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authorLinus Torvalds <torvalds@linux-foundation.org>2018-11-11 16:41:50 -0600
committerLinus Torvalds <torvalds@linux-foundation.org>2018-11-11 16:41:50 -0600
commitb6df7b6db1c1837fc9eada74ed561cbfe7746755 (patch)
treed66f19e700f9c4d5be71005097e3fc558d555d57 /drivers/clocksource
parent655c6b977755594d104d2b87d3e896bd09fd34e8 (diff)
parent15035388439f892017d38b05214d3cda6578af64 (diff)
Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Thomas Gleixner: "A set of x86 fixes: - Cure the LDT remapping to user space on 5 level paging which ended up in the KASLR space - Remove LDT mapping before freeing the LDT pages - Make NFIT MCE handling more robust - Unbreak the VSMP build by removing the dependency on paravirt ops - Support broken PIT emulation on Microsoft hyperV - Don't trace vmware_sched_clock() to avoid tracer recursion - Remove -pipe from KBUILD CFLAGS which breaks clang and is also slower on GCC - Trivial coding style and typo fixes" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/cpu/vmware: Do not trace vmware_sched_clock() x86/vsmp: Remove dependency on pv_irq_ops x86/ldt: Remove unused variable in map_ldt_struct() x86/ldt: Unmap PTEs for the slot before freeing LDT pages x86/mm: Move LDT remap out of KASLR region on 5-level paging acpi/nfit, x86/mce: Validate a MCE's address before using it acpi/nfit, x86/mce: Handle only uncorrectable machine checks x86/build: Remove -pipe from KBUILD_CFLAGS x86/hyper-v: Fix indentation in hv_do_fast_hypercall16() Documentation/x86: Fix typo in zero-page.txt x86/hyper-v: Enable PIT shutdown quirk clockevents/drivers/i8253: Add support for PIT shutdown quirk
Diffstat (limited to 'drivers/clocksource')
-rw-r--r--drivers/clocksource/i8253.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/clocksource/i8253.c b/drivers/clocksource/i8253.c
index 9c38895542f4..d4350bb10b83 100644
--- a/drivers/clocksource/i8253.c
+++ b/drivers/clocksource/i8253.c
@@ -20,6 +20,13 @@
DEFINE_RAW_SPINLOCK(i8253_lock);
EXPORT_SYMBOL(i8253_lock);
+/*
+ * Handle PIT quirk in pit_shutdown() where zeroing the counter register
+ * restarts the PIT, negating the shutdown. On platforms with the quirk,
+ * platform specific code can set this to false.
+ */
+bool i8253_clear_counter_on_shutdown __ro_after_init = true;
+
#ifdef CONFIG_CLKSRC_I8253
/*
* Since the PIT overflows every tick, its not very useful
@@ -109,8 +116,11 @@ static int pit_shutdown(struct clock_event_device *evt)
raw_spin_lock(&i8253_lock);
outb_p(0x30, PIT_MODE);
- outb_p(0, PIT_CH0);
- outb_p(0, PIT_CH0);
+
+ if (i8253_clear_counter_on_shutdown) {
+ outb_p(0, PIT_CH0);
+ outb_p(0, PIT_CH0);
+ }
raw_spin_unlock(&i8253_lock);
return 0;