From: Ingo Molnar <mingo@elte.hu>
- enable the 'prot' parameter for shared-writable mappings (the ones
which are the primary target for fremap), without breaking up the
vma.
- added MAP_INHERIT: this both cleanly implements the old
sys_remap_file_pages() semantics, and might be useful as well.
it adds a new syscall because the old sys_remap_file_pages() syscall was
messed up in an unfixable way :-( [prot == 0 means PROT_NONE and now we
need this.] But the patch is ABI-compatible, it keeps the old syscall
and wraps it cleanly internally.
patch applies, compiles & boots cleanly on SMP x86 and ppc, it compiles
cleanly on x86_64. Other architectures wont compile, they need to do this:
- add MAP_INHERIT
- add pte_to_pgprot()
- pgoff_to_pte() is replaced by pgoff_prot_to_pte()
- chop a bit off __swp_type() if there's no more space.
- add the new sys_remap_file_pages() syscall slot
- rename the old sys_remap_file_pages() syscall slot to old_remap_file_pages()
it should be quite straightforward for them, but needs to be tested.
other changes:
- generate SIGSEGV on PROT_NONE mappings - instead of an infinite
pagefault loop. Note to non-x86 arch maintainers: do_page_fault()
now needs to handle a VM_FAULT_SIGSEGV return value from
handle_pte_fault(), and the pte_to_pgprot() macro has to be added.
- fixed the 'else' branch in both filemap_populate and shmem_populate.
We cannot just skip setting the file-pte if the new mapping is linear
- a nonlinear entry can be linear just by chance as well. So we must
overwrite the pte in every case. I've pushed one linear/nonlinear
optimization into install_file_pte: if the pte is empty _and_ the
mapping is linear then we can leave the pte alone.
- fixed MAP_POPULATE: since 'prot' is nonzero in all the interesting
do_mmap() situations, the old version of sys_remap_file_pages() just
punted on it.
- minor detail: filemap_getpage(nonblock) case now returns NULL if a
page is present but not uptodate. (because in the !uptodate case we
start a wait which is contrary to nonblock.)
---
25-akpm/arch/i386/kernel/entry.S | 3
25-akpm/arch/i386/mm/fault.c | 2
25-akpm/arch/x86_64/ia32/ia32entry.S | 2
25-akpm/include/asm-i386/mman.h | 1
25-akpm/include/asm-i386/pgtable-2level.h | 15 ++-
25-akpm/include/asm-i386/pgtable-3level.h | 11 ++
25-akpm/include/asm-i386/unistd.h | 5 -
25-akpm/include/asm-ppc/mman.h | 1
25-akpm/include/asm-ppc/pgtable.h | 15 ++-
25-akpm/include/asm-x86_64/ia32_unistd.h | 2
25-akpm/include/asm-x86_64/mman.h | 1
25-akpm/include/asm-x86_64/pgtable.h | 12 ++
25-akpm/include/asm-x86_64/unistd.h | 4
25-akpm/include/linux/mm.h | 12 +-
25-akpm/include/linux/syscalls.h | 5 -
25-akpm/mm/filemap.c | 34 ++++---
25-akpm/mm/fremap.c | 135 ++++++++++++++++++++----------
25-akpm/mm/memory.c | 13 ++
25-akpm/mm/mmap.c | 8 +
25-akpm/mm/rmap.c | 7 +
25-akpm/mm/shmem.c | 19 +---
21 files changed, 210 insertions(+), 97 deletions(-)
diff -puN arch/i386/kernel/entry.S~remap-file-pages-prot-2.6.4-rc1-mm1-A1 arch/i386/kernel/entry.S
--- 25/arch/i386/kernel/entry.S~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.503976464 -0800
+++ 25-akpm/arch/i386/kernel/entry.S 2004-03-30 20:44:54.534971752 -0800
@@ -891,7 +891,7 @@ ENTRY(sys_call_table)
.long sys_epoll_create
.long sys_epoll_ctl /* 255 */
.long sys_epoll_wait
- .long sys_remap_file_pages
+ .long old_remap_file_pages
.long sys_set_tid_address
.long sys_timer_create
.long sys_timer_settime /* 260 */
@@ -914,5 +914,6 @@ ENTRY(sys_call_table)
.long sys_mq_timedreceive
