sys/i386/i386/prof_machdep.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 1996 Bruce D. Evans.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 __FBSDID("$FreeBSD$");
  31
  32 #ifdef GUPROF
  33 #include "opt_i586_guprof.h"
  34 #include "opt_perfmon.h"
  35
  36 #include <sys/param.h>
  37 #include <sys/systm.h>
  38 #include <sys/bus.h>
  39 #include <sys/cpu.h>
  40 #include <sys/eventhandler.h>
  41 #include <sys/gmon.h>
  42 #include <sys/kernel.h>
  43 #include <sys/smp.h>
  44 #include <sys/sysctl.h>
  45
  46 #include <machine/clock.h>
  47 #include <machine/perfmon.h>
  48 #include <machine/timerreg.h>
  49
  50 #define CPUTIME_CLOCK_UNINITIALIZED     0
  51 #define CPUTIME_CLOCK_I8254             1
  52 #define CPUTIME_CLOCK_TSC               2
  53 #define CPUTIME_CLOCK_I586_PMC          3
  54 #define CPUTIME_CLOCK_I8254_SHIFT       7
  55
  56 int     cputime_bias = 1;       /* initialize for locality of reference */
  57
  58 static int      cputime_clock = CPUTIME_CLOCK_UNINITIALIZED;
  59 #if defined(PERFMON) && defined(I586_PMC_GUPROF)
  60 static u_int    cputime_clock_pmc_conf = I586_PMC_GUPROF;
  61 static int      cputime_clock_pmc_init;
  62 static struct gmonparam saved_gmp;
  63 #endif
  64 #if defined(I586_CPU) || defined(I686_CPU)
  65 static int      cputime_prof_active;
  66 #endif
  67 #endif /* GUPROF */
  68
  69 #ifdef __GNUCLIKE_ASM
  70 #if defined(SMP) && defined(GUPROF)
  71 #define MPLOCK "                                                \n\
  72         movl    $1,%edx                                         \n\
  73 9:                                                              \n\
  74         xorl    %eax,%eax                                       \n\
  75         lock                                                    \n\
  76         cmpxchgl %edx,mcount_lock                               \n\
  77         jne     9b                                              \n"
  78 #define MPUNLOCK "movl  $0,mcount_lock                          \n"
  79 #else /* !(SMP && GUPROF) */
  80 #define MPLOCK
  81 #define MPUNLOCK
  82 #endif /* SMP && GUPROF */
  83
  84 __asm("                                                         \n\
  85 GM_STATE        =       0                                       \n\
  86 GMON_PROF_OFF   =       3                                       \n\
  87                                                                 \n\
  88         .text                                                   \n\
  89         .p2align 4,0x90                                         \n\
  90         .globl  __mcount                                        \n\
  91         .type   __mcount,@function                              \n\
  92 __mcount:                                                       \n\
  93         #                                                       \n\
  94         # Check that we are profiling.  Do it early for speed.  \n\
  95         #                                                       \n\
  96         cmpl    $GMON_PROF_OFF,_gmonparam+GM_STATE              \n\
  97         je      .mcount_exit                                    \n\
  98         #                                                       \n\
  99         # __mcount is the same as [.]mcount except the caller   \n\
 100         # hasn't changed the stack except to call here, so the  \n\
 101         # caller's raddr is above our raddr.                    \n\
 102         #                                                       \n\
 103         movl    4(%esp),%edx                                    \n\
 104         jmp     .got_frompc                                     \n\
 105                                                                 \n\
 106         .p2align 4,0x90                                         \n\
 107         .globl  .mcount                                         \n\
 108 .mcount:                                                        \n\
 109         cmpl    $GMON_PROF_OFF,_gmonparam+GM_STATE              \n\
 110         je      .mcount_exit                                    \n\
 111         #                                                       \n\
 112         # The caller's stack frame has already been built, so   \n\
 113         # %ebp is the caller's frame pointer.  The caller's     \n\
 114         # raddr is in the caller's frame following the caller's \n\
 115         # caller's frame pointer.                               \n\
 116         #                                                       \n\
 117         movl    4(%ebp),%edx                                    \n\
 118 .got_frompc:                                                    \n\
 119         #                                                       \n\
 120         # Our raddr is the caller's pc.                         \n\
 121         #                                                       \n\
 122         movl    (%esp),%eax                                     \n\
