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| author | Tom Rini <trini@ti.com> | 2014-02-25 10:27:01 -0500 |
|---|---|---|
| committer | Albert ARIBAUD <albert.u.boot@aribaud.net> | 2014-02-26 21:19:32 +0100 |
| commit | 1551df35f296f0a8df32f4f2054254f46e8be252 (patch) | |
| tree | 5c93d004be051b5b3cfae8c5cbdf297f8b07bb9b /arch/arm/cpu | |
| parent | f503cc49a570b1e28a93b75bc912aedc93ba2cd0 (diff) | |
| download | u-boot-imx-1551df35f296f0a8df32f4f2054254f46e8be252.zip u-boot-imx-1551df35f296f0a8df32f4f2054254f46e8be252.tar.gz u-boot-imx-1551df35f296f0a8df32f4f2054254f46e8be252.tar.bz2 | |
arm: Switch to -mno-unaligned-access when supported by the compiler
When we tell the compiler to optimize for ARMv7 (and ARMv6 for that
matter) it assumes a default of SCTRL.A being cleared and unaligned
accesses being allowed and fast at the hardware level. We set this bit
and must pass along -mno-unaligned-access so that the compiler will
still breakdown accesses and not trigger a data abort.
To better help understand the requirements of the project with respect
to unaligned memory access, the
Documentation/unaligned-memory-access.txt file has been added as
doc/README.unaligned-memory-access.txt and is taken from the v3.14-rc1
tag of the kernel.
Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
Cc: Mans Rullgard <mans@mansr.com>
Signed-off-by: Tom Rini <trini@ti.com>
Diffstat (limited to 'arch/arm/cpu')
| -rw-r--r-- | arch/arm/cpu/armv7/config.mk | 7 | ||||
| -rw-r--r-- | arch/arm/cpu/armv8/config.mk | 5 |
2 files changed, 6 insertions, 6 deletions
diff --git a/arch/arm/cpu/armv7/config.mk b/arch/arm/cpu/armv7/config.mk index d01f3d9..c048531 100644 --- a/arch/arm/cpu/armv7/config.mk +++ b/arch/arm/cpu/armv7/config.mk @@ -10,9 +10,12 @@ PF_CPPFLAGS_ARMV7 := $(call cc-option, -march=armv7-a, -march=armv5) PLATFORM_CPPFLAGS += $(PF_CPPFLAGS_ARMV7) -# SEE README.arm-unaligned-accesses +# On supported platforms we set the bit which causes us to trap on unaligned +# memory access. This is the opposite of what the compiler expects to be +# the default so we must pass in -mno-unaligned-access so that it is aware +# of our decision. PF_NO_UNALIGNED := $(call cc-option, -mno-unaligned-access,) -PLATFORM_NO_UNALIGNED := $(PF_NO_UNALIGNED) +PLATFORM_CPPFLAGS += $(PF_NO_UNALIGNED) ifneq ($(CONFIG_IMX_CONFIG),) ifdef CONFIG_SPL diff --git a/arch/arm/cpu/armv8/config.mk b/arch/arm/cpu/armv8/config.mk index 027a68c..f5b9559 100644 --- a/arch/arm/cpu/armv8/config.mk +++ b/arch/arm/cpu/armv8/config.mk @@ -6,10 +6,7 @@ # PLATFORM_RELFLAGS += -fno-common -ffixed-x18 -# SEE README.arm-unaligned-accesses -PF_NO_UNALIGNED := $(call cc-option, -mstrict-align) -PLATFORM_NO_UNALIGNED := $(PF_NO_UNALIGNED) - PF_CPPFLAGS_ARMV8 := $(call cc-option, -march=armv8-a) +PF_NO_UNALIGNED := $(call cc-option, -mstrict-align) PLATFORM_CPPFLAGS += $(PF_CPPFLAGS_ARMV8) PLATFORM_CPPFLAGS += $(PF_NO_UNALIGNED) |