linux-kernel - [PATCH] Oddity in mxcsr_feature_mask

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Message-ID: <20070608102250.GE4943@implementation>
Date:	Fri, 8 Jun 2007 18:22:50 +0800
From:	Samuel Thibault <samuel.thibault@...-lyon.org>
To:	linux-kernel@...r.kernel.org, akpm@...gle.com
Subject: [PATCH] Oddity in mxcsr_feature_mask_init()

Hi,

In arch/i386/kernel/i387.c:mxcsr_feature_mask_init(), one can read:

	asm volatile("fxsave %0" : : "m" (current->thread.i387.fxsave)); 

But I would rather have written:

	asm("fxsave %0" : "=m" (current->thread.i387.fxsave)); 

Considering the code around, it doesn't do much difference, but it makes
more sense (i.e. we just fill fxsave).

Samuel

Signed-off-by: Samuel Thibault <samuel.thibault@...-lyon.org>

--- linux-2.6.21-orig/arch/i386/kernel/i387.c.orig	2007-06-08 18:18:10.000000000 +0800
+++ linux-2.6.21-orig/arch/i386/kernel/i387.c	2007-06-08 18:18:22.000000000 +0800
@@ -32,7 +32,7 @@
 	clts();
 	if (cpu_has_fxsr) {
 		memset(&current->thread.i387.fxsave, 0, sizeof(struct i387_fxsave_struct));
-		asm volatile("fxsave %0" : : "m" (current->thread.i387.fxsave)); 
+		asm("fxsave %0" : "=m" (current->thread.i387.fxsave)); 
 		mask = current->thread.i387.fxsave.mxcsr_mask;
 		if (mask == 0) mask = 0x0000ffbf;
 	} 
-
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