xref: /freebsd/sys/cddl/dev/dtrace/arm/dtrace_subr.c (revision d5b0e70f7e04d971691517ce1304d86a1e367e2e)
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  * $FreeBSD$
23  *
24  */
25 /*
26  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
27  * Use is subject to license terms.
28  */
29 
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/kernel.h>
33 #include <sys/malloc.h>
34 #include <sys/kmem.h>
35 #include <sys/proc.h>
36 #include <sys/smp.h>
37 #include <sys/dtrace_impl.h>
38 #include <sys/dtrace_bsd.h>
39 #include <cddl/dev/dtrace/dtrace_cddl.h>
40 #include <machine/armreg.h>
41 #include <machine/clock.h>
42 #include <machine/frame.h>
43 #include <machine/trap.h>
44 #include <vm/pmap.h>
45 
46 #define	DELAYBRANCH(x)	((int)(x) < 0)
47 
48 #define	BIT_PC		15
49 #define	BIT_LR		14
50 #define	BIT_SP		13
51 
52 extern dtrace_id_t	dtrace_probeid_error;
53 extern int (*dtrace_invop_jump_addr)(struct trapframe *);
54 extern void dtrace_getnanotime(struct timespec *tsp);
55 extern void dtrace_getnanouptime(struct timespec *tsp);
56 
57 int dtrace_invop(uintptr_t, struct trapframe *, uintptr_t);
58 void dtrace_invop_init(void);
59 void dtrace_invop_uninit(void);
60 
61 typedef struct dtrace_invop_hdlr {
62 	int (*dtih_func)(uintptr_t, struct trapframe *, uintptr_t);
63 	struct dtrace_invop_hdlr *dtih_next;
64 } dtrace_invop_hdlr_t;
65 
66 dtrace_invop_hdlr_t *dtrace_invop_hdlr;
67 
68 int
69 dtrace_invop(uintptr_t addr, struct trapframe *frame, uintptr_t eax)
70 {
71 	struct thread *td;
72 	dtrace_invop_hdlr_t *hdlr;
73 	int rval;
74 
75 	rval = 0;
76 	td = curthread;
77 	td->t_dtrace_trapframe = frame;
78 	for (hdlr = dtrace_invop_hdlr; hdlr != NULL; hdlr = hdlr->dtih_next)
79 		if ((rval = hdlr->dtih_func(addr, frame, eax)) != 0)
80 			break;
81 	td->t_dtrace_trapframe = NULL;
82 	return (rval);
83 }
84 
85 
86 void
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
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 
125 /*ARGSUSED*/
126 void
127 dtrace_toxic_ranges(void (*func)(uintptr_t base, uintptr_t limit))
128 {
129 
130 	/*
131 	 * There are no ranges to exclude that are common to all 32-bit arm
132 	 * platforms.  This function only needs to exclude ranges "... in
133 	 * which it is impossible to recover from such a load after it has been
134 	 * attempted." -- i.e., accessing within the range causes some sort
135 	 * fault in the system which is not handled by the normal arm
136 	 * exception-handling mechanisms.  If systems exist where that is the
137 	 * case, a method to handle this functionality would have to be added to
138 	 * the platform_if interface so that those systems could provide their
139 	 * specific toxic range(s).
140 	 */
141 }
142 
143 void
144 dtrace_xcall(processorid_t cpu, dtrace_xcall_t func, void *arg)
145 {
146 	cpuset_t cpus;
147 
148 	if (cpu == DTRACE_CPUALL)
149 		cpus = all_cpus;
150 	else
151 		CPU_SETOF(cpu, &cpus);
152 
153 	smp_rendezvous_cpus(cpus, smp_no_rendezvous_barrier, func,
154 	    smp_no_rendezvous_barrier, arg);
155 }
156 
157 static void
158 dtrace_sync_func(void)
159 {
160 }
161 
162 void
163 dtrace_sync(void)
164 {
165 	dtrace_xcall(DTRACE_CPUALL, (dtrace_xcall_t)dtrace_sync_func, NULL);
166 }
167 
168 /*
169  * DTrace needs a high resolution time function which can
170  * be called from a probe context and guaranteed not to have
171  * instrumented with probes itself.
172  *
173  * Returns nanoseconds since boot.
174  */
175 uint64_t
176 dtrace_gethrtime(void)
177 {
178 	struct	timespec curtime;
179 
180 	dtrace_getnanouptime(&curtime);
181 
182 	return (curtime.tv_sec * 1000000000UL + curtime.tv_nsec);
183 
184 }
185 
186 uint64_t
187 dtrace_gethrestime(void)
188 {
189 	struct timespec current_time;
190 
191 	dtrace_getnanotime(&current_time);
192 
193 	return (current_time.tv_sec * 1000000000UL + current_time.tv_nsec);
194 }
195 
196 /* Function to handle DTrace traps during probes. See amd64/amd64/trap.c */
197 int
198 dtrace_trap(struct trapframe *frame, u_int type)
199 {
200 	/*
201 	 * A trap can occur while DTrace executes a probe. Before
202 	 * executing the probe, DTrace blocks re-scheduling and sets
203 	 * a flag in its per-cpu flags to indicate that it doesn't
204 	 * want to fault. On returning from the probe, the no-fault
205 	 * flag is cleared and finally re-scheduling is enabled.
