1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 *
22 */
23 /*
24 * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
25 * Use is subject to license terms.
26 */
27
28 /*
29 * Copyright (c) 2011, Joyent, Inc. All rights reserved.
30 */
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/kernel.h>
35 #include <sys/malloc.h>
36 #include <sys/msan.h>
37 #include <sys/proc.h>
38 #include <sys/smp.h>
39 #include <sys/dtrace_impl.h>
40 #include <sys/dtrace_bsd.h>
41 #include <cddl/dev/dtrace/dtrace_cddl.h>
42 #include <machine/clock.h>
43 #include <machine/cpufunc.h>
44 #include <machine/frame.h>
45 #include <machine/md_var.h>
46 #include <machine/psl.h>
47 #include <machine/trap.h>
48 #include <vm/pmap.h>
49
50 extern void dtrace_getnanotime(struct timespec *tsp);
51 extern int (*dtrace_invop_jump_addr)(struct trapframe *);
52
53 int dtrace_invop(uintptr_t, struct trapframe *, void **);
54 int dtrace_invop_start(struct trapframe *frame);
55 void dtrace_invop_init(void);
56 void dtrace_invop_uninit(void);
57
58 typedef struct dtrace_invop_hdlr {
59 int (*dtih_func)(uintptr_t, struct trapframe *, uintptr_t);
60 struct dtrace_invop_hdlr *dtih_next;
61 } dtrace_invop_hdlr_t;
62
63 dtrace_invop_hdlr_t *dtrace_invop_hdlr;
64
65 int
dtrace_invop(uintptr_t addr,struct trapframe * frame,void ** scratch)66 dtrace_invop(uintptr_t addr, struct trapframe *frame, void **scratch)
67 {
68 struct thread *td;
69 dtrace_invop_hdlr_t *hdlr;
70 int rval;
71
72 kmsan_mark(frame, sizeof(*frame), KMSAN_STATE_INITED);
73
74 td = curthread;
75 td->t_dtrace_trapframe = frame;
76 rval = 0;
77 for (hdlr = dtrace_invop_hdlr; hdlr != NULL; hdlr = hdlr->dtih_next) {
78 rval = hdlr->dtih_func(addr, frame, (uintptr_t)scratch);
79 if (rval != 0)
80 break;
81 }
82 td->t_dtrace_trapframe = NULL;
83 return (rval);
84 }
85
86 void
dtrace_invop_add(int (* func)(uintptr_t,struct trapframe *,uintptr_t))87 dtrace_invop_add(int (*func)(uintptr_t, struct trapframe *, uintptr_t))
88 {
89 dtrace_invop_hdlr_t *hdlr;
90
91 hdlr = kmem_alloc(sizeof (dtrace_invop_hdlr_t), KM_SLEEP);
92 hdlr->dtih_func = func;
93 hdlr->dtih_next = dtrace_invop_hdlr;
94 dtrace_invop_hdlr = hdlr;
95 }
96
97 void
dtrace_invop_remove(int (* func)(uintptr_t,struct trapframe *,uintptr_t))98 dtrace_invop_remove(int (*func)(uintptr_t, struct trapframe *, uintptr_t))
99 {
100 dtrace_invop_hdlr_t *hdlr = dtrace_invop_hdlr, *prev = NULL;
101
102 for (;;) {
103 if (hdlr == NULL)
104 panic("attempt to remove non-existent invop handler");
105
106 if (hdlr->dtih_func == func)
107 break;
108
109 prev = hdlr;
110 hdlr = hdlr->dtih_next;
111 }
112
113 if (prev == NULL) {
114 ASSERT(dtrace_invop_hdlr == hdlr);
115 dtrace_invop_hdlr = hdlr->dtih_next;
116 } else {
117 ASSERT(dtrace_invop_hdlr != hdlr);
118 prev->dtih_next = hdlr->dtih_next;
119 }
120
121 kmem_free(hdlr, 0);
122 }
123
124 void
dtrace_invop_init(void)125 dtrace_invop_init(void)
126 {
127
128 dtrace_invop_jump_addr = dtrace_invop_start;
129 }
130
131 void
dtrace_invop_uninit(void)132 dtrace_invop_uninit(void)
133 {
134
135 dtrace_invop_jump_addr = NULL;
136 }
137
138 /*ARGSUSED*/
139 void
dtrace_toxic_ranges(void (* func)(uintptr_t base,uintptr_t limit))140 dtrace_toxic_ranges(void (*func)(uintptr_t base, uintptr_t limit))
141 {
142 (*func)(0, la57 ? (uintptr_t)addr_P5Tmap : (uintptr_t)addr_P4Tmap);
143 }
144
145 #ifdef notyet
146 void
dtrace_safe_synchronous_signal(void)147 dtrace_safe_synchronous_signal(void)
148 {
149 kthread_t *t = curthread;
150 struct regs *rp = lwptoregs(ttolwp(t));
151 size_t isz = t->t_dtrace_npc - t->t_dtrace_pc;
152
153 ASSERT(t->t_dtrace_on);
154
155 /*
156 * If we're not in the range of scratch addresses, we're not actually
157 * tracing user instructions so turn off the flags. If the instruction
158 * we copied out caused a synchonous trap, reset the pc back to its
159 * original value and turn off the flags.
