the system is back
+in production use.
+
+As compared to kdump or other strategies, hypervisor-assisted
+dump offers several strong, practical advantages:
+
+-- Unlike kdump, the system has been reset, and loaded
+   with a fresh copy of the kernel.  In particular,
+   PCI and I/O devices have been reinitialized and are
+   in a clean, consistent state.
+-- As the dump is performed, the dumped memory becomes
+   immediately available to the system for normal use.
+-- After the dump is completed, no further reboots are
+   required; the system will be fully usable, and running
+   in it's normal, production mode on it normal kernel.
+
+The above can only be accomplished by coordination with,
+and assistance from the hypervisor. The procedure is
+as follows:
+
+-- When a system crashes, the hypervisor will save
+   the low 256MB of RAM to a previously registered
+   save region. It will also save system state, system
+   registers, and hardware PTE's.
+
+-- After the low 256MB area has been saved, the
+   hypervisor will reset PCI and other hardware state.
+   It will *not* clear RAM. It will then launch the
+   bootloader, as normal.
+
+-- The freshly booted kernel will notice that there
+   is a new node (ibm,dump-kernel) in the device tree,
+   indicating that there is crash data available from
+   a previous boot. It will boot into only 256MB of RAM,
+   reserving the rest of system memory.
+
+-- Userspace tools will parse /sys/kernel/release_region
+   and read /proc/vmcore to obtain the contents of memory,
+   which holds the previous crashed kernel. The userspace
+   tools may copy this info to disk, or network, nas, san,
+   iscsi, etc. as desired.
+
+   For Example: the values in /sys/kernel/release-region
+   would look something like this (address-range pairs).
+   CPU:0x177fee000-0x10000: HPTE:0x177ffe020-0x1000: /
+   DUMP:0x177fff020-0x10000000, 0x10000000-0x16F1D370A
+
+-- As the userspace tools complete saving a portion of
+   dump, they echo an offset and size to
+   /sys/kernel/release_region to release the reserved
+   memory back to general use.
+
+   An example of this is:
+     "echo 0x40000000 0x10000000 > /sys/kernel/release_region"
+   which will release 256MB at the 1GB boundary.
+
+Please note that the hypervisor-assisted dump feature
+is only available on Power6-based systems with recent
+firmware versions.
+
+Implementation details:
+----------------------
+In order for this scheme to work, memory needs to be reserved
+quite early in the boot cycle. However, access to the device
+tree this early in the boot cycle is difficult, and device-tree
+access is needed to determine if there is a crash data waiting.
+To work around this problem, all but 256MB of RAM is reserved
+during early boot. A short while later in boot, a check is made
+to determine if there is dump data waiting. If there isn't,
+then the reserved memory is released to general kernel use.
+If there is dump data, then the /sys/kernel/release_region
+file is created, and the reserved memory is held.
+
+If there is no waiting dump data, then all but 256MB of the
+reserved ram will be released for general kernel use. The
+highest 256 MB of RAM will *not* be released: this region
+will be kept permanently reserved, so that it can act as
+a receptacle for a copy of the low 256MB in the case a crash
+does occur. See, however, "open issues" below, as to whether
+such a reserved region is really needed.
+
+Currently the dump will be copied from /proc/vmcore to a
+a new file upon user intervention. The starting address
+to be read and the range for each data point in provided
+in /sys/kernel/release_region.
+
+The tools to examine the dump will be same as the ones
+used for kdump.
+
+
+General notes:
+--------------
+Security: please note that there are potential security issues
+with any sort of dump mechanism. In particular, plaintext
+(unencrypted) data, and possibly passwords, may be present in
+the dump data. Userspace tools must take adequate precautions to
+preserve security.
+
+Open issues/ToDo:
+------------
+ o The various code paths that tell the hypervisor that a crash
+   occurred, vs. it simply being a normal reboot, should be
+   reviewed, and possibly clarified/fixed.
+
+ o Instead of using /sys/kernel, should there be a /sys/dump
+   instead? There is a dump_subsys being created by the s390 code,
+   perhaps the pseries code should use a similar layout as well.
+
+ o Is reserving a 256MB region really required? The goal of
+   reserving a 256MB scratch area is to make sure that no
+   important crash data is clobbered when the hypervisor
+   save low mem to the scratch area. But, if one could assure
+   that nothing important is located in some 256MB area, then
+   it would not need to be reserved. Something that can be
+   improved in subsequent versions.
+
+ o Still working the kdump team to integrate this with kdump,
+   some work remains but this would not affect the current
+   patches.
+
+ o Still need to write a shell script, to copy the dump away.
+   Currently I am parsing it manually.

[PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Manish Ahuja]

Initial patch for reserving memory in early boot, and freeing it later.
If the previous boot had ended with a crash, the reserved memory would contain
a copy of the crashed kernel data.

Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
Signed-off-by: Linas Vepstas <linas@austin.ibm.com>

----
 arch/powerpc/kernel/prom.c                 |   46 ++++++++++++++++++
 arch/powerpc/kernel/rtas.c                 |   27 +++++++++++
 arch/powerpc/platforms/pseries/Makefile    |    1 
 arch/powerpc/platforms/pseries/phyp_dump.c |   71 +++++++++++++++++++++++++++++
 include/asm-powerpc/phyp_dump.h            |   37 +++++++++++++++
 include/asm/rtas.h                         |    3 +
 6 files changed, 185 insertions(+)

Index: 2.6.24-rc5/include/asm-powerpc/phyp_dump.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ 2.6.24-rc5/include/asm-powerpc/phyp_dump.h	2008-01-18 07:37:33.000000000 -0600
@@ -0,0 +1,37 @@
+/*
+ * Hypervisor-assisted dump
+ *
+ * Linas Vepstas, Manish Ahuja 2007
+ * Copyright (c) 2007 IBM Corp.
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _PPC64_PHYP_DUMP_H
+#define _PPC64_PHYP_DUMP_H
+
+#ifdef CONFIG_PHYP_DUMP
+
+/* The RMR region will be saved for later dumping
+ * whenever the kernel crashes. Set this to 256MB. */
+#define PHYP_DUMP_RMR_START 0x0
+#define PHYP_DUMP_RMR_END   (1UL<<28)
+
+struct phyp_dump {
+	/* Memory that is reserved during very early boot. */
+	unsigned long init_reserve_start;
+	unsigned long init_reserve_size;
+	/* Check status during boot if dump active & present*/
+	unsigned long phyp_dump_is_active;
+	/* store cpu & hpte size */
+	unsigned long cpu_state_size;
+	unsigned long hpte_region_size;
+};
+
+extern struct phyp_dump *phyp_dump_info;
+
+#endif /* CONFIG_PHYP_DUMP */
+#endif /* _PPC64_PHYP_DUMP_H */
Index: 2.6.24-rc5/arch/powerpc/platforms/pseries/phyp_dump.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ 2.6.24-rc5/arch/powerpc/platforms/pseries/phyp_dump.c	2008-01-18 07:37:33.000000000 -0600
@@ -0,0 +1,71 @@
+/*
+ * Hypervisor-assisted dump
+ *
+ * Linas Vepstas, Manish Ahuja 2007
+ * Copyrhgit (c) 2007 IBM Corp.
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/pfn.h>
+#include <linux/swap.h>
+
+#include <asm/page.h>
+#include <asm/phyp_dump.h>
+
+/* Global, used to communicate data between early boot and late boot */
+static struct phyp_dump phyp_dump_global;
+struct phyp_dump *phyp_dump_info = &phyp_dump_global;
+
+/**
+ * release_memory_range -- release memory previously lmb_reserved
+ * @start_pfn: starting physical frame number
+ * @nr_pages: number of pages to free.
+ *
+ * This routine will release memory that had been previously
+ * lmb_reserved in early boot. The released memory becomes
+ * available for genreal use.
+ */
+static void
+release_memory_range(unsigned long start_pfn, unsigned long nr_pages)
+{
+	struct page *rpage;
+	unsigned long end_pfn;
+	long i;
+
+	end_pfn = start_pfn + nr_pages;
+
+	for (i=start_pfn; i <= end_pfn; i++) {
+		rpage = pfn_to_page(i);
+		if (PageReserved(rpage)) {
+			ClearPageReserved(rpage);
+			init_page_count(rpage);
+			__free_page(rpage);
+			totalram_pages++;
+		}
+	}
+}
+
+static int __init phyp_dump_setup(void)
+{
+	unsigned long start_pfn, nr_pages;
+
+	/* If no memory was reserved in early boot, there is nothing to do */
+	if (phyp_dump_info->init_reserve_size == 0)
+		return 0;
+
+	/* Release memory that was reserved in early boot */
+	start_pfn = PFN_DOWN(phyp_dump_info->init_reserve_start);
+	nr_pages = PFN_DOWN(phyp_dump_info->init_reserve_size);
+	release_memory_range(start_pfn, nr_pages);
+
+	return 0;
+}
+
+subsys_initcall(phyp_dump_setup);
Index: 2.6.24-rc5/arch/powerpc/platforms/pseries/Makefile
===================================================================
--- 2.6.24-rc5.orig/arch/powerpc/platforms/pseries/Makefile	2008-01-18 07:37:28.000000000 -0600
+++ 2.6.24-rc5/arch/powerpc/platforms/pseries/Makefile	2008-01-18 07:37:33.000000000 -0600
@@ -18,3 +18,4 @@ obj-$(CONFIG_HOTPLUG_CPU)	+= hotplug-cpu
 obj-$(CONFIG_HVC_CONSOLE)	+= hvconsole.o
 obj-$(CONFIG_HVCS)		+= hvcserver.o
 obj-$(CONFIG_HCALL_STATS)	+= hvCall_inst.o
+obj-$(CONFIG_PHYP_DUMP)	+= phyp_dump.o
Index: 2.6.24-rc5/arch/powerpc/kernel/prom.c
===================================================================
--- 2.6.24-rc5.orig/arch/powerpc/kernel/prom.c	2008-01-18 07:37:28.000000000 -0600
+++ 2.6.24-rc5/arch/powerpc/kernel/prom.c	2008-01-18 07:37:33.000000000 -0600
@@ -51,6 +51,7 @@
 #include <asm/machdep.h>
 #include <asm/pSeries_reconfig.h>
 #include <asm/pci-bridge.h>
+#include <asm/phyp_dump.h>
 #include <asm/kexec.h>
 
 #ifdef DEBUG
@@ -1011,6 +1012,48 @@ static void __init early_reserve_mem(voi
 #endif
 }
 
+#ifdef CONFIG_PHYP_DUMP
+
+/**
+ * reserve_crashed_mem() - reserve all not-yet-dumped mmemory
+ *
+ * This routine will reserve almost all of the memory in the
+ * system, except for a few hundred megabytes used to boot the
+ * new kernel. As the reserved memory is dumped to the dump
+ * device (by userland tools), it will be freed and made available.
+ */
+static void __init reserve_crashed_mem(void)
+{
+	unsigned long base, size;
+
+	if (phyp_dump_info->phyp_dump_is_active) {
+		/* Reserve *everything* above RMR. We'll free this real soon.*/
+		base = PHYP_DUMP_RMR_END;
+		size = lmb_end_of_DRAM() - base;
+
+		/* XXX crashed_ram_end is wrong, since it may be beyond
+	 	* the memory_limit, it will need to be adjusted. */
+		lmb_reserve(base, size);
+
+		phyp_dump_info->init_reserve_start = base;
+		phyp_dump_info->init_reserve_size = size;
+	}
+	else {
+		size = phyp_dump_info->cpu_state_size +
+			phyp_dump_info->hpte_region_size +
+			PHYP_DUMP_RMR_END;
+		base = lmb_end_of_DRAM() - size;
+	printk(KERN_ERR "Manish reserve regular kernel space is %ld %ld\n", base, size);
+		lmb_reserve(base, size);
+		phyp_dump_info->init_reserve_start = base;
+		phyp_dump_info->init_reserve_size = size;
+	}
+}
+#else
+static inline void __init reserve_crashed_mem(void) {}
+#endif /* CONFIG_PHYP_DUMP */
+
+
 void __init early_init_devtree(void *params)
 {
 	DBG(" -> early_init_devtree(%p)\n", params);
@@ -1022,6 +1065,8 @@ void __init early_init_devtree(void *par
 	/* Some machines might need RTAS info for debugging, grab it now. */
 	of_scan_flat_dt(early_init_dt_scan_rtas, NULL);
 #endif
+	/* scan tree to see if dump occured during last boot */
+	of_scan_flat_dt(early_init_dt_scan_phyp_dump, NULL);
 
 	/* Retrieve various informations from the /chosen node of the
 	 * device-tree, including the platform type, initrd location and
@@ -1043,6 +1088,7 @@ void __init early_init_devtree(void *par
 	reserve_kdump_trampoline();
 	reserve_crashkernel();
 	early_reserve_mem();
+	reserve_crashed_mem();
 
 	lmb_enforce_memory_limit(memory_limit);
 	lmb_analyze();
Index: 2.6.24-rc5/arch/powerpc/kernel/rtas.c
===================================================================
--- 2.6.24-rc5.orig/arch/powerpc/kernel/rtas.c	2008-01-18 07:37:28.000000000 -0600
+++ 2.6.24-rc5/arch/powerpc/kernel/rtas.c	2008-01-18 07:37:33.000000000 -0600
@@ -39,6 +39,7 @@
 #include <asm/syscalls.h>
 #include <asm/smp.h>
 #include <asm/atomic.h>
+#include <asm/phyp_dump.h>
 
 struct rtas_t rtas = {
 	.lock = SPIN_LOCK_UNLOCKED
@@ -883,6 +884,32 @@ void __init rtas_initialize(void)
 #endif
 }
 
+int __init early_init_dt_scan_phyp_dump(unsigned long node,
+		const char *uname, int depth, void *data)
+{
+#ifdef CONFIG_PHYP_DUMP
+	const unsigned int *sizes;
+
+	phyp_dump_info->phyp_dump_is_active = 0;
+	if (depth != 1 || strcmp(uname, "rtas") != 0)
+		return 0;
+
+	if (of_get_flat_dt_prop(node, "ibm,dump-kernel", NULL))
+		phyp_dump_info->phyp_dump_is_active++;
+
+	sizes = of_get_flat_dt_prop(node, "ibm,configure-kernel-dump-sizes", NULL);
+	if (!sizes)
+		return 0;
+
+	if (sizes[0] == 1)
+		phyp_dump_info->cpu_state_size = *((unsigned long *)&sizes[1]);
+
+	if (sizes[3] == 2)
+		phyp_dump_info->hpte_region_size = *((unsigned long *)&sizes[4]);
+#endif
+	return 1;
+}
+
 int __init early_init_dt_scan_rtas(unsigned long node,
 		const char *uname, int depth, void *data)
 {
Index: 2.6.24-rc5/include/asm/rtas.h
===================================================================
--- 2.6.24-rc5.orig/include/asm/rtas.h	2008-01-18 07:37:28.000000000 -0600
+++ 2.6.24-rc5/include/asm/rtas.h	2008-01-18 07:37:33.000000000 -0600
@@ -183,6 +183,9 @@ extern unsigned int rtas_busy_delay(int 
 
 extern int early_init_dt_scan_rtas(unsigned long node,
 		const char *uname, int depth, void *data);
+int early_init_dt_scan_phyp_dump(unsigned long node,
+		const char *uname, int depth, void *data);
+
 
 extern void pSeries_log_error(char *buf, unsigned int err_type, int fatal);
 

[PATCH 3/8] pseries: phyp dump: use sysfs to release reserved mem

[Manish Ahuja]

Check to see if there actually is data from a previously
crashed kernel waiting. If so, Allow user-sapce tools to
grab the data (by reading /proc/kcore). When user-space 
finishes dumping a section, it must release that memory
by writing to sysfs. For example,

  echo "0x40000000 0x10000000" > /sys/kernel/release_region

will release 256MB starting at the 1GB.  The released memory
becomes free for general use.

