From: Segher Boessenkool <segher@kernel.crashing.org>
To: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: linuxppc-dev@lists.ozlabs.org, Paul Mackerras <paulus@samba.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] powerpc: use __builtin_trap() in BUG/WARN macros.
Date: Mon, 19 Aug 2019 08:23:13 -0500 [thread overview]
Message-ID: <20190819132313.GH31406@gate.crashing.org> (raw)
In-Reply-To: <20510ce03cc9463f1c9e743c1d93b939de501b53.1566219503.git.christophe.leroy@c-s.fr>
On Mon, Aug 19, 2019 at 01:06:31PM +0000, Christophe Leroy wrote:
> Note that we keep using an assembly text using "twi 31, 0, 0" for
> inconditional traps because GCC drops all code after
> __builtin_trap() when the condition is always true at build time.
As I said, it can also do this for conditional traps, if it can prove
the condition is always true.
Can you put the bug table asm *before* the __builtin_trap maybe? That
should make it all work fine... If you somehow can tell what machine
instruction is that trap, anyway.
Segher
WARNING: multiple messages have this Message-ID (diff)
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 3/3] powerpc: use __builtin_trap() in BUG/WARN macros.
Date: Mon, 19 Aug 2019 08:23:13 -0500 [thread overview]
Message-ID: <20190819132313.GH31406@gate.crashing.org> (raw)
In-Reply-To: <20510ce03cc9463f1c9e743c1d93b939de501b53.1566219503.git.christophe.leroy@c-s.fr>
On Mon, Aug 19, 2019 at 01:06:31PM +0000, Christophe Leroy wrote:
> Note that we keep using an assembly text using "twi 31, 0, 0" for
> inconditional traps because GCC drops all code after
> __builtin_trap() when the condition is always true at build time.
As I said, it can also do this for conditional traps, if it can prove
the condition is always true.
Can you put the bug table asm *before* the __builtin_trap maybe? That
should make it all work fine... If you somehow can tell what machine
instruction is that trap, anyway.
Segher
next prev parent reply other threads:[~2019-08-19 13:27 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-19 13:06 [PATCH 1/3] powerpc: don't use __WARN() for WARN_ON() Christophe Leroy
2019-08-19 13:06 ` Christophe Leroy
2019-08-19 13:06 ` [PATCH 2/3] powerpc: refactoring BUG/WARN macros Christophe Leroy
2019-08-19 13:06 ` Christophe Leroy
2019-11-25 10:46 ` Michael Ellerman
2019-08-19 13:06 ` [PATCH 3/3] powerpc: use __builtin_trap() in " Christophe Leroy
2019-08-19 13:06 ` Christophe Leroy
2019-08-19 13:23 ` Segher Boessenkool [this message]
2019-08-19 13:23 ` Segher Boessenkool
2019-08-19 14:08 ` Christophe Leroy
2019-08-19 14:08 ` Christophe Leroy
2019-08-19 14:37 ` Segher Boessenkool
2019-08-19 14:37 ` Segher Boessenkool
2019-08-19 15:05 ` Christophe Leroy
2019-08-19 15:05 ` Christophe Leroy
2019-08-19 15:45 ` Segher Boessenkool
2019-08-19 15:45 ` Segher Boessenkool
2019-08-23 15:35 ` Christophe Leroy
2019-08-23 15:35 ` Christophe Leroy
2019-08-19 16:28 ` [PATCH 1/3] powerpc: don't use __WARN() for WARN_ON() Kees Cook
2019-08-19 16:28 ` Kees Cook
2019-08-19 17:29 ` Clean up cut-here even harder (was Re: [PATCH 1/3] powerpc: don't use __WARN() for WARN_ON()) Kees Cook
2019-08-19 17:29 ` Kees Cook
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