Commit 46dea3d0 authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
Browse files

[PATCH] mm: ia64 use expand_upwards 



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: default avatarHugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent f449952b

arch/ia64/mm/fault.c

+7 −27
Original line number Diff line number Diff line
@@ -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;

arch/ia64/mm/init.c

+1 −1
Original line number Diff line number Diff line
@@ -158,7 +158,7 @@ ia64_init_addr_space (void) 
		vma->vm_start = current->thread.rbs_bot & PAGE_MASK;

		vma->vm_end = vma->vm_start + PAGE_SIZE;

		vma->vm_page_prot = protection_map[VM_DATA_DEFAULT_FLAGS & 0x7];

		vma->vm_flags = VM_DATA_DEFAULT_FLAGS | VM_GROWSUP;

		vma->vm_flags = VM_DATA_DEFAULT_FLAGS|VM_GROWSUP|VM_ACCOUNT;

		down_write(&current->mm->mmap_sem);

		if (insert_vm_struct(current->mm, vma)) {

			up_write(&current->mm->mmap_sem);

include/linux/mm.h

+2 −1
Original line number Diff line number Diff line
@@ -897,6 +897,7 @@ unsigned long max_sane_readahead(unsigned long nr); 


/* Do stack extension */

extern int expand_stack(struct vm_area_struct *vma, unsigned long address);

extern int expand_upwards(struct vm_area_struct *vma, unsigned long address);



/* Look up the first VMA which satisfies  addr < vm_end,  NULL if none. */

extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr);

mm/mmap.c

+14 −3
Original line number Diff line number Diff line
@@ -1508,11 +1508,15 @@ static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, un 
	return 0;

}



#ifdef CONFIG_STACK_GROWSUP

#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)

/*

 * vma is the first one with address > vma->vm_end.  Have to extend vma.

 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.

 * vma is the last one with address > vma->vm_end.  Have to extend vma.

 */

int expand_stack(struct vm_area_struct * vma, unsigned long address)

#ifdef CONFIG_STACK_GROWSUP

static inline

#endif

int expand_upwards(struct vm_area_struct *vma, unsigned long address)

{

	int error;
@@ -1550,6 +1554,13 @@ int expand_stack(struct vm_area_struct * vma, unsigned long address) 
	anon_vma_unlock(vma);

	return error;

}

#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */



#ifdef CONFIG_STACK_GROWSUP

int expand_stack(struct vm_area_struct *vma, unsigned long address)

{

	return expand_upwards(vma, address);

}



struct vm_area_struct *

find_extend_vma(struct mm_struct *mm, unsigned long addr)

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