* [PATCH 1/3] NOMMU: Provide shared-writable mmap support on ramfs
@ 2005-11-23 18:59 David Howells
2005-11-23 18:59 ` [PATCH 3/3] FRV: Implement futex operations for FRV David Howells
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: David Howells @ 2005-11-23 18:59 UTC (permalink / raw)
To: torvalds, akpm, dalomar; +Cc: linux-kernel, uclinux-dev
The attached patch makes ramfs support shared-writable mmaps by:
(1) Attempting to perform a contiguous block allocation to the requested size
when truncate attempts to increase the file from zero size, such as
happens when:
fd = shm_open("/file/on/ramfs", ...):
ftruncate(fd, size_requested);
addr = mmap(NULL, subsize, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_SHARED,
fd, offset);
(2) Permitting any shared-writable mapping over any contiguous set of extant
pages. get_unmapped_area() will return the address into the actual ramfs
pages. The mapping may start anywhere and be of any size, but may not go
over the end of file. Multiple mappings may overlap in any way.
(3) Not permitting a file to be shrunk if it would truncate any shared
mappings (private mappings are copied).
Thus this patch provides support for POSIX shared memory on NOMMU kernels, with
certain limitations such as there being a large enough block of pages available
to support the allocation and it only working on directly mappable filesystems.
Signed-Off-By: David Howells <dhowells@redhat.com>
---
warthog>diffstat -p1 shmem-ramfs-2615rc2.diff
fs/ramfs/Makefile | 4
fs/ramfs/file-mmu.c | 57 +++++++++
fs/ramfs/file-nommu.c | 294 ++++++++++++++++++++++++++++++++++++++++++++++++++
fs/ramfs/inode.c | 22 ---
fs/ramfs/internal.h | 15 ++
include/linux/ramfs.h | 10 +
6 files changed, 380 insertions(+), 22 deletions(-)
diff -uNrp linux-2.6.15-rc2-frv/fs/ramfs/file-mmu.c linux-2.6.15-rc2-frv-shmem/fs/ramfs/file-mmu.c
--- linux-2.6.15-rc2-frv/fs/ramfs/file-mmu.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.15-rc2-frv-shmem/fs/ramfs/file-mmu.c 2005-11-23 16:00:57.000000000 +0000
@@ -0,0 +1,57 @@
+/* file-mmu.c: ramfs MMU-based file operations
+ *
+ * Resizable simple ram filesystem for Linux.
+ *
+ * Copyright (C) 2000 Linus Torvalds.
+ * 2000 Transmeta Corp.
+ *
+ * Usage limits added by David Gibson, Linuxcare Australia.
+ * This file is released under the GPL.
+ */
+
+/*
+ * NOTE! This filesystem is probably most useful
+ * not as a real filesystem, but as an example of
+ * how virtual filesystems can be written.
+ *
+ * It doesn't get much simpler than this. Consider
+ * that this file implements the full semantics of
+ * a POSIX-compliant read-write filesystem.
+ *
+ * Note in particular how the filesystem does not
+ * need to implement any data structures of its own
+ * to keep track of the virtual data: using the VFS
+ * caches is sufficient.
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/smp_lock.h>
+#include <linux/backing-dev.h>
+#include <linux/ramfs.h>
+
+#include <asm/uaccess.h>
+#include "internal.h"
+
+struct address_space_operations ramfs_aops = {
+ .readpage = simple_readpage,
+ .prepare_write = simple_prepare_write,
+ .commit_write = simple_commit_write
+};
+
+struct file_operations ramfs_file_operations = {
+ .read = generic_file_read,
+ .write = generic_file_write,
+ .mmap = generic_file_mmap,
+ .fsync = simple_sync_file,
+ .sendfile = generic_file_sendfile,
+ .llseek = generic_file_llseek,
+};
+
+struct inode_operations ramfs_file_inode_operations = {
+ .getattr = simple_getattr,
+};
diff -uNrp linux-2.6.15-rc2-frv/fs/ramfs/file-nommu.c linux-2.6.15-rc2-frv-shmem/fs/ramfs/file-nommu.c
--- linux-2.6.15-rc2-frv/fs/ramfs/file-nommu.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.15-rc2-frv-shmem/fs/ramfs/file-nommu.c 2005-11-23 16:24:36.000000000 +0000
@@ -0,0 +1,294 @@
+/* file-nommu.c: no-MMU version of ramfs
+ *
+ * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * 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/module.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/smp_lock.h>
+#include <linux/backing-dev.h>
+#include <linux/ramfs.h>
+#include <linux/quotaops.h>
+#include <linux/pagevec.h>
+#include <linux/mman.h>
+
+#include <asm/uaccess.h>
+#include "internal.h"
+
+static int ramfs_nommu_setattr(struct dentry *, struct iattr *);
+
+struct address_space_operations ramfs_aops = {
+ .readpage = simple_readpage,