.long sys_mq_notify
.long sys_mq_getsetattr
+ .long sys_remap_file_pages /* 280 */
syscall_table_size=(.-sys_call_table)
diff -puN arch/i386/mm/fault.c~remap-file-pages-prot-2.6.4-rc1-mm1-A1 arch/i386/mm/fault.c
--- 25/arch/i386/mm/fault.c~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.505976160 -0800
+++ 25-akpm/arch/i386/mm/fault.c 2004-03-30 20:44:54.534971752 -0800
@@ -326,6 +326,8 @@ good_area:
goto do_sigbus;
case VM_FAULT_OOM:
goto out_of_memory;
+ case VM_FAULT_SIGSEGV:
+ goto bad_area;
default:
BUG();
}
diff -puN arch/x86_64/ia32/ia32entry.S~remap-file-pages-prot-2.6.4-rc1-mm1-A1 arch/x86_64/ia32/ia32entry.S
--- 25/arch/x86_64/ia32/ia32entry.S~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.507975856 -0800
+++ 25-akpm/arch/x86_64/ia32/ia32entry.S 2004-03-30 20:44:54.535971600 -0800
@@ -562,7 +562,7 @@ ia32_sys_call_table:
.quad sys_epoll_create
.quad sys_epoll_ctl
.quad sys_epoll_wait
- .quad sys_remap_file_pages
+ .quad old_remap_file_pages
.quad sys_set_tid_address
.quad sys32_timer_create
.quad compat_timer_settime
diff -puN include/asm-i386/mman.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 include/asm-i386/mman.h
--- 25/include/asm-i386/mman.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.508975704 -0800
+++ 25-akpm/include/asm-i386/mman.h 2004-03-30 20:44:54.535971600 -0800
@@ -22,6 +22,7 @@
#define MAP_NORESERVE 0x4000 /* don't check for reservations */
#define MAP_POPULATE 0x8000 /* populate (prefault) pagetables */
#define MAP_NONBLOCK 0x10000 /* do not block on IO */
+#define MAP_INHERIT 0x20000 /* inherit the protection bits of the underlying vma*/
#define MS_ASYNC 1 /* sync memory asynchronously */
#define MS_INVALIDATE 2 /* invalidate the caches */
diff -puN include/asm-i386/pgtable-2level.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 include/asm-i386/pgtable-2level.h
--- 25/include/asm-i386/pgtable-2level.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.509975552 -0800
+++ 25-akpm/include/asm-i386/pgtable-2level.h 2004-03-30 20:44:54.536971448 -0800
@@ -64,15 +64,20 @@ static inline pmd_t * pmd_offset(pgd_t *
#define pfn_pmd(pfn, prot) __pmd(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
/*
- * Bits 0, 6 and 7 are taken, split up the 29 bits of offset
+ * Bits 0, 1, 6 and 7 are taken, split up the 28 bits of offset
* into this range:
*/
-#define PTE_FILE_MAX_BITS 29
+#define PTE_FILE_MAX_BITS 28
#define pte_to_pgoff(pte) \
- ((((pte).pte_low >> 1) & 0x1f ) + (((pte).pte_low >> 8) << 5 ))
+ ((((pte).pte_low >> 2) & 0xf ) + (((pte).pte_low >> 8) << 4 ))
+#define pte_to_pgprot(pte) \
+ __pgprot(((pte).pte_low & (_PAGE_RW | _PAGE_PROTNONE)) \
+ | (((pte).pte_low & _PAGE_PROTNONE) ? 0 : \
+ (_PAGE_USER | _PAGE_PRESENT)) | _PAGE_ACCESSED)
-#define pgoff_to_pte(off) \
- ((pte_t) { (((off) & 0x1f) << 1) + (((off) >> 5) << 8) + _PAGE_FILE })
+#define pgoff_prot_to_pte(off, prot) \
+ ((pte_t) { (((off) & 0xf) << 2) + (((off) >> 4) << 8) + \
+ (pgprot_val(prot) & (_PAGE_RW | _PAGE_PROTNONE)) + _PAGE_FILE })
#endif /* _I386_PGTABLE_2LEVEL_H */
diff -puN include/asm-i386/pgtable-3level.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 include/asm-i386/pgtable-3level.h
--- 25/include/asm-i386/pgtable-3level.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.510975400 -0800
+++ 25-akpm/include/asm-i386/pgtable-3level.h 2004-03-30 20:44:54.536971448 -0800
@@ -120,7 +120,16 @@ static inline pmd_t pfn_pmd(unsigned lon
* put the 32 bits of offset into the high part.
