xref: /freebsd/sys/arm64/arm64/trap.c (revision f56f82e0) 
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 
56 #ifdef KDTRACE_HOOKS
57 #include <sys/dtrace_bsd.h>
58 #endif
59 
60 #ifdef VFP
61 #include <machine/vfp.h>
62 #endif
63 
64 #ifdef KDB
65 #include <machine/db_machdep.h>
66 #endif
67 
68 #ifdef DDB
69 #include <ddb/db_output.h>
70 #endif
71 
72 extern register_t fsu_intr_fault;
73 
74 /* Called from exception.S */
75 void do_el1h_sync(struct thread *, struct trapframe *);
76 void do_el0_sync(struct thread *, struct trapframe *);
77 void do_el0_error(struct trapframe *);
78 static void print_registers(struct trapframe *frame);
79 
80 int (*dtrace_invop_jump_addr)(struct trapframe *);
81 
82 static __inline void
83 call_trapsignal(struct thread *td, int sig, int code, void *addr)
84 {
85 	ksiginfo_t ksi;
86 
87 	ksiginfo_init_trap(&ksi);
88 	ksi.ksi_signo = sig;
89 	ksi.ksi_code = code;
90 	ksi.ksi_addr = addr;
91 	trapsignal(td, &ksi);
92 }
93 
94 int
95 cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa)
96 {
97 	struct proc *p;
98 	register_t *ap;
99 	int nap;
100 
101 	nap = 8;
102 	p = td->td_proc;
103 	ap = td->td_frame->tf_x;
104 
105 	sa->code = td->td_frame->tf_x[8];
106 
107 	if (sa->code == SYS_syscall || sa->code == SYS___syscall) {
108 		sa->code = *ap++;
109 		nap--;
110 	}
111 
112 	if (p->p_sysent->sv_mask)
113 		sa->code &= p->p_sysent->sv_mask;
114 	if (sa->code >= p->p_sysent->sv_size)
115 		sa->callp = &p->p_sysent->sv_table[0];
116 	else
117 		sa->callp = &p->p_sysent->sv_table[sa->code];
118 
119 	sa->narg = sa->callp->sy_narg;
120 	memcpy(sa->args, ap, nap * sizeof(register_t));
121 	if (sa->narg > nap)
122 		panic("ARM64TODO: Could we have more than 8 args?");
123 
124 	td->td_retval[0] = 0;
125 	td->td_retval[1] = 0;
126 
127 	return (0);
128 }
129 
130 #include "../../kern/subr_syscall.c"
131 
132 static void
133 svc_handler(struct thread *td, struct trapframe *frame)
134 {
135 	struct syscall_args sa;
136 	int error;
137 
138 	if ((frame->tf_esr & ESR_ELx_ISS_MASK) == 0) {
139 		error = syscallenter(td, &sa);
140 		syscallret(td, error, &sa);
141 	} else {
142 		call_trapsignal(td, SIGILL, ILL_ILLOPN, (void *)frame->tf_elr);
143 		userret(td, frame);
144 	}
145 }
146 
147 static void
148 data_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
149     uint64_t far, int lower)
150 {
151 	struct vm_map *map;
152 	struct proc *p;
153 	struct pcb *pcb;
154 	vm_prot_t ftype;
155 	vm_offset_t va;
156 	int error, sig, ucode;
157 
158 	/*
159 	 * According to the ARMv8-A rev. A.g, B2.10.5 "Load-Exclusive
160 	 * and Store-Exclusive instruction usage restrictions", state
161 	 * of the exclusive monitors after data abort exception is unknown.
162 	 */
163 	clrex();
164 
165 #ifdef KDB
166 	if (kdb_active) {
167 		kdb_reenter();
168 		return;
169 	}
170 #endif
171 
172 	pcb = td->td_pcb;
173 
174 	/*
175 	 * Special case for fuswintr and suswintr. These can't sleep so
176 	 * handle them early on in the trap handler.
