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-rw-r--r--arch/x86/kernel/tsc_32.c451
1 files changed, 0 insertions, 451 deletions
diff --git a/arch/x86/kernel/tsc_32.c b/arch/x86/kernel/tsc_32.c
deleted file mode 100644
index 65b70637ad97..000000000000
--- a/arch/x86/kernel/tsc_32.c
+++ /dev/null
@@ -1,451 +0,0 @@
1#include <linux/sched.h>
2#include <linux/clocksource.h>
3#include <linux/workqueue.h>
4#include <linux/cpufreq.h>
5#include <linux/jiffies.h>
6#include <linux/init.h>
7#include <linux/dmi.h>
8#include <linux/percpu.h>
9
10#include <asm/delay.h>
11#include <asm/tsc.h>
12#include <asm/io.h>
13#include <asm/timer.h>
14
15#include "mach_timer.h"
16
17/* native_sched_clock() is called before tsc_init(), so
18 we must start with the TSC soft disabled to prevent
19 erroneous rdtsc usage on !cpu_has_tsc processors */
20static int tsc_disabled = -1;
21
22/*
23 * On some systems the TSC frequency does not
24 * change with the cpu frequency. So we need
25 * an extra value to store the TSC freq
26 */
27unsigned int tsc_khz;
28EXPORT_SYMBOL_GPL(tsc_khz);
29
30#ifdef CONFIG_X86_TSC
31static int __init tsc_setup(char *str)
32{
33 printk(KERN_WARNING "notsc: Kernel compiled with CONFIG_X86_TSC, "
34 "cannot disable TSC completely.\n");
35 tsc_disabled = 1;
36 return 1;
37}
38#else
39/*
40 * disable flag for tsc. Takes effect by clearing the TSC cpu flag
41 * in cpu/common.c
42 */
43static int __init tsc_setup(char *str)
44{
45 setup_clear_cpu_cap(X86_FEATURE_TSC);
46 return 1;
47}
48#endif
49
50__setup("notsc", tsc_setup);
51
52/*
53 * code to mark and check if the TSC is unstable
54 * due to cpufreq or due to unsynced TSCs
55 */
56static int tsc_unstable;
57
58int check_tsc_unstable(void)
59{
60 return tsc_unstable;
61}
62EXPORT_SYMBOL_GPL(check_tsc_unstable);
63
64/* Accelerators for sched_clock()
65 * convert from cycles(64bits) => nanoseconds (64bits)
66 * basic equation:
67 * ns = cycles / (freq / ns_per_sec)
68 * ns = cycles * (ns_per_sec / freq)
69 * ns = cycles * (10^9 / (cpu_khz * 10^3))
70 * ns = cycles * (10^6 / cpu_khz)
71 *
72 * Then we use scaling math (suggested by george@mvista.com) to get:
73 * ns = cycles * (10^6 * SC / cpu_khz) / SC
74 * ns = cycles * cyc2ns_scale / SC
75 *
76 * And since SC is a constant power of two, we can convert the div
77 * into a shift.
78 *
79 * We can use khz divisor instead of mhz to keep a better precision, since
80 * cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits.
81 * (mathieu.desnoyers@polymtl.ca)
82 *
83 * -johnstul@us.ibm.com "math is hard, lets go shopping!"
84 */
85
86DEFINE_PER_CPU(unsigned long, cyc2ns);
87
88static void set_cyc2ns_scale(unsigned long cpu_khz, int cpu)
89{
90 unsigned long long tsc_now, ns_now;
91 unsigned long flags, *scale;
92
93 local_irq_save(flags);
94 sched_clock_idle_sleep_event();
95
96 scale = &per_cpu(cyc2ns, cpu);
97
98 rdtscll(tsc_now);
99 ns_now = __cycles_2_ns(tsc_now);
100
101 if (cpu_khz)
102 *scale = (NSEC_PER_MSEC << CYC2NS_SCALE_FACTOR)/cpu_khz;
103
104 /*
105 * Start smoothly with the new frequency:
106 */
107 sched_clock_idle_wakeup_event(0);
108 local_irq_restore(flags);
109}
110
111/*
112 * Scheduler clock - returns current time in nanosec units.
