linux-kernel - [PATCH 5.13 138/151] powerpc/32s: Fix napping restore in data storage interrupt (DSI)

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Date:   Mon, 16 Aug 2021 15:02:48 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Finn Thain <fthain@...ux-m68k.org>,
        Christophe Leroy <christophe.leroy@...roup.eu>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH 5.13 138/151] powerpc/32s: Fix napping restore in data storage interrupt (DSI)

From: Christophe Leroy <christophe.leroy@...roup.eu>

commit 62376365048878f770d8b7d11b89b8b3e18018f1 upstream.

When a DSI (Data Storage Interrupt) is taken while in NAP mode,
r11 doesn't survive the call to power_save_ppc32_restore().

So use r1 instead of r11 as they both contain the virtual stack
pointer at that point.

Fixes: 4c0104a83fc3 ("powerpc/32: Dismantle EXC_XFER_STD/LITE/TEMPLATE")
Cc: stable@...r.kernel.org # v5.13+
Reported-by: Finn Thain <fthain@...ux-m68k.org>
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Link: https://lore.kernel.org/r/731694e0885271f6ee9ffc179eb4bcee78313682.1628003562.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/powerpc/kernel/head_book3s_32.S |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/powerpc/kernel/head_book3s_32.S
+++ b/arch/powerpc/kernel/head_book3s_32.S
@@ -300,7 +300,7 @@ ALT_MMU_FTR_SECTION_END_IFSET(MMU_FTR_HP
 	EXCEPTION_PROLOG_1
 	EXCEPTION_PROLOG_2 INTERRUPT_DATA_STORAGE DataAccess handle_dar_dsisr=1
 	prepare_transfer_to_handler
-	lwz	r5, _DSISR(r11)
+	lwz	r5, _DSISR(r1)
 	andis.	r0, r5, DSISR_DABRMATCH@h
 	bne-	1f
 	bl	do_page_fault