Messages in this thread Patch in this message | | | From | Vincenzo Frascino <> | Subject | [PATCH 2/4] arm64: vdso32: Detect binutils support for dmb ishld | Date | Thu, 26 Sep 2019 07:03:51 +0100 |
| |
As reported by Will Deacon, older versions of binutils that do not support certain types of memory barriers can cause build failure of the vdso32 library.
Add a compilation time mechanism that detects if binutils supports those instructions and configure the kernel accordingly.
Cc: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> --- arch/arm64/include/asm/vdso/compat_barrier.h | 2 +- arch/arm64/kernel/vdso32/Makefile | 5 ++++- 2 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/vdso/compat_barrier.h b/arch/arm64/include/asm/vdso/compat_barrier.h index fb60a88b5ed4..3fd8fd6d8fc2 100644 --- a/arch/arm64/include/asm/vdso/compat_barrier.h +++ b/arch/arm64/include/asm/vdso/compat_barrier.h @@ -20,7 +20,7 @@ #define dmb(option) __asm__ __volatile__ ("dmb " #option : : : "memory") -#if __LINUX_ARM_ARCH__ >= 8 +#if __LINUX_ARM_ARCH__ >= 8 && defined(CONFIG_AS_DMB_ISHLD) #define aarch32_smp_mb() dmb(ish) #define aarch32_smp_rmb() dmb(ishld) #define aarch32_smp_wmb() dmb(ishst) diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile index 1fba0776ed40..1a3299d901b1 100644 --- a/arch/arm64/kernel/vdso32/Makefile +++ b/arch/arm64/kernel/vdso32/Makefile @@ -55,6 +55,9 @@ endif VDSO_CAFLAGS += -fPIC -fno-builtin -fno-stack-protector VDSO_CAFLAGS += -DDISABLE_BRANCH_PROFILING +# Check for binutils support for dmb ishld +dmbinstr := $(call as-instr,dmb ishld,-DCONFIG_AS_DMB_ISHLD=1) + # Try to compile for ARMv8. If the compiler is too old and doesn't support it, # fall back to v7. There is no easy way to check for what architecture the code # is being compiled, so define a macro specifying that (see arch/arm/Makefile). @@ -62,7 +65,7 @@ VDSO_CAFLAGS += $(call cc32-option,-march=armv8-a -D__LINUX_ARM_ARCH__=8,\ -march=armv7-a -D__LINUX_ARM_ARCH__=7) VDSO_CFLAGS := $(VDSO_CAFLAGS) -VDSO_CFLAGS += -DENABLE_COMPAT_VDSO=1 +VDSO_CFLAGS += -DENABLE_COMPAT_VDSO=1 $(dmbinstr) # KBUILD_CFLAGS from top-level Makefile VDSO_CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \ -fno-strict-aliasing -fno-common \ -- 2.23.0
| |