2 * Copyright (c) 2005,2008 Joseph Koshy
3 * Copyright (c) 2007 The FreeBSD Foundation
6 * Portions of this software were developed by A. Joseph Koshy under
7 * sponsorship from the FreeBSD Foundation and Google, Inc.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
34 #include <sys/param.h>
38 #include <sys/systm.h>
40 #include <machine/cpu.h>
41 #include <machine/cputypes.h>
42 #include <machine/intr_machdep.h>
43 #include <machine/apicvar.h>
44 #include <machine/pmc_mdep.h>
45 #include <machine/md_var.h>
48 #include <vm/vm_param.h>
51 #include "hwpmc_soft.h"
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.
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
61 * a. at the beginning of a function before the stack frame is laid
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
67 * If the application is not using frame pointers, this algorithm will
68 * fail to yield an interesting call chain.
70 * TODO: figure out a way to use unwind information.
74 pmc_save_user_callchain(uintptr_t *cc, int nframes, struct trapframe *tf)
78 uintptr_t fp, oldfp, pc, r, sp;
80 KASSERT(TRAPF_USERMODE(tf), ("[x86,%d] Not a user trap frame tf=%p",
81 __LINE__, (void *) tf));
83 pc = PMC_TRAPFRAME_TO_PC(tf);
84 oldfp = fp = PMC_TRAPFRAME_TO_FP(tf);
85 sp = PMC_TRAPFRAME_TO_USER_SP(tf);
89 r = fp + sizeof(uintptr_t); /* points to return address */
91 if (!PMC_IN_USERSPACE(pc))
94 if (copyin((void *) pc, &instr, sizeof(instr)) != 0)
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)
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)
105 } else if (copyin((void *) r, &pc, sizeof(pc)) != 0 ||
106 copyin((void *) fp, &fp, sizeof(fp)) != 0)
109 for (; n < nframes;) {
110 if (pc == 0 || !PMC_IN_USERSPACE(pc))
118 r = fp + sizeof(uintptr_t); /* address of return address */
121 if (copyin((void *) r, &pc, sizeof(pc)) != 0 ||
122 copyin((void *) fp, &fp, sizeof(fp)) != 0)
130 * Walking the kernel call stack.
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
136 * b. at the beginning of a function before the stack frame is laid
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
142 * In case (d), the previous frame pointer is at [%ebp]/[%rbp] and
143 * the return address is at [%ebp+4]/[%rbp+8].
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.
149 * For case (a), we check if the PC lies in low-level trap handling
150 * code, and if so we terminate our trace.
154 pmc_save_kernel_callchain(uintptr_t *cc, int nframes, struct trapframe *tf)
158 uintptr_t fp, pc, r, sp, stackstart, stackend;
161 KASSERT(TRAPF_USERMODE(tf) == 0,("[x86,%d] not a kernel backtrace",
165 pc = PMC_TRAPFRAME_TO_PC(tf);
166 fp = PMC_TRAPFRAME_TO_FP(tf);
167 sp = PMC_TRAPFRAME_TO_KERNEL_SP(tf);
170 r = fp + sizeof(uintptr_t); /* points to return address */
175 stackstart = (uintptr_t) td->td_kstack;
176 stackend = (uintptr_t) td->td_kstack + td->td_kstack_pages * PAGE_SIZE;
178 if (PMC_IN_TRAP_HANDLER(pc) ||
179 !PMC_IN_KERNEL(pc) ||
180 !PMC_IN_KERNEL_STACK(r, stackstart, stackend) ||
181 !PMC_IN_KERNEL_STACK(sp, stackstart, stackend) ||
182 !PMC_IN_KERNEL_STACK(fp, stackstart, stackend))
185 instr = *(uint32_t *) pc;
188 * Determine whether the interrupted function was in the
189 * processing of either laying down its stack frame or taking
192 * If we haven't started laying down a stack frame, or are
193 * just about to return, then our caller's address is at
194 * *sp, and we don't have a frame to unwind.
196 if (PMC_AT_FUNCTION_PROLOGUE_PUSH_BP(instr) ||
197 PMC_AT_FUNCTION_EPILOGUE_RET(instr))
198 pc = *(uintptr_t *) sp;
199 else if (PMC_AT_FUNCTION_PROLOGUE_MOV_SP_BP(instr)) {
201 * The code was midway through laying down a frame.
202 * At this point sp[0] has a frame back pointer,
203 * and the caller's address is therefore at sp[1].
205 sp += sizeof(uintptr_t);
206 if (!PMC_IN_KERNEL_STACK(sp, stackstart, stackend))
208 pc = *(uintptr_t *) sp;
211 * Not in the function prologue or epilogue.
213 pc = *(uintptr_t *) r;
214 fp = *(uintptr_t *) fp;
217 for (n = 1; n < nframes; n++) {
220 if (PMC_IN_TRAP_HANDLER(pc))
223 r = fp + sizeof(uintptr_t);
224 if (!PMC_IN_KERNEL_STACK(fp, stackstart, stackend) ||
225 !PMC_IN_KERNEL_STACK(r, stackstart, stackend))
227 pc = *(uintptr_t *) r;
228 fp = *(uintptr_t *) fp;
235 * Machine dependent initialization for x86 class platforms.
244 /* determine the CPU kind */
245 if (cpu_vendor_id == CPU_VENDOR_AMD)
246 md = pmc_amd_initialize();
247 else if (cpu_vendor_id == CPU_VENDOR_INTEL)
248 md = pmc_intel_initialize();
252 /* disallow sampling if we do not have an LAPIC */
253 if (md != NULL && !lapic_enable_pmc())
254 for (i = 0; i < md->pmd_nclass; i++) {
255 if (i == PMC_CLASS_INDEX_SOFT)
257 md->pmd_classdep[i].pcd_caps &= ~PMC_CAP_INTERRUPT;
264 pmc_md_finalize(struct pmc_mdep *md)
268 if (cpu_vendor_id == CPU_VENDOR_AMD)
269 pmc_amd_finalize(md);
270 else if (cpu_vendor_id == CPU_VENDOR_INTEL)
271 pmc_intel_finalize(md);
273 KASSERT(0, ("[x86,%d] Unknown vendor", __LINE__));