+ .prepare_write = simple_prepare_write,
+ .commit_write = simple_commit_write
+};
+
+struct file_operations ramfs_file_operations = {
+ .mmap = ramfs_nommu_mmap,
+ .get_unmapped_area = ramfs_nommu_get_unmapped_area,
+ .read = generic_file_read,
+ .write = generic_file_write,
+ .fsync = simple_sync_file,
+ .sendfile = generic_file_sendfile,
+ .llseek = generic_file_llseek,
+};
+
+struct inode_operations ramfs_file_inode_operations = {
+ .setattr = ramfs_nommu_setattr,
+ .getattr = simple_getattr,
+};
+
+/*****************************************************************************/
+/*
+ * add a contiguous set of pages into a ramfs inode when it's truncated from
+ * size 0 on the assumption that it's going to be used for an mmap of shared
+ * memory
+ */
+static int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize)
+{
+ struct pagevec lru_pvec;
+ unsigned long npages, xpages, loop, limit;
+ struct page *pages;
+ unsigned order;
+ void *data;
+ int ret;
+
+ /* make various checks */
+ order = get_order(newsize);
+ if (unlikely(order >= MAX_ORDER))
+ goto too_big;
+
+ limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
+ if (limit != RLIM_INFINITY && newsize > limit)
+ goto fsize_exceeded;
+
+ if (newsize > inode->i_sb->s_maxbytes)
+ goto too_big;
+
+ i_size_write(inode, newsize);
+
+ /* allocate enough contiguous pages to be able to satisfy the
+ * request */
+ pages = alloc_pages(mapping_gfp_mask(inode->i_mapping), order);
+ if (!pages)
+ return -ENOMEM;
+
+ /* split the high-order page into an array of single pages */
+ xpages = 1UL << order;
+ npages = (newsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
+
+ for (loop = 0; loop < npages; loop++)
+ set_page_count(pages + loop, 1);
+
+ /* trim off any pages we don't actually require */
+ for (loop = npages; loop < xpages; loop++)
+ __free_page(pages + loop);
+
+ /* clear the memory we allocated */
+ newsize = PAGE_SIZE * npages;
+ data = page_address(pages);
+ memset(data, 0, newsize);
+
+ /* attach all the pages to the inode's address space */
+ pagevec_init(&lru_pvec, 0);
+ for (loop = 0; loop < npages; loop++) {
+ struct page *page = pages + loop;
+
+ ret = add_to_page_cache(page, inode->i_mapping, loop, GFP_KERNEL);
+ if (ret < 0)
+ goto add_error;
+
+ if (!pagevec_add(&lru_pvec, page))
+ __pagevec_lru_add(&lru_pvec);
+
+ unlock_page(page);
+ }
+
+ pagevec_lru_add(&lru_pvec);
+ return 0;
+
+ fsize_exceeded:
+ send_sig(SIGXFSZ, current, 0);
+ too_big:
+ return -EFBIG;
+
+ add_error:
+ page_cache_release(pages + loop);
+ for (loop++; loop < npages; loop++)
+ __free_page(pages + loop);
+ return ret;
+}
+
+/*****************************************************************************/
+/*
+ * check that file shrinkage doesn't leave any VMAs dangling in midair
+ */
+static int ramfs_nommu_check_mappings(struct inode *inode,
+ size_t newsize, size_t size)
+{
+ struct vm_area_struct *vma;
+ struct prio_tree_iter iter;
+
+ /* search for VMAs that fall within the dead zone */
+ vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap,
+ newsize >> PAGE_SHIFT,
+ (size + PAGE_SIZE - 1) >> PAGE_SHIFT
+ ) {
+ /* found one - only interested if it's shared out of the page
+ * cache */
+ if (vma->vm_flags & VM_SHARED)
+ return -ETXTBSY; /* not quite true, but near enough */
+ }
+
+ return 0;
+}
+
+/*****************************************************************************/
+/*
+ *
+ */
+static int ramfs_nommu_resize(struct inode *inode, loff_t newsize, loff_t size)
+{
+ int ret;
+
+ /* assume a truncate from zero size is going to be for the purposes of
+ * shared mmap */
+ if (size == 0) {
+ if (unlikely(newsize >> 32))
+ return -EFBIG;
+
+ return ramfs_nommu_expand_for_mapping(inode, newsize);
+ }
+
+ /* check that a decrease in size doesn't cut off any shared mappings */
+ if (newsize < size) {
+ ret = ramfs_nommu_check_mappings(inode, newsize, size);
+ if (ret < 0)
+ return ret;
+ }
+
+ ret = vmtruncate(inode, size);
+
+ return ret;
+}
+
+/*****************************************************************************/
+/*
+ * handle a change of attributes
+ * - we're specifically interested in a change of size
+ */
+static int ramfs_nommu_setattr(struct dentry *dentry, struct iattr *ia)
+{
+ struct inode *inode = dentry->d_inode;
+ unsigned int old_ia_valid = ia->ia_valid;
+ int ret = 0;
+