Signed-off-by: Linas Vepstas <linasvepstas@gmail.com>

------
 arch/powerpc/platforms/pseries/phyp_dump.c |  102 +++++++++++++++++++++++++++--
 1 file changed, 96 insertions(+), 6 deletions(-)

Index: 2.6.24-rc5/arch/powerpc/platforms/pseries/phyp_dump.c
===================================================================
--- 2.6.24-rc5.orig/arch/powerpc/platforms/pseries/phyp_dump.c	2008-01-18 07:37:33.000000000 -0600
+++ 2.6.24-rc5/arch/powerpc/platforms/pseries/phyp_dump.c	2008-01-18 22:43:00.000000000 -0600
@@ -12,17 +12,24 @@
  */
 
 #include <linux/init.h>
+#include <linux/kobject.h>
 #include <linux/mm.h>
+#include <linux/of.h>
 #include <linux/pfn.h>
 #include <linux/swap.h>
+#include <linux/sysfs.h>
 
 #include <asm/page.h>
 #include <asm/phyp_dump.h>
+#include <asm/rtas.h>
 
 /* Global, used to communicate data between early boot and late boot */
 static struct phyp_dump phyp_dump_global;
 struct phyp_dump *phyp_dump_info = &phyp_dump_global;
 
+static int ibm_configure_kernel_dump;
+
+/* ------------------------------------------------- */
 /**
  * release_memory_range -- release memory previously lmb_reserved
  * @start_pfn: starting physical frame number
@@ -52,20 +59,103 @@ release_memory_range(unsigned long start
 	}
 }
 
-static int __init phyp_dump_setup(void)
+/* ------------------------------------------------- */
+/**
+ * sysfs_release_region -- sysfs interface to release memory range.
+ *
+ * Usage:
+ *   "echo <start addr> <length> > /sys/kernel/release_region"
+ *
+ * Example:
+ *   "echo 0x40000000 0x10000000 > /sys/kernel/release_region"
+ *
+ * will release 256MB starting at 1GB.
+ */
+static ssize_t
+store_release_region(struct kset *kset, const char *buf, size_t count)
 {
+	unsigned long start_addr, length, end_addr;
 	unsigned long start_pfn, nr_pages;
+	ssize_t ret;
 
-	/* If no memory was reserved in early boot, there is nothing to do */
-	if (phyp_dump_info->init_reserve_size == 0)
-		return 0;
+	ret = sscanf(buf, "%lx %lx", &start_addr, &length);
+	if (ret != 2)
+		return -EINVAL;
+
+	/* Range-check - don't free any reserved memory that
+	 * wasn't reserved for phyp-dump */
+	if (start_addr < phyp_dump_info->init_reserve_start)
+		start_addr = phyp_dump_info->init_reserve_start;
+
+	end_addr = phyp_dump_info->init_reserve_start +
+			phyp_dump_info->init_reserve_size;
+	if (start_addr+length > end_addr)
+		length = end_addr - start_addr;
+
+	/* Release the region of memory assed in by user */
+	start_pfn = PFN_DOWN(start_addr);
+	nr_pages = PFN_DOWN(length);
+	release_memory_range (start_pfn, nr_pages);
 
-	/* Release memory that was reserved in early boot */
+	return count;
+}
+
+static ssize_t
+show_release_region(struct kset * kset, char *buf)
+{
+	return sprintf(buf, "ola\n");
+}
+
+static struct subsys_attribute rr = __ATTR(release_region, 0600,
+					 show_release_region,
+					 store_release_region);
+
+/* ------------------------------------------------- */
+
+static void release_all (void)
+{
+	unsigned long start_pfn, nr_pages;
+
+	/* Release all memory that was reserved in early boot */
 	start_pfn = PFN_DOWN(phyp_dump_info->init_reserve_start);
 	nr_pages = PFN_DOWN(phyp_dump_info->init_reserve_size);
 	release_memory_range(start_pfn, nr_pages);
+}
+
+static int __init phyp_dump_setup(void)
+{
+	struct device_node *rtas;
+	const int *dump_header;
+	int header_len = 0;
+	int rc;
+
+	/* If no memory was reserved in early boot, there is nothing to do */
+	if (phyp_dump_info->init_reserve_size == 0)
+		return 0;
+
+	/* Return if phyp dump not supported */
+	ibm_configure_kernel_dump = rtas_token("ibm,configure-kernel-dump");
+	if (ibm_configure_kernel_dump == RTAS_UNKNOWN_SERVICE) {
+		release_all();
+		return -ENOSYS;
+	}
+
+	/* Is there dump data waiting for us? */
+	rtas = of_find_node_by_path("/rtas");
+	dump_header = of_get_property(rtas, "ibm,kernel-dump", &header_len);
+	if (dump_header == NULL) {
+		release_all();
+		return 0;
+	}
+
+	/* Should we create a dump_subsys, analogous to s390/ipl.c ? */
+	rc = subsys_create_file(&kernel_subsys, &rr);
+	if (rc) {
+		printk (KERN_ERR "phyp-dump: unable to create sysfs file (%d)\n", rc);
+		release_all();
+		return 0;
+	}
 
 	return 0;
 }
-
 subsys_initcall(phyp_dump_setup);

[PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Manish Ahuja]

Initial patch for reserving memory in early boot, and freeing it later.
If the previous boot had ended with a crash, the reserved memory would contain
a copy of the crashed kernel data.

Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
Signed-off-by: Linas Vepstas <linasvepstas@gmail.com>

----
 arch/powerpc/kernel/prom.c                 |   46 ++++++++++++++++++
 arch/powerpc/kernel/rtas.c                 |   27 +++++++++++
 arch/powerpc/platforms/pseries/Makefile    |    1 
 arch/powerpc/platforms/pseries/phyp_dump.c |   71 +++++++++++++++++++++++++++++
 include/asm-powerpc/phyp_dump.h            |   37 +++++++++++++++
 include/asm/rtas.h                         |    3 +
 6 files changed, 185 insertions(+)

Index: 2.6.24-rc5/include/asm-powerpc/phyp_dump.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ 2.6.24-rc5/include/asm-powerpc/phyp_dump.h	2008-01-18 07:37:33.000000000 -0600
@@ -0,0 +1,37 @@
+/*
+ * Hypervisor-assisted dump
+ *
+ * Linas Vepstas, Manish Ahuja 2007
+ * Copyright (c) 2007 IBM Corp.
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _PPC64_PHYP_DUMP_H
+#define _PPC64_PHYP_DUMP_H
+
+#ifdef CONFIG_PHYP_DUMP
+
+/* The RMR region will be saved for later dumping
+ * whenever the kernel crashes. Set this to 256MB. */
+#define PHYP_DUMP_RMR_START 0x0
+#define PHYP_DUMP_RMR_END   (1UL<<28)
+
+struct phyp_dump {
+	/* Memory that is reserved during very early boot. */
+	unsigned long init_reserve_start;
+	unsigned long init_reserve_size;
+	/* Check status during boot if dump active & present*/
+	unsigned long phyp_dump_is_active;
+	/* store cpu & hpte size */
+	unsigned long cpu_state_size;
+	unsigned long hpte_region_size;
+};
+
+extern struct phyp_dump *phyp_dump_info;
+
+#endif /* CONFIG_PHYP_DUMP */
+#endif /* _PPC64_PHYP_DUMP_H */
Index: 2.6.24-rc5/arch/powerpc/platforms/pseries/phyp_dump.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ 2.6.24-rc5/arch/powerpc/platforms/pseries/phyp_dump.c	2008-01-18 07:37:33.000000000 -0600
@@ -0,0 +1,71 @@
+/*
+ * Hypervisor-assisted dump
+ *
+ * Linas Vepstas, Manish Ahuja 2007
+ * Copyrhgit (c) 2007 IBM Corp.
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/pfn.h>
+#include <linux/swap.h>
+
+#include <asm/page.h>
+#include <asm/phyp_dump.h>
+
+/* Global, used to communicate data between early boot and late boot */
+static struct phyp_dump phyp_dump_global;
+struct phyp_dump *phyp_dump_info = &phyp_dump_global;
+
+/**
+ * release_memory_range -- release memory previously lmb_reserved
+ * @start_pfn: starting physical frame number
+ * @nr_pages: number of pages to free.
+ *
+ * This routine will release memory that had been previously
+ * lmb_reserved in early boot. The released memory becomes
+ * available for genreal use.
+ */
+static void
+release_memory_range(unsigned long start_pfn, unsigned long nr_pages)
+{
+	struct page *rpage;
+	unsigned long end_pfn;
+	long i;
+
+	end_pfn = start_pfn + nr_pages;
+
+	for (i=start_pfn; i <= end_pfn; i++) {
+		rpage = pfn_to_page(i);
+		if (PageReserved(rpage)) {
+			ClearPageReserved(rpage);
+			init_page_count(rpage);
+			__free_page(rpage);
+			totalram_pages++;
+		}
+	}
+}
+
+static int __init phyp_dump_setup(void)
+{
+	unsigned long start_pfn, nr_pages;
+
+	/* If no memory was reserved in early boot, there is nothing to do */
+	if (phyp_dump_info->init_reserve_size == 0)
+		return 0;
+
+	/* Release memory that was reserved in early boot */
+	start_pfn = PFN_DOWN(phyp_dump_info->init_reserve_start);
+	nr_pages = PFN_DOWN(phyp_dump_info->init_reserve_size);
+	release_memory_range(start_pfn, nr_pages);
+
+	return 0;
+}
+
+subsys_initcall(phyp_dump_setup);
Index: 2.6.24-rc5/arch/powerpc/platforms/pseries/Makefile
===================================================================
--- 2.6.24-rc5.orig/arch/powerpc/platforms/pseries/Makefile	2008-01-18 07:37:28.000000000 -0600
+++ 2.6.24-rc5/arch/powerpc/platforms/pseries/Makefile	2008-01-18 07:37:33.000000000 -0600
@@ -18,3 +18,4 @@ obj-$(CONFIG_HOTPLUG_CPU)	+= hotplug-cpu
 obj-$(CONFIG_HVC_CONSOLE)	+= hvconsole.o
 obj-$(CONFIG_HVCS)		+= hvcserver.o
 obj-$(CONFIG_HCALL_STATS)	+= hvCall_inst.o
+obj-$(CONFIG_PHYP_DUMP)	+= phyp_dump.o
Index: 2.6.24-rc5/arch/powerpc/kernel/prom.c
===================================================================
--- 2.6.24-rc5.orig/arch/powerpc/kernel/prom.c	2008-01-18 07:37:28.000000000 -0600
+++ 2.6.24-rc5/arch/powerpc/kernel/prom.c	2008-01-18 07:37:33.000000000 -0600
@@ -51,6 +51,7 @@
 #include <asm/machdep.h>
 #include <asm/pSeries_reconfig.h>
 #include <asm/pci-bridge.h>
+#include <asm/phyp_dump.h>
 #include <asm/kexec.h>
 
 #ifdef DEBUG
@@ -1011,6 +1012,48 @@ static void __init early_reserve_mem(voi
 #endif
 }
 
+#ifdef CONFIG_PHYP_DUMP
+
+/**
+ * reserve_crashed_mem() - reserve all not-yet-dumped mmemory
+ *
+ * This routine will reserve almost all of the memory in the
+ * system, except for a few hundred megabytes used to boot the
+ * new kernel. As the reserved memory is dumped to the dump
+ * device (by userland tools), it will be freed and made available.
+ */
+static void __init reserve_crashed_mem(void)
+{
+	unsigned long base, size;
+
+	if (phyp_dump_info->phyp_dump_is_active) {
+		/* Reserve *everything* above RMR. We'll free this real soon.*/
+		base = PHYP_DUMP_RMR_END;
+		size = lmb_end_of_DRAM() - base;
+
+		/* XXX crashed_ram_end is wrong, since it may be beyond
+	 	* the memory_limit, it will need to be adjusted. */
+		lmb_reserve(base, size);
+
+		phyp_dump_info->init_reserve_start = base;
+		phyp_dump_info->init_reserve_size = size;
+	}
+	else {
+		size = phyp_dump_info->cpu_state_size +
+			phyp_dump_info->hpte_region_size +
+			PHYP_DUMP_RMR_END;
+		base = lmb_end_of_DRAM() - size;
+	printk(KERN_ERR "Manish reserve regular kernel space is %ld %ld\n", base, size);
+		lmb_reserve(base, size);
+		phyp_dump_info->init_reserve_start = base;
+		phyp_dump_info->init_reserve_size = size;
+	}
+}
+#else
+static inline void __init reserve_crashed_mem(void) {}
+#endif /* CONFIG_PHYP_DUMP */
+
+
 void __init early_init_devtree(void *params)
 {
 	DBG(" -> early_init_devtree(%p)\n", params);
@@ -1022,6 +1065,8 @@ void __init early_init_devtree(void *par
 	/* Some machines might need RTAS info for debugging, grab it now. */
 	of_scan_flat_dt(early_init_dt_scan_rtas, NULL);
 #endif
+	/* scan tree to see if dump occured during last boot */
+	of_scan_flat_dt(early_init_dt_scan_phyp_dump, NULL);
 
 	/* Retrieve various informations from the /chosen node of the
 	 * device-tree, including the platform type, initrd location and
@@ -1043,6 +1088,7 @@ void __init early_init_devtree(void *par
 	reserve_kdump_trampoline();
 	reserve_crashkernel();
 	early_reserve_mem();
+	reserve_crashed_mem();
 
 	lmb_enforce_memory_limit(memory_limit);
 	lmb_analyze();
Index: 2.6.24-rc5/arch/powerpc/kernel/rtas.c
===================================================================
--- 2.6.24-rc5.orig/arch/powerpc/kernel/rtas.c	2008-01-18 07:37:28.000000000 -0600
+++ 2.6.24-rc5/arch/powerpc/kernel/rtas.c	2008-01-18 07:37:33.000000000 -0600
@@ -39,6 +39,7 @@
 #include <asm/syscalls.h>
 #include <asm/smp.h>
 #include <asm/atomic.h>
+#include <asm/phyp_dump.h>
 
 struct rtas_t rtas = {
 	.lock = SPIN_LOCK_UNLOCKED
@@ -883,6 +884,32 @@ void __init rtas_initialize(void)
 #endif
 }
 
+int __init early_init_dt_scan_phyp_dump(unsigned long node,
+		const char *uname, int depth, void *data)
+{
+#ifdef CONFIG_PHYP_DUMP
+	const unsigned int *sizes;
+
+	phyp_dump_info->phyp_dump_is_active = 0;
+	if (depth != 1 || strcmp(uname, "rtas") != 0)
+		return 0;
+
+	if (of_get_flat_dt_prop(node, "ibm,dump-kernel", NULL))
+		phyp_dump_info->phyp_dump_is_active++;
+
+	sizes = of_get_flat_dt_prop(node, "ibm,configure-kernel-dump-sizes", NULL);
+	if (!sizes)
+		return 0;
+
+	if (sizes[0] == 1)
+		phyp_dump_info->cpu_state_size = *((unsigned long *)&sizes[1]);
+
+	if (sizes[3] == 2)
+		phyp_dump_info->hpte_region_size = *((unsigned long *)&sizes[4]);
+#endif
+	return 1;
+}
+
 int __init early_init_dt_scan_rtas(unsigned long node,
 		const char *uname, int depth, void *data)
 {
Index: 2.6.24-rc5/include/asm/rtas.h
===================================================================
--- 2.6.24-rc5.orig/include/asm/rtas.h	2008-01-18 07:37:28.000000000 -0600
+++ 2.6.24-rc5/include/asm/rtas.h	2008-01-18 07:37:33.000000000 -0600
@@ -183,6 +183,9 @@ extern unsigned int rtas_busy_delay(int 
 
 extern int early_init_dt_scan_rtas(unsigned long node,
 		const char *uname, int depth, void *data);
+int early_init_dt_scan_phyp_dump(unsigned long node,
+		const char *uname, int depth, void *data);
+
 
 extern void pSeries_log_error(char *buf, unsigned int err_type, int fatal);
 

[PATCH 4/8] pseries: phyp dump: register dump area.

