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: Roland McGrath <roland@redhat.com>
LKML-Reference: <20100514044303.A6FE7400BE@magilla.sf.frob.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
Roland McGrath 2010-05-13 21:43:03 -07:00 committed by H. Peter Anvin
parent 5967ed87ad
commit 9e56529227
2 changed files with 15 additions and 2 deletions

View File

@ -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)

View File

@ -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
/*