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 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/sysproto.h> 38 #include <sys/kernel.h> 39 #include <sys/lock.h> 40 #include <sys/mutex.h> 41 #include <sys/proc.h> 42 #include <sys/resourcevar.h> 43 #include <sys/sysctl.h> 44 45 #include <machine/cpu.h> 46 47 /* 48 * Profiling system call. 49 * 50 * The scale factor is a fixed point number with 16 bits of fraction, so that 51 * 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling. 52 */ 53 #ifndef _SYS_SYSPROTO_H_ 54 struct profil_args { 55 caddr_t samples; 56 size_t size; 57 size_t offset; 58 u_int scale; 59 }; 60 #endif 61 /* ARGSUSED */ 62 int 63 sys_profil(struct thread *td, struct profil_args *uap) 64 { 65 struct uprof *upp; 66 struct proc *p; 67 68 if (uap->scale > (1 << 16)) 69 return (EINVAL); 70 71 p = td->td_proc; 72 if (uap->scale == 0) { 73 PROC_LOCK(p); 74 stopprofclock(p); 75 PROC_UNLOCK(p); 76 return (0); 77 } 78 PROC_LOCK(p); 79 upp = &td->td_proc->p_stats->p_prof; 80 PROC_PROFLOCK(p); 81 upp->pr_off = uap->offset; 82 upp->pr_scale = uap->scale; 83 upp->pr_base = uap->samples; 84 upp->pr_size = uap->size; 85 PROC_PROFUNLOCK(p); 86 startprofclock(p); 87 PROC_UNLOCK(p); 88 89 return (0); 90 } 91 92 /* 93 * Scale is a fixed-point number with the binary point 16 bits 94 * into the value, and is <= 1.0. pc is at most 32 bits, so the 95 * intermediate result is at most 48 bits. 96 */ 97 #define PC_TO_INDEX(pc, prof) \ 98 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \ 99 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1) 100 101 /* 102 * Collect user-level profiling statistics; called on a profiling tick, 103 * when a process is running in user-mode. This routine may be called 104 * from an interrupt context. We perform the update with an AST 105 * that will vector us to trap() with a context in which copyin and 106 * copyout will work. Trap will then call addupc_task(). 107 * 108 * Note that we may (rarely) not get around to the AST soon enough, and 109 * lose profile ticks when the next tick overwrites this one, but in this 110 * case the system is overloaded and the profile is probably already 111 * inaccurate. 112 */ 113 void 114 addupc_intr(struct thread *td, uintfptr_t pc, u_int ticks) 115 { 116 struct uprof *prof; 117 118 if (ticks == 0) 119 return; 120 prof = &td->td_proc->p_stats->p_prof; 121 PROC_PROFLOCK(td->td_proc); 122 if (pc < prof->pr_off || PC_TO_INDEX(pc, prof) >= prof->pr_size) { 123 PROC_PROFUNLOCK(td->td_proc); 124 return; /* out of range; ignore */ 125 } 126 127 PROC_PROFUNLOCK(td->td_proc); 128 td->td_profil_addr = pc; 129 td->td_profil_ticks = ticks; 130 td->td_pflags |= TDP_OWEUPC; 131 ast_sched(td, TDA_OWEUPC); 132 } 133 134 /* 135 * Actually update the profiling statistics. If the update fails, we 136 * simply turn off profiling. 137 */ 138 void 139 addupc_task(struct thread *td, uintfptr_t pc, u_int ticks) 140 { 141 struct proc *p = td->td_proc; 142 struct uprof *prof; 143 caddr_t addr; 144 u_int i; 145 u_short v; 146 int stop = 0; 147 148 if (ticks == 0) 149 return; 150 151 PROC_LOCK(p); 152 if (!(p->p_flag & P_PROFIL)) { 153 PROC_UNLOCK(p); 154 return; 155 } 156 p->p_profthreads++; 157 prof = &p->p_stats->p_prof; 158 PROC_PROFLOCK(p); 159 if (pc < prof->pr_off || 160 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) { 161 PROC_PROFUNLOCK(p); 162 goto out; 163 } 164 165 addr = prof->pr_base + i; 166 PROC_PROFUNLOCK(p); 167 PROC_UNLOCK(p); 168 if (copyin(addr, &v, sizeof(v)) == 0) { 169 v += ticks; 170 if (copyout(&v, addr, sizeof(v)) == 0) { 171 PROC_LOCK(p); 172 goto out; 173 } 174 } 175 stop = 1; 176 PROC_LOCK(p); 177 178 out: 179 if (--p->p_profthreads == 0) { 180 if (p->p_flag & P_STOPPROF) { 181 wakeup(&p->p_profthreads); 182 p->p_flag &= ~P_STOPPROF; 183 stop = 0; 184 } 185 } 186 if (stop) 187 stopprofclock(p); 188 PROC_UNLOCK(p); 189 } 190