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 the macros so that we can clean up the vDSO annotations.
Signed-off-by: Andy Lutomirski <l...@kernel.org>
---
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 054ff969fcdb..e4a537ed5350 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 */
--
2.4.3
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