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
pmc_save_user_callchain(uintptr_t * cc,int nframes,struct trapframe * tf)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
pmc_save_kernel_callchain(uintptr_t * cc,int nframes,struct trapframe * tf)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 *
pmc_md_initialize(void)230 pmc_md_initialize(void)
231 {
232 int i;
233 struct pmc_mdep *md = NULL;
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
242 if (md == NULL)
243 return (NULL);
244
245 nmi_register_handler(md->pmd_intr);
246 /* disallow sampling if we do not have an LAPIC */
247 if (!lapic_enable_pcint())
248 for (i = 0; i < md->pmd_nclass; i++) {
249 if (i == PMC_CLASS_INDEX_SOFT)
250 continue;
251 md->pmd_classdep[i].pcd_caps &= ~PMC_CAP_INTERRUPT;
252 }
253
254 return (md);
255 }
256
257 void
pmc_md_finalize(struct pmc_mdep * md)258 pmc_md_finalize(struct pmc_mdep *md)
259 {
260 if (md != NULL) {
261 lapic_disable_pcint();
262 nmi_remove_handler(md->pmd_intr);
263 }
264 if (cpu_vendor_id == CPU_VENDOR_AMD ||
265 cpu_vendor_id == CPU_VENDOR_HYGON)
266 pmc_amd_finalize(md);
267 else if (cpu_vendor_id == CPU_VENDOR_INTEL)
268 pmc_intel_finalize(md);
269 else
270 KASSERT(0, ("[x86,%d] Unknown vendor", __LINE__));
271 }
272