The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/i386/i386/perfmon.c

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    1 /*-
    2  * Copyright 1996 Massachusetts Institute of Technology
    3  *
    4  * Permission to use, copy, modify, and distribute this software and
    5  * its documentation for any purpose and without fee is hereby
    6  * granted, provided that both the above copyright notice and this
    7  * permission notice appear in all copies, that both the above
    8  * copyright notice and this permission notice appear in all
    9  * supporting documentation, and that the name of M.I.T. not be used
   10  * in advertising or publicity pertaining to distribution of the
   11  * software without specific, written prior permission.  M.I.T. makes
   12  * no representations about the suitability of this software for any
   13  * purpose.  It is provided "as is" without express or implied
   14  * warranty.
   15  * 
   16  * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
   17  * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
   18  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
   19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
   20  * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   23  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   25  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   26  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  */
   29 
   30 #include <sys/cdefs.h>
   31 __FBSDID("$FreeBSD: releng/9.0/sys/i386/i386/perfmon.c 220433 2011-04-07 23:28:28Z jkim $");
   32 
   33 #include <sys/param.h>
   34 #include <sys/systm.h>
   35 #include <sys/conf.h>
   36 #include <sys/fcntl.h>
   37 #include <sys/kernel.h>
   38 
   39 #ifndef SMP
   40 #include <machine/cputypes.h>
   41 #endif
   42 #include <machine/clock.h>
   43 #include <machine/perfmon.h>
   44 #include <machine/specialreg.h>
   45 
   46 static int perfmon_inuse;
   47 static int perfmon_cpuok;
   48 #ifndef SMP
   49 static int msr_ctl[NPMC];
   50 #endif
   51 static int msr_pmc[NPMC];
   52 static unsigned int ctl_shadow[NPMC];
   53 static quad_t pmc_shadow[NPMC]; /* used when ctr is stopped on P5 */
   54 static int (*writectl)(int);
   55 #ifndef SMP
   56 static int writectl5(int);
   57 static int writectl6(int);
   58 #endif
   59 
   60 static d_close_t perfmon_close;
   61 static d_open_t perfmon_open;
   62 static d_ioctl_t perfmon_ioctl;
   63 
   64 /*
   65  * XXX perfmon_init_dev(void *) is a split from the perfmon_init() funtion. 
   66  * This solves a problem for DEVFS users.  It loads the "perfmon" driver after
   67  * the DEVFS subsystem has been kicked into action.  The SI_ORDER_ANY is to
   68  * assure that it is the most lowest priority task which, guarantees the
   69  * above.
   70  */
   71 static void perfmon_init_dev(void *);
   72 SYSINIT(cpu, SI_SUB_DRIVERS, SI_ORDER_ANY, perfmon_init_dev, NULL);
   73 
   74 static struct cdevsw perfmon_cdevsw = {
   75         .d_version =    D_VERSION,
   76         .d_flags =      D_NEEDGIANT,
   77         .d_open =       perfmon_open,
   78         .d_close =      perfmon_close,
   79         .d_ioctl =      perfmon_ioctl,
   80         .d_name =       "perfmon",
   81 };
   82 
   83 /*
   84  * Must be called after cpu_class is set up.
   85  */
   86 void
   87 perfmon_init(void)
   88 {
   89 #ifndef SMP
   90         switch(cpu_class) {
   91         case CPUCLASS_586:
   92                 perfmon_cpuok = 1;
   93                 msr_ctl[0] = MSR_P5_CESR;
   94                 msr_ctl[1] = MSR_P5_CESR;
   95                 msr_pmc[0] = MSR_P5_CTR0;
   96                 msr_pmc[1] = MSR_P5_CTR1;
   97                 writectl = writectl5;
   98                 break;
   99         case CPUCLASS_686:
  100                 perfmon_cpuok = 1;
  101                 msr_ctl[0] = MSR_EVNTSEL0;
  102                 msr_ctl[1] = MSR_EVNTSEL1;
  103                 msr_pmc[0] = MSR_PERFCTR0;
  104                 msr_pmc[1] = MSR_PERFCTR1;
  105                 writectl = writectl6;
  106                 break;
  107 
  108         default:
  109                 perfmon_cpuok = 0;
  110                 break;
  111         }
  112 #endif /* SMP */
  113 }
  114 
  115 static void
  116 perfmon_init_dev(dummy)
  117         void *dummy;
  118 {
  119         make_dev(&perfmon_cdevsw, 32, UID_ROOT, GID_KMEM, 0640, "perfmon");
  120 }
  121 
  122 int
  123 perfmon_avail(void)
  124 {
  125         return perfmon_cpuok;
  126 }
  127 
  128 int
  129 perfmon_setup(int pmc, unsigned int control)
  130 {
  131         register_t      saveintr;
  132 
  133         if (pmc < 0 || pmc >= NPMC)
  134                 return EINVAL;
  135 
  136         perfmon_inuse |= (1 << pmc);
  137         control &= ~(PMCF_SYS_FLAGS << 16);
  138         saveintr = intr_disable();
  139         ctl_shadow[pmc] = control;
  140         writectl(pmc);
  141         wrmsr(msr_pmc[pmc], pmc_shadow[pmc] = 0);
  142         intr_restore(saveintr);
  143         return 0;
  144 }
  145 
  146 int
  147 perfmon_get(int pmc, unsigned int *control)
  148 {
  149         if (pmc < 0 || pmc >= NPMC)
  150                 return EINVAL;
  151 
  152         if (perfmon_inuse & (1 << pmc)) {
  153                 *control = ctl_shadow[pmc];
  154                 return 0;
  155         }
  156         return EBUSY;           /* XXX reversed sense */
  157 }
  158 
  159 int
  160 perfmon_fini(int pmc)
  161 {
  162         if (pmc < 0 || pmc >= NPMC)
  163                 return EINVAL;
  164 
  165         if (perfmon_inuse & (1 << pmc)) {
  166                 perfmon_stop(pmc);
  167                 ctl_shadow[pmc] = 0;
  168                 perfmon_inuse &= ~(1 << pmc);
  169                 return 0;
  170         }
  171         return EBUSY;           /* XXX reversed sense */
  172 }
  173 
  174 int
  175 perfmon_start(int pmc)
  176 {
  177         register_t      saveintr;
  178 
  179         if (pmc < 0 || pmc >= NPMC)
  180                 return EINVAL;
  181 
  182         if (perfmon_inuse & (1 << pmc)) {
  183                 saveintr = intr_disable();
  184                 ctl_shadow[pmc] |= (PMCF_EN << 16);
  185                 wrmsr(msr_pmc[pmc], pmc_shadow[pmc]);
  186                 writectl(pmc);
  187                 intr_restore(saveintr);
  188                 return 0;
  189         }
  190         return EBUSY;
  191 }
  192 
  193 int
  194 perfmon_stop(int pmc)
  195 {
  196         register_t      saveintr;
  197 
  198         if (pmc < 0 || pmc >= NPMC)
  199                 return EINVAL;
  200 
  201         if (perfmon_inuse & (1 << pmc)) {
  202                 saveintr = intr_disable();
  203                 pmc_shadow[pmc] = rdmsr(msr_pmc[pmc]) & 0xffffffffffULL;
  204                 ctl_shadow[pmc] &= ~(PMCF_EN << 16);
  205                 writectl(pmc);
  206                 intr_restore(saveintr);
  207                 return 0;
  208         }
  209         return EBUSY;
  210 }
  211 
  212 int
  213 perfmon_read(int pmc, quad_t *val)
  214 {
  215         if (pmc < 0 || pmc >= NPMC)
  216                 return EINVAL;
  217 
  218         if (perfmon_inuse & (1 << pmc)) {
  219                 if (ctl_shadow[pmc] & (PMCF_EN << 16))
  220                         *val = rdmsr(msr_pmc[pmc]) & 0xffffffffffULL;
  221                 else
  222                         *val = pmc_shadow[pmc];
  223                 return 0;
  224         }
  225 
  226         return EBUSY;
  227 }
  228 
  229 int
  230 perfmon_reset(int pmc)
  231 {
  232         if (pmc < 0 || pmc >= NPMC)
  233                 return EINVAL;
  234 
  235         if (perfmon_inuse & (1 << pmc)) {
  236                 wrmsr(msr_pmc[pmc], pmc_shadow[pmc] = 0);
  237                 return 0;
  238         }
  239         return EBUSY;
  240 }
  241 
  242 #ifndef SMP
  243 /*
  244  * Unfortunately, the performance-monitoring registers are laid out
  245  * differently in the P5 and P6.  We keep everything in P6 format
  246  * internally (except for the event code), and convert to P5
  247  * format as needed on those CPUs.  The writectl function pointer
  248  * is set up to point to one of these functions by perfmon_init().
