From f24f910884277aa6824bbc2dda4b5d0418d45c28 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Mon, 5 Oct 2015 17:47:58 -0700 Subject: [PATCH] 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 Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/16e29ad8855e6508197000d8c41f56adb00d7580.1444091584.git.luto@kernel.org Signed-off-by: Ingo Molnar --- 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 3bfb39e7b8b2..265c0ed68118 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 de1cdaf4d743..09133ba032b3 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 -- 2.34.1