206 	 *
207 	 * Check if DTrace has enabled 'no-fault' mode:
208 	 *
209 	 */
210 	if ((cpu_core[curcpu].cpuc_dtrace_flags & CPU_DTRACE_NOFAULT) != 0) {
211 		/*
212 		 * There are only a couple of trap types that are expected.
213 		 * All the rest will be handled in the usual way.
214 		 */
215 		switch (type) {
216 		/* Page fault. */
217 		case FAULT_ALIGN:
218 			/* Flag a bad address. */
219 			cpu_core[curcpu].cpuc_dtrace_flags |= CPU_DTRACE_BADADDR;
220 			cpu_core[curcpu].cpuc_dtrace_illval = 0;
221 
222 			/*
223 			 * Offset the instruction pointer to the instruction
224 			 * following the one causing the fault.
225 			 */
226 			frame->tf_pc += sizeof(int);
227 			return (1);
228 		default:
229 			/* Handle all other traps in the usual way. */
230 			break;
231 		}
232 	}
233 
234 	/* Handle the trap in the usual way. */
235 	return (0);
236 }
237 
238 void
239 dtrace_probe_error(dtrace_state_t *state, dtrace_epid_t epid, int which,
240     int fault, int fltoffs, uintptr_t illval)
241 {
242 
243 	dtrace_probe(dtrace_probeid_error, (uint64_t)(uintptr_t)state,
244 	    (uintptr_t)epid,
245 	    (uintptr_t)which, (uintptr_t)fault, (uintptr_t)fltoffs);
246 }
247 
248 static int
249 dtrace_invop_start(struct trapframe *frame)
250 {
251 	register_t *r0, *sp;
252 	int data, invop, reg, update_sp;
253 
254 	invop = dtrace_invop(frame->tf_pc, frame, frame->tf_r0);
255 	switch (invop & DTRACE_INVOP_MASK) {
256 	case DTRACE_INVOP_PUSHM:
257 		sp = (register_t *)frame->tf_svc_sp;
258 		r0 = &frame->tf_r0;
259 		data = DTRACE_INVOP_DATA(invop);
260 
261 		/*
262 		 * Store the pc, lr, and sp. These have their own
263 		 * entries in the struct.
264 		 */
265 		if (data & (1 << BIT_PC)) {
266 			sp--;
267 			*sp = frame->tf_pc;
268 		}
269 		if (data & (1 << BIT_LR)) {
270 			sp--;
271 			*sp = frame->tf_svc_lr;
272 		}
273 		if (data & (1 << BIT_SP)) {
274 			sp--;
275 			*sp = frame->tf_svc_sp;
276 		}
277 
278 		/* Store the general registers */
279 		for (reg = 12; reg >= 0; reg--) {
280 			if (data & (1 << reg)) {
281 				sp--;
282 				*sp = r0[reg];
283 			}
284 		}
285 
286 		/* Update the stack pointer and program counter to continue */
287 		frame->tf_svc_sp = (register_t)sp;
288 		frame->tf_pc += 4;
289 		break;
290 	case DTRACE_INVOP_POPM:
291 		sp = (register_t *)frame->tf_svc_sp;
292 		r0 = &frame->tf_r0;
293 		data = DTRACE_INVOP_DATA(invop);
294 
295 		/* Read the general registers */
296 		for (reg = 0; reg <= 12; reg++) {
297 			if (data & (1 << reg)) {
298 				r0[reg] = *sp;
299 				sp++;
300 			}
301 		}
302 
303 		/*
304 		 * Set the stack pointer. If we don't update it here we will
305 		 * need to update it at the end as the instruction would do
306 		 */
307 		update_sp = 1;
308 		if (data & (1 << BIT_SP)) {
309 			frame->tf_svc_sp = *sp;
310 			*sp++;
311 			update_sp = 0;
312 		}
313 
314 		/* Update the link register, we need to use the correct copy */
315 		if (data & (1 << BIT_LR)) {
316 			frame->tf_svc_lr = *sp;
317 			*sp++;
318 		}
319 		/*
320 		 * And the program counter. If it's not in the list skip over
321 		 * it when we return so to not hit this again.
322 		 */
323 		if (data & (1 << BIT_PC)) {
324 			frame->tf_pc = *sp;
325 			*sp++;
326 		} else
327 			frame->tf_pc += 4;
328 
329 		/* Update the stack pointer if we haven't already done so */
330 		if (update_sp)
331 			frame->tf_svc_sp = (register_t)sp;
332 		break;
333 	case DTRACE_INVOP_B:
334 		data = DTRACE_INVOP_DATA(invop) & 0x00ffffff;
335 		/* Sign extend the data */
336 		if ((data & (1 << 23)) != 0)
337 			data |= 0xff000000;
338 		/* The data is the number of 4-byte words to change the pc */
339 		data *= 4;
340 		data += 8;
341 		frame->tf_pc += data;
342 		break;
343 	default:
344 		return (-1);
345 		break;
346 	}
347 
348 	return (0);
349 }
350 
351 void dtrace_invop_init(void)
352 {
353 	dtrace_invop_jump_addr = dtrace_invop_start;
354 }
355 
356 void dtrace_invop_uninit(void)
357 {
358 	dtrace_invop_jump_addr = 0;
359 }
360