From: Nick Desaulniers <ndesaulniers@google.com>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<x86@kernel.org>, Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>, "H . Peter Anvin" <hpa@zytor.com>,
LKML <linux-kernel@vger.kernel.org>,
"Jason A . Donenfeld" <Jason@zx2c4.com>,
Ingo Molnar <mingo@redhat.com>,
clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH 3/7] x86: remove always-defined CONFIG_AS_CFI_SIGNAL_FRAME
Date: Mon, 23 Mar 2020 13:45:17 -0700 [thread overview]
Message-ID: <CAKwvOd=V=HF3RBP5bMwgnAZsPg7nVewZiMQ7F3bh=D6_5ejBaQ@mail.gmail.com> (raw)
In-Reply-To: <20200323020844.17064-4-masahiroy@kernel.org>
On Sun, Mar 22, 2020 at 7:09 PM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> CONFIG_AS_CFI_SIGNAL_FRAME was introduced by commit adf1423698f0
> ("[PATCH] i386/x86-64: Work around gcc bug with noreturn functions
> in unwinder").
>
> We raise the minimal supported binutils version from time to time.
> The last bump was commit 1fb12b35e5ff ("kbuild: Raise the minimum
> required binutils version to 2.21").
>
> I confirmed the code in $(call as-instr,...) can be assembled by the
> binutils 2.21 assembler and also by LLVM integrated assembler.
>
> Remove CONFIG_AS_CFI_SIGNAL_FRAME, which is always defined.
grepping for CONFIG_AS_CFI_SIGNAL_FRAME, I see another use in
arch/arc/kernel/unwind.c. This change will cause inclusion of
additional code there, whereas for binutils produced within the past
ten years, there was not.
>
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> ---
>
> arch/x86/Makefile | 6 ++----
> arch/x86/include/asm/dwarf2.h | 5 -----
> 2 files changed, 2 insertions(+), 9 deletions(-)
>
> diff --git a/arch/x86/Makefile b/arch/x86/Makefile
> index 72f8f744ebd7..dd275008fc59 100644
> --- a/arch/x86/Makefile
> +++ b/arch/x86/Makefile
> @@ -177,8 +177,6 @@ ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
> KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
> endif
>
> -# 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 := $(call as-instr,.cfi_sections .debug_frame,-DCONFIG_AS_CFI_SECTIONS=1)
>
> # does binutils support specific instructions?
> @@ -190,8 +188,8 @@ sha1_ni_instr :=$(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-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_AFLAGS += $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr) $(adx_instr)
> +KBUILD_CFLAGS += $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr) $(adx_instr)
>
> KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
>
> diff --git a/arch/x86/include/asm/dwarf2.h b/arch/x86/include/asm/dwarf2.h
> index 90807583cad7..d6697aab5706 100644
> --- a/arch/x86/include/asm/dwarf2.h
> +++ b/arch/x86/include/asm/dwarf2.h
> @@ -20,12 +20,7 @@
> #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
Has no uses in the kernel.
> -#else
> -#define CFI_SIGNAL_FRAME
> -#endif
>
> #if defined(CONFIG_AS_CFI_SECTIONS)
> #ifndef BUILD_VDSO
> --
> 2.17.1
>
> --
--
Thanks,
~Nick Desaulniers
next prev parent reply other threads:[~2020-03-23 20:45 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-23 2:08 [PATCH 0/7] x86: remove always-defined CONFIG_AS_* options Masahiro Yamada
2020-03-23 2:08 ` [PATCH 1/7] x86: remove unneeded defined(__ASSEMBLY__) check from asm/dwarf2.h Masahiro Yamada
2020-03-23 2:08 ` [PATCH 2/7] x86: remove always-defined CONFIG_AS_CFI Masahiro Yamada
2020-03-23 20:37 ` Nick Desaulniers
2020-03-23 2:08 ` [PATCH 3/7] x86: remove always-defined CONFIG_AS_CFI_SIGNAL_FRAME Masahiro Yamada
2020-03-23 20:45 ` Nick Desaulniers [this message]
2020-03-23 2:08 ` [PATCH 4/7] x86: remove always-defined CONFIG_AS_CFI_SECTIONS Masahiro Yamada
2020-03-23 20:59 ` Nick Desaulniers
2020-03-23 2:08 ` [PATCH 5/7] x86: remove always-defined CONFIG_AS_SSSE3 Masahiro Yamada
2020-03-23 18:06 ` Jason A. Donenfeld
2020-03-23 20:44 ` Masahiro Yamada
2020-03-23 20:48 ` Jason A. Donenfeld
2020-03-23 21:01 ` Jason A. Donenfeld
2020-03-23 2:08 ` [PATCH 6/7] x86: remove always-defined CONFIG_AS_AVX Masahiro Yamada
2020-03-23 2:08 ` [PATCH 7/7] x86: add comments about the binutils version to support code in as-instr Masahiro Yamada
2020-03-23 4:07 ` [PATCH 0/7] x86: remove always-defined CONFIG_AS_* options Jason A. Donenfeld
2020-03-23 4:28 ` Jason A. Donenfeld
2020-03-23 6:35 ` Masahiro Yamada
2020-03-23 6:53 ` Jason A. Donenfeld
2020-03-23 9:52 ` Sedat Dilek
2020-03-23 19:50 ` Jason A. Donenfeld
2020-03-24 8:46 ` Sedat Dilek
2020-03-23 22:03 ` Masahiro Yamada
2020-03-23 22:10 ` Jason A. Donenfeld
2020-03-23 19:45 ` Nick Desaulniers
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