 123                                                                 \n\
 124         pushfl                                                  \n\
 125         pushl   %eax                                            \n\
 126         pushl   %edx                                            \n\
 127         cli                                                     \n"
 128         MPLOCK "                                                \n\
 129         call    mcount                                          \n"
 130         MPUNLOCK "                                              \n\
 131         addl    $8,%esp                                         \n\
 132         popfl                                                   \n\
 133 .mcount_exit:                                                   \n\
 134         ret     $0                                              \n\
 135 ");
 136
 137 void    __mcount(void);
 138 void    (*__mcountp)(void) = __mcount;
 139 #else /* !__GNUCLIKE_ASM */
 140 #error "this file needs to be ported to your compiler"
 141 #endif /* __GNUCLIKE_ASM */
 142
 143 #ifdef GUPROF
 144 /*
 145  * [.]mexitcount saves the return register(s), loads selfpc and calls
 146  * mexitcount(selfpc) to do the work.  Someday it should be in a machine
 147  * dependent file together with cputime(), __mcount and [.]mcount.  cputime()
 148  * can't just be put in machdep.c because it has to be compiled without -pg.
 149  */
 150 #ifdef __GNUCLIKE_ASM
 151 __asm("                                                         \n\
 152         .text                                                   \n\
 153 #                                                               \n\
 154 # Dummy label to be seen when gprof -u hides [.]mexitcount.     \n\
 155 #                                                               \n\
 156         .p2align 4,0x90                                         \n\
 157         .globl  __mexitcount                                    \n\
 158         .type   __mexitcount,@function                          \n\
 159 __mexitcount:                                                   \n\
 160         nop                                                     \n\
 161                                                                 \n\
 162 GMON_PROF_HIRES =       4                                       \n\
 163                                                                 \n\
 164         .p2align 4,0x90                                         \n\
 165         .globl  .mexitcount                                     \n\
 166 .mexitcount:                                                    \n\
 167         cmpl    $GMON_PROF_HIRES,_gmonparam+GM_STATE            \n\
 168         jne     .mexitcount_exit                                \n\
 169         pushl   %edx                                            \n\
 170         pushl   %eax                                            \n\
 171         movl    8(%esp),%eax                                    \n\
 172         pushfl                                                  \n\
 173         pushl   %eax                                            \n\
 174         cli                                                     \n"
 175         MPLOCK "                                                \n\
 176         call    mexitcount                                      \n"
 177         MPUNLOCK "                                              \n\
 178         addl    $4,%esp                                         \n\
 179         popfl                                                   \n\
 180         popl    %eax                                            \n\
 181         popl    %edx                                            \n\
 182 .mexitcount_exit:                                               \n\
 183         ret     $0                                              \n\
 184 ");
 185 #endif /* __GNUCLIKE_ASM */
 186
 187 void    __mexitcount(void);
 188 void    (*__mexitcountp)(void) = __mexitcount;
 189
 190 /*
 191  * Return the time elapsed since the last call.  The units are machine-
 192  * dependent.
 193  */
 194 int
 195 cputime()
 196 {
 197         u_int count;
 198         int delta;
 199 #if (defined(I586_CPU) || defined(I686_CPU)) && \
 200     defined(PERFMON) && defined(I586_PMC_GUPROF) && !defined(SMP)
 201         u_quad_t event_count;
 202 #endif
 203         u_char high, low;
 204         static u_int prev_count;
 205
 206 #if defined(I586_CPU) || defined(I686_CPU)
 207         if (cputime_clock == CPUTIME_CLOCK_TSC) {
 208                 /*
 209                  * Scale the TSC a little to make cputime()'s frequency
 210                  * fit in an int, assuming that the TSC frequency fits
 211                  * in a u_int.  Use a fixed scale since dynamic scaling
 212                  * would be slower and we can't really use the low bit
 213                  * of precision.
