| Message ID | 20190411092933.6413-1-yamada.masahiro@socionext.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | ARM: vdso: use $(LD) instead of $(CC) to link VDSO | expand |
On Thu, Apr 11, 2019 at 2:30 AM Masahiro Yamada <yamada.masahiro@socionext.com> wrote: > My plan is to rewrite all VDSO Makefiles to use $(LD), then delete > cc-ldoption. I too look forward to the removal of cc-ldoption. Thanks for the patch. Based on some of the discussion in a similar patch for aarch64: https://lkml.org/lkml/2019/4/12/760: Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > --- > > arch/arm/vdso/Makefile | 21 ++++++++------------- > 1 file changed, 8 insertions(+), 13 deletions(-) > > diff --git a/arch/arm/vdso/Makefile b/arch/arm/vdso/Makefile > index f4efff9d3afb..fadf554d9391 100644 > --- a/arch/arm/vdso/Makefile > +++ b/arch/arm/vdso/Makefile > @@ -10,12 +10,12 @@ obj-vdso := $(addprefix $(obj)/, $(obj-vdso)) > ccflags-y := -fPIC -fno-common -fno-builtin -fno-stack-protector > ccflags-y += -DDISABLE_BRANCH_PROFILING > > -VDSO_LDFLAGS := -Wl,-Bsymbolic -Wl,--no-undefined -Wl,-soname=linux-vdso.so.1 > -VDSO_LDFLAGS += -Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096 > -VDSO_LDFLAGS += -nostdlib -shared > -VDSO_LDFLAGS += $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) > -VDSO_LDFLAGS += $(call cc-ldoption, -Wl$(comma)--build-id) > -VDSO_LDFLAGS += $(call cc-ldoption, -fuse-ld=bfd) > +ldflags-y = -Bsymbolic --no-undefined -soname=linux-vdso.so.1 \ > + -z max-page-size=4096 -z common-page-size=4096 \ This reminds me that I should resend: https://lore.kernel.org/patchwork/patch/1023578/ -- Thanks, ~Nick Desaulniers
diff --git a/arch/arm/vdso/Makefile b/arch/arm/vdso/Makefile index f4efff9d3afb..fadf554d9391 100644 --- a/arch/arm/vdso/Makefile +++ b/arch/arm/vdso/Makefile @@ -10,12 +10,12 @@ obj-vdso := $(addprefix $(obj)/, $(obj-vdso)) ccflags-y := -fPIC -fno-common -fno-builtin -fno-stack-protector ccflags-y += -DDISABLE_BRANCH_PROFILING -VDSO_LDFLAGS := -Wl,-Bsymbolic -Wl,--no-undefined -Wl,-soname=linux-vdso.so.1 -VDSO_LDFLAGS += -Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096 -VDSO_LDFLAGS += -nostdlib -shared -VDSO_LDFLAGS += $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) -VDSO_LDFLAGS += $(call cc-ldoption, -Wl$(comma)--build-id) -VDSO_LDFLAGS += $(call cc-ldoption, -fuse-ld=bfd) +ldflags-y = -Bsymbolic --no-undefined -soname=linux-vdso.so.1 \ + -z max-page-size=4096 -z common-page-size=4096 \ + -nostdlib -shared \ + $(call ld-option, --hash-style=sysv) \ + $(call ld-option, --build-id) \ + -T obj-$(CONFIG_VDSO) += vdso.o extra-$(CONFIG_VDSO) += vdso.lds @@ -37,8 +37,8 @@ KCOV_INSTRUMENT := n $(obj)/vdso.o : $(obj)/vdso.so # Link rule for the .so file -$(obj)/vdso.so.raw: $(src)/vdso.lds $(obj-vdso) FORCE - $(call if_changed,vdsold) +$(obj)/vdso.so.raw: $(obj)/vdso.lds $(obj-vdso) FORCE + $(call if_changed,ld) $(obj)/vdso.so.dbg: $(obj)/vdso.so.raw $(obj)/vdsomunge FORCE $(call if_changed,vdsomunge) @@ -48,11 +48,6 @@ $(obj)/%.so: OBJCOPYFLAGS := -S $(obj)/%.so: $(obj)/%.so.dbg FORCE $(call if_changed,objcopy) -# Actual build commands -quiet_cmd_vdsold = VDSO $@ - cmd_vdsold = $(CC) $(c_flags) $(VDSO_LDFLAGS) \ - -Wl,-T $(filter %.lds,$^) $(filter %.o,$^) -o $@ - quiet_cmd_vdsomunge = MUNGE $@ cmd_vdsomunge = $(objtree)/$(obj)/vdsomunge $< $@
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 confirmed the same vdso.so.raw was still produced. 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.masahiro@socionext.com> --- arch/arm/vdso/Makefile | 21 ++++++++------------- 1 file changed, 8 insertions(+), 13 deletions(-) -- 2.17.1