xref: /freebsd/sys/cddl/dev/dtrace/arm/dtrace_subr.c (revision 8aac90f18aef7c9eea906c3ff9a001ca7b94f375)
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 <vm/pmap.h>
43 
44 #define	DELAYBRANCH(x)	((int)(x) < 0)
45 
46 #define	BIT_PC		15
47 #define	BIT_LR		14
48 #define	BIT_SP		13
49 
50 extern dtrace_id_t	dtrace_probeid_error;
51 extern int (*dtrace_invop_jump_addr)(struct trapframe *);
52 extern void dtrace_getnanotime(struct timespec *tsp);
53 extern void dtrace_getnanouptime(struct timespec *tsp);
54 
55 int dtrace_invop(uintptr_t, struct trapframe *, uintptr_t);
56 void dtrace_invop_init(void);
57 void dtrace_invop_uninit(void);
58 
59 typedef struct dtrace_invop_hdlr {
60 	int (*dtih_func)(uintptr_t, struct trapframe *, uintptr_t);
61 	struct dtrace_invop_hdlr *dtih_next;
62 } dtrace_invop_hdlr_t;
63 
64 dtrace_invop_hdlr_t *dtrace_invop_hdlr;
65 
66 int
67 dtrace_invop(uintptr_t addr, struct trapframe *frame, uintptr_t eax)
68 {
69 	struct thread *td;
70 	dtrace_invop_hdlr_t *hdlr;
71 	int rval;
72 
73 	rval = 0;
74 	td = curthread;
75 	td->t_dtrace_trapframe = frame;
76 	for (hdlr = dtrace_invop_hdlr; hdlr != NULL; hdlr = hdlr->dtih_next)
77 		if ((rval = hdlr->dtih_func(addr, frame, eax)) != 0)
78 			break;
79 	td->t_dtrace_trapframe = NULL;
80 	return (rval);
81 }
82 
83 
84 void
85 dtrace_invop_add(int (*func)(uintptr_t, struct trapframe *, uintptr_t))
86 {
87 	dtrace_invop_hdlr_t *hdlr;
88 
89 	hdlr = kmem_alloc(sizeof (dtrace_invop_hdlr_t), KM_SLEEP);
90 	hdlr->dtih_func = func;
91 	hdlr->dtih_next = dtrace_invop_hdlr;
92 	dtrace_invop_hdlr = hdlr;
93 }
94 
95 void
96 dtrace_invop_remove(int (*func)(uintptr_t, struct trapframe *, uintptr_t))
97 {
98 	dtrace_invop_hdlr_t *hdlr = dtrace_invop_hdlr, *prev = NULL;
99 
100 	for (;;) {
101 		if (hdlr == NULL)
102 			panic("attempt to remove non-existent invop handler");
103 
104 		if (hdlr->dtih_func == func)
105 			break;
106 
107 		prev = hdlr;
108 		hdlr = hdlr->dtih_next;
109 	}
110 
111 	if (prev == NULL) {
112 		ASSERT(dtrace_invop_hdlr == hdlr);
113 		dtrace_invop_hdlr = hdlr->dtih_next;
114 	} else {
115 		ASSERT(dtrace_invop_hdlr != hdlr);
116 		prev->dtih_next = hdlr->dtih_next;
117 	}
118 
119 	kmem_free(hdlr, 0);
120 }
121 
122 
123 /*ARGSUSED*/
124 void
125 dtrace_toxic_ranges(void (*func)(uintptr_t base, uintptr_t limit))
126 {
127 
128 	/*
129 	 * There are no ranges to exclude that are common to all 32-bit arm
130 	 * platforms.  This function only needs to exclude ranges "... in
131 	 * which it is impossible to recover from such a load after it has been
132 	 * attempted." -- i.e., accessing within the range causes some sort
133 	 * fault in the system which is not handled by the normal arm
134 	 * exception-handling mechanisms.  If systems exist where that is the
135 	 * case, a method to handle this functionality would have to be added to
136 	 * the platform_if interface so that those systems could provide their
137 	 * specific toxic range(s).
138 	 */
139 }
140 
141 void
142 dtrace_xcall(processorid_t cpu, dtrace_xcall_t func, void *arg)
143 {
144 	cpuset_t cpus;
145 
146 	if (cpu == DTRACE_CPUALL)
147 		cpus = all_cpus;
148 	else
149 		CPU_SETOF(cpu, &cpus);
150 
151 	smp_rendezvous_cpus(cpus, smp_no_rendezvous_barrier, func,
152 	    smp_no_rendezvous_barrier, arg);
153 }
154 
155 static void
156 dtrace_sync_func(void)
157 {
158 }
159 
160 void
161 dtrace_sync(void)
162 {
163 	dtrace_xcall(DTRACE_CPUALL, (dtrace_xcall_t)dtrace_sync_func, NULL);
164 }
165 
166 /*
167  * DTrace needs a high resolution time function which can
168  * be called from a probe context and guaranteed not to have
169  * instrumented with probes itself.
170  *
171  * Returns nanoseconds since boot.
172  */
173 uint64_t
174 dtrace_gethrtime(void)
175 {
176 	struct	timespec curtime;
177 
178 	dtrace_getnanouptime(&curtime);
179 
180 	return (curtime.tv_sec * 1000000000UL + curtime.tv_nsec);
181 
182 }
183 
184 uint64_t
185 dtrace_gethrestime(void)
186 {
187 	struct timespec current_time;
188 
189 	dtrace_getnanotime(&current_time);
190 
191 	return (current_time.tv_sec * 1000000000UL + current_time.tv_nsec);
192 }
193 
194 /* Function to handle DTrace traps during probes. See amd64/amd64/trap.c */
195 int
196 dtrace_trap(struct trapframe *frame, u_int type)
197 {
198 	/*
199 	 * A trap can occur while DTrace executes a probe. Before
200 	 * executing the probe, DTrace blocks re-scheduling and sets
201 	 * a flag in its per-cpu flags to indicate that it doesn't
202 	 * want to fault. On returning from the probe, the no-fault
203 	 * flag is cleared and finally re-scheduling is enabled.
