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-rw-r--r--arch/x86_64/kernel/tsc_sync.c187
1 files changed, 0 insertions, 187 deletions
diff --git a/arch/x86_64/kernel/tsc_sync.c b/arch/x86_64/kernel/tsc_sync.c
deleted file mode 100644
index 355f5f506c8..00000000000
--- a/arch/x86_64/kernel/tsc_sync.c
+++ /dev/null
@@ -1,187 +0,0 @@
-/*
- * arch/x86_64/kernel/tsc_sync.c: 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_sync();
- /*
- * 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_sync();
- 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 100 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 > 100000000)
- 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);
- }
-
- }
-}
-
-/*
- * 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();
-
- /*
- * Reset it - just in case we boot another CPU later:
- */
- atomic_set(&start_count, 0);
-
- 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");
- nr_warps = 0;
- max_warp = 0;
- last_tsc = 0;
- } else {
- printk(" passed.\n");
- }
-
- /*
- * 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
-