[v3,4/7] arm64: Use simpler API for random address requests

Commit Message

Jason Cooper Aug. 3, 2016, 11:39 p.m. UTC

Currently, all callers to randomize_range() set the length to 0 and
calculate end by adding a constant to the start address.  We can
simplify the API to remove a bunch of needless checks and variables.

Use the new randomize_addr(start, range) call to set the requested
address.

Signed-off-by: Jason Cooper <[e-mail]>
Acked-by: Will Deacon <[e-mail]>
---
Changes from v2:
 - s/randomize_addr/randomize_page/ (Kees Cook)

 arch/arm64/kernel/process.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

Patch

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 6cd2612236dc..6ac2950ffb78 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -374,12 +374,8 @@  unsigned long arch_align_stack(unsigned long sp)
 
 unsigned long arch_randomize_brk(struct mm_struct *mm)
 {
-	unsigned long range_end = mm->brk;
-
 	if (is_compat_task())
-		range_end += 0x02000000;
+		return randomize_page(mm->brk, 0x02000000);
 	else
-		range_end += 0x40000000;
-
-	return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
+		return randomize_page(mm->brk, 0x40000000);
 }