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-rw-r--r--arch/x86/kernel/tsc_64.c357
1 files changed, 0 insertions, 357 deletions
diff --git a/arch/x86/kernel/tsc_64.c b/arch/x86/kernel/tsc_64.c
deleted file mode 100644
index 1784b8077a12..000000000000
--- a/arch/x86/kernel/tsc_64.c
+++ /dev/null
@@ -1,357 +0,0 @@
1#include <linux/kernel.h>
2#include <linux/sched.h>
3#include <linux/interrupt.h>
4#include <linux/init.h>
5#include <linux/clocksource.h>
6#include <linux/time.h>
7#include <linux/acpi.h>
8#include <linux/cpufreq.h>
9#include <linux/acpi_pmtmr.h>
10
11#include <asm/hpet.h>
12#include <asm/timex.h>
13#include <asm/timer.h>
14#include <asm/vgtod.h>
15
16static int notsc __initdata = 0;
17
18unsigned int cpu_khz; /* TSC clocks / usec, not used here */
19EXPORT_SYMBOL(cpu_khz);
20unsigned int tsc_khz;
21EXPORT_SYMBOL(tsc_khz);
22
23/* Accelerators for sched_clock()
24 * convert from cycles(64bits) => nanoseconds (64bits)
25 * basic equation:
26 * ns = cycles / (freq / ns_per_sec)
27 * ns = cycles * (ns_per_sec / freq)
28 * ns = cycles * (10^9 / (cpu_khz * 10^3))
29 * ns = cycles * (10^6 / cpu_khz)
30 *
31 * Then we use scaling math (suggested by george@mvista.com) to get:
32 * ns = cycles * (10^6 * SC / cpu_khz) / SC
33 * ns = cycles * cyc2ns_scale / SC
34 *
35 * And since SC is a constant power of two, we can convert the div
36 * into a shift.
37 *
38 * We can use khz divisor instead of mhz to keep a better precision, since
39 * cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits.
40 * (mathieu.desnoyers@polymtl.ca)
41 *
42 * -johnstul@us.ibm.com "math is hard, lets go shopping!"
43 */
44DEFINE_PER_CPU(unsigned long, cyc2ns);
45
46static void set_cyc2ns_scale(unsigned long cpu_khz, int cpu)
47{
48 unsigned long long tsc_now, ns_now;
49 unsigned long flags, *scale;
50
51 local_irq_save(flags);
52 sched_clock_idle_sleep_event();
53
54 scale = &per_cpu(cyc2ns, cpu);
55
56 rdtscll(tsc_now);
57 ns_now = __cycles_2_ns(tsc_now);
58
59 if (cpu_khz)
60 *scale = (NSEC_PER_MSEC << CYC2NS_SCALE_FACTOR)/cpu_khz;
61
62 sched_clock_idle_wakeup_event(0);
63 local_irq_restore(flags);
64}
65
66unsigned long long native_sched_clock(void)
67{
68 unsigned long a = 0;
69
70 /* Could do CPU core sync here. Opteron can execute rdtsc speculatively,
71 * which means it is not completely exact and may not be monotonous
72 * between CPUs. But the errors should be too small to matter for
73 * scheduling purposes.
74 */
75
76 rdtscll(a);
77 return cycles_2_ns(a);
78}
79
80/* We need to define a real function for sched_clock, to override the
81 weak default version */
82#ifdef CONFIG_PARAVIRT
83unsigned long long sched_clock(void)
84{
85 return paravirt_sched_clock();
86}
87#else
88unsigned long long
89sched_clock(void) __attribute__((alias("native_sched_clock")));
90#endif
91
92
93static int tsc_unstable;
94
95int check_tsc_unstable(void)
96{
97 return tsc_unstable;
98}
99EXPORT_SYMBOL_GPL(check_tsc_unstable);
100
101#ifdef CONFIG_CPU_FREQ
102
103/* Frequency scaling support. Adjust the TSC based timer when the cpu frequency
104 * changes.
105 *
106 * RED-PEN: On SMP we assume all CPUs run with the same frequency. It's
107 * not that important because current Opteron setups do not support
108 * scaling on SMP anyroads.
109 *
110 * Should fix up last_tsc too. Currently gettimeofday in the
111 * first tick after the change will be slightly wrong.