  249  */
  250 int
  251 writectl6(int pmc)
  252 {
  253         if (pmc > 0 && !(ctl_shadow[pmc] & (PMCF_EN << 16))) {
  254                 wrmsr(msr_ctl[pmc], 0);
  255         } else {
  256                 wrmsr(msr_ctl[pmc], ctl_shadow[pmc]);
  257         }
  258         return 0;
  259 }
  260 
  261 #define P5FLAG_P        0x200
  262 #define P5FLAG_E        0x100
  263 #define P5FLAG_USR      0x80
  264 #define P5FLAG_OS       0x40
  265 
  266 int
  267 writectl5(int pmc)
  268 {
  269         quad_t newval = 0;
  270 
  271         if (ctl_shadow[1] & (PMCF_EN << 16)) {
  272                 if (ctl_shadow[1] & (PMCF_USR << 16))
  273                         newval |= P5FLAG_USR << 16;
  274                 if (ctl_shadow[1] & (PMCF_OS << 16))
  275                         newval |= P5FLAG_OS << 16;
  276                 if (!(ctl_shadow[1] & (PMCF_E << 16)))
  277                         newval |= P5FLAG_E << 16;
  278                 newval |= (ctl_shadow[1] & 0x3f) << 16;
  279         }
  280         if (ctl_shadow[0] & (PMCF_EN << 16)) {
  281                 if (ctl_shadow[0] & (PMCF_USR << 16))
  282                         newval |= P5FLAG_USR;
  283                 if (ctl_shadow[0] & (PMCF_OS << 16))
  284                         newval |= P5FLAG_OS;
  285                 if (!(ctl_shadow[0] & (PMCF_E << 16)))
  286                         newval |= P5FLAG_E;
  287                 newval |= ctl_shadow[0] & 0x3f;
  288         }
  289 
  290         wrmsr(msr_ctl[0], newval);
  291         return 0;               /* XXX should check for unimplemented bits */
  292 }
  293 #endif /* !SMP */
  294 
  295 /*
  296  * Now the user-mode interface, called from a subdevice of mem.c.
  297  */
  298 static int writer;
  299 static int writerpmc;
  300 
  301 static int
  302 perfmon_open(struct cdev *dev, int flags, int fmt, struct thread *td)
  303 {
  304         if (!perfmon_cpuok)
  305                 return ENXIO;
  306 
  307         if (flags & FWRITE) {
  308                 if (writer) {
  309                         return EBUSY;
  310                 } else {
  311                         writer = 1;
  312                         writerpmc = 0;
  313                 }
  314         }
  315         return 0;
  316 }
  317 
  318 static int
  319 perfmon_close(struct cdev *dev, int flags, int fmt, struct thread *td)
  320 {
  321         if (flags & FWRITE) {
  322                 int i;
  323 
  324                 for (i = 0; i < NPMC; i++) {
  325                         if (writerpmc & (1 << i))
  326                                 perfmon_fini(i);
  327                 }
  328                 writer = 0;
  329         }
  330         return 0;
  331 }
  332 
  333 static int
  334 perfmon_ioctl(struct cdev *dev, u_long cmd, caddr_t param, int flags, struct thread *td)
  335 {
  336         struct pmc *pmc;
  337         struct pmc_data *pmcd;
  338         struct pmc_tstamp *pmct;
  339         uint64_t freq;
  340         int *ip;
  341         int rv;
  342 
  343         switch(cmd) {
  344         case PMIOSETUP:
  345                 if (!(flags & FWRITE))
  346                         return EPERM;
  347                 pmc = (struct pmc *)param;
  348 
  349                 rv = perfmon_setup(pmc->pmc_num, pmc->pmc_val);
  350                 if (!rv) {
  351                         writerpmc |= (1 << pmc->pmc_num);
  352                 }
  353                 break;
  354 
  355         case PMIOGET:
  356                 pmc = (struct pmc *)param;
  357                 rv = perfmon_get(pmc->pmc_num, &pmc->pmc_val);
  358                 break;
  359 
  360         case PMIOSTART:
  361                 if (!(flags & FWRITE))
  362                         return EPERM;
  363 
  364                 ip = (int *)param;
  365                 rv = perfmon_start(*ip);
  366                 break;
  367 
  368         case PMIOSTOP:
  369                 if (!(flags & FWRITE))
  370                         return EPERM;
  371 
  372                 ip = (int *)param;
  373                 rv = perfmon_stop(*ip);
  374                 break;
  375 
  376         case PMIORESET:
  377                 if (!(flags & FWRITE))
  378                         return EPERM;
  379 
  380                 ip = (int *)param;
  381                 rv = perfmon_reset(*ip);
  382                 break;
  383 
  384         case PMIOREAD:
  385                 pmcd = (struct pmc_data *)param;
  386                 rv = perfmon_read(pmcd->pmcd_num, &pmcd->pmcd_value);
  387                 break;
  388 
  389         case PMIOTSTAMP:
  390                 freq = atomic_load_acq_64(&tsc_freq);
  391                 if (freq == 0) {
  392                         rv = ENOTTY;
  393                         break;
  394                 }
  395                 pmct = (struct pmc_tstamp *)param;
  396                 /* XXX interface loses precision. */
  397                 pmct->pmct_rate = freq / 1000000;
  398                 pmct->pmct_value = rdtsc();
  399                 rv = 0;
  400                 break;
  401         default:
  402                 rv = ENOTTY;
  403         }
  404 
  405         return rv;
  406 }

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