From: Harvey Harrison <harvey.harrison@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: bunk@kernel.org, wli@holomorphy.com, sparclinux@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: sparc vs. gcc 4.3
Date: Mon, 03 Mar 2008 21:41:11 +0000 [thread overview]
Message-ID: <1204580471.22933.17.camel@brick> (raw)
In-Reply-To: <20080303.130348.25289482.davem@davemloft.net>
On Mon, 2008-03-03 at 13:03 -0800, David Miller wrote:
> From: Adrian Bunk <bunk@kernel.org>
> Date: Mon, 3 Mar 2008 21:26:51 +0200
>
> > LD arch/sparc/boot/image
> > arch/sparc/kernel/built-in.o:(__ex_table+0x394): undefined reference to `kernel_unaligned_trap_fault'
> ...
> > arch/sparc/kernel/built-in.o:(__ex_table+0x46c): undefined reference to `user_unaligned_trap_fault'
>
> > Does anyone have a clue what's going wrong here?
>
> We hit the same problem a while back on sparc64 too.
>
> GCC can't see how the inline asm is reachable so eliminates it
> entirely. We hide the label inside the inline asm string and call it
> from exception handlers.
>
> The way we fixed this on sparc64 was quite invasive (patch below for
> reference), so I'll try to come up with something simpler.
Could you hide the asm inside an actual function and annotate the
function with __used?
Similar to how the kprobes has a function called kretprobe_trampoline_holder
for their trampoline asm?
arch/x86/kernel/kprobes.c line 584
Cheers,
Harvey
WARNING: multiple messages have this Message-ID (diff)
From: Harvey Harrison <harvey.harrison@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: bunk@kernel.org, wli@holomorphy.com, sparclinux@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: sparc vs. gcc 4.3
Date: Mon, 03 Mar 2008 13:41:11 -0800 [thread overview]
Message-ID: <1204580471.22933.17.camel@brick> (raw)
In-Reply-To: <20080303.130348.25289482.davem@davemloft.net>
On Mon, 2008-03-03 at 13:03 -0800, David Miller wrote:
> From: Adrian Bunk <bunk@kernel.org>
> Date: Mon, 3 Mar 2008 21:26:51 +0200
>
> > LD arch/sparc/boot/image
> > arch/sparc/kernel/built-in.o:(__ex_table+0x394): undefined reference to `kernel_unaligned_trap_fault'
> ...
> > arch/sparc/kernel/built-in.o:(__ex_table+0x46c): undefined reference to `user_unaligned_trap_fault'
>
> > Does anyone have a clue what's going wrong here?
>
> We hit the same problem a while back on sparc64 too.
>
> GCC can't see how the inline asm is reachable so eliminates it
> entirely. We hide the label inside the inline asm string and call it
> from exception handlers.
>
> The way we fixed this on sparc64 was quite invasive (patch below for
> reference), so I'll try to come up with something simpler.
Could you hide the asm inside an actual function and annotate the
function with __used?
Similar to how the kprobes has a function called kretprobe_trampoline_holder
for their trampoline asm?
arch/x86/kernel/kprobes.c line 584
Cheers,
Harvey
next prev parent reply other threads:[~2008-03-03 21:41 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-03 19:26 sparc vs. gcc 4.3 Adrian Bunk
2008-03-03 19:26 ` Adrian Bunk
2008-03-03 21:03 ` David Miller
2008-03-03 21:03 ` David Miller
2008-03-03 21:41 ` Harvey Harrison [this message]
2008-03-03 21:41 ` Harvey Harrison
2008-03-03 22:02 ` David Miller
2008-03-03 22:02 ` David Miller
2008-03-03 23:02 ` David Miller
2008-03-03 23:02 ` David Miller
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