From: Sergei Shtylylov <sshtylyov@ru.mvista.com>
To: Ralf Baechle <ralf@linux-mips.org>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>,
Atsushi Nemoto <anemo@mba.ocn.ne.jp>,
linux-mips@linux-mips.org
Subject: Re: [PATCH] TX49 MFC0 bug workaround
Date: Fri, 03 Feb 2006 05:26:48 +0300 [thread overview]
Message-ID: <43E2BF68.2000208@ru.mvista.com> (raw)
In-Reply-To: <20060202165656.GC17352@linux-mips.org>
Hello.
Ralf Baechle wrote:
>>>Workaround: mask EXL bit of the result or place a nop before mfc0.
>>
>>[...]
>>
>>>@@ -55,8 +56,13 @@ __asm__ (
>>> " di \n"
>>> #else
>>> " mfc0 $1,$12 \n"
>>>+#if TX49XX_MFC0_WAR && defined(MODULE)
>>>+ " ori $1,3 \n"
>>>+ " xori $1,3 \n"
>>>+#else
>>> " ori $1,1 \n"
>>> " xori $1,1 \n"
>>>+#endif
>>> " .set noreorder \n"
>>> " mtc0 $1,$12 \n"
>>> #endif
>> Hmm, wouldn't that "nop" alternative be simpler?
> Simpler maybe - but this variant has zero runtime overhead.
And.. how do you imagine placing a NOP (which surely just moves MFC0 down
so that it's a 1st insn. on the next page). What if it'll move it to the
errata prone address from a safe one instead?
WBR, Sergei
next prev parent reply other threads:[~2006-02-03 2:19 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-02 16:34 [PATCH] TX49 MFC0 bug workaround Atsushi Nemoto
2006-02-02 16:38 ` Maciej W. Rozycki
2006-02-02 16:56 ` Ralf Baechle
2006-02-02 17:04 ` Atsushi Nemoto
2006-02-02 17:21 ` Atsushi Nemoto
2006-02-02 17:24 ` Ralf Baechle
2006-02-03 2:10 ` Atsushi Nemoto
2006-02-03 10:17 ` Maciej W. Rozycki
2006-02-03 14:44 ` Ralf Baechle
2006-02-06 9:36 ` Atsushi Nemoto
2006-02-06 23:22 ` Ralf Baechle
2006-02-03 2:26 ` Sergei Shtylylov [this message]
2006-02-03 2:50 ` Atsushi Nemoto
2006-02-02 16:46 ` Ralf Baechle
2006-02-02 18:46 ` Sergei Shtylylov
2006-02-02 22:11 ` Ralf Baechle
2006-02-03 1:17 ` Atsushi Nemoto
2006-02-03 2:12 ` Sergei Shtylylov
2006-02-03 2:22 ` Atsushi Nemoto
2006-02-07 15:32 ` Sergei Shtylylov
2006-02-07 15:32 ` Sergei Shtylylov
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