FreeBSD/Linux Kernel Cross Reference
sys/dev/coretemp/coretemp.c

     /*-
      * Copyright (c) 2007, 2008 Rui Paulo <rpaulo@FreeBSD.org>
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
     * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
     * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
     * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     * POSSIBILITY OF SUCH DAMAGE.
     */
    
    /*
     * Device driver for Intel's On Die thermal sensor via MSR.
     * First introduced in Intel's Core line of processors.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/param.h>
    #include <sys/bus.h>
    #include <sys/systm.h>
    #include <sys/types.h>
    #include <sys/module.h>
    #include <sys/conf.h>
    #include <sys/kernel.h>
    #include <sys/sysctl.h>
    #include <sys/proc.h>   /* for curthread */
    #include <sys/sched.h>
    
    #include <machine/specialreg.h>
    #include <machine/cpufunc.h>
    #include <machine/md_var.h>
    
    struct coretemp_softc {
            device_t        sc_dev;
            int             sc_tjmax;
            struct sysctl_oid *sc_oid;
    };
    
    /*
     * Device methods.
     */
    static void     coretemp_identify(driver_t *driver, device_t parent);
    static int      coretemp_probe(device_t dev);
    static int      coretemp_attach(device_t dev);
    static int      coretemp_detach(device_t dev);
    
    static int      coretemp_get_temp(device_t dev);
    static int      coretemp_get_temp_sysctl(SYSCTL_HANDLER_ARGS);
    
    static device_method_t coretemp_methods[] = {
            /* Device interface */
            DEVMETHOD(device_identify,      coretemp_identify),
            DEVMETHOD(device_probe,         coretemp_probe),
            DEVMETHOD(device_attach,        coretemp_attach),
            DEVMETHOD(device_detach,        coretemp_detach),
    
            {0, 0}
    };
    
    static driver_t coretemp_driver = {
            "coretemp",
            coretemp_methods,
            sizeof(struct coretemp_softc),
    };
    
    static devclass_t coretemp_devclass;
    DRIVER_MODULE(coretemp, cpu, coretemp_driver, coretemp_devclass, NULL, NULL);
    
    static void
    coretemp_identify(driver_t *driver, device_t parent)
    {
            device_t child;
            u_int regs[4];
    
            /* Make sure we're not being doubly invoked. */
            if (device_find_child(parent, "coretemp", -1) != NULL)
                    return;
    
            /* Check that CPUID 0x06 is supported and the vendor is Intel.*/
            if (cpu_high < 6 || strcmp(cpu_vendor, "GenuineIntel"))
                    return;
            /*
            * CPUID 0x06 returns 1 if the processor has on-die thermal
            * sensors. EBX[0:3] contains the number of sensors.
            */
           do_cpuid(0x06, regs);
           if ((regs[0] & 0x1) != 1)
                   return;
   
           /*
            * We add a child for each CPU since settings must be performed
            * on each CPU in the SMP case.
            */
           child = device_add_child(parent, "coretemp", -1);
           if (child == NULL)
                   device_printf(parent, "add coretemp child failed\n");
   }
   
   static int
   coretemp_probe(device_t dev)
   {
           if (resource_disabled("coretemp", 0))
                   return (ENXIO);
   
           device_set_desc(dev, "CPU On-Die Thermal Sensors");
   
           return (BUS_PROBE_GENERIC);
   }
   
   static int
   coretemp_attach(device_t dev)
   {
           struct coretemp_softc *sc = device_get_softc(dev);
           device_t pdev;
           uint64_t msr;
           int cpu_model;
           int cpu_mask;
   
           sc->sc_dev = dev;
           pdev = device_get_parent(dev);
           cpu_model = (cpu_id >> 4) & 15;
           /* extended model */
           cpu_model += ((cpu_id >> 16) & 0xf) << 4;
           cpu_mask = cpu_id & 15;
   
           /*
            * Some CPUs, namely the PIII, don't have thermal sensors, but
            * report them when the CPUID check is performed in
            * coretemp_identify(). This leads to a later GPF when the sensor
            * is queried via a MSR, so we stop here.
            */
           if (cpu_model < 0xe)
                   return (ENXIO);
               