+ /* by providing our own setattr() method, we skip this quotaism */
+ if ((old_ia_valid & ATTR_UID && ia->ia_uid != inode->i_uid) ||
+ (old_ia_valid & ATTR_GID && ia->ia_gid != inode->i_gid))
+ ret = DQUOT_TRANSFER(inode, ia) ? -EDQUOT : 0;
+
+ /* pick out size-changing events */
+ if (ia->ia_valid & ATTR_SIZE) {
+ loff_t size = i_size_read(inode);
+ if (ia->ia_size != size) {
+ ret = ramfs_nommu_resize(inode, ia->ia_size, size);
+ if (ret < 0 || ia->ia_valid == ATTR_SIZE)
+ goto out;
+ } else {
+ /* we skipped the truncate but must still update
+ * timestamps
+ */
+ ia->ia_valid |= ATTR_MTIME|ATTR_CTIME;
+ }
+ }
+
+ ret = inode_setattr(inode, ia);
+ out:
+ ia->ia_valid = old_ia_valid;
+ return ret;
+}
+
+/*****************************************************************************/
+/*
+ * try to determine where a shared mapping can be made
+ * - we require that:
+ * - the pages to be mapped must exist
+ * - the pages be physically contiguous in sequence
+ */
+unsigned long ramfs_nommu_get_unmapped_area(struct file *file,
+ unsigned long addr, unsigned long len,
+ unsigned long pgoff, unsigned long flags)
+{
+ unsigned long maxpages, lpages, nr, loop, ret;
+ struct inode *inode = file->f_dentry->d_inode;
+ struct page **pages = NULL, **ptr, *page;
+ loff_t isize;
+
+ if (!(flags & MAP_SHARED))
+ return addr;
+
+ /* the mapping mustn't extend beyond the EOF */
+ lpages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ isize = i_size_read(inode);
+
+ ret = -EINVAL;
+ maxpages = (isize + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ if (pgoff >= maxpages)
+ goto out;
+
+ if (maxpages - pgoff < lpages)
+ goto out;
+
+ /* gang-find the pages */
+ ret = -ENOMEM;
+ pages = kmalloc(lpages * sizeof(struct page *), GFP_KERNEL);
+ if (!pages)
+ goto out;
+
+ memset(pages, 0, lpages * sizeof(struct page *));
+
+ nr = find_get_pages(inode->i_mapping, pgoff, lpages, pages);
+ if (nr != lpages)
+ goto out; /* leave if some pages were missing */
+
+ /* check the pages for physical adjacency */
+ ptr = pages;
+ page = *ptr++;
+ page++;
+ for (loop = lpages; loop > 1; loop--)
+ if (*ptr++ != page++)
+ goto out;
+
+ /* okay - all conditions fulfilled */
+ ret = (unsigned long) page_address(pages[0]);
+
+ out:
+ if (pages) {
+ ptr = pages;
+ for (loop = lpages; loop > 0; loop--)
+ put_page(*ptr++);
+ kfree(pages);
+ }
+
+ return ret;
+}
+
+/*****************************************************************************/
+/*
+ * set up a mapping
+ */
+int ramfs_nommu_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ return 0;
+}
diff -uNrp linux-2.6.15-rc2-frv/fs/ramfs/inode.c linux-2.6.15-rc2-frv-shmem/fs/ramfs/inode.c
--- linux-2.6.15-rc2-frv/fs/ramfs/inode.c 2005-06-22 13:52:17.000000000 +0100
+++ linux-2.6.15-rc2-frv-shmem/fs/ramfs/inode.c 2005-11-23 16:00:57.000000000 +0000
@@ -34,13 +34,12 @@
#include <linux/ramfs.h>
#include <asm/uaccess.h>
+#include "internal.h"
/* some random number */
#define RAMFS_MAGIC 0x858458f6
static struct super_operations ramfs_ops;
-static struct address_space_operations ramfs_aops;
-static struct inode_operations ramfs_file_inode_operations;
static struct inode_operations ramfs_dir_inode_operations;
static struct backing_dev_info ramfs_backing_dev_info = {
@@ -142,25 +141,6 @@ static int ramfs_symlink(struct inode *
return error;
}
-static struct address_space_operations ramfs_aops = {
- .readpage = simple_readpage,
- .prepare_write = simple_prepare_write,
- .commit_write = simple_commit_write
-};
-
-struct file_operations ramfs_file_operations = {
- .read = generic_file_read,
- .write = generic_file_write,
- .mmap = generic_file_mmap,
- .fsync = simple_sync_file,
- .sendfile = generic_file_sendfile,
- .llseek = generic_file_llseek,
-};
-
-static struct inode_operations ramfs_file_inode_operations = {
- .getattr = simple_getattr,
-};
-
static struct inode_operations ramfs_dir_inode_operations = {
.create = ramfs_create,
.lookup = simple_lookup,
diff -uNrp linux-2.6.15-rc2-frv/fs/ramfs/internal.h linux-2.6.15-rc2-frv-shmem/fs/ramfs/internal.h
--- linux-2.6.15-rc2-frv/fs/ramfs/internal.h 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.15-rc2-frv-shmem/fs/ramfs/internal.h 2005-11-23 16:25:37.000000000 +0000
@@ -0,0 +1,15 @@
+/* internal.h: ramfs internal definitions
+ *
+ * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * 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.
