From: Christophe Leroy <christophe.le...@csgroup.eu>

commit 2c637d2df4ee4830e9d3eb2bd5412250522ce96e upstream.

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.

Fixes: a68c31fc01ef ("powerpc/32s: Implement Kernel Userspace Access 
Protection")
Fixes: 31ed2b13c48d ("powerpc/32s: Implement Kernel Userspace Execution 
Prevention.")
Cc: sta...@vger.kernel.org
Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
Link: 
https://lore.kernel.org/r/21b05f7298c1b18f73e6e5b4cd5005aafa24b6da.1599820109.git.christophe.le...@csgroup.eu
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 arch/powerpc/kernel/head_32.S           |    2 +-
 arch/powerpc/platforms/powermac/sleep.S |    9 +--------
 2 files changed, 2 insertions(+), 9 deletions(-)

--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -843,7 +843,7 @@ BEGIN_MMU_FTR_SECTION
 END_MMU_FTR_SECTION_IFSET(MMU_FTR_USE_HIGH_BATS)
        blr
 
-load_segment_registers:
+_GLOBAL(load_segment_registers)
        li      r0, NUM_USER_SEGMENTS /* load up user segment register values */
        mtctr   r0              /* for context 0 */
        li      r3, 0           /* Kp = 0, Ks = 0, VSID = 0 */
--- a/arch/powerpc/platforms/powermac/sleep.S
+++ b/arch/powerpc/platforms/powermac/sleep.S
@@ -293,14 +293,7 @@ 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
 


Reply via email to