160 */
161 if (rp->r_pc < t->t_dtrace_scrpc ||
162 rp->r_pc > t->t_dtrace_astpc + isz) {
163 t->t_dtrace_ft = 0;
164 } else if (rp->r_pc == t->t_dtrace_scrpc ||
165 rp->r_pc == t->t_dtrace_astpc) {
166 rp->r_pc = t->t_dtrace_pc;
167 t->t_dtrace_ft = 0;
168 }
169 }
170
171 int
dtrace_safe_defer_signal(void)172 dtrace_safe_defer_signal(void)
173 {
174 kthread_t *t = curthread;
175 struct regs *rp = lwptoregs(ttolwp(t));
176 size_t isz = t->t_dtrace_npc - t->t_dtrace_pc;
177
178 ASSERT(t->t_dtrace_on);
179
180 /*
181 * If we're not in the range of scratch addresses, we're not actually
182 * tracing user instructions so turn off the flags.
183 */
184 if (rp->r_pc < t->t_dtrace_scrpc ||
185 rp->r_pc > t->t_dtrace_astpc + isz) {
186 t->t_dtrace_ft = 0;
187 return (0);
188 }
189
190 /*
191 * If we have executed the original instruction, but we have performed
192 * neither the jmp back to t->t_dtrace_npc nor the clean up of any
193 * registers used to emulate %rip-relative instructions in 64-bit mode,
194 * we'll save ourselves some effort by doing that here and taking the
195 * signal right away. We detect this condition by seeing if the program
196 * counter is the range [scrpc + isz, astpc).
197 */
198 if (rp->r_pc >= t->t_dtrace_scrpc + isz &&
199 rp->r_pc < t->t_dtrace_astpc) {
200 #ifdef __amd64
201 /*
202 * If there is a scratch register and we're on the
203 * instruction immediately after the modified instruction,
204 * restore the value of that scratch register.
205 */
206 if (t->t_dtrace_reg != 0 &&
207 rp->r_pc == t->t_dtrace_scrpc + isz) {
208 switch (t->t_dtrace_reg) {
209 case REG_RAX:
210 rp->r_rax = t->t_dtrace_regv;
211 break;
212 case REG_RCX:
213 rp->r_rcx = t->t_dtrace_regv;
214 break;
215 case REG_R8:
216 rp->r_r8 = t->t_dtrace_regv;
217 break;
218 case REG_R9:
219 rp->r_r9 = t->t_dtrace_regv;
220 break;
221 }
222 }
223 #endif
224 rp->r_pc = t->t_dtrace_npc;
225 t->t_dtrace_ft = 0;
226 return (0);
227 }
228
229 /*
230 * Otherwise, make sure we'll return to the kernel after executing
231 * the copied out instruction and defer the signal.
232 */
233 if (!t->t_dtrace_step) {
234 ASSERT(rp->r_pc < t->t_dtrace_astpc);
235 rp->r_pc += t->t_dtrace_astpc - t->t_dtrace_scrpc;
236 t->t_dtrace_step = 1;
237 }
238
239 t->t_dtrace_ast = 1;
240
241 return (1);
242 }
243 #endif
244
245 static int64_t tgt_cpu_tsc;
246 static int64_t hst_cpu_tsc;
247 static int64_t tsc_skew[MAXCPU];
248 static uint64_t nsec_scale;
249
250 /* See below for the explanation of this macro. */
251 #define SCALE_SHIFT 28
252
253 static void
dtrace_gethrtime_init_cpu(void * arg)254 dtrace_gethrtime_init_cpu(void *arg)
255 {
256 uintptr_t cpu = (uintptr_t) arg;
257
258 if (cpu == curcpu)
259 tgt_cpu_tsc = rdtsc();
260 else
261 hst_cpu_tsc = rdtsc();
262 }
263
264 static void
dtrace_gethrtime_init(void * arg)265 dtrace_gethrtime_init(void *arg)
266 {
267 struct pcpu *pc;
268 uint64_t tsc_f;
269 cpuset_t map;
270 int i;
271
272 /*
273 * Get TSC frequency known at this moment.
274 * This should be constant if TSC is invariant.
275 * Otherwise tick->time conversion will be inaccurate, but
276 * will preserve monotonic property of TSC.
277 */
278 tsc_f = atomic_load_acq_64(&tsc_freq);
279
280 /*
281 * The following line checks that nsec_scale calculated below
282 * doesn't overflow 32-bit unsigned integer, so that it can multiply
283 * another 32-bit integer without overflowing 64-bit.
284 * Thus minimum supported TSC frequency is 62.5MHz.
285 */
286 KASSERT(tsc_f > (NANOSEC >> (32 - SCALE_SHIFT)),
287 ("TSC frequency is too low"));
288
289 /*
290 * We scale up NANOSEC/tsc_f ratio to preserve as much precision
291 * as possible.