+ */
+
+
+extern struct address_space_operations ramfs_aops;
+extern struct file_operations ramfs_file_operations;
+extern struct inode_operations ramfs_file_inode_operations;
diff -uNrp linux-2.6.15-rc2-frv/fs/ramfs/Makefile linux-2.6.15-rc2-frv-shmem/fs/ramfs/Makefile
--- linux-2.6.15-rc2-frv/fs/ramfs/Makefile 2004-06-18 13:41:28.000000000 +0100
+++ linux-2.6.15-rc2-frv-shmem/fs/ramfs/Makefile 2005-11-23 16:00:57.000000000 +0000
@@ -4,4 +4,6 @@
obj-$(CONFIG_RAMFS) += ramfs.o
-ramfs-objs := inode.o
+file-mmu-y := file-nommu.o
+file-mmu-$(CONFIG_MMU) := file-mmu.o
+ramfs-objs += inode.o $(file-mmu-y)
diff -uNrp linux-2.6.15-rc2-frv/include/linux/ramfs.h linux-2.6.15-rc2-frv-shmem/include/linux/ramfs.h
--- linux-2.6.15-rc2-frv/include/linux/ramfs.h 2004-10-19 10:42:17.000000000 +0100
+++ linux-2.6.15-rc2-frv-shmem/include/linux/ramfs.h 2005-11-23 16:00:57.000000000 +0000
@@ -5,6 +5,16 @@ struct inode *ramfs_get_inode(struct sup
struct super_block *ramfs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data);
+#ifndef CONFIG_MMU
+extern unsigned long ramfs_nommu_get_unmapped_area(struct file *file,
+ unsigned long addr,
+ unsigned long len,
+ unsigned long pgoff,
+ unsigned long flags);
+
+extern int ramfs_nommu_mmap(struct file *file, struct vm_area_struct *vma);
+#endif
+
extern struct file_operations ramfs_file_operations;
extern struct vm_operations_struct generic_file_vm_ops;
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 3/3] FRV: Implement futex operations for FRV
2005-11-23 18:59 [PATCH 1/3] NOMMU: Provide shared-writable mmap support on ramfs David Howells
@ 2005-11-23 18:59 ` David Howells
2005-11-23 18:59 ` [PATCH 2/3] NOMMU: Make SYSV IPC SHM use ramfs facilities on NOMMU David Howells
2005-11-23 19:09 ` [PATCH 1/3] NOMMU: Provide shared-writable mmap support on ramfs Linus Torvalds
2 siblings, 0 replies; 6+ messages in thread
From: David Howells @ 2005-11-23 18:59 UTC (permalink / raw)
To: torvalds, akpm, dalomar; +Cc: linux-kernel, uclinux-dev
The attached patch implements futex operations for the FRV architecture. The
operations are applicable to both MMU and no-MMU modes; though the EFAULT
handling will be a little bit of wasted space on the latter.
Signed-Off-By: David Howells <dhowells@redhat.com>
---
warthog>diffstat -p1 frv-futexop-2615rc2.diff
arch/frv/kernel/Makefile | 1
arch/frv/kernel/futex.c | 242 +++++++++++++++++++++++++++++++++++++++++++++++
include/asm-frv/futex.h | 42 --------
3 files changed, 244 insertions(+), 41 deletions(-)
diff -uNrp linux-2.6.15-rc2-frv/arch/frv/kernel/futex.c linux-2.6.15-rc2-frv-shmem/arch/frv/kernel/futex.c
--- linux-2.6.15-rc2-frv/arch/frv/kernel/futex.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.15-rc2-frv-shmem/arch/frv/kernel/futex.c 2005-11-23 18:09:40.000000000 +0000
@@ -0,0 +1,242 @@
+/* futex.c: futex operations
+ *
+ * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * 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/futex.h>
+#include <asm/futex.h>
+#include <asm/errno.h>
+#include <asm/uaccess.h>
+
+/*
+ * the various futex operations; MMU fault checking is ignored under no-MMU
+ * conditions
+ */
+static inline int atomic_futex_op_xchg_set(int oparg, int __user *uaddr, int *_oldval)
+{
+ int oldval, ret;
+
+ asm("0: \n"
+ " orcc gr0,gr0,gr0,icc3 \n" /* set ICC3.Z */
+ " ckeq icc3,cc7 \n"
+ "1: ld.p %M0,%1 \n" /* LD.P/ORCR must be atomic */
+ " orcr cc7,cc7,cc3 \n" /* set CC3 to true */
+ "2: cst.p %3,%M0 ,cc3,#1 \n"
+ " corcc gr29,gr29,gr0 ,cc3,#1 \n" /* clear ICC3.Z if store happens */
+ " beq icc3,#0,0b \n"
+ " setlos 0,%2 \n"
+ "3: \n"
+ ".subsection 2 \n"
+ "4: setlos %5,%2 \n"
+ " bra 3b \n"
+ ".previous \n"
+ ".section __ex_table,\"a\" \n"
+ " .balign 8 \n"
+ " .long 1b,4b \n"
+ " .long 2b,4b \n"
+ ".previous"
+ : "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
+ : "3"(oparg), "i"(-EFAULT)
+ : "memory", "cc7", "cc3", "icc3"
