From: David Laight <david.laight.linux@gmail.com>
To: Andreas Schwab <schwab@linux-m68k.org>
Cc: Marco Elver <elver@google.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
linux-m68k@lists.linux-m68k.org, linux-kernel@vger.kernel.org,
kasan-dev@googlegroups.com
Subject: Re: [PATCH] m68k: Implement _THIS_IP_ using inline asm
Date: Thu, 21 May 2026 19:03:36 +0100 [thread overview]
Message-ID: <20260521190336.44dc3882@pumpkin> (raw)
In-Reply-To: <87h5o0zteu.fsf@igel.home>
On Thu, 21 May 2026 17:14:33 +0200
Andreas Schwab <schwab@linux-m68k.org> wrote:
> On Mai 21 2026, Marco Elver wrote:
>
> > version. Additionally, avoiding taking the address of a label prevents
> > compilers from emitting spurious indirect branch targets (e.g. ENDBR or
> > BTI) under control-flow integrity schemes.
>
> Ignoring the fact that m68k will never gain such a feature, dot is still
> a label.
But it wont be one the compiler sees.
I think it is an assembler variable that is automatically updated,
so not actually a label that ends up in the symbol table.
Even the '1b:' in some of the other examples are only second class
labels.
-- David
> If you want to avoid a label, you need to use %pc(0) (or
> %pc(-2) for an address at insn boundary).
>
prev parent reply other threads:[~2026-05-21 18:03 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-21 12:34 [PATCH] m68k: Implement _THIS_IP_ using inline asm Marco Elver
2026-05-21 15:14 ` Andreas Schwab
2026-05-21 15:26 ` Marco Elver
2026-05-21 18:03 ` David Laight [this message]
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