diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2017-05-31 17:52:04 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2017-06-04 21:55:53 +0200 |
| commit | 855615eee9b1989cac8ec5eaae4562db081a239b (patch) | |
| tree | 9aedea64e6cadd4846e811d272f4d737092f1208 /arch/x86/kernel/tsc_sync.c | |
| parent | bd9240a18edfbfa72e957fc2ba831cf1f13ea073 (diff) | |
x86/tsc: Remove the TSC_ADJUST clamp
Now that all affected platforms have a microcode update; and we check
this and disable TSC_DEADLINE and print a microcode revision update
error if its too old, we can remove the TSC_ADJUST clamp.
This should help with systems where the second socket runs ahead of
the first socket and needs a negative adjustment. In this case we'd
hit the 0 clamp and give up for not achieving synchronization.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: kevin.b.stanton@intel.com
Link: http://lkml.kernel.org/r/20170531155306.100950003@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/kernel/tsc_sync.c')
| -rw-r--r-- | arch/x86/kernel/tsc_sync.c | 21 |
1 files changed, 1 insertions, 20 deletions
diff --git a/arch/x86/kernel/tsc_sync.c b/arch/x86/kernel/tsc_sync.c index 728f75378475..7842371bc9e4 100644 --- a/arch/x86/kernel/tsc_sync.c +++ b/arch/x86/kernel/tsc_sync.c @@ -71,13 +71,8 @@ static void tsc_sanitize_first_cpu(struct tsc_adjust *cur, s64 bootval, * non zero. We don't do that on non boot cpus because physical * hotplug should have set the ADJUST register to a value > 0 so * the TSC is in sync with the already running cpus. - * - * But we always force positive ADJUST values. Otherwise the TSC - * deadline timer creates an interrupt storm. We also have to - * prevent values > 0x7FFFFFFF as those wreckage the timer as well. */ - if ((bootcpu && bootval != 0) || (!bootcpu && bootval < 0) || - (bootval > 0x7FFFFFFF)) { + if (bootcpu && bootval != 0) { pr_warn(FW_BUG "TSC ADJUST: CPU%u: %lld force to 0\n", cpu, bootval); wrmsrl(MSR_IA32_TSC_ADJUST, 0); @@ -451,20 +446,6 @@ retry: */ cur->adjusted += cur_max_warp; - /* - * TSC deadline timer stops working or creates an interrupt storm - * with adjust values < 0 and > x07ffffff. - * - * To allow adjust values > 0x7FFFFFFF we need to disable the - * deadline timer and use the local APIC timer, but that requires - * more intrusive changes and we do not have any useful information - * from Intel about the underlying HW wreckage yet. - */ - if (cur->adjusted < 0) - cur->adjusted = 0; - if (cur->adjusted > 0x7FFFFFFF) - cur->adjusted = 0x7FFFFFFF; - pr_warn("TSC ADJUST compensate: CPU%u observed %lld warp. Adjust: %lld\n", cpu, cur_max_warp, cur->adjusted); |