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. Will