           /*
            * Check for errata AE18.
            * "Processor Digital Thermal Sensor (DTS) Readout stops
            *  updating upon returning from C3/C4 state."
            *
            * Adapted from the Linux coretemp driver.
            */
           if (cpu_model == 0xe && cpu_mask < 0xc) {
                   msr = rdmsr(MSR_BIOS_SIGN);
                   msr = msr >> 32;
                   if (msr < 0x39) {
                           device_printf(dev, "not supported (Intel errata "
                               "AE18), try updating your BIOS\n");
                           return (ENXIO);
                   }
           }
           /*
            * On some Core 2 CPUs, there's an undocumented MSR that
            * can tell us if Tj(max) is 100 or 85.
            *
            * The if-clause for CPUs having the MSR_IA32_EXT_CONFIG was adapted
            * from the Linux coretemp driver.
            */
           sc->sc_tjmax = 100;
           if ((cpu_model == 0xf && cpu_mask >= 2) || cpu_model == 0xe) {
                   msr = rdmsr(MSR_IA32_EXT_CONFIG);
                   if (msr & (1 << 30))
                           sc->sc_tjmax = 85;
           }
   
           /*
            * Add the "temperature" MIB to dev.cpu.N.
            */
           sc->sc_oid = SYSCTL_ADD_PROC(device_get_sysctl_ctx(pdev),
               SYSCTL_CHILDREN(device_get_sysctl_tree(pdev)),
               OID_AUTO, "temperature",
               CTLTYPE_INT | CTLFLAG_RD,
               dev, 0, coretemp_get_temp_sysctl, "I",
               "Current temperature in degC");
   
           return (0);
   }
   
   static int
   coretemp_detach(device_t dev)
   {
           struct coretemp_softc *sc = device_get_softc(dev);
   
           sysctl_remove_oid(sc->sc_oid, 1, 0);
   
           return (0);
   }
   
   
   static int
   coretemp_get_temp(device_t dev)
   {
           uint64_t msr;
           int temp;
           int cpu = device_get_unit(dev);
           struct coretemp_softc *sc = device_get_softc(dev);
           char stemp[16];
   
           mtx_lock_spin(&sched_lock);
           sched_bind(curthread, cpu);
           mtx_unlock_spin(&sched_lock);
   
           /*
            * The digital temperature reading is located at bit 16
            * of MSR_THERM_STATUS.
            *
            * There is a bit on that MSR that indicates whether the
            * temperature is valid or not.
            *
            * The temperature is computed by subtracting the temperature
            * reading by Tj(max).
            */
           msr = rdmsr(MSR_THERM_STATUS);
   
           mtx_lock_spin(&sched_lock);
           sched_unbind(curthread);
           mtx_unlock_spin(&sched_lock);
   
           /*
            * Check for Thermal Status and Thermal Status Log.
            */
           if ((msr & 0x3) == 0x3)
                   device_printf(dev, "PROCHOT asserted\n");
   
           /*
            * Bit 31 contains "Reading valid"
            */
           if (((msr >> 31) & 0x1) == 1) {
                   /*
                    * Starting on bit 16 and ending on bit 22.
                    */
                   temp = sc->sc_tjmax - ((msr >> 16) & 0x7f);
           } else
                   temp = -1;
   
           /*
            * Check for Critical Temperature Status and Critical
            * Temperature Log.
            * It doesn't really matter if the current temperature is
            * invalid because the "Critical Temperature Log" bit will
            * tell us if the Critical Temperature has been reached in
            * past. It's not directly related to the current temperature.
            *
            * If we reach a critical level, allow devctl(4) to catch this
            * and shutdown the system.
            */
           if (((msr >> 4) & 0x3) == 0x3) {
                   device_printf(dev, "critical temperature detected, "
                       "suggest system shutdown\n");
                   snprintf(stemp, sizeof(stemp), "%d", temp);
                   devctl_notify("coretemp", "Thermal", stemp, "notify=0xcc");
           }
   
           return (temp);
   }
   
   static int
   coretemp_get_temp_sysctl(SYSCTL_HANDLER_ARGS)
   {
           device_t dev = (device_t) arg1;
           int temp;
   
           temp = coretemp_get_temp(dev);
   
           return (sysctl_handle_int(oidp, &temp, 0, req));
   }

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