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| author | Arnd Bergmann <arnd@arndb.de> | 2022-04-04 11:52:31 +0200 |
|---|---|---|
| committer | Arnd Bergmann <arnd@arndb.de> | 2022-04-08 17:20:54 +0200 |
| commit | 5d6f52671e76ca2d55d74e676ac4c38ceb14a2d3 (patch) | |
| tree | 7eb2ac50db50a924718ae5bd99641f3e4879150d /arch/arm/mach-versatile | |
| parent | a3102fafdce6f150e5a46e1725bb1732f8953a01 (diff) | |
| download | linux-stable-5d6f52671e76ca2d55d74e676ac4c38ceb14a2d3.tar.gz linux-stable-5d6f52671e76ca2d55d74e676ac4c38ceb14a2d3.tar.bz2 linux-stable-5d6f52671e76ca2d55d74e676ac4c38ceb14a2d3.zip | |
ARM: rework endianess selection
Choosing big-endian vs little-endian kernels in Kconfig has not worked
correctly since the introduction of CONFIG_ARCH_MULTIPLATFORM a long
time ago.
The problems is that CONFIG_BIG_ENDIAN depends on
ARCH_SUPPORTS_BIG_ENDIAN, which can set by any one platform
in the config, but would actually have to be supported by all
of them.
This was mostly ok for ARMv6/ARMv7 builds, since these are BE8 and
tend to just work aside from problems in nonportable device drivers.
For ARMv4/v5 machines, CONFIG_BIG_ENDIAN and CONFIG_ARCH_MULTIPLATFORM
were never set together, so this was disabled on all those machines
except for IXP4xx.
As IXP4xx can now become part of ARCH_MULTIPLATFORM, it seems better to
formalize this logic: all ARMv4/v5 platforms get an explicit dependency
on being either big-endian (ixp4xx) or little-endian (the rest). We may
want to fix ixp4xx in the future to support both, but it does not work
in LE mode at the moment.
For the ARMv6/v7 platforms, there are two ways this could be handled
a) allow both modes only for platforms selecting
'ARCH_SUPPORTS_BIG_ENDIAN' today, but only LE mode for the
others, given that these were added intentionally at some
point.
b) allow both modes everwhere, given that it was already possible
to build that way by e.g. selecting ARCH_VIRT, and that the
list is not an accurate reflection of which platforms may or
may not work.
Out of these, I picked b) because it seemed slighly more logical
to me.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'arch/arm/mach-versatile')
| -rw-r--r-- | arch/arm/mach-versatile/Kconfig | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/arm/mach-versatile/Kconfig b/arch/arm/mach-versatile/Kconfig index 94b492c12e8d..2ef226194c3a 100644 --- a/arch/arm/mach-versatile/Kconfig +++ b/arch/arm/mach-versatile/Kconfig @@ -2,6 +2,7 @@ config ARCH_VERSATILE bool "ARM Ltd. Versatile family" depends on ARCH_MULTI_V5 + depends on CPU_LITTLE_ENDIAN select ARM_AMBA select ARM_TIMER_SP804 select ARM_VIC @@ -19,6 +20,7 @@ config ARCH_VERSATILE menuconfig ARCH_INTEGRATOR bool "ARM Ltd. Integrator family" depends on ARCH_MULTI_V4T || ARCH_MULTI_V5 || ARCH_MULTI_V6 + depends on CPU_LITTLE_ENDIAN || ARCH_MULTI_V6 select ARM_AMBA select CMA select DMA_CMA @@ -143,7 +145,7 @@ endif menuconfig ARCH_REALVIEW bool "ARM Ltd. RealView family" - depends on ARCH_MULTI_V5 || ARCH_MULTI_V6 || ARCH_MULTI_V7 + depends on (CPU_LITTLE_ENDIAN && ARCH_MULTI_V5) || ARCH_MULTI_V6 || ARCH_MULTI_V7 select ARM_AMBA select ARM_GIC select ARM_TIMER_SP804 @@ -247,7 +249,6 @@ endif menuconfig ARCH_VEXPRESS bool "ARM Ltd. Versatile Express family" depends on ARCH_MULTI_V7 - select ARCH_SUPPORTS_BIG_ENDIAN select ARM_AMBA select ARM_GIC select ARM_GLOBAL_TIMER |