summaryrefslogtreecommitdiff
path: root/arch/x86/include/asm/mwait.h
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/include/asm/mwait.h')
-rw-r--r--arch/x86/include/asm/mwait.h24
1 files changed, 23 insertions, 1 deletions
diff --git a/arch/x86/include/asm/mwait.h b/arch/x86/include/asm/mwait.h
index b809f117f3f4..73d997aa2966 100644
--- a/arch/x86/include/asm/mwait.h
+++ b/arch/x86/include/asm/mwait.h
@@ -20,8 +20,10 @@
#define MWAIT_ECX_INTERRUPT_BREAK 0x1
#define MWAITX_ECX_TIMER_ENABLE BIT(1)
-#define MWAITX_MAX_LOOPS ((u32)-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 */