 214                  */
 215                 count = (u_int)rdtsc() & ~1u;
 216                 delta = (int)(count - prev_count) >> 1;
 217                 prev_count = count;
 218                 return (delta);
 219         }
 220 #if defined(PERFMON) && defined(I586_PMC_GUPROF) && !defined(SMP)
 221         if (cputime_clock == CPUTIME_CLOCK_I586_PMC) {
 222                 /*
 223                  * XXX permon_read() should be inlined so that the
 224                  * perfmon module doesn't need to be compiled with
 225                  * profiling disabled and so that it is fast.
 226                  */
 227                 perfmon_read(0, &event_count);
 228
 229                 count = (u_int)event_count;
 230                 delta = (int)(count - prev_count);
 231                 prev_count = count;
 232                 return (delta);
 233         }
 234 #endif /* PERFMON && I586_PMC_GUPROF && !SMP */
 235 #endif /* I586_CPU || I686_CPU */
 236
 237         /*
 238          * Read the current value of the 8254 timer counter 0.
 239          */
 240         outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH);
 241         low = inb(TIMER_CNTR0);
 242         high = inb(TIMER_CNTR0);
 243         count = ((high << 8) | low) << CPUTIME_CLOCK_I8254_SHIFT;
 244
 245         /*
 246          * The timer counts down from TIMER_CNTR0_MAX to 0 and then resets.
 247          * While profiling is enabled, this routine is called at least twice
 248          * per timer reset (for mcounting and mexitcounting hardclock()),
 249          * so at most one reset has occurred since the last call, and one
 250          * has occurred iff the current count is larger than the previous
 251          * count.  This allows counter underflow to be detected faster
 252          * than in microtime().
 253          */
 254         delta = prev_count - count;
 255         prev_count = count;
 256         if ((int) delta <= 0)
 257                 return (delta + (i8254_max_count << CPUTIME_CLOCK_I8254_SHIFT));
 258         return (delta);
 259 }
 260
 261 static int
 262 sysctl_machdep_cputime_clock(SYSCTL_HANDLER_ARGS)
 263 {
 264         int clock;
 265         int error;
 266 #if defined(PERFMON) && defined(I586_PMC_GUPROF)
 267         int event;
 268         struct pmc pmc;
 269 #endif
 270
 271         clock = cputime_clock;
 272 #if defined(PERFMON) && defined(I586_PMC_GUPROF)
 273         if (clock == CPUTIME_CLOCK_I586_PMC) {
 274                 pmc.pmc_val = cputime_clock_pmc_conf;
 275                 clock += pmc.pmc_event;
 276         }
 277 #endif
 278         error = sysctl_handle_opaque(oidp, &clock, sizeof clock, req);
 279         if (error == 0 && req->newptr != NULL) {
 280 #if defined(PERFMON) && defined(I586_PMC_GUPROF)
 281                 if (clock >= CPUTIME_CLOCK_I586_PMC) {
 282                         event = clock - CPUTIME_CLOCK_I586_PMC;
 283                         if (event >= 256)
 284                                 return (EINVAL);
 285                         pmc.pmc_num = 0;
 286                         pmc.pmc_event = event;
 287                         pmc.pmc_unit = 0;
 288                         pmc.pmc_flags = PMCF_E | PMCF_OS | PMCF_USR;
 289                         pmc.pmc_mask = 0;
 290                         cputime_clock_pmc_conf = pmc.pmc_val;
 291                         cputime_clock = CPUTIME_CLOCK_I586_PMC;
 292                 } else
 293 #endif
 294                 {
 295                         if (clock < 0 || clock >= CPUTIME_CLOCK_I586_PMC)
 296                                 return (EINVAL);
 297                         cputime_clock = clock;
 298                 }
 299         }
 300         return (error);
 301 }
 302
 303 SYSCTL_PROC(_machdep, OID_AUTO, cputime_clock,
 304     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 0, sizeof(u_int),
 305     sysctl_machdep_cputime_clock, "I",
 306     "");
 307
 308 /*
 309  * The start and stop routines need not be here since we turn off profiling
 310  * before calling them.  They are here for convenience.
