From: Josh Poimboeuf <[email protected]> Enable sframe generation in the VDSO library so kernel and user space can unwind through it.
[ Jens Remus: Add support for SFrame V3. Prevent GNU_SFRAME program table entry to empty .sframe section. ] Signed-off-by: Josh Poimboeuf <[email protected]> Signed-off-by: Steven Rostedt (Google) <[email protected]> Signed-off-by: Jens Remus <[email protected]> --- arch/Kconfig | 7 +++++++ arch/x86/entry/vdso/Makefile | 10 +++++++--- arch/x86/entry/vdso/vdso-layout.lds.S | 7 +++++++ arch/x86/include/asm/dwarf2.h | 5 ++++- 4 files changed, 25 insertions(+), 4 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index dcb553136e0c..b5b3a83072f7 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -479,6 +479,13 @@ config HAVE_HARDLOCKUP_DETECTOR_ARCH It uses the same command line parameters, and sysctl interface, as the generic hardlockup detectors. +config AS_SFRAME + bool + +config AS_SFRAME3 + def_bool $(as-instr,.cfi_startproc\n.cfi_endproc,-Wa$(comma)--gsframe-3) + select AS_SFRAME + config UNWIND_USER bool diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index f247f5f5cb44..748e0a630e81 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 $(call if_changed,vdso2c) +ifeq ($(CONFIG_AS_SFRAME3),y) + SFRAME_CFLAGS := -Wa,--gsframe-3 +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) $(KSTACK_ERASE_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 60747905de2b..acdc55435d99 100644 --- a/arch/x86/entry/vdso/vdso-layout.lds.S +++ b/arch/x86/entry/vdso/vdso-layout.lds.S @@ -59,6 +59,9 @@ SECTIONS .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr .eh_frame : { KEEP (*(.eh_frame)) } :text +#ifdef CONFIG_AS_SFRAME + .sframe : { *(.sframe) } :text :sframe +#endif /* * Text is well-separated from actual data: there's plenty of @@ -87,6 +90,7 @@ 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 @@ -98,4 +102,7 @@ PHDRS dynamic PT_DYNAMIC FLAGS(4); /* PF_R */ note PT_NOTE FLAGS(4); /* PF_R */ eh_frame_hdr PT_GNU_EH_FRAME; +#ifdef CONFIG_AS_SFRAME + sframe PT_GNU_SFRAME; +#endif } diff --git a/arch/x86/include/asm/dwarf2.h b/arch/x86/include/asm/dwarf2.h index 65d958ef1178..ce294e6c9017 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. */ - +#if defined(__x86_64__) && defined(CONFIG_AS_SFRAME) + .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 -- 2.51.0