204 	 *
205 	 * Check if DTrace has enabled 'no-fault' mode:
206 	 *
207 	 */
208 	if ((cpu_core[curcpu].cpuc_dtrace_flags & CPU_DTRACE_NOFAULT) != 0) {
209 		/*
210 		 * There are only a couple of trap types that are expected.
211 		 * All the rest will be handled in the usual way.
212 		 */
213 		switch (type) {
214 		/* Page fault. */
215 		case FAULT_ALIGN:
216 			/* Flag a bad address. */
217 			cpu_core[curcpu].cpuc_dtrace_flags |= CPU_DTRACE_BADADDR;
218 			cpu_core[curcpu].cpuc_dtrace_illval = 0;
219 
220 			/*
221 			 * Offset the instruction pointer to the instruction
222 			 * following the one causing the fault.
223 			 */
224 			frame->tf_pc += sizeof(int);
225 			return (1);
226 		default:
227 			/* Handle all other traps in the usual way. */
228 			break;
229 		}
230 	}
231 
232 	/* Handle the trap in the usual way. */
233 	return (0);
234 }
235 
236 void
237 dtrace_probe_error(dtrace_state_t *state, dtrace_epid_t epid, int which,
238     int fault, int fltoffs, uintptr_t illval)
239 {
240 
241 	dtrace_probe(dtrace_probeid_error, (uint64_t)(uintptr_t)state,
242 	    (uintptr_t)epid,
243 	    (uintptr_t)which, (uintptr_t)fault, (uintptr_t)fltoffs);
244 }
245 
246 static int
247 dtrace_invop_start(struct trapframe *frame)
248 {
249 	register_t *r0, *sp;
250 	int data, invop, reg, update_sp;
251 
252 	invop = dtrace_invop(frame->tf_pc, frame, frame->tf_r0);
253 	switch (invop & DTRACE_INVOP_MASK) {
254 	case DTRACE_INVOP_PUSHM:
255 		sp = (register_t *)frame->tf_svc_sp;
256 		r0 = &frame->tf_r0;
257 		data = DTRACE_INVOP_DATA(invop);
258 
259 		/*
260 		 * Store the pc, lr, and sp. These have their own
261 		 * entries in the struct.
262 		 */
263 		if (data & (1 << BIT_PC)) {
264 			sp--;
265 			*sp = frame->tf_pc;
266 		}
267 		if (data & (1 << BIT_LR)) {
268 			sp--;
269 			*sp = frame->tf_svc_lr;
270 		}
271 		if (data & (1 << BIT_SP)) {
272 			sp--;
273 			*sp = frame->tf_svc_sp;
274 		}
275 
276 		/* Store the general registers */
277 		for (reg = 12; reg >= 0; reg--) {
278 			if (data & (1 << reg)) {
279 				sp--;
280 				*sp = r0[reg];
281 			}
282 		}
283 
284 		/* Update the stack pointer and program counter to continue */
285 		frame->tf_svc_sp = (register_t)sp;
286 		frame->tf_pc += 4;
287 		break;
288 	case DTRACE_INVOP_POPM:
289 		sp = (register_t *)frame->tf_svc_sp;
290 		r0 = &frame->tf_r0;
291 		data = DTRACE_INVOP_DATA(invop);
292 
293 		/* Read the general registers */
294 		for (reg = 0; reg <= 12; reg++) {
295 			if (data & (1 << reg)) {
296 				r0[reg] = *sp;
297 				sp++;
298 			}
299 		}
300 
301 		/*
302 		 * Set the stack pointer. If we don't update it here we will
303 		 * need to update it at the end as the instruction would do
304 		 */
305 		update_sp = 1;
306 		if (data & (1 << BIT_SP)) {
307 			frame->tf_svc_sp = *sp;
308 			*sp++;
309 			update_sp = 0;
310 		}
311 
312 		/* Update the link register, we need to use the correct copy */
313 		if (data & (1 << BIT_LR)) {
314 			frame->tf_svc_lr = *sp;
315 			*sp++;
316 		}
317 		/*
318 		 * And the program counter. If it's not in the list skip over
319 		 * it when we return so to not hit this again.
320 		 */
321 		if (data & (1 << BIT_PC)) {
322 			frame->tf_pc = *sp;
323 			*sp++;
324 		} else
325 			frame->tf_pc += 4;
326 
327 		/* Update the stack pointer if we haven't already done so */
328 		if (update_sp)
329 			frame->tf_svc_sp = (register_t)sp;
330 		break;
331 	case DTRACE_INVOP_B:
332 		data = DTRACE_INVOP_DATA(invop) & 0x00ffffff;
333 		/* Sign extend the data */
334 		if ((data & (1 << 23)) != 0)
335 			data |= 0xff000000;
336 		/* The data is the number of 4-byte words to change the pc */
337 		data *= 4;
338 		data += 8;
339 		frame->tf_pc += data;
340 		break;
341 	default:
342 		return (-1);
343 		break;
344 	}
345 
346 	return (0);
347 }
348 
349 void dtrace_invop_init(void)
350 {
351 	dtrace_invop_jump_addr = dtrace_invop_start;
352 }
353 
354 void dtrace_invop_uninit(void)
355 {
356 	dtrace_invop_jump_addr = 0;
357 }
358