[Manish Ahuja]

Set up the actual dump header, register it with the hypervisor.

Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
Signed-off-by: Linas Vepstas <linasvepstas@gmail.com>

------
 arch/powerpc/platforms/pseries/phyp_dump.c |  136 +++++++++++++++++++++++++++--
 1 file changed, 129 insertions(+), 7 deletions(-)

Index: 2.6.24-rc5/arch/powerpc/platforms/pseries/phyp_dump.c
===================================================================
--- 2.6.24-rc5.orig/arch/powerpc/platforms/pseries/phyp_dump.c	2008-01-18 22:43:00.000000000 -0600
+++ 2.6.24-rc5/arch/powerpc/platforms/pseries/phyp_dump.c	2008-01-21 23:49:23.000000000 -0600
@@ -30,6 +30,117 @@ struct phyp_dump *phyp_dump_info = &phyp
 static int ibm_configure_kernel_dump;
 
 /* ------------------------------------------------- */
+/* RTAS interfaces to declare the dump regions */
+
+struct dump_section {
+	u32 dump_flags;
+	u16 source_type;
+	u16 error_flags;
+	u64 source_address;
+	u64 source_length;
+	u64 length_copied;
+	u64 destination_address;
+};
+
+struct phyp_dump_header {
+	u32 version;
+	u16 num_of_sections;
+	u16 status;
+
+	u32 first_offset_section;
+	u32 dump_disk_section;
+	u64 block_num_dd;
+	u64 num_of_blocks_dd;
+	u32 offset_dd;
+	u32 maxtime_to_auto;
+	/* No dump disk path string used */
+
+	struct dump_section cpu_data;
+	struct dump_section hpte_data;
+	struct dump_section kernel_data;
+};
+
+/* The dump header *must be* in low memory, so .bss it */
+static struct phyp_dump_header phdr;
+
+#define NUM_DUMP_SECTIONS 3
+#define DUMP_HEADER_VERSION 0x1
+#define DUMP_REQUEST_FLAG 0x1
+#define DUMP_SOURCE_CPU 0x0001
+#define DUMP_SOURCE_HPTE 0x0002
+#define DUMP_SOURCE_RMO  0x0011
+
+/**
+ * init_dump_header() - initialize the header declaring a dump
+ * Returns: length of dump save area.
+ *
+ * When the hypervisor saves crashed state, it needs to put
+ * it somewhere. The dump header tells the hypervisor where
+ * the data can be saved.
+ */
+static unsigned long init_dump_header(struct phyp_dump_header *ph)
+{
+	unsigned long addr_offset = 0;
+
+	/* Set up the dump header */
+	ph->version = DUMP_HEADER_VERSION;
+	ph->num_of_sections = NUM_DUMP_SECTIONS;
+	ph->status = 0;
+
+	ph->first_offset_section =
+		(u32)offsetof(struct phyp_dump_header, cpu_data);
+	ph->dump_disk_section = 0;
+	ph->block_num_dd = 0;
+	ph->num_of_blocks_dd = 0;
+	ph->offset_dd = 0;
+
+	ph->maxtime_to_auto = 0; /* disabled */
+
+	/* The first two sections are mandatory */
+	ph->cpu_data.dump_flags = DUMP_REQUEST_FLAG;
+	ph->cpu_data.source_type = DUMP_SOURCE_CPU;
+	ph->cpu_data.source_address = 0;
+	ph->cpu_data.source_length = phyp_dump_info->cpu_state_size;
+	ph->cpu_data.destination_address = addr_offset;
+	addr_offset += phyp_dump_info->cpu_state_size;
+
+	ph->hpte_data.dump_flags = DUMP_REQUEST_FLAG;
+	ph->hpte_data.source_type = DUMP_SOURCE_HPTE;
+	ph->hpte_data.source_address = 0;
+	ph->hpte_data.source_length = phyp_dump_info->hpte_region_size;
+	ph->hpte_data.destination_address = addr_offset;
+	addr_offset += phyp_dump_info->hpte_region_size;
+
+	/* This section describes the low kernel region */
+	ph->kernel_data.dump_flags = DUMP_REQUEST_FLAG;
+	ph->kernel_data.source_type = DUMP_SOURCE_RMO;
+	ph->kernel_data.source_address = PHYP_DUMP_RMR_START;
+	ph->kernel_data.source_length = PHYP_DUMP_RMR_END;
+	ph->kernel_data.destination_address = addr_offset;
+	addr_offset += ph->kernel_data.source_length;
+
+	return addr_offset;
+}
+
+static void register_dump_area(struct phyp_dump_header *ph, unsigned long addr)
+{
+	int rc;
+	ph->cpu_data.destination_address += addr;
+	ph->hpte_data.destination_address += addr;
+	ph->kernel_data.destination_address += addr;
+
+	do {
+		rc = rtas_call(ibm_configure_kernel_dump, 3, 1, NULL,
+		               1, ph, sizeof(struct phyp_dump_header));
+	} while (rtas_busy_delay(rc));
+
+	if (rc)
+	{
+		printk (KERN_ERR "phyp-dump: unexpected error (%d) on register\n", rc);
+	}
+}
+
+/* ------------------------------------------------- */
 /**
  * release_memory_range -- release memory previously lmb_reserved
  * @start_pfn: starting physical frame number
@@ -125,7 +236,9 @@ static void release_all (void)
 static int __init phyp_dump_setup(void)
 {
 	struct device_node *rtas;
-	const int *dump_header;
+	const struct phyp_dump_header *dump_header;
+	unsigned long dump_area_start;
+	unsigned long dump_area_length;
 	int header_len = 0;
 	int rc;
 
@@ -140,22 +253,31 @@ static int __init phyp_dump_setup(void)
 		return -ENOSYS;
 	}
 
-	/* Is there dump data waiting for us? */
+	/* Is there dump data waiting for us? If there isn't,
+	 * then register a new dump area, and release all of
+	 * the rest of the reserved ram.
+	 *
+	 * The /rtas/ibm,kernel-dump rtas node is present only
+	 * if there is dump data waiting for us.
+	 */
 	rtas = of_find_node_by_path("/rtas");
 	dump_header = of_get_property(rtas, "ibm,kernel-dump", &header_len);
+	of_node_put(rtas);
+
+	dump_area_length = init_dump_header(&phdr);
+	dump_area_start = phyp_dump_info->init_reserve_start & PAGE_MASK; /* align down */
+
 	if (dump_header == NULL) {
-		release_all();
+		register_dump_area(&phdr, dump_area_start);
 		return 0;
 	}
 
 	/* Should we create a dump_subsys, analogous to s390/ipl.c ? */
 	rc = subsys_create_file(&kernel_subsys, &rr);
-	if (rc) {
+	if (rc)
 		printk (KERN_ERR "phyp-dump: unable to create sysfs file (%d)\n", rc);
-		release_all();
-		return 0;
-	}
 
+	/* ToDo: re-register the dump area, for next time. */
 	return 0;
 }
 subsys_initcall(phyp_dump_setup);

Re: [PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Manish Ahuja]

Reposted this one. I got the email id wrong in this one.

Sorry about that. 

Manish

[PATCH 5/8] pseries: phyp dump: debugging print routines.

[Manish Ahuja]

Provide some basic debugging support.

Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
Signed-off-by: Linas Vepstas <linasvepstas@gmail.com>
-----

 arch/powerpc/platforms/pseries/phyp_dump.c |   64 +++++++++++++++++++++++++++--
 1 file changed, 60 insertions(+), 4 deletions(-)

Index: 2.6.24-rc5/arch/powerpc/platforms/pseries/phyp_dump.c
===================================================================
--- 2.6.24-rc5.orig/arch/powerpc/platforms/pseries/phyp_dump.c	2008-01-21 02:51:54.000000000 -0600
+++ 2.6.24-rc5/arch/powerpc/platforms/pseries/phyp_dump.c	2008-01-21 02:58:41.000000000 -0600
@@ -2,7 +2,7 @@
  * Hypervisor-assisted dump
  *
  * Linas Vepstas, Manish Ahuja 2007
- * Copyrhgit (c) 2007 IBM Corp.
+ * Copyright (c) 2007 IBM Corp.
  *
  *      This program is free software; you can redistribute it and/or
  *      modify it under the terms of the GNU General Public License
@@ -122,6 +122,61 @@ static unsigned long init_dump_header(st
 	return addr_offset;
 }
 
+static void print_dump_header(const struct phyp_dump_header *ph)
+{
+#ifdef DEBUG
+	printk(KERN_INFO "dump header:\n");
+	/* setup some ph->sections required */
+	printk(KERN_INFO "version = %d\n", ph->version);
+	printk(KERN_INFO "Sections = %d\n", ph->num_of_sections);
+	printk(KERN_INFO "Status = 0x%x\n", ph->status);
+
+	/* No ph->disk, so all should be set to 0 */
+	printk(KERN_INFO "Offset to first section 0x%x\n",
+						ph->first_offset_section);
+	printk(KERN_INFO "dump disk sections should be zero\n");
+	printk(KERN_INFO "dump disk section = %d\n", ph->dump_disk_section);
+	printk(KERN_INFO "block num = %ld\n", ph->block_num_dd);
+	printk(KERN_INFO "number of blocks = %ld\n", ph->num_of_blocks_dd);
+	printk(KERN_INFO "dump disk offset = %d\n", ph->offset_dd);
+	printk(KERN_INFO "Max auto time= %d\n", ph->maxtime_to_auto);
+
+	/*set cpu state and hpte states as well scratch pad area */
+	printk(KERN_INFO " CPU AREA \n");
+	printk(KERN_INFO "cpu dump_flags =%d\n", ph->cpu_data.dump_flags);
+	printk(KERN_INFO "cpu source_type =%d\n", ph->cpu_data.source_type);
+	printk(KERN_INFO "cpu error_flags =%d\n", ph->cpu_data.error_flags);
+	printk(KERN_INFO "cpu source_address =%lx\n",
+						ph->cpu_data.source_address);
+	printk(KERN_INFO "cpu source_length =%lx\n",
+						ph->cpu_data.source_length);
+	printk(KERN_INFO "cpu length_copied =%lx\n",
+						ph->cpu_data.length_copied);
+
+	printk(KERN_INFO " HPTE AREA \n");
+	printk(KERN_INFO "HPTE dump_flags =%d\n", ph->hpte_data.dump_flags);
+	printk(KERN_INFO "HPTE source_type =%d\n", ph->hpte_data.source_type);
+	printk(KERN_INFO "HPTE error_flags =%d\n", ph->hpte_data.error_flags);
+	printk(KERN_INFO "HPTE source_address =%lx\n",
+						ph->hpte_data.source_address);
+	printk(KERN_INFO "HPTE source_length =%lx\n",
+						ph->hpte_data.source_length);
+	printk(KERN_INFO "HPTE length_copied =%lx\n",
+						ph->hpte_data.length_copied);
+
+	printk(KERN_INFO " SRSD AREA \n");
+	printk(KERN_INFO "SRSD dump_flags =%d\n", ph->kernel_data.dump_flags);
+	printk(KERN_INFO "SRSD source_type =%d\n", ph->kernel_data.source_type);
+	printk(KERN_INFO "SRSD error_flags =%d\n", ph->kernel_data.error_flags);
+	printk(KERN_INFO "SRSD source_address =%lx\n",
+						ph->kernel_data.source_address);
+	printk(KERN_INFO "SRSD source_length =%lx\n",
+						ph->kernel_data.source_length);
+	printk(KERN_INFO "SRSD length_copied =%lx\n",
+						ph->kernel_data.length_copied);
+#endif
+}
+
 static void register_dump_area(struct phyp_dump_header *ph, unsigned long addr)
 {
 	int rc;
@@ -134,9 +189,9 @@ static void register_dump_area(struct ph
 		               1, ph, sizeof(struct phyp_dump_header));
 	} while (rtas_busy_delay(rc));
 
-	if (rc)
-	{
-		printk (KERN_ERR "phyp-dump: unexpected error (%d) on register\n", rc);
+	if (rc) {
+		printk(KERN_ERR "phyp-dump: unexpected error (%d) on register\n", rc);
+		print_dump_header(ph);
 	}
 }
 
@@ -249,6 +304,7 @@ static int __init phyp_dump_setup(void)
 		release_all();
 		return -ENOSYS;
 	}
+	print_dump_header(dump_header);
 
 	/* Is there dump data waiting for us? If there isn't,
 	 * then register a new dump area, and release all of

[PATCH 6/8] pseries: phyp dump: Unregister and print dump areas.

[Manish Ahuja]

Routines to invalidate and unregister dump routines. 
Unregister has not been used yet, I will release another
patch for that at a later stage with the kdump integration patches.

There is also a routine which calculates the regions to be
freed and exports that through sysfs.

Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
-----

---
 arch/powerpc/platforms/pseries/phyp_dump.c |  101 +++++++++++++++++++++++++----
 include/asm/phyp_dump.h                    |    3 
 2 files changed, 93 insertions(+), 11 deletions(-)

Index: 2.6.24-rc5/arch/powerpc/platforms/pseries/phyp_dump.c
===================================================================
--- 2.6.24-rc5.orig/arch/powerpc/platforms/pseries/phyp_dump.c	2008-01-21 23:06:20.000000000 -0600
+++ 2.6.24-rc5/arch/powerpc/platforms/pseries/phyp_dump.c	2008-01-21 23:49:10.000000000 -0600
@@ -69,6 +69,10 @@ static struct phyp_dump_header phdr;
 #define DUMP_SOURCE_CPU 0x0001
 #define DUMP_SOURCE_HPTE 0x0002
 #define DUMP_SOURCE_RMO  0x0011
+#define DUMP_ERROR_FLAG 0x2000
+#define DUMP_TRIGGERED 0x4000
+#define DUMP_PERFORMED 0x8000
+
 
 /**
  * init_dump_header() - initialize the header declaring a dump
@@ -180,9 +184,15 @@ static void print_dump_header(const stru
 static void register_dump_area(struct phyp_dump_header *ph, unsigned long addr)
 {
 	int rc;
-	ph->cpu_data.destination_address += addr;
-	ph->hpte_data.destination_address += addr;
-	ph->kernel_data.destination_address += addr;
+
+	/* Add addr value if not initialized before */
+	if (ph->cpu_data.destination_address == 0) {
+		ph->cpu_data.destination_address += addr;
+		ph->hpte_data.destination_address += addr;
+		ph->kernel_data.destination_address += addr;
+	}
+
+	/* ToDo Invalidate kdump and free memory range. */
 
 	do {
 		rc = rtas_call(ibm_configure_kernel_dump, 3, 1, NULL,
@@ -195,6 +205,46 @@ static void register_dump_area(struct ph
 	}
 }
 
+static
+void invalidate_last_dump(struct phyp_dump_header *ph, unsigned long addr)
+{
+	int rc;
+
+	/* Add addr value if not initialized before */
+	if (ph->cpu_data.destination_address == 0) {
+		ph->cpu_data.destination_address += addr;
+		ph->hpte_data.destination_address += addr;
+		ph->kernel_data.destination_address += addr;
+	}
+
+	do {
+		rc = rtas_call(ibm_configure_kernel_dump, 3, 1, NULL,
+		               2, ph, sizeof(struct phyp_dump_header));
+	} while (rtas_busy_delay(rc));
+
+	if (rc) {
+		printk (KERN_ERR "phyp-dump: unexpected error (%d) "
+						"on invalidate\n", rc);
+		print_dump_header(ph);
+	}
+}
+
+static void unregister_dump_area(struct phyp_dump_header *ph)
+{
+	int rc;
+
+	do {
+		rc = rtas_call(ibm_configure_kernel_dump, 3, 1, NULL,
+		               3, ph, sizeof(struct phyp_dump_header));
+	} while (rtas_busy_delay(rc));
+
+	if (rc) {
+		printk (KERN_ERR "phyp-dump: unexpected error (%d) "
+						"on unregister\n", rc);
+		print_dump_header(ph);
+	}
+}
+
 /* ------------------------------------------------- */
 /**
  * release_memory_range -- release memory previously lmb_reserved
@@ -205,8 +255,8 @@ static void register_dump_area(struct ph
  * lmb_reserved in early boot. The released memory becomes
  * available for genreal use.
  */
-static void
-release_memory_range(unsigned long start_pfn, unsigned long nr_pages)
+static
+void release_memory_range(unsigned long start_pfn, unsigned long nr_pages)
 {
 	struct page *rpage;
 	unsigned long end_pfn;
@@ -237,8 +287,8 @@ release_memory_range(unsigned long start
  *
  * will release 256MB starting at 1GB.
  */
-static ssize_t
-store_release_region(struct kset *kset, const char *buf, size_t count)
+static
+ssize_t store_release_region(struct kset *kset, const char *buf, size_t count)
 {
 	unsigned long start_addr, length, end_addr;
 	unsigned long start_pfn, nr_pages;
@@ -266,10 +316,23 @@ store_release_region(struct kset *kset, 
 	return count;
 }
 
-static ssize_t
-show_release_region(struct kset * kset, char *buf)
+static ssize_t show_release_region(struct kset * kset, char *buf)
 {
-	return sprintf(buf, "ola\n");
+	u64 second_addr_range;
+
+	/* total reserved size - start of scratch area */
+	second_addr_range = phyp_dump_info->init_reserve_size -
+				phyp_dump_info->reserved_scratch_size;
+	return sprintf(buf, "CPU:0x%lx-0x%lx: HPTE:0x%lx-0x%lx:"
+			    " DUMP:0x%lx-0x%lx, 0x%lx-0x%lx:\n",
+		phdr.cpu_data.destination_address,
+		phdr.cpu_data.length_copied,
+		phdr.hpte_data.destination_address,
+		phdr.hpte_data.length_copied,
+		phdr.kernel_data.destination_address,
+		phdr.kernel_data.length_copied,
+		phyp_dump_info->init_reserve_start,
+		second_addr_range);
 }
 
 static struct subsys_attribute rr = __ATTR(release_region, 0600,
@@ -307,7 +370,6 @@ static int __init phyp_dump_setup(void)
 		release_all();
 		return -ENOSYS;
 	}
-	print_dump_header(dump_header);
 
 	/* Is there dump data waiting for us? If there isn't,
 	 * then register a new dump area, and release all of
@@ -319,6 +381,7 @@ static int __init phyp_dump_setup(void)
 	rtas = of_find_node_by_path("/rtas");
 	dump_header = of_get_property(rtas, "ibm,kernel-dump", &header_len);
 	of_node_put(rtas);
+	print_dump_header(dump_header);
 
 	dump_area_length = init_dump_header(&phdr);
 	dump_area_start = phyp_dump_info->init_reserve_start & PAGE_MASK; /* align down */
@@ -328,6 +391,22 @@ static int __init phyp_dump_setup(void)
 		return 0;
 	}
 
+	/* re-register the dump area, if old dump was invalid */
+	if ((dump_header) && (dump_header->status & DUMP_ERROR_FLAG)) {
+		invalidate_last_dump(&phdr, dump_area_start);
+		register_dump_area(&phdr, dump_area_start);
+		return 0;
+	}
+
+	if (dump_header) {
+		phyp_dump_info->reserved_scratch_addr =
+				dump_header->cpu_data.destination_address;
+		phyp_dump_info->reserved_scratch_size =
+				dump_header->cpu_data.source_length +
+				dump_header->hpte_data.source_length +
+				dump_header->kernel_data.source_length;
+	}
+
 	/* Should we create a dump_subsys, analogous to s390/ipl.c ? */
 	rc = subsys_create_file(&kernel_subsys, &rr);
 	if (rc)
Index: 2.6.24-rc5/include/asm/phyp_dump.h
===================================================================
--- 2.6.24-rc5.orig/include/asm/phyp_dump.h	2008-01-21 22:21:01.000000000 -0600
+++ 2.6.24-rc5/include/asm/phyp_dump.h	2008-01-21 23:29:05.000000000 -0600
@@ -29,6 +29,9 @@ struct phyp_dump {
 	/* store cpu & hpte size */
 	unsigned long cpu_state_size;
 	unsigned long hpte_region_size;
+	/* previous scratch area values */
+	unsigned long reserved_scratch_addr;
+	unsigned long reserved_scratch_size;
 };
 
 extern struct phyp_dump *phyp_dump_info;

[PATCH 7/8] pseries: phyp dump: Tracking memory range freed.

[Manish Ahuja]

This patch tracks the size freed. For now it does a simple
rudimentary calculation of the ranges freed. The idea is
to keep it simple at the external shell script level and 
send in large chunks for now.

Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
-----

---
 arch/powerpc/platforms/pseries/phyp_dump.c |   35 +++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

Index: 2.6.24-rc5/arch/powerpc/platforms/pseries/phyp_dump.c
===================================================================
--- 2.6.24-rc5.orig/arch/powerpc/platforms/pseries/phyp_dump.c	2008-01-21 23:30:18.000000000 -0600
+++ 2.6.24-rc5/arch/powerpc/platforms/pseries/phyp_dump.c	2008-01-21 23:42:04.000000000 -0600
@@ -275,6 +275,39 @@ void release_memory_range(unsigned long 
 	}
 }
 
+/**
+ * track_freed_range -- Counts the range being freed.
+ * Once the counter goes to zero, it re-registers dump for
+ * future use.
+ */
+static void
+track_freed_range(unsigned long addr, unsigned long length)
+{
+	static unsigned long scratch_area_size, reserved_area_size;
+
+	if (addr < phyp_dump_info->init_reserve_start)
+		return;
+
+	if ((addr >= phyp_dump_info->init_reserve_start) &&
+	    (addr <= phyp_dump_info->init_reserve_start +
+	     phyp_dump_info->init_reserve_size))
+		reserved_area_size += length;
+
+	if ((addr >= phyp_dump_info->reserved_scratch_addr) &&
+	    (addr <= phyp_dump_info->reserved_scratch_addr +
+	     phyp_dump_info->reserved_scratch_size))
+		scratch_area_size += length;
+
+	if ((reserved_area_size == phyp_dump_info->init_reserve_size) &&
+	    (scratch_area_size == phyp_dump_info->reserved_scratch_size)) {
+
+		invalidate_last_dump(&phdr,
+				phyp_dump_info->reserved_scratch_addr);
+		register_dump_area (&phdr,
+				phyp_dump_info->reserved_scratch_addr);
+	}
+}
+
 /* ------------------------------------------------- */
 /**
  * sysfs_release_region -- sysfs interface to release memory range.
@@ -298,6 +331,8 @@ ssize_t store_release_region(struct kset
 	if (ret != 2)
 		return -EINVAL;
 
+	track_freed_range(start_addr, length);
+
 	/* Range-check - don't free any reserved memory that
 	 * wasn't reserved for phyp-dump */
 	if (start_addr < phyp_dump_info->init_reserve_start)

[PATCH 8/8] pseries: phyp dump: config file

[Manish Ahuja]

To: linuxppc-dev@ozlabs.org


Add hypervisor-assisted dump to kernel config

Signed-off-by: Linas Vepstas <linasvepstas@gmail.com>

-----
 arch/powerpc/Kconfig |   11 +++++++++++
 1 file changed, 11 insertions(+)

Index: linux-2.6.24-rc2-git4/arch/powerpc/Kconfig
===================================================================
--- linux-2.6.24-rc2-git4.orig/arch/powerpc/Kconfig	2007-11-14 16:39:20.000000000 -0600
+++ linux-2.6.24-rc2-git4/arch/powerpc/Kconfig	2007-11-15 14:27:33.000000000 -0600
@@ -261,6 +261,17 @@ config CRASH_DUMP
 
 	  Don't change this unless you know what you are doing.
 
+config PHYP_DUMP
+	bool "Hypervisor-assisted dump (EXPERIMENTAL)"
+	depends on PPC_PSERIES && EXPERIMENTAL
+	default y
+	help
+	  Hypervisor-assisted dump is meant to be a kdump replacement
+	  offering robustness and speed not possible without system
+	  hypervisor assistence.
+
+	  If unsure, say "Y"
+
 config PPCBUG_NVRAM
 	bool "Enable reading PPCBUG NVRAM during boot" if PPLUS || LOPEC
 	default y if PPC_PREP

Re: [PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Paul Mackerras]

Manish Ahuja writes:

> Initial patch for reserving memory in early boot, and freeing it later.
> If the previous boot had ended with a crash, the reserved memory would contain
> a copy of the crashed kernel data.

[snip]

> +static void __init reserve_crashed_mem(void)
> +{
> +	unsigned long base, size;
> +
> +	if (phyp_dump_info->phyp_dump_is_active) {
> +		/* Reserve *everything* above RMR. We'll free this real soon.*/
> +		base = PHYP_DUMP_RMR_END;
> +		size = lmb_end_of_DRAM() - base;
> +
> +		/* XXX crashed_ram_end is wrong, since it may be beyond
> +	 	* the memory_limit, it will need to be adjusted. */
> +		lmb_reserve(base, size);
> +
> +		phyp_dump_info->init_reserve_start = base;
> +		phyp_dump_info->init_reserve_size = size;
> +	}
> +	else {
> +		size = phyp_dump_info->cpu_state_size +
> +			phyp_dump_info->hpte_region_size +
> +			PHYP_DUMP_RMR_END;
> +		base = lmb_end_of_DRAM() - size;
> +	printk(KERN_ERR "Manish reserve regular kernel space is %ld %ld\n", base, size);
> +		lmb_reserve(base, size);

This is still reserving memory even on systems that aren't running on
pHyp at all.  Please rework this so that no memory is reserved if the
system doesn't support phyp-assisted dump.

Paul.

Re: [PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Manish Ahuja]

Sorry,

I think i sent the wrong patch file, it shouldn't have my printk statement in there. Let me re-send 
the correct file and let me test it once more to make sure it does the right thing.

-Manish



Paul Mackerras wrote:
> Manish Ahuja writes:
> 
>> Initial patch for reserving memory in early boot, and freeing it later.
>> If the previous boot had ended with a crash, the reserved memory would contain
>> a copy of the crashed kernel data.
> 
> [snip]
> 
>> +static void __init reserve_crashed_mem(void)
>> +{
>> +	unsigned long base, size;
>> +
>> +	if (phyp_dump_info->phyp_dump_is_active) {
>> +		/* Reserve *everything* above RMR. We'll free this real soon.*/
>> +		base = PHYP_DUMP_RMR_END;
>> +		size = lmb_end_of_DRAM() - base;
>> +
>> +		/* XXX crashed_ram_end is wrong, since it may be beyond
>> +	 	* the memory_limit, it will need to be adjusted. */
>> +		lmb_reserve(base, size);
>> +
>> +		phyp_dump_info->init_reserve_start = base;
>> +		phyp_dump_info->init_reserve_size = size;
>> +	}
>> +	else {
>> +		size = phyp_dump_info->cpu_state_size +
>> +			phyp_dump_info->hpte_region_size +
>> +			PHYP_DUMP_RMR_END;
>> +		base = lmb_end_of_DRAM() - size;
>> +	printk(KERN_ERR "Manish reserve regular kernel space is %ld %ld\n", base, size);
>> +		lmb_reserve(base, size);
> 
> This is still reserving memory even on systems that aren't running on
> pHyp at all.  Please rework this so that no memory is reserved if the
> system doesn't support phyp-assisted dump.
> 
> Paul.

[PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Manish Ahuja]

Initial patch for reserving memory in early boot, and freeing it later.
If the previous boot had ended with a crash, the reserved memory would contain
a copy of the crashed kernel data.

Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
Signed-off-by: Linas Vepstas <linas@austin.ibm.com>

----
 arch/powerpc/kernel/prom.c                 |   50 ++++++++++++++++++++
 arch/powerpc/kernel/rtas.c                 |   32 +++++++++++++
 arch/powerpc/platforms/pseries/Makefile    |    1 
 arch/powerpc/platforms/pseries/phyp_dump.c |   71 +++++++++++++++++++++++++++++
 include/asm-powerpc/phyp_dump.h            |   38 +++++++++++++++
 include/asm/rtas.h                         |    3 +
 6 files changed, 195 insertions(+)

