[RFC patch 2/7] x86/tsc: Set clocksource CLOCK_SOURCE_SUSPEND_ACCESS_OK

From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linuxfoundation.org>,
	Prarit Bhargava <prarit@redhat.com>,
	Mark Salyzyn <salyzyn@android.com>,
	Petr Mladek <pmladek@suse.com>, Ingo Molnar <mingo@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Joe Perches <joe@perches.com>
Subject: [RFC patch 2/7] x86/tsc: Set clocksource CLOCK_SOURCE_SUSPEND_ACCESS_OK
Date: Wed, 15 Nov 2017 19:15:33 +0100	[thread overview]
Message-ID: <20171115182657.303739978@linutronix.de> (raw)
In-Reply-To: 20171115181531.322572387@linutronix.de

[-- Attachment #1: x86-tsc--Set-clocksource-CLOCK_SOURCE_SUSPEND_ACCESS_OK.patch --]
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When TSC is non stop accross suspend then it can be accessed after
timekeeping_suspend(). Set the proper flag to indicate that.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 arch/x86/kernel/tsc.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Index: b/arch/x86/kernel/tsc.c
===================================================================

--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1240,8 +1240,10 @@ static int __init init_tsc_clocksource(v
 		clocksource_tsc.flags &= ~CLOCK_SOURCE_IS_CONTINUOUS;
 	}
 
-	if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC_S3))
-		clocksource_tsc.flags |= CLOCK_SOURCE_SUSPEND_NONSTOP;
+	if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC_S3)) {
+		clocksource_tsc.flags |= CLOCK_SOURCE_SUSPEND_NONSTOP |
+					 CLOCK_SOURCE_SUSPEND_ACCESS_OK;
+	}
 
 	/*
 	 * When TSC frequency is known (retrieved via MSR or CPUID), we skip
