2 * Copyright (c) 2014 Andrew Turner
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
30 #include <sys/param.h>
31 #include <sys/systm.h>
33 #include <sys/kernel.h>
37 #include <sys/mutex.h>
39 #include <sys/ptrace.h>
40 #include <sys/syscall.h>
41 #include <sys/sysent.h>
48 #include <vm/vm_kern.h>
49 #include <vm/vm_map.h>
50 #include <vm/vm_param.h>
51 #include <vm/vm_extern.h>
53 #include <machine/frame.h>
54 #include <machine/md_var.h>
55 #include <machine/pcb.h>
56 #include <machine/pcpu.h>
57 #include <machine/undefined.h>
60 #include <sys/dtrace_bsd.h>
64 #include <machine/vfp.h>
68 #include <machine/db_machdep.h>
73 #include <ddb/db_sym.h>
76 /* Called from exception.S */
77 void do_el1h_sync(struct thread *, struct trapframe *);
78 void do_el0_sync(struct thread *, struct trapframe *);
79 void do_el0_error(struct trapframe *);
80 void do_serror(struct trapframe *);
81 void unhandled_exception(struct trapframe *);
83 static void print_gp_register(const char *name, uint64_t value);
84 static void print_registers(struct trapframe *frame);
86 int (*dtrace_invop_jump_addr)(struct trapframe *);
88 typedef void (abort_handler)(struct thread *, struct trapframe *, uint64_t,
91 static abort_handler align_abort;
92 static abort_handler data_abort;
93 static abort_handler external_abort;
95 static abort_handler *abort_handlers[] = {
96 [ISS_DATA_DFSC_TF_L0] = data_abort,
97 [ISS_DATA_DFSC_TF_L1] = data_abort,
98 [ISS_DATA_DFSC_TF_L2] = data_abort,
99 [ISS_DATA_DFSC_TF_L3] = data_abort,
100 [ISS_DATA_DFSC_AFF_L1] = data_abort,
101 [ISS_DATA_DFSC_AFF_L2] = data_abort,
102 [ISS_DATA_DFSC_AFF_L3] = data_abort,
103 [ISS_DATA_DFSC_PF_L1] = data_abort,
104 [ISS_DATA_DFSC_PF_L2] = data_abort,
105 [ISS_DATA_DFSC_PF_L3] = data_abort,
106 [ISS_DATA_DFSC_ALIGN] = align_abort,
107 [ISS_DATA_DFSC_EXT] = external_abort,
108 [ISS_DATA_DFSC_EXT_L0] = external_abort,
109 [ISS_DATA_DFSC_EXT_L1] = external_abort,
110 [ISS_DATA_DFSC_EXT_L2] = external_abort,
111 [ISS_DATA_DFSC_EXT_L3] = external_abort,
112 [ISS_DATA_DFSC_ECC] = external_abort,
113 [ISS_DATA_DFSC_ECC_L0] = external_abort,
114 [ISS_DATA_DFSC_ECC_L1] = external_abort,
115 [ISS_DATA_DFSC_ECC_L2] = external_abort,
116 [ISS_DATA_DFSC_ECC_L3] = external_abort,
120 call_trapsignal(struct thread *td, int sig, int code, void *addr, int trapno)
124 ksiginfo_init_trap(&ksi);
128 ksi.ksi_trapno = trapno;
129 trapsignal(td, &ksi);
133 cpu_fetch_syscall_args(struct thread *td)
136 syscallarg_t *ap, *dst_ap;
137 struct syscall_args *sa;
141 ap = td->td_frame->tf_x;
142 dst_ap = &sa->args[0];
144 sa->code = td->td_frame->tf_x[8];
145 sa->original_code = sa->code;
147 if (__predict_false(sa->code == SYS_syscall || sa->code == SYS___syscall)) {
153 if (__predict_false(sa->code >= p->p_sysent->sv_size))
154 sa->callp = &nosys_sysent;
156 sa->callp = &p->p_sysent->sv_table[sa->code];
158 KASSERT(sa->callp->sy_narg <= nitems(sa->args),
159 ("Syscall %d takes too many arguments", sa->code));
161 memcpy(dst_ap, ap, (nitems(sa->args) - 1) * sizeof(*dst_ap));
163 td->td_retval[0] = 0;
164 td->td_retval[1] = 0;
169 #include "../../kern/subr_syscall.c"
172 * Test for fault generated by given access instruction in
173 * bus_peek_<foo> or bus_poke_<foo> bus function.