 311  */
 312
 313 void
 314 startguprof(gp)
 315         struct gmonparam *gp;
 316 {
 317 #if defined(I586_CPU) || defined(I686_CPU)
 318         uint64_t freq;
 319
 320         freq = atomic_load_acq_64(&tsc_freq);
 321         if (cputime_clock == CPUTIME_CLOCK_UNINITIALIZED) {
 322                 if (freq != 0 && mp_ncpus == 1)
 323                         cputime_clock = CPUTIME_CLOCK_TSC;
 324                 else
 325                         cputime_clock = CPUTIME_CLOCK_I8254;
 326         }
 327         if (cputime_clock == CPUTIME_CLOCK_TSC) {
 328                 gp->profrate = freq >> 1;
 329                 cputime_prof_active = 1;
 330         } else
 331                 gp->profrate = i8254_freq << CPUTIME_CLOCK_I8254_SHIFT;
 332 #if defined(PERFMON) && defined(I586_PMC_GUPROF)
 333         if (cputime_clock == CPUTIME_CLOCK_I586_PMC) {
 334                 if (perfmon_avail() &&
 335                     perfmon_setup(0, cputime_clock_pmc_conf) == 0) {
 336                         if (perfmon_start(0) != 0)
 337                                 perfmon_fini(0);
 338                         else {
 339                                 /* XXX 1 event == 1 us. */
 340                                 gp->profrate = 1000000;
 341
 342                                 saved_gmp = *gp;
 343
 344                                 /* Zap overheads.  They are invalid. */
 345                                 gp->cputime_overhead = 0;
 346                                 gp->mcount_overhead = 0;
 347                                 gp->mcount_post_overhead = 0;
 348                                 gp->mcount_pre_overhead = 0;
 349                                 gp->mexitcount_overhead = 0;
 350                                 gp->mexitcount_post_overhead = 0;
 351                                 gp->mexitcount_pre_overhead = 0;
 352
 353                                 cputime_clock_pmc_init = TRUE;
 354                         }
 355                 }
 356         }
 357 #endif /* PERFMON && I586_PMC_GUPROF */
 358 #else /* !(I586_CPU || I686_CPU) */
 359         if (cputime_clock == CPUTIME_CLOCK_UNINITIALIZED)
 360                 cputime_clock = CPUTIME_CLOCK_I8254;
 361         gp->profrate = i8254_freq << CPUTIME_CLOCK_I8254_SHIFT;
 362 #endif /* I586_CPU || I686_CPU */
 363         cputime_bias = 0;
 364         cputime();
 365 }
 366
 367 void
 368 stopguprof(gp)
 369         struct gmonparam *gp;
 370 {
 371 #if defined(PERFMON) && defined(I586_PMC_GUPROF)
 372         if (cputime_clock_pmc_init) {
 373                 *gp = saved_gmp;
 374                 perfmon_fini(0);
 375                 cputime_clock_pmc_init = FALSE;
 376         }
 377 #endif
 378 #if defined(I586_CPU) || defined(I686_CPU)
 379         if (cputime_clock == CPUTIME_CLOCK_TSC)
 380                 cputime_prof_active = 0;
 381 #endif
 382 }
 383
 384 #if defined(I586_CPU) || defined(I686_CPU)
 385 /* If the cpu frequency changed while profiling, report a warning. */
 386 static void
 387 tsc_freq_changed(void *arg, const struct cf_level *level, int status)
 388 {
 389
 390         /*
 391          * If there was an error during the transition or
 392          * TSC is P-state invariant, don't do anything.
 393          */
 394         if (status != 0 || tsc_is_invariant)
 395                 return;
 396         if (cputime_prof_active && cputime_clock == CPUTIME_CLOCK_TSC)
 397                 printf("warning: cpu freq changed while profiling active\n");
 398 }
 399
 400 EVENTHANDLER_DEFINE(cpufreq_post_change, tsc_freq_changed, NULL,
 401     EVENTHANDLER_PRI_ANY);
 402 #endif /* I586_CPU || I686_CPU */
 403
 404 #endif /* GUPROF */