| Message ID | 20190926214342.34608-3-vincenzo.frascino@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: vdso32: Address various issues | expand |
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 <will@kernel.org> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
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 <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 | 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 "$$TMP" -,$(2),$(3)) It's a shame that we have to duplicate the logic from scripts/Kbuild.include here. Is there a way to reuse those helpers by temporarily overriding things like CC and KBUILD_AFLAGS? If not, no bother, but thought I'd better ask. Will
On 10/1/19 2:26 PM, Will Deacon wrote: > On Thu, Sep 26, 2019 at 10:43:39PM +0100, Vincenzo Frascino wrote: >> As reported by Will Deacon, older versions of binutils that do not >> support certain types of memory barriers can cause build failure of the >> vdso32 library. >> >> Add a compilation time mechanism that detects if binutils supports those >> instructions and configure the kernel accordingly. >> >> Cc: Will Deacon <will@kernel.org> >> Cc: Catalin Marinas <catalin.marinas@arm.com> >> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> >> --- >> arch/arm64/include/asm/vdso/compat_barrier.h | 2 +- >> arch/arm64/kernel/vdso32/Makefile | 9 +++++++++ >> 2 files changed, 10 insertions(+), 1 deletion(-) >> >> diff --git a/arch/arm64/include/asm/vdso/compat_barrier.h b/arch/arm64/include/asm/vdso/compat_barrier.h >> index fb60a88b5ed4..3fd8fd6d8fc2 100644 >> --- a/arch/arm64/include/asm/vdso/compat_barrier.h >> +++ b/arch/arm64/include/asm/vdso/compat_barrier.h >> @@ -20,7 +20,7 @@ >> >> #define dmb(option) __asm__ __volatile__ ("dmb " #option : : : "memory") >> >> -#if __LINUX_ARM_ARCH__ >= 8 >> +#if __LINUX_ARM_ARCH__ >= 8 && defined(CONFIG_AS_DMB_ISHLD) >> #define aarch32_smp_mb() dmb(ish) >> #define aarch32_smp_rmb() dmb(ishld) >> #define aarch32_smp_wmb() dmb(ishst) >> diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile >> index 19e0d3115ffe..77aa61340374 100644 >> --- a/arch/arm64/kernel/vdso32/Makefile >> +++ b/arch/arm64/kernel/vdso32/Makefile >> @@ -15,6 +15,8 @@ cc32-disable-warning = $(call try-run,\ >> $(COMPATCC) -W$(strip $(1)) -c -x c /dev/null -o "$$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 >
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)) # 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
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 | 9 +++++++++ 2 files changed, 10 insertions(+), 1 deletion(-)