diff mbox series

[v3,4/4] MIPS: VDSO: Allow ld.lld to link the VDSO

Message ID 20200423171807.29713-4-natechancellor@gmail.com (mailing list archive)
State New, archived
Headers show
Series [v3,1/4] kbuild: add CONFIG_LD_IS_LLD | expand

Commit Message

Nathan Chancellor April 23, 2020, 5:18 p.m. UTC
Currently, when linking with ld.lld, this warning pops up:

    arch/mips/vdso/Makefile:70: MIPS VDSO requires binutils >= 2.25

CONFIG_LD_VERSION is set with scripts/ld-version.sh, which is specific
to GNU ld. It returns 0 for ld.lld so CONFIG_MIPS_LD_CAN_LINK_VDSO does
not set.

ld.lld has a completely different versioning scheme (as it follows
LLVM's versioning) and it does not have the issue mentioned in the
comment block so it should be allowed to link the VDSO.

With this patch, the VDSO successfully links and shows P_MIPS_PC32 in
vgettimeofday.o.

$ llvm-objdump -Dr arch/mips/vdso/vgettimeofday.o | grep R_MIPS_PC32
			00000024:  R_MIPS_PC32	_start
			000000b0:  R_MIPS_PC32	_start
			000002bc:  R_MIPS_PC32	_start
			0000036c:  R_MIPS_PC32	_start
			00000468:  R_MIPS_PC32	_start

Reported-by: Dmitry Golovin <dima@golovin.in>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/785
Link: https://github.com/llvm/llvm-project/commit/e364e2e9ce50c12eb2bf093560e1a1a8544d455a
---

v2 -> v3:

* No changes.

v1 -> v2:

* Move into Kconfig so that the warning does not happen.

 arch/mips/vdso/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/arch/mips/vdso/Kconfig b/arch/mips/vdso/Kconfig
index 36a52158d849b..7aec721398d59 100644
--- a/arch/mips/vdso/Kconfig
+++ b/arch/mips/vdso/Kconfig
@@ -12,7 +12,7 @@ 
 # the lack of relocations. As such, we disable the VDSO for microMIPS builds.
 
 config MIPS_LD_CAN_LINK_VDSO
-	def_bool LD_VERSION >= 225000000
+	def_bool LD_VERSION >= 225000000 || LD_IS_LLD
 
 config MIPS_DISABLE_VDSO
 	def_bool CPU_MICROMIPS || (!CPU_MIPSR6 && !MIPS_LD_CAN_LINK_VDSO)