[patch 12/17] x86 : remove arch-specific tsc_sync.c
From: Mathieu Desnoyers
Date: Wed Nov 12 2008 - 18:39:25 EST
Depends on the new arch. independent kernel/time/tsc-sync.c
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>
CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CC: Ingo Molnar <mingo@xxxxxxxxxx>
CC: H. Peter Anvin <hpa@xxxxxxxxx>
CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
CC: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
CC: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
arch/x86/Kconfig | 2
arch/x86/include/asm/tsc.h | 8 +
arch/x86/kernel/Makefile | 4
arch/x86/kernel/tsc_sync.c | 189 ---------------------------------------------
4 files changed, 11 insertions(+), 192 deletions(-)
Index: linux.trees.git/arch/x86/kernel/Makefile
===================================================================
--- linux.trees.git.orig/arch/x86/kernel/Makefile 2008-11-12 18:14:22.000000000 -0500
+++ linux.trees.git/arch/x86/kernel/Makefile 2008-11-12 18:15:37.000000000 -0500
@@ -56,9 +56,9 @@ obj-$(CONFIG_PCI) += early-quirks.o
apm-y := apm_32.o
obj-$(CONFIG_APM) += apm.o
obj-$(CONFIG_X86_SMP) += smp.o
-obj-$(CONFIG_X86_SMP) += smpboot.o tsc_sync.o ipi.o tlb_$(BITS).o
+obj-$(CONFIG_X86_SMP) += smpboot.o ipi.o tlb_$(BITS).o
obj-$(CONFIG_X86_32_SMP) += smpcommon.o
-obj-$(CONFIG_X86_64_SMP) += tsc_sync.o smpcommon.o
+obj-$(CONFIG_X86_64_SMP) += smpcommon.o
obj-$(CONFIG_X86_TRAMPOLINE) += trampoline_$(BITS).o
obj-$(CONFIG_X86_MPPARSE) += mpparse.o
obj-$(CONFIG_X86_LOCAL_APIC) += apic.o nmi.o
Index: linux.trees.git/arch/x86/kernel/tsc_sync.c
===================================================================
--- linux.trees.git.orig/arch/x86/kernel/tsc_sync.c 2008-11-12 18:14:22.000000000 -0500
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,189 +0,0 @@
-/*
- * check TSC synchronization.
- *
- * Copyright (C) 2006, Red Hat, Inc., Ingo Molnar
- *
- * We check whether all boot CPUs have their TSC's synchronized,
- * print a warning if not and turn off the TSC clock-source.
- *
- * The warp-check is point-to-point between two CPUs, the CPU
- * initiating the bootup is the 'source CPU', the freshly booting
- * CPU is the 'target CPU'.
- *
- * Only two CPUs may participate - they can enter in any order.
- * ( The serial nature of the boot logic and the CPU hotplug lock
- * protects against more than 2 CPUs entering this code. )
- */
-#include <linux/spinlock.h>
-#include <linux/kernel.h>
-#include <linux/init.h>
-#include <linux/smp.h>
-#include <linux/nmi.h>
-#include <asm/tsc.h>
-
-/*
- * Entry/exit counters that make sure that both CPUs
- * run the measurement code at once:
- */
-static __cpuinitdata atomic_t start_count;
-static __cpuinitdata atomic_t stop_count;
-
-/*
- * We use a raw spinlock in this exceptional case, because
- * we want to have the fastest, inlined, non-debug version
- * of a critical section, to be able to prove TSC time-warps:
- */
-static __cpuinitdata raw_spinlock_t sync_lock = __RAW_SPIN_LOCK_UNLOCKED;
-static __cpuinitdata cycles_t last_tsc;
-static __cpuinitdata cycles_t max_warp;
-static __cpuinitdata int nr_warps;
-
-/*
- * TSC-warp measurement loop running on both CPUs:
- */
-static __cpuinit void check_tsc_warp(void)
-{
- cycles_t start, now, prev, end;
- int i;
-
- start = get_cycles();
- /*
- * The measurement runs for 20 msecs:
- */
- end = start + tsc_khz * 20ULL;
- now = start;
-
- for (i = 0; ; i++) {
- /*
- * We take the global lock, measure TSC, save the
- * previous TSC that was measured (possibly on
- * another CPU) and update the previous TSC timestamp.
