From 2dadb987e09995b2910c419cdfe2307e66537649 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Sun, 22 Feb 2009 01:50:02 +0000 Subject: powerpc: More stack randomisation for 64bit binaries At the moment we randomise the stack by 8MB on 32bit and 64bit tasks. Since we have a lot more address space to play with on 64bit, lets do what x86 does and increase that randomisation to 1GB: before: # for i in seq `1 10` ; do sleep 1 & cat /proc/${!}/maps | grep stack; done fffffebc000-fffffed1000 rw-p ffffffeb000 00:00 0 [stack] ffffff5a000-ffffff6f000 rw-p ffffffeb000 00:00 0 [stack] fffffdb2000-fffffdc7000 rw-p ffffffeb000 00:00 0 [stack] fffffd3e000-fffffd53000 rw-p ffffffeb000 00:00 0 [stack] fffffad9000-fffffaee000 rw-p ffffffeb000 00:00 0 [stack] after: # for i in seq `1 10` ; do sleep 1 & cat /proc/${!}/maps | grep stack; done ffff5c27000-ffff5c3c000 rw-p ffffffeb000 00:00 0 [stack] fffebe5e000-fffebe73000 rw-p ffffffeb000 00:00 0 [stack] fffcb298000-fffcb2ad000 rw-p ffffffeb000 00:00 0 [stack] fffc719d000-fffc71b2000 rw-p ffffffeb000 00:00 0 [stack] fffe01af000-fffe01c4000 rw-p ffffffeb000 00:00 0 [stack] Signed-off-by: Anton Blanchard Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/elf.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch/powerpc/include/asm/elf.h') diff --git a/arch/powerpc/include/asm/elf.h b/arch/powerpc/include/asm/elf.h index c125da793b07..3f94d8880e6c 100644 --- a/arch/powerpc/include/asm/elf.h +++ b/arch/powerpc/include/asm/elf.h @@ -271,6 +271,11 @@ extern int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp); #define VDSO_AUX_ENT(a,b) NEW_AUX_ENT(a,b); +/* 1GB for 64bit, 8MB for 32bit */ +#define STACK_RND_MASK (is_32bit_task() ? \ + (0x7ff >> (PAGE_SHIFT - 12)) : \ + (0x3ffff >> (PAGE_SHIFT - 12))) + #endif /* __KERNEL__ */ /* -- cgit