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/param.h> 34 #include <sys/systm.h> 35 #include <sys/bus.h> 36 #include <sys/pmc.h> 37 38 #include <vm/vm.h> 39 #include <vm/pmap.h> 40 41 #include <machine/cpu.h> 42 #include <machine/cputypes.h> 43 #include <machine/intr_machdep.h> /* For x86/apicvar.h */ 44 #include <machine/md_var.h> 45 #include <machine/pmc_mdep.h> 46 #include <machine/stack.h> 47 #include <machine/vmparam.h> 48 49 #include <x86/apicvar.h> 50 51 #include "hwpmc_soft.h" 52 53 /* 54 * Attempt to walk a user call stack using a too-simple algorithm. 55 * In the general case we need unwind information associated with 56 * the executable to be able to walk the user stack. 57 * 58 * We are handed a trap frame laid down at the time the PMC interrupt 59 * was taken. If the application is using frame pointers, the saved 60 * PC value could be: 61 * a. at the beginning of a function before the stack frame is laid 62 * down, 63 * b. just before a 'ret', after the stack frame has been taken off, 64 * c. somewhere else in the function with a valid stack frame being 65 * present, 66 * 67 * If the application is not using frame pointers, this algorithm will 68 * fail to yield an interesting call chain. 69 * 70 * TODO: figure out a way to use unwind information. 71 */ 72 73 int 74 pmc_save_user_callchain(uintptr_t *cc, int nframes, struct trapframe *tf) 75 { 76 int n; 77 uint32_t instr; 78 uintptr_t fp, oldfp, pc, r, sp; 79 80 KASSERT(TRAPF_USERMODE(tf), ("[x86,%d] Not a user trap frame tf=%p", 81 __LINE__, (void *) tf)); 82 83 pc = PMC_TRAPFRAME_TO_PC(tf); 84 oldfp = fp = PMC_TRAPFRAME_TO_FP(tf); 85 sp = PMC_TRAPFRAME_TO_USER_SP(tf); 86 87 *cc++ = pc; n = 1; 88 89 r = fp + sizeof(uintptr_t); /* points to return address */ 90 91 if (!PMC_IN_USERSPACE(pc)) 92 return (n); 93 94 if (copyin((void *) pc, &instr, sizeof(instr)) != 0) 95 return (n); 96 97 if (PMC_AT_FUNCTION_PROLOGUE_PUSH_BP(instr) || 98 PMC_AT_FUNCTION_EPILOGUE_RET(instr)) { /* ret */ 99 if (copyin((void *) sp, &pc, sizeof(pc)) != 0) 100 return (n); 101 } else if (PMC_AT_FUNCTION_PROLOGUE_MOV_SP_BP(instr)) { 102 sp += sizeof(uintptr_t); 103 if (copyin((void *) sp, &pc, sizeof(pc)) != 0) 104 return (n); 105 } else if (copyin((void *) r, &pc, sizeof(pc)) != 0 || 106 copyin((void *) fp, &fp, sizeof(fp)) != 0) 107 return (n); 108 109 for (; n < nframes;) { 110 if (pc == 0 || !PMC_IN_USERSPACE(pc)) 111 break; 112 113 *cc++ = pc; n++; 114 115 if (fp < oldfp) 116 break; 117 118 r = fp + sizeof(uintptr_t); /* address of return address */ 119 oldfp = fp; 120 121 if (copyin((void *) r, &pc, sizeof(pc)) != 0 || 122 copyin((void *) fp, &fp, sizeof(fp)) != 0) 123 break; 124 } 125 126 return (n); 127 } 128 129 /* 130 * Walking the kernel call stack. 131 * 132 * We are handed the trap frame laid down at the time the PMC 133 * interrupt was taken. The saved PC could be: 134 * a. in the lowlevel trap handler, meaning that there isn't a C stack 135 * to traverse, 136 * b. at the beginning of a function before the stack frame is laid 137 * down, 138 * c. just before a 'ret', after the stack frame has been taken off, 139 * d. somewhere else in a function with a valid stack frame being 140 * present. 141 * 142 * In case (d), the previous frame pointer is at [%ebp]/[%rbp] and 143 * the return address is at [%ebp+4]/[%rbp+8]. 