175 extern uint32_t generic_bs_peek_1f, generic_bs_peek_2f;
176 extern uint32_t generic_bs_peek_4f, generic_bs_peek_8f;
177 extern uint32_t generic_bs_poke_1f, generic_bs_poke_2f;
178 extern uint32_t generic_bs_poke_4f, generic_bs_poke_8f;
181 test_bs_fault(void *addr)
183 return (addr == &generic_bs_peek_1f ||
184 addr == &generic_bs_peek_2f ||
185 addr == &generic_bs_peek_4f ||
186 addr == &generic_bs_peek_8f ||
187 addr == &generic_bs_poke_1f ||
188 addr == &generic_bs_poke_2f ||
189 addr == &generic_bs_poke_4f ||
190 addr == &generic_bs_poke_8f);
194 svc_handler(struct thread *td, struct trapframe *frame)
197 if ((frame->tf_esr & ESR_ELx_ISS_MASK) == 0) {
201 call_trapsignal(td, SIGILL, ILL_ILLOPN, (void *)frame->tf_elr,
202 ESR_ELx_EXCEPTION(frame->tf_esr));
208 align_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
209 uint64_t far, int lower)
212 print_registers(frame);
213 print_gp_register("far", far);
214 printf(" esr: 0x%.16lx\n", esr);
215 panic("Misaligned access from kernel space!");
218 call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_elr,
219 ESR_ELx_EXCEPTION(frame->tf_esr));
225 external_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
226 uint64_t far, int lower)
229 call_trapsignal(td, SIGBUS, BUS_OBJERR, (void *)far,
230 ESR_ELx_EXCEPTION(frame->tf_esr));
236 * Try to handle synchronous external aborts caused by
237 * bus_space_peek() and/or bus_space_poke() functions.
239 if (test_bs_fault((void *)frame->tf_elr)) {
240 frame->tf_elr = (uint64_t)generic_bs_fault;
244 print_registers(frame);
245 print_gp_register("far", far);
246 panic("Unhandled external data abort");
250 * It is unsafe to access the stack canary value stored in "td" until
251 * kernel map translation faults are handled, see the pmap_klookup() call below.
252 * Thus, stack-smashing detection with per-thread canaries must be disabled in
255 static void NO_PERTHREAD_SSP
256 data_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
257 uint64_t far, int lower)
262 int error, sig, ucode;
268 * According to the ARMv8-A rev. A.g, B2.10.5 "Load-Exclusive
269 * and Store-Exclusive instruction usage restrictions", state
270 * of the exclusive monitors after data abort exception is unknown.
282 map = &td->td_proc->p_vmspace->vm_map;
283 } else if (!ADDR_IS_CANONICAL(far)) {
284 /* We received a TBI/PAC/etc. fault from the kernel */
285 error = KERN_INVALID_ADDRESS;
288 } else if (ADDR_IS_KERNEL(far)) {
290 * Handle a special case: the data abort was caused by accessing
291 * a thread structure while its mapping was being promoted or
292 * demoted, as a consequence of the break-before-make rule. It
293 * is not safe to enable interrupts or dereference "td" before
294 * this case is handled.
