| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 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 timespec64 *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 */ |