Commit | Line | Data |
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2272b0e0 AS |
1 | /* |
2 | * linux/include/asm-i386/tsc.h | |
3 | * | |
4 | * i386 TSC related functions | |
5 | */ | |
6 | #ifndef _ASM_i386_TSC_H | |
7 | #define _ASM_i386_TSC_H | |
8 | ||
9 | #include <asm/processor.h> | |
10 | ||
11 | /* | |
12 | * Standard way to access the cycle counter. | |
13 | */ | |
14 | typedef unsigned long long cycles_t; | |
15 | ||
16 | extern unsigned int cpu_khz; | |
17 | extern unsigned int tsc_khz; | |
18 | ||
19 | static inline cycles_t get_cycles(void) | |
20 | { | |
21 | unsigned long long ret = 0; | |
22 | ||
23 | #ifndef CONFIG_X86_TSC | |
24 | if (!cpu_has_tsc) | |
25 | return 0; | |
26 | #endif | |
27 | ||
28 | #if defined(CONFIG_X86_GENERIC) || defined(CONFIG_X86_TSC) | |
29 | rdtscll(ret); | |
30 | #endif | |
31 | return ret; | |
32 | } | |
33 | ||
34 | /* Like get_cycles, but make sure the CPU is synchronized. */ | |
35 | static __always_inline cycles_t get_cycles_sync(void) | |
36 | { | |
37 | unsigned long long ret; | |
2272b0e0 AS |
38 | unsigned eax; |
39 | ||
c5bcb563 AK |
40 | /* |
41 | * Use RDTSCP if possible; it is guaranteed to be synchronous | |
42 | * and doesn't cause a VMEXIT on Hypervisors | |
43 | */ | |
44 | alternative_io(ASM_NOP3, ".byte 0x0f,0x01,0xf9", X86_FEATURE_RDTSCP, | |
45 | "=A" (ret), "0" (0ULL) : "ecx", "memory"); | |
46 | if (ret) | |
47 | return ret; | |
48 | ||
2272b0e0 AS |
49 | /* |
50 | * Don't do an additional sync on CPUs where we know | |
51 | * RDTSC is already synchronous: | |
52 | */ | |
53 | alternative_io("cpuid", ASM_NOP2, X86_FEATURE_SYNC_RDTSC, | |
54 | "=a" (eax), "0" (1) : "ebx","ecx","edx","memory"); | |
2272b0e0 AS |
55 | rdtscll(ret); |
56 | ||
57 | return ret; | |
58 | } | |
59 | ||
60 | extern void tsc_init(void); | |
5a90cf20 | 61 | extern void mark_tsc_unstable(char *reason); |
2272b0e0 AS |
62 | extern int unsynchronized_tsc(void); |
63 | extern void init_tsc_clocksource(void); | |
64 | ||
65 | /* | |
66 | * Boot-time check whether the TSCs are synchronized across | |
67 | * all CPUs/cores: | |
68 | */ | |
69 | extern void check_tsc_sync_source(int cpu); | |
70 | extern void check_tsc_sync_target(void); | |
71 | ||
72 | #endif |