xref: /freebsd/sys/cddl/dev/dtrace/arm/dtrace_subr.c (revision 2f513db72b034fd5ef7f080b11be5c711c15186a)
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/cdefs.h>
31 __FBSDID("$FreeBSD$");
32 
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/types.h>
36 #include <sys/kernel.h>
37 #include <sys/malloc.h>
38 #include <sys/kmem.h>
39 #include <sys/smp.h>
40 #include <sys/dtrace_impl.h>
41 #include <sys/dtrace_bsd.h>
42 #include <machine/armreg.h>
43 #include <machine/clock.h>
44 #include <machine/frame.h>
45 #include <machine/trap.h>
46 #include <vm/pmap.h>
47 
48 #define	DELAYBRANCH(x)	((int)(x) < 0)
49 
50 #define	BIT_PC		15
51 #define	BIT_LR		14
52 #define	BIT_SP		13
53 
54 extern dtrace_id_t	dtrace_probeid_error;
55 extern int (*dtrace_invop_jump_addr)(struct trapframe *);
56 extern void dtrace_getnanotime(struct timespec *tsp);
57 
58 int dtrace_invop(uintptr_t, struct trapframe *, uintptr_t);
59 void dtrace_invop_init(void);
60 void dtrace_invop_uninit(void);
61 
62 typedef struct dtrace_invop_hdlr {
63 	int (*dtih_func)(uintptr_t, struct trapframe *, uintptr_t);
64 	struct dtrace_invop_hdlr *dtih_next;
65 } dtrace_invop_hdlr_t;
66 
67 dtrace_invop_hdlr_t *dtrace_invop_hdlr;
68 
69 int
70 dtrace_invop(uintptr_t addr, struct trapframe *frame, uintptr_t eax)
71 {
72 	dtrace_invop_hdlr_t *hdlr;
73 	int rval;
74 
75 	for (hdlr = dtrace_invop_hdlr; hdlr != NULL; hdlr = hdlr->dtih_next)
76 		if ((rval = hdlr->dtih_func(addr, frame, eax)) != 0)
77 			return (rval);
78 
79 	return (0);
80 }
81 
82 
83 void
84 dtrace_invop_add(int (*func)(uintptr_t, struct trapframe *, uintptr_t))
85 {
86 	dtrace_invop_hdlr_t *hdlr;
87 
88 	hdlr = kmem_alloc(sizeof (dtrace_invop_hdlr_t), KM_SLEEP);
89 	hdlr->dtih_func = func;
90 	hdlr->dtih_next = dtrace_invop_hdlr;
91 	dtrace_invop_hdlr = hdlr;
92 }
93 
94 void
95 dtrace_invop_remove(int (*func)(uintptr_t, struct trapframe *, uintptr_t))
96 {
97 	dtrace_invop_hdlr_t *hdlr = dtrace_invop_hdlr, *prev = NULL;
98 
99 	for (;;) {
100 		if (hdlr == NULL)
101 			panic("attempt to remove non-existent invop handler");
102 
103 		if (hdlr->dtih_func == func)
104 			break;
105 
106 		prev = hdlr;
107 		hdlr = hdlr->dtih_next;
108 	}
109 
110 	if (prev == NULL) {
111 		ASSERT(dtrace_invop_hdlr == hdlr);
112 		dtrace_invop_hdlr = hdlr->dtih_next;
113 	} else {
114 		ASSERT(dtrace_invop_hdlr != hdlr);
115 		prev->dtih_next = hdlr->dtih_next;
116 	}
117 
118 	kmem_free(hdlr, 0);
119 }
120 
121 
122 /*ARGSUSED*/
123 void
124 dtrace_toxic_ranges(void (*func)(uintptr_t base, uintptr_t limit))
125 {
126 
127 	/*
128 	 * There are no ranges to exclude that are common to all 32-bit arm
129 	 * platforms.  This function only needs to exclude ranges "... in
130 	 * which it is impossible to recover from such a load after it has been
131 	 * attempted." -- i.e., accessing within the range causes some sort
132 	 * fault in the system which is not handled by the normal arm
133 	 * exception-handling mechanisms.  If systems exist where that is the
134 	 * case, a method to handle this functionality would have to be added to
135 	 * the platform_if interface so that those systems could provide their
136 	 * specific toxic range(s).
