xref: /freebsd/sys/arm64/arm64/trap.c (revision 076ad2f8) 
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 trapframe *);
76 void do_el0_sync(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 trapframe *frame)
134 {
135 	struct syscall_args sa;
136 	struct thread *td;
137 	int error;
138 
139 	td = curthread;
140 
141 	error = syscallenter(td, &sa);
142 	syscallret(td, error, &sa);
143 }
144 
145 static void
146 data_abort(struct trapframe *frame, uint64_t esr, uint64_t far, int lower)
147 {
148 	struct vm_map *map;
149 	struct thread *td;
150 	struct proc *p;
151 	struct pcb *pcb;
152 	vm_prot_t ftype;
153 	vm_offset_t va;
154 	int error, sig, ucode;
155 
156 	/*
157 	 * According to the ARMv8-A rev. A.g, B2.10.5 "Load-Exclusive
158 	 * and Store-Exclusive instruction usage restrictions", state
159 	 * of the exclusive monitors after data abort exception is unknown.
160 	 */
161 	clrex();
162 
163 #ifdef KDB
164 	if (kdb_active) {
165 		kdb_reenter();
166 		return;
167 	}
168 #endif
169 
170 	td = curthread;
171 	pcb = td->td_pcb;
172 
173 	/*
174 	 * Special case for fuswintr and suswintr. These can't sleep so
175 	 * handle them early on in the trap handler.
176 	 */
177 	if (__predict_false(pcb->pcb_onfault == (vm_offset_t)&fsu_intr_fault)) {
178 		frame->tf_elr = pcb->pcb_onfault;
179 		return;
180 	}
181 
182 	p = td->td_proc;
183 	if (lower)
184 		map = &p->p_vmspace->vm_map;
185 	else {
186 		/* The top bit tells us which range to use */
187 		if ((far >> 63) == 1) {
188 			map = kernel_map;
189 		} else {
190 			map = &p->p_vmspace->vm_map;
191 			if (map == NULL)
192 				map = kernel_map;
193 		}
194 	}
195 
196 	if (pmap_fault(map->pmap, esr, far) == KERN_SUCCESS)
197 		return;
198 
199 	KASSERT(td->td_md.md_spinlock_count == 0,
200 	    ("data abort with spinlock held"));
201 	if (td->td_critnest != 0 || WITNESS_CHECK(WARN_SLEEPOK |
202 	    WARN_GIANTOK, NULL, "Kernel page fault") != 0) {
203 		print_registers(frame);
204 		printf(" far: %16lx\n", far);
205 		printf(" esr:         %.8lx\n", esr);
206 		panic("data abort in critical section or under mutex");
207 	}
208 
209 	va = trunc_page(far);
210 	ftype = ((esr >> 6) & 1) ? VM_PROT_READ | VM_PROT_WRITE : VM_PROT_READ;
211 
212 	/* Fault in the page. */
213 	error = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
214 	if (error != KERN_SUCCESS) {
215 		if (lower) {
216 			sig = SIGSEGV;
217 			if (error == KERN_PROTECTION_FAILURE)
218 				ucode = SEGV_ACCERR;
219 			else
220 				ucode = SEGV_MAPERR;
221 			call_trapsignal(td, sig, ucode, (void *)far);
222 		} else {
223 			if (td->td_intr_nesting_level == 0 &&
224 			    pcb->pcb_onfault != 0) {
225 				frame->tf_x[0] = error;
226 				frame->tf_elr = pcb->pcb_onfault;
227 				return;
228 			}
229 
230 			printf("Fatal data abort:\n");
231 			print_registers(frame);
232 			printf(" far: %16lx\n", far);
233 			printf(" esr:         %.8lx\n", esr);
234 
235 #ifdef KDB
236 			if (debugger_on_panic || kdb_active)
237 				if (kdb_trap(ESR_ELx_EXCEPTION(esr), 0, frame))
238 					return;
239 #endif
240 			panic("vm_fault failed: %lx", frame->tf_elr);
241 		}
242 	}
243 
244 	if (lower)
245 		userret(td, frame);
246 }
247 
248 static void
249 print_registers(struct trapframe *frame)
250 {
251 	u_int reg;
252 
253 	for (reg = 0; reg < nitems(frame->tf_x); reg++) {
254 		printf(" %sx%d: %16lx\n", (reg < 10) ? " " : "", reg,
255 		    frame->tf_x[reg]);
256 	}
257 	printf("  sp: %16lx\n", frame->tf_sp);
258 	printf("  lr: %16lx\n", frame->tf_lr);
259 	printf(" elr: %16lx\n", frame->tf_elr);
260 	printf("spsr:         %8x\n", frame->tf_spsr);
261 }
262 
263 void
264 do_el1h_sync(struct trapframe *frame)
265 {
266 	uint32_t exception;
267 	uint64_t esr, far;
268 
269 	/* Read the esr register to get the exception details */
270 	esr = frame->tf_esr;
271 	exception = ESR_ELx_EXCEPTION(esr);
272 
273 #ifdef KDTRACE_HOOKS
274 	if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, exception))
275 		return;
276 #endif
277 
278 	CTR4(KTR_TRAP,
