- Add documentation.
- It's an x86-only feature, so don't offer the sysctl on other architectures.
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/Documentation/filesystems/proc.txt | 6 ++++++
25-akpm/arch/i386/mm/mmap.c | 3 ++-
25-akpm/include/asm-i386/page.h | 4 ++--
25-akpm/kernel/sysctl.c | 5 +++++
4 files changed, 15 insertions(+), 3 deletions(-)
diff -puN Documentation/filesystems/proc.txt~legacy_va_layout-docs Documentation/filesystems/proc.txt
--- 25/Documentation/filesystems/proc.txt~legacy_va_layout-docs Wed Aug 4 16:46:45 2004
+++ 25-akpm/Documentation/filesystems/proc.txt Wed Aug 4 16:47:02 2004
@@ -1174,6 +1174,12 @@ for writeout by the pdflush daemons. It
Data which has been dirty in-memory for longer than this interval will be
written out next time a pdflush daemon wakes up.
+legacy_va_layout
+----------------
+
+If non-zero, this sysctl disables the new 32-bit mmap mmap layout - the kernel
+will use the legacy (2.4) layout for all processes.
+
lower_zone_protection
---------------------
diff -puN kernel/sysctl.c~legacy_va_layout-docs kernel/sysctl.c
--- 25/kernel/sysctl.c~legacy_va_layout-docs Wed Aug 4 16:46:45 2004
+++ 25-akpm/kernel/sysctl.c Wed Aug 4 16:46:45 2004
@@ -42,6 +42,7 @@
#include <linux/dcache.h>
#include <asm/uaccess.h>
+#include <asm/processor.h>
#ifdef CONFIG_ROOT_NFS
#include <linux/nfs_fs.h>
@@ -149,7 +150,9 @@ extern ctl_table random_table[];
extern ctl_table pty_table[];
#endif
+#ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
int sysctl_legacy_va_layout;
+#endif
/* /proc declarations: */
@@ -807,6 +810,7 @@ static ctl_table vm_table[] = {
.strategy = &sysctl_intvec,
.extra1 = &zero,
},
+#ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
{
.ctl_name = VM_LEGACY_VA_LAYOUT,
.procname = "legacy_va_layout",
@@ -817,6 +821,7 @@ static ctl_table vm_table[] = {
.strategy = &sysctl_intvec,
.extra1 = &zero,
},
+#endif
{ .ctl_name = 0 }
};
diff -puN include/asm-i386/page.h~legacy_va_layout-docs include/asm-i386/page.h
--- 25/include/asm-i386/page.h~legacy_va_layout-docs Wed Aug 4 16:46:45 2004
+++ 25-akpm/include/asm-i386/page.h Wed Aug 4 16:46:45 2004
@@ -118,6 +118,8 @@ static __inline__ int get_order(unsigned
extern int devmem_is_allowed(unsigned long pagenr);
+extern int sysctl_legacy_va_layout;
+
#endif /* __ASSEMBLY__ */
#ifdef __ASSEMBLY__
@@ -147,8 +149,6 @@ extern int devmem_is_allowed(unsigned lo
((current->personality & READ_IMPLIES_EXEC) ? VM_EXEC : 0 ) | \
VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
-
-
#endif /* __KERNEL__ */
#endif /* _I386_PAGE_H */
diff -puN arch/i386/mm/mmap.c~legacy_va_layout-docs arch/i386/mm/mmap.c
--- 25/arch/i386/mm/mmap.c~legacy_va_layout-docs Wed Aug 4 16:46:45 2004
+++ 25-akpm/arch/i386/mm/mmap.c Wed Aug 4 16:46:45 2004
@@ -57,7 +57,8 @@ void arch_pick_mmap_layout(struct mm_str
* Fall back to the standard layout if the personality
* bit is set, or if the expected stack growth is unlimited:
*/
- if (sysctl_legacy_va_layout || (current->personality & ADDR_COMPAT_LAYOUT) ||
+ if (sysctl_legacy_va_layout ||
+ (current->personality & ADDR_COMPAT_LAYOUT) ||
current->rlim[RLIMIT_STACK].rlim_cur == RLIM_INFINITY) {
mm->mmap_base = TASK_UNMAPPED_BASE;
mm->get_unmapped_area = arch_get_unmapped_area;
_