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 u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src); 10 void pvclock_set_flags(u8 flags); 11 unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src); 12 void pvclock_read_wallclock(struct pvclock_wall_clock *wall, 13 struct pvclock_vcpu_time_info *vcpu, 14 struct timespec *ts); 15 void pvclock_resume(void); 16 17 /* 18 * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction, 19 * yielding a 64-bit result. 20 */ 21 static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift) 22 { 23 u64 product; 24 #ifdef __i386__ 25 u32 tmp1, tmp2; 26 #else 27 ulong tmp; 28 #endif 29 30 if (shift < 0) 31 delta >>= -shift; 32 else 33 delta <<= shift; 34 35 #ifdef __i386__ 36 __asm__ ( 37 "mul %5 ; " 38 "mov %4,%%eax ; " 39 "mov %%edx,%4 ; " 40 "mul %5 ; " 41 "xor %5,%5 ; " 42 "add %4,%%eax ; " 43 "adc %5,%%edx ; " 44 : "=A" (product), "=r" (tmp1), "=r" (tmp2) 45 : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) ); 46 #elif defined(__x86_64__) 47 __asm__ ( 48 "mulq %[mul_frac] ; shrd $32, %[hi], %[lo]" 49 : [lo]"=a"(product), 50 [hi]"=d"(tmp) 51 : "0"(delta), 52 [mul_frac]"rm"((u64)mul_frac)); 53 #else 54 #error implement me! 55 #endif 56 57 return product; 58 } 59 60 static __always_inline 61 u64 pvclock_get_nsec_offset(const struct pvclock_vcpu_time_info *src) 62 { 63 u64 delta = __native_read_tsc() - src->tsc_timestamp; 64 return pvclock_scale_delta(delta, src->tsc_to_system_mul, 65 src->tsc_shift); 66 } 67 68 static __always_inline 69 unsigned __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src, 70 cycle_t *cycles, u8 *flags) 71 { 72 unsigned version; 73 cycle_t ret, offset; 74 u8 ret_flags; 75 76 version = src->version; 77 /* Note: emulated platforms which do not advertise SSE2 support 78 * result in kvmclock not using the necessary RDTSC barriers. 79 * Without barriers, it is possible that RDTSC instruction reads from 80 * the time stamp counter outside rdtsc_barrier protected section 81 * below, resulting in violation of monotonicity. 82 */ 83 rdtsc_barrier(); 84 offset = pvclock_get_nsec_offset(src); 85 ret = src->system_time + offset; 86 ret_flags = src->flags; 87 rdtsc_barrier(); 88 89 *cycles = ret; 90 *flags = ret_flags; 91 return version; 92 } 93 94 struct pvclock_vsyscall_time_info { 95 struct pvclock_vcpu_time_info pvti; 96 } __attribute__((__aligned__(SMP_CACHE_BYTES))); 97 98 #define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info) 99 #define PVCLOCK_VSYSCALL_NR_PAGES (((NR_CPUS-1)/(PAGE_SIZE/PVTI_SIZE))+1) 100 101 int __init pvclock_init_vsyscall(struct pvclock_vsyscall_time_info *i, 102 int size); 103 struct pvclock_vcpu_time_info *pvclock_get_vsyscall_time_info(int cpu); 104 105 #endif /* _ASM_X86_PVCLOCK_H */ 106