From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3/3] ARM: nommu: do not enable DCACHE_WORD_ACCESS when !CONFIG_MMU
Date: Mon, 3 Dec 2012 17:56:43 +0000 [thread overview]
Message-ID: <1354557403-20386-3-git-send-email-will.deacon@arm.com> (raw)
In-Reply-To: <1354557403-20386-1-git-send-email-will.deacon@arm.com>
Commit b9a50f74905a ("ARM: 7450/1: dcache: select DCACHE_WORD_ACCESS for
little-endian ARMv6+ CPUs") added support for word-at-time path
comparisons, relying on the ability to perform unaligned loads with
negligible performance impact in hardware.
For nommu configurations without MPU support, this is unpredictable and
so we should fall back to the byte-by-byte routines.
Signed-off-by: Will Deacon <will.deacon@arm.com>
---
arch/arm/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index ade7e92..3388431 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -6,7 +6,7 @@ config ARM
select ARCH_HAVE_CUSTOM_GPIO_H
select ARCH_WANT_IPC_PARSE_VERSION
select CPU_PM if (SUSPEND || CPU_IDLE)
- select DCACHE_WORD_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && !CPU_BIG_ENDIAN
+ select DCACHE_WORD_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && !CPU_BIG_ENDIAN && MMU
select GENERIC_ATOMIC64 if (CPU_V6 || !CPU_32v6K || !AEABI)
select GENERIC_CLOCKEVENTS_BROADCAST if SMP
select GENERIC_IRQ_PROBE
--
1.8.0
next prev parent reply other threads:[~2012-12-03 17:56 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-03 17:56 [PATCH 1/3] ARM: nommu: allow unaligned accesses on ARMv6+ processors Will Deacon
2012-12-03 17:56 ` [PATCH 2/3] ARM: nommu: prevent generation of kernel unaligned memory accesses Will Deacon
2012-12-03 18:55 ` Rob Herring
2012-12-03 19:27 ` Nicolas Pitre
2012-12-03 17:56 ` Will Deacon [this message]
2012-12-03 18:20 ` [PATCH 1/3] ARM: nommu: allow unaligned accesses on ARMv6+ processors Jonathan Austin
2012-12-03 19:25 ` Nicolas Pitre
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