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 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/bus.h>
37 #include <sys/pmc.h>
38
39 #include <vm/vm.h>
40 #include <vm/pmap.h>
41
42 #include <machine/cpu.h>
43 #include <machine/cputypes.h>
44 #include <machine/intr_machdep.h> /* For x86/apicvar.h */
45 #include <machine/md_var.h>
46 #include <machine/pmc_mdep.h>
47 #include <machine/stack.h>
48 #include <machine/vmparam.h>
49
50 #include <x86/apicvar.h>
51
52 #include "hwpmc_soft.h"
53
54 /*
55 * Attempt to walk a user call stack using a too-simple algorithm.
56 * In the general case we need unwind information associated with
57 * the executable to be able to walk the user stack.
58 *
59 * We are handed a trap frame laid down at the time the PMC interrupt
60 * was taken. If the application is using frame pointers, the saved
61 * PC value could be:
62 * a. at the beginning of a function before the stack frame is laid
63 * down,
64 * b. just before a 'ret', after the stack frame has been taken off,
65 * c. somewhere else in the function with a valid stack frame being
66 * present,
67 *
68 * If the application is not using frame pointers, this algorithm will
69 * fail to yield an interesting call chain.
70 *
71 * TODO: figure out a way to use unwind information.
72 */
73
74 int
pmc_save_user_callchain(uintptr_t * cc,int nframes,struct trapframe * tf)75 pmc_save_user_callchain(uintptr_t *cc, int nframes, struct trapframe *tf)
76 {
77 int n;
78 uint32_t instr;
79 uintptr_t fp, oldfp, pc, r, sp;
80
81 KASSERT(TRAPF_USERMODE(tf), ("[x86,%d] Not a user trap frame tf=%p",
82 __LINE__, (void *) tf));
83
84 pc = PMC_TRAPFRAME_TO_PC(tf);
85 oldfp = fp = PMC_TRAPFRAME_TO_FP(tf);
86 sp = PMC_TRAPFRAME_TO_USER_SP(tf);
87
88 *cc++ = pc; n = 1;
89
90 r = fp + sizeof(uintptr_t); /* points to return address */
91
92 if (!PMC_IN_USERSPACE(pc))
93 return (n);
94
95 if (copyin((void *) pc, &instr, sizeof(instr)) != 0)
96 return (n);
97
98 if (PMC_AT_FUNCTION_PROLOGUE_PUSH_BP(instr) ||
99 PMC_AT_FUNCTION_EPILOGUE_RET(instr)) { /* ret */
100 if (copyin((void *) sp, &pc, sizeof(pc)) != 0)
101 return (n);
102 } else if (PMC_AT_FUNCTION_PROLOGUE_MOV_SP_BP(instr)) {
103 sp += sizeof(uintptr_t);
104 if (copyin((void *) sp, &pc, sizeof(pc)) != 0)
105 return (n);
106 } else if (copyin((void *) r, &pc, sizeof(pc)) != 0 ||
107 copyin((void *) fp, &fp, sizeof(fp)) != 0)
108 return (n);
109
110 for (; n < nframes;) {
111 if (pc == 0 || !PMC_IN_USERSPACE(pc))
112 break;
113
114 *cc++ = pc; n++;
115
116 if (fp < oldfp)
117 break;
118
119 r = fp + sizeof(uintptr_t); /* address of return address */
120 oldfp = fp;
121
122 if (copyin((void *) r, &pc, sizeof(pc)) != 0 ||
123 copyin((void *) fp, &fp, sizeof(fp)) != 0)
124 break;
125 }
126
127 return (n);
128 }
129
130 /*
131 * Walking the kernel call stack.
132 *
133 * We are handed the trap frame laid down at the time the PMC
134 * interrupt was taken. The saved PC could be:
135 * a. in the lowlevel trap handler, meaning that there isn't a C stack
136 * to traverse,
137 * b. at the beginning of a function before the stack frame is laid
138 * down,
139 * c. just before a 'ret', after the stack frame has been taken off,
140 * d. somewhere else in a function with a valid stack frame being
141 * present.
142 *
143 * In case (d), the previous frame pointer is at [%ebp]/[%rbp] and
144 * the return address is at [%ebp+4]/[%rbp+8].
145 *
146 * For cases (b) and (c), the return address is at [%esp]/[%rsp] and
147 * the frame pointer doesn't need to be changed when going up one
148 * level in the stack.
149 *
150 * For case (a), we check if the PC lies in low-level trap handling
151 * code, and if so we terminate our trace.