+ );
+
+ *_oldval = oldval;
+ return ret;
+}
+
+static inline int atomic_futex_op_xchg_add(int oparg, int __user *uaddr, int *_oldval)
+{
+ int oldval, ret;
+
+ asm("0: \n"
+ " orcc gr0,gr0,gr0,icc3 \n" /* set ICC3.Z */
+ " ckeq icc3,cc7 \n"
+ "1: ld.p %M0,%1 \n" /* LD.P/ORCR must be atomic */
+ " orcr cc7,cc7,cc3 \n" /* set CC3 to true */
+ " add %1,%3,%3 \n"
+ "2: cst.p %3,%M0 ,cc3,#1 \n"
+ " corcc gr29,gr29,gr0 ,cc3,#1 \n" /* clear ICC3.Z if store happens */
+ " beq icc3,#0,0b \n"
+ " setlos 0,%2 \n"
+ "3: \n"
+ ".subsection 2 \n"
+ "4: setlos %5,%2 \n"
+ " bra 3b \n"
+ ".previous \n"
+ ".section __ex_table,\"a\" \n"
+ " .balign 8 \n"
+ " .long 1b,4b \n"
+ " .long 2b,4b \n"
+ ".previous"
+ : "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
+ : "3"(oparg), "i"(-EFAULT)
+ : "memory", "cc7", "cc3", "icc3"
+ );
+
+ *_oldval = oldval;
+ return ret;
+}
+
+static inline int atomic_futex_op_xchg_or(int oparg, int __user *uaddr, int *_oldval)
+{
+ int oldval, ret;
+
+ asm("0: \n"
+ " orcc gr0,gr0,gr0,icc3 \n" /* set ICC3.Z */
+ " ckeq icc3,cc7 \n"
+ "1: ld.p %M0,%1 \n" /* LD.P/ORCR must be atomic */
+ " orcr cc7,cc7,cc3 \n" /* set CC3 to true */
+ " or %1,%3,%3 \n"
+ "2: cst.p %3,%M0 ,cc3,#1 \n"
+ " corcc gr29,gr29,gr0 ,cc3,#1 \n" /* clear ICC3.Z if store happens */
+ " beq icc3,#0,0b \n"
+ " setlos 0,%2 \n"
+ "3: \n"
+ ".subsection 2 \n"
+ "4: setlos %5,%2 \n"
+ " bra 3b \n"
+ ".previous \n"
+ ".section __ex_table,\"a\" \n"
+ " .balign 8 \n"
+ " .long 1b,4b \n"
+ " .long 2b,4b \n"
+ ".previous"
+ : "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
+ : "3"(oparg), "i"(-EFAULT)
+ : "memory", "cc7", "cc3", "icc3"
+ );
+
+ *_oldval = oldval;
+ return ret;
+}
+
+static inline int atomic_futex_op_xchg_and(int oparg, int __user *uaddr, int *_oldval)
+{
+ int oldval, ret;
+
+ asm("0: \n"
+ " orcc gr0,gr0,gr0,icc3 \n" /* set ICC3.Z */
+ " ckeq icc3,cc7 \n"
+ "1: ld.p %M0,%1 \n" /* LD.P/ORCR must be atomic */
+ " orcr cc7,cc7,cc3 \n" /* set CC3 to true */
+ " and %1,%3,%3 \n"
+ "2: cst.p %3,%M0 ,cc3,#1 \n"
+ " corcc gr29,gr29,gr0 ,cc3,#1 \n" /* clear ICC3.Z if store happens */
+ " beq icc3,#0,0b \n"
+ " setlos 0,%2 \n"
+ "3: \n"
+ ".subsection 2 \n"
+ "4: setlos %5,%2 \n"
+ " bra 3b \n"
+ ".previous \n"
+ ".section __ex_table,\"a\" \n"
+ " .balign 8 \n"
+ " .long 1b,4b \n"
+ " .long 2b,4b \n"
+ ".previous"
+ : "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
+ : "3"(oparg), "i"(-EFAULT)
+ : "memory", "cc7", "cc3", "icc3"
+ );
+
+ *_oldval = oldval;
+ return ret;
+}
+
+static inline int atomic_futex_op_xchg_xor(int oparg, int __user *uaddr, int *_oldval)
+{
+ int oldval, ret;
+
+ asm("0: \n"
+ " orcc gr0,gr0,gr0,icc3 \n" /* set ICC3.Z */
+ " ckeq icc3,cc7 \n"
+ "1: ld.p %M0,%1 \n" /* LD.P/ORCR must be atomic */
+ " orcr cc7,cc7,cc3 \n" /* set CC3 to true */
+ " xor %1,%3,%3 \n"
+ "2: cst.p %3,%M0 ,cc3,#1 \n"
+ " corcc gr29,gr29,gr0 ,cc3,#1 \n" /* clear ICC3.Z if store happens */
+ " beq icc3,#0,0b \n"
+ " setlos 0,%2 \n"
+ "3: \n"
+ ".subsection 2 \n"
+ "4: setlos %5,%2 \n"
+ " bra 3b \n"
+ ".previous \n"
+ ".section __ex_table,\"a\" \n"
+ " .balign 8 \n"
+ " .long 1b,4b \n"
+ " .long 2b,4b \n"
+ ".previous"
+ : "+U"(*uaddr), "=&r"(oldval), "=&r"(ret), "=r"(oparg)
+ : "3"(oparg), "i"(-EFAULT)
+ : "memory", "cc7", "cc3", "icc3"
+ );
+
+ *_oldval = oldval;
+ return ret;
+}
+
+/*****************************************************************************/
+/*
+ * do the futex operations
+ */
+int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
+{
+ int op = (encoded_op >> 28) & 7;
+ int cmp = (encoded_op >> 24) & 15;
+ int oparg = (encoded_op << 8) >> 20;
+ int cmparg = (encoded_op << 20) >> 20;
+ int oldval = 0, ret;
+
+ if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
+ oparg = 1 << oparg;
+
+ if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
+ return -EFAULT;
+
+ inc_preempt_count();
