1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1993 5 * The Regents of the University of California. 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 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * @(#)subr_prof.c 8.3 (Berkeley) 9/23/93 32 */ 33 34 #include <sys/cdefs.h> 35 __FBSDID("$FreeBSD$"); 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/sysproto.h> 40 #include <sys/kernel.h> 41 #include <sys/lock.h> 42 #include <sys/mutex.h> 43 #include <sys/proc.h> 44 #include <sys/resourcevar.h> 45 #include <sys/sysctl.h> 46 47 #include <machine/cpu.h> 48 49 /* 50 * Profiling system call. 51 * 52 * The scale factor is a fixed point number with 16 bits of fraction, so that 53 * 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling. 54 */ 55 #ifndef _SYS_SYSPROTO_H_ 56 struct profil_args { 57 caddr_t samples; 58 size_t size; 59 size_t offset; 60 u_int scale; 61 }; 62 #endif 63 /* ARGSUSED */ 64 int 65 sys_profil(struct thread *td, struct profil_args *uap) 66 { 67 struct uprof *upp; 68 struct proc *p; 69 70 if (uap->scale > (1 << 16)) 71 return (EINVAL); 72 73 p = td->td_proc; 74 if (uap->scale == 0) { 75 PROC_LOCK(p); 76 stopprofclock(p); 77 PROC_UNLOCK(p); 78 return (0); 79 } 80 PROC_LOCK(p); 81 upp = &td->td_proc->p_stats->p_prof; 82 PROC_PROFLOCK(p); 83 upp->pr_off = uap->offset; 84 upp->pr_scale = uap->scale; 85 upp->pr_base = uap->samples; 86 upp->pr_size = uap->size; 87 PROC_PROFUNLOCK(p); 88 startprofclock(p); 89 PROC_UNLOCK(p); 90 91 return (0); 92 } 93 94 /* 95 * Scale is a fixed-point number with the binary point 16 bits 96 * into the value, and is <= 1.0. pc is at most 32 bits, so the 97 * intermediate result is at most 48 bits. 98 */ 99 #define PC_TO_INDEX(pc, prof) \ 100 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \ 101 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1) 102 103 /* 104 * Collect user-level profiling statistics; called on a profiling tick, 105 * when a process is running in user-mode. This routine may be called 106 * from an interrupt context. We perform the update with an AST 107 * that will vector us to trap() with a context in which copyin and 108 * copyout will work. Trap will then call addupc_task(). 109 * 110 * Note that we may (rarely) not get around to the AST soon enough, and 111 * lose profile ticks when the next tick overwrites this one, but in this 112 * case the system is overloaded and the profile is probably already 113 * inaccurate. 114 */ 115 void 116 addupc_intr(struct thread *td, uintfptr_t pc, u_int ticks) 117 { 118 struct uprof *prof; 119 120 if (ticks == 0) 121 return; 122 prof = &td->td_proc->p_stats->p_prof; 123 PROC_PROFLOCK(td->td_proc); 124 if (pc < prof->pr_off || PC_TO_INDEX(pc, prof) >= prof->pr_size) { 125 PROC_PROFUNLOCK(td->td_proc); 126 return; /* out of range; ignore */ 127 } 128 129 PROC_PROFUNLOCK(td->td_proc); 130 td->td_profil_addr = pc; 131 td->td_profil_ticks = ticks; 132 td->td_pflags |= TDP_OWEUPC; 133 thread_lock(td); 134 td->td_flags |= TDF_ASTPENDING; 135 thread_unlock(td); 136 } 137 138 /* 139 * Actually update the profiling statistics. If the update fails, we 140 * simply turn off profiling. 141 */ 142 void 143 addupc_task(struct thread *td, uintfptr_t pc, u_int ticks) 144 { 145 struct proc *p = td->td_proc; 146 struct uprof *prof; 147 caddr_t addr; 148 u_int i; 149 u_short v; 150 int stop = 0; 151 152 if (ticks == 0) 153 return; 154 155 PROC_LOCK(p); 156 if (!(p->p_flag & P_PROFIL)) { 157 PROC_UNLOCK(p); 158 return; 159 } 160 p->p_profthreads++; 161 prof = &p->p_stats->p_prof; 162 PROC_PROFLOCK(p); 163 if (pc < prof->pr_off || 164 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) { 165 PROC_PROFUNLOCK(p); 166 goto out; 167 } 168 169 addr = prof->pr_base + i; 170 PROC_PROFUNLOCK(p); 171 PROC_UNLOCK(p); 172 if (copyin(addr, &v, sizeof(v)) == 0) { 173 v += ticks; 174 if (copyout(&v, addr, sizeof(v)) == 0) { 175 PROC_LOCK(p); 176 goto out; 177 } 178 } 179 stop = 1; 180 PROC_LOCK(p); 181 182 out: 183 if (--p->p_profthreads == 0) { 184 if (p->p_flag & P_STOPPROF) { 185 wakeup(&p->p_profthreads); 186 p->p_flag &= ~P_STOPPROF; 187 stop = 0; 188 } 189 } 190 if (stop) 191 stopprofclock(p); 192 PROC_UNLOCK(p); 193 } 194