powerpc/32s: Fix RTAS machine check with VMAP stack

When we have VMAP stack, exception prolog 1 sets r1, not r11.

When it is not an RTAS machine check, don't trash r1 because it is
needed by prolog 1.

Fixes: da7bb43ab9 ("powerpc/32: Fix vmap stack - Properly set r1 before activating MMU")
Fixes: d2e0060360 ("powerpc/32: Use SPRN_SPRG_SCRATCH2 in exception prologs")
Cc: stable@vger.kernel.org # v5.10+
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Squash in fixup for RTAS machine check from Christophe]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/bc77d61d1c18940e456a2dee464f1e2eda65a3f0.1608621048.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2020-12-22 07:11:18 +00:00 committed by Michael Ellerman
parent e71ba9452f
commit 98bf2d3f49

View File

@ -260,10 +260,19 @@ __secondary_hold_acknowledge:
MachineCheck:
EXCEPTION_PROLOG_0
#ifdef CONFIG_PPC_CHRP
#ifdef CONFIG_VMAP_STACK
mtspr SPRN_SPRG_SCRATCH2,r1
mfspr r1, SPRN_SPRG_THREAD
lwz r1, RTAS_SP(r1)
cmpwi cr1, r1, 0
bne cr1, 7f
mfspr r1, SPRN_SPRG_SCRATCH2
#else
mfspr r11, SPRN_SPRG_THREAD
lwz r11, RTAS_SP(r11)
cmpwi cr1, r11, 0
bne cr1, 7f
#endif
#endif /* CONFIG_PPC_CHRP */
EXCEPTION_PROLOG_1 for_rtas=1
7: EXCEPTION_PROLOG_2