[PATCH] powerpc/powermac: Fix low_sleep_handler with KUAP and KUEP

From: Christophe Leroy
Date: Tue Sep 01 2020 - 03:35:49 EST


low_sleep_handler() has an hardcoded restore of segment registers
that doesn't take KUAP and KUEP into account.

Use head_32's load_segment_registers() routine instead.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Fixes: a68c31fc01ef ("powerpc/32s: Implement Kernel Userspace Access Protection")
Fixes: 31ed2b13c48d ("powerpc/32s: Implement Kernel Userspace Execution Prevention.")
Cc: stable@xxxxxxxxxxxxxxx
---
arch/powerpc/platforms/powermac/sleep.S | 9 +--------
1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/arch/powerpc/platforms/powermac/sleep.S b/arch/powerpc/platforms/powermac/sleep.S
index f9a680fdd9c4..51bfdfe85058 100644
--- a/arch/powerpc/platforms/powermac/sleep.S
+++ b/arch/powerpc/platforms/powermac/sleep.S
@@ -294,14 +294,7 @@ grackle_wake_up:
* we do any r1 memory access as we are not sure they
* are in a sane state above the first 256Mb region
*/
- li r0,16 /* load up segment register values */
- mtctr r0 /* for context 0 */
- lis r3,0x2000 /* Ku = 1, VSID = 0 */
- li r4,0
-3: mtsrin r3,r4
- addi r3,r3,0x111 /* increment VSID */
- addis r4,r4,0x1000 /* address of next segment */
- bdnz 3b
+ bl load_segment_registers
sync
isync

--
2.25.0