[PATCH] powerpc/6xx: Fix power_save_ppc32_restore() with CONFIG_VMAP_STACK

[Christophe Leroy]

power_save_ppc32_restore() is called during exception entry, before
re-enabling the MMU. It substracts KERNELBASE from the address
of nap_save_msscr0 to access it.

With CONFIG_VMAP_STACK enabled, data MMU translation has already been
re-enabled, so power_save_ppc32_restore() has to access
nap_save_msscr0 by its virtual address.

Reported-by: Larry Finger <larry.fin...@lwfinger.net>
Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr>
Fixes: cd08f109e262 ("powerpc/32s: Enable CONFIG_VMAP_STACK")
Tested-by: Larry Finger <larry.fin...@lwfinger.net>
---
 arch/powerpc/kernel/idle_6xx.S | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/powerpc/kernel/idle_6xx.S b/arch/powerpc/kernel/idle_6xx.S
index 0ffdd18b9f26..433d97bea1f3 100644
--- a/arch/powerpc/kernel/idle_6xx.S
+++ b/arch/powerpc/kernel/idle_6xx.S
@@ -166,7 +166,11 @@ BEGIN_FTR_SECTION
        mfspr   r9,SPRN_HID0
        andis.  r9,r9,HID0_NAP@h
        beq     1f
+#ifdef CONFIG_VMAP_STACK
+       addis   r9, r11, nap_save_msscr0@ha
+#else
        addis   r9,r11,(nap_save_msscr0-KERNELBASE)@ha
+#endif
        lwz     r9,nap_save_msscr0@l(r9)
        mtspr   SPRN_MSSCR0, r9
        sync
@@ -174,7 +178,11 @@ BEGIN_FTR_SECTION
 1:
 END_FTR_SECTION_IFSET(CPU_FTR_NAP_DISABLE_L2_PR)
 BEGIN_FTR_SECTION
+#ifdef CONFIG_VMAP_STACK
+       addis   r9, r11, nap_save_hid1@ha
+#else
        addis   r9,r11,(nap_save_hid1-KERNELBASE)@ha
+#endif
        lwz     r9,nap_save_hid1@l(r9)
        mtspr   SPRN_HID1, r9
 END_FTR_SECTION_IFSET(CPU_FTR_DUAL_PLL_750FX)
-- 
2.25.0