linux-kernel - [PATCH] x86: fix sparse error in traps

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Message-Id: <1202178720.6452.12.camel@brick>
Date:	Mon, 04 Feb 2008 18:32:00 -0800
From:	Harvey Harrison <harvey.harrison@...il.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH] x86: fix sparse error in traps_32.c

arch/x86/kernel/traps_32.c:1193:31: error: dubious one-bit signed bitfield

This was being used to ensure the proper alignment of the FXSAVE/FXRSTOR data.
This would create a sparse error in the _correct_ cases, hiding further
warnings.  Use BUILD_BUG_ON instead.

Signed-off-by: Harvey Harrison <harvey.harrison@...il.com>
---
 arch/x86/kernel/traps_32.c |   15 +++++----------
 1 files changed, 5 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/traps_32.c b/arch/x86/kernel/traps_32.c
index 2f94f69..47ca425 100644
--- a/arch/x86/kernel/traps_32.c
+++ b/arch/x86/kernel/traps_32.c
@@ -1182,17 +1182,12 @@ void __init trap_init(void)
 #endif
 	set_trap_gate(19,&simd_coprocessor_error);
 
+	/*
+	 * Verify that the FXSAVE/FXRSTOR data will be 16-byte aligned.
+	 * Generate a build-time error if the alignment is wrong.
+	 */
+	BUILD_BUG_ON(offsetof(struct task_struct, thread.i387.fxsave) & 15);
 	if (cpu_has_fxsr) {
-		/*
-		 * Verify that the FXSAVE/FXRSTOR data will be 16-byte aligned.
-		 * Generates a compile-time "error: zero width for bit-field" if
-		 * the alignment is wrong.
-		 */
-		struct fxsrAlignAssert {
-			int _:!(offsetof(struct task_struct,
-					thread.i387.fxsave) & 15);
-		};
-
 		printk(KERN_INFO "Enabling fast FPU save and restore... ");
 		set_in_cr4(X86_CR4_OSFXSR);
 		printk("done.\n");
-- 
1.5.4.rc5.1138.g2602



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