279 	    "do_el1_sync: curthread: %p, esr %lx, elr: %lx, frame: %p",
280 	    curthread, esr, frame->tf_elr, frame);
281 
282 	switch(exception) {
283 	case EXCP_FP_SIMD:
284 	case EXCP_TRAP_FP:
285 #ifdef VFP
286 		if ((curthread->td_pcb->pcb_fpflags & PCB_FP_KERN) != 0) {
287 			vfp_restore_state();
288 		} else
289 #endif
290 		{
291 			print_registers(frame);
292 			printf(" esr:         %.8lx\n", esr);
293 			panic("VFP exception in the kernel");
294 		}
295 		break;
296 	case EXCP_INSN_ABORT:
297 	case EXCP_DATA_ABORT:
298 		far = READ_SPECIALREG(far_el1);
299 		intr_enable();
300 		data_abort(frame, esr, far, 0);
301 		break;
302 	case EXCP_BRK:
303 #ifdef KDTRACE_HOOKS
304 		if ((esr & ESR_ELx_ISS_MASK) == 0x40d && \
305 		    dtrace_invop_jump_addr != 0) {
306 			dtrace_invop_jump_addr(frame);
307 			break;
308 		}
309 #endif
310 		/* FALLTHROUGH */
311 	case EXCP_WATCHPT_EL1:
312 	case EXCP_SOFTSTP_EL1:
313 #ifdef KDB
314 		kdb_trap(exception, 0, frame);
315 #else
316 		panic("No debugger in kernel.\n");
317 #endif
318 		break;
319 	default:
320 		print_registers(frame);
321 		panic("Unknown kernel exception %x esr_el1 %lx\n", exception,
322 		    esr);
323 	}
324 }
325 
326 /*
327  * The attempted execution of an instruction bit pattern that has no allocated
328  * instruction results in an exception with an unknown reason.
329  */
330 static void
331 el0_excp_unknown(struct trapframe *frame, uint64_t far)
332 {
333 	struct thread *td;
334 
335 	td = curthread;
336 	call_trapsignal(td, SIGILL, ILL_ILLTRP, (void *)far);
337 	userret(td, frame);
338 }
339 
340 void
341 do_el0_sync(struct trapframe *frame)
342 {
343 	struct thread *td;
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 	td = curthread;
353 	td->td_frame = frame;
354 
355 	esr = frame->tf_esr;
356 	exception = ESR_ELx_EXCEPTION(esr);
357 	switch (exception) {
358 	case EXCP_UNKNOWN:
359 	case EXCP_INSN_ABORT_L:
360 	case EXCP_DATA_ABORT_L:
361 	case EXCP_DATA_ABORT:
362 		far = READ_SPECIALREG(far_el1);
363 	}
364 	intr_enable();
365 
366 	CTR4(KTR_TRAP,
367 	    "do_el0_sync: curthread: %p, esr %lx, elr: %lx, frame: %p",
368 	    curthread, esr, frame->tf_elr, frame);
369 
370 	switch(exception) {
371 	case EXCP_FP_SIMD:
372 	case EXCP_TRAP_FP:
373 #ifdef VFP
374 		vfp_restore_state();
375 #else
376 		panic("VFP exception in userland");
377 #endif
378 		break;
379 	case EXCP_SVC:
380 		svc_handler(frame);
381 		break;
382 	case EXCP_INSN_ABORT_L:
383 	case EXCP_DATA_ABORT_L:
384 	case EXCP_DATA_ABORT:
385 		data_abort(frame, esr, far, 1);
386 		break;
387 	case EXCP_UNKNOWN:
388 		el0_excp_unknown(frame, far);
389 		break;
390 	case EXCP_SP_ALIGN:
391 		call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_sp);
392 		userret(td, frame);
393 		break;
394 	case EXCP_PC_ALIGN:
395 		call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_elr);
396 		userret(td, frame);
397 		break;
398 	case EXCP_BRK:
399 		call_trapsignal(td, SIGTRAP, TRAP_BRKPT, (void *)frame->tf_elr);
400 		userret(td, frame);
401 		break;
402 	case EXCP_MSR:
403 		call_trapsignal(td, SIGILL, ILL_PRVOPC, (void *)frame->tf_elr);
404 		userret(td, frame);
405 		break;
406 	case EXCP_SOFTSTP_EL0:
407 		td->td_frame->tf_spsr &= ~PSR_SS;
408 		td->td_pcb->pcb_flags &= ~PCB_SINGLE_STEP;
409 		WRITE_SPECIALREG(MDSCR_EL1,
410 		    READ_SPECIALREG(MDSCR_EL1) & ~DBG_MDSCR_SS);
411 		call_trapsignal(td, SIGTRAP, TRAP_TRACE,
412 		    (void *)frame->tf_elr);
413 		userret(td, frame);
414 		break;
415 	default:
416 		call_trapsignal(td, SIGBUS, BUS_OBJERR, (void *)frame->tf_elr);
417 		userret(td, frame);
418 		break;
419 	}
420 
421 	KASSERT((curthread->td_pcb->pcb_fpflags & ~PCB_FP_USERMASK) == 0,
422 	    ("Kernel VFP flags set while entering userspace"));
423 	KASSERT(
424 	    curthread->td_pcb->pcb_fpusaved == &curthread->td_pcb->pcb_fpustate,
425 	    ("Kernel VFP state in use when entering userspace"));
426 }
427 
428 void
429 do_el0_error(struct trapframe *frame)
430 {
431 
432 	panic("ARM64TODO: do_el0_error");
433 }
434 
435