1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 * 21 * Portions Copyright 2006-2008 John Birrell jb@freebsd.org 22 * Portions Copyright 2013 Justin Hibbits jhibbits@freebsd.org 23 * Portions Copyright 2013 Howard Su howardsu@freebsd.org 24 * Portions Copyright 2015 Ruslan Bukin <br@bsdpad.com> 25 * 26 * $FreeBSD$ 27 */ 28 29 /* 30 * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 31 * Use is subject to license terms. 32 */ 33 34 #include <sys/cdefs.h> 35 #include <sys/param.h> 36 37 #include <sys/dtrace.h> 38 39 #include "fbt.h" 40 41 #define FBT_PATCHVAL DTRACE_PATCHVAL 42 #define FBT_AFRAMES 4 43 44 int 45 fbt_invop(uintptr_t addr, struct trapframe *frame, uintptr_t rval) 46 { 47 solaris_cpu_t *cpu; 48 fbt_probe_t *fbt; 49 50 cpu = &solaris_cpu[curcpu]; 51 fbt = fbt_probetab[FBT_ADDR2NDX(addr)]; 52 53 for (; fbt != NULL; fbt = fbt->fbtp_hashnext) { 54 if ((uintptr_t)fbt->fbtp_patchpoint != addr) 55 continue; 56 57 cpu->cpu_dtrace_caller = addr; 58 59 if (fbt->fbtp_roffset == 0) { 60 dtrace_probe(fbt->fbtp_id, frame->tf_x[0], 61 frame->tf_x[1], frame->tf_x[2], 62 frame->tf_x[3], frame->tf_x[4]); 63 } else { 64 dtrace_probe(fbt->fbtp_id, fbt->fbtp_roffset, rval, 65 0, 0, 0); 66 } 67 cpu->cpu_dtrace_caller = 0; 68 return (fbt->fbtp_savedval); 69 } 70 71 return (0); 72 } 73 74 void 75 fbt_patch_tracepoint(fbt_probe_t *fbt, fbt_patchval_t val) 76 { 77 vm_offset_t addr; 78 79 if (!arm64_get_writable_addr((vm_offset_t)fbt->fbtp_patchpoint, &addr)) 80 panic("%s: Unable to write new instruction", __func__); 81 82 *(fbt_patchval_t *)addr = val; 83 cpu_icache_sync_range((vm_offset_t)fbt->fbtp_patchpoint, 4); 84 } 85 86 int 87 fbt_provide_module_function(linker_file_t lf, int symindx, 88 linker_symval_t *symval, void *opaque) 89 { 90 fbt_probe_t *fbt, *retfbt; 91 uint32_t *target, *start; 92 uint32_t *instr, *limit; 93 const char *name; 94 char *modname; 95 bool found; 96 int offs; 97 98 modname = opaque; 99 name = symval->name; 100 101 /* Check if function is excluded from instrumentation */ 102 if (fbt_excluded(name)) 103 return (0); 104 105 /* 106 * Instrumenting certain exception handling functions can lead to FBT 107 * recursion, so exclude from instrumentation. 108 */ 109 if (strcmp(name, "handle_el1h_sync") == 0 || 110 strcmp(name, "do_el1h_sync") == 0) 111 return (1); 112 113 instr = (uint32_t *)(symval->value); 114 limit = (uint32_t *)(symval->value + symval->size); 115 116 /* 117 * Ignore any bti instruction at the start of the function 118 * we need to keep it there for any indirect branches calling 119 * the function on Armv8.5+ 120 */ 121 if ((*instr & BTI_MASK) == BTI_INSTR) 122 instr++; 123 124 /* Look for stp (pre-indexed) operation */ 125 found = false; 126 /* 127 * If the first instruction is a nop it's a specially marked 128 * asm function. We only support a nop first as it's not a normal 129 * part of the function prologue. 130 */ 131 if (*instr == NOP_INSTR) 132 found = true; 133 for (; !found && instr < limit; instr++) { 134 /* 135 * Functions start with "stp xt1, xt2, [xn, <const>]!" or 136 * "sub sp, sp, <const>". 137 * 138 * Sometimes the compiler will have a sub instruction that is 139 * not of the above type so don't stop if we see one. 140 */ 141 if ((*instr & LDP_STP_MASK) == STP_64) { 142 /* 143 * Assume any other store of this type means we are 144 * past the function prologue. 145 */ 146 if (((*instr >> ADDR_SHIFT) & ADDR_MASK) == 31) 147 found = true; 148 } else if ((*instr & SUB_MASK) == SUB_INSTR && 149 ((*instr >> SUB_RD_SHIFT) & SUB_R_MASK) == 31 && 150 ((*instr >> SUB_RN_SHIFT) & SUB_R_MASK) == 31) 151 found = true; 152 } 153 154 if (!found) 155 return (0); 156 157 fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO); 158 fbt->fbtp_name = name; 159 fbt->fbtp_id = dtrace_probe_create(fbt_id, modname, 160 name, FBT_ENTRY, FBT_AFRAMES, fbt); 161 fbt->fbtp_patchpoint = instr; 162 fbt->fbtp_ctl = lf; 163 fbt->fbtp_loadcnt = lf->loadcnt; 164 fbt->fbtp_savedval = *instr; 165 fbt->fbtp_patchval = FBT_PATCHVAL; 166 if ((*instr & SUB_MASK) == SUB_INSTR) 167 fbt->fbtp_rval = DTRACE_INVOP_SUB; 168 else 169 fbt->fbtp_rval = DTRACE_INVOP_STP; 170 fbt->fbtp_symindx = symindx; 171 172 fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)]; 173 fbt_probetab[FBT_ADDR2NDX(instr)] = fbt; 174 175 lf->fbt_nentries++; 176 177 retfbt = NULL; 178 again: 179 for (; instr < limit; instr++) { 180 if (*instr == RET_INSTR) 181 break; 182 else if ((*instr & B_MASK) == B_INSTR) { 183 offs = (*instr & B_DATA_MASK); 184 offs *= 4; 185 target = (instr + offs); 186 start = (uint32_t *)symval->value; 187 if (target >= limit || target < start) 188 break; 189 } 190 } 191 192 if (instr >= limit) 193 return (0); 194 195 /* 196 * We have a winner! 197 */ 198 fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO); 199 fbt->fbtp_name = name; 200 if (retfbt == NULL) { 201 fbt->fbtp_id = dtrace_probe_create(fbt_id, modname, 202 name, FBT_RETURN, FBT_AFRAMES, fbt); 203 } else { 204 retfbt->fbtp_probenext = fbt; 205 fbt->fbtp_id = retfbt->fbtp_id; 206 } 207 retfbt = fbt; 208 209 fbt->fbtp_patchpoint = instr; 210 fbt->fbtp_ctl = lf; 211 fbt->fbtp_loadcnt = lf->loadcnt; 212 fbt->fbtp_symindx = symindx; 213 if ((*instr & B_MASK) == B_INSTR) 214 fbt->fbtp_rval = DTRACE_INVOP_B; 215 else 216 fbt->fbtp_rval = DTRACE_INVOP_RET; 217 fbt->fbtp_roffset = (uintptr_t)instr - (uintptr_t)symval->value; 218 fbt->fbtp_savedval = *instr; 219 fbt->fbtp_patchval = FBT_PATCHVAL; 220 fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)]; 221 fbt_probetab[FBT_ADDR2NDX(instr)] = fbt; 222 223 lf->fbt_nentries++; 224 225 instr++; 226 goto again; 227 } 228