2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2005,2008 Joseph Koshy
5 * Copyright (c) 2007 The FreeBSD Foundation
8 * Portions of this software were developed by A. Joseph Koshy under
9 * sponsorship from the FreeBSD Foundation and Google, Inc.
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
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.
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
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
36 #include <sys/param.h>
40 #include <sys/systm.h>
42 #include <machine/cpu.h>
43 #include <machine/cputypes.h>
44 #include <machine/intr_machdep.h>
45 #if (__FreeBSD_version >= 1100000)
46 #include <x86/apicvar.h>
48 #include <machine/apicvar.h>
50 #include <machine/pmc_mdep.h>
51 #include <machine/md_var.h>
54 #include <vm/vm_param.h>
57 #include "hwpmc_soft.h"
60 * Attempt to walk a user call stack using a too-simple algorithm.
61 * In the general case we need unwind information associated with
62 * the executable to be able to walk the user stack.
64 * We are handed a trap frame laid down at the time the PMC interrupt
65 * was taken. If the application is using frame pointers, the saved
67 * a. at the beginning of a function before the stack frame is laid
69 * b. just before a 'ret', after the stack frame has been taken off,
70 * c. somewhere else in the function with a valid stack frame being
73 * If the application is not using frame pointers, this algorithm will
74 * fail to yield an interesting call chain.
76 * TODO: figure out a way to use unwind information.
80 pmc_save_user_callchain(uintptr_t *cc, int nframes, struct trapframe *tf)
84 uintptr_t fp, oldfp, pc, r, sp;
86 KASSERT(TRAPF_USERMODE(tf), ("[x86,%d] Not a user trap frame tf=%p",
87 __LINE__, (void *) tf));
89 pc = PMC_TRAPFRAME_TO_PC(tf);
90 oldfp = fp = PMC_TRAPFRAME_TO_FP(tf);
91 sp = PMC_TRAPFRAME_TO_USER_SP(tf);
95 r = fp + sizeof(uintptr_t); /* points to return address */
97 if (!PMC_IN_USERSPACE(pc))
100 if (copyin((void *) pc, &instr, sizeof(instr)) != 0)
103 if (PMC_AT_FUNCTION_PROLOGUE_PUSH_BP(instr) ||
104 PMC_AT_FUNCTION_EPILOGUE_RET(instr)) { /* ret */
105 if (copyin((void *) sp, &pc, sizeof(pc)) != 0)
107 } else if (PMC_AT_FUNCTION_PROLOGUE_MOV_SP_BP(instr)) {
108 sp += sizeof(uintptr_t);
109 if (copyin((void *) sp, &pc, sizeof(pc)) != 0)
111 } else if (copyin((void *) r, &pc, sizeof(pc)) != 0 ||
112 copyin((void *) fp, &fp, sizeof(fp)) != 0)
115 for (; n < nframes;) {
116 if (pc == 0 || !PMC_IN_USERSPACE(pc))
124 r = fp + sizeof(uintptr_t); /* address of return address */
127 if (copyin((void *) r, &pc, sizeof(pc)) != 0 ||
128 copyin((void *) fp, &fp, sizeof(fp)) != 0)
136 * Walking the kernel call stack.
138 * We are handed the trap frame laid down at the time the PMC
139 * interrupt was taken. The saved PC could be:
140 * a. in the lowlevel trap handler, meaning that there isn't a C stack
142 * b. at the beginning of a function before the stack frame is laid
144 * c. just before a 'ret', after the stack frame has been taken off,
145 * d. somewhere else in a function with a valid stack frame being
148 * In case (d), the previous frame pointer is at [%ebp]/[%rbp] and
149 * the return address is at [%ebp+4]/[%rbp+8].
151 * For cases (b) and (c), the return address is at [%esp]/[%rsp] and
152 * the frame pointer doesn't need to be changed when going up one
153 * level in the stack.
155 * For case (a), we check if the PC lies in low-level trap handling
156 * code, and if so we terminate our trace.
160 pmc_save_kernel_callchain(uintptr_t *cc, int nframes, struct trapframe *tf)
164 uintptr_t fp, pc, r, sp, stackstart, stackend;
167 KASSERT(TRAPF_USERMODE(tf) == 0,("[x86,%d] not a kernel backtrace",
171 pc = PMC_TRAPFRAME_TO_PC(tf);
172 fp = PMC_TRAPFRAME_TO_FP(tf);
173 sp = PMC_TRAPFRAME_TO_KERNEL_SP(tf);
176 r = fp + sizeof(uintptr_t); /* points to return address */
181 stackstart = (uintptr_t) td->td_kstack;
182 stackend = (uintptr_t) td->td_kstack + td->td_kstack_pages * PAGE_SIZE;
184 if (PMC_IN_TRAP_HANDLER(pc) ||
185 !PMC_IN_KERNEL(pc) ||
186 !PMC_IN_KERNEL_STACK(r, stackstart, stackend) ||
187 !PMC_IN_KERNEL_STACK(sp, stackstart, stackend) ||
188 !PMC_IN_KERNEL_STACK(fp, stackstart, stackend))
191 instr = *(uint32_t *) pc;
194 * Determine whether the interrupted function was in the
195 * processing of either laying down its stack frame or taking
198 * If we haven't started laying down a stack frame, or are
199 * just about to return, then our caller's address is at
200 * *sp, and we don't have a frame to unwind.
202 if (PMC_AT_FUNCTION_PROLOGUE_PUSH_BP(instr) ||
203 PMC_AT_FUNCTION_EPILOGUE_RET(instr))
204 pc = *(uintptr_t *) sp;
205 else if (PMC_AT_FUNCTION_PROLOGUE_MOV_SP_BP(instr)) {
207 * The code was midway through laying down a frame.
208 * At this point sp[0] has a frame back pointer,
209 * and the caller's address is therefore at sp[1].
211 sp += sizeof(uintptr_t);
212 if (!PMC_IN_KERNEL_STACK(sp, stackstart, stackend))
214 pc = *(uintptr_t *) sp;
217 * Not in the function prologue or epilogue.
219 pc = *(uintptr_t *) r;
220 fp = *(uintptr_t *) fp;
223 for (n = 1; n < nframes; n++) {
226 if (PMC_IN_TRAP_HANDLER(pc))
229 r = fp + sizeof(uintptr_t);
230 if (!PMC_IN_KERNEL_STACK(fp, stackstart, stackend) ||
231 !PMC_IN_KERNEL_STACK(r, stackstart, stackend))
233 pc = *(uintptr_t *) r;
234 fp = *(uintptr_t *) fp;
241 * Machine dependent initialization for x86 class platforms.
250 /* determine the CPU kind */
251 if (cpu_vendor_id == CPU_VENDOR_AMD)
252 md = pmc_amd_initialize();
253 else if (cpu_vendor_id == CPU_VENDOR_INTEL)
254 md = pmc_intel_initialize();
258 /* disallow sampling if we do not have an LAPIC */
259 if (md != NULL && !lapic_enable_pmc())
260 for (i = 0; i < md->pmd_nclass; i++) {
261 if (i == PMC_CLASS_INDEX_SOFT)
263 md->pmd_classdep[i].pcd_caps &= ~PMC_CAP_INTERRUPT;
270 pmc_md_finalize(struct pmc_mdep *md)
274 if (cpu_vendor_id == CPU_VENDOR_AMD)
275 pmc_amd_finalize(md);
276 else if (cpu_vendor_id == CPU_VENDOR_INTEL)
277 pmc_intel_finalize(md);
279 KASSERT(0, ("[x86,%d] Unknown vendor", __LINE__));