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Date: Mon, 29 Jan 2018 09:57:11 +0100 (CET)
From: Thomas Gleixner <tglx@...utronix.de>
To: Linus Torvalds <torvalds@...ux-foundation.org>
cc: LKML <linux-kernel@...r.kernel.org>, Ingo Molnar <mingo@...nel.org>
Subject: [GIT pull] x86/timer updates for 4.16
Linus,
please pull the latest x86-timers-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-timers-for-linus
A small set of updates for x86 specific timers:
- Mark TSC invariant on a subset of Centaur CPUs
- Allow TSC calibration without PIT on mobile platforms which lack legacy
devices.
Thanks,
tglx
------------------>
Peter Zijlstra (3):
x86/tsc: Allow TSC calibration without PIT
x86/time: Unconditionally register legacy timer interrupt
x86/tsc: Introduce early tsc clocksource
davidwang (1):
x86/centaur: Mark TSC invariant
arch/x86/include/asm/i8259.h | 5 ++++
arch/x86/kernel/cpu/centaur.c | 4 +++
arch/x86/kernel/time.c | 9 ++++---
arch/x86/kernel/tsc.c | 61 ++++++++++++++++++++++++++++++++++++-------
drivers/acpi/processor_idle.c | 1 +
5 files changed, 67 insertions(+), 13 deletions(-)
diff --git a/arch/x86/include/asm/i8259.h b/arch/x86/include/asm/i8259.h
index c8376b40e882..5cdcdbd4d892 100644
--- a/arch/x86/include/asm/i8259.h
+++ b/arch/x86/include/asm/i8259.h
@@ -69,6 +69,11 @@ struct legacy_pic {
extern struct legacy_pic *legacy_pic;
extern struct legacy_pic null_legacy_pic;
+static inline bool has_legacy_pic(void)
+{
+ return legacy_pic != &null_legacy_pic;
+}
+
static inline int nr_legacy_irqs(void)
{
return legacy_pic->nr_legacy_irqs;
diff --git a/arch/x86/kernel/cpu/centaur.c b/arch/x86/kernel/cpu/centaur.c
index 68bc6d9b3132..c578cd29c2d2 100644
--- a/arch/x86/kernel/cpu/centaur.c
+++ b/arch/x86/kernel/cpu/centaur.c
@@ -106,6 +106,10 @@ static void early_init_centaur(struct cpuinfo_x86 *c)
#ifdef CONFIG_X86_64
set_cpu_cap(c, X86_FEATURE_SYSENTER32);
#endif
+ if (c->x86_power & (1 << 8)) {
+ set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
+ set_cpu_cap(c, X86_FEATURE_NONSTOP_TSC);
+ }
}
static void init_centaur(struct cpuinfo_x86 *c)
diff --git a/arch/x86/kernel/time.c b/arch/x86/kernel/time.c
index 749d189f8cd4..774ebafa97c4 100644
--- a/arch/x86/kernel/time.c
+++ b/arch/x86/kernel/time.c
@@ -69,9 +69,12 @@ static struct irqaction irq0 = {
static void __init setup_default_timer_irq(void)
{
- if (!nr_legacy_irqs())
- return;
- setup_irq(0, &irq0);
+ /*
+ * Unconditionally register the legacy timer; even without legacy
+ * PIC/PIT we need this for the HPET0 in legacy replacement mode.
+ */
+ if (setup_irq(0, &irq0))
+ pr_info("Failed to register legacy timer interrupt\n");
}
/* Default timer init function */
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index e169e85db434..fb4302738410 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -25,6 +25,7 @@
#include <asm/geode.h>
#include <asm/apic.h>
#include <asm/intel-family.h>
+#include <asm/i8259.h>
unsigned int __read_mostly cpu_khz; /* TSC clocks / usec, not used here */
EXPORT_SYMBOL(cpu_khz);
@@ -363,6 +364,20 @@ static unsigned long pit_calibrate_tsc(u32 latch, unsigned long ms, int loopmin)
unsigned long tscmin, tscmax;
int pitcnt;
+ if (!has_legacy_pic()) {
+ /*
+ * Relies on tsc_early_delay_calibrate() to have given us semi
+ * usable udelay(), wait for the same 50ms we would have with
+ * the PIT loop below.