296 * In principle, if pmap_klookup() fails, there is no need to
297 * call pmap_fault() below, but avoiding that call is not worth
300 if (ESR_ELx_EXCEPTION(esr) == EXCP_DATA_ABORT) {
301 switch (esr & ISS_DATA_DFSC_MASK) {
302 case ISS_DATA_DFSC_TF_L0:
303 case ISS_DATA_DFSC_TF_L1:
304 case ISS_DATA_DFSC_TF_L2:
305 case ISS_DATA_DFSC_TF_L3:
306 if (pmap_klookup(far, NULL))
315 map = &td->td_proc->p_vmspace->vm_map;
322 * Try to handle translation, access flag, and permission faults.
323 * Translation faults may occur as a result of the required
324 * break-before-make sequence used when promoting or demoting
325 * superpages. Such faults must not occur while holding the pmap lock,
326 * or pmap_fault() will recurse on that lock.
328 if ((lower || map == kernel_map || pcb->pcb_onfault != 0) &&
329 pmap_fault(map->pmap, esr, far) == KERN_SUCCESS)
333 if (td->td_md.md_spinlock_count != 0) {
334 print_registers(frame);
335 print_gp_register("far", far);
336 printf(" esr: 0x%.16lx\n", esr);
337 panic("data abort with spinlock held (spinlock count %d != 0)",
338 td->td_md.md_spinlock_count);
341 if (td->td_critnest != 0 || WITNESS_CHECK(WARN_SLEEPOK |
342 WARN_GIANTOK, NULL, "Kernel page fault") != 0) {
343 print_registers(frame);
344 print_gp_register("far", far);
345 printf(" esr: 0x%.16lx\n", esr);
346 panic("data abort in critical section or under mutex");
349 switch (ESR_ELx_EXCEPTION(esr)) {
350 case EXCP_INSN_ABORT:
351 case EXCP_INSN_ABORT_L:
352 ftype = VM_PROT_EXECUTE;
356 * If the exception was because of a read or cache operation
357 * pass a read fault type into the vm code. Cache operations
358 * need read permission but will set the WnR flag when the
359 * memory is unmapped.
361 if ((esr & ISS_DATA_WnR) == 0 || (esr & ISS_DATA_CM) != 0)
362 ftype = VM_PROT_READ;
364 ftype = VM_PROT_WRITE;
368 /* Fault in the page. */
369 error = vm_fault_trap(map, far, ftype, VM_FAULT_NORMAL, &sig, &ucode);
370 if (error != KERN_SUCCESS) {
372 call_trapsignal(td, sig, ucode, (void *)far,
373 ESR_ELx_EXCEPTION(esr));
376 if (td->td_intr_nesting_level == 0 &&
377 pcb->pcb_onfault != 0) {
378 frame->tf_x[0] = error;
379 frame->tf_elr = pcb->pcb_onfault;
383 printf("Fatal data abort:\n");
384 print_registers(frame);
385 print_gp_register("far", far);
386 printf(" esr: 0x%.16lx\n", esr);
389 if (debugger_on_trap) {
390 kdb_why = KDB_WHY_TRAP;
391 handled = kdb_trap(ESR_ELx_EXCEPTION(esr), 0,
393 kdb_why = KDB_WHY_UNSET;
398 panic("vm_fault failed: 0x%lx error %d",
399 frame->tf_elr, error);
408 print_gp_register(const char *name, uint64_t value)
412 const char *sym_name;
417 printf(" %s: 0x%.16lx", name, value);
419 /* If this looks like a kernel address try to find the symbol */
420 if (value >= VM_MIN_KERNEL_ADDRESS) {
421 sym = db_search_symbol(value, DB_STGY_ANY, &offset);
422 if (sym != C_DB_SYM_NULL) {
423 db_symbol_values(sym, &sym_name, &sym_value);
424 printf(" (%s + 0x%lx)", sym_name, offset);
432 print_registers(struct trapframe *frame)
437 for (reg = 0; reg < nitems(frame->tf_x); reg++) {
438 snprintf(name, sizeof(name), "%sx%d", (reg < 10) ? " " : "",
440 print_gp_register(name, frame->tf_x[reg]);
442 printf(" sp: 0x%.16lx\n", frame->tf_sp);
443 print_gp_register(" lr", frame->tf_lr);
444 print_gp_register("elr", frame->tf_elr);
445 printf("spsr: 0x%.16lx\n", frame->tf_spsr);
450 fpe_trap(struct thread *td, void *addr, uint32_t exception)
455 if ((exception & ISS_FP_TFV) != 0) {
456 if ((exception & ISS_FP_IOF) != 0)
458 else if ((exception & ISS_FP_DZF) != 0)
460 else if ((exception & ISS_FP_OFF) != 0)
462 else if ((exception & ISS_FP_UFF) != 0)
464 else if ((exception & ISS_FP_IXF) != 0)
467 call_trapsignal(td, SIGFPE, code, addr, exception);
472 * See the comment above data_abort().
