diff options
| author | Andi Kleen <ak@suse.de> | 2006-01-17 07:03:38 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-01-16 23:18:35 -0800 |
| commit | 8817210d4d968e58f7d93db2eecd17b20dd03d40 (patch) | |
| tree | 4a4084011f348f44c388e1876e55c0d2a03f46b4 /arch/x86_64/mm/mmap.c | |
| parent | 562795fe5770d0c7ee7fe269890e37d9fd475fdf (diff) | |
[PATCH] x86_64: Flexmap for 32bit and randomized mappings for 64bit
Another try at this.
For 32bit follow the 32bit implementation from Ingo -
mappings are growing down from the end of stack now
and vary randomly by 1GB.
Randomized mappings for 64bit just vary the normal mmap break
by 1TB. I didn't bother implementing full flex mmap for 64bit
because it shouldn't be needed there.
Cc: mingo@elte.hu
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/x86_64/mm/mmap.c')
| -rw-r--r-- | arch/x86_64/mm/mmap.c | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/arch/x86_64/mm/mmap.c b/arch/x86_64/mm/mmap.c new file mode 100644 index 00000000000..43e9b99bdf2 --- /dev/null +++ b/arch/x86_64/mm/mmap.c @@ -0,0 +1,30 @@ +/* Copyright 2005 Andi Kleen, SuSE Labs. + * Licensed under GPL, v.2 + */ +#include <linux/config.h> +#include <linux/mm.h> +#include <linux/sched.h> +#include <linux/random.h> +#include <asm/ia32.h> + +/* Notebook: move the mmap code from sys_x86_64.c over here. */ + +void arch_pick_mmap_layout(struct mm_struct *mm) +{ +#ifdef CONFIG_IA32_EMULATION + if (current_thread_info()->flags & _TIF_IA32) + return ia32_pick_mmap_layout(mm); +#endif + mm->mmap_base = TASK_UNMAPPED_BASE; + if (current->flags & PF_RANDOMIZE) { + /* Add 28bit randomness which is about 40bits of address space + because mmap base has to be page aligned. + or ~1/128 of the total user VM + (total user address space is 47bits) */ + unsigned rnd = get_random_int() & 0xfffffff; + mm->mmap_base += ((unsigned long)rnd) << PAGE_SHIFT; + } + mm->get_unmapped_area = arch_get_unmapped_area; + mm->unmap_area = arch_unmap_area; +} + |