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 AARCH64_BRK 0xd4200000 42 #define AARCH64_BRK_IMM16_SHIFT 5 43 #define AARCH64_BRK_IMM16_VAL (0x40d << AARCH64_BRK_IMM16_SHIFT) 44 #define FBT_PATCHVAL (AARCH64_BRK | AARCH64_BRK_IMM16_VAL) 45 #define FBT_AFRAMES 4 46 47 int 48 fbt_invop(uintptr_t addr, struct trapframe *frame, uintptr_t rval) 49 { 50 solaris_cpu_t *cpu; 51 fbt_probe_t *fbt; 52 53 cpu = &solaris_cpu[curcpu]; 54 fbt = fbt_probetab[FBT_ADDR2NDX(addr)]; 55 56 for (; fbt != NULL; fbt = fbt->fbtp_hashnext) { 57 if ((uintptr_t)fbt->fbtp_patchpoint != addr) 58 continue; 59 60 cpu->cpu_dtrace_caller = addr; 61 62 if (fbt->fbtp_roffset == 0) { 63 dtrace_probe(fbt->fbtp_id, frame->tf_x[0], 64 frame->tf_x[1], frame->tf_x[2], 65 frame->tf_x[3], frame->tf_x[4]); 66 } else { 67 dtrace_probe(fbt->fbtp_id, fbt->fbtp_roffset, rval, 68 0, 0, 0); 69 } 70 cpu->cpu_dtrace_caller = 0; 71 return (fbt->fbtp_savedval); 72 } 73 74 return (0); 75 } 76 77 void 78 fbt_patch_tracepoint(fbt_probe_t *fbt, fbt_patchval_t val) 79 { 80 vm_offset_t addr; 81 82 if (!arm64_get_writable_addr((vm_offset_t)fbt->fbtp_patchpoint, &addr)) 83 panic("%s: Unable to write new instruction", __func__); 84 85 *(fbt_patchval_t *)addr = val; 86 cpu_icache_sync_range((vm_offset_t)fbt->fbtp_patchpoint, 4); 87 } 88 89 int 90 fbt_provide_module_function(linker_file_t lf, int symindx, 91 linker_symval_t *symval, void *opaque) 92 { 93 fbt_probe_t *fbt, *retfbt; 94 uint32_t *target, *start; 95 uint32_t *instr, *limit; 96 const char *name; 97 char *modname; 98 bool found; 99 int offs; 100 101 modname = opaque; 102 name = symval->name; 103 104 /* Check if function is excluded from instrumentation */ 105 if (fbt_excluded(name)) 106 return (0); 107 108 /* 109 * Instrumenting certain exception handling functions can lead to FBT 110 * recursion, so exclude from instrumentation. 111 */ 112 if (strcmp(name, "handle_el1h_sync") == 0 || 113 strcmp(name, "do_el1h_sync") == 0) 114 return (1); 115 116 instr = (uint32_t *)(symval->value); 117 limit = (uint32_t *)(symval->value + symval->size); 118 119 /* 120 * Ignore any bti instruction at the start of the function 121 * we need to keep it there for any indirect branches calling 122 * the function on Armv8.5+ 123 */ 124 if ((*instr & BTI_MASK) == BTI_INSTR) 125 instr++; 126 127 /* Look for stp (pre-indexed) operation */ 128 found = false; 129 /* 130 * If the first instruction is a nop it's a specially marked 131 * asm function. We only support a nop first as it's not a normal 132 * part of the function prologue. 133 */ 134 if (*instr == NOP_INSTR) 135 found = true; 136 if (!found) { 137 for (; instr < limit; instr++) { 138 /* 139 * Some functions start with 140 * "stp xt1, xt2, [xn, <const>]!" 141 */ 142 if ((*instr & LDP_STP_MASK) == STP_64) { 143 /* 144 * Assume any other store of this type means we 145 * are past the function prolog. 146 */ 147 if (((*instr >> ADDR_SHIFT) & ADDR_MASK) == 31) 148 found = true; 149 break; 150 } 151 152 /* 153 * Some functions start with a "sub sp, sp, <const>" 154 * Sometimes the compiler will have a sub instruction 155 * that is not of the above type so don't stop if we 156 * see one. 157 */ 158 if ((*instr & SUB_MASK) == SUB_INSTR && 159 ((*instr >> SUB_RD_SHIFT) & SUB_R_MASK) == 31 && 160 ((*instr >> SUB_RN_SHIFT) & SUB_R_MASK) == 31) { 161 found = true; 162 break; 163 } 164 } 165 } 166 167 if (!found) 168 return (0); 169 170 fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO); 171 fbt->fbtp_name = name; 172 fbt->fbtp_id = dtrace_probe_create(fbt_id, modname, 173 name, FBT_ENTRY, FBT_AFRAMES, fbt); 174 fbt->fbtp_patchpoint = instr; 175 fbt->fbtp_ctl = lf; 176 fbt->fbtp_loadcnt = lf->loadcnt; 177 fbt->fbtp_savedval = *instr; 178 fbt->fbtp_patchval = FBT_PATCHVAL; 179 if ((*instr & SUB_MASK) == SUB_INSTR) 180 fbt->fbtp_rval = DTRACE_INVOP_SUB; 181 else 182 fbt->fbtp_rval = DTRACE_INVOP_STP; 183 fbt->fbtp_symindx = symindx; 184 185 fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)]; 186 fbt_probetab[FBT_ADDR2NDX(instr)] = fbt; 187 188 lf->fbt_nentries++; 189 190 retfbt = NULL; 191 again: 192 for (; instr < limit; instr++) { 193 if (*instr == RET_INSTR) 194 break; 195 else if ((*instr & B_MASK) == B_INSTR) { 196 offs = (*instr & B_DATA_MASK); 197 offs *= 4; 198 target = (instr + offs); 199 start = (uint32_t *)symval->value; 200 if (target >= limit || target < start) 201 break; 202 } 203 } 204 205 if (instr >= limit) 206 return (0); 207 208 /* 209 * We have a winner! 210 */ 211 fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO); 212 fbt->fbtp_name = name; 213 if (retfbt == NULL) { 214 fbt->fbtp_id = dtrace_probe_create(fbt_id, modname, 215 name, FBT_RETURN, FBT_AFRAMES, fbt); 216 } else { 217 retfbt->fbtp_probenext = fbt; 218 fbt->fbtp_id = retfbt->fbtp_id; 219 } 220 retfbt = fbt; 221 222 fbt->fbtp_patchpoint = instr; 223 fbt->fbtp_ctl = lf; 224 fbt->fbtp_loadcnt = lf->loadcnt; 225 fbt->fbtp_symindx = symindx; 226 if ((*instr & B_MASK) == B_INSTR) 227 fbt->fbtp_rval = DTRACE_INVOP_B; 228 else 229 fbt->fbtp_rval = DTRACE_INVOP_RET; 230 fbt->fbtp_roffset = (uintptr_t)instr - (uintptr_t)symval->value; 231 fbt->fbtp_savedval = *instr; 232 fbt->fbtp_patchval = FBT_PATCHVAL; 233 fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)]; 234 fbt_probetab[FBT_ADDR2NDX(instr)] = fbt; 235 236 lf->fbt_nentries++; 237 238 instr++; 239 goto again; 240 } 241