*/
#define pte_to_pgoff(pte) ((pte).pte_high)
-#define pgoff_to_pte(off) ((pte_t) { _PAGE_FILE, (off) })
+
+#define pte_to_pgprot(pte) \
+ __pgprot(((pte).pte_low & (_PAGE_RW | _PAGE_PROTNONE)) \
+ | (((pte).pte_low & _PAGE_PROTNONE) ? 0 : \
+ (_PAGE_USER | _PAGE_PRESENT)) | _PAGE_ACCESSED)
+
+#define pgoff_prot_to_pte(off, prot) \
+ ((pte_t) { _PAGE_FILE + \
+ (pgprot_val(prot) & (_PAGE_RW | _PAGE_PROTNONE)) , (off) })
+
#define PTE_FILE_MAX_BITS 32
extern struct kmem_cache_s *pae_pgd_cachep;
diff -puN include/asm-i386/unistd.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 include/asm-i386/unistd.h
--- 25/include/asm-i386/unistd.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.512975096 -0800
+++ 25-akpm/include/asm-i386/unistd.h 2004-03-30 20:44:54.537971296 -0800
@@ -262,7 +262,7 @@
#define __NR_epoll_create 254
#define __NR_epoll_ctl 255
#define __NR_epoll_wait 256
-#define __NR_remap_file_pages 257
+#define __NR_old_remap_file_pages 257
#define __NR_set_tid_address 258
#define __NR_timer_create 259
#define __NR_timer_settime (__NR_timer_create+1)
@@ -285,8 +285,9 @@
#define __NR_mq_timedreceive (__NR_mq_open+3)
#define __NR_mq_notify (__NR_mq_open+4)
#define __NR_mq_getsetattr (__NR_mq_open+5)
+#define __NR_remap_file_pages 280
-#define NR_syscalls 280
+#define NR_syscalls 281
/* user-visible error numbers are in the range -1 - -124: see <asm-i386/errno.h> */
diff -puN include/asm-ppc/mman.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 include/asm-ppc/mman.h
--- 25/include/asm-ppc/mman.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.513974944 -0800
+++ 25-akpm/include/asm-ppc/mman.h 2004-03-30 20:44:54.537971296 -0800
@@ -23,6 +23,7 @@
#define MAP_EXECUTABLE 0x1000 /* mark it as an executable */
#define MAP_POPULATE 0x8000 /* populate (prefault) pagetables */
#define MAP_NONBLOCK 0x10000 /* do not block on IO */
+#define MAP_INHERIT 0x20000 /* inherit prot of underlying vma */
#define MS_ASYNC 1 /* sync memory asynchronously */
#define MS_INVALIDATE 2 /* invalidate the caches */
diff -puN include/asm-ppc/pgtable.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 include/asm-ppc/pgtable.h
--- 25/include/asm-ppc/pgtable.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.514974792 -0800
+++ 25-akpm/include/asm-ppc/pgtable.h 2004-03-30 20:44:54.538971144 -0800
@@ -264,8 +264,8 @@ extern unsigned long ioremap_bot, iorema
/* Definitions for 60x, 740/750, etc. */
#define _PAGE_PRESENT 0x001 /* software: pte contains a translation */
#define _PAGE_HASHPTE 0x002 /* hash_page has made an HPTE for this pte */
-#define _PAGE_FILE 0x004 /* when !present: nonlinear file mapping */
#define _PAGE_USER 0x004 /* usermode access allowed */
+#define _PAGE_FILE 0x008 /* when !present: nonlinear file mapping */
#define _PAGE_GUARDED 0x008 /* G: prohibit speculative access */
#define _PAGE_COHERENT 0x010 /* M: enforce memory coherence (SMP systems) */
#define _PAGE_NO_CACHE 0x020 /* I: cache inhibit */
@@ -628,9 +628,16 @@ extern void add_hash_page(unsigned conte
#define __swp_entry_to_pte(x) ((pte_t) { (x).val << 3 })
/* Encode and decode a nonlinear file mapping entry */
-#define PTE_FILE_MAX_BITS 29
-#define pte_to_pgoff(pte) (pte_val(pte) >> 3)
-#define pgoff_to_pte(off) ((pte_t) { ((off) << 3) | _PAGE_FILE })
+#define PTE_FILE_MAX_BITS 27
+#define pte_to_pgoff(pte) (((pte_val(pte) & ~0x7ff) >> 5) \
+ | ((pte_val(pte) & 0x3f0) >> 4))
+#define pte_to_pgprot(pte) \
+__pgprot((pte_val(pte) & (_PAGE_USER|_PAGE_RW|_PAGE_PRESENT)) | _PAGE_ACCESSED)
+
+#define pgoff_prot_to_pte(off, prot) \
+ ((pte_t) { (((off) << 5) & ~0x7ff) | (((off) << 4) & 0x3f0) \
+ | (pgprot_val(prot) & (_PAGE_USER|_PAGE_RW)) \
