* [PATCH] powerpc/6xx: Fix power_save_ppc32_restore() with CONFIG_VMAP_STACK
@ 2020-02-14 6:53 Christophe Leroy
2020-02-19 12:40 ` Michael Ellerman
0 siblings, 1 reply; 2+ messages in thread
From: Christophe Leroy @ 2020-02-14 6:53 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman, Larry Finger
Cc: linux-kernel, linuxppc-dev
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(+)
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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] powerpc/6xx: Fix power_save_ppc32_restore() with CONFIG_VMAP_STACK
2020-02-14 6:53 [PATCH] powerpc/6xx: Fix power_save_ppc32_restore() with CONFIG_VMAP_STACK Christophe Leroy
@ 2020-02-19 12:40 ` Michael Ellerman
0 siblings, 0 replies; 2+ messages in thread
From: Michael Ellerman @ 2020-02-19 12:40 UTC (permalink / raw)
To: Christophe Leroy, Benjamin Herrenschmidt, Paul Mackerras, Larry Finger
Cc: linuxppc-dev, linux-kernel
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
^ permalink raw reply [flat|nested] 2+ messages in thread
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