xref: /freebsd/sys/cddl/dev/dtrace/arm/dtrace_subr.c (revision a259b98fa211ed87bfee58c575de4e2de94ee0fa)
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 /*
142  * DTrace needs a high resolution time function which can
143  * be called from a probe context and guaranteed not to have
144  * instrumented with probes itself.
145  *
146  * Returns nanoseconds since boot.
147  */
148 uint64_t
149 dtrace_gethrtime(void)
150 {
151 	struct	timespec curtime;
152 
153 	dtrace_getnanouptime(&curtime);
154 
155 	return (curtime.tv_sec * 1000000000UL + curtime.tv_nsec);
156 
157 }
158 
159 uint64_t
160 dtrace_gethrestime(void)
161 {
162 	struct timespec current_time;
163 
164 	dtrace_getnanotime(&current_time);
165 
166 	return (current_time.tv_sec * 1000000000UL + current_time.tv_nsec);
167 }
168 
169 /* Function to handle DTrace traps during probes. See arm/arm/trap-v6.c */
170 int
171 dtrace_trap(struct trapframe *frame, u_int type)
172 {
173 	/*
174 	 * A trap can occur while DTrace executes a probe. Before
175 	 * executing the probe, DTrace blocks re-scheduling and sets
176 	 * a flag in its per-cpu flags to indicate that it doesn't
177 	 * want to fault. On returning from the probe, the no-fault
178 	 * flag is cleared and finally re-scheduling is enabled.
179 	 *
180 	 * Check if DTrace has enabled 'no-fault' mode:
181 	 *
182 	 */
183 	if ((cpu_core[curcpu].cpuc_dtrace_flags & CPU_DTRACE_NOFAULT) != 0) {
184 		/*
185 		 * There are only a couple of trap types that are expected.
186 		 * All the rest will be handled in the usual way.
187 		 */
188 		switch (type) {
189 		/* Page fault. */
190 		case FAULT_PERM_L1:
191 		case FAULT_PERM_L2:
192 		case FAULT_TRAN_L1:
193 		case FAULT_TRAN_L2:
194 			/* Flag a bad address. */
195 			/* XXX FAR is missing from the trapframe */
196 			cpu_core[curcpu].cpuc_dtrace_flags |= CPU_DTRACE_BADADDR;
197 			cpu_core[curcpu].cpuc_dtrace_illval = 0;
198 
199 			/*
200 			 * Offset the instruction pointer to the instruction
201 			 * following the one causing the fault.
202 			 */
203 			frame->tf_pc += sizeof(int);
204 			return (1);
205 		default:
206 			/* Handle all other traps in the usual way. */
207 			break;
208 		}
209 	}
210 
211 	/* Handle the trap in the usual way. */
212 	return (0);
213 }
214 
215 void
216 dtrace_probe_error(dtrace_state_t *state, dtrace_epid_t epid, int which,
217     int fault, int fltoffs, uintptr_t illval)
218 {
219 
220 	dtrace_probe(dtrace_probeid_error, (uint64_t)(uintptr_t)state,
221 	    (uintptr_t)epid,
222 	    (uintptr_t)which, (uintptr_t)fault, (uintptr_t)fltoffs);
223 }
224 
225 static int
226 dtrace_invop_start(struct trapframe *frame)
227 {
228 	register_t *r0, *sp;
229 	int data, invop, reg, update_sp;
230 
231 	invop = dtrace_invop(frame->tf_pc, frame, frame->tf_r0);
232 	switch (invop & DTRACE_INVOP_MASK) {
233 	case DTRACE_INVOP_PUSHM:
234 		sp = (register_t *)frame->tf_svc_sp;
235 		r0 = &frame->tf_r0;
236 		data = DTRACE_INVOP_DATA(invop);
237 
238 		/*
239 		 * Store the pc, lr, and sp. These have their own
240 		 * entries in the struct.
241 		 */
242 		if (data & (1 << BIT_PC)) {
243 			sp--;
244 			*sp = frame->tf_pc;
245 		}
246 		if (data & (1 << BIT_LR)) {
247 			sp--;
248 			*sp = frame->tf_svc_lr;
249 		}
250 		if (data & (1 << BIT_SP)) {
251 			sp--;
252 			*sp = frame->tf_svc_sp;
253 		}
254 
255 		/* Store the general registers */
256 		for (reg = 12; reg >= 0; reg--) {
257 			if (data & (1 << reg)) {
258 				sp--;
259 				*sp = r0[reg];
260 			}
261 		}
262 
263 		/* Update the stack pointer and program counter to continue */
264 		frame->tf_svc_sp = (register_t)sp;
265 		frame->tf_pc += 4;
266 		break;
267 	case DTRACE_INVOP_POPM:
268 		sp = (register_t *)frame->tf_svc_sp;
269 		r0 = &frame->tf_r0;
270 		data = DTRACE_INVOP_DATA(invop);
271 
272 		/* Read the general registers */
273 		for (reg = 0; reg <= 12; reg++) {
274 			if (data & (1 << reg)) {
275 				r0[reg] = *sp;
276 				sp++;
277 			}
278 		}
279 
280 		/*
281 		 * Set the stack pointer. If we don't update it here we will
282 		 * need to update it at the end as the instruction would do
283 		 */
284 		update_sp = 1;
285 		if (data & (1 << BIT_SP)) {
286 			frame->tf_svc_sp = *sp;
287 			*sp++;
288 			update_sp = 0;
289 		}
290 
291 		/* Update the link register, we need to use the correct copy */
292 		if (data & (1 << BIT_LR)) {
293 			frame->tf_svc_lr = *sp;
294 			*sp++;
295 		}
296 		/*
297 		 * And the program counter. If it's not in the list skip over
298 		 * it when we return so to not hit this again.
299 		 */
300 		if (data & (1 << BIT_PC)) {
301 			frame->tf_pc = *sp;
302 			*sp++;
303 		} else
304 			frame->tf_pc += 4;
305 
306 		/* Update the stack pointer if we haven't already done so */
307 		if (update_sp)
308 			frame->tf_svc_sp = (register_t)sp;
309 		break;
310 	case DTRACE_INVOP_B:
311 		data = DTRACE_INVOP_DATA(invop) & 0x00ffffff;
312 		/* Sign extend the data */
313 		if ((data & (1 << 23)) != 0)
314 			data |= 0xff000000;
315 		/* The data is the number of 4-byte words to change the pc */
316 		data *= 4;
317 		data += 8;
318 		frame->tf_pc += data;
319 		break;
320 	default:
321 		return (-1);
322 		break;
323 	}
324 
325 	return (0);
326 }
327 
328 void dtrace_invop_init(void)
329 {
330 	dtrace_invop_jump_addr = dtrace_invop_start;
331 }
332 
333 void dtrace_invop_uninit(void)
334 {
335 	dtrace_invop_jump_addr = 0;
336 }
337