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