+ | _PAGE_FILE })
/* CONFIG_APUS */
/* For virtual address to physical address conversion */
diff -puN include/asm-x86_64/ia32_unistd.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 include/asm-x86_64/ia32_unistd.h
--- 25/include/asm-x86_64/ia32_unistd.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.516974488 -0800
+++ 25-akpm/include/asm-x86_64/ia32_unistd.h 2004-03-30 20:44:54.538971144 -0800
@@ -262,7 +262,7 @@
#define __NR_ia32_sys_epoll_create 254
#define __NR_ia32_sys_epoll_ctl 255
#define __NR_ia32_sys_epoll_wait 256
-#define __NR_ia32_remap_file_pages 257
+#define __NR_ia32_old_remap_file_pages 257
#define __NR_ia32_set_tid_address 258
#define __NR_ia32_timer_create 259
#define __NR_ia32_timer_settime (__NR_ia32_timer_create+1)
diff -puN include/asm-x86_64/mman.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 include/asm-x86_64/mman.h
--- 25/include/asm-x86_64/mman.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.517974336 -0800
+++ 25-akpm/include/asm-x86_64/mman.h 2004-03-30 20:44:54.539970992 -0800
@@ -23,6 +23,7 @@
#define MAP_NORESERVE 0x4000 /* don't check for reservations */
#define MAP_POPULATE 0x8000 /* populate (prefault) pagetables */
#define MAP_NONBLOCK 0x10000 /* do not block on IO */
+#define MAP_INHERIT 0x20000 /* inherit the protection bits of the underlying vma*/
#define MS_ASYNC 1 /* sync memory asynchronously */
#define MS_INVALIDATE 2 /* invalidate the caches */
diff -puN include/asm-x86_64/pgtable.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 include/asm-x86_64/pgtable.h
--- 25/include/asm-x86_64/pgtable.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.518974184 -0800
+++ 25-akpm/include/asm-x86_64/pgtable.h 2004-03-30 20:44:54.539970992 -0800
@@ -344,9 +344,19 @@ static inline pgd_t *current_pgd_offset_
#define pmd_pfn(x) ((pmd_val(x) >> PAGE_SHIFT) & __PHYSICAL_MASK)
#define pte_to_pgoff(pte) ((pte_val(pte) & PHYSICAL_PAGE_MASK) >> PAGE_SHIFT)
-#define pgoff_to_pte(off) ((pte_t) { ((off) << PAGE_SHIFT) | _PAGE_FILE })
#define PTE_FILE_MAX_BITS __PHYSICAL_MASK_SHIFT
+#define pte_to_pgprot(pte) \
+ __pgprot((pte_val(pte) & (_PAGE_RW | _PAGE_PROTNONE)) \
+ | ((pte_val(pte) & _PAGE_PROTNONE) ? 0 : \
+ (_PAGE_USER | _PAGE_PRESENT)) | _PAGE_ACCESSED)
+
+#define pgoff_prot_to_pte(off, prot) \
+ ((pte_t) { _PAGE_FILE + \
+ (pgprot_val(prot) & (_PAGE_RW | _PAGE_PROTNONE)) + \
+ ((off) << PAGE_SHIFT) })
+
+
/* PTE - Level 1 access. */
/* page, protection -> pte */
diff -puN include/asm-x86_64/unistd.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 include/asm-x86_64/unistd.h
--- 25/include/asm-x86_64/unistd.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.520973880 -0800
+++ 25-akpm/include/asm-x86_64/unistd.h 2004-03-30 20:44:54.540970840 -0800
@@ -490,8 +490,8 @@ __SYSCALL(__NR_epoll_create, sys_epoll_c
__SYSCALL(__NR_epoll_ctl_old, sys_ni_syscall)
#define __NR_epoll_wait_old 215
__SYSCALL(__NR_epoll_wait_old, sys_ni_syscall)
-#define __NR_remap_file_pages 216
-__SYSCALL(__NR_remap_file_pages, sys_remap_file_pages)
+#define __NR_old_remap_file_pages 216
+__SYSCALL(__NR_old_remap_file_pages, old_remap_file_pages)
#define __NR_getdents64 217
__SYSCALL(__NR_getdents64, sys_getdents64)
#define __NR_set_tid_address 218
diff -puN include/linux/mm.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 include/linux/mm.h
--- 25/include/linux/mm.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.521973728 -0800
+++ 25-akpm/include/linux/mm.h 2004-03-30 20:44:54.541970688 -0800
@@ -423,10 +423,11 @@ static inline int page_mapped(struct pag
* Used to decide whether a process gets delivered SIGBUS or
* just gets major/minor fault counters bumped up.
