projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 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 |