xref: /freebsd/sys/cddl/dev/dtrace/riscv/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  * Portions Copyright 2016-2018 Ruslan Bukin <br@bsdpad.com>
23  *
24  * $FreeBSD$
25  *
26  */
27 /*
28  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
29  * Use is subject to license terms.
30  */
31 
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/kernel.h>
35 #include <sys/malloc.h>
36 #include <sys/kmem.h>
37 #include <sys/proc.h>
38 #include <sys/smp.h>
39 #include <sys/dtrace_impl.h>
40 #include <sys/dtrace_bsd.h>
41 #include <cddl/dev/dtrace/dtrace_cddl.h>
42 #include <machine/vmparam.h>
43 #include <machine/encoding.h>
44 #include <machine/riscvreg.h>
45 #include <machine/clock.h>
46 #include <machine/frame.h>
47 #include <machine/trap.h>
48 #include <vm/pmap.h>
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 *);
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)
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, 0)) != 0)
78 			break;
79 	td->t_dtrace_trapframe = NULL;
80 	return (rval);
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, *prev;
98 
99 	hdlr = dtrace_invop_hdlr;
100 	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 /*ARGSUSED*/
125 void
126 dtrace_toxic_ranges(void (*func)(uintptr_t base, uintptr_t limit))
127 {
128 
129 	(*func)(0, (uintptr_t)VM_MIN_KERNEL_ADDRESS);
130 }
131 
132 void
133 dtrace_xcall(processorid_t cpu, dtrace_xcall_t func, void *arg)
134 {
135 	cpuset_t cpus;
136 
137 	if (cpu == DTRACE_CPUALL)
138 		cpus = all_cpus;
139 	else
140 		CPU_SETOF(cpu, &cpus);
141 
142 	smp_rendezvous_cpus(cpus, smp_no_rendezvous_barrier, func,
143 	    smp_no_rendezvous_barrier, arg);
144 }
145 
146 static void
147 dtrace_sync_func(void)
148 {
149 
150 }
151 
152 void
153 dtrace_sync(void)
154 {
155 
156 	dtrace_xcall(DTRACE_CPUALL, (dtrace_xcall_t)dtrace_sync_func, NULL);
157 }
158 
159 /*
160  * DTrace needs a high resolution time function which can
161  * be called from a probe context and guaranteed not to have
162  * instrumented with probes itself.
163  *
164  * Returns nanoseconds since boot.
165  */
166 uint64_t
167 dtrace_gethrtime(void)
168 {
169 	struct timespec curtime;
170 
171 	dtrace_getnanouptime(&curtime);
172 
173 	return (curtime.tv_sec * 1000000000UL + curtime.tv_nsec);
174 
175 }
176 
177 uint64_t
178 dtrace_gethrestime(void)
179 {
180 	struct timespec current_time;
181 
182 	dtrace_getnanotime(&current_time);
183 
184 	return (current_time.tv_sec * 1000000000UL + current_time.tv_nsec);
185 }
186 
187 /* Function to handle DTrace traps during probes. See riscv/riscv/trap.c */
188 int
189 dtrace_trap(struct trapframe *frame, u_int type)
190 {
191 	/*
192 	 * A trap can occur while DTrace executes a probe. Before
193 	 * executing the probe, DTrace blocks re-scheduling and sets
194 	 * a flag in its per-cpu flags to indicate that it doesn't
195 	 * want to fault. On returning from the probe, the no-fault
196 	 * flag is cleared and finally re-scheduling is enabled.
197 	 *
198 	 * Check if DTrace has enabled 'no-fault' mode:
199 	 *
200 	 */
201 
202 	if ((cpu_core[curcpu].cpuc_dtrace_flags & CPU_DTRACE_NOFAULT) != 0) {
203 		/*
204 		 * There are only a couple of trap types that are expected.
205 		 * All the rest will be handled in the usual way.
