| Message ID | 20220920140044.1709073-1-mark.rutland@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: avoid BUILD_BUG_ON() in alternative-macros | expand |
On Tue, 20 Sept 2022 at 16:00, Mark Rutland <mark.rutland@arm.com> wrote: > > 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: 21fb26bfb01ffe0d ("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: Catalin Marinas <catalin.marinas@arm.com> > 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> > --- > arch/arm64/include/asm/alternative-macros.h | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/include/asm/alternative-macros.h b/arch/arm64/include/asm/alternative-macros.h > index 4a2a98d6d2227..966767debaa3a 100644 > --- a/arch/arm64/include/asm/alternative-macros.h > +++ b/arch/arm64/include/asm/alternative-macros.h > @@ -215,13 +215,13 @@ alternative_endif > > #ifndef __ASSEMBLY__ > > -#include <linux/bug.h> > #include <linux/types.h> > > static __always_inline bool > alternative_has_feature_likely(unsigned long feature) > { > - BUILD_BUG_ON(feature >= ARM64_NCAPS); > + compiletime_assert(feature < ARM64_NCAPS, > + "feature must be < ARM64_NCAPS"); > > asm_volatile_goto( > ALTERNATIVE_CB("b %l[l_no]", %[feature], alt_cb_patch_nops) > @@ -238,7 +238,8 @@ alternative_has_feature_likely(unsigned long feature) > static __always_inline bool > alternative_has_feature_unlikely(unsigned long feature) > { > - BUILD_BUG_ON(feature >= ARM64_NCAPS); > + compiletime_assert(feature < ARM64_NCAPS, > + "feature must be < ARM64_NCAPS"); > > asm_volatile_goto( > ALTERNATIVE("nop", "b %l[l_yes]", %[feature]) > -- > 2.30.2 >
On Tue, 20 Sep 2022 15:00:44 +0100, Mark Rutland <mark.rutland@arm.com> wrote: > > 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: 21fb26bfb01ffe0d ("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: Catalin Marinas <catalin.marinas@arm.com> > 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> > --- > arch/arm64/include/asm/alternative-macros.h | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) Acked-by: Marc Zyngier <maz@kernel.org> M.
On Tue, 20 Sep 2022 15:00:44 +0100, Mark Rutland wrote: > 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. > > [...] Applied to arm64 (for-next/alternatives), thanks! [1/1] arm64: avoid BUILD_BUG_ON() in alternative-macros https://git.kernel.org/arm64/c/0072dc1b53c3
diff --git a/arch/arm64/include/asm/alternative-macros.h b/arch/arm64/include/asm/alternative-macros.h index 4a2a98d6d2227..966767debaa3a 100644 --- a/arch/arm64/include/asm/alternative-macros.h +++ b/arch/arm64/include/asm/alternative-macros.h @@ -215,13 +215,13 @@ alternative_endif #ifndef __ASSEMBLY__ -#include <linux/bug.h> #include <linux/types.h> static __always_inline bool alternative_has_feature_likely(unsigned long feature) { - BUILD_BUG_ON(feature >= ARM64_NCAPS); + compiletime_assert(feature < ARM64_NCAPS, + "feature must be < ARM64_NCAPS"); asm_volatile_goto( ALTERNATIVE_CB("b %l[l_no]", %[feature], alt_cb_patch_nops) @@ -238,7 +238,8 @@ alternative_has_feature_likely(unsigned long feature) static __always_inline bool alternative_has_feature_unlikely(unsigned long feature) { - BUILD_BUG_ON(feature >= ARM64_NCAPS); + compiletime_assert(feature < ARM64_NCAPS, + "feature must be < ARM64_NCAPS"); asm_volatile_goto( ALTERNATIVE("nop", "b %l[l_yes]", %[feature])