Unverified Commit 425c0a7b authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
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!210 x86/tsc: use topology_max_packages() in tsc watchdog check 

Merge Pull Request from: @juntianlinux 
 
[Description]​
Temporary fix for #I5U037

Occasionally TSC clocksource is wrongly judged as unstable watchdog like 'jiffies', HPET on some platforms like Skylake 4S. 

For normal cases, we can use nr_online_nodes <= 4 as a quick workaround for this issue. However, there are many cases that 'nr_online_nodes' could have issue. Intel is still working on a formal fix, the patch in this PR is a more general fix but still have open under discussion.

Generally, there are some corner cases, but we can use this for a temporary fix to this issue. In next step, we need to update this fix after upstream merging the final solution.

 
 
Link:https://gitee.com/openeuler/kernel/pulls/210

 
Reviewed-by: default avatarJiao Fenfang <jiaofenfang@uniontech.com>
Reviewed-by: default avatarChen Wei <chenwei@xfusion.com>
Reviewed-by: default avatarXibo.Wang <wangxb12@chinatelecom.cn>
Signed-off-by: default avatarXie XiuQi <xiexiuqi@huawei.com>
parents eda593e5 2558e3b3

arch/x86/kernel/tsc.c

+16 −26
Original line number Diff line number Diff line
@@ -1129,8 +1129,7 @@ static struct clocksource clocksource_tsc_early = { 
	.rating			= 299,

	.read			= read_tsc,

	.mask			= CLOCKSOURCE_MASK(64),

	.flags			= CLOCK_SOURCE_IS_CONTINUOUS |

				  CLOCK_SOURCE_MUST_VERIFY,

	.flags			= CLOCK_SOURCE_IS_CONTINUOUS,

	.vdso_clock_mode	= VDSO_CLOCKMODE_TSC,

	.enable			= tsc_cs_enable,

	.resume			= tsc_resume,
@@ -1178,12 +1177,6 @@ void mark_tsc_unstable(char *reason) 


EXPORT_SYMBOL_GPL(mark_tsc_unstable);



static void __init tsc_disable_clocksource_watchdog(void)

{

	clocksource_tsc_early.flags &= ~CLOCK_SOURCE_MUST_VERIFY;

	clocksource_tsc.flags &= ~CLOCK_SOURCE_MUST_VERIFY;

}



static void __init check_system_tsc_reliable(void)

{

#if defined(CONFIG_MGEODEGX1) || defined(CONFIG_MGEODE_LX) || defined(CONFIG_X86_GENERIC)
@@ -1200,23 +1193,6 @@ static void __init check_system_tsc_reliable(void) 
#endif

	if (boot_cpu_has(X86_FEATURE_TSC_RELIABLE))

		tsc_clocksource_reliable = 1;



	/*

	 * Disable the clocksource watchdog when the system has:

	 *  - TSC running at constant frequency

	 *  - TSC which does not stop in C-States

	 *  - the TSC_ADJUST register which allows to detect even minimal

	 *    modifications

	 *  - not more than two sockets. As the number of sockets cannot be

	 *    evaluated at the early boot stage where this has to be

	 *    invoked, check the number of online memory nodes as a

	 *    fallback solution which is an reasonable estimate.

	 */

	if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) &&

	    boot_cpu_has(X86_FEATURE_NONSTOP_TSC) &&

	    boot_cpu_has(X86_FEATURE_TSC_ADJUST) &&

	    nr_online_nodes <= 2)

		tsc_disable_clocksource_watchdog();

}



/*
@@ -1411,6 +1387,20 @@ static int __init init_tsc_clocksource(void) 
	if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC_S3))

		clocksource_tsc.flags |= CLOCK_SOURCE_SUSPEND_NONSTOP;



	/*

	 * Disable the clocksource watchdog when the system has:

	 *  - TSC running at constant frequency

	 *  - TSC which does not stop in C-States

	 *  - the TSC_ADJUST register which allows to detect even minimal

	 *    modifications

	 *  - not more than four sockets.

	 */

	if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) &&

	    boot_cpu_has(X86_FEATURE_NONSTOP_TSC) &&

	    boot_cpu_has(X86_FEATURE_TSC_ADJUST) &&

	    topology_max_packages() <= 4)

		clocksource_tsc.flags &= ~CLOCK_SOURCE_MUST_VERIFY;



	/*

	 * When TSC frequency is known (retrieved via MSR or CPUID), we skip

	 * the refined calibration and directly register it as a clocksource.
@@ -1545,7 +1535,7 @@ void __init tsc_init(void) 
	}



	if (tsc_clocksource_reliable || no_tsc_watchdog)

		tsc_disable_clocksource_watchdog();

		clocksource_tsc.flags &= ~CLOCK_SOURCE_MUST_VERIFY;



	clocksource_register_khz(&clocksource_tsc_early, tsc_khz);

	detect_art();