292 * 2^28 factor was chosen quite arbitrarily from practical
293 * considerations:
294 * - it supports TSC frequencies as low as 62.5MHz (see above);
295 * - it provides quite good precision (e < 0.01%) up to THz
296 * (terahertz) values;
297 */
298 nsec_scale = ((uint64_t)NANOSEC << SCALE_SHIFT) / tsc_f;
299
300 if (vm_guest != VM_GUEST_NO)
301 return;
302
303 /* The current CPU is the reference one. */
304 sched_pin();
305 tsc_skew[curcpu] = 0;
306 CPU_FOREACH(i) {
307 if (i == curcpu)
308 continue;
309
310 pc = pcpu_find(i);
311 CPU_SETOF(PCPU_GET(cpuid), &map);
312 CPU_SET(pc->pc_cpuid, &map);
313
314 smp_rendezvous_cpus(map, NULL,
315 dtrace_gethrtime_init_cpu,
316 smp_no_rendezvous_barrier, (void *)(uintptr_t) i);
317
318 tsc_skew[i] = tgt_cpu_tsc - hst_cpu_tsc;
319 }
320 sched_unpin();
321 }
322 SYSINIT(dtrace_gethrtime_init, SI_SUB_DTRACE, SI_ORDER_ANY,
323 dtrace_gethrtime_init, NULL);
324
325 /*
326 * DTrace needs a high resolution time function which can
327 * be called from a probe context and guaranteed not to have
328 * instrumented with probes itself.
329 *
330 * Returns nanoseconds since boot.
331 */
332 uint64_t
dtrace_gethrtime(void)333 dtrace_gethrtime(void)
334 {
335 uint64_t tsc;
336 uint32_t lo, hi;
337 register_t rflags;
338
339 /*
340 * We split TSC value into lower and higher 32-bit halves and separately
341 * scale them with nsec_scale, then we scale them down by 2^28
342 * (see nsec_scale calculations) taking into account 32-bit shift of
343 * the higher half and finally add.
344 */
345 rflags = intr_disable();
346 tsc = rdtsc() - tsc_skew[curcpu];
347 intr_restore(rflags);
348
349 lo = tsc;
350 hi = tsc >> 32;
351 return (((lo * nsec_scale) >> SCALE_SHIFT) +
352 ((hi * nsec_scale) << (32 - SCALE_SHIFT)));
353 }
354
355 uint64_t
dtrace_gethrestime(void)356 dtrace_gethrestime(void)
357 {
358 struct timespec current_time;
359
360 dtrace_getnanotime(¤t_time);
361
362 return (current_time.tv_sec * 1000000000ULL + current_time.tv_nsec);
363 }
364
365 /* Function to handle DTrace traps during probes. See amd64/amd64/trap.c. */
366 int
dtrace_trap(struct trapframe * frame,u_int type)367 dtrace_trap(struct trapframe *frame, u_int type)
368 {
369 uint16_t nofault;
370
371 /*
372 * A trap can occur while DTrace executes a probe. Before
373 * executing the probe, DTrace blocks re-scheduling and sets
374 * a flag in its per-cpu flags to indicate that it doesn't
375 * want to fault. On returning from the probe, the no-fault
376 * flag is cleared and finally re-scheduling is enabled.
377 *
378 * Check if DTrace has enabled 'no-fault' mode:
379 */
380 sched_pin();
381 nofault = cpu_core[curcpu].cpuc_dtrace_flags & CPU_DTRACE_NOFAULT;
382 sched_unpin();
383 if (nofault) {
384 KASSERT((read_rflags() & PSL_I) == 0, ("interrupts enabled"));
385
386 /*
387 * There are only a couple of trap types that are expected.
388 * All the rest will be handled in the usual way.
389 */
390 switch (type) {
391 /* General protection fault. */
392 case T_PROTFLT:
393 /* Flag an illegal operation. */
394 cpu_core[curcpu].cpuc_dtrace_flags |= CPU_DTRACE_ILLOP;
395
396 /*
397 * Offset the instruction pointer to the instruction
398 * following the one causing the fault.
399 */
400 frame->tf_rip += dtrace_instr_size((uint8_t *) frame->tf_rip);
401 return (1);
402 /* Page fault. */
403 case T_PAGEFLT:
404 /* Flag a bad address. */
405 cpu_core[curcpu].cpuc_dtrace_flags |= CPU_DTRACE_BADADDR;
406 cpu_core[curcpu].cpuc_dtrace_illval = frame->tf_addr;
407
408 /*
409 * Offset the instruction pointer to the instruction
410 * following the one causing the fault.
411 */
412 frame->tf_rip += dtrace_instr_size((uint8_t *) frame->tf_rip);
413 return (1);
414 default:
415 /* Handle all other traps in the usual way. */
416 break;
417 }
418 }
419
420 /* Handle the trap in the usual way. */
421 return (0);
422 }
423