From 46dea3d092d23a58b42499cc8a21de0fad079f4a Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Sat, 29 Oct 2005 18:16:20 -0700 Subject: [PATCH] [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: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/ia64/mm/fault.c | 34 +++++++--------------------------- arch/ia64/mm/init.c | 2 +- include/linux/mm.h | 3 ++- mm/mmap.c | 17 ++++++++++++++--- 4 files changed, 24 insertions(+), 32 deletions(-) diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c index f21b5554978..af7eb087dca 100644 --- a/arch/ia64/mm/fault.c +++ b/arch/ia64/mm/fault.c @@ -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; diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c index 98246acd499..0063b2c5090 100644 --- a/arch/ia64/mm/init.c +++ b/arch/ia64/mm/init.c @@ -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(¤t->mm->mmap_sem); if (insert_vm_struct(current->mm, vma)) { up_write(¤t->mm->mmap_sem); diff --git a/include/linux/mm.h b/include/linux/mm.h index 7d4552fe086..89398032bc4 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -896,7 +896,8 @@ void handle_ra_miss(struct address_space *mapping, 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_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); diff --git a/mm/mmap.c b/mm/mmap.c index c43b2845700..d931d7e49ac 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -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) -- 2.41.1