112 */
113
114static unsigned int ref_freq;
115static unsigned long loops_per_jiffy_ref;
116static unsigned long tsc_khz_ref;
117
118static int time_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
119 void *data)
120{
121 struct cpufreq_freqs *freq = data;
122 unsigned long *lpj, dummy;
123
124 if (cpu_has(&cpu_data(freq->cpu), X86_FEATURE_CONSTANT_TSC))
125 return 0;
126
127 lpj = &dummy;
128 if (!(freq->flags & CPUFREQ_CONST_LOOPS))
129#ifdef CONFIG_SMP
130 lpj = &cpu_data(freq->cpu).loops_per_jiffy;
131#else
132 lpj = &boot_cpu_data.loops_per_jiffy;
133#endif
134
135 if (!ref_freq) {
136 ref_freq = freq->old;
137 loops_per_jiffy_ref = *lpj;
138 tsc_khz_ref = tsc_khz;
139 }
140 if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
141 (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
142 (val == CPUFREQ_RESUMECHANGE)) {
143 *lpj =
144 cpufreq_scale(loops_per_jiffy_ref, ref_freq, freq->new);
145
146 tsc_khz = cpufreq_scale(tsc_khz_ref, ref_freq, freq->new);
147 if (!(freq->flags & CPUFREQ_CONST_LOOPS))
148 mark_tsc_unstable("cpufreq changes");
149 }
150
151 set_cyc2ns_scale(tsc_khz_ref, freq->cpu);
152
153 return 0;
154}
155
156static struct notifier_block time_cpufreq_notifier_block = {
157 .notifier_call = time_cpufreq_notifier
158};
159
160static int __init cpufreq_tsc(void)
161{
162 cpufreq_register_notifier(&time_cpufreq_notifier_block,
163 CPUFREQ_TRANSITION_NOTIFIER);
164 return 0;
165}
166
167core_initcall(cpufreq_tsc);
168
169#endif
170
171#define MAX_RETRIES 5
172#define SMI_TRESHOLD 50000
173
174/*
175 * Read TSC and the reference counters. Take care of SMI disturbance
176 */
177static unsigned long __init tsc_read_refs(unsigned long *pm,
178 unsigned long *hpet)
179{
180 unsigned long t1, t2;
181 int i;
182
183 for (i = 0; i < MAX_RETRIES; i++) {
184 t1 = get_cycles();
185 if (hpet)
186 *hpet = hpet_readl(HPET_COUNTER) & 0xFFFFFFFF;
187 else
188 *pm = acpi_pm_read_early();
189 t2 = get_cycles();
190 if ((t2 - t1) < SMI_TRESHOLD)
191 return t2;
192 }
193 return ULONG_MAX;
194}
195
196/**
197 * tsc_calibrate - calibrate the tsc on boot
198 */
199void __init tsc_calibrate(void)
200{
201 unsigned long flags, tsc1, tsc2, tr1, tr2, pm1, pm2, hpet1, hpet2;
202 int hpet = is_hpet_enabled(), cpu;
203
204 local_irq_save(flags);
205
206 tsc1 = tsc_read_refs(&pm1, hpet ? &hpet1 : NULL);
207
208 outb((inb(0x61) & ~0x02) | 0x01, 0x61);
209
210 outb(0xb0, 0x43);
211 outb((CLOCK_TICK_RATE / (1000 / 50)) & 0xff, 0x42);
212 outb((CLOCK_TICK_RATE / (1000 / 50)) >> 8, 0x42);
213 tr1 = get_cycles();
214 while ((inb(0x61) & 0x20) == 0);
215 tr2 = get_cycles();
216
217 tsc2 = tsc_read_refs(&pm2, hpet ? &hpet2 : NULL);
218
219 local_irq_restore(flags);
220
221 /*
222 * Preset the result with the raw and inaccurate PIT
223 * calibration value
224 */
225 tsc_khz = (tr2 - tr1) / 50;
226
227 /* hpet or pmtimer available ? */
228 if (!hpet && !pm1 && !pm2) {
229 printk(KERN_INFO "TSC calibrated against PIT\n");
230 goto out;
231 }
232
233 /* Check, whether the sampling was disturbed by an SMI */
234 if (tsc1 == ULONG_MAX || tsc2 == ULONG_MAX) {
235 printk(KERN_WARNING "TSC calibration disturbed by SMI, "
236 "using PIT calibration result\n");
237 goto out;
238 }
239
240 tsc2 = (tsc2 - tsc1) * 1000000L;
241
242 if (hpet) {
243 printk(KERN_INFO "TSC calibrated against HPET\n");
244 if (hpet2 < hpet1)
245 hpet2 += 0x100000000;
246 hpet2 -= hpet1;
247 tsc1 = (hpet2 * hpet_readl(HPET_PERIOD)) / 1000000;
248 } else {
249 printk(KERN_INFO "TSC calibrated against PM_TIMER\n");
250 if (pm2 < pm1)
251 pm2 += ACPI_PM_OVRRUN;
252 pm2 -= pm1;
253 tsc1 = (pm2 * 1000000000) / PMTMR_TICKS_PER_SEC;
254 }
255
256 tsc_khz = tsc2 / tsc1;
257
258out:
259 for_each_possible_cpu(cpu)
260 set_cyc2ns_scale(tsc_khz, cpu);
261}
262
263/*
264 * Make an educated guess if the TSC is trustworthy and synchronized
265 * over all CPUs.
