From: Yeoreum Yun <yeoreum.yun@arm.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>,
will@kernel.org, nathan@kernel.org,
nick.desaulniers+lkml@gmail.com, morbo@google.com,
justinstitt@google.com, broonie@kernel.org, maz@kernel.org,
oliver.upton@linux.dev, frederic@kernel.org, joey.gouly@arm.com,
james.morse@arm.com, hardevsinh.palaniya@siliconsignals.io,
shameerali.kolothum.thodi@huawei.com, ryan.roberts@arm.com,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
stable@vger.kernel.org
Subject: Re: [PATCH] arm64/cpufeature: annotate arm64_use_ng_mappings with ro_after_init to prevent wrong idmap generation
Date: Fri, 2 May 2025 19:14:12 +0100 [thread overview]
Message-ID: <aBULdGn+klwp8CEu@e129823.arm.com> (raw)
In-Reply-To: <aBUHlGvZuI2O0bbs@arm.com>
> On Fri, May 02, 2025 at 06:41:33PM +0200, Ard Biesheuvel wrote:
> > Making arm64_use_ng_mappings __ro_after_init seems like a useful
> > change by itself, so I am not objecting to that. But we don't solve it
> > more fundamentally, please at least add a big fat comment why it is
> > important that the variable remains there.
>
> Maybe something like the section reference checker we use for __init -
> verify that the early C code does not refer anything in the BSS section.
Maybe but it would be better to be checked at compile time (I don't
know it's possible) otherwise, early C code writer should check
mandatroy by calling is_kernel_bss_data() (not exist) for data it refers.
> --
> Catalin
--
Sincerely,
Yeoreum Yun
next prev parent reply other threads:[~2025-05-02 18:14 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-02 14:57 [PATCH] arm64/cpufeature: annotate arm64_use_ng_mappings with ro_after_init to prevent wrong idmap generation Yeoreum Yun
2025-05-02 16:25 ` Nathan Chancellor
2025-05-02 17:17 ` Yeoreum Yun
2025-05-02 16:41 ` Ard Biesheuvel
2025-05-02 17:23 ` Yeoreum Yun
2025-05-02 17:57 ` Catalin Marinas
2025-05-02 18:14 ` Yeoreum Yun [this message]
2025-05-03 10:06 ` Catalin Marinas
2025-05-03 11:22 ` Ard Biesheuvel
2025-05-03 14:52 ` Yeoreum Yun
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