From 7b956f035a9ef8bd3ef5490f49fc1bd834d8a70a Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Mon, 5 Oct 2015 17:47:57 -0700 Subject: [PATCH] x86/asm: Re-add parts of the manual CFI infrastructure Commit: 131484c8da97 ("x86/debug: Remove perpetually broken, unmaintainable dwarf annotations") removed all the manual DWARF annotations outside the vDSO. It also removed the macros we used for the manual annotations. Re-add these macros so that we can clean up the vDSO annotations. 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/4c70bb98a8b773c8ccfaabf6745e569ff43e7f65.1444091584.git.luto@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/Makefile | 10 +- arch/x86/include/asm/dwarf2.h | 170 ++++++++++++++++++++++++++++++++++ 2 files changed, 178 insertions(+), 2 deletions(-) create mode 100644 arch/x86/include/asm/dwarf2.h diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 747860c696e1..2dfaa72260b4 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -159,6 +159,12 @@ endif sp-$(CONFIG_X86_32) := esp sp-$(CONFIG_X86_64) := rsp +# do binutils support CFI? +cfi := $(call as-instr,.cfi_startproc\n.cfi_rel_offset $(sp-y)$(comma)0\n.cfi_endproc,-DCONFIG_AS_CFI=1) +# is .cfi_signal_frame supported too? +cfi-sigframe := $(call as-instr,.cfi_startproc\n.cfi_signal_frame\n.cfi_endproc,-DCONFIG_AS_CFI_SIGNAL_FRAME=1) +cfi-sections := $(call as-instr,.cfi_sections .debug_frame,-DCONFIG_AS_CFI_SECTIONS=1) + # does binutils support specific instructions? asinstr := $(call as-instr,fxsaveq (%rax),-DCONFIG_AS_FXSAVEQ=1) asinstr += $(call as-instr,pshufb %xmm0$(comma)%xmm0,-DCONFIG_AS_SSSE3=1) @@ -166,8 +172,8 @@ asinstr += $(call as-instr,crc32l %eax$(comma)%eax,-DCONFIG_AS_CRC32=1) avx_instr := $(call as-instr,vxorps %ymm0$(comma)%ymm1$(comma)%ymm2,-DCONFIG_AS_AVX=1) avx2_instr :=$(call as-instr,vpbroadcastb %xmm0$(comma)%ymm1,-DCONFIG_AS_AVX2=1) -KBUILD_AFLAGS += $(asinstr) $(avx_instr) $(avx2_instr) -KBUILD_CFLAGS += $(asinstr) $(avx_instr) $(avx2_instr) +KBUILD_AFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) +KBUILD_CFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) LDFLAGS := -m elf_$(UTS_MACHINE) diff --git a/arch/x86/include/asm/dwarf2.h b/arch/x86/include/asm/dwarf2.h new file mode 100644 index 000000000000..de1cdaf4d743 --- /dev/null +++ b/arch/x86/include/asm/dwarf2.h @@ -0,0 +1,170 @@ +#ifndef _ASM_X86_DWARF2_H +#define _ASM_X86_DWARF2_H + +#ifndef __ASSEMBLY__ +#warning "asm/dwarf2.h should be only included in pure assembly files" +#endif + +/* + * Macros for dwarf2 CFI unwind table entries. + * See "as.info" for details on these pseudo ops. Unfortunately + * they are only supported in very new binutils, so define them + * away for older version. + */ + +#ifdef CONFIG_AS_CFI + +#define CFI_STARTPROC .cfi_startproc +#define CFI_ENDPROC .cfi_endproc +#define CFI_DEF_CFA .cfi_def_cfa +#define CFI_DEF_CFA_REGISTER .cfi_def_cfa_register +#define CFI_DEF_CFA_OFFSET .cfi_def_cfa_offset +#define CFI_ADJUST_CFA_OFFSET .cfi_adjust_cfa_offset +#define CFI_OFFSET .cfi_offset +#define CFI_REL_OFFSET .cfi_rel_offset +#define CFI_REGISTER .cfi_register +#define CFI_RESTORE .cfi_restore +#define CFI_REMEMBER_STATE .cfi_remember_state +#define CFI_RESTORE_STATE .cfi_restore_state +#define CFI_UNDEFINED .cfi_undefined +#define CFI_ESCAPE .cfi_escape + +#ifdef CONFIG_AS_CFI_SIGNAL_FRAME +#define CFI_SIGNAL_FRAME .cfi_signal_frame +#else +#define CFI_SIGNAL_FRAME +#endif + +#if defined(CONFIG_AS_CFI_SECTIONS) && defined(__ASSEMBLY__) + /* + * 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. + */ + .cfi_sections .debug_frame +#endif + +#else + +/* + * Due to the structure of pre-exisiting code, don't use assembler line + * comment character # to ignore the arguments. Instead, use a dummy macro. + */ +.macro cfi_ignore a=0, b=0, c=0, d=0 +.endm + +#define CFI_STARTPROC cfi_ignore +#define CFI_ENDPROC cfi_ignore +#define CFI_DEF_CFA cfi_ignore +#define CFI_DEF_CFA_REGISTER cfi_ignore +#define CFI_DEF_CFA_OFFSET cfi_ignore +#define CFI_ADJUST_CFA_OFFSET cfi_ignore +#define CFI_OFFSET cfi_ignore +#define CFI_REL_OFFSET cfi_ignore +#define CFI_REGISTER cfi_ignore +#define CFI_RESTORE cfi_ignore +#define CFI_REMEMBER_STATE cfi_ignore +#define CFI_RESTORE_STATE cfi_ignore +#define CFI_UNDEFINED cfi_ignore +#define CFI_ESCAPE cfi_ignore +#define CFI_SIGNAL_FRAME cfi_ignore + +#endif + +/* + * An attempt to make CFI annotations more or less + * correct and shorter. It is implied that you know + * what you're doing if you use them. + */ +#ifdef __ASSEMBLY__ +#ifdef CONFIG_X86_64 + .macro pushq_cfi reg + pushq \reg + CFI_ADJUST_CFA_OFFSET 8 + .endm + + .macro pushq_cfi_reg reg + pushq %\reg + CFI_ADJUST_CFA_OFFSET 8 + CFI_REL_OFFSET \reg, 0 + .endm + + .macro popq_cfi reg + popq \reg + CFI_ADJUST_CFA_OFFSET -8 + .endm + + .macro popq_cfi_reg reg + popq %\reg + CFI_ADJUST_CFA_OFFSET -8 + CFI_RESTORE \reg + .endm + + .macro pushfq_cfi + pushfq + CFI_ADJUST_CFA_OFFSET 8 + .endm + + .macro popfq_cfi + popfq + CFI_ADJUST_CFA_OFFSET -8 + .endm + + .macro movq_cfi reg offset=0 + movq %\reg, \offset(%rsp) + CFI_REL_OFFSET \reg, \offset + .endm + + .macro movq_cfi_restore offset reg + movq \offset(%rsp), %\reg + CFI_RESTORE \reg + .endm +#else /*!CONFIG_X86_64*/ + .macro pushl_cfi reg + pushl \reg + CFI_ADJUST_CFA_OFFSET 4 + .endm + + .macro pushl_cfi_reg reg + pushl %\reg + CFI_ADJUST_CFA_OFFSET 4 + CFI_REL_OFFSET \reg, 0 + .endm + + .macro popl_cfi reg + popl \reg + CFI_ADJUST_CFA_OFFSET -4 + .endm + + .macro popl_cfi_reg reg + popl %\reg + CFI_ADJUST_CFA_OFFSET -4 + CFI_RESTORE \reg + .endm + + .macro pushfl_cfi + pushfl + CFI_ADJUST_CFA_OFFSET 4 + .endm + + .macro popfl_cfi + popfl + CFI_ADJUST_CFA_OFFSET -4 + .endm + + .macro movl_cfi reg offset=0 + movl %\reg, \offset(%esp) + CFI_REL_OFFSET \reg, \offset + .endm + + .macro movl_cfi_restore offset reg + movl \offset(%esp), %\reg + CFI_RESTORE \reg + .endm +#endif /*!CONFIG_X86_64*/ +#endif /*__ASSEMBLY__*/ + +#endif /* _ASM_X86_DWARF2_H */