- */
- __raw_spin_lock(&sync_lock);
- prev = last_tsc;
- now = get_cycles();
- last_tsc = now;
- __raw_spin_unlock(&sync_lock);
-
- /*
- * Be nice every now and then (and also check whether
- * measurement is done [we also insert a 10 million
- * loops safety exit, so we dont lock up in case the
- * TSC readout is totally broken]):
- */
- if (unlikely(!(i & 7))) {
- if (now > end || i > 10000000)
- break;
- cpu_relax();
- touch_nmi_watchdog();
- }
- /*
- * Outside the critical section we can now see whether
- * we saw a time-warp of the TSC going backwards:
- */
- if (unlikely(prev > now)) {
- __raw_spin_lock(&sync_lock);
- max_warp = max(max_warp, prev - now);
- nr_warps++;
- __raw_spin_unlock(&sync_lock);
- }
- }
- WARN(!(now-start),
- "Warning: zero tsc calibration delta: %Ld [max: %Ld]\n",
- now-start, end-start);
-}
-
-/*
- * Source CPU calls into this - it waits for the freshly booted
- * target CPU to arrive and then starts the measurement:
- */
-void __cpuinit check_tsc_sync_source(int cpu)
-{
- int cpus = 2;
-
- /*
- * No need to check if we already know that the TSC is not
- * synchronized:
- */
- if (unsynchronized_tsc())
- return;
-
- printk(KERN_INFO "checking TSC synchronization [CPU#%d -> CPU#%d]:",
- smp_processor_id(), cpu);
-
- /*
- * Reset it - in case this is a second bootup:
- */
- atomic_set(&stop_count, 0);
-
- /*
- * Wait for the target to arrive:
- */
- while (atomic_read(&start_count) != cpus-1)
- cpu_relax();
- /*
- * Trigger the target to continue into the measurement too:
- */
- atomic_inc(&start_count);
-
- check_tsc_warp();
-
- while (atomic_read(&stop_count) != cpus-1)
- cpu_relax();
-
- if (nr_warps) {
- printk("\n");
- printk(KERN_WARNING "Measured %Ld cycles TSC warp between CPUs,"
- " turning off TSC clock.\n", max_warp);
- mark_tsc_unstable("check_tsc_sync_source failed");
- } else {
- printk(" passed.\n");
- }
-
- /*
- * Reset it - just in case we boot another CPU later:
- */
- atomic_set(&start_count, 0);
- nr_warps = 0;
- max_warp = 0;
- last_tsc = 0;
-
- /*
- * Let the target continue with the bootup:
- */
- atomic_inc(&stop_count);
-}
-
-/*
- * Freshly booted CPUs call into this:
- */
-void __cpuinit check_tsc_sync_target(void)
-{
- int cpus = 2;
-
- if (unsynchronized_tsc())
- return;
-
- /*
- * Register this CPU's participation and wait for the
- * source CPU to start the measurement:
- */
- atomic_inc(&start_count);
- while (atomic_read(&start_count) != cpus)
- cpu_relax();
-
- check_tsc_warp();
-
- /*
- * Ok, we are done:
- */
- atomic_inc(&stop_count);
-
- /*
- * Wait for the source CPU to print stuff:
- */
- while (atomic_read(&stop_count) != cpus)
- cpu_relax();
-}
-#undef NR_LOOPS
-
Index: linux.trees.git/arch/x86/Kconfig
===================================================================
--- linux.trees.git.orig/arch/x86/Kconfig 2008-11-12 18:15:28.000000000 -0500
+++ linux.trees.git/arch/x86/Kconfig 2008-11-12 18:15:37.000000000 -0500
@@ -169,6 +169,7 @@ config X86_SMP
bool
depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64)
select USE_GENERIC_SMP_HELPERS
+ select HAVE_UNSYNCHRONIZED_TSC
default y
config X86_32_SMP
@@ -178,6 +179,7 @@ config X86_32_SMP
config X86_64_SMP
def_bool y
depends on X86_64 && SMP
+ select HAVE_UNSYNCHRONIZED_TSC
config X86_HT
bool
Index: linux.trees.git/arch/x86/include/asm/tsc.h
===================================================================
--- linux.trees.git.orig/arch/x86/include/asm/tsc.h 2008-11-12 18:15:28.000000000 -0500
+++ linux.trees.git/arch/x86/include/asm/tsc.h 2008-11-12 18:15:37.000000000 -0500
@@ -54,7 +54,7 @@ static __always_inline cycles_t vget_cyc
extern void tsc_init(void);
extern void mark_tsc_unstable(char *reason);
extern int unsynchronized_tsc(void);
-int check_tsc_unstable(void);
+extern int check_tsc_unstable(void);
static inline cycles_t get_cycles_rate(void)
{
@@ -77,4 +77,10 @@ extern void check_tsc_sync_target(void);
extern int notsc_setup(char *);
+extern int test_tsc_synchronization(void);
+extern int _tsc_is_sync;
+static inline int tsc_is_sync(void)
+{
+ return _tsc_is_sync;
+}
#endif /* _ASM_X86_TSC_H */
--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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