1*50006539SOliver Upton /* SPDX-License-Identifier: GPL-2.0 */
2*50006539SOliver Upton #ifndef _ASM_X86_PVCLOCK_H
3*50006539SOliver Upton #define _ASM_X86_PVCLOCK_H
4*50006539SOliver Upton
5*50006539SOliver Upton #include <asm/barrier.h>
6*50006539SOliver Upton #include <asm/pvclock-abi.h>
7*50006539SOliver Upton
8*50006539SOliver Upton /* some helper functions for xen and kvm pv clock sources */
9*50006539SOliver Upton u64 pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
10*50006539SOliver Upton u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src);
11*50006539SOliver Upton void pvclock_set_flags(u8 flags);
12*50006539SOliver Upton unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
13*50006539SOliver Upton void pvclock_resume(void);
14*50006539SOliver Upton
15*50006539SOliver Upton void pvclock_touch_watchdogs(void);
16*50006539SOliver Upton
17*50006539SOliver Upton static __always_inline
pvclock_read_begin(const struct pvclock_vcpu_time_info * src)18*50006539SOliver Upton unsigned pvclock_read_begin(const struct pvclock_vcpu_time_info *src)
19*50006539SOliver Upton {
20*50006539SOliver Upton unsigned version = src->version & ~1;
21*50006539SOliver Upton /* Make sure that the version is read before the data. */
22*50006539SOliver Upton rmb();
23*50006539SOliver Upton return version;
24*50006539SOliver Upton }
25*50006539SOliver Upton
26*50006539SOliver Upton static __always_inline
pvclock_read_retry(const struct pvclock_vcpu_time_info * src,unsigned version)27*50006539SOliver Upton bool pvclock_read_retry(const struct pvclock_vcpu_time_info *src,
28*50006539SOliver Upton unsigned version)
29*50006539SOliver Upton {
30*50006539SOliver Upton /* Make sure that the version is re-read after the data. */
31*50006539SOliver Upton rmb();
32*50006539SOliver Upton return version != src->version;
33*50006539SOliver Upton }
34*50006539SOliver Upton
35*50006539SOliver Upton /*
36*50006539SOliver Upton * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
37*50006539SOliver Upton * yielding a 64-bit result.
38*50006539SOliver Upton */
pvclock_scale_delta(u64 delta,u32 mul_frac,int shift)39*50006539SOliver Upton static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
40*50006539SOliver Upton {
41*50006539SOliver Upton u64 product;
42*50006539SOliver Upton #ifdef __i386__
43*50006539SOliver Upton u32 tmp1, tmp2;
44*50006539SOliver Upton #else
45*50006539SOliver Upton unsigned long tmp;
46*50006539SOliver Upton #endif
47*50006539SOliver Upton
48*50006539SOliver Upton if (shift < 0)
49*50006539SOliver Upton delta >>= -shift;
50*50006539SOliver Upton else
51*50006539SOliver Upton delta <<= shift;
52*50006539SOliver Upton
53*50006539SOliver Upton #ifdef __i386__
54*50006539SOliver Upton __asm__ (
55*50006539SOliver Upton "mul %5 ; "
56*50006539SOliver Upton "mov %4,%%eax ; "
57*50006539SOliver Upton "mov %%edx,%4 ; "
58*50006539SOliver Upton "mul %5 ; "
59*50006539SOliver Upton "xor %5,%5 ; "
60*50006539SOliver Upton "add %4,%%eax ; "
61*50006539SOliver Upton "adc %5,%%edx ; "
62*50006539SOliver Upton : "=A" (product), "=r" (tmp1), "=r" (tmp2)
63*50006539SOliver Upton : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
64*50006539SOliver Upton #elif defined(__x86_64__)
65*50006539SOliver Upton __asm__ (
66*50006539SOliver Upton "mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
67*50006539SOliver Upton : [lo]"=a"(product),
68*50006539SOliver Upton [hi]"=d"(tmp)
69*50006539SOliver Upton : "0"(delta),
70*50006539SOliver Upton [mul_frac]"rm"((u64)mul_frac));
71*50006539SOliver Upton #else
72*50006539SOliver Upton #error implement me!
73*50006539SOliver Upton #endif
74*50006539SOliver Upton
75*50006539SOliver Upton return product;
76*50006539SOliver Upton }
77*50006539SOliver Upton
78*50006539SOliver Upton static __always_inline
__pvclock_read_cycles(const struct pvclock_vcpu_time_info * src,u64 tsc)79*50006539SOliver Upton u64 __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src, u64 tsc)
80*50006539SOliver Upton {
81*50006539SOliver Upton u64 delta = tsc - src->tsc_timestamp;
82*50006539SOliver Upton u64 offset = pvclock_scale_delta(delta, src->tsc_to_system_mul,
83*50006539SOliver Upton src->tsc_shift);
84*50006539SOliver Upton return src->system_time + offset;
85*50006539SOliver Upton }
86*50006539SOliver Upton
87*50006539SOliver Upton struct pvclock_vsyscall_time_info {
88*50006539SOliver Upton struct pvclock_vcpu_time_info pvti;
89*50006539SOliver Upton } __attribute__((__aligned__(64)));
90*50006539SOliver Upton
91*50006539SOliver Upton #define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info)
92*50006539SOliver Upton
93*50006539SOliver Upton #ifdef CONFIG_PARAVIRT_CLOCK
94*50006539SOliver Upton void pvclock_set_pvti_cpu0_va(struct pvclock_vsyscall_time_info *pvti);
95*50006539SOliver Upton struct pvclock_vsyscall_time_info *pvclock_get_pvti_cpu0_va(void);
96*50006539SOliver Upton #else
pvclock_get_pvti_cpu0_va(void)97*50006539SOliver Upton static inline struct pvclock_vsyscall_time_info *pvclock_get_pvti_cpu0_va(void)
98*50006539SOliver Upton {
99*50006539SOliver Upton return NULL;
100*50006539SOliver Upton }
101*50006539SOliver Upton #endif
102*50006539SOliver Upton
103*50006539SOliver Upton #endif /* _ASM_X86_PVCLOCK_H */
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