Commit 98bf2d3f authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

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: da7bb43a ("powerpc/32: Fix vmap stack - Properly set r1 before activating MMU")
Fixes: d2e00603 ("powerpc/32: Use SPRN_SPRG_SCRATCH2 in exception prologs")
Cc: stable@vger.kernel.org # v5.10+
Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Squash in fixup for RTAS machine check from Christophe]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/bc77d61d1c18940e456a2dee464f1e2eda65a3f0.1608621048.git.christophe.leroy@csgroup.eu
parent e71ba945

arch/powerpc/kernel/head_book3s_32.S

+9 −0
Original line number Diff line number Diff line
@@ -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