137 	 */
138 }
139 
140 void
141 dtrace_xcall(processorid_t cpu, dtrace_xcall_t func, void *arg)
142 {
143 	cpuset_t cpus;
144 
145 	if (cpu == DTRACE_CPUALL)
146 		cpus = all_cpus;
147 	else
148 		CPU_SETOF(cpu, &cpus);
149 
150 	smp_rendezvous_cpus(cpus, smp_no_rendezvous_barrier, func,
151 	    smp_no_rendezvous_barrier, arg);
152 }
153 
154 static void
155 dtrace_sync_func(void)
156 {
157 }
158 
159 void
160 dtrace_sync(void)
161 {
162 	dtrace_xcall(DTRACE_CPUALL, (dtrace_xcall_t)dtrace_sync_func, NULL);
163 }
164 
165 /*
166  * DTrace needs a high resolution time function which can
167  * be called from a probe context and guaranteed not to have
168  * instrumented with probes itself.
169  *
170  * Returns nanoseconds since boot.
171  */
172 uint64_t
173 dtrace_gethrtime()
174 {
175 	struct	timespec curtime;
176 
177 	nanouptime(&curtime);
178 
179 	return (curtime.tv_sec * 1000000000UL + curtime.tv_nsec);
180 
181 }
182 
183 uint64_t
184 dtrace_gethrestime(void)
185 {
186 	struct timespec current_time;
187 
188 	dtrace_getnanotime(&current_time);
189 
190 	return (current_time.tv_sec * 1000000000UL + current_time.tv_nsec);
191 }
192 
193 /* Function to handle DTrace traps during probes. See amd64/amd64/trap.c */
194 int
195 dtrace_trap(struct trapframe *frame, u_int type)
196 {
197 	/*
198 	 * A trap can occur while DTrace executes a probe. Before
199 	 * executing the probe, DTrace blocks re-scheduling and sets
200 	 * a flag in its per-cpu flags to indicate that it doesn't
201 	 * want to fault. On returning from the probe, the no-fault
202 	 * flag is cleared and finally re-scheduling is enabled.
203 	 *
204 	 * Check if DTrace has enabled 'no-fault' mode:
205 	 *
206 	 */
207 	if ((cpu_core[curcpu].cpuc_dtrace_flags & CPU_DTRACE_NOFAULT) != 0) {
208 		/*
209 		 * There are only a couple of trap types that are expected.
210 		 * All the rest will be handled in the usual way.
211 		 */
212 		switch (type) {
213 		/* Page fault. */
214 		case FAULT_ALIGN:
215 			/* Flag a bad address. */
216 			cpu_core[curcpu].cpuc_dtrace_flags |= CPU_DTRACE_BADADDR;
217 			cpu_core[curcpu].cpuc_dtrace_illval = 0;
218 
219 			/*
220 			 * Offset the instruction pointer to the instruction
221 			 * following the one causing the fault.
