linux-kernel - Re: [PATCH 10/46] static_call, lto: Mark func_a() as __visible_on

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Date:   Mon, 14 Nov 2022 12:29:30 -0800
From:   Andi Kleen <andi@...stfloor.org>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     "Jiri Slaby (SUSE)" <jirislaby@...nel.org>,
        linux-kernel@...r.kernel.org, Andi Kleen <andi@...stfloor.org>,
        Josh Poimboeuf <jpoimboe@...nel.org>,
        Jason Baron <jbaron@...mai.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ard Biesheuvel <ardb@...nel.org>,
        Martin Liska <mliska@...e.cz>, Jiri Slaby <jslaby@...e.cz>
Subject: Re: [PATCH 10/46] static_call, lto: Mark func_a() as __visible_on_lto

On Mon, Nov 14, 2022 at 04:54:16PM +0100, Peter Zijlstra wrote:
> On Mon, Nov 14, 2022 at 12:43:08PM +0100, Jiri Slaby (SUSE) wrote:
> 
> > -static int func_a(int x)
> > +__visible_on_lto int sc_func_a(int x)
> 
> >  } static_call_data [] __initdata = {
> >        { NULL,   2, 3 },
> >        { func_b, 2, 4 },
> > -      { func_a, 2, 3 }
> > +      { sc_func_a, 2, 3 }
> >  };
> 
> I must say I really hate this. Also, with address taken, it still
> eliminiates it?

It doesn't eliminate it, but makes it static, which causes the label to
change, so the assembler reference breaks.

-Andi