*/
-#define VM_FAULT_OOM (-1)
-#define VM_FAULT_SIGBUS 0
-#define VM_FAULT_MINOR 1
-#define VM_FAULT_MAJOR 2
+#define VM_FAULT_OOM (-1)
+#define VM_FAULT_SIGBUS 0
+#define VM_FAULT_MINOR 1
+#define VM_FAULT_MAJOR 2
+#define VM_FAULT_SIGSEGV 3
#define offset_in_page(p) ((unsigned long)(p) & ~PAGE_MASK)
@@ -459,9 +460,10 @@ extern pmd_t *FASTCALL(__pmd_alloc(struc
extern pte_t *FASTCALL(pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsigned long address));
extern pte_t *FASTCALL(pte_alloc_map(struct mm_struct *mm, pmd_t *pmd, unsigned long address));
extern int install_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, struct page *page, pgprot_t prot);
-extern int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, unsigned long pgoff, pgprot_t prot);
+extern int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, unsigned long pgoff, pgprot_t prot, int linear);
extern int handle_mm_fault(struct mm_struct *mm,struct vm_area_struct *vma, unsigned long address, int write_access);
extern int make_pages_present(unsigned long addr, unsigned long end);
+extern long __remap_file_pages(struct mm_struct *mm, unsigned long start, unsigned long size, unsigned long prot, unsigned long pgoff, unsigned long flags);
extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
void put_dirty_page(struct task_struct *tsk, struct page *page,
unsigned long address, pgprot_t prot);
diff -puN include/linux/syscalls.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 include/linux/syscalls.h
--- 25/include/linux/syscalls.h~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.523973424 -0800
+++ 25-akpm/include/linux/syscalls.h 2004-03-30 20:44:54.542970536 -0800
@@ -254,7 +254,10 @@ asmlinkage long sys_mprotect(unsigned lo
asmlinkage unsigned long sys_mremap(unsigned long addr,
unsigned long old_len, unsigned long new_len,
unsigned long flags, unsigned long new_addr);
-long sys_remap_file_pages(unsigned long start, unsigned long size,
+asmlinkage long old_remap_file_pages(unsigned long start, unsigned long size,
+ unsigned long __prot, unsigned long pgoff,
+ unsigned long flags);
+asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size,
unsigned long prot, unsigned long pgoff,
unsigned long flags);
asmlinkage long sys_msync(unsigned long start, size_t len, int flags);
diff -puN mm/filemap.c~remap-file-pages-prot-2.6.4-rc1-mm1-A1 mm/filemap.c
--- 25/mm/filemap.c~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.524973272 -0800
+++ 25-akpm/mm/filemap.c 2004-03-30 20:44:54.544970232 -0800
@@ -39,6 +39,7 @@
#include <asm/uaccess.h>
#include <asm/mman.h>
+#include <asm/tlbflush.h>
/*
* Shared mappings implemented 30.11.1994. It's not fully working yet,
@@ -1237,8 +1238,13 @@ retry_find:
* Ok, found a page in the page cache, now we need to check
* that it's up-to-date.
*/
- if (!PageUptodate(page))
+ if (!PageUptodate(page)) {
+ if (nonblock) {
+ page_cache_release(page);
+ return NULL;
+ }
goto page_not_uptodate;
+ }
success:
/*
@@ -1331,12 +1337,22 @@ static int filemap_populate(struct vm_ar
{
struct file *file = vma->vm_file;
struct address_space *mapping = file->f_mapping;
+ int linear = !(vma->vm_flags & VM_NONLINEAR);
struct inode *inode = mapping->host;
unsigned long size;
struct mm_struct *mm = vma->vm_mm;
struct page *page;
int err;
+ /*
+ * mapping-removal fastpath:
+ */
+ if ((vma->vm_flags & VM_SHARED) &&
+ (pgprot_val(prot) == pgprot_val(PAGE_NONE))) {
+ zap_page_range(vma, addr, len);
+ return 0;
+ }
+
if (!nonblock)
force_page_cache_readahead(mapping, vma->vm_file,
pgoff, len >> PAGE_CACHE_SHIFT);
@@ -1356,19 +1372,9 @@ repeat:
return err;
}
} else {
- /*
- * If a nonlinear mapping then store the file page offset
- * in the pte.
