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- /*-
- * SPDX-License-Identifier: BSD-3-Clause
- *
- * Copyright (c) 1983, 1992, 1993
- * The Regents of the University of California. 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.
- * 3. Neither the name of the University nor the names of its contributors
- * may be used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
- */
- #include <sys/cdefs.h>
- __FBSDID("$FreeBSD$");
- #include <sys/param.h>
- #include <sys/gmon.h>
- #ifdef _KERNEL
- #ifndef GUPROF
- #include <sys/systm.h>
- #endif
- #include <vm/vm.h>
- #include <vm/vm_param.h>
- #include <vm/pmap.h>
- #endif
- /*
- * mcount is called on entry to each function compiled with the profiling
- * switch set. _mcount(), which is declared in a machine-dependent way
- * with _MCOUNT_DECL, does the actual work and is either inlined into a
- * C routine or called by an assembly stub. In any case, this magic is
- * taken care of by the MCOUNT definition in <machine/profile.h>.
- *
- * _mcount updates data structures that represent traversals of the
- * program's call graph edges. frompc and selfpc are the return
- * address and function address that represents the given call graph edge.
- *
- * Note: the original BSD code used the same variable (frompcindex) for
- * both frompcindex and frompc. Any reasonable, modern compiler will
- * perform this optimization.
- */
- /* _mcount; may be static, inline, etc */
- _MCOUNT_DECL(uintfptr_t frompc, uintfptr_t selfpc)
- {
- #ifdef GUPROF
- int delta;
- #endif
- fptrdiff_t frompci;
- u_short *frompcindex;
- struct tostruct *top, *prevtop;
- struct gmonparam *p;
- long toindex;
- #ifdef _KERNEL
- MCOUNT_DECL(s)
- #endif
- p = &_gmonparam;
- #ifndef GUPROF /* XXX */
- /*
- * check that we are profiling
- * and that we aren't recursively invoked.
- */
- if (p->state != GMON_PROF_ON)
- return;
- #endif
- #ifdef _KERNEL
- MCOUNT_ENTER(s);
- #else
- p->state = GMON_PROF_BUSY;
- #endif
- #ifdef _KERNEL
- /* De-relocate any addresses in a (single) trampoline. */
- #ifdef MCOUNT_DETRAMP
- MCOUNT_DETRAMP(frompc);
- MCOUNT_DETRAMP(selfpc);
- #endif
- /*
- * When we are called from an exception handler, frompc may be
- * a user address. Convert such frompc's to some representation
- * in kernel address space.
- */
- #ifdef MCOUNT_FROMPC_USER
- frompc = MCOUNT_FROMPC_USER(frompc);
- #elif defined(MCOUNT_USERPC)
- /*
- * For separate address spaces, we can only guess that addresses
- * in the range known to us are actually kernel addresses. Outside
- * of this range, conerting to the user address is fail-safe.
- */
- if (frompc < p->lowpc || frompc - p->lowpc >= p->textsize)
- frompc = MCOUNT_USERPC;
- #endif
- #endif /* _KERNEL */
- frompci = frompc - p->lowpc;
- if (frompci >= p->textsize)
- goto done;
- #ifdef GUPROF
- if (p->state == GMON_PROF_HIRES) {
- /*
- * Count the time since cputime() was previously called
- * against `frompc'. Compensate for overheads.
- *
- * cputime() sets its prev_count variable to the count when
- * it is called. This in effect starts a counter for
- * the next period of execution (normally from now until
- * the next call to mcount() or mexitcount()). We set
- * cputime_bias to compensate for our own overhead.
- *
- * We use the usual sampling counters since they can be
- * located efficiently. 4-byte counters are usually
- * necessary. gprof will add up the scattered counts
- * just like it does for statistical profiling. All
- * counts are signed so that underflow in the subtractions
- * doesn't matter much (negative counts are normally
- * compensated for by larger counts elsewhere). Underflow
- * shouldn't occur, but may be caused by slightly wrong
- * calibrations or from not clearing cputime_bias.
- */
- delta = cputime() - cputime_bias - p->mcount_pre_overhead;
- cputime_bias = p->mcount_post_overhead;
- KCOUNT(p, frompci) += delta;
- *p->cputime_count += p->cputime_overhead;
- *p->mcount_count += p->mcount_overhead;
- }
- #endif /* GUPROF */
- #ifdef _KERNEL
- /*
- * When we are called from an exception handler, frompc is faked
- * to be for where the exception occurred. We've just solidified
- * the count for there. Now convert frompci to an index that
- * represents the kind of exception so that interruptions appear
- * in the call graph as calls from those index instead of calls
- * from all over.