474 void NO_PERTHREAD_SSP
475 do_el1h_sync(struct thread *td, struct trapframe *frame)
481 kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0);
482 kmsan_mark(frame, sizeof(*frame), KMSAN_STATE_INITED);
485 /* Read the esr register to get the exception details */
487 exception = ESR_ELx_EXCEPTION(esr);
490 if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, exception))
494 CTR4(KTR_TRAP, "%s: exception=%lu, elr=0x%lx, esr=0x%lx",
495 __func__, exception, frame->tf_elr, esr);
498 * Enable debug exceptions if we aren't already handling one. They will
499 * be masked again in the exception handler's epilogue.
501 if (exception != EXCP_BRK && exception != EXCP_WATCHPT_EL1 &&
502 exception != EXCP_SOFTSTP_EL1)
509 if ((td->td_pcb->pcb_fpflags & PCB_FP_KERN) != 0) {
514 print_registers(frame);
515 printf(" esr: 0x%.16lx\n", esr);
516 panic("VFP exception in the kernel");
519 case EXCP_INSN_ABORT:
520 case EXCP_DATA_ABORT:
521 dfsc = esr & ISS_DATA_DFSC_MASK;
522 if (dfsc < nitems(abort_handlers) &&
523 abort_handlers[dfsc] != NULL) {
524 abort_handlers[dfsc](td, frame, esr, far, 0);
526 print_registers(frame);
527 print_gp_register("far", far);
528 printf(" esr: 0x%.16lx\n", esr);
529 panic("Unhandled EL1 %s abort: 0x%x",
530 exception == EXCP_INSN_ABORT ? "instruction" :
536 if ((esr & ESR_ELx_ISS_MASK) == 0x40d && \
537 dtrace_invop_jump_addr != 0) {
538 dtrace_invop_jump_addr(frame);
543 kdb_trap(exception, 0, frame);
545 panic("No debugger in kernel.");
548 case EXCP_WATCHPT_EL1:
549 case EXCP_SOFTSTP_EL1:
551 kdb_trap(exception, 0, frame);
553 panic("No debugger in kernel.");
557 /* We can see this if the authentication on PAC fails */
558 print_registers(frame);
559 print_gp_register("far", far);
560 panic("FPAC kernel exception");
563 if (undef_insn(1, frame))
565 print_registers(frame);
566 print_gp_register("far", far);
567 panic("Undefined instruction: %08x",
568 *(uint32_t *)frame->tf_elr);
571 print_registers(frame);
572 print_gp_register("far", far);
573 panic("Branch Target exception");
576 print_registers(frame);
577 print_gp_register("far", far);
578 panic("Unknown kernel exception 0x%x esr_el1 0x%lx", exception,
584 do_el0_sync(struct thread *td, struct trapframe *frame)
586 pcpu_bp_harden bp_harden;
591 /* Check we have a sane environment when entering from userland */
592 KASSERT((uintptr_t)get_pcpu() >= VM_MIN_KERNEL_ADDRESS,
593 ("Invalid pcpu address from userland: %p (tpidr 0x%lx)",
594 get_pcpu(), READ_SPECIALREG(tpidr_el1)));
596 kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0);
597 kmsan_mark(frame, sizeof(*frame), KMSAN_STATE_INITED);
601 exception = ESR_ELx_EXCEPTION(esr);
602 if (exception == EXCP_INSN_ABORT_L && far > VM_MAXUSER_ADDRESS) {
604 * Userspace may be trying to train the branch predictor to
605 * attack the kernel. If we are on a CPU affected by this
606 * call the handler to clear the branch predictor state.
