linux-kernel - [PATCH] x86, tsc: Remove checking cpu_has_tsc when CONFIG_X86

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Date:	Fri, 30 Oct 2009 21:18:57 +0600
From:	Rakib Mullick <rakib.mullick@...il.com>
To:	Ingo Molnar <mingo@...e.hu>, LKML <linux-kernel@...r.kernel.org>
Cc:	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>, x86@...nel.org
Subject: [PATCH] x86, tsc: Remove checking cpu_has_tsc when CONFIG_X86_TSC=n.

 When CONFIG_X86_TSC=n, we do not need to check cpu_has_tsc, we can
simply return with 0. Moreover cpu_has_tsc indicates whether cpu
tsc feature on or not, so it doesn't matter when CONFIG_X86_TSC=n.
Am I right? Or I'm missing anything?

----
Signed-off-by: Rakib Mullick <rakib.mullick@...il.com>

--- linus/arch/x86/include/asm/tsc.h	2009-10-17 13:12:59.000000000 +0600
+++ rakib/arch/x86/include/asm/tsc.h	2009-10-30 21:55:29.000000000 +0600
@@ -24,8 +24,7 @@ static inline cycles_t get_cycles(void)
 	unsigned long long ret = 0;

 #ifndef CONFIG_X86_TSC
-	if (!cpu_has_tsc)
-		return 0;
+	return 0;
 #endif
 	rdtscll(ret);

@@ -39,8 +38,7 @@ static __always_inline cycles_t vget_cyc
 	 * access boot_cpu_data (which is not VDSO-safe):
 	 */
 #ifndef CONFIG_X86_TSC
-	if (!cpu_has_tsc)
-		return 0;
+	return 0;
 #endif
 	return (cycles_t)__native_read_tsc();
 }
--
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