linux-kernel - Re: [PATCH v2 0/3] arm64/boot: Forbid the use of BSS symbols in startup code

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Message-ID: <aB428b2F9qzE0zCI@e129823.arm.com>
Date: Fri, 9 May 2025 18:10:09 +0100
From: Yeoreum Yun <yeoreum.yun@....com>
To: Ard Biesheuvel <ardb+git@...gle.com>
Cc: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	will@...nel.org, catalin.marinas@....com, mark.rutland@....com,
	Ard Biesheuvel <ardb@...nel.org>
Subject: Re: [PATCH v2 0/3] arm64/boot: Forbid the use of BSS symbols in
 startup code

Hi Ard,
> From: Ard Biesheuvel <ardb@...nel.org>
>
> Move any variables accessed or assigned by the startup code out of BSS,
> and into .data, so that we can forbid the use of BSS variables
> altogether, by ASSERT()'ing in the linker script that each symbol made
> available to the startup code lives before __bss_start in the linker
> map.
>
> Changes since v1:
> - fix build error due to missing declaration in #1
> - work around Clang complaining about the ASSERT() expression in the
>   linker script
>
> Cc: Yeoreum Yun <yeoreum.yun@....com>

Sorry for late.
with commit 117c3b21d3c7 ("arm64: Rework checks for broken Cavium HW in the PI code"):

Tested-by: Yeoreum Yun <yeoreum.yun@....com>
Reviewed-by: Yeoreum Yun <yeoreum.yun@....com>

Thanks!

>
> Ard Biesheuvel (3):
>   arm64/boot: Move init_pgdir[] and init_idmap_pgdir[] into __pi_
>     namespace
>   arm64/boot: Move global CPU override variables out of BSS
>   arm64/boot: Disallow BSS exports to startup code
>
>  arch/arm64/include/asm/pgtable.h |  2 -
>  arch/arm64/kernel/cpufeature.c   | 22 +++----
>  arch/arm64/kernel/head.S         |  6 +-
>  arch/arm64/kernel/image-vars.h   | 66 ++++++++++----------
>  arch/arm64/kernel/pi/pi.h        |  1 +
>  arch/arm64/kernel/vmlinux.lds.S  | 10 +--
>  6 files changed, 54 insertions(+), 53 deletions(-)
>
>
> base-commit: 363cd2b81cfdf706bbfc9ec78db000c9b1ecc552
> --
> 2.49.0.987.g0cc8ee98dc-goog
>

--
Sincerely,
Yeoreum Yun