144 * 145 * For cases (b) and (c), the return address is at [%esp]/[%rsp] and 146 * the frame pointer doesn't need to be changed when going up one 147 * level in the stack. 148 * 149 * For case (a), we check if the PC lies in low-level trap handling 150 * code, and if so we terminate our trace. 151 */ 152 153 int __nosanitizeaddress __nosanitizememory 154 pmc_save_kernel_callchain(uintptr_t *cc, int nframes, struct trapframe *tf) 155 { 156 uintptr_t fp, pc, ra, sp; 157 uint32_t instr; 158 int n; 159 160 KASSERT(TRAPF_USERMODE(tf) == 0,("[x86,%d] not a kernel backtrace", 161 __LINE__)); 162 163 pc = PMC_TRAPFRAME_TO_PC(tf); 164 fp = PMC_TRAPFRAME_TO_FP(tf); 165 sp = PMC_TRAPFRAME_TO_KERNEL_SP(tf); 166 167 *cc++ = pc; 168 ra = fp + sizeof(uintptr_t); /* points to return address */ 169 170 if (nframes <= 1) 171 return (1); 172 173 if (PMC_IN_TRAP_HANDLER(pc) || !PMC_IN_KERNEL(pc) || 174 !PMC_IN_KERNEL_STACK(ra) || !PMC_IN_KERNEL_STACK(sp) || 175 !PMC_IN_KERNEL_STACK(fp)) 176 return (1); 177 178 instr = *(uint32_t *)pc; 179 180 /* 181 * Determine whether the interrupted function was in the 182 * processing of either laying down its stack frame or taking 183 * it off. 184 * 185 * If we haven't started laying down a stack frame, or are 186 * just about to return, then our caller's address is at 187 * *sp, and we don't have a frame to unwind. 188 */ 189 if (PMC_AT_FUNCTION_PROLOGUE_PUSH_BP(instr) || 190 PMC_AT_FUNCTION_EPILOGUE_RET(instr)) 191 pc = *(uintptr_t *) sp; 192 else if (PMC_AT_FUNCTION_PROLOGUE_MOV_SP_BP(instr)) { 193 /* 194 * The code was midway through laying down a frame. 195 * At this point sp[0] has a frame back pointer, 196 * and the caller's address is therefore at sp[1]. 197 */ 198 sp += sizeof(uintptr_t); 199 if (!PMC_IN_KERNEL_STACK(sp)) 200 return (1); 201 pc = *(uintptr_t *)sp; 202 } else { 203 /* 204 * Not in the function prologue or epilogue. 205 */ 206 pc = *(uintptr_t *)ra; 207 fp = *(uintptr_t *)fp; 208 } 209 210 for (n = 1; n < nframes; n++) { 211 *cc++ = pc; 212 213 if (PMC_IN_TRAP_HANDLER(pc)) 214 break; 215 216 ra = fp + sizeof(uintptr_t); 217 if (!PMC_IN_KERNEL_STACK(fp) || !PMC_IN_KERNEL_STACK(ra)) 218 break; 219 pc = *(uintptr_t *)ra; 220 fp = *(uintptr_t *)fp; 221 } 222 223 return (n); 224 } 225 226 /* 227 * Machine dependent initialization for x86 class platforms. 228 */ 229 struct pmc_mdep * 230 pmc_md_initialize(void) 231 { 232 int i; 233 struct pmc_mdep *md; 234 235 /* determine the CPU kind */ 236 if (cpu_vendor_id == CPU_VENDOR_AMD || 237 cpu_vendor_id == CPU_VENDOR_HYGON) 238 md = pmc_amd_initialize(); 239 else if (cpu_vendor_id == CPU_VENDOR_INTEL) 240 md = pmc_intel_initialize(); 241 else 242 return (NULL); 243 244 /* disallow sampling if we do not have an LAPIC */ 245 if (md != NULL && !lapic_enable_pmc()) 246 for (i = 0; i < md->pmd_nclass; i++) { 247 if (i == PMC_CLASS_INDEX_SOFT) 248 continue; 249 md->pmd_classdep[i].pcd_caps &= ~PMC_CAP_INTERRUPT; 250 } 251 252 return (md); 253 } 254 255 void 256 pmc_md_finalize(struct pmc_mdep *md) 257 { 258 259 lapic_disable_pmc(); 260 if (cpu_vendor_id == CPU_VENDOR_AMD || 261 cpu_vendor_id == CPU_VENDOR_HYGON) 262 pmc_amd_finalize(md); 263 else if (cpu_vendor_id == CPU_VENDOR_INTEL) 264 pmc_intel_finalize(md); 265 else 266 KASSERT(0, ("[x86,%d] Unknown vendor", __LINE__)); 267 } 268