| From e4fc12c4e5d5e763c4a93a285dc926d1944f1562 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Thu, 3 Oct 2019 18:48:34 +0100 |
| Subject: arm64: vdso32: Detect binutils support for dmb ishld |
| |
| From: Vincenzo Frascino <vincenzo.frascino@arm.com> |
| |
| [ Upstream commit 0df2c90eba60791148cee1823c0bf5fc66e3465c ] |
| |
| Older versions of binutils (prior to 2.24) do not support the "ISHLD" |
| option for memory barrier instructions, which leads to a build failure |
| when assembling 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> |
| Reported-by: Will Deacon <will@kernel.org> |
| Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> |
| Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> |
| Tested-by: Catalin Marinas <catalin.marinas@arm.com> |
| Signed-off-by: Will Deacon <will@kernel.org> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| 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 fb60a88b5ed41..3fd8fd6d8fc25 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 19e0d3115ffe0..77aa613403747 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)) |
| |
| # We cannot use the global flags to compile the vDSO files, the main reason |
| # being that the 32-bit compiler may be older than the main (64-bit) compiler |
| @@ -53,6 +55,7 @@ endif |
| VDSO_CAFLAGS += -fPIC -fno-builtin -fno-stack-protector |
| VDSO_CAFLAGS += -DDISABLE_BRANCH_PROFILING |
| |
| + |
| # 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). |
| @@ -89,6 +92,12 @@ VDSO_CFLAGS += -Wno-int-to-pointer-cast |
| VDSO_AFLAGS := $(VDSO_CAFLAGS) |
| VDSO_AFLAGS += -D__ASSEMBLY__ |
| |
| +# Check for binutils support for dmb ishld |
| +dmbinstr := $(call cc32-as-instr,dmb ishld,-DCONFIG_AS_DMB_ISHLD=1) |
| + |
| +VDSO_CFLAGS += $(dmbinstr) |
| +VDSO_AFLAGS += $(dmbinstr) |
| + |
| VDSO_LDFLAGS := $(VDSO_CPPFLAGS) |
| # From arm vDSO Makefile |
| VDSO_LDFLAGS += -Wl,-Bsymbolic -Wl,--no-undefined -Wl,-soname=linux-vdso.so.1 |
| -- |
| 2.20.1 |
| |