From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Larry Finger <Larry.Finger@lwfinger.net>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH] powerpc/6xx: Fix power_save_ppc32_restore() with CONFIG_VMAP_STACK
Date: Fri, 14 Feb 2020 06:53:00 +0000 (UTC) [thread overview]
Message-ID: <7bce32ccbab3ba3e3e0f27da6961bf6313df97ed.1581663140.git.christophe.leroy@c-s.fr> (raw)
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
next reply other threads:[~2020-02-14 6:53 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-14 6:53 Christophe Leroy [this message]
2020-02-19 12:40 ` [PATCH] powerpc/6xx: Fix power_save_ppc32_restore() with CONFIG_VMAP_STACK Michael Ellerman
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