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x86: remove always-defined CONFIG_AS_CFI 

CONFIG_AS_CFI was introduced by commit e2414910f2 ("[PATCH] x86:
Detect CFI support in the assembler at runtime"), and extended by
commit f0f12d85af ("x86_64: Check for .cfi_rel_offset in CFI probe").

We raise the minimal supported binutils version from time to time.
The last bump was commit 1fb12b35e5 ("kbuild: Raise the minimum
required binutils version to 2.21").

I confirmed the code in $(call as-instr,...) can be assembled by the
binutils 2.21 assembler and also by LLVM integrated assembler.

Remove CONFIG_AS_CFI, which is always defined.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Masahiro Yamada 2020-03-26 17:00:51 +09:00
parent 418d6e295e
commit 0f2661c4b9
2 changed files with 2 additions and 44 deletions
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10
arch/x86/Makefile
View File

@ -177,12 +177,6 @@ ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
endif
# Stackpointer is addressed different for 32 bit and 64 bit x86
sp-$(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 := $(call as-instr,.cfi_sections .debug_frame,-DCONFIG_AS_CFI_SECTIONS=1)
@ -196,8 +190,8 @@ sha1_ni_instr :=$(call as-instr,sha1msg1 %xmm0$(comma)%xmm1,-DCONFIG_AS_SHA1_NI=
sha256_ni_instr :=$(call as-instr,sha256msg1 %xmm0$(comma)%xmm1,-DCONFIG_AS_SHA256_NI=1)
adx_instr := $(call as-instr,adox %r10$(comma)%r10,-DCONFIG_AS_ADX=1)
KBUILD_AFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr) $(adx_instr)
KBUILD_CFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr) $(adx_instr)
KBUILD_AFLAGS += $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr) $(adx_instr)
KBUILD_CFLAGS += $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr) $(adx_instr)
KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)

36
arch/x86/include/asm/dwarf2.h
View File

@ -6,15 +6,6 @@
#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
@ -55,31 +46,4 @@
#endif
#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
#endif /* _ASM_X86_DWARF2_H */