linux-kernel - [PATCH 4.19 108/346] ARM: p2v: fix handling of LPAE translation in BE mode

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Date:   Mon, 28 Dec 2020 13:47:07 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Nicolas Pitre <nico@...xnic.net>,
        Linus Walleij <linus.walleij@...aro.org>,
        Ard Biesheuvel <ardb@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 108/346] ARM: p2v: fix handling of LPAE translation in BE mode

From: Ard Biesheuvel <ardb@...nel.org>

[ Upstream commit 4e79f0211b473f8e1eab8211a9fd50cc41a3a061 ]

When running in BE mode on LPAE hardware with a PA-to-VA translation
that exceeds 4 GB, we patch bits 39:32 of the offset into the wrong
byte of the opcode. So fix that, by rotating the offset in r0 to the
right by 8 bits, which will put the 8-bit immediate in bits 31:24.

Note that this will also move bit #22 in its correct place when
applying the rotation to the constant #0x400000.

Fixes: d9a790df8e984 ("ARM: 7883/1: fix mov to mvn conversion in case of 64 bit phys_addr_t and BE")
Acked-by: Nicolas Pitre <nico@...xnic.net>
Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
Signed-off-by: Ard Biesheuvel <ardb@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/arm/kernel/head.S | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 6b1148cafffdb..90add5ded3f1f 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -674,12 +674,8 @@ ARM_BE8(rev16	ip, ip)
 	ldrcc	r7, [r4], #4	@ use branch for delay slot
 	bcc	1b
 	bx	lr
-#else
-#ifdef CONFIG_CPU_ENDIAN_BE8
-	moveq	r0, #0x00004000	@ set bit 22, mov to mvn instruction
 #else
 	moveq	r0, #0x400000	@ set bit 22, mov to mvn instruction
-#endif
 	b	2f
 1:	ldr	ip, [r7, r3]
 #ifdef CONFIG_CPU_ENDIAN_BE8
@@ -688,7 +684,7 @@ ARM_BE8(rev16	ip, ip)
 	tst	ip, #0x000f0000	@ check the rotation field
 	orrne	ip, ip, r6, lsl #24 @ mask in offset bits 31-24
 	biceq	ip, ip, #0x00004000 @ clear bit 22
-	orreq	ip, ip, r0      @ mask in offset bits 7-0
+	orreq	ip, ip, r0, ror #8  @ mask in offset bits 7-0
 #else
 	bic	ip, ip, #0x000000ff
 	tst	ip, #0xf00	@ check the rotation field
-- 
2.27.0