Commit 9e565292 authored by Roland McGrath's avatar Roland McGrath Committed by H. Peter Anvin
Browse files

x86: Use .cfi_sections for assembly code 



The newer assemblers support the .cfi_sections directive so we can put
the CFI from .S files into the .debug_frame section that is preserved
in unstripped vmlinux and in separate debuginfo, rather than the
.eh_frame section that is now discarded by vmlinux.lds.S.

Signed-off-by: default avatarRoland McGrath <roland@redhat.com>
LKML-Reference: <20100514044303.A6FE7400BE@magilla.sf.frob.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent 5967ed87

arch/x86/Makefile

+3 −2
Original line number Diff line number Diff line
@@ -95,8 +95,9 @@ sp-$(CONFIG_X86_64) := rsp 
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)

KBUILD_AFLAGS += $(cfi) $(cfi-sigframe)

KBUILD_CFLAGS += $(cfi) $(cfi-sigframe)

cfi-sections := $(call as-instr,.cfi_sections .debug_frame,-DCONFIG_AS_CFI_SECTIONS=1)

KBUILD_AFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections)

KBUILD_CFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections)



LDFLAGS := -m elf_$(UTS_MACHINE)

arch/x86/include/asm/dwarf2.h

+12 −0
Original line number Diff line number Diff line
@@ -34,6 +34,18 @@ 
#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



/*

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