From: Will Deacon <will@kernel.org>
To: Mark Brown <broonie@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/3] arm64: asm: Add new-style position independent function annotations
Date: Tue, 7 Jan 2020 14:44:08 +0000 [thread overview]
Message-ID: <20200107144407.GB29001@willie-the-truck> (raw)
In-Reply-To: <20200106195818.56351-2-broonie@kernel.org>
On Mon, Jan 06, 2020 at 07:58:16PM +0000, Mark Brown wrote:
> As part of an effort to make the annotations in assembly code clearer and
> more consistent new macros have been introduced, including replacements
> for ENTRY() and ENDPROC().
>
> On arm64 we have ENDPIPROC(), a custom version of ENDPROC() which is
> used for code that will need to run in position independent environments
> like EFI, it creates an alias for the function with the prefix __pi_ and
> then emits the standard ENDPROC. Add new-style macros to replace this
> which expand to the standard SYM_FUNC_*() and SYM_FUNC_ALIAS_*(),
> resulting in the same object code. These are added in linkage.h for
> consistency with where the generic assembler code has its macros.
>
> Signed-off-by: Mark Brown <broonie@kernel.org>
> ---
> arch/arm64/include/asm/linkage.h | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/arch/arm64/include/asm/linkage.h b/arch/arm64/include/asm/linkage.h
> index 1b266292f0be..23944ce14969 100644
> --- a/arch/arm64/include/asm/linkage.h
> +++ b/arch/arm64/include/asm/linkage.h
> @@ -4,4 +4,20 @@
> #define __ALIGN .align 2
> #define __ALIGN_STR ".align 2"
>
> +/*
> + * Annotate a function as position independent, i.e., safe to be called before
> + * the kernel virtual mapping is activated.
> + */
> +#define SYM_FUNC_START_PI(x) \
> + SYM_FUNC_START_ALIAS(__pi_##x) ASM_NL \
> + SYM_FUNC_START(x)
> +
> +#define SYM_FUNC_START_PI_WEAK(x) \
> + SYM_FUNC_START_ALIAS(__pi_##x) ASM_NL \
> + SYM_FUNC_START_WEAK(x)
Naming's hard, but I think this is particularly bad because it reads to me
like it's declaring a weak, position-independent symbol, whereas the weak
symbol is actually the version without the "__pi_" prefix. Maybe
SYM_FUNC_START_WEAK_PI() is a tiny bit better? Hrm.
Will
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next prev parent reply other threads:[~2020-01-07 14:44 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-06 19:58 [PATCH 0/3] arm64: Conversions to modern assembly annotations Mark Brown
2020-01-06 19:58 ` [PATCH 1/3] arm64: asm: Add new-style position independent function annotations Mark Brown
2020-01-07 14:44 ` Will Deacon [this message]
2020-01-07 16:45 ` Mark Brown
2020-01-06 19:58 ` [PATCH 2/3] arm64: lib: Use modern annotations for assembly functions Mark Brown
2020-01-07 14:44 ` Will Deacon
2020-01-07 17:47 ` Mark Brown
2020-01-08 12:29 ` Will Deacon
2020-01-10 16:56 ` Jiri Slaby
2020-01-15 18:43 ` Will Deacon
2020-01-06 19:58 ` [PATCH 3/3] arm64: mm: " Mark Brown
2020-01-07 14:43 ` Will Deacon
2020-01-07 16:42 ` Mark Brown
2020-01-08 12:17 ` Will Deacon
2020-01-08 13:50 ` Mark Brown
2020-01-08 14:56 ` Will Deacon
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