xref: /freebsd/sys/arm64/arm64/trap.c (revision 38069501) 
1 /*-
2  * Copyright (c) 2014 Andrew Turner
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  */
27 
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30 
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/kernel.h>
34 #include <sys/lock.h>
35 #include <sys/mutex.h>
36 #include <sys/pioctl.h>
37 #include <sys/proc.h>
38 #include <sys/ptrace.h>
39 #include <sys/syscall.h>
40 #include <sys/sysent.h>
41 #ifdef KDB
42 #include <sys/kdb.h>
43 #endif
44 
45 #include <vm/vm.h>
46 #include <vm/pmap.h>
47 #include <vm/vm_kern.h>
48 #include <vm/vm_map.h>
49 #include <vm/vm_param.h>
50 #include <vm/vm_extern.h>
51 
52 #include <machine/frame.h>
53 #include <machine/pcb.h>
54 #include <machine/pcpu.h>
55 #include <machine/undefined.h>
56 
57 #ifdef KDTRACE_HOOKS
58 #include <sys/dtrace_bsd.h>
59 #endif
60 
61 #ifdef VFP
62 #include <machine/vfp.h>
63 #endif
64 
65 #ifdef KDB
66 #include <machine/db_machdep.h>
67 #endif
68 
69 #ifdef DDB
70 #include <ddb/db_output.h>
71 #endif
72 
73 extern register_t fsu_intr_fault;
74 
75 /* Called from exception.S */
76 void do_el1h_sync(struct thread *, struct trapframe *);
77 void do_el0_sync(struct thread *, struct trapframe *);
78 void do_el0_error(struct trapframe *);
79 static void print_registers(struct trapframe *frame);
80 
81 int (*dtrace_invop_jump_addr)(struct trapframe *);
82 
83 static __inline void
84 call_trapsignal(struct thread *td, int sig, int code, void *addr)
85 {
86 	ksiginfo_t ksi;
87 
88 	ksiginfo_init_trap(&ksi);
89 	ksi.ksi_signo = sig;
90 	ksi.ksi_code = code;
91 	ksi.ksi_addr = addr;
92 	trapsignal(td, &ksi);
93 }
94 
95 int
96 cpu_fetch_syscall_args(struct thread *td)
97 {
98 	struct proc *p;
99 	register_t *ap;
100 	struct syscall_args *sa;
101 	int nap;
102 
103 	nap = 8;
104 	p = td->td_proc;
105 	ap = td->td_frame->tf_x;
106 	sa = &td->td_sa;
107 
108 	sa->code = td->td_frame->tf_x[8];
109 
110 	if (sa->code == SYS_syscall || sa->code == SYS___syscall) {
111 		sa->code = *ap++;
112 		nap--;
113 	}
114 
115 	if (p->p_sysent->sv_mask)
116 		sa->code &= p->p_sysent->sv_mask;
117 	if (sa->code >= p->p_sysent->sv_size)
118 		sa->callp = &p->p_sysent->sv_table[0];
119 	else
120 		sa->callp = &p->p_sysent->sv_table[sa->code];
121 
122 	sa->narg = sa->callp->sy_narg;
123 	memcpy(sa->args, ap, nap * sizeof(register_t));
124 	if (sa->narg > nap)
125 		panic("ARM64TODO: Could we have more than 8 args?");
126 
127 	td->td_retval[0] = 0;
128 	td->td_retval[1] = 0;
129 
130 	return (0);
131 }
132 
133 #include "../../kern/subr_syscall.c"
134 
135 static void
136 svc_handler(struct thread *td, struct trapframe *frame)
137 {
138 	int error;
139 
140 	if ((frame->tf_esr & ESR_ELx_ISS_MASK) == 0) {
141 		error = syscallenter(td);
142 		syscallret(td, error);
143 	} else {
144 		call_trapsignal(td, SIGILL, ILL_ILLOPN, (void *)frame->tf_elr);
145 		userret(td, frame);
146 	}
147 }
148 
149 static void
150 data_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
151     uint64_t far, int lower)
152 {
153 	struct vm_map *map;
154 	struct proc *p;
155 	struct pcb *pcb;
156 	vm_prot_t ftype;
157 	vm_offset_t va;
158 	int error, sig, ucode;
159 
160 	/*
161 	 * According to the ARMv8-A rev. A.g, B2.10.5 "Load-Exclusive
162 	 * and Store-Exclusive instruction usage restrictions", state
163 	 * of the exclusive monitors after data abort exception is unknown.
164 	 */
165 	clrex();
166 
167 #ifdef KDB
168 	if (kdb_active) {
169 		kdb_reenter();
170 		return;
171 	}
172 #endif
173 
174 	pcb = td->td_pcb;
175 
176 	/*
177 	 * Special case for fuswintr and suswintr. These can't sleep so
178 	 * handle them early on in the trap handler.
