xref: /openbmc/linux/arch/x86/include/asm/pvclock.h (revision 63dc02bd)
1 #ifndef _ASM_X86_PVCLOCK_H
2 #define _ASM_X86_PVCLOCK_H
3 
4 #include <linux/clocksource.h>
5 #include <asm/pvclock-abi.h>
6 
7 /* some helper functions for xen and kvm pv clock sources */
8 cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
9 void pvclock_set_flags(u8 flags);
10 unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
11 void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
12 			    struct pvclock_vcpu_time_info *vcpu,
13 			    struct timespec *ts);
14 void pvclock_resume(void);
15 
16 /*
17  * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
18  * yielding a 64-bit result.
19  */
20 static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
21 {
22 	u64 product;
23 #ifdef __i386__
24 	u32 tmp1, tmp2;
25 #else
26 	ulong tmp;
27 #endif
28 
29 	if (shift < 0)
30 		delta >>= -shift;
31 	else
32 		delta <<= shift;
33 
34 #ifdef __i386__
35 	__asm__ (
36 		"mul  %5       ; "
37 		"mov  %4,%%eax ; "
38 		"mov  %%edx,%4 ; "
39 		"mul  %5       ; "
40 		"xor  %5,%5    ; "
41 		"add  %4,%%eax ; "
42 		"adc  %5,%%edx ; "
43 		: "=A" (product), "=r" (tmp1), "=r" (tmp2)
44 		: "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
45 #elif defined(__x86_64__)
46 	__asm__ (
47 		"mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
48 		: [lo]"=a"(product),
49 		  [hi]"=d"(tmp)
50 		: "0"(delta),
51 		  [mul_frac]"rm"((u64)mul_frac));
52 #else
53 #error implement me!
54 #endif
55 
56 	return product;
57 }
58 
59 #endif /* _ASM_X86_PVCLOCK_H */
60