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 52 int 53 fbt_invop(uintptr_t addr, uintptr_t *stack, uintptr_t rval) 54 { 55 struct trapframe *frame = (struct trapframe *)stack; 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 fbt->fbtp_invop_cnt++; 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 /* PowerPC64 uses '.' prefixes on symbol names, ignore it. */ 120 if (name[0] == '.') 121 name++; 122 123 if (strncmp(name, "dtrace_", 7) == 0 && 124 strncmp(name, "dtrace_safe_", 12) != 0) { 125 /* 126 * Anything beginning with "dtrace_" may be called 127 * from probe context unless it explicitly indicates 128 * that it won't be called from probe context by 129 * using the prefix "dtrace_safe_". 130 */ 131 return (0); 132 } 133 134 if (name[0] == '_' && name[1] == '_') 135 return (0); 136 137 instr = (uint32_t *) symval->value; 138 limit = (uint32_t *) (symval->value + symval->size); 139 140 for (; instr < limit; instr++) 141 if (*instr == FBT_MFLR_R0) 142 break; 143 144 if (*instr != FBT_MFLR_R0) 145 return (0); 146 147 fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO); 148 fbt->fbtp_name = name; 149 fbt->fbtp_id = dtrace_probe_create(fbt_id, modname, 150 name, FBT_ENTRY, 7, fbt); 151 fbt->fbtp_patchpoint = instr; 152 fbt->fbtp_ctl = lf; 153 fbt->fbtp_loadcnt = lf->loadcnt; 154 fbt->fbtp_savedval = *instr; 155 fbt->fbtp_patchval = FBT_PATCHVAL; 156 fbt->fbtp_rval = DTRACE_INVOP_MFLR_R0; 157 fbt->fbtp_symindx = symindx; 158 159 fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)]; 160 fbt_probetab[FBT_ADDR2NDX(instr)] = fbt; 161 162 lf->fbt_nentries++; 163 164 retfbt = NULL; 165 again: 166 if (instr >= limit) 167 return (0); 168 169 /* 170 * We (desperately) want to avoid erroneously instrumenting a 171 * jump table. To determine if we're looking at a true instruction 172 * sequence or an inline jump table that happens to contain the same 173 * byte sequences, we resort to some heuristic sleeze: we treat this 174 * instruction as being contained within a pointer, and see if that 175 * pointer points to within the body of the function. If it does, we 176 * refuse to instrument it. 177 */ 178 { 179 uint32_t *ptr; 180 181 ptr = *(uint32_t **)instr; 182 183 if (ptr >= (uint32_t *) symval->value && ptr < limit) { 184 instr++; 185 goto again; 186 } 187 } 188 189 if (*instr != FBT_MTLR_R0) { 190 instr++; 191 goto again; 192 } 193 194 instr++; 195 196 for (j = 0; j < 12 && instr < limit; j++, instr++) { 197 if ((*instr == FBT_BCTR) || (*instr == FBT_BLR) || 198 FBT_IS_JUMP(*instr)) 199 break; 200 } 201 202 if (!(*instr == FBT_BCTR || *instr == FBT_BLR || FBT_IS_JUMP(*instr))) 203 goto again; 204 205 /* 206 * We have a winner! 207 */ 208 fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO); 209 fbt->fbtp_name = name; 210 211 if (retfbt == NULL) { 212 fbt->fbtp_id = dtrace_probe_create(fbt_id, modname, 213 name, FBT_RETURN, 7, fbt); 214 } else { 215 retfbt->fbtp_next = fbt; 216 fbt->fbtp_id = retfbt->fbtp_id; 217 } 218 219 retfbt = fbt; 220 fbt->fbtp_patchpoint = instr; 221 fbt->fbtp_ctl = lf; 222 fbt->fbtp_loadcnt = lf->loadcnt; 223 fbt->fbtp_symindx = symindx; 224 225 if (*instr == FBT_BCTR) 226 fbt->fbtp_rval = DTRACE_INVOP_BCTR; 227 else if (*instr == FBT_BLR) 228 fbt->fbtp_rval = DTRACE_INVOP_RET; 229 else 230 fbt->fbtp_rval = DTRACE_INVOP_JUMP; 231 232 fbt->fbtp_savedval = *instr; 233 fbt->fbtp_patchval = FBT_PATCHVAL; 234 fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)]; 235 fbt_probetab[FBT_ADDR2NDX(instr)] = fbt; 236 237 lf->fbt_nentries++; 238 239 instr += 4; 240 goto again; 241 } 242