[PATCH v2] riscv: fix vdso build with lld

[PATCH v2] riscv: fix vdso build with lld

[Ilie Halip]

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@golovin.in>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Ilie Halip <ilie.halip@gmail.com>

---
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)
 
-- 
2.17.1

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

[Fangrui Song]

On 2020-04-15, Ilie Halip 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@golovin.in>
>Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
>Signed-off-by: Ilie Halip <ilie.halip@gmail.com>
>
>---
>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)
>
>-- 
>2.17.1

https://lore.kernel.org/linux-riscv/20200402175354.pzhzhumlqsjk66nu@google.com/

Reviewed-by: Fangrui Song <maskray@google.com>

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

[Palmer Dabbelt]

On Wed, 15 Apr 2020 07:29:58 PDT (-0700), ilie.halip@gmail.com 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@golovin.in>
> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Ilie Halip <ilie.halip@gmail.com>
>
> ---
> 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.