X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=include%2Fasm-i386%2Ftsc.h;h=a4d806610b7ff5c56dc51a628ca8f20ad73d1c89;hb=d7e28ffe6c74416b54345d6004fd0964c115b12c;hp=e997891cc7cc8bfdedf6b9447996e291e5b0a9b1;hpb=902b236c087bf021c94cc21a2b09d928c4156c2b;p=~andy%2Flinux diff --git a/include/asm-i386/tsc.h b/include/asm-i386/tsc.h index e997891cc7c..a4d806610b7 100644 --- a/include/asm-i386/tsc.h +++ b/include/asm-i386/tsc.h @@ -1 +1,75 @@ -#include +/* + * linux/include/asm-i386/tsc.h + * + * i386 TSC related functions + */ +#ifndef _ASM_i386_TSC_H +#define _ASM_i386_TSC_H + +#include + +/* + * Standard way to access the cycle counter. + */ +typedef unsigned long long cycles_t; + +extern unsigned int cpu_khz; +extern unsigned int tsc_khz; + +static inline cycles_t get_cycles(void) +{ + unsigned long long ret = 0; + +#ifndef CONFIG_X86_TSC + if (!cpu_has_tsc) + return 0; +#endif + +#if defined(CONFIG_X86_GENERIC) || defined(CONFIG_X86_TSC) + rdtscll(ret); +#endif + return ret; +} + +/* Like get_cycles, but make sure the CPU is synchronized. */ +static __always_inline cycles_t get_cycles_sync(void) +{ + unsigned long long ret; + unsigned eax, edx; + + /* + * Use RDTSCP if possible; it is guaranteed to be synchronous + * and doesn't cause a VMEXIT on Hypervisors + */ + alternative_io(ASM_NOP3, ".byte 0x0f,0x01,0xf9", X86_FEATURE_RDTSCP, + ASM_OUTPUT2("=a" (eax), "=d" (edx)), + "a" (0U), "d" (0U) : "ecx", "memory"); + ret = (((unsigned long long)edx) << 32) | ((unsigned long long)eax); + if (ret) + return ret; + + /* + * Don't do an additional sync on CPUs where we know + * RDTSC is already synchronous: + */ + alternative_io("cpuid", ASM_NOP2, X86_FEATURE_SYNC_RDTSC, + "=a" (eax), "0" (1) : "ebx","ecx","edx","memory"); + rdtscll(ret); + + return ret; +} + +extern void tsc_init(void); +extern void mark_tsc_unstable(char *reason); +extern int unsynchronized_tsc(void); +extern void init_tsc_clocksource(void); +int check_tsc_unstable(void); + +/* + * Boot-time check whether the TSCs are synchronized across + * all CPUs/cores: + */ +extern void check_tsc_sync_source(int cpu); +extern void check_tsc_sync_target(void); + +#endif