113 */
114unsigned long long native_sched_clock(void)
115{
116 unsigned long long this_offset;
117
118 /*
119 * Fall back to jiffies if there's no TSC available:
120 * ( But note that we still use it if the TSC is marked
121 * unstable. We do this because unlike Time Of Day,
122 * the scheduler clock tolerates small errors and it's
123 * very important for it to be as fast as the platform
124 * can achive it. )
125 */
126 if (unlikely(tsc_disabled))
127 /* No locking but a rare wrong value is not a big deal: */
128 return (jiffies_64 - INITIAL_JIFFIES) * (1000000000 / HZ);
129
130 /* read the Time Stamp Counter: */
131 rdtscll(this_offset);
132
133 /* return the value in ns */
134 return cycles_2_ns(this_offset);
135}
136
137/* We need to define a real function for sched_clock, to override the
138 weak default version */
139#ifdef CONFIG_PARAVIRT
140unsigned long long sched_clock(void)
141{
142 return paravirt_sched_clock();
143}
144#else
145unsigned long long sched_clock(void)
146 __attribute__((alias("native_sched_clock")));
147#endif
148
149unsigned long native_calculate_cpu_khz(void)
150{
151 unsigned long long start, end;
152 unsigned long count;
153 u64 delta64 = (u64)ULLONG_MAX;
154 int i;
155 unsigned long flags;
156
157 local_irq_save(flags);
158
159 /* run 3 times to ensure the cache is warm and to get an accurate reading */
160 for (i = 0; i < 3; i++) {
161 mach_prepare_counter();
162 rdtscll(start);
163 mach_countup(&count);
164 rdtscll(end);
165
166 /*
167 * Error: ECTCNEVERSET
168 * The CTC wasn't reliable: we got a hit on the very first read,
169 * or the CPU was so fast/slow that the quotient wouldn't fit in
170 * 32 bits..
171 */
172 if (count <= 1)
173 continue;
174
175 /* cpu freq too slow: */
176 if ((end - start) <= CALIBRATE_TIME_MSEC)
177 continue;
178
179 /*
180 * We want the minimum time of all runs in case one of them
181 * is inaccurate due to SMI or other delay
182 */
183 delta64 = min(delta64, (end - start));
184 }
185
186 /* cpu freq too fast (or every run was bad): */
187 if (delta64 > (1ULL<<32))
188 goto err;
189
190 delta64 += CALIBRATE_TIME_MSEC/2; /* round for do_div */
191 do_div(delta64,CALIBRATE_TIME_MSEC);
192
193 local_irq_restore(flags);
194 return (unsigned long)delta64;
195err:
196 local_irq_restore(flags);
197 return 0;
198}
199
200int recalibrate_cpu_khz(void)
201{
202#ifndef CONFIG_SMP
203 unsigned long cpu_khz_old = cpu_khz;
204
205 if (cpu_has_tsc) {
206 cpu_khz = calculate_cpu_khz();
207 tsc_khz = cpu_khz;
208 cpu_data(0).loops_per_jiffy =
209 cpufreq_scale(cpu_data(0).loops_per_jiffy,
210 cpu_khz_old, cpu_khz);
211 return 0;
212 } else
213 return -ENODEV;
214#else
215 return -ENODEV;
216#endif
217}
218
219EXPORT_SYMBOL(recalibrate_cpu_khz);
220
221#ifdef CONFIG_CPU_FREQ
222
223/*
224 * if the CPU frequency is scaled, TSC-based delays will need a different
225 * loops_per_jiffy value to function properly.
226 */
227static unsigned int ref_freq;
228static unsigned long loops_per_jiffy_ref;
229static unsigned long cpu_khz_ref;
230
231static int
232time_cpufreq_notifier(struct notifier_block *nb, unsigned long val, void *data)
233{
234 struct cpufreq_freqs *freq = data;
235
236 if (!ref_freq) {
237 if (!freq->old){
238 ref_freq = freq->new;
239 return 0;
240 }
241 ref_freq = freq->old;
242 loops_per_jiffy_ref = cpu_data(freq->cpu).loops_per_jiffy;
243 cpu_khz_ref = cpu_khz;
244 }
245
246 if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
247 (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
248 (val == CPUFREQ_RESUMECHANGE)) {
249 if (!(freq->flags & CPUFREQ_CONST_LOOPS))
250 cpu_data(freq->cpu).loops_per_jiffy =
251 cpufreq_scale(loops_per_jiffy_ref,
252 ref_freq, freq->new);
253
254 if (cpu_khz) {
255
256 if (num_online_cpus() == 1)
257 cpu_khz = cpufreq_scale(cpu_khz_ref,
258 ref_freq, freq->new);
259 if (!(freq->flags & CPUFREQ_CONST_LOOPS)) {
260 tsc_khz = cpu_khz;
261 set_cyc2ns_scale(cpu_khz, freq->cpu);
262 /*
263 * TSC based sched_clock turns
264 * to junk w/ cpufreq
265 */
266 mark_tsc_unstable("cpufreq changes");
267 }
268 }
269 }
270
271 return 0;
272}
273
274static struct notifier_block time_cpufreq_notifier_block = {
275 .notifier_call = time_cpufreq_notifier
276};
277
278static int __init cpufreq_tsc(void)
279{
280 return cpufreq_register_notifier(&time_cpufreq_notifier_block,
281 CPUFREQ_TRANSITION_NOTIFIER);
282}
283core_initcall(cpufreq_tsc);
284
285#endif
286
287/* clock source code */
288
289static unsigned long current_tsc_khz;
290static struct clocksource clocksource_tsc;
291
292/*
293 * We compare the TSC to the cycle_last value in the clocksource
294 * structure to avoid a nasty time-warp issue. This can be observed in
295 * a very small window right after one CPU updated cycle_last under
296 * xtime lock and the other CPU reads a TSC value which is smaller
297 * than the cycle_last reference value due to a TSC which is slighty
298 * behind. This delta is nowhere else observable, but in that case it
299 * results in a forward time jump in the range of hours due to the
300 * unsigned delta calculation of the time keeping core code, which is
301 * necessary to support wrapping clocksources like pm timer.
