On Thu, Apr 11, 2019 at 2:30 AM Masahiro Yamada <yamada.masah...@socionext.com> wrote: > > We use $(LD) to link vmlinux, modules, decompressors, etc. > > VDSO is the only exceptional case where $(CC) is used as the linker > driver, but I do not know why we need to do so. VDSO uses a special > linker script, and does not link standard libraries at all. > > I changed the Makefile to use $(LD) rather than $(CC). I tested this, > and VDSO worked for me. > > Users will be able to use their favorite linker (e.g. lld instead of > of bfd) by passing LD= from the command line. > > My plan is to rewrite all VDSO Makefiles to use $(LD), then delete > cc-ldoption. > > Signed-off-by: Masahiro Yamada <yamada.masah...@socionext.com> > --- > > arch/arm64/kernel/vdso/Makefile | 13 +++---------- > 1 file changed, 3 insertions(+), 10 deletions(-) > > diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile > index a0af6bf6c11b..744b9dbaba03 100644 > --- a/arch/arm64/kernel/vdso/Makefile > +++ b/arch/arm64/kernel/vdso/Makefile > @@ -12,17 +12,12 @@ obj-vdso := gettimeofday.o note.o sigreturn.o > targets := $(obj-vdso) vdso.so vdso.so.dbg > obj-vdso := $(addprefix $(obj)/, $(obj-vdso)) > > -ccflags-y := -shared -fno-common -fno-builtin
Thanks for the patch; in general LGTM. Just some small questions: Looks like -shared and -fno-common are linker flags forwarded along, but -fno-builtin is meant for the compiler, right? Do we want to keep that in ccflags? I'm not sure why it would have been added intentionally; maybe Will knows? Maybe it's ok to drop. > -ccflags-y += -nostdlib -Wl,-soname=linux-vdso.so.1 \ > - $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) > +ldflags-y := -shared -nostdlib -soname=linux-vdso.so.1 \ > + $(call ld-option, --hash-style=sysv) -n -T Forgive my ignorance, but the man page for ld makes it looks like the -T argument requires a subsequent argument `scriptfile`. Is that what `$(real-prereqs)` was doing below? If so, is dropping it in this patch intentional? > > # 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 > - > obj-y += vdso.o > extra-y += vdso.lds > CPPFLAGS_vdso.lds += -P -C -U$(ARCH) > @@ -32,7 +27,7 @@ $(obj)/vdso.o : $(obj)/vdso.so > > # Link rule for the .so file, .lds has to be first > $(obj)/vdso.so.dbg: $(obj)/vdso.lds $(obj-vdso) FORCE > - $(call if_changed,vdsold) > + $(call if_changed,ld) > > # Strip rule for the .so file > $(obj)/%.so: OBJCOPYFLAGS := -S > @@ -52,8 +47,6 @@ $(obj-vdso): %.o: %.S FORCE > $(call if_changed_dep,vdsoas) > > # Actual build commands > -quiet_cmd_vdsold = VDSOL $@ > - cmd_vdsold = $(CC) $(c_flags) -Wl,-n -Wl,-T $(real-prereqs) -o $@ > quiet_cmd_vdsoas = VDSOA $@ > cmd_vdsoas = $(CC) $(a_flags) -c -o $@ $< > > -- > 2.17.1 > -- Thanks, ~Nick Desaulniers
