powerpc/6xx: Fix power_save_ppc32_restore() with CONFIG_VMAP_STACK
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Message ID 7bce32ccbab3ba3e3e0f27da6961bf6313df97ed.1581663140.git.christophe.leroy@c-s.fr
State Accepted
Commit 477f3488a94e35380c82a7498d46f10fa5f3edd2
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Series
  • powerpc/6xx: Fix power_save_ppc32_restore() with CONFIG_VMAP_STACK
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snowpatch_ozlabs/apply_patch success Successfully applied on branch powerpc/merge (a5bc6e124219546a81ce334dc9b16483d55e9abf)

Commit Message

Christophe Leroy Feb. 14, 2020, 6:53 a.m. UTC
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.Finger@lwfinger.net>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Fixes: cd08f109e262 ("powerpc/32s: Enable CONFIG_VMAP_STACK")
Tested-by: Larry Finger <Larry.Finger@lwfinger.net>
---
 arch/powerpc/kernel/idle_6xx.S | 8 ++++++++
 1 file changed, 8 insertions(+)

Comments

Michael Ellerman Feb. 19, 2020, 12:40 p.m. UTC | #1
On Fri, 2020-02-14 at 06:53:00 UTC, Christophe Leroy wrote:
> 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.Finger@lwfinger.net>
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> Fixes: cd08f109e262 ("powerpc/32s: Enable CONFIG_VMAP_STACK")
> Tested-by: Larry Finger <Larry.Finger@lwfinger.net>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/477f3488a94e35380c82a7498d46f10fa5f3edd2

cheers

Patch
diff mbox series

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)