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From: ben.dooks@codethink.co.uk (Ben Dooks)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 02/10] ARM: fixup_pv_table bug when CPU_ENDIAN_BE8
Date: Wed, 19 Jun 2013 13:36:38 +0100	[thread overview]
Message-ID: <1371645406-16873-3-git-send-email-ben.dooks@codethink.co.uk> (raw)
In-Reply-To: <1371645406-16873-1-git-send-email-ben.dooks@codethink.co.uk>

The fixup_pv_table assumes that the instructions are in the same
endian configuration as the data, but when the CPU is running in
BE8 the instructions stay in little-endian format.

Make sure if CONFIG_CPU_ENDIAN_BE8 is set that we do all the
alterations to the instructions taking in to account the LDR/STR
will be swapping the data endian-ness.

Since the code is only modifying a byte, we avoid dual-swapping
the data, and just change the bits we clear and ORR in.

Note, not tested against an actual bug, it looked wrong.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
---
 arch/arm/kernel/head.S |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 8bac553..56ddd47 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -594,8 +594,14 @@ __fixup_a_pv_table:
 #else
 	b	2f
 1:	ldr	ip, [r7, r3]
+#ifdef CONFIG_CPU_ENDIAN_BE8
+	@ in BE8, we load data in BE, but instructions still in LE
+	bic	ip, ip, #0xff000000
+	orr	ip, ip, r6, lsl#24
+#else
 	bic	ip, ip, #0x000000ff
 	orr	ip, ip, r6	@ mask in offset bits 31-24
+#endif
 	str	ip, [r7, r3]
 2:	cmp	r4, r5
 	ldrcc	r7, [r4], #4	@ use branch for delay slot
-- 
1.7.10.4

  parent reply	other threads:[~2013-06-19 12:36 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-19 12:36 Initial big-endian support series Ben Dooks
2013-06-19 12:36 ` [PATCH 01/10] ARM: fix ARCH_IXP4xx usage of ARCH_SUPPORTS_BIG_ENDIAN Ben Dooks
2013-06-19 17:30   ` Thomas Petazzoni
2013-06-20 11:07     ` Ben Dooks
2013-06-19 12:36 ` Ben Dooks [this message]
2013-06-19 17:33   ` [PATCH 02/10] ARM: fixup_pv_table bug when CPU_ENDIAN_BE8 Thomas Petazzoni
2013-06-20 10:54     ` Ben Dooks
2013-06-20 16:09       ` Thomas Petazzoni
2013-06-19 12:36 ` [PATCH 03/10] ARM: asm: Add ARM_BE8() assembly helper Ben Dooks
2013-06-19 12:36 ` [PATCH 04/10] ARM: set BE8 if LE in head code Ben Dooks
2013-06-19 12:36 ` [PATCH 05/10] ARM: pl01x debug code endian fix Ben Dooks
2013-06-19 12:36 ` [PATCH 06/10] ARM: twd: data " Ben Dooks
2013-06-19 12:36 ` [PATCH 07/10] ARM: smp_scu: data endian fixes Ben Dooks
2013-06-19 12:36 ` [PATCH 08/10] highbank: enable big-endian Ben Dooks
2013-06-19 12:36 ` [PATCH 09/10] mvebu: support running big-endian Ben Dooks
2013-06-19 12:36 ` [PATCH 10/10] vexpress: add big endian support Ben Dooks
2013-06-20 16:12 ` Initial big-endian support series Thomas Petazzoni
2013-06-27 17:16 ` Ben Dooks

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