On 10/1/19 2:26 PM, Will Deacon wrote: > On Thu, Sep 26, 2019 at 10:43:39PM +0100, Vincenzo Frascino wrote: >> 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 <[email protected]> >> Cc: Catalin Marinas <[email protected]> >> Signed-off-by: Vincenzo Frascino <[email protected]> >> --- >> arch/arm64/include/asm/vdso/compat_barrier.h | 2 +- >> arch/arm64/kernel/vdso32/Makefile | 9 +++++++++ >> 2 files changed, 10 insertions(+), 1 deletion(-) >> >> 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 19e0d3115ffe..77aa61340374 100644 >> --- a/arch/arm64/kernel/vdso32/Makefile >> +++ b/arch/arm64/kernel/vdso32/Makefile >> @@ -15,6 +15,8 @@ cc32-disable-warning = $(call try-run,\ >> $(COMPATCC) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip >> $(1))) >> cc32-ldoption = $(call try-run,\ >> $(COMPATCC) $(1) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2)) >> +cc32-as-instr = $(call try-run,\ >> + printf "%b\n" "$(1)" | $(COMPATCC) $(VDSO_AFLAGS) -c -x assembler -o >> "$$TMP" -,$(2),$(3)) > > It's a shame that we have to duplicate the logic from scripts/Kbuild.include > here. Is there a way to reuse those helpers by temporarily overriding things > like CC and KBUILD_AFLAGS? If not, no bother, but thought I'd better ask. >
I tried to define a rule in scripts/Kbuild.include at the beginning doing what you are saying but I could not end up with a working solution, hence I ended up with a dedicated one. > Will > -- Regards, Vincenzo