- */
- unsigned long pgidx;
- pgidx = (addr - vma->vm_start) >> PAGE_SHIFT;
- pgidx += vma->vm_pgoff;
- pgidx >>= PAGE_CACHE_SHIFT - PAGE_SHIFT;
- if (pgoff != pgidx) {
- err = install_file_pte(mm, vma, addr, pgoff, prot);
- if (err)
- return err;
- }
+ err = install_file_pte(mm, vma, addr, pgoff, prot, linear);
+ if (err)
+ return err;
}
len -= PAGE_SIZE;
diff -puN mm/fremap.c~remap-file-pages-prot-2.6.4-rc1-mm1-A1 mm/fremap.c
--- 25/mm/fremap.c~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.526972968 -0800
+++ 25-akpm/mm/fremap.c 2004-03-30 20:44:54.545970080 -0800
@@ -53,7 +53,7 @@ static inline void zap_pte(struct mm_str
* previously existing mapping.
*/
int install_page(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long addr, struct page *page, pgprot_t prot)
+ unsigned long addr, struct page *page, pgprot_t pgprot)
{
int err = -ENOMEM;
pte_t *pte;
@@ -75,12 +75,19 @@ int install_page(struct mm_struct *mm, s
pte = pte_alloc_map(mm, pmd, addr);
if (!pte)
goto err_unlock;
+ /*
+ * Only install a new page for a non-shared mapping if it's
+ * not existent yet:
+ */
+ err = -EEXIST;
+ if (!pte_none(*pte) && !(vma->vm_flags & VM_SHARED))
+ goto err_unlock;
zap_pte(mm, vma, addr, pte);
inc_rss(mm, page);
flush_icache_page(vma, page);
- set_pte(pte, mk_pte(page, prot));
+ set_pte(pte, mk_pte(page, pgprot));
pte_chain = page_add_rmap(page, pte, pte_chain);
pte_val = *pte;
pte_unmap(pte);
@@ -103,7 +110,7 @@ EXPORT_SYMBOL(install_page);
* previously existing mapping.
*/
int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long addr, unsigned long pgoff, pgprot_t prot)
+ unsigned long addr, unsigned long pgoff, pgprot_t pgprot, int linear)
{
int err = -ENOMEM;
pte_t *pte;
@@ -111,6 +118,8 @@ int install_file_pte(struct mm_struct *m
pmd_t *pmd;
pte_t pte_val;
+ BUG_ON(!linear && !(vma->vm_flags & VM_SHARED));
+
pgd = pgd_offset(mm, addr);
spin_lock(&mm->page_table_lock);
@@ -121,10 +130,23 @@ int install_file_pte(struct mm_struct *m
pte = pte_alloc_map(mm, pmd, addr);
if (!pte)
goto err_unlock;
+ /*
+ * Skip linear non-existent ptes:
+ */
+ err = 0;
+ if (linear && pte_none(*pte))
+ goto err_unlock;
+ /*
+ * Only install a new page for a non-shared mapping if it's
+ * not existent yet:
+ */
+ err = -EEXIST;
+ if (!pte_none(*pte) && !(vma->vm_flags & VM_SHARED))
+ goto err_unlock;
zap_pte(mm, vma, addr, pte);
- set_pte(pte, pgoff_to_pte(pgoff));
+ set_pte(pte, pgoff_prot_to_pte(pgoff, pgprot));
pte_val = *pte;
pte_unmap(pte);
update_mmu_cache(vma, addr, pte_val);
@@ -144,27 +166,22 @@ err_unlock:
* @size: size of the remapped virtual memory range
* @prot: new protection bits of the range
* @pgoff: to be mapped page of the backing store file
- * @flags: 0 or MAP_NONBLOCKED - the later will cause no IO.
+ * @flags: bits MAP_INHERIT or MAP_NONBLOCKED - the later will cause no IO.
*
* this syscall works purely via pagetables, so it's the most efficient
* way to map the same (large) file into a given virtual window. Unlike
* mmap()/mremap() it does not create any new vmas. The new mappings are
* also safe across swapout.
- *
- * NOTE: the 'prot' parameter right now is ignored, and the vma's default
- * protection is used. Arbitrary protections might be implemented in the
- * future.