266 */
267__cpuinit int unsynchronized_tsc(void)
268{
269 if (tsc_unstable)
270 return 1;
271
272#ifdef CONFIG_SMP
273 if (apic_is_clustered_box())
274 return 1;
275#endif
276
277 if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC))
278 return 0;
279
280 /* Assume multi socket systems are not synchronized */
281 return num_present_cpus() > 1;
282}
283
284int __init notsc_setup(char *s)
285{
286 notsc = 1;
287 return 1;
288}
289
290__setup("notsc", notsc_setup);
291
292static struct clocksource clocksource_tsc;
293
294/*
295 * We compare the TSC to the cycle_last value in the clocksource
296 * structure to avoid a nasty time-warp. This can be observed in a
297 * very small window right after one CPU updated cycle_last under
298 * xtime/vsyscall_gtod lock and the other CPU reads a TSC value which
299 * is smaller than the cycle_last reference value due to a TSC which
300 * is slighty behind. This delta is nowhere else observable, but in
301 * that case it results in a forward time jump in the range of hours
302 * due to the unsigned delta calculation of the time keeping core
303 * code, which is necessary to support wrapping clocksources like pm
304 * timer.
305 */
306static cycle_t read_tsc(void)
307{
308 cycle_t ret = (cycle_t)get_cycles();
309
310 return ret >= clocksource_tsc.cycle_last ?
311 ret : clocksource_tsc.cycle_last;
312}
313
314static cycle_t __vsyscall_fn vread_tsc(void)
315{
316 cycle_t ret = (cycle_t)vget_cycles();
317
318 return ret >= __vsyscall_gtod_data.clock.cycle_last ?
319 ret : __vsyscall_gtod_data.clock.cycle_last;
320}
321
322static struct clocksource clocksource_tsc = {
323 .name = "tsc",
324 .rating = 300,
325 .read = read_tsc,
326 .mask = CLOCKSOURCE_MASK(64),
327 .shift = 22,
328 .flags = CLOCK_SOURCE_IS_CONTINUOUS |
329 CLOCK_SOURCE_MUST_VERIFY,
330 .vread = vread_tsc,
331};
332
333void mark_tsc_unstable(char *reason)
334{
335 if (!tsc_unstable) {
336 tsc_unstable = 1;
337 printk("Marking TSC unstable due to %s\n", reason);
338 /* Change only the rating, when not registered */
339 if (clocksource_tsc.mult)
340 clocksource_change_rating(&clocksource_tsc, 0);
341 else
342 clocksource_tsc.rating = 0;
343 }
344}
345EXPORT_SYMBOL_GPL(mark_tsc_unstable);
346
347void __init init_tsc_clocksource(void)
348{
349 if (!notsc) {
350 clocksource_tsc.mult = clocksource_khz2mult(tsc_khz,
351 clocksource_tsc.shift);
352 if (check_tsc_unstable())
353 clocksource_tsc.rating = 0;
354
355 clocksource_register(&clocksource_tsc);
356 }
357}
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