302 */
303static cycle_t read_tsc(void)
304{
305 cycle_t ret;
306
307 rdtscll(ret);
308
309 return ret >= clocksource_tsc.cycle_last ?
310 ret : clocksource_tsc.cycle_last;
311}
312
313static struct clocksource clocksource_tsc = {
314 .name = "tsc",
315 .rating = 300,
316 .read = read_tsc,
317 .mask = CLOCKSOURCE_MASK(64),
318 .mult = 0, /* to be set */
319 .shift = 22,
320 .flags = CLOCK_SOURCE_IS_CONTINUOUS |
321 CLOCK_SOURCE_MUST_VERIFY,
322};
323
324void mark_tsc_unstable(char *reason)
325{
326 if (!tsc_unstable) {
327 tsc_unstable = 1;
328 printk("Marking TSC unstable due to: %s.\n", reason);
329 /* Can be called before registration */
330 if (clocksource_tsc.mult)
331 clocksource_change_rating(&clocksource_tsc, 0);
332 else
333 clocksource_tsc.rating = 0;
334 }
335}
336EXPORT_SYMBOL_GPL(mark_tsc_unstable);
337
338static int __init dmi_mark_tsc_unstable(const struct dmi_system_id *d)
339{
340 printk(KERN_NOTICE "%s detected: marking TSC unstable.\n",
341 d->ident);
342 tsc_unstable = 1;
343 return 0;
344}
345
346/* List of systems that have known TSC problems */
347static struct dmi_system_id __initdata bad_tsc_dmi_table[] = {
348 {
349 .callback = dmi_mark_tsc_unstable,
350 .ident = "IBM Thinkpad 380XD",
351 .matches = {
352 DMI_MATCH(DMI_BOARD_VENDOR, "IBM"),
353 DMI_MATCH(DMI_BOARD_NAME, "2635FA0"),
354 },
355 },
356 {}
357};
358
359/*
360 * Make an educated guess if the TSC is trustworthy and synchronized
361 * over all CPUs.
362 */
363__cpuinit int unsynchronized_tsc(void)
364{
365 if (!cpu_has_tsc || tsc_unstable)
366 return 1;
367
368 /* Anything with constant TSC should be synchronized */
369 if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC))
370 return 0;
371
372 /*
373 * Intel systems are normally all synchronized.
374 * Exceptions must mark TSC as unstable:
375 */
376 if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) {
377 /* assume multi socket systems are not synchronized: */
378 if (num_possible_cpus() > 1)
379 tsc_unstable = 1;
380 }
381 return tsc_unstable;
382}
383
384/*
385 * Geode_LX - the OLPC CPU has a possibly a very reliable TSC
386 */
387#ifdef CONFIG_MGEODE_LX
388/* RTSC counts during suspend */
389#define RTSC_SUSP 0x100
390
391static void __init check_geode_tsc_reliable(void)
392{
393 unsigned long res_low, res_high;
394
395 rdmsr_safe(MSR_GEODE_BUSCONT_CONF0, &res_low, &res_high);
396 if (res_low & RTSC_SUSP)
397 clocksource_tsc.flags &= ~CLOCK_SOURCE_MUST_VERIFY;
398}
399#else
400static inline void check_geode_tsc_reliable(void) { }
401#endif
402
403
404void __init tsc_init(void)
405{
406 int cpu;
407
408 if (!cpu_has_tsc || tsc_disabled > 0)
409 return;
410
411 cpu_khz = calculate_cpu_khz();
412 tsc_khz = cpu_khz;
413
414 if (!cpu_khz) {
415 mark_tsc_unstable("could not calculate TSC khz");
416 return;
417 }
418
419 /* now allow native_sched_clock() to use rdtsc */
420 tsc_disabled = 0;
421
422 printk("Detected %lu.%03lu MHz processor.\n",
423 (unsigned long)cpu_khz / 1000,
424 (unsigned long)cpu_khz % 1000);
425
426 /*
427 * Secondary CPUs do not run through tsc_init(), so set up
428 * all the scale factors for all CPUs, assuming the same
429 * speed as the bootup CPU. (cpufreq notifiers will fix this
430 * up if their speed diverges)
431 */
432 for_each_possible_cpu(cpu)
433 set_cyc2ns_scale(cpu_khz, cpu);
434
435 use_tsc_delay();
436
437 /* Check and install the TSC clocksource */
438 dmi_check_system(bad_tsc_dmi_table);
439
440 unsynchronized_tsc();
441 check_geode_tsc_reliable();
442 current_tsc_khz = tsc_khz;
443 clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
444 clocksource_tsc.shift);
445 /* lower the rating if we already know its unstable: */
446 if (check_tsc_unstable()) {
447 clocksource_tsc.rating = 0;
448 clocksource_tsc.flags &= ~CLOCK_SOURCE_IS_CONTINUOUS;
449 }
450 clocksource_register(&clocksource_tsc);
451}
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