179 	 */
180 	if (__predict_false(pcb->pcb_onfault == (vm_offset_t)&fsu_intr_fault)) {
181 		frame->tf_elr = pcb->pcb_onfault;
182 		return;
183 	}
184 
185 	p = td->td_proc;
186 	if (lower)
187 		map = &p->p_vmspace->vm_map;
188 	else {
189 		/* The top bit tells us which range to use */
190 		if (far >= VM_MAXUSER_ADDRESS) {
191 			map = kernel_map;
192 		} else {
193 			map = &p->p_vmspace->vm_map;
194 			if (map == NULL)
195 				map = kernel_map;
196 		}
197 	}
198 
199 	if (pmap_fault(map->pmap, esr, far) == KERN_SUCCESS)
200 		return;
201 
202 	KASSERT(td->td_md.md_spinlock_count == 0,
203 	    ("data abort with spinlock held"));
204 	if (td->td_critnest != 0 || WITNESS_CHECK(WARN_SLEEPOK |
205 	    WARN_GIANTOK, NULL, "Kernel page fault") != 0) {
206 		print_registers(frame);
207 		printf(" far: %16lx\n", far);
208 		printf(" esr:         %.8lx\n", esr);
209 		panic("data abort in critical section or under mutex");
210 	}
211 
212 	va = trunc_page(far);
213 	ftype = ((esr >> 6) & 1) ? VM_PROT_READ | VM_PROT_WRITE : VM_PROT_READ;
214 
215 	/* Fault in the page. */
216 	error = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
217 	if (error != KERN_SUCCESS) {
218 		if (lower) {
219 			sig = SIGSEGV;
220 			if (error == KERN_PROTECTION_FAILURE)
221 				ucode = SEGV_ACCERR;
222 			else
223 				ucode = SEGV_MAPERR;
224 			call_trapsignal(td, sig, ucode, (void *)far);
225 		} else {
226 			if (td->td_intr_nesting_level == 0 &&
227 			    pcb->pcb_onfault != 0) {
228 				frame->tf_x[0] = error;
229 				frame->tf_elr = pcb->pcb_onfault;
230 				return;
231 			}
232 
233 			printf("Fatal data abort:\n");
234 			print_registers(frame);
235 			printf(" far: %16lx\n", far);
236 			printf(" esr:         %.8lx\n", esr);
237 
238 #ifdef KDB
239 			if (debugger_on_panic || kdb_active)
240 				if (kdb_trap(ESR_ELx_EXCEPTION(esr), 0, frame))
241 					return;
242 #endif
243 			panic("vm_fault failed: %lx", frame->tf_elr);
244 		}
245 	}
246 
247 	if (lower)
248 		userret(td, frame);
249 }
250 
251 static void
252 print_registers(struct trapframe *frame)
253 {
254 	u_int reg;
255 
256 	for (reg = 0; reg < nitems(frame->tf_x); reg++) {
257 		printf(" %sx%d: %16lx\n", (reg < 10) ? " " : "", reg,
258 		    frame->tf_x[reg]);
259 	}
260 	printf("  sp: %16lx\n", frame->tf_sp);
261 	printf("  lr: %16lx\n", frame->tf_lr);
262 	printf(" elr: %16lx\n", frame->tf_elr);
263 	printf("spsr:         %8x\n", frame->tf_spsr);
264 }
265 
266 void
267 do_el1h_sync(struct thread *td, struct trapframe *frame)
268 {
269 	struct trapframe *oframe;
270 	uint32_t exception;
271 	uint64_t esr, far;
272 
273 	/* Read the esr register to get the exception details */
274 	esr = frame->tf_esr;
275 	exception = ESR_ELx_EXCEPTION(esr);
276 
277 #ifdef KDTRACE_HOOKS
278 	if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, exception))
279 		return;
280 #endif
281 
282 	CTR4(KTR_TRAP,
283 	    "do_el1_sync: curthread: %p, esr %lx, elr: %lx, frame: %p", td,
284 	    esr, frame->tf_elr, frame);
285 
286 	oframe = td->td_frame;
287 
288 	switch (exception) {
289 	case EXCP_BRK:
290 	case EXCP_WATCHPT_EL1:
291 	case EXCP_SOFTSTP_EL1:
292 		break;
293 	default:
294 		td->td_frame = frame;
295 		break;
296 	}
297 
298 	switch(exception) {
299 	case EXCP_FP_SIMD:
300 	case EXCP_TRAP_FP:
301 #ifdef VFP
302 		if ((td->td_pcb->pcb_fpflags & PCB_FP_KERN) != 0) {
303 			vfp_restore_state();
304 		} else
305 #endif
306 		{
307 			print_registers(frame);
308 			printf(" esr:         %.8lx\n", esr);
309 			panic("VFP exception in the kernel");
310 		}
311 		break;
312 	case EXCP_INSN_ABORT:
