2 * Copyright (c) 2007, 2008 Rui Paulo <rpaulo@FreeBSD.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
16 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
17 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
18 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
19 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
20 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
22 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
23 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
24 * POSSIBILITY OF SUCH DAMAGE.
28 * Device driver for Intel's On Die thermal sensor via MSR.
29 * First introduced in Intel's Core line of processors.
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
35 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/types.h>
39 #include <sys/module.h>
41 #include <sys/kernel.h>
42 #include <sys/sysctl.h>
43 #include <sys/proc.h> /* for curthread */
44 #include <sys/sched.h>
46 #include <machine/specialreg.h>
47 #include <machine/cpufunc.h>
48 #include <machine/md_var.h>
50 struct coretemp_softc {
53 struct sysctl_oid *sc_oid;
59 static void coretemp_identify(driver_t *driver, device_t parent);
60 static int coretemp_probe(device_t dev);
61 static int coretemp_attach(device_t dev);
62 static int coretemp_detach(device_t dev);
64 static int coretemp_get_temp(device_t dev);
65 static int coretemp_get_temp_sysctl(SYSCTL_HANDLER_ARGS);
67 static device_method_t coretemp_methods[] = {
68 /* Device interface */
69 DEVMETHOD(device_identify, coretemp_identify),
70 DEVMETHOD(device_probe, coretemp_probe),
71 DEVMETHOD(device_attach, coretemp_attach),
72 DEVMETHOD(device_detach, coretemp_detach),
77 static driver_t coretemp_driver = {
80 sizeof(struct coretemp_softc),
83 static devclass_t coretemp_devclass;
84 DRIVER_MODULE(coretemp, cpu, coretemp_driver, coretemp_devclass, NULL, NULL);
87 coretemp_identify(driver_t *driver, device_t parent)
92 /* Make sure we're not being doubly invoked. */
93 if (device_find_child(parent, "coretemp", -1) != NULL)
96 /* Check that CPUID 0x06 is supported and the vendor is Intel.*/
97 if (cpu_high < 6 || strcmp(cpu_vendor, "GenuineIntel"))
100 * CPUID 0x06 returns 1 if the processor has on-die thermal
101 * sensors. EBX[0:3] contains the number of sensors.
103 do_cpuid(0x06, regs);
104 if ((regs[0] & 0x1) != 1)
108 * We add a child for each CPU since settings must be performed
109 * on each CPU in the SMP case.
111 child = device_add_child(parent, "coretemp", -1);
113 device_printf(parent, "add coretemp child failed\n");
117 coretemp_probe(device_t dev)
119 if (resource_disabled("coretemp", 0))
122 device_set_desc(dev, "CPU On-Die Thermal Sensors");
124 return (BUS_PROBE_GENERIC);
128 coretemp_attach(device_t dev)
130 struct coretemp_softc *sc = device_get_softc(dev);
137 pdev = device_get_parent(dev);
138 cpu_model = (cpu_id >> 4) & 15;
140 cpu_model += ((cpu_id >> 16) & 0xf) << 4;
141 cpu_mask = cpu_id & 15;
144 * Some CPUs, namely the PIII, don't have thermal sensors, but
145 * report them when the CPUID check is performed in
146 * coretemp_identify(). This leads to a later GPF when the sensor
147 * is queried via a MSR, so we stop here.
153 * XXXrpaulo: I have this CPU model and when it returns from C3
154 * coretemp continues to function properly.
158 * Check for errata AE18.
159 * "Processor Digital Thermal Sensor (DTS) Readout stops
160 * updating upon returning from C3/C4 state."
162 * Adapted from the Linux coretemp driver.
164 if (cpu_model == 0xe && cpu_mask < 0xc) {
165 msr = rdmsr(MSR_BIOS_SIGN);
168 device_printf(dev, "not supported (Intel errata "
169 "AE18), try updating your BIOS\n");
175 * On some Core 2 CPUs, there's an undocumented MSR that
176 * can tell us if Tj(max) is 100 or 85.
178 * The if-clause for CPUs having the MSR_IA32_EXT_CONFIG was adapted
179 * from the Linux coretemp driver.
182 if ((cpu_model == 0xf && cpu_mask >= 2) || cpu_model == 0xe) {
183 msr = rdmsr(MSR_IA32_EXT_CONFIG);
189 * Add the "temperature" MIB to dev.cpu.N.
191 sc->sc_oid = SYSCTL_ADD_PROC(device_get_sysctl_ctx(pdev),
192 SYSCTL_CHILDREN(device_get_sysctl_tree(pdev)),
193 OID_AUTO, "temperature",
194 CTLTYPE_INT | CTLFLAG_RD,
195 dev, 0, coretemp_get_temp_sysctl, "I",
196 "Current temperature in degC");
202 coretemp_detach(device_t dev)
204 struct coretemp_softc *sc = device_get_softc(dev);
206 sysctl_remove_oid(sc->sc_oid, 1, 0);
213 coretemp_get_temp(device_t dev)
217 int cpu = device_get_unit(dev);
218 struct coretemp_softc *sc = device_get_softc(dev);
221 thread_lock(curthread);
222 sched_bind(curthread, cpu);
223 thread_unlock(curthread);
226 * The digital temperature reading is located at bit 16
227 * of MSR_THERM_STATUS.
229 * There is a bit on that MSR that indicates whether the
230 * temperature is valid or not.
232 * The temperature is computed by subtracting the temperature
233 * reading by Tj(max).
235 msr = rdmsr(MSR_THERM_STATUS);
237 thread_lock(curthread);
238 sched_unbind(curthread);
239 thread_unlock(curthread);
242 * Check for Thermal Status and Thermal Status Log.
244 if ((msr & 0x3) == 0x3)
245 device_printf(dev, "PROCHOT asserted\n");
248 * Bit 31 contains "Reading valid"
250 if (((msr >> 31) & 0x1) == 1) {
252 * Starting on bit 16 and ending on bit 22.
254 temp = sc->sc_tjmax - ((msr >> 16) & 0x7f);
259 * Check for Critical Temperature Status and Critical
261 * It doesn't really matter if the current temperature is
262 * invalid because the "Critical Temperature Log" bit will
263 * tell us if the Critical Temperature has been reached in
264 * past. It's not directly related to the current temperature.
266 * If we reach a critical level, allow devctl(4) to catch this
267 * and shutdown the system.
269 if (((msr >> 4) & 0x3) == 0x3) {
270 device_printf(dev, "critical temperature detected, "
271 "suggest system shutdown\n");
272 snprintf(stemp, sizeof(stemp), "%d", temp);
273 devctl_notify("coretemp", "Thermal", stemp, "notify=0xcc");
280 coretemp_get_temp_sysctl(SYSCTL_HANDLER_ARGS)
282 device_t dev = (device_t) arg1;
285 temp = coretemp_get_temp(dev);
287 return (sysctl_handle_int(oidp, &temp, 0, req));