1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_X86_PVCLOCK_H 3 #define _ASM_X86_PVCLOCK_H 4 5 #include <asm/clocksource.h> 6 #include <asm/pvclock-abi.h> 7 8 struct timespec64; 9 /* some helper functions for xen and kvm pv clock sources */ 10 u64 pvclock_clocksource_read(struct pvclock_vcpu_time_info *src); 11 u64 pvclock_clocksource_read_nowd(struct pvclock_vcpu_time_info *src); 12 u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src); 13 void pvclock_set_flags(u8 flags); 14 unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src); 15 void pvclock_read_wallclock(struct pvclock_wall_clock *wall, 16 struct pvclock_vcpu_time_info *vcpu, 17 struct timespec64 *ts); 18 void pvclock_resume(void); 19 20 void pvclock_touch_watchdogs(void); 21 22 static __always_inline 23 unsigned pvclock_read_begin(const struct pvclock_vcpu_time_info *src) 24 { 25 unsigned version = src->version & ~1; 26 /* Make sure that the version is read before the data. */ 27 virt_rmb(); 28 return version; 29 } 30 31 static __always_inline 32 bool pvclock_read_retry(const struct pvclock_vcpu_time_info *src, 33 unsigned version) 34 { 35 /* Make sure that the version is re-read after the data. */ 36 virt_rmb(); 37 return unlikely(version != src->version); 38 } 39 40 /* 41 * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction, 42 * yielding a 64-bit result. 43 */ 44 static __always_inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift) 45 { 46 u64 product; 47 #ifdef __i386__ 48 u32 tmp1, tmp2; 49 #else 50 ulong tmp; 51 #endif 52 53 if (shift < 0) 54 delta >>= -shift; 55 else 56 delta <<= shift; 57 58 #ifdef __i386__ 59 __asm__ ( 60 "mul %5 ; " 61 "mov %4,%%eax ; " 62 "mov %%edx,%4 ; " 63 "mul %5 ; " 64 "xor %5,%5 ; " 65 "add %4,%%eax ; " 66 "adc %5,%%edx ; " 67 : "=A" (product), "=r" (tmp1), "=r" (tmp2) 68 : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) ); 69 #elif defined(__x86_64__) 70 __asm__ ( 71 "mulq %[mul_frac] ; shrd $32, %[hi], %[lo]" 72 : [lo]"=a"(product), 73 [hi]"=d"(tmp) 74 : "0"(delta), 75 [mul_frac]"rm"((u64)mul_frac)); 76 #else 77 #error implement me! 78 #endif 79 80 return product; 81 } 82 83 static __always_inline 84 u64 __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src, u64 tsc) 85 { 86 u64 delta = tsc - src->tsc_timestamp; 87 u64 offset = pvclock_scale_delta(delta, src->tsc_to_system_mul, 88 src->tsc_shift); 89 return src->system_time + offset; 90 } 91 92 struct pvclock_vsyscall_time_info { 93 struct pvclock_vcpu_time_info pvti; 94 } __attribute__((__aligned__(SMP_CACHE_BYTES))); 95 96 #define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info) 97 98 #ifdef CONFIG_PARAVIRT_CLOCK 99 void pvclock_set_pvti_cpu0_va(struct pvclock_vsyscall_time_info *pvti); 100 struct pvclock_vsyscall_time_info *pvclock_get_pvti_cpu0_va(void); 101 #else 102 static inline struct pvclock_vsyscall_time_info *pvclock_get_pvti_cpu0_va(void) 103 { 104 return NULL; 105 } 106 #endif 107 108 #endif /* _ASM_X86_PVCLOCK_H */ 109