xref: /freebsd/sys/cddl/dev/dtrace/aarch64/dtrace_subr.c (revision 734e82fe33aa764367791a7d603b383996c6b40b)
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 #include <sys/param.h>
29 #include <sys/systm.h>
30 #include <sys/kernel.h>
31 #include <sys/malloc.h>
32 #include <sys/kmem.h>
33 #include <sys/proc.h>
34 #include <sys/smp.h>
35 #include <sys/dtrace_impl.h>
36 #include <sys/dtrace_bsd.h>
37 #include <cddl/dev/dtrace/dtrace_cddl.h>
38 #include <machine/armreg.h>
39 #include <machine/clock.h>
40 #include <machine/frame.h>
41 #include <machine/trap.h>
42 #include <machine/vmparam.h>
43 #include <vm/pmap.h>
44 
45 extern dtrace_id_t	dtrace_probeid_error;
46 extern int (*dtrace_invop_jump_addr)(struct trapframe *);
47 extern void dtrace_getnanotime(struct timespec *tsp);
48 extern void dtrace_getnanouptime(struct timespec *tsp);
49 
50 int dtrace_invop(uintptr_t, struct trapframe *, uintptr_t);
51 void dtrace_invop_init(void);
52 void dtrace_invop_uninit(void);
53 
54 typedef struct dtrace_invop_hdlr {
55 	int (*dtih_func)(uintptr_t, struct trapframe *, uintptr_t);
56 	struct dtrace_invop_hdlr *dtih_next;
57 } dtrace_invop_hdlr_t;
58 
59 dtrace_invop_hdlr_t *dtrace_invop_hdlr;
60 
61 int
62 dtrace_invop(uintptr_t addr, struct trapframe *frame, uintptr_t eax)
63 {
64 	struct thread *td;
65 	dtrace_invop_hdlr_t *hdlr;
66 	int rval;
67 
68 	rval = 0;
69 	td = curthread;
70 	td->t_dtrace_trapframe = frame;
71 	for (hdlr = dtrace_invop_hdlr; hdlr != NULL; hdlr = hdlr->dtih_next)
72 		if ((rval = hdlr->dtih_func(addr, frame, eax)) != 0)
73 			break;
74 	td->t_dtrace_trapframe = NULL;
75 	return (rval);
76 }
77 
78 void
79 dtrace_invop_add(int (*func)(uintptr_t, struct trapframe *, uintptr_t))
80 {
81 	dtrace_invop_hdlr_t *hdlr;
82 
83 	hdlr = kmem_alloc(sizeof (dtrace_invop_hdlr_t), KM_SLEEP);
84 	hdlr->dtih_func = func;
85 	hdlr->dtih_next = dtrace_invop_hdlr;
86 	dtrace_invop_hdlr = hdlr;
87 }
88 
89 void
90 dtrace_invop_remove(int (*func)(uintptr_t, struct trapframe *, uintptr_t))
91 {
92 	dtrace_invop_hdlr_t *hdlr, *prev;
93 
94 	hdlr = dtrace_invop_hdlr;
95 	prev = NULL;
96 
97 	for (;;) {
98 		if (hdlr == NULL)
99 			panic("attempt to remove non-existent invop handler");
100 
101 		if (hdlr->dtih_func == func)
102 			break;
103 
104 		prev = hdlr;
105 		hdlr = hdlr->dtih_next;
106 	}
107 
108 	if (prev == NULL) {
109 		ASSERT(dtrace_invop_hdlr == hdlr);
110 		dtrace_invop_hdlr = hdlr->dtih_next;
111 	} else {
112 		ASSERT(dtrace_invop_hdlr != hdlr);
113 		prev->dtih_next = hdlr->dtih_next;
114 	}
115 
116 	kmem_free(hdlr, 0);
117 }
118 
119 /*ARGSUSED*/
120 void
121 dtrace_toxic_ranges(void (*func)(uintptr_t base, uintptr_t limit))
122 {
123 
124 	(*func)(0, (uintptr_t)VM_MIN_KERNEL_ADDRESS);
125 }
126 
127 void
128 dtrace_xcall(processorid_t cpu, dtrace_xcall_t func, void *arg)
129 {
130 	cpuset_t cpus;
131 
132 	if (cpu == DTRACE_CPUALL)
133 		cpus = all_cpus;
134 	else
135 		CPU_SETOF(cpu, &cpus);
136 
137 	smp_rendezvous_cpus(cpus, smp_no_rendezvous_barrier, func,
138 	    smp_no_rendezvous_barrier, arg);
139 }
140 
141 static void
142 dtrace_sync_func(void)
143 {
144 
145 }
146 
147 void
148 dtrace_sync(void)
149 {
150 
151 	dtrace_xcall(DTRACE_CPUALL, (dtrace_xcall_t)dtrace_sync_func, NULL);
152 }
153 
154 /*
155  * DTrace needs a high resolution time function which can be called from a
156  * probe context and guaranteed not to have instrumented with probes itself.