- */
- frompc = MCOUNT_FROMPC_INTR(selfpc);
- if ((frompc - p->lowpc) < p->textsize)
- frompci = frompc - p->lowpc;
- #endif
- /*
- * check that frompc is a reasonable pc value.
- * for example: signal catchers get called from the stack,
- * not from text space. too bad.
- */
- if (frompci >= p->textsize)
- goto done;
- frompcindex = &p->froms[frompci / (p->hashfraction * sizeof(*p->froms))];
- toindex = *frompcindex;
- if (toindex == 0) {
- /*
- * first time traversing this arc
- */
- toindex = ++p->tos[0].link;
- if (toindex >= p->tolimit)
- /* halt further profiling */
- goto overflow;
- *frompcindex = toindex;
- top = &p->tos[toindex];
- top->selfpc = selfpc;
- top->count = 1;
- top->link = 0;
- goto done;
- }
- top = &p->tos[toindex];
- if (top->selfpc == selfpc) {
- /*
- * arc at front of chain; usual case.
- */
- top->count++;
- goto done;
- }
- /*
- * have to go looking down chain for it.
- * top points to what we are looking at,
- * prevtop points to previous top.
- * we know it is not at the head of the chain.
- */
- for (; /* goto done */; ) {
- if (top->link == 0) {
- /*
- * top is end of the chain and none of the chain
- * had top->selfpc == selfpc.
- * so we allocate a new tostruct
- * and link it to the head of the chain.
- */
- toindex = ++p->tos[0].link;
- if (toindex >= p->tolimit)
- goto overflow;
- top = &p->tos[toindex];
- top->selfpc = selfpc;
- top->count = 1;
- top->link = *frompcindex;
- *frompcindex = toindex;
- goto done;
- }
- /*
- * otherwise, check the next arc on the chain.
- */
- prevtop = top;
- top = &p->tos[top->link];
- if (top->selfpc == selfpc) {
- /*
- * there it is.
- * increment its count
- * move it to the head of the chain.
- */
- top->count++;
- toindex = prevtop->link;
- prevtop->link = top->link;
- top->link = *frompcindex;
- *frompcindex = toindex;
- goto done;
- }
- }
- done:
- #ifdef _KERNEL
- MCOUNT_EXIT(s);
- #else
- p->state = GMON_PROF_ON;
- #endif
- return;
- overflow:
- p->state = GMON_PROF_ERROR;
- #ifdef _KERNEL
- MCOUNT_EXIT(s);
- #endif
- return;
- }
- /*
- * Actual definition of mcount function. Defined in <machine/profile.h>,
- * which is included by <sys/gmon.h>.
- */
- MCOUNT
- #ifdef GUPROF
- void
- mexitcount(uintfptr_t selfpc)
- {
- struct gmonparam *p;
- uintfptr_t selfpcdiff;
- p = &_gmonparam;
- #ifdef MCOUNT_DETRAMP
- MCOUNT_DETRAMP(selfpc);
- #endif
- selfpcdiff = selfpc - (uintfptr_t)p->lowpc;
- if (selfpcdiff < p->textsize) {
- int delta;
- /*
- * Count the time since cputime() was previously called
- * against `selfpc'. Compensate for overheads.
- */
- delta = cputime() - cputime_bias - p->mexitcount_pre_overhead;
- cputime_bias = p->mexitcount_post_overhead;
- KCOUNT(p, selfpcdiff) += delta;
- *p->cputime_count += p->cputime_overhead;
- *p->mexitcount_count += p->mexitcount_overhead;
- }
- }
- #ifndef __GNUCLIKE_ASM
- #error "This file uses null asms to prevent timing loops being optimized away."
- #endif
- void
- empty_loop(void)
- {
- int i;
- for (i = 0; i < CALIB_SCALE; i++)
- __asm __volatile("");
- }
- void
- nullfunc(void)
- {
- __asm __volatile("");
- }
- void
- nullfunc_loop(void)
- {
- int i;
- for (i = 0; i < CALIB_SCALE; i++)
- nullfunc();
- }
- #endif /* GUPROF */
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