Re: [PATCH v2] riscv: fix vdso build with lld

From: Palmer Dabbelt
Date: Tue Apr 21 2020 - 18:24:36 EST


On Wed, 15 Apr 2020 07:29:58 PDT (-0700), ilie.halip@xxxxxxxxx wrote:
When building with the LLVM linker this error occurrs:
LD arch/riscv/kernel/vdso/vdso-syms.o
ld.lld: error: no input files

This happens because the lld treats -R as an alias to -rpath, as opposed
to ld where -R means --just-symbols.

Use the long option name for compatibility between the two.

Link: https://github.com/ClangBuiltLinux/linux/issues/805
Reported-by: Dmitry Golovin <dima@xxxxxxxxxx>
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Signed-off-by: Ilie Halip <ilie.halip@xxxxxxxxx>

---
Changed in v2:
* a comment line dropped, another one slightly reworded
* added Nick's Reviewed-by
---
arch/riscv/kernel/vdso/Makefile | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
index 33b16f4212f7..a4ee3a0e7d20 100644
--- a/arch/riscv/kernel/vdso/Makefile
+++ b/arch/riscv/kernel/vdso/Makefile
@@ -33,15 +33,15 @@ $(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso) FORCE
$(call if_changed,vdsold)

# We also create a special relocatable object that should mirror the symbol
-# table and layout of the linked DSO. With ld -R we can then refer to
-# these symbols in the kernel code rather than hand-coded addresses.
+# table and layout of the linked DSO. With ld --just-symbols we can then
+# refer to these symbols in the kernel code rather than hand-coded addresses.

SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \
-Wl,--build-id -Wl,--hash-style=both
$(obj)/vdso-dummy.o: $(src)/vdso.lds $(obj)/rt_sigreturn.o FORCE
$(call if_changed,vdsold)

-LDFLAGS_vdso-syms.o := -r -R
+LDFLAGS_vdso-syms.o := -r --just-symbols
$(obj)/vdso-syms.o: $(obj)/vdso-dummy.o FORCE
$(call if_changed,ld)

Thanks, this is on fixes.