Index: 2.6.24-rc5/include/asm-powerpc/phyp_dump.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ 2.6.24-rc5/include/asm-powerpc/phyp_dump.h	2008-02-12 06:12:37.000000000 -0600
@@ -0,0 +1,38 @@
+/*
+ * Hypervisor-assisted dump
+ *
+ * Linas Vepstas, Manish Ahuja 2007
+ * Copyright (c) 2007 IBM Corp.
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _PPC64_PHYP_DUMP_H
+#define _PPC64_PHYP_DUMP_H
+
+#ifdef CONFIG_PHYP_DUMP
+
+/* The RMR region will be saved for later dumping
+ * whenever the kernel crashes. Set this to 256MB. */
+#define PHYP_DUMP_RMR_START 0x0
+#define PHYP_DUMP_RMR_END   (1UL<<28)
+
+struct phyp_dump {
+	/* Memory that is reserved during very early boot. */
+	unsigned long init_reserve_start;
+	unsigned long init_reserve_size;
+	/* Check status during boot if dump supported, active & present*/
+	unsigned long phyp_dump_configured;
+	unsigned long phyp_dump_is_active;
+	/* store cpu & hpte size */
+	unsigned long cpu_state_size;
+	unsigned long hpte_region_size;
+};
+
+extern struct phyp_dump *phyp_dump_info;
+
+#endif /* CONFIG_PHYP_DUMP */
+#endif /* _PPC64_PHYP_DUMP_H */
Index: 2.6.24-rc5/arch/powerpc/platforms/pseries/phyp_dump.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ 2.6.24-rc5/arch/powerpc/platforms/pseries/phyp_dump.c	2008-02-12 06:12:37.000000000 -0600
@@ -0,0 +1,71 @@
+/*
+ * Hypervisor-assisted dump
+ *
+ * Linas Vepstas, Manish Ahuja 2007
+ * Copyrhgit (c) 2007 IBM Corp.
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/pfn.h>
+#include <linux/swap.h>
+
+#include <asm/page.h>
+#include <asm/phyp_dump.h>
+
+/* Global, used to communicate data between early boot and late boot */
+static struct phyp_dump phyp_dump_global;
+struct phyp_dump *phyp_dump_info = &phyp_dump_global;
+
+/**
+ * release_memory_range -- release memory previously lmb_reserved
+ * @start_pfn: starting physical frame number
+ * @nr_pages: number of pages to free.
+ *
+ * This routine will release memory that had been previously
+ * lmb_reserved in early boot. The released memory becomes
+ * available for genreal use.
+ */
+static void
+release_memory_range(unsigned long start_pfn, unsigned long nr_pages)
+{
+	struct page *rpage;
+	unsigned long end_pfn;
+	long i;
+
+	end_pfn = start_pfn + nr_pages;
+
+	for (i=start_pfn; i <= end_pfn; i++) {
+		rpage = pfn_to_page(i);
+		if (PageReserved(rpage)) {
+			ClearPageReserved(rpage);
+			init_page_count(rpage);
+			__free_page(rpage);
+			totalram_pages++;
+		}
+	}
+}
+
+static int __init phyp_dump_setup(void)
+{
+	unsigned long start_pfn, nr_pages;
+
+	/* If no memory was reserved in early boot, there is nothing to do */
+	if (phyp_dump_info->init_reserve_size == 0)
+		return 0;
+
+	/* Release memory that was reserved in early boot */
+	start_pfn = PFN_DOWN(phyp_dump_info->init_reserve_start);
+	nr_pages = PFN_DOWN(phyp_dump_info->init_reserve_size);
+	release_memory_range(start_pfn, nr_pages);
+
+	return 0;
+}
+
+subsys_initcall(phyp_dump_setup);
Index: 2.6.24-rc5/arch/powerpc/platforms/pseries/Makefile
===================================================================
--- 2.6.24-rc5.orig/arch/powerpc/platforms/pseries/Makefile	2008-02-12 06:12:10.000000000 -0600
+++ 2.6.24-rc5/arch/powerpc/platforms/pseries/Makefile	2008-02-12 06:12:37.000000000 -0600
@@ -18,3 +18,4 @@ obj-$(CONFIG_HOTPLUG_CPU)	+= hotplug-cpu
 obj-$(CONFIG_HVC_CONSOLE)	+= hvconsole.o
 obj-$(CONFIG_HVCS)		+= hvcserver.o
 obj-$(CONFIG_HCALL_STATS)	+= hvCall_inst.o
+obj-$(CONFIG_PHYP_DUMP)	+= phyp_dump.o
Index: 2.6.24-rc5/arch/powerpc/kernel/prom.c
===================================================================
--- 2.6.24-rc5.orig/arch/powerpc/kernel/prom.c	2008-02-12 06:12:10.000000000 -0600
+++ 2.6.24-rc5/arch/powerpc/kernel/prom.c	2008-02-12 06:12:37.000000000 -0600
@@ -51,6 +51,7 @@
 #include <asm/machdep.h>
 #include <asm/pSeries_reconfig.h>
 #include <asm/pci-bridge.h>
+#include <asm/phyp_dump.h>
 #include <asm/kexec.h>
 
 #ifdef DEBUG
@@ -1011,6 +1012,52 @@ static void __init early_reserve_mem(voi
 #endif
 }
 
+#ifdef CONFIG_PHYP_DUMP
+/**
+ * reserve_crashed_mem() - reserve all not-yet-dumped mmemory
+ *
+ * This routine may reserve memory regions in the kernel only
+ * if the system is supported and a dump was taken in last
+ * boot instance or if the hardware is supported and the
+ * scratch area needs to be setup. In other instances it returns
+ * without reserving anything. The memory in case of dump being
+ * active is freed when the dump is collected (by userland tools).
+ */
+static void __init reserve_crashed_mem(void)
+{
+	unsigned long base, size;
+	if (!phyp_dump_info->phyp_dump_configured) {
+		printk(KERN_ERR "Phyp-dump not supported on this hardware\n");
+		return;
+	}
+
+	if (phyp_dump_info->phyp_dump_is_active) {
+		/* Reserve *everything* above RMR.Area freed by userland tools*/
+		base = PHYP_DUMP_RMR_END;
+		size = lmb_end_of_DRAM() - base;
+
+		/* XXX crashed_ram_end is wrong, since it may be beyond
+	 	* the memory_limit, it will need to be adjusted. */
+		lmb_reserve(base, size);
+
+		phyp_dump_info->init_reserve_start = base;
+		phyp_dump_info->init_reserve_size = size;
+	}
+	else {
+		size = phyp_dump_info->cpu_state_size +
+			phyp_dump_info->hpte_region_size +
+			PHYP_DUMP_RMR_END;
+		base = lmb_end_of_DRAM() - size;
+		lmb_reserve(base, size);
+		phyp_dump_info->init_reserve_start = base;
+		phyp_dump_info->init_reserve_size = size;
+	}
+}
+#else
+static inline void __init reserve_crashed_mem(void) {}
+#endif /* CONFIG_PHYP_DUMP */
+
+
 void __init early_init_devtree(void *params)
 {
 	DBG(" -> early_init_devtree(%p)\n", params);
@@ -1022,6 +1069,8 @@ void __init early_init_devtree(void *par
 	/* Some machines might need RTAS info for debugging, grab it now. */
 	of_scan_flat_dt(early_init_dt_scan_rtas, NULL);
 #endif
+	/* scan tree to see if dump occured during last boot */
+	of_scan_flat_dt(early_init_dt_scan_phyp_dump, NULL);
 
 	/* Retrieve various informations from the /chosen node of the
 	 * device-tree, including the platform type, initrd location and
@@ -1043,6 +1092,7 @@ void __init early_init_devtree(void *par
 	reserve_kdump_trampoline();
 	reserve_crashkernel();
 	early_reserve_mem();
+	reserve_crashed_mem();
 
 	lmb_enforce_memory_limit(memory_limit);
 	lmb_analyze();
Index: 2.6.24-rc5/arch/powerpc/kernel/rtas.c
===================================================================
--- 2.6.24-rc5.orig/arch/powerpc/kernel/rtas.c	2008-02-12 06:12:10.000000000 -0600
+++ 2.6.24-rc5/arch/powerpc/kernel/rtas.c	2008-02-12 06:12:37.000000000 -0600
@@ -39,6 +39,7 @@
 #include <asm/syscalls.h>
 #include <asm/smp.h>
 #include <asm/atomic.h>
+#include <asm/phyp_dump.h>
 
 struct rtas_t rtas = {
 	.lock = SPIN_LOCK_UNLOCKED
@@ -883,6 +884,37 @@ void __init rtas_initialize(void)
 #endif
 }
 
+int __init early_init_dt_scan_phyp_dump(unsigned long node,
+		const char *uname, int depth, void *data)
+{
+#ifdef CONFIG_PHYP_DUMP
+	const unsigned int *sizes;
+
+	phyp_dump_info->phyp_dump_configured = 0;
+	phyp_dump_info->phyp_dump_is_active = 0;
+
+	if (depth != 1 || strcmp(uname, "rtas") != 0)
+		return 0;
+
+	if (of_get_flat_dt_prop(node, "ibm,configure-kernel-dump", NULL))
+		phyp_dump_info->phyp_dump_configured++;
+
+	if (of_get_flat_dt_prop(node, "ibm,dump-kernel", NULL))
+		phyp_dump_info->phyp_dump_is_active++;
+
+	sizes = of_get_flat_dt_prop(node, "ibm,configure-kernel-dump-sizes", NULL);
+	if (!sizes)
+		return 0;
+
+	if (sizes[0] == 1)
+		phyp_dump_info->cpu_state_size = *((unsigned long *)&sizes[1]);
+
+	if (sizes[3] == 2)
+		phyp_dump_info->hpte_region_size = *((unsigned long *)&sizes[4]);
+#endif
+	return 1;
+}
+
 int __init early_init_dt_scan_rtas(unsigned long node,
 		const char *uname, int depth, void *data)
 {
Index: 2.6.24-rc5/include/asm/rtas.h
===================================================================
--- 2.6.24-rc5.orig/include/asm/rtas.h	2008-02-12 06:12:10.000000000 -0600
+++ 2.6.24-rc5/include/asm/rtas.h	2008-02-12 06:12:37.000000000 -0600
@@ -183,6 +183,9 @@ extern unsigned int rtas_busy_delay(int 
 
 extern int early_init_dt_scan_rtas(unsigned long node,
 		const char *uname, int depth, void *data);
+int early_init_dt_scan_phyp_dump(unsigned long node,
+		const char *uname, int depth, void *data);
+
 
 extern void pSeries_log_error(char *buf, unsigned int err_type, int fatal);
 

Re: [PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Michael Ellerman]

[-- Attachment #1: Type: text/plain, Size: 1164 bytes --]


On Tue, 2008-02-12 at 01:08 -0600, Manish Ahuja wrote:
> Initial patch for reserving memory in early boot, and freeing it later.
> If the previous boot had ended with a crash, the reserved memory would contain
> a copy of the crashed kernel data.
> 
> Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
> Signed-off-by: Linas Vepstas <linas@austin.ibm.com>
> 
> ----
>  arch/powerpc/kernel/prom.c                 |   50 ++++++++++++++++++++
>  arch/powerpc/kernel/rtas.c                 |   32 +++++++++++++
>  arch/powerpc/platforms/pseries/Makefile    |    1 
>  arch/powerpc/platforms/pseries/phyp_dump.c |   71 +++++++++++++++++++++++++++++
>  include/asm-powerpc/phyp_dump.h            |   38 +++++++++++++++
>  include/asm/rtas.h                         |    3 +
   ^^^^^^^^^^^^^^^^^^

asm/rtas.h doesn't exist. You need to clean your tree, and patch
asm-powerpc/rtas.h instead.

cheers

-- 
Michael Ellerman
OzLabs, IBM Australia Development Lab

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person

[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 189 bytes --]

[PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Manish Ahuja]

Michael,

Fixed.

-Manish


----------
Initial patch for reserving memory in early boot, and freeing it later.
If the previous boot had ended with a crash, the reserved memory would contain
a copy of the crashed kernel data.

Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
Signed-off-by: Linas Vepstas <linas@austin.ibm.com>

----
 arch/powerpc/kernel/prom.c                 |   50 ++++++++++++++++++++
 arch/powerpc/kernel/rtas.c                 |   32 +++++++++++++
 arch/powerpc/platforms/pseries/Makefile    |    1 
 arch/powerpc/platforms/pseries/phyp_dump.c |   71 +++++++++++++++++++++++++++++
 include/asm-powerpc/phyp_dump.h            |   38 +++++++++++++++
 include/asm-powerpc/rtas.h                 |    3 +
 6 files changed, 195 insertions(+)

Index: 2.6.24-rc5/include/asm-powerpc/phyp_dump.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ 2.6.24-rc5/include/asm-powerpc/phyp_dump.h	2008-02-12 16:12:45.000000000 -0600
@@ -0,0 +1,38 @@
+/*
+ * Hypervisor-assisted dump
+ *
+ * Linas Vepstas, Manish Ahuja 2007
+ * Copyright (c) 2007 IBM Corp.
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _PPC64_PHYP_DUMP_H
+#define _PPC64_PHYP_DUMP_H
+
+#ifdef CONFIG_PHYP_DUMP
+
+/* The RMR region will be saved for later dumping
+ * whenever the kernel crashes. Set this to 256MB. */
+#define PHYP_DUMP_RMR_START 0x0
+#define PHYP_DUMP_RMR_END   (1UL<<28)
+
+struct phyp_dump {
+	/* Memory that is reserved during very early boot. */
+	unsigned long init_reserve_start;
+	unsigned long init_reserve_size;
+	/* Check status during boot if dump supported, active & present*/
+	unsigned long phyp_dump_configured;
+	unsigned long phyp_dump_is_active;
+	/* store cpu & hpte size */
+	unsigned long cpu_state_size;
+	unsigned long hpte_region_size;
+};
+
+extern struct phyp_dump *phyp_dump_info;
+
+#endif /* CONFIG_PHYP_DUMP */
+#endif /* _PPC64_PHYP_DUMP_H */
Index: 2.6.24-rc5/arch/powerpc/platforms/pseries/phyp_dump.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ 2.6.24-rc5/arch/powerpc/platforms/pseries/phyp_dump.c	2008-02-12 16:12:45.000000000 -0600
@@ -0,0 +1,71 @@
+/*
+ * Hypervisor-assisted dump
+ *
+ * Linas Vepstas, Manish Ahuja 2007
+ * Copyrhgit (c) 2007 IBM Corp.
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/pfn.h>
+#include <linux/swap.h>
+
+#include <asm/page.h>
+#include <asm/phyp_dump.h>
+
+/* Global, used to communicate data between early boot and late boot */
+static struct phyp_dump phyp_dump_global;
+struct phyp_dump *phyp_dump_info = &phyp_dump_global;
+
+/**
+ * release_memory_range -- release memory previously lmb_reserved
+ * @start_pfn: starting physical frame number
+ * @nr_pages: number of pages to free.
+ *
+ * This routine will release memory that had been previously
+ * lmb_reserved in early boot. The released memory becomes
+ * available for genreal use.
+ */
+static void
+release_memory_range(unsigned long start_pfn, unsigned long nr_pages)
+{
+	struct page *rpage;
+	unsigned long end_pfn;
+	long i;
+
+	end_pfn = start_pfn + nr_pages;
+
+	for (i=start_pfn; i <= end_pfn; i++) {
+		rpage = pfn_to_page(i);
+		if (PageReserved(rpage)) {
+			ClearPageReserved(rpage);
+			init_page_count(rpage);
+			__free_page(rpage);
+			totalram_pages++;
+		}
+	}
+}
+
+static int __init phyp_dump_setup(void)
+{
+	unsigned long start_pfn, nr_pages;
+
+	/* If no memory was reserved in early boot, there is nothing to do */
+	if (phyp_dump_info->init_reserve_size == 0)
+		return 0;
+
+	/* Release memory that was reserved in early boot */
+	start_pfn = PFN_DOWN(phyp_dump_info->init_reserve_start);
+	nr_pages = PFN_DOWN(phyp_dump_info->init_reserve_size);
+	release_memory_range(start_pfn, nr_pages);
+
+	return 0;
+}
+
+subsys_initcall(phyp_dump_setup);
Index: 2.6.24-rc5/arch/powerpc/platforms/pseries/Makefile
===================================================================
--- 2.6.24-rc5.orig/arch/powerpc/platforms/pseries/Makefile	2008-02-12 16:11:44.000000000 -0600
+++ 2.6.24-rc5/arch/powerpc/platforms/pseries/Makefile	2008-02-12 16:12:45.000000000 -0600
@@ -18,3 +18,4 @@ obj-$(CONFIG_HOTPLUG_CPU)	+= hotplug-cpu
 obj-$(CONFIG_HVC_CONSOLE)	+= hvconsole.o
 obj-$(CONFIG_HVCS)		+= hvcserver.o
 obj-$(CONFIG_HCALL_STATS)	+= hvCall_inst.o
+obj-$(CONFIG_PHYP_DUMP)	+= phyp_dump.o
Index: 2.6.24-rc5/arch/powerpc/kernel/prom.c
===================================================================
--- 2.6.24-rc5.orig/arch/powerpc/kernel/prom.c	2008-02-12 16:11:44.000000000 -0600
+++ 2.6.24-rc5/arch/powerpc/kernel/prom.c	2008-02-12 16:12:45.000000000 -0600
@@ -51,6 +51,7 @@
 #include <asm/machdep.h>
 #include <asm/pSeries_reconfig.h>
 #include <asm/pci-bridge.h>
+#include <asm/phyp_dump.h>
 #include <asm/kexec.h>
 
 #ifdef DEBUG
@@ -1011,6 +1012,52 @@ static void __init early_reserve_mem(voi
 #endif
 }
 
