diff options
Diffstat (limited to 'arch/x86/include/asm/mwait.h')
| -rw-r--r-- | arch/x86/include/asm/mwait.h | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/arch/x86/include/asm/mwait.h b/arch/x86/include/asm/mwait.h index a43b35b35049..73d997aa2966 100644 --- a/arch/x86/include/asm/mwait.h +++ b/arch/x86/include/asm/mwait.h @@ -22,6 +22,8 @@ #define MWAITX_ECX_TIMER_ENABLE BIT(1) #define MWAITX_MAX_WAIT_CYCLES UINT_MAX #define MWAITX_DISABLE_CSTATES 0xf0 +#define TPAUSE_C01_STATE 1 +#define TPAUSE_C02_STATE 0 u32 get_umwait_control_msr(void); @@ -122,4 +124,24 @@ static inline void mwait_idle_with_hints(unsigned long eax, unsigned long ecx) current_clr_polling(); } +/* + * Caller can specify whether to enter C0.1 (low latency, less + * power saving) or C0.2 state (saves more power, but longer wakeup + * latency). This may be overridden by the IA32_UMWAIT_CONTROL MSR + * which can force requests for C0.2 to be downgraded to C0.1. + */ +static inline void __tpause(u32 ecx, u32 edx, u32 eax) +{ + /* "tpause %ecx, %edx, %eax;" */ + #ifdef CONFIG_AS_TPAUSE + asm volatile("tpause %%ecx\n" + : + : "c"(ecx), "d"(edx), "a"(eax)); + #else + asm volatile(".byte 0x66, 0x0f, 0xae, 0xf1\t\n" + : + : "c"(ecx), "d"(edx), "a"(eax)); + #endif +} + #endif /* _ASM_X86_MWAIT_H */ |