+
+ switch (op) {
+ case FUTEX_OP_SET:
+ ret = atomic_futex_op_xchg_set(oparg, uaddr, &oldval);
+ break;
+ case FUTEX_OP_ADD:
+ ret = atomic_futex_op_xchg_add(oparg, uaddr, &oldval);
+ break;
+ case FUTEX_OP_OR:
+ ret = atomic_futex_op_xchg_or(oparg, uaddr, &oldval);
+ break;
+ case FUTEX_OP_ANDN:
+ ret = atomic_futex_op_xchg_and(~oparg, uaddr, &oldval);
+ break;
+ case FUTEX_OP_XOR:
+ ret = atomic_futex_op_xchg_xor(oparg, uaddr, &oldval);
+ break;
+ default:
+ ret = -ENOSYS;
+ break;
+ }
+
+ dec_preempt_count();
+
+ if (!ret) {
+ switch (cmp) {
+ case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
+ case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
+ case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
+ case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
+ case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
+ case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
+ default: ret = -ENOSYS; break;
+ }
+ }
+
+ return ret;
+
+} /* end futex_atomic_op_inuser() */
diff -uNrp linux-2.6.15-rc2-frv/arch/frv/kernel/Makefile linux-2.6.15-rc2-frv-shmem/arch/frv/kernel/Makefile
--- linux-2.6.15-rc2-frv/arch/frv/kernel/Makefile 2005-03-02 12:07:44.000000000 +0000
+++ linux-2.6.15-rc2-frv-shmem/arch/frv/kernel/Makefile 2005-11-23 18:10:10.000000000 +0000
@@ -20,3 +20,4 @@ obj-$(CONFIG_FUJITSU_MB93493) += irq-mb9
obj-$(CONFIG_PM) += pm.o cmode.o
obj-$(CONFIG_MB93093_PDK) += pm-mb93093.o
obj-$(CONFIG_SYSCTL) += sysctl.o
+obj-$(CONFIG_FUTEX) += futex.o
diff -uNrp linux-2.6.15-rc2-frv/include/asm-frv/futex.h linux-2.6.15-rc2-frv-shmem/include/asm-frv/futex.h
--- linux-2.6.15-rc2-frv/include/asm-frv/futex.h 2005-11-01 13:19:17.000000000 +0000
+++ linux-2.6.15-rc2-frv-shmem/include/asm-frv/futex.h 2005-11-23 17:58:48.000000000 +0000
@@ -7,47 +7,7 @@
#include <asm/errno.h>
#include <asm/uaccess.h>
-static inline int
-futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
-{
- int op = (encoded_op >> 28) & 7;
- int cmp = (encoded_op >> 24) & 15;
- int oparg = (encoded_op << 8) >> 20;
- int cmparg = (encoded_op << 20) >> 20;
- int oldval = 0, ret;
- if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
- oparg = 1 << oparg;
-
- if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
- return -EFAULT;
-
- inc_preempt_count();
-
- switch (op) {
- case FUTEX_OP_SET:
- case FUTEX_OP_ADD:
- case FUTEX_OP_OR:
- case FUTEX_OP_ANDN:
- case FUTEX_OP_XOR:
- default:
- ret = -ENOSYS;
- }
-
- dec_preempt_count();
-
- if (!ret) {
- switch (cmp) {
- case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
- case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
- case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
- case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
- case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
- case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
- default: ret = -ENOSYS;
- }
- }
- return ret;
-}
+extern int futex_atomic_op_inuser(int encoded_op, int __user *uaddr);
#endif
#endif
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 2/3] NOMMU: Make SYSV IPC SHM use ramfs facilities on NOMMU
2005-11-23 18:59 [PATCH 1/3] NOMMU: Provide shared-writable mmap support on ramfs David Howells
2005-11-23 18:59 ` [PATCH 3/3] FRV: Implement futex operations for FRV David Howells
@ 2005-11-23 18:59 ` David Howells
2005-11-23 19:09 ` [PATCH 1/3] NOMMU: Provide shared-writable mmap support on ramfs Linus Torvalds
2 siblings, 0 replies; 6+ messages in thread
From: David Howells @ 2005-11-23 18:59 UTC (permalink / raw)
To: torvalds, akpm, dalomar; +Cc: linux-kernel, uclinux-dev
The attached patch makes the SYSV IPC shared memory facilities use the new
ramfs facilities on a no-MMU kernel.
The following changes are made:
(1) There are now shmem_mmap() and shmem_get_unmapped_area() functions to
allow the IPC SHM facilities to commune with the tiny-shmem and shmem
code.
