1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2005,2008 Joseph Koshy 5 * Copyright (c) 2007 The FreeBSD Foundation 6 * All rights reserved. 7 * 8 * Portions of this software were developed by A. Joseph Koshy under 9 * sponsorship from the FreeBSD Foundation and Google, Inc. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/bus.h> 39 #include <sys/pmc.h> 40 41 #include <vm/vm.h> 42 #include <vm/pmap.h> 43 44 #include <machine/cpu.h> 45 #include <machine/cputypes.h> 46 #include <machine/intr_machdep.h> /* For x86/apicvar.h */ 47 #include <machine/md_var.h> 48 #include <machine/pmc_mdep.h> 49 #include <machine/stack.h> 50 #include <machine/vmparam.h> 51 52 #include <x86/apicvar.h> 53 54 #include "hwpmc_soft.h" 55 56 /* 57 * Attempt to walk a user call stack using a too-simple algorithm. 58 * In the general case we need unwind information associated with 59 * the executable to be able to walk the user stack. 60 * 61 * We are handed a trap frame laid down at the time the PMC interrupt 62 * was taken. If the application is using frame pointers, the saved 63 * PC value could be: 64 * a. at the beginning of a function before the stack frame is laid 65 * down, 66 * b. just before a 'ret', after the stack frame has been taken off, 67 * c. somewhere else in the function with a valid stack frame being 68 * present, 69 * 70 * If the application is not using frame pointers, this algorithm will 71 * fail to yield an interesting call chain. 72 * 73 * TODO: figure out a way to use unwind information. 74 */ 75 76 int 77 pmc_save_user_callchain(uintptr_t *cc, int nframes, struct trapframe *tf) 78 { 79 int n; 80 uint32_t instr; 81 uintptr_t fp, oldfp, pc, r, sp; 82 83 KASSERT(TRAPF_USERMODE(tf), ("[x86,%d] Not a user trap frame tf=%p", 84 __LINE__, (void *) tf)); 85 86 pc = PMC_TRAPFRAME_TO_PC(tf); 87 oldfp = fp = PMC_TRAPFRAME_TO_FP(tf); 88 sp = PMC_TRAPFRAME_TO_USER_SP(tf); 89 90 *cc++ = pc; n = 1; 91 92 r = fp + sizeof(uintptr_t); /* points to return address */ 93 94 if (!PMC_IN_USERSPACE(pc)) 95 return (n); 96 97 if (copyin((void *) pc, &instr, sizeof(instr)) != 0) 98 return (n); 99 100 if (PMC_AT_FUNCTION_PROLOGUE_PUSH_BP(instr) || 101 PMC_AT_FUNCTION_EPILOGUE_RET(instr)) { /* ret */ 102 if (copyin((void *) sp, &pc, sizeof(pc)) != 0) 103 return (n); 104 } else if (PMC_AT_FUNCTION_PROLOGUE_MOV_SP_BP(instr)) { 105 sp += sizeof(uintptr_t); 106 if (copyin((void *) sp, &pc, sizeof(pc)) != 0) 107 return (n); 108 } else if (copyin((void *) r, &pc, sizeof(pc)) != 0 || 109 copyin((void *) fp, &fp, sizeof(fp)) != 0) 110 return (n); 111 112 for (; n < nframes;) { 113 if (pc == 0 || !PMC_IN_USERSPACE(pc)) 114 break; 115 116 *cc++ = pc; n++; 117 118 if (fp < oldfp) 119 break; 120 121 r = fp + sizeof(uintptr_t); /* address of return address */ 122 oldfp = fp; 123 124 if (copyin((void *) r, &pc, sizeof(pc)) != 0 || 125 copyin((void *) fp, &fp, sizeof(fp)) != 0) 126 break; 127 } 128 129 return (n); 130 } 131 132 /* 133 * Walking the kernel call stack. 134 * 135 * We are handed the trap frame laid down at the time the PMC 136 * interrupt was taken. The saved PC could be: 137 * a. in the lowlevel trap handler, meaning that there isn't a C stack 138 * to traverse, 139 * b. at the beginning of a function before the stack frame is laid 140 * down, 141 * c. just before a 'ret', after the stack frame has been taken off, 142 * d. somewhere else in a function with a valid stack frame being 143 * present. 