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-rw-r--r--arch/tile/mm/mmap.c24
1 files changed, 22 insertions, 2 deletions
diff --git a/arch/tile/mm/mmap.c b/arch/tile/mm/mmap.c
index d67d91ebf63e..851a94e6ae58 100644
--- a/arch/tile/mm/mmap.c
+++ b/arch/tile/mm/mmap.c
@@ -58,16 +58,36 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
#else
int is_32bit = 0;
#endif
+ unsigned long random_factor = 0UL;
+
+ /*
+ * 8 bits of randomness in 32bit mmaps, 24 address space bits
+ * 12 bits of randomness in 64bit mmaps, 28 address space bits
+ */
+ if (current->flags & PF_RANDOMIZE) {
+ if (is_32bit)
+ random_factor = get_random_int() % (1<<8);
+ else
+ random_factor = get_random_int() % (1<<12);
+
+ random_factor <<= PAGE_SHIFT;
+ }
/*
* Use standard layout if the expected stack growth is unlimited
* or we are running native 64 bits.
*/
- if (!is_32bit || rlimit(RLIMIT_STACK) == RLIM_INFINITY) {
- mm->mmap_base = TASK_UNMAPPED_BASE;
+ if (rlimit(RLIMIT_STACK) == RLIM_INFINITY) {
+ mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
mm->get_unmapped_area = arch_get_unmapped_area;
} else {
mm->mmap_base = mmap_base(mm);
mm->get_unmapped_area = arch_get_unmapped_area_topdown;
}
}
+
+unsigned long arch_randomize_brk(struct mm_struct *mm)
+{
+ unsigned long range_end = mm->brk + 0x02000000;
+ return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
+}