From: dave.korn.cygwin@googlemail.com (Dave Korn)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: Convert BUG() to use unreachable()
Date: Tue, 22 Dec 2009 14:09:02 +0000 [thread overview]
Message-ID: <4B30D2FE.9020209@gmail.com> (raw)
In-Reply-To: <20091221201059.GD11669@n2100.arm.linux.org.uk>
Russell King - ARM Linux wrote:
> On Mon, Dec 21, 2009 at 11:30:43AM -0800, Richard Henderson wrote:
>> On 12/17/2009 10:17 AM, Russell King - ARM Linux wrote:
>>> How is "size-optimal trap" defined?
>> E.g. Sparc and MIPS have "tcc" instructions that trap based on the
>> condition codes, and so we eliminate the branch. That's the only
>> optimization we apply with __builtin_trap.
>>
>>> Let me put it another way: I want this function to terminate with an
>>> explicit NULL pointer dereference in every case.
>> Then just use that.
>
> That's precisely what we have been using for many years.
I don't understand. It should still work just fine; the original version
posted appears to simply lack 'volatile' on the (int *) cast.
cheers,
DaveK
WARNING: multiple messages have this Message-ID (diff)
From: Dave Korn <dave.korn.cygwin@googlemail.com>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: "Richard Henderson" <rth@redhat.com>,
"Richard Guenther" <richard.guenther@gmail.com>,
"David Daney" <ddaney@caviumnetworks.com>,
"gcc@gcc.gnu.org" <gcc@gcc.gnu.org>,
"Jamie Lokier" <jamie@shareable.org>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Subject: Re: [PATCH] ARM: Convert BUG() to use unreachable()
Date: Tue, 22 Dec 2009 14:09:02 +0000 [thread overview]
Message-ID: <4B30D2FE.9020209@gmail.com> (raw)
In-Reply-To: <20091221201059.GD11669@n2100.arm.linux.org.uk>
Russell King - ARM Linux wrote:
> On Mon, Dec 21, 2009 at 11:30:43AM -0800, Richard Henderson wrote:
>> On 12/17/2009 10:17 AM, Russell King - ARM Linux wrote:
>>> How is "size-optimal trap" defined?
>> E.g. Sparc and MIPS have "tcc" instructions that trap based on the
>> condition codes, and so we eliminate the branch. That's the only
>> optimization we apply with __builtin_trap.
>>
>>> Let me put it another way: I want this function to terminate with an
>>> explicit NULL pointer dereference in every case.
>> Then just use that.
>
> That's precisely what we have been using for many years.
I don't understand. It should still work just fine; the original version
posted appears to simply lack 'volatile' on the (int *) cast.
cheers,
DaveK
next prev parent reply other threads:[~2009-12-22 14:09 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-08 9:55 [PATCH] ARM: Convert BUG() to use unreachable() Uwe Kleine-König
2009-12-08 9:55 ` Uwe Kleine-König
2009-12-08 17:07 ` David Daney
2009-12-10 17:50 ` Russell King - ARM Linux
2009-12-10 17:50 ` Russell King - ARM Linux
2009-12-10 17:55 ` David Daney
2009-12-16 13:58 ` Uwe Kleine-König
2009-12-16 13:58 ` Uwe Kleine-König
2009-12-17 15:01 ` Jamie Lokier
2009-12-17 15:01 ` Jamie Lokier
2009-12-17 17:09 ` David Daney
2009-12-17 17:17 ` Richard Guenther
2009-12-17 17:17 ` Richard Guenther
2009-12-17 18:17 ` Russell King - ARM Linux
2009-12-17 18:17 ` Russell King - ARM Linux
2009-12-17 18:35 ` Joe Buck
2009-12-17 18:35 ` Joe Buck
2009-12-17 19:06 ` Russell King - ARM Linux
2009-12-17 19:06 ` Russell King - ARM Linux
2009-12-17 19:14 ` Joe Buck
2009-12-17 19:14 ` Joe Buck
2009-12-17 19:33 ` David Daney
2009-12-17 19:33 ` Russell King - ARM Linux
2009-12-17 19:33 ` Russell King - ARM Linux
2009-12-17 19:38 ` Jamie Lokier
2009-12-17 19:38 ` Jamie Lokier
2009-12-17 19:48 ` Russell King - ARM Linux
2009-12-17 19:48 ` Russell King - ARM Linux
2009-12-17 19:58 ` Russell King - ARM Linux
2009-12-17 19:58 ` Russell King - ARM Linux
2009-12-17 19:04 ` Jamie Lokier
2009-12-17 19:04 ` Jamie Lokier
2009-12-21 19:30 ` Richard Henderson
2009-12-21 19:30 ` Richard Henderson
2009-12-21 20:10 ` Russell King - ARM Linux
2009-12-21 20:10 ` Russell King - ARM Linux
2009-12-22 14:09 ` Dave Korn [this message]
2009-12-22 14:09 ` Dave Korn
2009-12-22 14:12 ` Russell King - ARM Linux
2009-12-22 14:12 ` Russell King - ARM Linux
2009-12-22 14:49 ` Dave Korn
2009-12-22 14:49 ` Dave Korn
2009-12-22 11:33 ` Paolo Bonzini
2009-12-22 11:33 ` Paolo Bonzini
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