diff options
Diffstat (limited to 'arch/x86/mm/mmap.c')
| -rw-r--r-- | arch/x86/mm/mmap.c | 53 |
1 files changed, 27 insertions, 26 deletions
diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c index 56fe7124fbe..25e7e1372bb 100644 --- a/arch/x86/mm/mmap.c +++ b/arch/x86/mm/mmap.c @@ -4,7 +4,7 @@ * Based on code by Ingo Molnar and Andi Kleen, copyrighted * as follows: * - * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina. + * Copyright 2003-2009 Red Hat Inc. * All Rights Reserved. * Copyright 2005 Andi Kleen, SUSE Labs. * Copyright 2007 Jiri Kosina, SUSE Labs. @@ -29,36 +29,37 @@ #include <linux/random.h> #include <linux/limits.h> #include <linux/sched.h> +#include <asm/elf.h> + +struct __read_mostly va_alignment va_align = { + .flags = -1, +}; + +static unsigned int stack_maxrandom_size(void) +{ + unsigned int max = 0; + if ((current->flags & PF_RANDOMIZE) && + !(current->personality & ADDR_NO_RANDOMIZE)) { + max = ((-1U) & STACK_RND_MASK) << PAGE_SHIFT; + } + + return max; +} /* * Top of mmap area (just below the process stack). * - * Leave an at least ~128 MB hole. + * Leave an at least ~128 MB hole with possible stack randomization. */ -#define MIN_GAP (128*1024*1024) +#define MIN_GAP (128*1024*1024UL + stack_maxrandom_size()) #define MAX_GAP (TASK_SIZE/6*5) -/* - * True on X86_32 or when emulating IA32 on X86_64 - */ -static int mmap_is_ia32(void) -{ -#ifdef CONFIG_X86_32 - return 1; -#endif -#ifdef CONFIG_IA32_EMULATION - if (test_thread_flag(TIF_IA32)) - return 1; -#endif - return 0; -} - static int mmap_is_legacy(void) { if (current->personality & ADDR_COMPAT_LAYOUT) return 1; - if (current->signal->rlim[RLIMIT_STACK].rlim_cur == RLIM_INFINITY) + if (rlimit(RLIMIT_STACK) == RLIM_INFINITY) return 1; return sysctl_legacy_va_layout; @@ -74,16 +75,16 @@ static unsigned long mmap_rnd(void) */ if (current->flags & PF_RANDOMIZE) { if (mmap_is_ia32()) - rnd = (long)get_random_int() % (1<<8); + rnd = get_random_int() % (1<<8); else - rnd = (long)(get_random_int() % (1<<28)); + rnd = get_random_int() % (1<<28); } return rnd << PAGE_SHIFT; } static unsigned long mmap_base(void) { - unsigned long gap = current->signal->rlim[RLIMIT_STACK].rlim_cur; + unsigned long gap = rlimit(RLIMIT_STACK); if (gap < MIN_GAP) gap = MIN_GAP; @@ -111,13 +112,13 @@ static unsigned long mmap_legacy_base(void) */ void arch_pick_mmap_layout(struct mm_struct *mm) { + mm->mmap_legacy_base = mmap_legacy_base(); + mm->mmap_base = mmap_base(); + if (mmap_is_legacy()) { - mm->mmap_base = mmap_legacy_base(); + mm->mmap_base = mm->mmap_legacy_base; mm->get_unmapped_area = arch_get_unmapped_area; - mm->unmap_area = arch_unmap_area; } else { - mm->mmap_base = mmap_base(); mm->get_unmapped_area = arch_get_unmapped_area_topdown; - mm->unmap_area = arch_unmap_area_topdown; } } |