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[PATCH] mm: ia64 use expand_upwards

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ia64 has expand_backing_store function for growing its Register Backing Store
vma upwards.  But more complete code for this purpose is found in the
CONFIG_STACK_GROWSUP part of mm/mmap.c.  Uglify its #ifdefs further to provide
expand_upwards for ia64 as well as expand_stack for parisc.

The Register Backing Store vma should be marked VM_ACCOUNT.  Implement the
intention of growing it only a page at a time, instead of passing an address
outside of the vma to handle_mm_fault, with unknown consequences.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Hugh Dickins
2005-10-29 18:16:20 -07:00
committed by Linus Torvalds
parent f449952bc8
commit 46dea3d092
4 changed files with 24 additions and 32 deletions
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34
arch/ia64/mm/fault.c
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@@ -19,32 +19,6 @@
extern void die (char *, struct pt_regs *, long);
/*
* This routine is analogous to expand_stack() but instead grows the
* register backing store (which grows towards higher addresses).
* Since the register backing store is access sequentially, we
* disallow growing the RBS by more than a page at a time. Note that
* the VM_GROWSUP flag can be set on any VM area but that's fine
* because the total process size is still limited by RLIMIT_STACK and
* RLIMIT_AS.
*/
static inline long
expand_backing_store (struct vm_area_struct *vma, unsigned long address)
{
unsigned long grow;
grow = PAGE_SIZE >> PAGE_SHIFT;
if (address - vma->vm_start > current->signal->rlim[RLIMIT_STACK].rlim_cur
|| (((vma->vm_mm->total_vm + grow) << PAGE_SHIFT) > current->signal->rlim[RLIMIT_AS].rlim_cur))
return -ENOMEM;
vma->vm_end += PAGE_SIZE;
vma->vm_mm->total_vm += grow;
if (vma->vm_flags & VM_LOCKED)
vma->vm_mm->locked_vm += grow;
vm_stat_account(vma->vm_mm, vma->vm_flags, vma->vm_file, grow);
return 0;
}
/*
* Return TRUE if ADDRESS points at a page in the kernel's mapped segment
* (inside region 5, on ia64) and that page is present.
@@ -185,7 +159,13 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
if (REGION_NUMBER(address) != REGION_NUMBER(vma->vm_start)
|| REGION_OFFSET(address) >= RGN_MAP_LIMIT)
goto bad_area;
if (expand_backing_store(vma, address))
/*
* Since the register backing store is accessed sequentially,
* we disallow growing it by more than a page at a time.
*/
if (address > vma->vm_end + PAGE_SIZE - sizeof(long))
goto bad_area;
if (expand_upwards(vma, address))
goto bad_area;
}
goto good_area;