+#ifdef CONFIG_PHYP_DUMP
+/**
+ * reserve_crashed_mem() - reserve all not-yet-dumped mmemory
+ *
+ * This routine may reserve memory regions in the kernel only
+ * if the system is supported and a dump was taken in last
+ * boot instance or if the hardware is supported and the
+ * scratch area needs to be setup. In other instances it returns
+ * without reserving anything. The memory in case of dump being
+ * active is freed when the dump is collected (by userland tools).
+ */
+static void __init reserve_crashed_mem(void)
+{
+	unsigned long base, size;
+	if (!phyp_dump_info->phyp_dump_configured) {
+		printk(KERN_ERR "Phyp-dump not supported on this hardware\n");
+		return;
+	}
+
+	if (phyp_dump_info->phyp_dump_is_active) {
+		/* Reserve *everything* above RMR.Area freed by userland tools*/
+		base = PHYP_DUMP_RMR_END;
+		size = lmb_end_of_DRAM() - base;
+
+		/* XXX crashed_ram_end is wrong, since it may be beyond
+	 	* the memory_limit, it will need to be adjusted. */
+		lmb_reserve(base, size);
+
+		phyp_dump_info->init_reserve_start = base;
+		phyp_dump_info->init_reserve_size = size;
+	}
+	else {
+		size = phyp_dump_info->cpu_state_size +
+			phyp_dump_info->hpte_region_size +
+			PHYP_DUMP_RMR_END;
+		base = lmb_end_of_DRAM() - size;
+		lmb_reserve(base, size);
+		phyp_dump_info->init_reserve_start = base;
+		phyp_dump_info->init_reserve_size = size;
+	}
+}
+#else
+static inline void __init reserve_crashed_mem(void) {}
+#endif /* CONFIG_PHYP_DUMP */
+
+
 void __init early_init_devtree(void *params)
 {
 	DBG(" -> early_init_devtree(%p)\n", params);
@@ -1022,6 +1069,8 @@ void __init early_init_devtree(void *par
 	/* Some machines might need RTAS info for debugging, grab it now. */
 	of_scan_flat_dt(early_init_dt_scan_rtas, NULL);
 #endif
+	/* scan tree to see if dump occured during last boot */
+	of_scan_flat_dt(early_init_dt_scan_phyp_dump, NULL);
 
 	/* Retrieve various informations from the /chosen node of the
 	 * device-tree, including the platform type, initrd location and
@@ -1043,6 +1092,7 @@ void __init early_init_devtree(void *par
 	reserve_kdump_trampoline();
 	reserve_crashkernel();
 	early_reserve_mem();
+	reserve_crashed_mem();
 
 	lmb_enforce_memory_limit(memory_limit);
 	lmb_analyze();
Index: 2.6.24-rc5/arch/powerpc/kernel/rtas.c
===================================================================
--- 2.6.24-rc5.orig/arch/powerpc/kernel/rtas.c	2008-02-12 16:11:44.000000000 -0600
+++ 2.6.24-rc5/arch/powerpc/kernel/rtas.c	2008-02-12 16:12:45.000000000 -0600
@@ -39,6 +39,7 @@
 #include <asm/syscalls.h>
 #include <asm/smp.h>
 #include <asm/atomic.h>
+#include <asm/phyp_dump.h>
 
 struct rtas_t rtas = {
 	.lock = SPIN_LOCK_UNLOCKED
@@ -883,6 +884,37 @@ void __init rtas_initialize(void)
 #endif
 }
 
+int __init early_init_dt_scan_phyp_dump(unsigned long node,
+		const char *uname, int depth, void *data)
+{
+#ifdef CONFIG_PHYP_DUMP
+	const unsigned int *sizes;
+
+	phyp_dump_info->phyp_dump_configured = 0;
+	phyp_dump_info->phyp_dump_is_active = 0;
+
+	if (depth != 1 || strcmp(uname, "rtas") != 0)
+		return 0;
+
+	if (of_get_flat_dt_prop(node, "ibm,configure-kernel-dump", NULL))
+		phyp_dump_info->phyp_dump_configured++;
+
+	if (of_get_flat_dt_prop(node, "ibm,dump-kernel", NULL))
+		phyp_dump_info->phyp_dump_is_active++;
+
+	sizes = of_get_flat_dt_prop(node, "ibm,configure-kernel-dump-sizes", NULL);
+	if (!sizes)
+		return 0;
+
+	if (sizes[0] == 1)
+		phyp_dump_info->cpu_state_size = *((unsigned long *)&sizes[1]);
+
+	if (sizes[3] == 2)
+		phyp_dump_info->hpte_region_size = *((unsigned long *)&sizes[4]);
+#endif
+	return 1;
+}
+
 int __init early_init_dt_scan_rtas(unsigned long node,
 		const char *uname, int depth, void *data)
 {
Index: 2.6.24-rc5/include/asm-powerpc/rtas.h
===================================================================
--- 2.6.24-rc5.orig/include/asm-powerpc/rtas.h	2008-02-12 16:09:48.000000000 -0600
+++ 2.6.24-rc5/include/asm-powerpc/rtas.h	2008-02-12 16:12:45.000000000 -0600
@@ -183,6 +183,9 @@ extern unsigned int rtas_busy_delay(int 
 
 extern int early_init_dt_scan_rtas(unsigned long node,
 		const char *uname, int depth, void *data);
+int early_init_dt_scan_phyp_dump(unsigned long node,
+		const char *uname, int depth, void *data);
+
 
 extern void pSeries_log_error(char *buf, unsigned int err_type, int fatal);
 

Re: [PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Tony Breeds]

On Tue, Feb 12, 2008 at 01:08:25AM -0600, Manish Ahuja wrote:
> 
> Initial patch for reserving memory in early boot, and freeing it later.
> If the previous boot had ended with a crash, the reserved memory would contain
> a copy of the crashed kernel data.
> 
> Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
> Signed-off-by: Linas Vepstas <linas@austin.ibm.com>
> 
> ----
>  arch/powerpc/kernel/prom.c                 |   50 ++++++++++++++++++++
>  arch/powerpc/kernel/rtas.c                 |   32 +++++++++++++
>  arch/powerpc/platforms/pseries/Makefile    |    1 
>  arch/powerpc/platforms/pseries/phyp_dump.c |   71 +++++++++++++++++++++++++++++
>  include/asm-powerpc/phyp_dump.h            |   38 +++++++++++++++
>  include/asm/rtas.h                         |    3 +
>  6 files changed, 195 insertions(+)
> 
> Index: 2.6.24-rc5/include/asm-powerpc/phyp_dump.h
> ===================================================================
> --- /dev/null	1970-01-01 00:00:00.000000000 +0000
> +++ 2.6.24-rc5/include/asm-powerpc/phyp_dump.h	2008-02-12 06:12:37.000000000 -0600
> @@ -0,0 +1,38 @@
> +/*
> + * Hypervisor-assisted dump
> + *
> + * Linas Vepstas, Manish Ahuja 2007
> + * Copyright (c) 2007 IBM Corp.

Hi Manish,
	Sorry for the minor nits but this should be:

---
 * Linas Vepstas, Manish Ahuja 2008
 * Copyright 2008 IBM Corp.
---

You can optionally use the '©' symbol after word 'Copyright' but you
shouldn't use '(c)' anymore.

Also in at least one place you've misspelt "Copyright"

Yours Tony

  linux.conf.au        http://linux.conf.au/ || http://lca2008.linux.org.au/
  Jan 28 - Feb 02 2008 The Australian Linux Technical Conference!

Re: [PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Olof Johansson]

On Thu, Feb 14, 2008 at 02:46:21PM +1100, Tony Breeds wrote:

> Hi Manish,
> 	Sorry for the minor nits but this should be:
> 
> ---
>  * Linas Vepstas, Manish Ahuja 2008
>  * Copyright 2008 IBM Corp.
> ---
> 
> You can optionally use the '??' symbol after word 'Copyright' but you
> shouldn't use '(c)' anymore.
> 
> Also in at least one place you've misspelt "Copyright"

If we're going to nitpick, then I'd like to point out that the whole
series needs to be run through checkpatch and at least the whitespace
issues should be taken care of.

I'm still not convinced that this is a useful feature compared to
hardening kdump, especially now that ehea can handle kexec/kdump (patch
posted the other day). But in the end it's up to Paul if he wants to
take it or not, not me.


-Olof

Re: [PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Manish Ahuja]

Olof,

I will run it through checkpatch before resubmitting.

Thanks,
Manish



Olof Johansson wrote:
> On Thu, Feb 14, 2008 at 02:46:21PM +1100, Tony Breeds wrote:
> 
>> Hi Manish,
>> 	Sorry for the minor nits but this should be:
>>
>> ---
>>  * Linas Vepstas, Manish Ahuja 2008
>>  * Copyright 2008 IBM Corp.
>> ---
>>
>> You can optionally use the '??' symbol after word 'Copyright' but you
>> shouldn't use '(c)' anymore.
>>
>> Also in at least one place you've misspelt "Copyright"
> 
> If we're going to nitpick, then I'd like to point out that the whole
> series needs to be run through checkpatch and at least the whitespace
> issues should be taken care of.
> 
> I'm still not convinced that this is a useful feature compared to
> hardening kdump, especially now that ehea can handle kexec/kdump (patch
> posted the other day). But in the end it's up to Paul if he wants to
> take it or not, not me.
> 
> 
> -Olof

[PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Manish Ahuja]

Initial patch for reserving memory in early boot, and freeing it later.
If the previous boot had ended with a crash, the reserved memory would contain
a copy of the crashed kernel data.

Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
Signed-off-by: Linas Vepstas <linasvepstas@gmail.com>

----
 arch/powerpc/kernel/prom.c                 |   49 ++++++++++++++++++++
 arch/powerpc/kernel/rtas.c                 |   34 +++++++++++++
 arch/powerpc/platforms/pseries/Makefile    |    1 
 arch/powerpc/platforms/pseries/phyp_dump.c |   71 +++++++++++++++++++++++++++++
 include/asm-powerpc/phyp_dump.h            |   38 +++++++++++++++
 include/asm-powerpc/rtas.h                 |    3 +
 6 files changed, 196 insertions(+)

Index: 2.6.25-rc1/include/asm-powerpc/phyp_dump.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ 2.6.25-rc1/include/asm-powerpc/phyp_dump.h	2008-02-18 04:30:28.000000000 -0600
@@ -0,0 +1,38 @@
+/*
+ * Hypervisor-assisted dump
+ *
+ * Linas Vepstas, Manish Ahuja 2008
+ * Copyright 2008 IBM Corp.
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _PPC64_PHYP_DUMP_H
+#define _PPC64_PHYP_DUMP_H
+
+#ifdef CONFIG_PHYP_DUMP
+
+/* The RMR region will be saved for later dumping
+ * whenever the kernel crashes. Set this to 256MB. */
+#define PHYP_DUMP_RMR_START 0x0
+#define PHYP_DUMP_RMR_END   (1UL<<28)
+
+struct phyp_dump {
+	/* Memory that is reserved during very early boot. */
+	unsigned long init_reserve_start;
+	unsigned long init_reserve_size;
+	/* Check status during boot if dump supported, active & present*/
+	unsigned long phyp_dump_configured;
+	unsigned long phyp_dump_is_active;
+	/* store cpu & hpte size */
+	unsigned long cpu_state_size;
+	unsigned long hpte_region_size;
+};
+
+extern struct phyp_dump *phyp_dump_info;
+
+#endif /* CONFIG_PHYP_DUMP */
+#endif /* _PPC64_PHYP_DUMP_H */
Index: 2.6.25-rc1/arch/powerpc/platforms/pseries/phyp_dump.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ 2.6.25-rc1/arch/powerpc/platforms/pseries/phyp_dump.c	2008-02-18 04:32:17.000000000 -0600
@@ -0,0 +1,71 @@
+/*
+ * Hypervisor-assisted dump
+ *
+ * Linas Vepstas, Manish Ahuja 2008
+ * Copyright 2008 IBM Corp.
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/pfn.h>
+#include <linux/swap.h>
+
+#include <asm/page.h>
+#include <asm/phyp_dump.h>
+#include <asm/machdep.h>
+
+/* Global, used to communicate data between early boot and late boot */
+static struct phyp_dump phyp_dump_global;
+struct phyp_dump *phyp_dump_info = &phyp_dump_global;
+
+/**
+ * release_memory_range -- release memory previously lmb_reserved
+ * @start_pfn: starting physical frame number
+ * @nr_pages: number of pages to free.
+ *
+ * This routine will release memory that had been previously
+ * lmb_reserved in early boot. The released memory becomes
+ * available for genreal use.
+ */
+static void
+release_memory_range(unsigned long start_pfn, unsigned long nr_pages)
+{
+	struct page *rpage;
+	unsigned long end_pfn;
+	long i;
+
+	end_pfn = start_pfn + nr_pages;
+
+	for (i = start_pfn; i <= end_pfn; i++) {
+		rpage = pfn_to_page(i);
+		if (PageReserved(rpage)) {
+			ClearPageReserved(rpage);
+			init_page_count(rpage);
+			__free_page(rpage);
+			totalram_pages++;
+		}
+	}
+}
+
+static int __init phyp_dump_setup(void)
+{
+	unsigned long start_pfn, nr_pages;
+
+	/* If no memory was reserved in early boot, there is nothing to do */
+	if (phyp_dump_info->init_reserve_size == 0)
+		return 0;
+
+	/* Release memory that was reserved in early boot */
+	start_pfn = PFN_DOWN(phyp_dump_info->init_reserve_start);
+	nr_pages = PFN_DOWN(phyp_dump_info->init_reserve_size);
+	release_memory_range(start_pfn, nr_pages);
+
+	return 0;
+}
+machine_subsys_initcall(pseries, phyp_dump_setup);
Index: 2.6.25-rc1/arch/powerpc/platforms/pseries/Makefile
===================================================================
--- 2.6.25-rc1.orig/arch/powerpc/platforms/pseries/Makefile	2008-02-18 03:22:06.000000000 -0600
+++ 2.6.25-rc1/arch/powerpc/platforms/pseries/Makefile	2008-02-18 03:23:47.000000000 -0600
@@ -18,3 +18,4 @@ obj-$(CONFIG_HOTPLUG_CPU)	+= hotplug-cpu
 obj-$(CONFIG_HVC_CONSOLE)	+= hvconsole.o
 obj-$(CONFIG_HVCS)		+= hvcserver.o
 obj-$(CONFIG_HCALL_STATS)	+= hvCall_inst.o
+obj-$(CONFIG_PHYP_DUMP)	+= phyp_dump.o
Index: 2.6.25-rc1/arch/powerpc/kernel/prom.c
===================================================================
--- 2.6.25-rc1.orig/arch/powerpc/kernel/prom.c	2008-02-18 03:22:06.000000000 -0600
+++ 2.6.25-rc1/arch/powerpc/kernel/prom.c	2008-02-18 03:23:47.000000000 -0600
@@ -51,6 +51,7 @@
 #include <asm/machdep.h>
 #include <asm/pSeries_reconfig.h>
 #include <asm/pci-bridge.h>
+#include <asm/phyp_dump.h>
 #include <asm/kexec.h>
 
 #ifdef DEBUG
@@ -1039,6 +1040,51 @@ static void __init early_reserve_mem(voi
 #endif
 }
 
