Enable sframe generation in the VDSO library so kernel and user space can unwind through it.
Signed-off-by: Josh Poimboeuf <jpoim...@kernel.org> --- arch/Kconfig | 3 +++ arch/x86/entry/vdso/Makefile | 10 +++++++--- arch/x86/entry/vdso/vdso-layout.lds.S | 3 +++ arch/x86/include/asm/dwarf2.h | 5 ++++- 4 files changed, 17 insertions(+), 4 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index 6682b2a53e34..65228c78fef0 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -435,6 +435,9 @@ config HAVE_HARDLOCKUP_DETECTOR_ARCH It uses the same command line parameters, and sysctl interface, as the generic hardlockup detectors. +config AS_SFRAME + def_bool $(as-instr,.cfi_sections .sframe\n.cfi_startproc\n.cfi_endproc) + config HAVE_PERF_REGS bool help diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index c9216ac4fb1e..478de89029d1 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -47,13 +47,17 @@ quiet_cmd_vdso2c = VDSO2C $@ $(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE $(call if_changed,vdso2c) +#ifdef CONFIG_AS_SFRAME +SFRAME_CFLAGS := -Wa$(comma)-gsframe +#endif + # # Don't omit frame pointers for ease of userspace debugging, but do # optimize sibling calls. # CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \ $(filter -g%,$(KBUILD_CFLAGS)) -fno-stack-protector \ - -fno-omit-frame-pointer -foptimize-sibling-calls \ + -fno-omit-frame-pointer $(SFRAME_CFLAGS) -foptimize-sibling-calls \ -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO ifdef CONFIG_MITIGATION_RETPOLINE @@ -63,7 +67,7 @@ endif endif $(vobjs): KBUILD_CFLAGS := $(filter-out $(PADDING_CFLAGS) $(CC_FLAGS_LTO) $(CC_FLAGS_CFI) $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) -$(vobjs): KBUILD_AFLAGS += -DBUILD_VDSO +$(vobjs): KBUILD_AFLAGS += -DBUILD_VDSO $(SFRAME_CFLAGS) # # vDSO code runs in userspace and -pg doesn't help with profiling anyway. @@ -104,7 +108,7 @@ $(obj)/%-x32.o: $(obj)/%.o FORCE targets += vdsox32.lds $(vobjx32s-y) -$(obj)/%.so: OBJCOPYFLAGS := -S --remove-section __ex_table +$(obj)/%.so: OBJCOPYFLAGS := -g --remove-section __ex_table $(obj)/%.so: $(obj)/%.so.dbg FORCE $(call if_changed,objcopy) diff --git a/arch/x86/entry/vdso/vdso-layout.lds.S b/arch/x86/entry/vdso/vdso-layout.lds.S index 506c9800a5aa..4dcde4747b07 100644 --- a/arch/x86/entry/vdso/vdso-layout.lds.S +++ b/arch/x86/entry/vdso/vdso-layout.lds.S @@ -63,6 +63,7 @@ SECTIONS .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr .eh_frame : { KEEP (*(.eh_frame)) } :text + .sframe : { *(.sframe) } :text :sframe /* * Text is well-separated from actual data: there's plenty of @@ -91,6 +92,7 @@ SECTIONS * Very old versions of ld do not recognize this name token; use the constant. */ #define PT_GNU_EH_FRAME 0x6474e550 +#define PT_GNU_SFRAME 0x6474e554 /* * We must supply the ELF program headers explicitly to get just one @@ -102,4 +104,5 @@ PHDRS dynamic PT_DYNAMIC FLAGS(4); /* PF_R */ note PT_NOTE FLAGS(4); /* PF_R */ eh_frame_hdr PT_GNU_EH_FRAME; + sframe PT_GNU_SFRAME; } diff --git a/arch/x86/include/asm/dwarf2.h b/arch/x86/include/asm/dwarf2.h index b195b3c8677e..1c354f648505 100644 --- a/arch/x86/include/asm/dwarf2.h +++ b/arch/x86/include/asm/dwarf2.h @@ -12,8 +12,11 @@ * For the vDSO, emit both runtime unwind information and debug * symbols for the .dbg file. */ - +#ifdef __x86_64__ + .cfi_sections .eh_frame, .debug_frame, .sframe +#else .cfi_sections .eh_frame, .debug_frame +#endif #define CFI_STARTPROC .cfi_startproc #define CFI_ENDPROC .cfi_endproc -- 2.48.1