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Date:   Tue, 12 Jan 2021 12:54:21 +0100
From:   Borislav Petkov <>
To:     Josh Poimboeuf <>
Cc:     Nick Desaulniers <>,
        Fāng-ruì Sòng <>,
        Andy Lutomirski <>,
        Thomas Gleixner <>,
        Ingo Molnar <>, Arnd Bergmann <>,
        X86 ML <>, "H. Peter Anvin" <>,
        Nathan Chancellor <>,
        LKML <>,
        clang-built-linux <>
Subject: Re: [PATCH v3] x86/entry: emit a symbol for register restoring thunk

On Mon, Jan 11, 2021 at 07:59:52PM -0600, Josh Poimboeuf wrote:
> Right.  In the vast majority of cases, .L symbols are totally fine.
> The limitation now being imposed by objtool (due to these assembler
> changes) is that all code must be contained in an ELF symbol.  And .L
> symbols don't create such symbols.
> So basically, you can use an .L symbol *inside* a function or a code
> segment, you just can't use the .L symbol to contain the code using a
> SYM_*_START/END annotation pair.
> It only affects a tiny fraction of all .L usage.  Just a handful of code
> sites I think.

@Nick, this belongs into the commit message too pls.



would need some of that blurb added explaining to users *why* they
should not use .L local symbols as SYM_* macro arguments.



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