157  *
158  * Returns nanoseconds since some arbitrary point in time (likely SoC reset?).
159  */
160 uint64_t
161 dtrace_gethrtime(void)
162 {
163 	uint64_t count, freq;
164 
165 	count = READ_SPECIALREG(cntvct_el0);
166 	freq = READ_SPECIALREG(cntfrq_el0);
167 	return ((1000000000UL * count) / freq);
168 }
169 
170 /*
171  * Return a much lower resolution wallclock time based on the system clock
172  * updated by the timer.  If needed, we could add a version interpolated from
173  * the system clock as is the case with dtrace_gethrtime().
174  */
175 uint64_t
176 dtrace_gethrestime(void)
177 {
178 	struct timespec current_time;
179 
180 	dtrace_getnanotime(&current_time);
181 
182 	return (current_time.tv_sec * 1000000000UL + current_time.tv_nsec);
183 }
184 
185 /* Function to handle DTrace traps during probes. See arm64/arm64/trap.c */
186 int
187 dtrace_trap(struct trapframe *frame, u_int type)
188 {
189 	/*
190 	 * A trap can occur while DTrace executes a probe. Before
191 	 * executing the probe, DTrace blocks re-scheduling and sets
192 	 * a flag in its per-cpu flags to indicate that it doesn't
193 	 * want to fault. On returning from the probe, the no-fault
194 	 * flag is cleared and finally re-scheduling is enabled.
195 	 *
196 	 * Check if DTrace has enabled 'no-fault' mode:
197 	 *
198 	 */
199 
200 	if ((cpu_core[curcpu].cpuc_dtrace_flags & CPU_DTRACE_NOFAULT) != 0) {
201 		/*
202 		 * There are only a couple of trap types that are expected.
203 		 * All the rest will be handled in the usual way.
204 		 */
205 		switch (type) {
206 		case EXCP_DATA_ABORT:
207 			/* Flag a bad address. */
208 			cpu_core[curcpu].cpuc_dtrace_flags |= CPU_DTRACE_BADADDR;
209 			cpu_core[curcpu].cpuc_dtrace_illval = frame->tf_far;
210 
211 			/*
212 			 * Offset the instruction pointer to the instruction
213 			 * following the one causing the fault.
