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 * 24 * $FreeBSD$ 25 * 26 */ 27 28 /* 29 * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 30 * Use is subject to license terms. 31 */ 32 33 #include <sys/cdefs.h> 34 #include <sys/param.h> 35 #include <sys/dtrace.h> 36 #include <machine/md_var.h> 37 38 #include "fbt.h" 39 40 #define FBT_PATCHVAL 0x7c810808 41 #define FBT_MFLR_R0 0x7c0802a6 42 #define FBT_MTLR_R0 0x7c0803a6 43 #define FBT_BLR 0x4e800020 44 #define FBT_BCTR 0x4e800030 45 #define FBT_BRANCH 0x48000000 46 #define FBT_BR_MASK 0x03fffffc 47 #define FBT_IS_JUMP(instr) ((instr & ~FBT_BR_MASK) == FBT_BRANCH) 48 49 #define FBT_ENTRY "entry" 50 #define FBT_RETURN "return" 51 #define FBT_AFRAMES 7 52 53 int 54 fbt_invop(uintptr_t addr, uintptr_t *stack, uintptr_t rval) 55 { 56 struct trapframe *frame = (struct trapframe *)stack; 57 solaris_cpu_t *cpu = &solaris_cpu[curcpu]; 58 fbt_probe_t *fbt = fbt_probetab[FBT_ADDR2NDX(addr)]; 59 uintptr_t tmp; 60 61 for (; fbt != NULL; fbt = fbt->fbtp_hashnext) { 62 if ((uintptr_t)fbt->fbtp_patchpoint == addr) { 63 if (fbt->fbtp_roffset == 0) { 64 cpu->cpu_dtrace_caller = addr; 65 66 dtrace_probe(fbt->fbtp_id, frame->fixreg[3], 67 frame->fixreg[4], frame->fixreg[5], 68 frame->fixreg[6], frame->fixreg[7]); 69 70 cpu->cpu_dtrace_caller = 0; 71 } else { 72 73 dtrace_probe(fbt->fbtp_id, fbt->fbtp_roffset, 74 rval, 0, 0, 0); 75 /* 76 * The caller doesn't have the fbt item, so 77 * fixup tail calls here. 78 */ 79 if (fbt->fbtp_rval == DTRACE_INVOP_JUMP) { 80 frame->srr0 = (uintptr_t)fbt->fbtp_patchpoint; 81 tmp = fbt->fbtp_savedval & FBT_BR_MASK; 82 /* Sign extend. */ 83 if (tmp & 0x02000000) 84 #ifdef __powerpc64__ 85 tmp |= 0xfffffffffc000000ULL; 86 #else 87 tmp |= 0xfc000000UL; 88 #endif 89 frame->srr0 += tmp; 90 } 91 cpu->cpu_dtrace_caller = 0; 92 } 93 94 return (fbt->fbtp_rval); 95 } 96 } 97 98 return (0); 99 } 100 101 void 102 fbt_patch_tracepoint(fbt_probe_t *fbt, fbt_patchval_t val) 103 { 104 105 *fbt->fbtp_patchpoint = val; 106 __syncicache(fbt->fbtp_patchpoint, 4); 107 } 108 109 int 110 fbt_provide_module_function(linker_file_t lf, int symindx, 111 linker_symval_t *symval, void *opaque) 112 { 113 char *modname = opaque; 114 const char *name = symval->name; 115 fbt_probe_t *fbt, *retfbt; 116 int j; 117 uint32_t *instr, *limit; 118 119 #ifdef __powerpc64__ 120 /* 121 * PowerPC64 uses '.' prefixes on symbol names, ignore it, but only 122 * allow symbols with the '.' prefix, so that we don't get the function 123 * descriptor instead. 124 */ 125 if (name[0] == '.') 126 name++; 127 else 128 return (0); 129 #endif 130 131 if (strncmp(name, "dtrace_", 7) == 0 && 132 strncmp(name, "dtrace_safe_", 12) != 0) { 133 /* 134 * Anything beginning with "dtrace_" may be called 135 * from probe context unless it explicitly indicates 136 * that it won't be called from probe context by 137 * using the prefix "dtrace_safe_". 