(2) ramfs files now need resizing using do_truncate() rather than by modifying
the inode size directly (see shmem_file_setup()). This causes ramfs to
attempt to bind a block of pages of sufficient size to the inode.
(3) CONFIG_SYSVIPC is no longer contingent on CONFIG_MMU.
Signed-Off-By: David Howells <dhowells@redhat.com>
---
warthog>diffstat -p1 shmem-nommu-2615rc2.diff
include/linux/mm.h | 9 +++++++++
init/Kconfig | 1 -
ipc/shm.c | 18 +++++++++++++-----
mm/nommu.c | 6 ++++++
mm/shmem.c | 2 +-
mm/tiny-shmem.c | 29 ++++++++++++++++++++++++++++-
6 files changed, 57 insertions(+), 8 deletions(-)
diff -uNrp linux-2.6.15-rc2-frv/include/linux/mm.h linux-2.6.15-rc2-frv-shmem/include/linux/mm.h
--- linux-2.6.15-rc2-frv/include/linux/mm.h 2005-11-23 13:29:08.000000000 +0000
+++ linux-2.6.15-rc2-frv-shmem/include/linux/mm.h 2005-11-23 16:46:59.000000000 +0000
@@ -656,9 +656,18 @@ int shmem_lock(struct file *file, int lo
#define shmem_get_policy(a, b) (NULL)
#endif
struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags);
+extern int shmem_mmap(struct file *file, struct vm_area_struct *vma);
int shmem_zero_setup(struct vm_area_struct *);
+#ifndef CONFIG_MMU
+extern unsigned long shmem_get_unmapped_area(struct file *file,
+ unsigned long addr,
+ unsigned long len,
+ unsigned long pgoff,
+ unsigned long flags);
+#endif
+
static inline int can_do_mlock(void)
{
if (capable(CAP_IPC_LOCK))
diff -uNrp linux-2.6.15-rc2-frv/init/Kconfig linux-2.6.15-rc2-frv-shmem/init/Kconfig
--- linux-2.6.15-rc2-frv/init/Kconfig 2005-11-23 12:09:23.000000000 +0000
+++ linux-2.6.15-rc2-frv-shmem/init/Kconfig 2005-11-23 16:00:57.000000000 +0000
@@ -105,7 +105,6 @@ config SWAP
config SYSVIPC
bool "System V IPC"
- depends on MMU
---help---
Inter Process Communication is a suite of library functions and
system calls which let processes (running programs) synchronize and
diff -uNrp linux-2.6.15-rc2-frv/ipc/shm.c linux-2.6.15-rc2-frv-shmem/ipc/shm.c
--- linux-2.6.15-rc2-frv/ipc/shm.c 2005-11-23 12:09:23.000000000 +0000
+++ linux-2.6.15-rc2-frv-shmem/ipc/shm.c 2005-11-23 16:45:44.000000000 +0000
@@ -157,14 +157,22 @@ static void shm_close (struct vm_area_st
static int shm_mmap(struct file * file, struct vm_area_struct * vma)
{
- file_accessed(file);
- vma->vm_ops = &shm_vm_ops;
- shm_inc(file->f_dentry->d_inode->i_ino);
- return 0;
+ int ret;
+
+ ret = shmem_mmap(file, vma);
+ if (ret == 0) {
+ vma->vm_ops = &shm_vm_ops;
+ shm_inc(file->f_dentry->d_inode->i_ino);
+ }
+
+ return ret;
}
static struct file_operations shm_file_operations = {
- .mmap = shm_mmap
+ .mmap = shm_mmap,
+#ifndef CONFIG_MMU
+ .get_unmapped_area = shmem_get_unmapped_area,
+#endif
};
static struct vm_operations_struct shm_vm_ops = {
diff -uNrp linux-2.6.15-rc2-frv/mm/nommu.c linux-2.6.15-rc2-frv-shmem/mm/nommu.c
--- linux-2.6.15-rc2-frv/mm/nommu.c 2005-11-23 12:09:24.000000000 +0000
+++ linux-2.6.15-rc2-frv-shmem/mm/nommu.c 2005-11-23 16:00:57.000000000 +0000
@@ -1177,3 +1177,9 @@ int in_gate_area_no_task(unsigned long a
{
return 0;
}
+
+struct page * filemap_nopage(struct vm_area_struct * area, unsigned long address, int *type)
+{
+ BUG();
+ return NULL;
+}
diff -uNrp linux-2.6.15-rc2-frv/mm/shmem.c linux-2.6.15-rc2-frv-shmem/mm/shmem.c
--- linux-2.6.15-rc2-frv/mm/shmem.c 2005-11-23 12:09:24.000000000 +0000
+++ linux-2.6.15-rc2-frv-shmem/mm/shmem.c 2005-11-23 16:00:57.000000000 +0000
@@ -1255,7 +1255,7 @@ out_nomem:
return retval;
}
-static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
+int shmem_mmap(struct file *file, struct vm_area_struct *vma)
{
file_accessed(file);
vma->vm_ops = &shmem_vm_ops;
diff -uNrp linux-2.6.15-rc2-frv/mm/tiny-shmem.c linux-2.6.15-rc2-frv-shmem/mm/tiny-shmem.c
--- linux-2.6.15-rc2-frv/mm/tiny-shmem.c 2005-11-23 12:09:24.000000000 +0000
+++ linux-2.6.15-rc2-frv-shmem/mm/tiny-shmem.c 2005-11-23 16:46:15.000000000 +0000
@@ -81,13 +81,19 @@ struct file *shmem_file_setup(char *name
goto close_file;
d_instantiate(dentry, inode);
- inode->i_size = size;
inode->i_nlink = 0; /* It is unlinked */
+
file->f_vfsmnt = mntget(shm_mnt);
file->f_dentry = dentry;
