linuxppc-dev.lists.ozlabs.org archive mirror
 help / color / mirror / Atom feed
From: Alan Modra <amodra@gmail.com>
To: Anton Blanchard <anton@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org, paulus@samba.org, wschmidt@us.ibm.com
Subject: Re: BUG_ON and gcc don't mix
Date: Tue, 20 Aug 2013 14:02:11 +0930	[thread overview]
Message-ID: <20130820043211.GC3430@bubble.grove.modra.org> (raw)
In-Reply-To: <20130820123750.7353f2f1@kryten>

On Tue, Aug 20, 2013 at 12:37:50PM +1000, Anton Blanchard wrote:
> address of the trap instruction for our bug exception table. Maybe
> we need a gcc builtin in which we can get a label on the trap
> instruction. Would that be possible?

Not your actual _EMIT_BUG_ENTRY, but something like this ought to work.
The only trick here is not putting anything after __builtin_trap()..

#define BUG_ON(x) do { \
	if (x) {					\
		__asm__ __volatile__ ("\n1:"		\
			"\t.section __bug_table,\"a\""	\
			"\n\t.long 1b"			\
			"\n\t.previous");		\
                __builtin_trap();			\
	}						\
} while (0)

int foo(unsigned int *bar)
{
        unsigned int holder_cpu;

        holder_cpu = *bar & 0xffff;
        BUG_ON(holder_cpu >= 32);

        return 1;
}

-- 
Alan Modra
Australia Development Lab, IBM



-- 
Alan Modra
Australia Development Lab, IBM

  parent reply	other threads:[~2013-08-20  4:32 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-20  2:37 BUG_ON and gcc don't mix Anton Blanchard
2013-08-20  4:24 ` Benjamin Herrenschmidt
2013-08-20  4:32 ` Alan Modra [this message]
2013-08-20  4:45   ` Alan Modra
2013-08-20  8:36     ` David Laight
2013-08-20 10:55       ` Anton Blanchard

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20130820043211.GC3430@bubble.grove.modra.org \
    --to=amodra@gmail.com \
    --cc=anton@samba.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=paulus@samba.org \
    --cc=wschmidt@us.ibm.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).