313 	case EXCP_DATA_ABORT:
314 		far = READ_SPECIALREG(far_el1);
315 		intr_enable();
316 		data_abort(td, frame, esr, far, 0);
317 		break;
318 	case EXCP_BRK:
319 #ifdef KDTRACE_HOOKS
320 		if ((esr & ESR_ELx_ISS_MASK) == 0x40d && \
321 		    dtrace_invop_jump_addr != 0) {
322 			dtrace_invop_jump_addr(frame);
323 			break;
324 		}
325 #endif
326 		/* FALLTHROUGH */
327 	case EXCP_WATCHPT_EL1:
328 	case EXCP_SOFTSTP_EL1:
329 #ifdef KDB
330 		kdb_trap(exception, 0,
331 		    (td->td_frame != NULL) ? td->td_frame : frame);
332 #else
333 		panic("No debugger in kernel.\n");
334 #endif
335 		break;
336 	case EXCP_UNKNOWN:
337 		if (undef_insn(1, frame))
338 			break;
339 		/* FALLTHROUGH */
340 	default:
341 		print_registers(frame);
342 		panic("Unknown kernel exception %x esr_el1 %lx\n", exception,
343 		    esr);
344 	}
345 
346 	td->td_frame = oframe;
347 }
348 
349 void
350 do_el0_sync(struct thread *td, struct trapframe *frame)
351 {
352 	uint32_t exception;
353 	uint64_t esr, far;
354 
355 	/* Check we have a sane environment when entering from userland */
356 	KASSERT((uintptr_t)get_pcpu() >= VM_MIN_KERNEL_ADDRESS,
357 	    ("Invalid pcpu address from userland: %p (tpidr %lx)",
358 	     get_pcpu(), READ_SPECIALREG(tpidr_el1)));
359 
360 	esr = frame->tf_esr;
361 	exception = ESR_ELx_EXCEPTION(esr);
362 	switch (exception) {
363 	case EXCP_UNKNOWN:
364 	case EXCP_INSN_ABORT_L:
365 	case EXCP_DATA_ABORT_L:
366 	case EXCP_DATA_ABORT:
367 		far = READ_SPECIALREG(far_el1);
368 	}
369 	intr_enable();
370 
371 	CTR4(KTR_TRAP,
372 	    "do_el0_sync: curthread: %p, esr %lx, elr: %lx, frame: %p", td, esr,
373 	    frame->tf_elr, frame);
374 
375 	switch(exception) {
376 	case EXCP_FP_SIMD:
377 	case EXCP_TRAP_FP:
378 #ifdef VFP
379 		vfp_restore_state();
380 #else
381 		panic("VFP exception in userland");
382 #endif
383 		break;
384 	case EXCP_SVC:
385 		svc_handler(td, frame);
386 		break;
387 	case EXCP_INSN_ABORT_L:
388 	case EXCP_DATA_ABORT_L:
389 	case EXCP_DATA_ABORT:
390 		data_abort(td, frame, esr, far, 1);
391 		break;
392 	case EXCP_UNKNOWN:
393 		if (!undef_insn(0, frame))
394 			call_trapsignal(td, SIGILL, ILL_ILLTRP, (void *)far);
395 		userret(td, frame);
396 		break;
397 	case EXCP_SP_ALIGN:
398 		call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_sp);
399 		userret(td, frame);
400 		break;
401 	case EXCP_PC_ALIGN:
402 		call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_elr);
403 		userret(td, frame);
404 		break;
405 	case EXCP_BRK:
406 		call_trapsignal(td, SIGTRAP, TRAP_BRKPT, (void *)frame->tf_elr);
407 		userret(td, frame);
408 		break;
409 	case EXCP_MSR:
410 		call_trapsignal(td, SIGILL, ILL_PRVOPC, (void *)frame->tf_elr);
411 		userret(td, frame);
412 		break;
413 	case EXCP_SOFTSTP_EL0:
414 		td->td_frame->tf_spsr &= ~PSR_SS;
415 		td->td_pcb->pcb_flags &= ~PCB_SINGLE_STEP;
416 		WRITE_SPECIALREG(MDSCR_EL1,
417 		    READ_SPECIALREG(MDSCR_EL1) & ~DBG_MDSCR_SS);
418 		call_trapsignal(td, SIGTRAP, TRAP_TRACE,
419 		    (void *)frame->tf_elr);
420 		userret(td, frame);
421 		break;
422 	default:
423 		call_trapsignal(td, SIGBUS, BUS_OBJERR, (void *)frame->tf_elr);
424 		userret(td, frame);
425 		break;
426 	}
427 
428 	KASSERT((td->td_pcb->pcb_fpflags & ~PCB_FP_USERMASK) == 0,
429 	    ("Kernel VFP flags set while entering userspace"));
430 	KASSERT(
431 	    td->td_pcb->pcb_fpusaved == &td->td_pcb->pcb_fpustate,
432 	    ("Kernel VFP state in use when entering userspace"));
433 }
434 
435 void
436 do_el0_error(struct trapframe *frame)
437 {
438 
439 	panic("ARM64TODO: do_el0_error");
440 }
441 
442