*/
-asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size,
- unsigned long __prot, unsigned long pgoff, unsigned long flags)
+long __remap_file_pages(struct mm_struct *mm, unsigned long start,
+ unsigned long size, unsigned long prot,
+ unsigned long pgoff, unsigned long flags)
{
- struct mm_struct *mm = current->mm;
+ pgprot_t pgprot = protection_map[calc_vm_prot_bits(prot) | VM_SHARED];
unsigned long end = start + size;
struct vm_area_struct *vma;
int err = -EINVAL;
- if (__prot)
- return err;
/*
* Sanitize the syscall parameters:
*/
@@ -184,37 +201,71 @@ asmlinkage long sys_remap_file_pages(uns
/* We need down_write() to change vma->vm_flags. */
down_write(&mm->mmap_sem);
vma = find_vma(mm, start);
-
/*
- * Make sure the vma is shared, that it supports prefaulting,
- * and that the remapped range is valid and fully within
- * the single existing vma:
- */
- if (vma && (vma->vm_flags & VM_SHARED) &&
- vma->vm_ops && vma->vm_ops->populate &&
- end > start && start >= vma->vm_start &&
- end <= vma->vm_end) {
-
- /* Must set VM_NONLINEAR before any pages are populated. */
- if (pgoff != ((start - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff)
- vma->vm_flags |= VM_NONLINEAR;
-
- /* ->populate can take a long time, so downgrade the lock. */
- downgrade_write(&mm->mmap_sem);
- err = vma->vm_ops->populate(vma, start, size,
- vma->vm_page_prot,
- pgoff, flags & MAP_NONBLOCK);
-
- /*
- * We can't clear VM_NONLINEAR because we'd have to do
- * it after ->populate completes, and that would prevent
- * downgrading the lock. (Locks can't be upgraded).
- */
- up_read(&mm->mmap_sem);
- } else {
- up_write(&mm->mmap_sem);
+ * Make sure the permissions are right, the vma is shared
+ * (or linearly remapped - ie. prefaulted), that it supports
+ * prefaulting, and that the remapped range is valid and fully
+ * within the single existing vma:
+ */
+ if (!vma)
+ goto out_unlock;
+ if (unlikely(flags & MAP_INHERIT))
+ pgprot = vma->vm_page_prot;
+ else {
+ err = -EPERM;
+ if (((prot & PROT_READ) && !(vma->vm_flags & VM_MAYREAD)))
+ goto out_unlock;
+ if (((prot & PROT_WRITE) && !(vma->vm_flags & VM_MAYWRITE)))
+ goto out_unlock;
+ if (((prot & PROT_EXEC) && !(vma->vm_flags & VM_MAYEXEC)))
+ goto out_unlock;
+ }
+
+ if (!vma->vm_ops || !vma->vm_ops->populate || end <= start ||
+ start < vma->vm_start || end > vma->vm_end)
+ goto out_unlock;
+
+ if (pgoff != ((start - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff) {
+ if (!(vma->vm_flags & VM_SHARED))
+ goto out_unlock;
+ vma->vm_flags |= VM_NONLINEAR;
}
+ /*
+ * ->populate can take a long time, so downgrade the lock:
+ */
+ downgrade_write(&mm->mmap_sem);
+ err = vma->vm_ops->populate(vma, start, size,
+ pgprot, pgoff, flags & MAP_NONBLOCK);
+
+ /*
+ * We can't clear VM_NONLINEAR because we'd have to do
+ * it after ->populate completes, and that would prevent
+ * downgrading the lock. (Locks can't be upgraded).
+ */
+ up_read(&mm->mmap_sem);
return err;
+
+out_unlock:
+ up_write(&mm->mmap_sem);
+ return err;
+}
+
+asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size,
+ unsigned long prot, unsigned long pgoff, unsigned long flags)
+{
+ return __remap_file_pages(current->mm, start, size, prot, pgoff, flags);
}
+/*
+ * sys_remap_file_pages - the old API. Implies MAP_INHERIT.