+#ifdef CONFIG_PHYP_DUMP
+/**
+ * reserve_crashed_mem() - reserve all not-yet-dumped mmemory
+ *
+ * This routine may reserve memory regions in the kernel only
+ * if the system is supported and a dump was taken in last
+ * boot instance or if the hardware is supported and the
+ * scratch area needs to be setup. In other instances it returns
+ * without reserving anything. The memory in case of dump being
+ * active is freed when the dump is collected (by userland tools).
+ */
+static void __init reserve_crashed_mem(void)
+{
+	unsigned long base, size;
+	if (!phyp_dump_info->phyp_dump_configured) {
+		printk(KERN_ERR "Phyp-dump not supported on this hardware\n");
+		return;
+	}
+
+	if (phyp_dump_info->phyp_dump_is_active) {
+		/* Reserve *everything* above RMR.Area freed by userland tools*/
+		base = PHYP_DUMP_RMR_END;
+		size = lmb_end_of_DRAM() - base;
+
+		/* XXX crashed_ram_end is wrong, since it may be beyond
+		 * the memory_limit, it will need to be adjusted. */
+		lmb_reserve(base, size);
+
+		phyp_dump_info->init_reserve_start = base;
+		phyp_dump_info->init_reserve_size = size;
+	} else {
+		size = phyp_dump_info->cpu_state_size +
+			phyp_dump_info->hpte_region_size +
+			PHYP_DUMP_RMR_END;
+		base = lmb_end_of_DRAM() - size;
+		lmb_reserve(base, size);
+		phyp_dump_info->init_reserve_start = base;
+		phyp_dump_info->init_reserve_size = size;
+	}
+}
+#else
+static inline void __init reserve_crashed_mem(void) {}
+#endif /* CONFIG_PHYP_DUMP */
+
+
 void __init early_init_devtree(void *params)
 {
 	DBG(" -> early_init_devtree(%p)\n", params);
@@ -1050,6 +1096,8 @@ void __init early_init_devtree(void *par
 	/* Some machines might need RTAS info for debugging, grab it now. */
 	of_scan_flat_dt(early_init_dt_scan_rtas, NULL);
 #endif
+	/* scan tree to see if dump occured during last boot */
+	of_scan_flat_dt(early_init_dt_scan_phyp_dump, NULL);
 
 	/* Retrieve various informations from the /chosen node of the
 	 * device-tree, including the platform type, initrd location and
@@ -1071,6 +1119,7 @@ void __init early_init_devtree(void *par
 	reserve_kdump_trampoline();
 	reserve_crashkernel();
 	early_reserve_mem();
+	reserve_crashed_mem();
 
 	lmb_enforce_memory_limit(memory_limit);
 	lmb_analyze();
Index: 2.6.25-rc1/arch/powerpc/kernel/rtas.c
===================================================================
--- 2.6.25-rc1.orig/arch/powerpc/kernel/rtas.c	2008-02-18 03:22:06.000000000 -0600
+++ 2.6.25-rc1/arch/powerpc/kernel/rtas.c	2008-02-18 03:23:47.000000000 -0600
@@ -39,6 +39,7 @@
 #include <asm/syscalls.h>
 #include <asm/smp.h>
 #include <asm/atomic.h>
+#include <asm/phyp_dump.h>
 
 struct rtas_t rtas = {
 	.lock = SPIN_LOCK_UNLOCKED
@@ -883,6 +884,39 @@ void __init rtas_initialize(void)
 #endif
 }
 
+int __init early_init_dt_scan_phyp_dump(unsigned long node,
+		const char *uname, int depth, void *data)
+{
+#ifdef CONFIG_PHYP_DUMP
+	const unsigned int *sizes;
+
+	phyp_dump_info->phyp_dump_configured = 0;
+	phyp_dump_info->phyp_dump_is_active = 0;
+
+	if (depth != 1 || strcmp(uname, "rtas") != 0)
+		return 0;
+
+	if (of_get_flat_dt_prop(node, "ibm,configure-kernel-dump", NULL))
+		phyp_dump_info->phyp_dump_configured++;
+
+	if (of_get_flat_dt_prop(node, "ibm,dump-kernel", NULL))
+		phyp_dump_info->phyp_dump_is_active++;
+
+	sizes = of_get_flat_dt_prop(node, "ibm,configure-kernel-dump-sizes",
+									NULL);
+	if (!sizes)
+		return 0;
+
+	if (sizes[0] == 1)
+		phyp_dump_info->cpu_state_size = *((unsigned long *)&sizes[1]);
+
+	if (sizes[3] == 2)
+		phyp_dump_info->hpte_region_size =
+						*((unsigned long *)&sizes[4]);
+#endif
+	return 1;
+}
+
 int __init early_init_dt_scan_rtas(unsigned long node,
 		const char *uname, int depth, void *data)
 {
Index: 2.6.25-rc1/include/asm-powerpc/rtas.h
===================================================================
--- 2.6.25-rc1.orig/include/asm-powerpc/rtas.h	2008-02-18 03:22:06.000000000 -0600
+++ 2.6.25-rc1/include/asm-powerpc/rtas.h	2008-02-18 03:23:47.000000000 -0600
@@ -183,6 +183,9 @@ extern unsigned int rtas_busy_delay(int 
 
 extern int early_init_dt_scan_rtas(unsigned long node,
 		const char *uname, int depth, void *data);
+int early_init_dt_scan_phyp_dump(unsigned long node,
+		const char *uname, int depth, void *data);
+
 
 extern void pSeries_log_error(char *buf, unsigned int err_type, int fatal);
 

[PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Manish Ahuja]

Initial patch for reserving memory in early boot, and freeing it later.
If the previous boot had ended with a crash, the reserved memory would contain
a copy of the crashed kernel data.

Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
Signed-off-by: Linas Vepstas <linasvepstas@gmail.com>

----
 arch/powerpc/kernel/prom.c                 |   49 +++++++++++++
 arch/powerpc/platforms/pseries/Makefile    |    1 
 arch/powerpc/platforms/pseries/phyp_dump.c |  105 +++++++++++++++++++++++++++++
 include/asm-powerpc/phyp_dump.h            |   44 ++++++++++++
 4 files changed, 199 insertions(+)

Index: 2.6.25-rc1/include/asm-powerpc/phyp_dump.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ 2.6.25-rc1/include/asm-powerpc/phyp_dump.h	2008-02-28 22:05:25.000000000 -0600
@@ -0,0 +1,44 @@
+/*
+ * Hypervisor-assisted dump
+ *
+ * Linas Vepstas, Manish Ahuja 2008
+ * Copyright 2008 IBM Corp.
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _PPC64_PHYP_DUMP_H
+#define _PPC64_PHYP_DUMP_H
+
+#ifdef CONFIG_PHYP_DUMP
+
+/* The RMR region will be saved for later dumping
+ * whenever the kernel crashes. Set this to 256MB. */
+#define PHYP_DUMP_RMR_START 0x0
+#define PHYP_DUMP_RMR_END   (1UL<<28)
+
+struct phyp_dump {
+	/* Memory that is reserved during very early boot. */
+	unsigned long init_reserve_start;
+	unsigned long init_reserve_size;
+	/* Check status during boot if dump supported, active & present*/
+	unsigned long phyp_dump_configured;
+	unsigned long phyp_dump_is_active;
+	/* store cpu & hpte size */
+	unsigned long cpu_state_size;
+	unsigned long hpte_region_size;
+};
+
+extern struct phyp_dump *phyp_dump_info;
+
+int early_init_dt_scan_phyp_dump(unsigned long node,
+		const char *uname, int depth, void *data);
+#else /* CONFIG_PHYP_DUMP */
+int early_init_dt_scan_phyp_dump(unsigned long node,
+		const char *uname, int depth, void *data) { return 0; }
+
+#endif /* CONFIG_PHYP_DUMP */
+#endif /* _PPC64_PHYP_DUMP_H */
Index: 2.6.25-rc1/arch/powerpc/platforms/pseries/phyp_dump.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ 2.6.25-rc1/arch/powerpc/platforms/pseries/phyp_dump.c	2008-02-28 21:57:52.000000000 -0600
@@ -0,0 +1,105 @@
+/*
+ * Hypervisor-assisted dump
+ *
+ * Linas Vepstas, Manish Ahuja 2008
+ * Copyright 2008 IBM Corp.
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/pfn.h>
+#include <linux/swap.h>
+
+#include <asm/page.h>
+#include <asm/phyp_dump.h>
+#include <asm/machdep.h>
+#include <asm/prom.h>
+
+/* Global, used to communicate data between early boot and late boot */
+static struct phyp_dump phyp_dump_global;
+struct phyp_dump *phyp_dump_info = &phyp_dump_global;
+
+/**
+ * release_memory_range -- release memory previously lmb_reserved
+ * @start_pfn: starting physical frame number
+ * @nr_pages: number of pages to free.
+ *
+ * This routine will release memory that had been previously
+ * lmb_reserved in early boot. The released memory becomes
+ * available for genreal use.
+ */
+static void
+release_memory_range(unsigned long start_pfn, unsigned long nr_pages)
+{
+	struct page *rpage;
+	unsigned long end_pfn;
+	long i;
+
+	end_pfn = start_pfn + nr_pages;
+
+	for (i = start_pfn; i <= end_pfn; i++) {
+		rpage = pfn_to_page(i);
+		if (PageReserved(rpage)) {
+			ClearPageReserved(rpage);
+			init_page_count(rpage);
+			__free_page(rpage);
+			totalram_pages++;
+		}
+	}
+}
+
+static int __init phyp_dump_setup(void)
+{
+	unsigned long start_pfn, nr_pages;
+
+	/* If no memory was reserved in early boot, there is nothing to do */
+	if (phyp_dump_info->init_reserve_size == 0)
+		return 0;
+
+	/* Release memory that was reserved in early boot */
+	start_pfn = PFN_DOWN(phyp_dump_info->init_reserve_start);
+	nr_pages = PFN_DOWN(phyp_dump_info->init_reserve_size);
+	release_memory_range(start_pfn, nr_pages);
+
+	return 0;
+}
+machine_subsys_initcall(pseries, phyp_dump_setup);
+
+int __init early_init_dt_scan_phyp_dump(unsigned long node,
+		const char *uname, int depth, void *data)
+{
+#ifdef CONFIG_PHYP_DUMP
+	const unsigned int *sizes;
+
+	phyp_dump_info->phyp_dump_configured = 0;
+	phyp_dump_info->phyp_dump_is_active = 0;
+
+	if (depth != 1 || strcmp(uname, "rtas") != 0)
+		return 0;
+
+	if (of_get_flat_dt_prop(node, "ibm,configure-kernel-dump", NULL))
+		phyp_dump_info->phyp_dump_configured++;
+
+	if (of_get_flat_dt_prop(node, "ibm,dump-kernel", NULL))
+		phyp_dump_info->phyp_dump_is_active++;
+
+	sizes = of_get_flat_dt_prop(node, "ibm,configure-kernel-dump-sizes",
+									NULL);
+	if (!sizes)
+		return 0;
+
+	if (sizes[0] == 1)
+		phyp_dump_info->cpu_state_size = *((unsigned long *)&sizes[1]);
+
+	if (sizes[3] == 2)
+		phyp_dump_info->hpte_region_size =
+						*((unsigned long *)&sizes[4]);
+#endif
+	return 1;
+}
Index: 2.6.25-rc1/arch/powerpc/platforms/pseries/Makefile
===================================================================
--- 2.6.25-rc1.orig/arch/powerpc/platforms/pseries/Makefile	2008-02-28 21:54:57.000000000 -0600
+++ 2.6.25-rc1/arch/powerpc/platforms/pseries/Makefile	2008-02-28 21:55:27.000000000 -0600
@@ -18,3 +18,4 @@ obj-$(CONFIG_HOTPLUG_CPU)	+= hotplug-cpu
 obj-$(CONFIG_HVC_CONSOLE)	+= hvconsole.o
 obj-$(CONFIG_HVCS)		+= hvcserver.o
 obj-$(CONFIG_HCALL_STATS)	+= hvCall_inst.o
+obj-$(CONFIG_PHYP_DUMP)	+= phyp_dump.o
Index: 2.6.25-rc1/arch/powerpc/kernel/prom.c
===================================================================
--- 2.6.25-rc1.orig/arch/powerpc/kernel/prom.c	2008-02-28 21:54:57.000000000 -0600
+++ 2.6.25-rc1/arch/powerpc/kernel/prom.c	2008-02-28 21:55:27.000000000 -0600
@@ -51,6 +51,7 @@
 #include <asm/machdep.h>
 #include <asm/pSeries_reconfig.h>
 #include <asm/pci-bridge.h>
+#include <asm/phyp_dump.h>
 #include <asm/kexec.h>
 
 #ifdef DEBUG
@@ -1039,6 +1040,51 @@ static void __init early_reserve_mem(voi
 #endif
 }
 
+#ifdef CONFIG_PHYP_DUMP
+/**
+ * reserve_crashed_mem() - reserve all not-yet-dumped mmemory
+ *
+ * This routine may reserve memory regions in the kernel only
+ * if the system is supported and a dump was taken in last
+ * boot instance or if the hardware is supported and the
+ * scratch area needs to be setup. In other instances it returns
+ * without reserving anything. The memory in case of dump being
+ * active is freed when the dump is collected (by userland tools).
+ */
+static void __init reserve_crashed_mem(void)
+{
+	unsigned long base, size;
+	if (!phyp_dump_info->phyp_dump_configured) {
+		printk(KERN_ERR "Phyp-dump not supported on this hardware\n");
+		return;
+	}
+
+	if (phyp_dump_info->phyp_dump_is_active) {
+		/* Reserve *everything* above RMR.Area freed by userland tools*/
+		base = PHYP_DUMP_RMR_END;
+		size = lmb_end_of_DRAM() - base;
+
+		/* XXX crashed_ram_end is wrong, since it may be beyond
+		 * the memory_limit, it will need to be adjusted. */
+		lmb_reserve(base, size);
+
+		phyp_dump_info->init_reserve_start = base;
+		phyp_dump_info->init_reserve_size = size;
+	} else {
+		size = phyp_dump_info->cpu_state_size +
+			phyp_dump_info->hpte_region_size +
+			PHYP_DUMP_RMR_END;
+		base = lmb_end_of_DRAM() - size;
+		lmb_reserve(base, size);
+		phyp_dump_info->init_reserve_start = base;
+		phyp_dump_info->init_reserve_size = size;
+	}
+}
+#else
+static inline void __init reserve_crashed_mem(void) {}
+#endif /* CONFIG_PHYP_DUMP  && CONFIG_PPC_RTAS */
+
+
 void __init early_init_devtree(void *params)
 {
 	DBG(" -> early_init_devtree(%p)\n", params);
@@ -1050,6 +1096,8 @@ void __init early_init_devtree(void *par
 	/* Some machines might need RTAS info for debugging, grab it now. */
 	of_scan_flat_dt(early_init_dt_scan_rtas, NULL);
 #endif
+	/* scan tree to see if dump occured during last boot */
+	of_scan_flat_dt(early_init_dt_scan_phyp_dump, NULL);
 
 	/* Retrieve various informations from the /chosen node of the
 	 * device-tree, including the platform type, initrd location and
@@ -1071,6 +1119,7 @@ void __init early_init_devtree(void *par
 	reserve_kdump_trampoline();
 	reserve_crashkernel();
 	early_reserve_mem();
+	reserve_crashed_mem();
 
 	lmb_enforce_memory_limit(memory_limit);
 	lmb_analyze();

Re: [PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Michael Ellerman]

[-- Attachment #1: Type: text/plain, Size: 6762 bytes --]

On Thu, 2008-02-28 at 18:24 -0600, Manish Ahuja wrote:
> Initial patch for reserving memory in early boot, and freeing it later.
> If the previous boot had ended with a crash, the reserved memory would contain
> a copy of the crashed kernel data.
> 
> Signed-off-by: Manish Ahuja <mahuja@us.ibm.com>
> Signed-off-by: Linas Vepstas <linasvepstas@gmail.com>

Hi Manish,

A few comments inline ..