138 */ 139 return (0); 140 } 141 142 if (name[0] == '_' && name[1] == '_') 143 return (0); 144 145 instr = (uint32_t *) symval->value; 146 limit = (uint32_t *) (symval->value + symval->size); 147 148 for (; instr < limit; instr++) 149 if (*instr == FBT_MFLR_R0) 150 break; 151 152 if (*instr != FBT_MFLR_R0) 153 return (0); 154 155 fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO); 156 fbt->fbtp_name = name; 157 fbt->fbtp_id = dtrace_probe_create(fbt_id, modname, 158 name, FBT_ENTRY, FBT_AFRAMES, fbt); 159 fbt->fbtp_patchpoint = instr; 160 fbt->fbtp_ctl = lf; 161 fbt->fbtp_loadcnt = lf->loadcnt; 162 fbt->fbtp_savedval = *instr; 163 fbt->fbtp_patchval = FBT_PATCHVAL; 164 fbt->fbtp_rval = DTRACE_INVOP_MFLR_R0; 165 fbt->fbtp_symindx = symindx; 166 167 fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)]; 168 fbt_probetab[FBT_ADDR2NDX(instr)] = fbt; 169 170 lf->fbt_nentries++; 171 172 retfbt = NULL; 173 again: 174 if (instr >= limit) 175 return (0); 176 177 /* 178 * We (desperately) want to avoid erroneously instrumenting a 179 * jump table. To determine if we're looking at a true instruction 180 * sequence or an inline jump table that happens to contain the same 181 * byte sequences, we resort to some heuristic sleeze: we treat this 182 * instruction as being contained within a pointer, and see if that 183 * pointer points to within the body of the function. If it does, we 184 * refuse to instrument it. 185 */ 186 { 187 uint32_t *ptr; 188 189 ptr = *(uint32_t **)instr; 190 191 if (ptr >= (uint32_t *) symval->value && ptr < limit) { 192 instr++; 193 goto again; 194 } 195 } 196 197 if (*instr != FBT_MTLR_R0) { 198 instr++; 199 goto again; 200 } 201 202 instr++; 203 204 for (j = 0; j < 12 && instr < limit; j++, instr++) { 205 if ((*instr == FBT_BCTR) || (*instr == FBT_BLR) || 206 FBT_IS_JUMP(*instr)) 207 break; 208 } 209 210 if (!(*instr == FBT_BCTR || *instr == FBT_BLR || FBT_IS_JUMP(*instr))) 211 goto again; 212 213 /* 214 * We have a winner! 215 */ 216 fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO); 217 fbt->fbtp_name = name; 218 219 if (retfbt == NULL) { 220 fbt->fbtp_id = dtrace_probe_create(fbt_id, modname, 221 name, FBT_RETURN, FBT_AFRAMES, fbt); 222 } else { 223 retfbt->fbtp_next = fbt; 224 fbt->fbtp_id = retfbt->fbtp_id; 225 } 226 227 retfbt = fbt; 228 fbt->fbtp_patchpoint = instr; 229 fbt->fbtp_ctl = lf; 230 fbt->fbtp_loadcnt = lf->loadcnt; 231 fbt->fbtp_symindx = symindx; 232 233 if (*instr == FBT_BCTR) 234 fbt->fbtp_rval = DTRACE_INVOP_BCTR; 235 else if (*instr == FBT_BLR) 236 fbt->fbtp_rval = DTRACE_INVOP_RET; 237 else 238 fbt->fbtp_rval = DTRACE_INVOP_JUMP; 239 240 fbt->fbtp_roffset = 241 (uintptr_t)((uint8_t *)instr - (uint8_t *)symval->value); 242 243 fbt->fbtp_savedval = *instr; 244 fbt->fbtp_patchval = FBT_PATCHVAL; 245 fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)]; 246 fbt_probetab[FBT_ADDR2NDX(instr)] = fbt; 247 248 lf->fbt_nentries++; 249 250 instr += 4; 251 goto again; 252 } 253