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git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - arch/x86/include/asm/mwait.h
1 #ifndef _ASM_X86_MWAIT_H
2 #define _ASM_X86_MWAIT_H
4 #include <linux/sched.h>
6 #define MWAIT_SUBSTATE_MASK 0xf
7 #define MWAIT_CSTATE_MASK 0xf
8 #define MWAIT_SUBSTATE_SIZE 4
9 #define MWAIT_HINT2CSTATE(hint) (((hint) >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK)
10 #define MWAIT_HINT2SUBSTATE(hint) ((hint) & MWAIT_CSTATE_MASK)
12 #define CPUID_MWAIT_LEAF 5
13 #define CPUID5_ECX_EXTENSIONS_SUPPORTED 0x1
14 #define CPUID5_ECX_INTERRUPT_BREAK 0x2
16 #define MWAIT_ECX_INTERRUPT_BREAK 0x1
18 static inline void __monitor(const void *eax
, unsigned long ecx
,
21 /* "monitor %eax, %ecx, %edx;" */
22 asm volatile(".byte 0x0f, 0x01, 0xc8;"
23 :: "a" (eax
), "c" (ecx
), "d"(edx
));
26 static inline void __mwait(unsigned long eax
, unsigned long ecx
)
28 /* "mwait %eax, %ecx;" */
29 asm volatile(".byte 0x0f, 0x01, 0xc9;"
30 :: "a" (eax
), "c" (ecx
));
33 static inline void __sti_mwait(unsigned long eax
, unsigned long ecx
)
36 /* "mwait %eax, %ecx;" */
37 asm volatile("sti; .byte 0x0f, 0x01, 0xc9;"
38 :: "a" (eax
), "c" (ecx
));
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).
48 * New with Core Duo processors, MWAIT can take some hints based on CPU
51 static inline void mwait_idle_with_hints(unsigned long eax
, unsigned long ecx
)
53 if (!current_set_polling_and_test()) {
54 if (static_cpu_has_bug(X86_BUG_CLFLUSH_MONITOR
)) {
56 clflush((void *)¤t_thread_info()->flags
);
60 __monitor((void *)¤t_thread_info()->flags
, 0, 0);
64 current_clr_polling();
67 #endif /* _ASM_X86_MWAIT_H */