1/*-
  2 * Copyright (c) 2014, Bryan Venteicher <bryanv@FreeBSD.org>
  3 * All rights reserved.
  4 *
  5 * Redistribution and use in source and binary forms, with or without
  6 * modification, are permitted provided that the following conditions
  7 * are met:
  8 * 1. Redistributions of source code must retain the above copyright
  9 *    notice, this list of conditions and the following disclaimer.
 10 * 2. Redistributions in binary form must reproduce the above copyright
 11 *    notice, this list of conditions and the following disclaimer in the
 12 *    documentation and/or other materials provided with the distribution.
 13 *
 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 24 * SUCH DAMAGE.
 25 */
 26
 27#ifndef X86_PVCLOCK
 28#define X86_PVCLOCK
 29
 30#include <sys/types.h>
 31
 32#ifdef _KERNEL
 33#include <sys/timetc.h>
 34#endif /* _KERNEL */
 35
 36#define	PVCLOCK_CDEVNAME		"pvclock"
 37
 38struct pvclock_vcpu_time_info {
 39	uint32_t	version;
 40	uint32_t	pad0;
 41	uint64_t	tsc_timestamp;
 42	uint64_t	system_time;
 43	uint32_t	tsc_to_system_mul;
 44	int8_t		tsc_shift;
 45	uint8_t		flags;
 46	uint8_t		pad[2];
 47};
 48
 49#define PVCLOCK_FLAG_TSC_STABLE		0x01
 50#define PVCLOCK_FLAG_GUEST_PASUED	0x02
 51
 52/*
 53 * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
 54 * yielding a 64-bit result.
 55 */
 56static inline uint64_t
 57pvclock_scale_delta(uint64_t delta, uint32_t mul_frac, int shift)
 58{
 59	uint64_t product;
 60
 61	if (shift < 0)
 62		delta >>= -shift;
 63	else
 64		delta <<= shift;
 65#if defined(__i386__)
 66	{
 67		uint32_t tmp1, tmp2;
 68
 69		/**
 70		 * For i386, the formula looks like:
 71		 *
 72		 *   lower = (mul_frac * (delta & UINT_MAX)) >> 32
 73		 *   upper = mul_frac * (delta >> 32)
 74		 *   product = lower + upper
 75		 */
 76		__asm__ (
 77			"mul  %5       ; "
 78			"mov  %4,%%eax ; "
 79			"mov  %%edx,%4 ; "
 80			"mul  %5       ; "
 81			"xor  %5,%5    ; "
 82			"add  %4,%%eax ; "
 83			"adc  %5,%%edx ; "
 84			: "=A" (product), "=r" (tmp1), "=r" (tmp2)
 85			: "a" ((uint32_t)delta), "1" ((uint32_t)(delta >> 32)),
 86			  "2" (mul_frac) );
 87	}
 88#elif defined(__amd64__)
 89	{
 90		unsigned long tmp;
 91
 92		__asm__ (
 93			"mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
 94			: [lo]"=a" (product), [hi]"=d" (tmp)
 95			: "0" (delta), [mul_frac]"rm"((uint64_t)mul_frac));
 96	}
 97#else
 98#error "pvclock: unsupported x86 architecture?"
 99#endif
100	return (product);
101}
102
103#ifdef _KERNEL
104
105typedef struct pvclock_wall_clock *pvclock_get_wallclock_t(void *arg);
106
107struct pvclock_wall_clock {
108	uint32_t	version;
109	uint32_t	sec;
110	uint32_t	nsec;
111};
112
113struct pvclock {
114	/* Public; initialized by the caller of 'pvclock_init()': */
115	pvclock_get_wallclock_t		*get_wallclock;
116	void				*get_wallclock_arg;
117	struct pvclock_vcpu_time_info	*timeinfos;
118	bool				 stable_flag_supported;
119
120	/* Private; initialized by the 'pvclock' API: */
121	bool				 vdso_force_unstable;
122	bool				 vdso_enable_without_rdtscp;
123	struct timecounter		 tc;
124	struct cdev			*cdev;
125};
126
127/*
128 * NOTE: 'pvclock_get_timecount()' and 'pvclock_get_wallclock()' are purely
129 * transitional; they should be removed after 'dev/xen/timer/timer.c' has been
130 * migrated to the 'struct pvclock' API.
131 */
132void		pvclock_resume(void);
133uint64_t	pvclock_tsc_freq(struct pvclock_vcpu_time_info *ti);
134uint64_t	pvclock_get_timecount(struct pvclock_vcpu_time_info *ti);
135void		pvclock_get_wallclock(struct pvclock_wall_clock *wc,
136		    struct timespec *ts);
137
138void		pvclock_init(struct pvclock *pvc, device_t dev,
139		    const char *tc_name, int tc_quality, u_int tc_flags);
140void		pvclock_gettime(struct pvclock *pvc, struct timespec *ts);
141int		pvclock_destroy(struct pvclock *pvc);
142
143#endif /* _KERNEL */
144
145#endif