From: Andrey Smirnov <andrew.smirnov@gmail.com>
To: barebox@lists.infradead.org
Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Subject: [PATCH 2/8] arm: Disable unaligned accesses
Date: Sun, 11 Oct 2015 11:43:35 -0700 [thread overview]
Message-ID: <1444589021-12727-2-git-send-email-andrew.smirnov@gmail.com> (raw)
In-Reply-To: <1444589021-12727-1-git-send-email-andrew.smirnov@gmail.com>
Form reading ARM architecture related documentation if appears that
while unaligned memory access is supported by the processor in general
it is not supported if MMU is disabled.
The problem in question can be easilty reproduced by building the code
without this patch, MMU disabled, and trying to run 'memtest'
command. Which would in turn call mem_test() which would eventually
call show_progress(). That last function, if build without
-mno-unaligned-access would result in unaligned memory access which
would result in Barebox hanging.
This patch instructs the compiler to not generate any unaligned
accesses to memory thus avoiding the problem.
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
---
arch/arm/Makefile | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 721aa9b..cae05ff 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -13,6 +13,13 @@ AS += -EL
LD += -EL
endif
+# Unaligned access is not supported when MMU is disabled, so given how
+# at least some of the code would be executed with MMU off, lets be
+# conservative and instruct the compiler not to generate any unaligned
+# accesses
+CFLAGS += -mno-unaligned-access
+
+
# This selects which instruction set is used.
# Note that GCC does not numerically define an architecture version
# macro, but instead defines a whole series of macros which makes
--
2.1.4
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next prev parent reply other threads:[~2015-10-11 18:44 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-11 18:43 [PATCH 1/8] memtest.c: Print iterations count if -i is 0 Andrey Smirnov
2015-10-11 18:43 ` Andrey Smirnov [this message]
2015-10-11 18:43 ` [PATCH 3/8] arm/cpu/start.c: Distil some common code in __start() Andrey Smirnov
2015-10-12 9:44 ` Sascha Hauer
2015-10-11 18:43 ` [PATCH 4/8] arm/cpu: Avoid multiple definitions of barebox_arm_entry Andrey Smirnov
2015-10-12 9:37 ` Sascha Hauer
2015-10-11 18:43 ` [PATCH 5/8] freescale-mx6-sabresd: Add CONFIG_DEBUG_LL support Andrey Smirnov
2015-10-11 18:43 ` [PATCH 6/8] common/command.c: Replace magic number with appropriate constant Andrey Smirnov
2015-10-11 18:43 ` [PATCH 7/8] common/parser.c: Do not conflate error reporting disciplines Andrey Smirnov
2015-10-11 18:43 ` [PATCH 8/8] common/parser.c: Do not treat zero return code as error Andrey Smirnov
2015-10-12 9:46 ` [PATCH 1/8] memtest.c: Print iterations count if -i is 0 Sascha Hauer
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