+ */
+ udelay(10 * USEC_PER_MSEC);
+ udelay(10 * USEC_PER_MSEC);
+ udelay(10 * USEC_PER_MSEC);
+ udelay(10 * USEC_PER_MSEC);
+ udelay(10 * USEC_PER_MSEC);
+ return ULONG_MAX;
+ }
+
/* Set the Gate high, disable speaker */
outb((inb(0x61) & ~0x02) | 0x01, 0x61);
@@ -487,6 +502,9 @@ static unsigned long quick_pit_calibrate(void)
u64 tsc, delta;
unsigned long d1, d2;
+ if (!has_legacy_pic())
+ return 0;
+
/* Set the Gate high, disable speaker */
outb((inb(0x61) & ~0x02) | 0x01, 0x61);
@@ -988,8 +1006,6 @@ static void __init detect_art(void)
/* clocksource code */
-static struct clocksource clocksource_tsc;
-
static void tsc_resume(struct clocksource *cs)
{
tsc_verify_tsc_adjust(true);
@@ -1040,12 +1056,31 @@ static void tsc_cs_tick_stable(struct clocksource *cs)
/*
* .mask MUST be CLOCKSOURCE_MASK(64). See comment above read_tsc()
*/
+static struct clocksource clocksource_tsc_early = {
+ .name = "tsc-early",
+ .rating = 299,
+ .read = read_tsc,
+ .mask = CLOCKSOURCE_MASK(64),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS |
+ CLOCK_SOURCE_MUST_VERIFY,
+ .archdata = { .vclock_mode = VCLOCK_TSC },
+ .resume = tsc_resume,
+ .mark_unstable = tsc_cs_mark_unstable,
+ .tick_stable = tsc_cs_tick_stable,
+};
+
+/*
+ * Must mark VALID_FOR_HRES early such that when we unregister tsc_early
+ * this one will immediately take over. We will only register if TSC has
+ * been found good.
+ */
static struct clocksource clocksource_tsc = {
.name = "tsc",
.rating = 300,
.read = read_tsc,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS |
+ CLOCK_SOURCE_VALID_FOR_HRES |
CLOCK_SOURCE_MUST_VERIFY,
.archdata = { .vclock_mode = VCLOCK_TSC },
.resume = tsc_resume,
@@ -1169,8 +1204,8 @@ static void tsc_refine_calibration_work(struct work_struct *work)
int cpu;
/* Don't bother refining TSC on unstable systems */
- if (check_tsc_unstable())
- goto out;
+ if (tsc_unstable)
+ return;
/*
* Since the work is started early in boot, we may be
@@ -1222,9 +1257,13 @@ static void tsc_refine_calibration_work(struct work_struct *work)
set_cyc2ns_scale(tsc_khz, cpu, tsc_stop);
out:
+ if (tsc_unstable)
+ return;
+
if (boot_cpu_has(X86_FEATURE_ART))
art_related_clocksource = &clocksource_tsc;
clocksource_register_khz(&clocksource_tsc, tsc_khz);
+ clocksource_unregister(&clocksource_tsc_early);
}
@@ -1233,13 +1272,11 @@ static int __init init_tsc_clocksource(void)
if (!boot_cpu_has(X86_FEATURE_TSC) || tsc_disabled > 0 || !tsc_khz)
return 0;
+ if (check_tsc_unstable())
+ return 0;
+
if (tsc_clocksource_reliable)
clocksource_tsc.flags &= ~CLOCK_SOURCE_MUST_VERIFY;
- /* lower the rating if we already know its unstable: */
- if (check_tsc_unstable()) {
- clocksource_tsc.rating = 0;
- clocksource_tsc.flags &= ~CLOCK_SOURCE_IS_CONTINUOUS;
- }
if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC_S3))
clocksource_tsc.flags |= CLOCK_SOURCE_SUSPEND_NONSTOP;
@@ -1252,6 +1289,7 @@ static int __init init_tsc_clocksource(void)
if (boot_cpu_has(X86_FEATURE_ART))
art_related_clocksource = &clocksource_tsc;
clocksource_register_khz(&clocksource_tsc, tsc_khz);
+ clocksource_unregister(&clocksource_tsc_early);
return 0;
}
@@ -1356,9 +1394,12 @@ void __init tsc_init(void)
check_system_tsc_reliable();
- if (unsynchronized_tsc())
+ if (unsynchronized_tsc()) {
mark_tsc_unstable("TSCs unsynchronized");
+ return;
+ }
+ clocksource_register_khz(&clocksource_tsc_early, tsc_khz);
detect_art();
}
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index d50a7b6ccddd..5f0071c7e2e1 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -207,6 +207,7 @@ static void tsc_check_state(int state)
switch (boot_cpu_data.x86_vendor) {
case X86_VENDOR_AMD:
case X86_VENDOR_INTEL:
+ case X86_VENDOR_CENTAUR:
/*
* AMD Fam10h TSC will tick in all
* C/P/S0/S1 states when this bit is set.
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