177 	 */
178 	if (__predict_false(pcb->pcb_onfault == (vm_offset_t)&fsu_intr_fault)) {
179 		frame->tf_elr = pcb->pcb_onfault;
180 		return;
181 	}
182 
183 	p = td->td_proc;
184 	if (lower)
185 		map = &p->p_vmspace->vm_map;
186 	else {
187 		/* The top bit tells us which range to use */
188 		if (far >= VM_MAXUSER_ADDRESS) {
189 			map = kernel_map;
190 		} else {
191 			map = &p->p_vmspace->vm_map;
192 			if (map == NULL)
193 				map = kernel_map;
194 		}
195 	}
196 
197 	if (pmap_fault(map->pmap, esr, far) == KERN_SUCCESS)
198 		return;
199 
200 	KASSERT(td->td_md.md_spinlock_count == 0,
201 	    ("data abort with spinlock held"));
202 	if (td->td_critnest != 0 || WITNESS_CHECK(WARN_SLEEPOK |
203 	    WARN_GIANTOK, NULL, "Kernel page fault") != 0) {
204 		print_registers(frame);
205 		printf(" far: %16lx\n", far);
206 		printf(" esr:         %.8lx\n", esr);
207 		panic("data abort in critical section or under mutex");
208 	}
209 
210 	va = trunc_page(far);
211 	ftype = ((esr >> 6) & 1) ? VM_PROT_READ | VM_PROT_WRITE : VM_PROT_READ;
212 
213 	/* Fault in the page. */
214 	error = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
215 	if (error != KERN_SUCCESS) {
216 		if (lower) {
217 			sig = SIGSEGV;
218 			if (error == KERN_PROTECTION_FAILURE)
219 				ucode = SEGV_ACCERR;
220 			else
221 				ucode = SEGV_MAPERR;
222 			call_trapsignal(td, sig, ucode, (void *)far);
223 		} else {
224 			if (td->td_intr_nesting_level == 0 &&
225 			    pcb->pcb_onfault != 0) {
226 				frame->tf_x[0] = error;
227 				frame->tf_elr = pcb->pcb_onfault;
228 				return;
229 			}
230 
231 			printf("Fatal data abort:\n");
232 			print_registers(frame);
233 			printf(" far: %16lx\n", far);
234 			printf(" esr:         %.8lx\n", esr);
235 
236 #ifdef KDB
237 			if (debugger_on_panic || kdb_active)
238 				if (kdb_trap(ESR_ELx_EXCEPTION(esr), 0, frame))
239 					return;
240 #endif
241 			panic("vm_fault failed: %lx", frame->tf_elr);
242 		}
243 	}
244 
245 	if (lower)
246 		userret(td, frame);
247 }
248 
249 static void
250 print_registers(struct trapframe *frame)
251 {
252 	u_int reg;
253 
254 	for (reg = 0; reg < nitems(frame->tf_x); reg++) {
255 		printf(" %sx%d: %16lx\n", (reg < 10) ? " " : "", reg,
256 		    frame->tf_x[reg]);
257 	}
258 	printf("  sp: %16lx\n", frame->tf_sp);
259 	printf("  lr: %16lx\n", frame->tf_lr);
260 	printf(" elr: %16lx\n", frame->tf_elr);
261 	printf("spsr:         %8x\n", frame->tf_spsr);
262 }
263 
264 void
265 do_el1h_sync(struct thread *td, struct trapframe *frame)
266 {
267 	uint32_t exception;
268 	uint64_t esr, far;
269 
270 	/* Read the esr register to get the exception details */
271 	esr = frame->tf_esr;
272 	exception = ESR_ELx_EXCEPTION(esr);
273 
274 #ifdef KDTRACE_HOOKS
275 	if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, exception))
276 		return;
277 #endif
278 
279 	CTR4(KTR_TRAP,
280 	    "do_el1_sync: curthread: %p, esr %lx, elr: %lx, frame: %p", td,
281 	    esr, frame->tf_elr, frame);
282 
283 	switch(exception) {
284 	case EXCP_FP_SIMD:
285 	case EXCP_TRAP_FP:
286 #ifdef VFP
287 		if ((td->td_pcb->pcb_fpflags & PCB_FP_KERN) != 0) {
288 			vfp_restore_state();
289 		} else
290 #endif
291 		{
292 			print_registers(frame);
293 			printf(" esr:         %.8lx\n", esr);
294 			panic("VFP exception in the kernel");
295 		}
296 		break;
297 	case EXCP_INSN_ABORT:
298 	case EXCP_DATA_ABORT:
299 		far = READ_SPECIALREG(far_el1);
300 		intr_enable();
301 		data_abort(td, frame, esr, far, 0);
302 		break;
303 	case EXCP_BRK:
304 #ifdef KDTRACE_HOOKS
305 		if ((esr & ESR_ELx_ISS_MASK) == 0x40d && \
306 		    dtrace_invop_jump_addr != 0) {
307 			dtrace_invop_jump_addr(frame);
308 			break;
309 		}
310 #endif
311 		/* FALLTHROUGH */
312 	case EXCP_WATCHPT_EL1:
313 	case EXCP_SOFTSTP_EL1:
314 #ifdef KDB
315 		kdb_trap(exception, 0, frame);
316 #else
317 		panic("No debugger in kernel.\n");
318 #endif
319 		break;
320 	default:
321 		print_registers(frame);
322 		panic("Unknown kernel exception %x esr_el1 %lx\n", exception,
323 		    esr);
324 	}
325 }
326 
327 /*
328  * The attempted execution of an instruction bit pattern that has no allocated
329  * instruction results in an exception with an unknown reason.