214 			 */
215 			frame->tf_elr += 4;
216 			return (1);
217 		default:
218 			/* Handle all other traps in the usual way. */
219 			break;
220 		}
221 	}
222 
223 	/* Handle the trap in the usual way. */
224 	return (0);
225 }
226 
227 void
228 dtrace_probe_error(dtrace_state_t *state, dtrace_epid_t epid, int which,
229     int fault, int fltoffs, uintptr_t illval)
230 {
231 
232 	dtrace_probe(dtrace_probeid_error, (uint64_t)(uintptr_t)state,
233 	    (uintptr_t)epid,
234 	    (uintptr_t)which, (uintptr_t)fault, (uintptr_t)fltoffs);
235 }
236 
237 static void
238 dtrace_load64(uint64_t *addr, struct trapframe *frame, u_int reg)
239 {
240 
241 	KASSERT(reg <= 31, ("dtrace_load64: Invalid register %u", reg));
242 	if (reg < nitems(frame->tf_x))
243 		frame->tf_x[reg] = *addr;
244 	else if (reg == 30) /* lr */
245 		frame->tf_lr = *addr;
246 	/* Nothing to do for load to xzr */
247 }
248 
249 static void
250 dtrace_store64(uint64_t *addr, struct trapframe *frame, u_int reg)
251 {
252 
253 	KASSERT(reg <= 31, ("dtrace_store64: Invalid register %u", reg));
254 	if (reg < nitems(frame->tf_x))
255 		*addr = frame->tf_x[reg];
256 	else if (reg == 30) /* lr */
257 		*addr = frame->tf_lr;
258 	else if (reg == 31) /* xzr */
259 		*addr = 0;
260 }
261 
262 static int
263 dtrace_invop_start(struct trapframe *frame)
264 {
265 	int data, invop, reg, update_sp;
266 	register_t arg1, arg2;
267 	register_t *sp;
268 	int offs;
269 	int tmp;
270 	int i;
271 
272 	invop = dtrace_invop(frame->tf_elr, frame, frame->tf_x[0]);
273 
274 	tmp = (invop & LDP_STP_MASK);
275 	if (tmp == STP_64 || tmp == LDP_64) {
276 		sp = (register_t *)frame->tf_sp;
277 		data = invop;
278 		arg1 = (data >> ARG1_SHIFT) & ARG1_MASK;
279 		arg2 = (data >> ARG2_SHIFT) & ARG2_MASK;
280 
281 		offs = (data >> OFFSET_SHIFT) & OFFSET_MASK;
282 
283 		switch (tmp) {
284 		case STP_64:
285 			if (offs >> (OFFSET_SIZE - 1))
286 				sp -= (~offs & OFFSET_MASK) + 1;
287 			else
288 				sp += (offs);
289 			dtrace_store64(sp + 0, frame, arg1);
290 			dtrace_store64(sp + 1, frame, arg2);
291 			break;
292 		case LDP_64:
293 			dtrace_load64(sp + 0, frame, arg1);
294 			dtrace_load64(sp + 1, frame, arg2);
295 			if (offs >> (OFFSET_SIZE - 1))
296 				sp -= (~offs & OFFSET_MASK) + 1;
297 			else
298 				sp += (offs);
299 			break;
300 		default:
301 			break;
302 		}
303 
304 		/* Update the stack pointer and program counter to continue */
305 		frame->tf_sp = (register_t)sp;
306 		frame->tf_elr += INSN_SIZE;
307 		return (0);
308 	}
309 
310 	if ((invop & SUB_MASK) == SUB_INSTR) {
311 		frame->tf_sp -= (invop >> SUB_IMM_SHIFT) & SUB_IMM_MASK;
312 		frame->tf_elr += INSN_SIZE;
313 		return (0);
314 	}
315 
316 	if (invop == NOP_INSTR) {
317 		frame->tf_elr += INSN_SIZE;
318 		return (0);
319 	}
320 
321 	if ((invop & B_MASK) == B_INSTR) {
322 		data = (invop & B_DATA_MASK);
323 		/* The data is the number of 4-byte words to change the pc */
324 		data *= 4;
325 		frame->tf_elr += data;
326 		return (0);
327 	}
328 
329 	if (invop == RET_INSTR) {
330 		frame->tf_elr = frame->tf_lr;
331 		return (0);
332 	}
333 
334 	return (-1);
335 }
336 
337 void
338 dtrace_invop_init(void)
339 {
340 
341 	dtrace_invop_jump_addr = dtrace_invop_start;
342 }
343 
344 void
345 dtrace_invop_uninit(void)
346 {
347 
348 	dtrace_invop_jump_addr = 0;
349 }
350