222 			 */
223 			frame->tf_pc += sizeof(int);
224 			return (1);
225 		default:
226 			/* Handle all other traps in the usual way. */
227 			break;
228 		}
229 	}
230 
231 	/* Handle the trap in the usual way. */
232 	return (0);
233 }
234 
235 void
236 dtrace_probe_error(dtrace_state_t *state, dtrace_epid_t epid, int which,
237     int fault, int fltoffs, uintptr_t illval)
238 {
239 
240 	dtrace_probe(dtrace_probeid_error, (uint64_t)(uintptr_t)state,
241 	    (uintptr_t)epid,
242 	    (uintptr_t)which, (uintptr_t)fault, (uintptr_t)fltoffs);
243 }
244 
245 static int
246 dtrace_invop_start(struct trapframe *frame)
247 {
248 	register_t *r0, *sp;
249 	int data, invop, reg, update_sp;
250 
251 	invop = dtrace_invop(frame->tf_pc, frame, frame->tf_pc);
252 	switch (invop & DTRACE_INVOP_MASK) {
253 	case DTRACE_INVOP_PUSHM:
254 		sp = (register_t *)frame->tf_svc_sp;
255 		r0 = &frame->tf_r0;
256 		data = DTRACE_INVOP_DATA(invop);
257 
258 		/*
259 		 * Store the pc, lr, and sp. These have their own
260 		 * entries in the struct.
261 		 */
262 		if (data & (1 << BIT_PC)) {
263 			sp--;
264 			*sp = frame->tf_pc;
265 		}
266 		if (data & (1 << BIT_LR)) {
267 			sp--;
268 			*sp = frame->tf_svc_lr;
269 		}
270 		if (data & (1 << BIT_SP)) {
271 			sp--;
272 			*sp = frame->tf_svc_sp;
273 		}
274 
275 		/* Store the general registers */
276 		for (reg = 12; reg >= 0; reg--) {
277 			if (data & (1 << reg)) {
278 				sp--;
279 				*sp = r0[reg];
280 			}
281 		}
282 
283 		/* Update the stack pointer and program counter to continue */
284 		frame->tf_svc_sp = (register_t)sp;
285 		frame->tf_pc += 4;
286 		break;
287 	case DTRACE_INVOP_POPM:
288 		sp = (register_t *)frame->tf_svc_sp;
289 		r0 = &frame->tf_r0;
290 		data = DTRACE_INVOP_DATA(invop);
291 
292 		/* Read the general registers */
293 		for (reg = 0; reg <= 12; reg++) {
294 			if (data & (1 << reg)) {
295 				r0[reg] = *sp;
296 				sp++;
297 			}
298 		}
299 
300 		/*
301 		 * Set the stack pointer. If we don't update it here we will
302 		 * need to update it at the end as the instruction would do
303 		 */
304 		update_sp = 1;
305 		if (data & (1 << BIT_SP)) {
306 			frame->tf_svc_sp = *sp;
307 			*sp++;
308 			update_sp = 0;
309 		}
310 
311 		/* Update the link register, we need to use the correct copy */
312 		if (data & (1 << BIT_LR)) {
313 			frame->tf_svc_lr = *sp;
314 			*sp++;
315 		}
316 		/*
317 		 * And the program counter. If it's not in the list skip over
318 		 * it when we return so to not hit this again.
319 		 */
320 		if (data & (1 << BIT_PC)) {
321 			frame->tf_pc = *sp;
322 			*sp++;
323 		} else
324 			frame->tf_pc += 4;
325 
326 		/* Update the stack pointer if we haven't already done so */
327 		if (update_sp)
328 			frame->tf_svc_sp = (register_t)sp;
329 		break;
330 	case DTRACE_INVOP_B:
331 		data = DTRACE_INVOP_DATA(invop) & 0x00ffffff;
332 		/* Sign extend the data */
333 		if ((data & (1 << 23)) != 0)
334 			data |= 0xff000000;
335 		/* The data is the number of 4-byte words to change the pc */
336 		data *= 4;
337 		data += 8;
338 		frame->tf_pc += data;
339 		break;
340 	default:
341 		return (-1);
342 		break;
343 	}
344 
345 	return (0);
346 }
347 
348 void dtrace_invop_init(void)
349 {
350 	dtrace_invop_jump_addr = dtrace_invop_start;
351 }
352 
353 void dtrace_invop_uninit(void)
354 {
355 	dtrace_invop_jump_addr = 0;
356 }
357