file->f_mapping = inode->i_mapping;
file->f_op = &ramfs_file_operations;
file->f_mode = FMODE_WRITE | FMODE_READ;
+
+ /* notify everyone as to the change of file size */
+ error = do_truncate(dentry, size, file);
+ if (error < 0)
+ goto close_file;
+
return file;
close_file:
@@ -123,3 +129,24 @@ int shmem_unuse(swp_entry_t entry, struc
{
return 0;
}
+
+int shmem_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ file_accessed(file);
+#ifndef CONFIG_MMU
+ return ramfs_nommu_mmap(file, vma);
+#else
+ return 0;
+#endif
+}
+
+#ifndef CONFIG_MMU
+unsigned long shmem_get_unmapped_area(struct file *file,
+ unsigned long addr,
+ unsigned long len,
+ unsigned long pgoff,
+ unsigned long flags)
+{
+ return ramfs_nommu_get_unmapped_area(file, addr, len, pgoff, flags);
+}
+#endif
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/3] NOMMU: Provide shared-writable mmap support on ramfs
2005-11-23 18:59 [PATCH 1/3] NOMMU: Provide shared-writable mmap support on ramfs David Howells
2005-11-23 18:59 ` [PATCH 3/3] FRV: Implement futex operations for FRV David Howells
2005-11-23 18:59 ` [PATCH 2/3] NOMMU: Make SYSV IPC SHM use ramfs facilities on NOMMU David Howells
@ 2005-11-23 19:09 ` Linus Torvalds
2005-11-23 19:23 ` David Howells
2 siblings, 1 reply; 6+ messages in thread
From: Linus Torvalds @ 2005-11-23 19:09 UTC (permalink / raw)
To: David Howells; +Cc: akpm, dalomar, linux-kernel, uclinux-dev
On Wed, 23 Nov 2005, David Howells wrote:
>
> (3) Not permitting a file to be shrunk if it would truncate any shared
> mappings (private mappings are copied).
Why?
Truncate is _supposed_ to get rid of any shared mmap stuff.
Linus
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/3] NOMMU: Provide shared-writable mmap support on ramfs
2005-11-23 19:09 ` [PATCH 1/3] NOMMU: Provide shared-writable mmap support on ramfs Linus Torvalds
@ 2005-11-23 19:23 ` David Howells
2005-11-23 19:25 ` David Howells
0 siblings, 1 reply; 6+ messages in thread
From: David Howells @ 2005-11-23 19:23 UTC (permalink / raw)
To: Linus Torvalds; +Cc: David Howells, akpm, dalomar, linux-kernel, uclinux-dev
Linus Torvalds <torvalds@osdl.org> wrote:
> > (3) Not permitting a file to be shrunk if it would truncate any shared
> > mappings (private mappings are copied).
>
> Why?
>
> Truncate is _supposed_ to get rid of any shared mmap stuff.
Yeah... but under _NOMMU_ conditions, it can't. There's no MMU around to
enforce the fact that the mapping has been shrunk.
Imagine two processes: one creates a shmem file and makes it a certain size;
both processes mmap it; then one of the processes attempts to shrink it. The
process that shrank it knows it has been shortened and that the memory has
been release, but the second process may not. Splat.
David
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/3] NOMMU: Provide shared-writable mmap support on ramfs
2005-11-23 19:23 ` David Howells
@ 2005-11-23 19:25 ` David Howells
0 siblings, 0 replies; 6+ messages in thread
From: David Howells @ 2005-11-23 19:25 UTC (permalink / raw)
To: David Howells; +Cc: Linus Torvalds, akpm, dalomar, linux-kernel, uclinux-dev
David Howells <dhowells@redhat.com> wrote:
> > Truncate is _supposed_ to get rid of any shared mmap stuff.
>
> Yeah... but under _NOMMU_ conditions, it can't. There's no MMU around to
> enforce the fact that the mapping has been shrunk.
I may not have mentioned, but this does not apply under MMU conditions. A
different file in fs/ramfs/ swings into action and does the normal thing.
David
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2005-11-23 19:25 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2005-11-23 18:59 [PATCH 1/3] NOMMU: Provide shared-writable mmap support on ramfs David Howells
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2005-11-23 18:59 ` [PATCH 2/3] NOMMU: Make SYSV IPC SHM use ramfs facilities on NOMMU David Howells
2005-11-23 19:09 ` [PATCH 1/3] NOMMU: Provide shared-writable mmap support on ramfs Linus Torvalds
2005-11-23 19:23 ` David Howells
2005-11-23 19:25 ` David Howells
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