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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: Linux-Arch <linux-arch@vger.kernel.org>,
	linux-m32r@ml.linux-m32r.org,
	Luke Browning <LukeBrowning@us.ibm.com>,
	takata@linux-m32r.org, linux-kernel@vger.kernel.org,
	linuxppc-dev@ozlabs.org, Paul Mackerras <paulus@samba.org>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 1/2] Add thread_info_cache_init() to all archs
Date: Wed, 21 May 2008 16:38:20 -0400	[thread overview]
Message-ID: <1211402300.8297.240.camel@pasglop> (raw)
In-Reply-To: <20080521190659.GB12638@uranus.ravnborg.org>


On Wed, 2008-05-21 at 21:06 +0200, Sam Ravnborg wrote:
> It was discussed to add some run-time checks for this issue.
> But the examples given were a bit fluffy so I never integrated
> anything
> i kbuild to detect this.
> 
> As this is only a bug for const weak functions they could be made
> non-const
> if they are seldomly used?

With the asm("") trick ?

I suppose, but I'm also happy to just reject the bad gcc...

It shouldn't be too hard to do a test case made of 2 files.

test_foo.c

int foo(void)
{
	printf("good\n");
}

test_bar.c

int foo(void) __weak
{
}

int main(void)
{
	foo();
	return 0;
}

And check for "good" in the output of said program..

Can somebody test that ? Luke, you have a broken compiler, can you make
up some test that could be integrated in the kernel build system
easily ?

(I'm travelling right now, no time to play much with it myself).

Cheers,
Ben.

WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Linux-Arch <linux-arch@vger.kernel.org>,
	linux-m32r@ml.linux-m32r.org, takata@linux-m32r.org,
	linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org,
	Paul Mackerras <paulus@samba.org>,
	Luke Browning <LukeBrowning@us.ibm.com>
Subject: Re: [PATCH 1/2] Add thread_info_cache_init() to all archs
Date: Wed, 21 May 2008 16:38:20 -0400	[thread overview]
Message-ID: <1211402300.8297.240.camel@pasglop> (raw)
Message-ID: <20080521203820.rqNEGlBAhUhk20jHjL5paGCUPeYJFkw3sIUi3m2O_vw@z> (raw)
In-Reply-To: <20080521190659.GB12638@uranus.ravnborg.org>


On Wed, 2008-05-21 at 21:06 +0200, Sam Ravnborg wrote:
> It was discussed to add some run-time checks for this issue.
> But the examples given were a bit fluffy so I never integrated
> anything
> i kbuild to detect this.
> 
> As this is only a bug for const weak functions they could be made
> non-const
> if they are seldomly used?

With the asm("") trick ?

I suppose, but I'm also happy to just reject the bad gcc...

It shouldn't be too hard to do a test case made of 2 files.

test_foo.c

int foo(void)
{
	printf("good\n");
}

test_bar.c

int foo(void) __weak
{
}

int main(void)
{
	foo();
	return 0;
}

And check for "good" in the output of said program..

Can somebody test that ? Luke, you have a broken compiler, can you make
up some test that could be integrated in the kernel build system
easily ?

(I'm travelling right now, no time to play much with it myself).

Cheers,
Ben.



  reply	other threads:[~2008-05-21 20:38 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-04-10  3:22 [PATCH 1/2] Add thread_info_cache_init() to all archs Benjamin Herrenschmidt
2008-04-10  3:22 ` Benjamin Herrenschmidt
2008-04-10  3:22 ` Benjamin Herrenschmidt
2008-04-10  3:22 ` Benjamin Herrenschmidt
     [not found] ` <20080410032354.90CB1DDF0F-mnsaURCQ41sdnm+yROfE0A@public.gmane.org>
2008-04-10 21:46   ` Benjamin Herrenschmidt
2008-04-10 21:46     ` Benjamin Herrenschmidt
2008-04-14  0:19   ` Andrew Morton
2008-04-14  0:19     ` Andrew Morton
2008-04-14  0:19     ` Andrew Morton
2008-04-14  0:19     ` Andrew Morton
2008-04-14  0:38     ` Benjamin Herrenschmidt
2008-04-14  0:38       ` Benjamin Herrenschmidt
2008-04-14  2:13       ` Andrew Morton
2008-04-14  2:13         ` Andrew Morton
2008-04-14  2:13         ` Andrew Morton
     [not found]         ` <20080413191338.9776ebd0.akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
2008-04-18  3:58           ` Benjamin Herrenschmidt
2008-04-18  3:58             ` Benjamin Herrenschmidt
2008-04-18  3:58             ` Benjamin Herrenschmidt
2008-04-18  4:19             ` Andrew Morton
2008-04-18  4:19               ` Andrew Morton
2008-04-18  4:19               ` Andrew Morton
     [not found]               ` <20080417211905.8ff769fa.akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
2008-04-18  4:38                 ` Michael Ellerman
2008-04-18  4:38                   ` Michael Ellerman
2008-04-18  6:44                 ` Benjamin Herrenschmidt
2008-04-18  6:44                   ` Benjamin Herrenschmidt
2008-04-18  6:44                   ` Benjamin Herrenschmidt
2008-05-21 17:56                   ` Benjamin Herrenschmidt
2008-05-21 17:56                     ` Benjamin Herrenschmidt
2008-05-21 18:41                     ` Andrew Morton
2008-05-21 18:41                       ` Andrew Morton
2008-05-21 19:06                       ` Sam Ravnborg
2008-05-21 19:06                         ` Sam Ravnborg
2008-05-21 20:38                         ` Benjamin Herrenschmidt [this message]
2008-05-21 20:38                           ` Benjamin Herrenschmidt
2008-05-21 19:44                       ` Benjamin Herrenschmidt
2008-05-21 19:44                         ` Benjamin Herrenschmidt
2008-05-21 20:52                         ` Andrew Morton
2008-05-21 20:52                           ` Andrew Morton
2008-04-18  4:21             ` Kyle McMartin
2008-04-18  4:21               ` Kyle McMartin
  -- strict thread matches above, loose matches on Subject: below --
2008-04-10 23:36 Benjamin Herrenschmidt
2008-04-10 23:36 ` Benjamin Herrenschmidt
2008-04-10 23:36 ` Benjamin Herrenschmidt
2008-04-10 23:36 ` Benjamin Herrenschmidt

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