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