| Message ID | 20171016132440.38098-5-mark.rutland@arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | Cleanup instrumentation avoidance | expand |
On Mon, Oct 16, 2017 at 02:24:40PM +0100, Mark Rutland wrote: > The arm64 VDSO Makefile explicitly disables gcov; a practice we seem to > have inherited from other VDSO Makefiles. > > The arm64 VDSO is written entirely in assembly, so this is not > necessary. Further, if the VDSO were written in C it would be necessary > to disable all other instrumentation, and this alone would not be > sufficient. Evidently, I haven't looked hrough the history thoroughly enough. It turns out that this was deliberately added in commit: 543097843ca7c9ac ("arm64: build vdso without libgcov") ... this is necessary because we use the compiler to do the actual linking. That causes us to have -lgcov in the compilr flags, and the link can fail. Please ignore this patch for now. Thanks, Mark. > This patch remosves the redundant GCOV option for now. > > Cc: Catalin Marinas <catalin.marinas@arm.com> > Reported-by: Will Deacon <will.deacon@arm.com> > Signed-off-by: Mark Rutland <mark.rutland@arm.com> > --- > arch/arm64/kernel/vdso/Makefile | 3 --- > 1 file changed, 3 deletions(-) > > diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile > index 62c84f7cb01b..350190b749dd 100644 > --- a/arch/arm64/kernel/vdso/Makefile > +++ b/arch/arm64/kernel/vdso/Makefile > @@ -15,9 +15,6 @@ ccflags-y := -shared -fno-common -fno-builtin > ccflags-y += -nostdlib -Wl,-soname=linux-vdso.so.1 \ > $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) > > -# Disable gcov profiling for VDSO code > -GCOV_PROFILE := n > - > # Workaround for bare-metal (ELF) toolchains that neglect to pass -shared > # down to collect2, resulting in silent corruption of the vDSO image. > ccflags-y += -Wl,-shared > -- > 2.11.0 >
diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index 62c84f7cb01b..350190b749dd 100644 --- a/arch/arm64/kernel/vdso/Makefile +++ b/arch/arm64/kernel/vdso/Makefile @@ -15,9 +15,6 @@ ccflags-y := -shared -fno-common -fno-builtin ccflags-y += -nostdlib -Wl,-soname=linux-vdso.so.1 \ $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) -# Disable gcov profiling for VDSO code -GCOV_PROFILE := n - # Workaround for bare-metal (ELF) toolchains that neglect to pass -shared # down to collect2, resulting in silent corruption of the vDSO image. ccflags-y += -Wl,-shared
The arm64 VDSO Makefile explicitly disables gcov; a practice we seem to have inherited from other VDSO Makefiles. The arm64 VDSO is written entirely in assembly, so this is not necessary. Further, if the VDSO were written in C it would be necessary to disable all other instrumentation, and this alone would not be sufficient. This patch remosves the redundant GCOV option for now. Cc: Catalin Marinas <catalin.marinas@arm.com> Reported-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Mark Rutland <mark.rutland@arm.com> --- arch/arm64/kernel/vdso/Makefile | 3 --- 1 file changed, 3 deletions(-) -- 2.11.0