Messages in this thread Patch in this message | | | From | Matthias Kaehlcke <> | Date | Fri, 15 Mar 2019 12:54:13 -0700 | Subject | [PATCH] x86/vdso: include generic __lshrdi3 in 32-bit vDSO |
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Building the 32-bit vDSO with a recent clang version fails due to undefined symbols:
arch/x86/entry/vdso/vdso32.so.dbg: undefined symbols found
The undefined symbol in this case is __lshrdi3, which is part of the compiler runtime library, however the vDSO isn't linked against this library.
Include the kernel version of __lshrdi3 in the 32-bit vDSO build.
Signed-off-by: Matthias Kaehlcke <mka@chromium.org> --- arch/x86/entry/vdso/Makefile | 7 ++++++- lib/lshrdi3.c | 4 +++- 2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index 5bfe2243a08f..7517cd87e10b 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -144,6 +144,7 @@ KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector) KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls) KBUILD_CFLAGS_32 += -fno-omit-frame-pointer KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING +KBUILD_CFLAGS_32 += -DBUILD_VDSO
ifdef CONFIG_RETPOLINE ifneq ($(RETPOLINE_VDSO_CFLAGS),) @@ -153,12 +154,16 @@ endif
$(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
+$(obj)/vdso32/lshrdi3.o: $(srctree)/lib/lshrdi3.c FORCE + $(call if_changed_rule,cc_o_c) + $(obj)/vdso32.so.dbg: FORCE \ $(obj)/vdso32/vdso32.lds \ $(obj)/vdso32/vclock_gettime.o \ $(obj)/vdso32/note.o \ $(obj)/vdso32/system_call.o \ - $(obj)/vdso32/sigreturn.o + $(obj)/vdso32/sigreturn.o \ + $(obj)/vdso32/lshrdi3.o $(call if_changed,vdso)
# diff --git a/lib/lshrdi3.c b/lib/lshrdi3.c index 99cfa5721f2d..8a4fc6bcf3a4 100644 --- a/lib/lshrdi3.c +++ b/lib/lshrdi3.c @@ -16,7 +16,7 @@ * to the Free Software Foundation, Inc. */
-#include <linux/module.h> +#include <linux/export.h> #include <linux/libgcc.h>
long long notrace __lshrdi3(long long u, word_type b) @@ -42,4 +42,6 @@ long long notrace __lshrdi3(long long u, word_type b)
return w.ll; } +#ifndef BUILD_VDSO EXPORT_SYMBOL(__lshrdi3); +#endif -- 2.21.0.360.g471c308f928-goog
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