330  */
331 static void
332 el0_excp_unknown(struct trapframe *frame, uint64_t far)
333 {
334 	struct thread *td;
335 
336 	td = curthread;
337 	call_trapsignal(td, SIGILL, ILL_ILLTRP, (void *)far);
338 	userret(td, frame);
339 }
340 
341 void
342 do_el0_sync(struct thread *td, struct trapframe *frame)
343 {
344 	uint32_t exception;
345 	uint64_t esr, far;
346 
347 	/* Check we have a sane environment when entering from userland */
348 	KASSERT((uintptr_t)get_pcpu() >= VM_MIN_KERNEL_ADDRESS,
349 	    ("Invalid pcpu address from userland: %p (tpidr %lx)",
350 	     get_pcpu(), READ_SPECIALREG(tpidr_el1)));
351 
352 	esr = frame->tf_esr;
353 	exception = ESR_ELx_EXCEPTION(esr);
354 	switch (exception) {
355 	case EXCP_UNKNOWN:
356 	case EXCP_INSN_ABORT_L:
357 	case EXCP_DATA_ABORT_L:
358 	case EXCP_DATA_ABORT:
359 		far = READ_SPECIALREG(far_el1);
360 	}
361 	intr_enable();
362 
363 	CTR4(KTR_TRAP,
364 	    "do_el0_sync: curthread: %p, esr %lx, elr: %lx, frame: %p", td, esr,
365 	    frame->tf_elr, frame);
366 
367 	switch(exception) {
368 	case EXCP_FP_SIMD:
369 	case EXCP_TRAP_FP:
370 #ifdef VFP
371 		vfp_restore_state();
372 #else
373 		panic("VFP exception in userland");
374 #endif
375 		break;
376 	case EXCP_SVC:
377 		svc_handler(td, frame);
378 		break;
379 	case EXCP_INSN_ABORT_L:
380 	case EXCP_DATA_ABORT_L:
381 	case EXCP_DATA_ABORT:
382 		data_abort(td, frame, esr, far, 1);
383 		break;
384 	case EXCP_UNKNOWN:
385 		el0_excp_unknown(frame, far);
386 		break;
387 	case EXCP_SP_ALIGN:
388 		call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_sp);
389 		userret(td, frame);
390 		break;
391 	case EXCP_PC_ALIGN:
392 		call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_elr);
393 		userret(td, frame);
394 		break;
395 	case EXCP_BRK:
396 		call_trapsignal(td, SIGTRAP, TRAP_BRKPT, (void *)frame->tf_elr);
397 		userret(td, frame);
398 		break;
399 	case EXCP_MSR:
400 		call_trapsignal(td, SIGILL, ILL_PRVOPC, (void *)frame->tf_elr);
401 		userret(td, frame);
402 		break;
403 	case EXCP_SOFTSTP_EL0:
404 		td->td_frame->tf_spsr &= ~PSR_SS;
405 		td->td_pcb->pcb_flags &= ~PCB_SINGLE_STEP;
406 		WRITE_SPECIALREG(MDSCR_EL1,
407 		    READ_SPECIALREG(MDSCR_EL1) & ~DBG_MDSCR_SS);
408 		call_trapsignal(td, SIGTRAP, TRAP_TRACE,
409 		    (void *)frame->tf_elr);
410 		userret(td, frame);
411 		break;
412 	default:
413 		call_trapsignal(td, SIGBUS, BUS_OBJERR, (void *)frame->tf_elr);
414 		userret(td, frame);
415 		break;
416 	}
417 
418 	KASSERT((td->td_pcb->pcb_fpflags & ~PCB_FP_USERMASK) == 0,
419 	    ("Kernel VFP flags set while entering userspace"));
420 	KASSERT(
421 	    td->td_pcb->pcb_fpusaved == &td->td_pcb->pcb_fpustate,
422 	    ("Kernel VFP state in use when entering userspace"));
423 }
424 
425 void
426 do_el0_error(struct trapframe *frame)
427 {
428 
429 	panic("ARM64TODO: do_el0_error");
430 }
431 
432