Commit-ID: f24f910884277aa6824bbc2dda4b5d0418d45c28
Gitweb: http://git.kernel.org/tip/f24f910884277aa6824bbc2dda4b5d0418d45c28
Author: Andy Lutomirski <luto@xxxxxxxxxx>
AuthorDate: Mon, 5 Oct 2015 17:47:58 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 9 Oct 2015 09:41:05 +0200
x86/vdso: Define BUILD_VDSO while building and emit .eh_frame in asm
For the vDSO, user code wants runtime unwind info. Make sure
that, if we use .cfi directives, we generate it.
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/16e29ad8855e6508197000d8c41f56adb00d7580.1444091584.git.luto@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/entry/vdso/Makefile | 4 ++--
arch/x86/include/asm/dwarf2.h | 13 ++++++++++---
2 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 3bfb39e..265c0ed 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -67,7 +67,7 @@ $(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE
CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \
$(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \
-fno-omit-frame-pointer -foptimize-sibling-calls \
- -DDISABLE_BRANCH_PROFILING
+ -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
$(vobjs): KBUILD_CFLAGS += $(CFL)
@@ -131,7 +131,7 @@ targets += vdso32/vdso32.lds
targets += vdso32/note.o vdso32/vclock_gettime.o vdso32/system_call.o
targets += vdso32/vclock_gettime.o
-KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS))
+KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO
$(obj)/vdso32.so.dbg: KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
$(obj)/vdso32.so.dbg: asflags-$(CONFIG_X86_64) += -m32
diff --git a/arch/x86/include/asm/dwarf2.h b/arch/x86/include/asm/dwarf2.h
index de1cdaf..09133ba 100644
--- a/arch/x86/include/asm/dwarf2.h
+++ b/arch/x86/include/asm/dwarf2.h
@@ -36,15 +36,22 @@
#endif
#if defined(CONFIG_AS_CFI_SECTIONS) && defined(__ASSEMBLY__)
+#ifndef BUILD_VDSO
/*
* Emit CFI data in .debug_frame sections, not .eh_frame sections.
* The latter we currently just discard since we don't do DWARF
* unwinding at runtime. So only the offline DWARF information is
- * useful to anyone. Note we should not use this directive if this
- * file is used in the vDSO assembly, or if vmlinux.lds.S gets
- * changed so it doesn't discard .eh_frame.
+ * useful to anyone. Note we should not use this directive if
+ * vmlinux.lds.S gets changed so it doesn't discard .eh_frame.
*/
.cfi_sections .debug_frame
+#else
+ /*
+ * For the vDSO, emit both runtime unwind information and debug
+ * symbols for the .dbg file.
+ */
+ .cfi_sections .eh_frame, .debug_frame
+#endif
#endif
#else
--
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