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

[Christophe Leroy]

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

Fixes: da7bb43ab9da ("powerpc/32: Fix vmap stack - Properly set r1 before 
activating MMU")
Fixes: d2e006036082 ("powerpc/32: Use SPRN_SPRG_SCRATCH2 in exception prologs")
Cc: sta...@vger.kernel.org
Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
---
 arch/powerpc/kernel/head_book3s_32.S | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/powerpc/kernel/head_book3s_32.S 
b/arch/powerpc/kernel/head_book3s_32.S
index 349bf3f0c3af..fbc48a500846 100644
--- a/arch/powerpc/kernel/head_book3s_32.S
+++ b/arch/powerpc/kernel/head_book3s_32.S
@@ -260,9 +260,16 @@ __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
+#else
        mfspr   r11, SPRN_SPRG_THREAD
        lwz     r11, RTAS_SP(r11)
        cmpwi   cr1, r11, 0
+#endif
        bne     cr1, 7f
 #endif /* CONFIG_PPC_CHRP */
        EXCEPTION_PROLOG_1 for_rtas=1
-- 
2.25.0