linux-kernel - Re: [PATCH -next] arm32/boot/compressed: Force hidden visibility for all symbol references

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Message-ID: <Z5OxAfyKq-d7YPSp@shell.armlinux.org.uk>
Date: Fri, 24 Jan 2025 15:25:53 +0000
From: "Russell King (Oracle)" <linux@...linux.org.uk>
To: Yuntao Liu <liuyuntao12@...wei.com>
Cc: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	ruanjinjie@...wei.com, kees@...nel.org, masahiroy@...nel.org,
	ardb@...nel.org
Subject: Re: [PATCH -next] arm32/boot/compressed: Force hidden visibility for
 all symbol references

On Fri, Jan 24, 2025 at 08:20:30AM +0000, Yuntao Liu wrote:
> Eliminate all GOT entries in the decompressor binary, by forcing hidden
> visibility for all symbol references, which informs the compiler that
> such references will be resolved at link time without the need for
> allocating GOT entries.

One question. Why.

I don't think this is desirable. We don't want the linker to fully
resolve references at link time - we specifically want a GOT so that
at run time the decompressor can resolve the references irrespective
of where the decompressor is loaded - in other words, allowing the
decompressor to be loaded anywhere in memory.

We do not link the decompressor for any specific address, and thus
the only way the decompressor can work is by fixing up the GOT.

Unless you can demonstrate that the GOT is no longer required, then
based on your commit description... hard NAK.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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