Re: [PATCH] powerpc/powermac: Fix low_sleep_handler with KUAP and KUEP
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2020-09-10 23:56:19
Also in:
lkml
Christophe Leroy [off-list ref] writes:
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 <redacted>
Fixes: a68c31fc01ef ("powerpc/32s: Implement Kernel Userspace Access Protection")
Fixes: 31ed2b13c48d ("powerpc/32s: Implement Kernel Userspace Execution Prevention.")
Cc: stable@vger.kernel.org
---
arch/powerpc/platforms/powermac/sleep.S | 9 +--------
1 file changed, 1 insertion(+), 8 deletions(-)Doesn't build? pmac32_defconfig, gcc 9.3.0: ld: arch/powerpc/platforms/powermac/sleep.o: in function `core99_wake_up': (.text+0x25c): undefined reference to `load_segment_registers' Missing _GLOBAL() presumably? cheers
quoted hunk ↗ jump to hunk
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