From: Mark Rutland <mark.rutland@arm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: x86@kernel.org, jpoimboe@redhat.com,
linux-kernel@vger.kernel.org, linux-toolchains@vger.kernel.org
Subject: Re: [PATCH] linkage: Fix issue with missing symbol size
Date: Tue, 3 May 2022 15:30:28 +0100 [thread overview]
Message-ID: <YnE8hLAYY93xkgdv@lakrids> (raw)
In-Reply-To: <20220429091859.GS2731@worktop.programming.kicks-ass.net>
On Fri, Apr 29, 2022 at 11:18:59AM +0200, Peter Zijlstra wrote:
>
> Occasionally, typically when a function doesn't end with 'ret', an
> alias on that function will have 0 size.
>
> The difference between what GCC generates and our linkage magic, is
> that GCC doesn't appear to provide .size for the alias'ed symbol at
> all. And indeed, removing this directive cures the issue.
>
> Additionally, GCC also doesn't emit .type for alias symbols either, so
> also omit that.
>
> Fixes: e0891269a8c2 ("linkage: add SYM_FUNC_ALIAS{,_LOCAL,_WEAK}()")
> Suggested-by: Mark Rutland <mark.rutland@arm.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Sorry about this!
FWIW:
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Thanks,
Mark.
> ---
> include/linux/linkage.h | 15 ++++++---------
> 1 file changed, 6 insertions(+), 9 deletions(-)
>
> --- a/include/linux/linkage.h
> +++ b/include/linux/linkage.h
> @@ -171,12 +171,9 @@
>
> /* SYM_ALIAS -- use only if you have to */
> #ifndef SYM_ALIAS
> -#define SYM_ALIAS(alias, name, sym_type, linkage) \
> - linkage(alias) ASM_NL \
> - .set alias, name ASM_NL \
> - .type alias sym_type ASM_NL \
> - .set .L__sym_size_##alias, .L__sym_size_##name ASM_NL \
> - .size alias, .L__sym_size_##alias
> +#define SYM_ALIAS(alias, name, linkage) \
> + linkage(alias) ASM_NL \
> + .set alias, name ASM_NL
> #endif
>
> /* === code annotations === */
> @@ -261,7 +258,7 @@
> */
> #ifndef SYM_FUNC_ALIAS
> #define SYM_FUNC_ALIAS(alias, name) \
> - SYM_ALIAS(alias, name, SYM_T_FUNC, SYM_L_GLOBAL)
> + SYM_ALIAS(alias, name, SYM_L_GLOBAL)
> #endif
>
> /*
> @@ -269,7 +266,7 @@
> */
> #ifndef SYM_FUNC_ALIAS_LOCAL
> #define SYM_FUNC_ALIAS_LOCAL(alias, name) \
> - SYM_ALIAS(alias, name, SYM_T_FUNC, SYM_L_LOCAL)
> + SYM_ALIAS(alias, name, SYM_L_LOCAL)
> #endif
>
> /*
> @@ -277,7 +274,7 @@
> */
> #ifndef SYM_FUNC_ALIAS_WEAK
> #define SYM_FUNC_ALIAS_WEAK(alias, name) \
> - SYM_ALIAS(alias, name, SYM_T_FUNC, SYM_L_WEAK)
> + SYM_ALIAS(alias, name, SYM_L_WEAK)
> #endif
>
> /* SYM_CODE_START -- use for non-C (special) functions */
>
prev parent reply other threads:[~2022-05-03 14:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-29 9:18 [PATCH] linkage: Fix issue with missing symbol size Peter Zijlstra
2022-04-29 20:12 ` Josh Poimboeuf
2022-04-29 21:06 ` Fāng-ruì Sòng
2022-05-03 14:30 ` Mark Rutland [this message]
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