Re: [PATCH v3] purgatory: fix disabling debug info

From: Nathan Chancellor <nathan@kernel.org>
To: Alyssa Ross <hi@alyssa.is>
Cc: Masahiro Yamada <masahiroy@kernel.org>,
	Nick Cao <nickcao@nichi.co>,
	linux-kbuild@vger.kernel.org,
	Nick Desaulniers <ndesaulniers@google.com>,
	linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
	linux-riscv@lists.infradead.org, Tom Rix <trix@redhat.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	stable@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH v3] purgatory: fix disabling debug info
Date: Thu, 30 Mar 2023 15:29:28 -0700	[thread overview]
Message-ID: <20230330222928.GA644044@dev-arch.thelio-3990X> (raw)
In-Reply-To: <20230330182223.181775-1-hi@alyssa.is>

On Thu, Mar 30, 2023 at 06:22:24PM +0000, Alyssa Ross wrote:
> Since 32ef9e5054ec, -Wa,-gdwarf-2 is no longer used in KBUILD_AFLAGS.
> Instead, it includes -g, the appropriate -gdwarf-* flag, and also the
> -Wa versions of both of those if building with Clang and GNU as.  As a
> result, debug info was being generated for the purgatory objects, even
> though the intention was that it not be.
> 
> Fixes: 32ef9e5054ec ("Makefile.debug: re-enable debug info for .S files")
> Signed-off-by: Alyssa Ross <hi@alyssa.is>
> Cc: stable@vger.kernel.org
> Acked-by: Nick Desaulniers <ndesaulniers@google.com>

This is definitely more future proof.

Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>

> ---
> v2: https://lore.kernel.org/r/20230326182120.194541-1-hi@alyssa.is
> 
> Difference from v2: replaced asflags-remove-y with every possible
> debug flag with asflags-y += -g0, as suggested by Nick Desaulniers.
> 
> Additionally, I've CCed the x86 maintainers this time, since Masahiro
> said he would like acks from subsystem maintainers, and
> get_maintainer.pl didn't pick them the first time around.
> 
>  arch/riscv/purgatory/Makefile | 7 +------
>  arch/x86/purgatory/Makefile   | 3 +--
>  2 files changed, 2 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile
> index d16bf715a586..9c1e71853ee7 100644
> --- a/arch/riscv/purgatory/Makefile
> +++ b/arch/riscv/purgatory/Makefile
> @@ -84,12 +84,7 @@ CFLAGS_string.o			+= $(PURGATORY_CFLAGS)
>  CFLAGS_REMOVE_ctype.o		+= $(PURGATORY_CFLAGS_REMOVE)
>  CFLAGS_ctype.o			+= $(PURGATORY_CFLAGS)
>  
> -AFLAGS_REMOVE_entry.o		+= -Wa,-gdwarf-2
> -AFLAGS_REMOVE_memcpy.o		+= -Wa,-gdwarf-2
> -AFLAGS_REMOVE_memset.o		+= -Wa,-gdwarf-2
> -AFLAGS_REMOVE_strcmp.o		+= -Wa,-gdwarf-2
> -AFLAGS_REMOVE_strlen.o		+= -Wa,-gdwarf-2
> -AFLAGS_REMOVE_strncmp.o		+= -Wa,-gdwarf-2
> +asflags-y			+= -g0
>  
>  $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
>  		$(call if_changed,ld)
> diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
> index 17f09dc26381..8e6c81b1c8f7 100644
> --- a/arch/x86/purgatory/Makefile
> +++ b/arch/x86/purgatory/Makefile
> @@ -69,8 +69,7 @@ CFLAGS_sha256.o			+= $(PURGATORY_CFLAGS)
>  CFLAGS_REMOVE_string.o		+= $(PURGATORY_CFLAGS_REMOVE)
>  CFLAGS_string.o			+= $(PURGATORY_CFLAGS)
>  
> -AFLAGS_REMOVE_setup-x86_$(BITS).o	+= -Wa,-gdwarf-2
> -AFLAGS_REMOVE_entry64.o			+= -Wa,-gdwarf-2
> +asflags-y			+= -g0
>  
>  $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
>  		$(call if_changed,ld)
> -- 
> 2.37.1
> 
> 