From: ben.dooks@codethink.co.uk (Ben Dooks)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/9] ARM: fixup_pv_table bug when CPU_ENDIAN_BE8
Date: Wed, 13 Feb 2013 10:55:20 +0000 [thread overview]
Message-ID: <1360752927-29331-3-git-send-email-ben.dooks@codethink.co.uk> (raw)
In-Reply-To: <1360752927-29331-1-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 486a15a..cc15384 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -576,8 +576,14 @@ __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
next prev parent reply other threads:[~2013-02-13 10:55 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-13 10:55 [RFC v3] Better BE support for ARM Ben Dooks
2013-02-13 10:55 ` [PATCH 1/9] ARM: fix ARCH_IXP4xx usage of ARCH_SUPPORTS_BIG_ENDIAN Ben Dooks
2013-02-18 19:58 ` Krzysztof Halasa
2013-02-13 10:55 ` Ben Dooks [this message]
2013-02-19 12:04 ` [PATCH 2/9] ARM: fixup_pv_table bug when CPU_ENDIAN_BE8 Dave Martin
2013-02-13 10:55 ` [PATCH 3/9] ARM: asm: Add ARM_BE8() assembly helper Ben Dooks
2013-02-14 4:27 ` Nicolas Pitre
2013-02-19 12:07 ` Dave Martin
2013-02-13 10:55 ` [PATCH 4/9] ARM: set BE8 if LE in head code Ben Dooks
2013-02-14 4:33 ` Nicolas Pitre
2013-02-13 10:55 ` [PATCH 5/9] ARM: pl01x debug code endian fix Ben Dooks
2013-02-19 12:27 ` Dave Martin
2013-02-13 10:55 ` [PATCH 6/9] ARM: twd: data " Ben Dooks
2013-02-13 10:55 ` [PATCH 7/9] ARM: smp_scu: data endian fixes Ben Dooks
2013-02-13 10:55 ` [PATCH 8/9] highbank: enable big-endian Ben Dooks
2013-02-13 10:55 ` [PATCH 9/9] mvebu: support running big-endian Ben Dooks
2013-02-15 11:39 ` [RFC v3] Better BE support for ARM Ben Dooks
2013-02-19 12:00 ` Dave Martin
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