linux-kernel - Re: static_branch/jump

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Message-ID: <877dlbzq09.fsf@oldenburg.str.redhat.com>
Date:   Fri, 09 Apr 2021 12:55:18 +0200
From:   Florian Weimer <fweimer@...hat.com>
To:     Ard Biesheuvel <ardb@...nel.org>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        linux-toolchains@...r.kernel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Jason Baron <jbaron@...mai.com>,
        "Steven Rostedt (VMware)" <rostedt@...dmis.org>
Subject: Re: static_branch/jump_label vs branch merging

* Ard Biesheuvel:

> Wouldn't that require the compiler to interpret the contents of the
> asm() block?

Yes and no.  It would require proper toolchain support, so in this case
a new ELF relocation type, with compiler, assembler, and linker support
to generate those relocations and process them.  As far as I understand
it, the kernel doesn't do things this way.

Thanks,
Florian