144 * 145 * In case (d), the previous frame pointer is at [%ebp]/[%rbp] and 146 * the return address is at [%ebp+4]/[%rbp+8]. 147 * 148 * For cases (b) and (c), the return address is at [%esp]/[%rsp] and 149 * the frame pointer doesn't need to be changed when going up one 150 * level in the stack. 151 * 152 * For case (a), we check if the PC lies in low-level trap handling 153 * code, and if so we terminate our trace. 154 */ 155 156 int __nosanitizeaddress __nosanitizememory 157 pmc_save_kernel_callchain(uintptr_t *cc, int nframes, struct trapframe *tf) 158 { 159 uintptr_t fp, pc, ra, sp; 160 uint32_t instr; 161 int n; 162 163 KASSERT(TRAPF_USERMODE(tf) == 0,("[x86,%d] not a kernel backtrace", 164 __LINE__)); 165 166 pc = PMC_TRAPFRAME_TO_PC(tf); 167 fp = PMC_TRAPFRAME_TO_FP(tf); 168 sp = PMC_TRAPFRAME_TO_KERNEL_SP(tf); 169 170 *cc++ = pc; 171 ra = fp + sizeof(uintptr_t); /* points to return address */ 172 173 if (nframes <= 1) 174 return (1); 175 176 if (PMC_IN_TRAP_HANDLER(pc) || !PMC_IN_KERNEL(pc) || 177 !PMC_IN_KERNEL_STACK(ra) || !PMC_IN_KERNEL_STACK(sp) || 178 !PMC_IN_KERNEL_STACK(fp)) 179 return (1); 180 181 instr = *(uint32_t *)pc; 182 183 /* 184 * Determine whether the interrupted function was in the 185 * processing of either laying down its stack frame or taking 186 * it off. 187 * 188 * If we haven't started laying down a stack frame, or are 189 * just about to return, then our caller's address is at 190 * *sp, and we don't have a frame to unwind. 191 */ 192 if (PMC_AT_FUNCTION_PROLOGUE_PUSH_BP(instr) || 193 PMC_AT_FUNCTION_EPILOGUE_RET(instr)) 194 pc = *(uintptr_t *) sp; 195 else if (PMC_AT_FUNCTION_PROLOGUE_MOV_SP_BP(instr)) { 196 /* 197 * The code was midway through laying down a frame. 198 * At this point sp[0] has a frame back pointer, 199 * and the caller's address is therefore at sp[1]. 200 */ 201 sp += sizeof(uintptr_t); 202 if (!PMC_IN_KERNEL_STACK(sp)) 203 return (1); 204 pc = *(uintptr_t *)sp; 205 } else { 206 /* 207 * Not in the function prologue or epilogue. 208 */ 209 pc = *(uintptr_t *)ra; 210 fp = *(uintptr_t *)fp; 211 } 212 213 for (n = 1; n < nframes; n++) { 214 *cc++ = pc; 215 216 if (PMC_IN_TRAP_HANDLER(pc)) 217 break; 218 219 ra = fp + sizeof(uintptr_t); 220 if (!PMC_IN_KERNEL_STACK(fp) || !PMC_IN_KERNEL_STACK(ra)) 221 break; 222 pc = *(uintptr_t *)ra; 223 fp = *(uintptr_t *)fp; 224 } 225 226 return (n); 227 } 228 229 /* 230 * Machine dependent initialization for x86 class platforms. 231 */ 232 struct pmc_mdep * 233 pmc_md_initialize(void) 234 { 235 int i; 236 struct pmc_mdep *md; 237 238 /* determine the CPU kind */ 239 if (cpu_vendor_id == CPU_VENDOR_AMD || 240 cpu_vendor_id == CPU_VENDOR_HYGON) 241 md = pmc_amd_initialize(); 242 else if (cpu_vendor_id == CPU_VENDOR_INTEL) 243 md = pmc_intel_initialize(); 244 else 245 return (NULL); 246 247 /* disallow sampling if we do not have an LAPIC */ 248 if (md != NULL && !lapic_enable_pmc()) 249 for (i = 0; i < md->pmd_nclass; i++) { 250 if (i == PMC_CLASS_INDEX_SOFT) 251 continue; 252 md->pmd_classdep[i].pcd_caps &= ~PMC_CAP_INTERRUPT; 253 } 254 255 return (md); 256 } 257 258 void 259 pmc_md_finalize(struct pmc_mdep *md) 260 { 261 262 lapic_disable_pmc(); 263 if (cpu_vendor_id == CPU_VENDOR_AMD || 264 cpu_vendor_id == CPU_VENDOR_HYGON) 265 pmc_amd_finalize(md); 266 else if (cpu_vendor_id == CPU_VENDOR_INTEL) 267 pmc_intel_finalize(md); 268 else 269 KASSERT(0, ("[x86,%d] Unknown vendor", __LINE__)); 270 } 271