Messages in this thread | | | Date | Tue, 5 May 2020 15:25:56 +0100 | From | Mark Rutland <> | Subject | Re: [PATCH] arm64: disable patchable function entry on big-endian clang builds |
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On Tue, May 05, 2020 at 04:12:36PM +0200, Arnd Bergmann wrote: > Clang only supports the patchable_function_entry attribute on > little-endian arm64 builds, but not on big-endian: > > include/linux/kasan-checks.h:16:8: error: unknown attribute 'patchable_function_entry' ignored [-Werror,-Wunknown-attributes] > > Disable that configuration with another dependency. Unfortunately > the existing check is not enough, as $(cc-option) at this point does > not pass the -mbig-endian flag.
Well that's unfortunate. :(
Do we know if this is deliberate and/or likely to change in future? This practically rules out a BE distro kernel with things like PAC, which isn't ideal.
> Fixes: 3b23e4991fb6 ("arm64: implement ftrace with regs") > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This looks fine for now, and we can add a version check in future, so:
Acked-by: Mark Rutland <mark.rutland@arm.com>
Mark.
> --- > arch/arm64/Kconfig | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 4b256fa6db7a..a33d6402b934 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -151,7 +151,7 @@ config ARM64 > select HAVE_DMA_CONTIGUOUS > select HAVE_DYNAMIC_FTRACE > select HAVE_DYNAMIC_FTRACE_WITH_REGS \ > - if $(cc-option,-fpatchable-function-entry=2) > + if $(cc-option,-fpatchable-function-entry=2) && !(CC_IS_CLANG && CPU_BIG_ENDIAN) > select HAVE_EFFICIENT_UNALIGNED_ACCESS > select HAVE_FAST_GUP > select HAVE_FTRACE_MCOUNT_RECORD > -- > 2.26.0 >
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