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guard page for stacks that grow upwards

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pa-risc and ia64 have stacks that grow upwards. Check that
they do not run into other mappings. By making VM_GROWSUP
0x0 on architectures that do not ever use it, we can avoid
some unpleasant #ifdefs in check_stack_guard_page().

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Luck, Tony
2010-08-24 11:44:18 -07:00
committed by Linus Torvalds
parent 9559fcdbff
commit 8ca3eb0809
3 changed files with 18 additions and 8 deletions
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8
include/linux/mm.h
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@@ -78,7 +78,11 @@ extern unsigned int kobjsize(const void *objp);
#define VM_MAYSHARE 0x00000080
#define VM_GROWSDOWN 0x00000100 /* general info on the segment */
#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
#define VM_GROWSUP 0x00000200
#else
#define VM_GROWSUP 0x00000000
#endif
#define VM_PFNMAP 0x00000400 /* Page-ranges managed without "struct page", just pure PFN */
#define VM_DENYWRITE 0x00000800 /* ETXTBSY on write attempts.. */
@@ -1330,8 +1334,10 @@ unsigned long ra_submit(struct file_ra_state *ra,
/* Do stack extension */
extern int expand_stack(struct vm_area_struct *vma, unsigned long address);
#ifdef CONFIG_IA64
#if VM_GROWSUP
extern int expand_upwards(struct vm_area_struct *vma, unsigned long address);
#else
#define expand_upwards(vma, address) do { } while (0)
#endif
extern int expand_stack_downwards(struct vm_area_struct *vma,
unsigned long address);