> Index: 2.6.25-rc1/arch/powerpc/platforms/pseries/phyp_dump.c
> ===================================================================
> --- /dev/null	1970-01-01 00:00:00.000000000 +0000
> +++ 2.6.25-rc1/arch/powerpc/platforms/pseries/phyp_dump.c	2008-02-28 21:57:52.000000000 -0600
> @@ -0,0 +1,105 @@
> +/*
> + * Hypervisor-assisted dump
> + *
> + * Linas Vepstas, Manish Ahuja 2008
> + * Copyright 2008 IBM Corp.
> + *
> + *      This program is free software; you can redistribute it and/or
> + *      modify it under the terms of the GNU General Public License
> + *      as published by the Free Software Foundation; either version
> + *      2 of the License, or (at your option) any later version.
> + *
> + */
> +
> +#include <linux/init.h>
> +#include <linux/mm.h>
> +#include <linux/pfn.h>
> +#include <linux/swap.h>
> +
> +#include <asm/page.h>
> +#include <asm/phyp_dump.h>
> +#include <asm/machdep.h>
> +#include <asm/prom.h>
> +
> +/* Global, used to communicate data between early boot and late boot */
> +static struct phyp_dump phyp_dump_global;
> +struct phyp_dump *phyp_dump_info = &phyp_dump_global;

I don't see the point of this. You have a static (ie. non-global) struct
called phyp_dump_global, then you create a pointer to it and pass that
around. It could just be:

phyp_dump.h:
extern struct phyp_dump phyp_dump_info; 

phyp_dump.c:
struct phyp_dump phyp_dump_info;

phyp_dump_info.foo = bar;

I also think the struct should be called phyp_dump_info, not phyp_dump -
it contains info about phyp_dump, not the dump itself.

> +
> +/**
> + * release_memory_range -- release memory previously lmb_reserved
> + * @start_pfn: starting physical frame number
> + * @nr_pages: number of pages to free.
> + *
> + * This routine will release memory that had been previously
> + * lmb_reserved in early boot. The released memory becomes
> + * available for genreal use.
> + */
> +static void
> +release_memory_range(unsigned long start_pfn, unsigned long nr_pages)
> +{
> +	struct page *rpage;
> +	unsigned long end_pfn;
> +	long i;
> +
> +	end_pfn = start_pfn + nr_pages;
> +
> +	for (i = start_pfn; i <= end_pfn; i++) {
> +		rpage = pfn_to_page(i);
> +		if (PageReserved(rpage)) {
> +			ClearPageReserved(rpage);
> +			init_page_count(rpage);
> +			__free_page(rpage);
> +			totalram_pages++;
> +		}
> +	}
> +}
> +
> +static int __init phyp_dump_setup(void)
> +{
> +	unsigned long start_pfn, nr_pages;
> +
> +	/* If no memory was reserved in early boot, there is nothing to do */
> +	if (phyp_dump_info->init_reserve_size == 0)
> +		return 0;
> +
> +	/* Release memory that was reserved in early boot */
> +	start_pfn = PFN_DOWN(phyp_dump_info->init_reserve_start);
> +	nr_pages = PFN_DOWN(phyp_dump_info->init_reserve_size);
> +	release_memory_range(start_pfn, nr_pages);
> +
> +	return 0;
> +}
> +machine_subsys_initcall(pseries, phyp_dump_setup);
> +
> +int __init early_init_dt_scan_phyp_dump(unsigned long node,
> +		const char *uname, int depth, void *data)
> +{
> +#ifdef CONFIG_PHYP_DUMP
> +	const unsigned int *sizes;
> +
> +	phyp_dump_info->phyp_dump_configured = 0;
> +	phyp_dump_info->phyp_dump_is_active = 0;
> +
> +	if (depth != 1 || strcmp(uname, "rtas") != 0)
> +		return 0;
> +
> +	if (of_get_flat_dt_prop(node, "ibm,configure-kernel-dump", NULL))
> +		phyp_dump_info->phyp_dump_configured++;
> +
> +	if (of_get_flat_dt_prop(node, "ibm,dump-kernel", NULL))
> +		phyp_dump_info->phyp_dump_is_active++;
> +
> +	sizes = of_get_flat_dt_prop(node, "ibm,configure-kernel-dump-sizes",
> +									NULL);
> +	if (!sizes)
> +		return 0;
> +
> +	if (sizes[0] == 1)
> +		phyp_dump_info->cpu_state_size = *((unsigned long *)&sizes[1]);
> +
> +	if (sizes[3] == 2)
> +		phyp_dump_info->hpte_region_size =
> +						*((unsigned long *)&sizes[4]);
> +#endif

This doesn't need to be inside #ifdef, you have a dummy version already
defined in the header file.

> Index: 2.6.25-rc1/arch/powerpc/kernel/prom.c
> ===================================================================
> --- 2.6.25-rc1.orig/arch/powerpc/kernel/prom.c	2008-02-28 21:54:57.000000000 -0600
> +++ 2.6.25-rc1/arch/powerpc/kernel/prom.c	2008-02-28 21:55:27.000000000 -0600
> @@ -1039,6 +1040,51 @@ static void __init early_reserve_mem(voi
>  #endif
>  }
>  
> +#ifdef CONFIG_PHYP_DUMP
> +/**
> + * reserve_crashed_mem() - reserve all not-yet-dumped mmemory
> + *
> + * This routine may reserve memory regions in the kernel only
> + * if the system is supported and a dump was taken in last
> + * boot instance or if the hardware is supported and the
> + * scratch area needs to be setup. In other instances it returns
> + * without reserving anything. The memory in case of dump being
> + * active is freed when the dump is collected (by userland tools).
> + */
> +static void __init reserve_crashed_mem(void)

This could do with a name change IMO, eg. phyp_dump_reserve_mem() or
something.

> +{
> +	unsigned long base, size;
> +	if (!phyp_dump_info->phyp_dump_configured) {
> +		printk(KERN_ERR "Phyp-dump not supported on this hardware\n");
> +		return;
> +	}
> +
> +	if (phyp_dump_info->phyp_dump_is_active) {
> +		/* Reserve *everything* above RMR.Area freed by userland tools*/
> +		base = PHYP_DUMP_RMR_END;
> +		size = lmb_end_of_DRAM() - base;
> +
> +		/* XXX crashed_ram_end is wrong, since it may be beyond
> +		 * the memory_limit, it will need to be adjusted. */
> +		lmb_reserve(base, size);
> +
> +		phyp_dump_info->init_reserve_start = base;
> +		phyp_dump_info->init_reserve_size = size;
> +	} else {
> +		size = phyp_dump_info->cpu_state_size +
> +			phyp_dump_info->hpte_region_size +
> +			PHYP_DUMP_RMR_END;
> +		base = lmb_end_of_DRAM() - size;
> +		lmb_reserve(base, size);
> +		phyp_dump_info->init_reserve_start = base;
> +		phyp_dump_info->init_reserve_size = size;
> +	}
> +}
> +#else
> +static inline void __init reserve_crashed_mem(void) {}
> +#endif /* CONFIG_PHYP_DUMP  && CONFIG_PPC_RTAS */


cheers

-- 
Michael Ellerman
OzLabs, IBM Australia Development Lab

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person

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Re: [PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Paul Mackerras]

Manish Ahuja writes:

> +#else /* CONFIG_PHYP_DUMP */
> +int early_init_dt_scan_phyp_dump(unsigned long node,
> +		const char *uname, int depth, void *data) { return 0; }

This shouldn't be in the header file.  Either put it in prom.c (and
make it return 1 so the of_scan_flat_dt call doesn't have to go
through the entire device tree), or put #ifdef CONFIG_PHYP_DUMP around
the of_scan_flat_dt call itself.

> +/* Global, used to communicate data between early boot and late boot */
> +static struct phyp_dump phyp_dump_global;
> +struct phyp_dump *phyp_dump_info = &phyp_dump_global;

It's a little weird to have a static variable with global in its name.

> +int __init early_init_dt_scan_phyp_dump(unsigned long node,
> +		const char *uname, int depth, void *data)
> +{
> +#ifdef CONFIG_PHYP_DUMP

This is in phyp_dump.c, which only gets compiled if CONFIG_PHYP_DUMP
is set, so you don't need this ifdef.

Paul.

Re: [PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Michael Ellerman]

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On Tue, 2008-03-11 at 17:12 +1100, Paul Mackerras wrote:
> Manish Ahuja writes:
> 
> > +#else /* CONFIG_PHYP_DUMP */
> > +int early_init_dt_scan_phyp_dump(unsigned long node,
> > +		const char *uname, int depth, void *data) { return 0; }
> 
> This shouldn't be in the header file.  Either put it in prom.c (and
> make it return 1 so the of_scan_flat_dt call doesn't have to go
> through the entire device tree), or put #ifdef CONFIG_PHYP_DUMP around
> the of_scan_flat_dt call itself.

It should be in the header file, otherwise we need an #ifdef around the
call site - which is uglier.

It should definitely return 1 though.

cheers

-- 
Michael Ellerman
OzLabs, IBM Australia Development Lab

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person

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Re: [PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Michael Ellerman]

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On Wed, 2008-03-12 at 11:13 +1100, Michael Ellerman wrote:
> On Tue, 2008-03-11 at 17:12 +1100, Paul Mackerras wrote:
> > Manish Ahuja writes:
> > 
> > > +#else /* CONFIG_PHYP_DUMP */
> > > +int early_init_dt_scan_phyp_dump(unsigned long node,
> > > +		const char *uname, int depth, void *data) { return 0; }
> > 
> > This shouldn't be in the header file.  Either put it in prom.c (and
> > make it return 1 so the of_scan_flat_dt call doesn't have to go
> > through the entire device tree), or put #ifdef CONFIG_PHYP_DUMP around
> > the of_scan_flat_dt call itself.
> 
> It should be in the header file, otherwise we need an #ifdef around the
> call site - which is uglier.

Right I'm an idiot. It is called via a function pointer, so a static
inline (which this should be, but isn't) is no good. An #ifdef around
the call site is probably the least ugly option given that otherwise we
have to have an empty version in the binary.

cheers

-- 
Michael Ellerman
OzLabs, IBM Australia Development Lab

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person

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Re: [PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Linas Vepstas]

On 10/03/2008, Michael Ellerman <michael@ellerman.id.au> wrote:
> On Thu, 2008-02-28 at 18:24 -0600, Manish Ahuja wrote:

>  > +
>  > +/* Global, used to communicate data between early boot and late boot */
>  > +static struct phyp_dump phyp_dump_global;
>  > +struct phyp_dump *phyp_dump_info = &phyp_dump_global;
>
> I don't see the point of this. You have a static (ie. non-global) struct
>  called phyp_dump_global, then you create a pointer to it and pass that
>  around.

I did this. This is a style used to minimize disruption due to future
design changes. Basically, the idea is that, at some later time, for
some unknown reason, we decide that this structure shouldn't
be global, or maybe shouldn't be statically allocated, or maybe
should be per-cpu, or who knows.  By creating a pointer, and
just passing that around, you isolate other code from this change.

I learned this trick after spending too many months of my life hunting
down globals and replacing them by dynamically allocated structs.
Its a long and painful process, on many levels, often requiring major
code restructuring.  Code that touches globals directly is often
poorly thought out, designed.  But going in the opposite direction
is easy: if your code always passes everything it needs as args
to subroutines,  then you are free & clear ... if one of those args
just happens to be a pointer to a global, there's no loss (not even
a performance loss -- the arg passing overhead is about the same
as a global TOC lookup!)

So it may look weird if you're not used to seeing it; but the alternative
is almost always worse.

--linas

Re: [PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Manish Ahuja]

If Mike and Paul are okay, then I will leave this bit as is and fix all 
other issues and comments.

Thanks,
Manish



Linas Vepstas wrote:
> On 10/03/2008, Michael Ellerman <michael@ellerman.id.au> wrote:
>> On Thu, 2008-02-28 at 18:24 -0600, Manish Ahuja wrote:
> 
>>  > +
>>  > +/* Global, used to communicate data between early boot and late boot */
>>  > +static struct phyp_dump phyp_dump_global;
>>  > +struct phyp_dump *phyp_dump_info = &phyp_dump_global;
>>
>> I don't see the point of this. You have a static (ie. non-global) struct
>>  called phyp_dump_global, then you create a pointer to it and pass that
>>  around.
> 
> I did this. This is a style used to minimize disruption due to future
> design changes. Basically, the idea is that, at some later time, for
> some unknown reason, we decide that this structure shouldn't
> be global, or maybe shouldn't be statically allocated, or maybe
> should be per-cpu, or who knows.  By creating a pointer, and
> just passing that around, you isolate other code from this change.
> 
> I learned this trick after spending too many months of my life hunting
> down globals and replacing them by dynamically allocated structs.
> Its a long and painful process, on many levels, often requiring major
> code restructuring.  Code that touches globals directly is often
> poorly thought out, designed.  But going in the opposite direction
> is easy: if your code always passes everything it needs as args
> to subroutines,  then you are free & clear ... if one of those args
> just happens to be a pointer to a global, there's no loss (not even
> a performance loss -- the arg passing overhead is about the same
> as a global TOC lookup!)
> 
> So it may look weird if you're not used to seeing it; but the alternative
> is almost always worse.
> 
> --linas

Re: [PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Michael Ellerman]

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On Wed, 2008-03-12 at 23:29 -0500, Manish Ahuja wrote:
> If Mike and Paul are okay, then I will leave this bit as is and fix all 
> other issues and comments.

Well I still don't like it - it uglifies the code _now_, for a potential
future benefit that may never come. But I don't care that much, if
Paul's happy with it let it go in.

cheers

> Linas Vepstas wrote:
> > On 10/03/2008, Michael Ellerman <michael@ellerman.id.au> wrote:
> >> On Thu, 2008-02-28 at 18:24 -0600, Manish Ahuja wrote:
> > 
> >>  > +
> >>  > +/* Global, used to communicate data between early boot and late boot */
> >>  > +static struct phyp_dump phyp_dump_global;
> >>  > +struct phyp_dump *phyp_dump_info = &phyp_dump_global;
> >>
> >> I don't see the point of this. You have a static (ie. non-global) struct
> >>  called phyp_dump_global, then you create a pointer to it and pass that
> >>  around.
> > 
> > I did this. This is a style used to minimize disruption due to future
> > design changes. Basically, the idea is that, at some later time, for
> > some unknown reason, we decide that this structure shouldn't
> > be global, or maybe shouldn't be statically allocated, or maybe
> > should be per-cpu, or who knows.  By creating a pointer, and
> > just passing that around, you isolate other code from this change.
> > 
> > I learned this trick after spending too many months of my life hunting
> > down globals and replacing them by dynamically allocated structs.
> > Its a long and painful process, on many levels, often requiring major
> > code restructuring.  Code that touches globals directly is often
> > poorly thought out, designed.  But going in the opposite direction
> > is easy: if your code always passes everything it needs as args
> > to subroutines,  then you are free & clear ... if one of those args
> > just happens to be a pointer to a global, there's no loss (not even
> > a performance loss -- the arg passing overhead is about the same
> > as a global TOC lookup!)
> > 
> > So it may look weird if you're not used to seeing it; but the alternative
> > is almost always worse.


-- 
Michael Ellerman
OzLabs, IBM Australia Development Lab

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person

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Re: [PATCH 2/8] pseries: phyp dump: reserve-release proof-of-concept

[Paul Mackerras]

Manish Ahuja writes:

> If Mike and Paul are okay, then I will leave this bit as is and fix all 
> other issues and comments.

Well, part of the problem is the semantic dissonance caused by having
a static variable called "global".  Please change the name
"phyp_dump_global" to "phyp_dump_vars" or something similar - that
will only affect two lines of code and will reduce the ugliness a bit.

Paul.