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1 | #ifndef _ASM_X86_MWAIT_H |
2 | #define _ASM_X86_MWAIT_H | |
3 | ||
16824255 PZ |
4 | #include <linux/sched.h> |
5 | ||
bc83cccc PA |
6 | #define MWAIT_SUBSTATE_MASK 0xf |
7 | #define MWAIT_CSTATE_MASK 0xf | |
8 | #define MWAIT_SUBSTATE_SIZE 4 | |
e022e7eb LB |
9 | #define MWAIT_HINT2CSTATE(hint) (((hint) >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK) |
10 | #define MWAIT_HINT2SUBSTATE(hint) ((hint) & MWAIT_CSTATE_MASK) | |
bc83cccc PA |
11 | |
12 | #define CPUID_MWAIT_LEAF 5 | |
13 | #define CPUID5_ECX_EXTENSIONS_SUPPORTED 0x1 | |
14 | #define CPUID5_ECX_INTERRUPT_BREAK 0x2 | |
15 | ||
16 | #define MWAIT_ECX_INTERRUPT_BREAK 0x1 | |
17 | ||
16824255 PZ |
18 | static inline void __monitor(const void *eax, unsigned long ecx, |
19 | unsigned long edx) | |
20 | { | |
21 | /* "monitor %eax, %ecx, %edx;" */ | |
22 | asm volatile(".byte 0x0f, 0x01, 0xc8;" | |
23 | :: "a" (eax), "c" (ecx), "d"(edx)); | |
24 | } | |
25 | ||
26 | static inline void __mwait(unsigned long eax, unsigned long ecx) | |
27 | { | |
28 | /* "mwait %eax, %ecx;" */ | |
29 | asm volatile(".byte 0x0f, 0x01, 0xc9;" | |
30 | :: "a" (eax), "c" (ecx)); | |
31 | } | |
32 | ||
b253149b LB |
33 | static inline void __sti_mwait(unsigned long eax, unsigned long ecx) |
34 | { | |
35 | trace_hardirqs_on(); | |
36 | /* "mwait %eax, %ecx;" */ | |
37 | asm volatile("sti; .byte 0x0f, 0x01, 0xc9;" | |
38 | :: "a" (eax), "c" (ecx)); | |
39 | } | |
40 | ||
16824255 PZ |
41 | /* |
42 | * This uses new MONITOR/MWAIT instructions on P4 processors with PNI, | |
43 | * which can obviate IPI to trigger checking of need_resched. | |
44 | * We execute MONITOR against need_resched and enter optimized wait state | |
45 | * through MWAIT. Whenever someone changes need_resched, we would be woken | |
46 | * up from MWAIT (without an IPI). | |
47 | * | |
48 | * New with Core Duo processors, MWAIT can take some hints based on CPU | |
49 | * capability. | |
50 | */ | |
51 | static inline void mwait_idle_with_hints(unsigned long eax, unsigned long ecx) | |
52 | { | |
53 | if (!current_set_polling_and_test()) { | |
9b13a93d | 54 | if (static_cpu_has_bug(X86_BUG_CLFLUSH_MONITOR)) { |
7e98b719 | 55 | mb(); |
16824255 | 56 | clflush((void *)¤t_thread_info()->flags); |
7e98b719 PA |
57 | mb(); |
58 | } | |
16824255 PZ |
59 | |
60 | __monitor((void *)¤t_thread_info()->flags, 0, 0); | |
61 | if (!need_resched()) | |
62 | __mwait(eax, ecx); | |
63 | } | |
8cb75e0c | 64 | current_clr_polling(); |
16824255 PZ |
65 | } |
66 | ||
bc83cccc | 67 | #endif /* _ASM_X86_MWAIT_H */ |