Merge branch 'x86-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 timers updates from Thomas Gleixner:
 "This update contains:

   - The solution for the TSC deadline timer borkage, which is caused by
     a hardware problem in the TSC_ADJUST/TSC_DEADLINE_TIMER logic.

     The problem is documented now and fixed with a microcode update, so
     we can remove the workaround and just check for the microcode version.

     If the microcode is not up to date, then the TSC deadline timer is
     disabled. If the borkage is fixed by the proper microcode version,
     then the deadline timer can be used. In both cases the restrictions
     to the range of the TSC_ADJUST value, which were added as
     workarounds, are removed.

  - A few simple fixes and updates to the timer related x86 code"

* 'x86-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/tsc: Call check_system_tsc_reliable() before unsynchronized_tsc()
  x86/hpet: Do not use smp_processor_id() in preemptible code
  x86/time: Make setup_default_timer_irq() static
  x86/tsc: Remove the TSC_ADJUST clamp
  x86/apic: Add TSC_DEADLINE quirk due to errata
  x86/apic: Change the lapic name in deadline mode

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);