152 */
153
154 int __nosanitizeaddress __nosanitizememory
pmc_save_kernel_callchain(uintptr_t * cc,int nframes,struct trapframe * tf)155 pmc_save_kernel_callchain(uintptr_t *cc, int nframes, struct trapframe *tf)
156 {
157 uintptr_t fp, pc, ra, sp;
158 uint32_t instr;
159 int n;
160
161 KASSERT(TRAPF_USERMODE(tf) == 0,("[x86,%d] not a kernel backtrace",
162 __LINE__));
163
164 pc = PMC_TRAPFRAME_TO_PC(tf);
165 fp = PMC_TRAPFRAME_TO_FP(tf);
166 sp = PMC_TRAPFRAME_TO_KERNEL_SP(tf);
167
168 *cc++ = pc;
169 ra = fp + sizeof(uintptr_t); /* points to return address */
170
171 if (nframes <= 1)
172 return (1);
173
174 if (PMC_IN_TRAP_HANDLER(pc) || !PMC_IN_KERNEL(pc) ||
175 !PMC_IN_KERNEL_STACK(ra) || !PMC_IN_KERNEL_STACK(sp) ||
176 !PMC_IN_KERNEL_STACK(fp))
177 return (1);
178
179 instr = *(uint32_t *)pc;
180
181 /*
182 * Determine whether the interrupted function was in the
183 * processing of either laying down its stack frame or taking
184 * it off.
185 *
186 * If we haven't started laying down a stack frame, or are
187 * just about to return, then our caller's address is at
188 * *sp, and we don't have a frame to unwind.
189 */
190 if (PMC_AT_FUNCTION_PROLOGUE_PUSH_BP(instr) ||
191 PMC_AT_FUNCTION_EPILOGUE_RET(instr))
192 pc = *(uintptr_t *) sp;
193 else if (PMC_AT_FUNCTION_PROLOGUE_MOV_SP_BP(instr)) {
194 /*
195 * The code was midway through laying down a frame.
196 * At this point sp[0] has a frame back pointer,
197 * and the caller's address is therefore at sp[1].
198 */
199 sp += sizeof(uintptr_t);
200 if (!PMC_IN_KERNEL_STACK(sp))
201 return (1);
202 pc = *(uintptr_t *)sp;
203 } else {
204 /*
205 * Not in the function prologue or epilogue.
206 */
207 pc = *(uintptr_t *)ra;
208 fp = *(uintptr_t *)fp;
209 }
210
211 for (n = 1; n < nframes; n++) {
212 *cc++ = pc;
213
214 if (PMC_IN_TRAP_HANDLER(pc))
215 break;
216
217 ra = fp + sizeof(uintptr_t);
218 if (!PMC_IN_KERNEL_STACK(fp) || !PMC_IN_KERNEL_STACK(ra))
219 break;
220 pc = *(uintptr_t *)ra;
221 fp = *(uintptr_t *)fp;
222 }
223
224 return (n);
225 }
226
227 /*
228 * Machine dependent initialization for x86 class platforms.
229 */
230 struct pmc_mdep *
pmc_md_initialize(void)231 pmc_md_initialize(void)
232 {
233 int i;
234 struct pmc_mdep *md;
235
236 /* determine the CPU kind */
237 if (cpu_vendor_id == CPU_VENDOR_AMD ||
238 cpu_vendor_id == CPU_VENDOR_HYGON)
239 md = pmc_amd_initialize();
240 else if (cpu_vendor_id == CPU_VENDOR_INTEL)
241 md = pmc_intel_initialize();
242 else
243 return (NULL);
244
245 /* disallow sampling if we do not have an LAPIC */
246 if (md != NULL && !lapic_enable_pmc())
247 for (i = 0; i < md->pmd_nclass; i++) {
248 if (i == PMC_CLASS_INDEX_SOFT)
249 continue;
250 md->pmd_classdep[i].pcd_caps &= ~PMC_CAP_INTERRUPT;
251 }
252
253 return (md);
254 }
255
256 void
pmc_md_finalize(struct pmc_mdep * md)257 pmc_md_finalize(struct pmc_mdep *md)
258 {
259
260 lapic_disable_pmc();
261 if (cpu_vendor_id == CPU_VENDOR_AMD ||
262 cpu_vendor_id == CPU_VENDOR_HYGON)
263 pmc_amd_finalize(md);
264 else if (cpu_vendor_id == CPU_VENDOR_INTEL)
265 pmc_intel_finalize(md);
266 else
267 KASSERT(0, ("[x86,%d] Unknown vendor", __LINE__));
268 }
269