xref: /illumos-gate/usr/src/uts/i86xpv/io/xpvtod.c (revision 86d949f9497332fe19be6b5d711d265eb957439f)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #include <sys/types.h>
28 #include <sys/systm.h>
29 #include <sys/mutex.h>
30 #include <sys/time.h>
31 #include <sys/clock.h>
32 #include <sys/archsystm.h>
33 #include <sys/modctl.h>
34 #include <sys/autoconf.h>
35 #include <sys/cmn_err.h>
36 #include <sys/atomic.h>
37 #include <sys/hypervisor.h>
38 
39 /*
40  * tod driver module for i86xpv
41  */
42 
43 static timestruc_t
44 todxen_get(tod_ops_t *top)
45 {
46 	todinfo_t tod;
47 	timestruc_t ts, wcts;
48 	shared_info_t *si = HYPERVISOR_shared_info;
49 	uint32_t xen_wc_version;
50 	hrtime_t now;
51 
52 	ASSERT(MUTEX_HELD(&tod_lock));
53 
54 	/*
55 	 * Pick up the wallclock base time
56 	 */
57 	do {
58 		xen_wc_version = si->wc_version;
59 
60 		membar_consumer();
61 
62 		wcts.tv_sec = si->wc_sec;
63 		wcts.tv_nsec = si->wc_nsec;
64 
65 		membar_consumer();
66 
67 	} while ((si->wc_version & 1) | (xen_wc_version ^ si->wc_version));
68 
69 	/*
70 	 * Compute the TOD as the wallclock (boot) time plus time-since-boot
71 	 * (/not/ hrtime!) and normalize.
72 	 */
73 	now = xpv_getsystime() +
74 	    (hrtime_t)wcts.tv_nsec + (hrtime_t)wcts.tv_sec * NANOSEC;
75 	ts.tv_sec = (time_t)(now / NANOSEC);
76 	ts.tv_nsec = (long)(now % NANOSEC);
77 
78 	/*
79 	 * Apply GMT lag correction from /etc/rtc_config to get UTC time
80 	 */
81 	ts.tv_sec += ggmtl();
82 
83 	/*
84 	 * Validate the TOD in case of total insanity
85 	 */
86 	tod = utc_to_tod(ts.tv_sec);
87 	if (tod.tod_year < 69) {
88 		static int range_warn = 1;	/* warn only once */
89 
90 		if (range_warn) {
91 			/*
92 			 * If we're dom0, go invoke the underlying driver; the
93 			 * routine should complain if it discovers something
94 			 * wrong.
95 			 */
96 			if (DOMAIN_IS_INITDOMAIN(xen_info))
97 				(void) TODOP_GET(top->tod_next);
98 
99 			/*
100 			 * Check the virtual hardware.
101 			 */
102 			if (tod.tod_year > 38)
103 				cmn_err(CE_WARN,
104 				    "hypervisor wall clock is out "
105 				    "of range -- time needs to be reset");
106 			range_warn = 0;
107 		}
108 		tod.tod_year += 100;
109 		ts.tv_sec = tod_to_utc(tod);
110 	}
111 
112 	return (ts);
113 }
114 
115 /*
116  * On dom0, invoke the underlying driver to update the physical RTC,
117  * and tell the hypervisor to update its idea of global time.
118  *
119  * On domU, we don't have permission to update the machine's physical RTC,
120  * so quietly ignore the attempt.
121  */
122 static void
123 todxen_set(tod_ops_t *top, timestruc_t ts)
124 {
125 	xen_platform_op_t op;
126 
127 	if (DOMAIN_IS_INITDOMAIN(xen_info)) {
128 		ASSERT(MUTEX_HELD(&tod_lock));
129 		TODOP_SET(top->tod_next, ts);
130 
131 		op.cmd = XENPF_settime;
132 		op.interface_version = XENPF_INTERFACE_VERSION;
133 		op.u.settime.secs = ts.tv_sec - ggmtl();
134 		op.u.settime.nsecs = ts.tv_nsec;
135 		op.u.settime.system_time = xpv_getsystime();
136 		(void) HYPERVISOR_platform_op(&op);
137 	}
138 }
139 
140 static tod_ops_t todxen_ops = {
141 	TOD_OPS_VERSION,
142 	todxen_get,
143 	todxen_set,
144 	NULL
145 };
146 
147 static struct modlmisc modlmisc = {
148 	&mod_miscops,
149 	"TOD module for i86xpv"
150 };
151 
152 static struct modlinkage modl = {
153 	MODREV_1,
154 	&modlmisc
155 };
156 
157 int
158 _init(void)
159 {
160 	/*
161 	 * In future we might need to do something more sophisticated
162 	 * for versioning, i.e. dealing with older hardware TOD modules
163 	 * underneath us, but for now, anything else but "same" is a
164 	 * fatal error.
165 	 */
166 	if (tod_ops->tod_version != todxen_ops.tod_version)
167 		panic("TOD module version mismatch");
168 
169 	/*
170 	 * Stitch the ops vector linkage together, with this module
171 	 * sitting on the "front" of the ops list.
172 	 */
173 	todxen_ops.tod_next = tod_ops;
174 	tod_ops = &todxen_ops;
175 
176 	return (mod_install(&modl));
177 }
178 
179 int
180 _fini(void)
181 {
182 	return (EBUSY);
183 }
184 
185 int
186 _info(struct modinfo *modinfo)
187 {
188 	return (mod_info(&modl, modinfo));
189 }
190