206 		 */
207 		switch (type) {
208 		case SCAUSE_LOAD_ACCESS_FAULT:
209 		case SCAUSE_STORE_ACCESS_FAULT:
210 		case SCAUSE_INST_ACCESS_FAULT:
211 			/* Flag a bad address. */
212 			cpu_core[curcpu].cpuc_dtrace_flags |= CPU_DTRACE_BADADDR;
213 			cpu_core[curcpu].cpuc_dtrace_illval = 0;
214 
215 			/*
216 			 * Offset the instruction pointer to the instruction
217 			 * following the one causing the fault.
218 			 */
219 			frame->tf_sepc += 4;
220 
221 			return (1);
222 		default:
223 			/* Handle all other traps in the usual way. */
224 			break;
225 		}
226 	}
227 
228 	/* Handle the trap in the usual way. */
229 	return (0);
230 }
231 
232 void
233 dtrace_probe_error(dtrace_state_t *state, dtrace_epid_t epid, int which,
234     int fault, int fltoffs, uintptr_t illval)
235 {
236 
237 	dtrace_probe(dtrace_probeid_error, (uint64_t)(uintptr_t)state,
238 	    (uintptr_t)epid,
239 	    (uintptr_t)which, (uintptr_t)fault, (uintptr_t)fltoffs);
240 }
241 
242 static int
243 match_opcode(uint32_t insn, int match, int mask)
244 {
245 
246 	if (((insn ^ match) & mask) == 0)
247 		return (1);
248 
249 	return (0);
250 }
251 
252 static int
253 dtrace_invop_start(struct trapframe *frame)
254 {
255 	register_t *sp;
256 	uint32_t uimm;
257 	uint32_t imm;
258 	int invop;
259 
260 	invop = dtrace_invop(frame->tf_sepc, frame);
261 	if (invop == 0)
262 		return (-1);
263 
264 	if (match_opcode(invop, (MATCH_SD | RS2_RA | RS1_SP),
265 	    (MASK_SD | RS2_MASK | RS1_MASK))) {
266 		/* Non-compressed store of ra to sp */
267 		imm = (invop >> 7) & 0x1f;
268 		imm |= ((invop >> 25) & 0x7f) << 5;
269 		sp = (register_t *)((uint8_t *)frame->tf_sp + imm);
270 		*sp = frame->tf_ra;
271 		frame->tf_sepc += INSN_SIZE;
272 		return (0);
273 	}
274 
275 	if (match_opcode(invop, (MATCH_JALR | (X_RA << RS1_SHIFT)),
276 	    (MASK_JALR | RD_MASK | RS1_MASK | IMM_MASK))) {
277 		/* Non-compressed ret */
278 		frame->tf_sepc = frame->tf_ra;
279 		return (0);
280 	}
281 
282 	if (match_opcode(invop, (MATCH_C_SDSP | RS2_C_RA),
283 	    (MASK_C_SDSP | RS2_C_MASK))) {
284 		/* 'C'-compressed store of ra to sp */
285 		uimm = ((invop >> 10) & 0x7) << 3;
286 		uimm |= ((invop >> 7) & 0x7) << 6;
287 		sp = (register_t *)((uint8_t *)frame->tf_sp + uimm);
288 		*sp = frame->tf_ra;
289 		frame->tf_sepc += INSN_C_SIZE;
290 		return (0);
291 	}
292 
293 	if (match_opcode(invop, (MATCH_C_JR | (X_RA << RD_SHIFT)),
294 	    (MASK_C_JR | RD_MASK))) {
295 		/* 'C'-compressed ret */
296 		frame->tf_sepc = frame->tf_ra;
297 		return (0);
298 	}
299 
300 #ifdef INVARIANTS
301 	panic("Instruction %x doesn't match any opcode.", invop);
302 #endif
303 
304 	return (-1);
305 }
306 
307 void
308 dtrace_invop_init(void)
309 {
310 
311 	dtrace_invop_jump_addr = dtrace_invop_start;
312 }
313 
314 void
315 dtrace_invop_uninit(void)
316 {
317 
318 	dtrace_invop_jump_addr = 0;
319 }
320