+ */
+asmlinkage long old_remap_file_pages(unsigned long start, unsigned long size,
+ unsigned long __prot, unsigned long pgoff, unsigned long flags)
+{
+ if (__prot)
+ return -EINVAL;
+
+ return __remap_file_pages(current->mm, start, size, PROT_NONE,
+ pgoff, flags | MAP_INHERIT);
+}
diff -puN mm/memory.c~remap-file-pages-prot-2.6.4-rc1-mm1-A1 mm/memory.c
--- 25/mm/memory.c~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.527972816 -0800
+++ 25-akpm/mm/memory.c 2004-03-30 20:44:54.546969928 -0800
@@ -1541,6 +1541,7 @@ static int do_file_page(struct mm_struct
unsigned long address, int write_access, pte_t *pte, pmd_t *pmd)
{
unsigned long pgoff;
+ pgprot_t pgprot;
int err;
BUG_ON(!vma->vm_ops || !vma->vm_ops->nopage);
@@ -1555,11 +1556,12 @@ static int do_file_page(struct mm_struct
}
pgoff = pte_to_pgoff(*pte);
+ pgprot = pte_to_pgprot(*pte);
pte_unmap(pte);
spin_unlock(&mm->page_table_lock);
- err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE, vma->vm_page_prot, pgoff, 0);
+ err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE, pgprot, pgoff, 0);
if (err == -ENOMEM)
return VM_FAULT_OOM;
if (err)
@@ -1608,6 +1610,15 @@ static inline int handle_pte_fault(struc
return do_swap_page(mm, vma, address, pte, pmd, entry, write_access);
}
+ /*
+ * Generate a SIGSEGV if a PROT_NONE page is accessed:
+ */
+ if (pgprot_val(pte_to_pgprot(entry)) == pgprot_val(__P000)) {
+ pte_unmap(pte);
+ spin_unlock(&mm->page_table_lock);
+ return VM_FAULT_SIGSEGV;
+ }
+
if (write_access) {
if (!pte_write(entry))
return do_wp_page(mm, vma, address, pte, pmd, entry);
diff -puN mm/mmap.c~remap-file-pages-prot-2.6.4-rc1-mm1-A1 mm/mmap.c
--- 25/mm/mmap.c~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.528972664 -0800
+++ 25-akpm/mm/mmap.c 2004-03-30 20:44:54.548969624 -0800
@@ -715,8 +715,12 @@ out:
}
if (flags & MAP_POPULATE) {
up_write(&mm->mmap_sem);
- sys_remap_file_pages(addr, len, prot,
- pgoff, flags & MAP_NONBLOCK);
+ /*
+ * remap_file_pages() works even if the mapping is private,
+ * in the linearly-mapped case:
+ */
+ __remap_file_pages(mm, addr, len, PROT_NONE, pgoff,
+ MAP_INHERIT | (flags & MAP_NONBLOCK));
down_write(&mm->mmap_sem);
}
return addr;
diff -puN mm/rmap.c~remap-file-pages-prot-2.6.4-rc1-mm1-A1 mm/rmap.c
--- 25/mm/rmap.c~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.530972360 -0800
+++ 25-akpm/mm/rmap.c 2004-03-30 20:44:54.548969624 -0800
@@ -343,6 +343,7 @@ static int fastcall try_to_unmap_one(str
BUG_ON(pte_file(*ptep));
} else {
unsigned long pgidx;
+ pgprot_t pgprot = pte_to_pgprot(pte);
/*
* If a nonlinear mapping then store the file page offset
* in the pte.
@@ -350,8 +351,10 @@ static int fastcall try_to_unmap_one(str
pgidx = (address - vma->vm_start) >> PAGE_SHIFT;
pgidx += vma->vm_pgoff;
pgidx >>= PAGE_CACHE_SHIFT - PAGE_SHIFT;
- if (page->index != pgidx) {
- set_pte(ptep, pgoff_to_pte(page->index));
+ if (page->index != pgidx ||
+ pgprot_val(pgprot) != pgprot_val(vma->vm_page_prot)) {
+
+ set_pte(ptep, pgoff_prot_to_pte(page->index, pgprot));
BUG_ON(!pte_file(*ptep));
}
}
diff -puN mm/shmem.c~remap-file-pages-prot-2.6.4-rc1-mm1-A1 mm/shmem.c
--- 25/mm/shmem.c~remap-file-pages-prot-2.6.4-rc1-mm1-A1 2004-03-30 20:44:54.531972208 -0800
+++ 25-akpm/mm/shmem.c 2004-03-30 20:44:54.555968560 -0800
@@ -1029,6 +1029,7 @@ static int shmem_populate(struct vm_area
struct mm_struct *mm = vma->vm_mm;
enum sgp_type sgp = nonblock? SGP_QUICK: SGP_CACHE;
unsigned long size;
+ int linear = !(vma->vm_flags & VM_NONLINEAR);
size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
if (pgoff >= size || pgoff + (len >> PAGE_SHIFT) > size)
@@ -1050,20 +1051,14 @@ static int shmem_populate(struct vm_area
page_cache_release(page);
return err;
}
- } else if (nonblock) {
+ } else {
/*
- * If a nonlinear mapping then store the file page
- * offset in the pte.
+ * Store the file page offset in the pte:
*/
- unsigned long pgidx;
- pgidx = (addr - vma->vm_start) >> PAGE_SHIFT;
- pgidx += vma->vm_pgoff;
- pgidx >>= PAGE_CACHE_SHIFT - PAGE_SHIFT;
- if (pgoff != pgidx) {
- err = install_file_pte(mm, vma, addr, pgoff, prot);
- if (err)
- return err;
- }
+ err = install_file_pte(mm, vma, addr,
+ pgoff, prot, linear);
+ if (err)
+ return err;
}
len -= PAGE_SIZE;
_