From: Ralf Baechle <ralf@linux-mips.org>
To: mansoor <mansoor@isofttech.com>
Cc: linux-mips@linux-mips.org
Subject: Re: Disabling lwc0 instruction
Date: Tue, 9 Nov 2004 14:24:18 +0100 [thread overview]
Message-ID: <20041109132418.GE5652@linux-mips.org> (raw)
In-Reply-To: <04e601c4c65c$2fdc15a0$8c00a8c0@mansoor>
On Tue, Nov 09, 2004 at 06:31:11PM +0530, mansoor wrote:
> Iam working on lx4189. This core doesnt support
> "lwc0" instruction but my tool chain generates
> this instruction.
>
> So when I run some applications it throws
> "unknown instruction" exception.
>
> How can solve this issue ?
>
> I have few solutions but I dont know
> whether its correct.
>
>
> 1) Re-build the toolchain with this instruction
> disbaled. But how to do this ?.
> 2) Write an exception handler to handle this
> instruction. The exact replacement would be
> "mfc0". how to do this ?
No. lwc0 is ll, load linked. In 2.6 define cpu_has_llsc to return 0 in
your system's cpu-feature-override.h. In 2.4 disable CONFIG_CPU_HAS_LLSC.
The kernel actually has an emulation for ll/sc in applications which
enables running of application code using ll/sc on ll/sc-less processors.
You should try to find why this seems to fail for you. Maybe this Lexra
kernel is simply super-ancient? If it's as old as it seems you should
replace it as it has various exploitable security holes.
Ralf
prev parent reply other threads:[~2004-11-09 13:24 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-11-09 13:01 Disabling lwc0 instruction mansoor
2004-11-09 13:01 ` mansoor
2004-11-09 13:24 ` Ralf Baechle [this message]
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