arm64: avoid BUILD_BUG_ON() in alternative-macros
Nathan reports that the build fails when using clang and LTO: | In file included from kernel/bounds.c:10: | In file included from ./include/linux/page-flags.h:10: | In file included from ./include/linux/bug.h:5: | In file included from ./arch/arm64/include/asm/bug.h:26: | In file included from ./include/asm-generic/bug.h:5: | In file included from ./include/linux/compiler.h:248: | In file included from ./arch/arm64/include/asm/rwonce.h:11: | ./arch/arm64/include/asm/alternative-macros.h:224:2: error: call to undeclared function 'BUILD_BUG_ON'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] | BUILD_BUG_ON(feature >= ARM64_NCAPS); | ^ | ./arch/arm64/include/asm/alternative-macros.h:241:2: error: call to undeclared function 'BUILD_BUG_ON'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] | BUILD_BUG_ON(feature >= ARM64_NCAPS); | ^ | 2 errors generated. ... the problem being that when LTO is enabled, <asm/rwonce.h> includes <asm/alternative-macros.h>, and causes a circular include dependency through <linux/bug.h>. This manifests as BUILD_BUG_ON() not being defined when used within <asm/alternative-macros.h>. This patch avoids the problem and simplifies the include dependencies by using compiletime_assert() instead of BUILD_BUG_ON(). Signed-off-by: Mark Rutland <mark.rutland@arm.com> Fixes: 21fb26bf ("arm64: alternatives: add alternative_has_feature_*()") Reported-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Link: http://lore.kernel.org/r/YyigTrxhE3IRPzjs@dev-arch.thelio-3990X Cc: Ard Biesheuvel <ardb@kernel.org> Cc: James Morse <james.morse@arm.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Will Deacon <will@kernel.org> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220920140044.1709073-1-mark.rutland@arm.comSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>
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