608 bp_harden = PCPU_GET(bp_harden);
609 if (bp_harden != NULL)
614 CTR4(KTR_TRAP, "%s: exception=%lu, elr=0x%lx, esr=0x%lx",
615 __func__, exception, frame->tf_elr, esr);
622 panic("VFP exception in userland");
627 fpe_trap(td, (void *)frame->tf_elr, esr);
630 panic("VFP exception in userland");
634 call_trapsignal(td, SIGILL, ILL_ILLTRP, (void *)frame->tf_elr,
640 svc_handler(td, frame);
642 case EXCP_INSN_ABORT_L:
643 case EXCP_DATA_ABORT_L:
644 case EXCP_DATA_ABORT:
645 dfsc = esr & ISS_DATA_DFSC_MASK;
646 if (dfsc < nitems(abort_handlers) &&
647 abort_handlers[dfsc] != NULL)
648 abort_handlers[dfsc](td, frame, esr, far, 1);
650 print_registers(frame);
651 print_gp_register("far", far);
652 printf(" esr: 0x%.16lx\n", esr);
653 panic("Unhandled EL0 %s abort: 0x%x",
654 exception == EXCP_INSN_ABORT_L ? "instruction" :
659 if (!undef_insn(0, frame))
660 call_trapsignal(td, SIGILL, ILL_ILLTRP, (void *)far,
665 call_trapsignal(td, SIGILL, ILL_ILLOPN, (void *)frame->tf_elr,
670 call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_sp,
675 call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_elr,
681 #ifdef COMPAT_FREEBSD32
683 #endif /* COMPAT_FREEBSD32 */
684 call_trapsignal(td, SIGTRAP, TRAP_BRKPT, (void *)frame->tf_elr,
688 case EXCP_WATCHPT_EL0:
689 call_trapsignal(td, SIGTRAP, TRAP_TRACE, (void *)far,
695 * The CPU can raise EXCP_MSR when userspace executes an mrs
696 * instruction to access a special register userspace doesn't
699 if (!undef_insn(0, frame))
700 call_trapsignal(td, SIGILL, ILL_PRVOPC,
701 (void *)frame->tf_elr, exception);
704 case EXCP_SOFTSTP_EL0:
705 PROC_LOCK(td->td_proc);
706 if ((td->td_dbgflags & TDB_STEP) != 0) {
707 td->td_frame->tf_spsr &= ~PSR_SS;
708 td->td_pcb->pcb_flags &= ~PCB_SINGLE_STEP;
709 WRITE_SPECIALREG(mdscr_el1,
710 READ_SPECIALREG(mdscr_el1) & ~MDSCR_SS);
712 PROC_UNLOCK(td->td_proc);
713 call_trapsignal(td, SIGTRAP, TRAP_TRACE,
714 (void *)frame->tf_elr, exception);
718 call_trapsignal(td, SIGILL, ILL_ILLOPC, (void *)frame->tf_elr,
723 call_trapsignal(td, SIGBUS, BUS_OBJERR, (void *)frame->tf_elr,
729 KASSERT((td->td_pcb->pcb_fpflags & ~PCB_FP_USERMASK) == 0,
730 ("Kernel VFP flags set while entering userspace"));
732 td->td_pcb->pcb_fpusaved == &td->td_pcb->pcb_fpustate,
733 ("Kernel VFP state in use when entering userspace"));
737 * TODO: We will need to handle these later when we support ARMv8.2 RAS.
740 do_serror(struct trapframe *frame)
744 kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0);
745 kmsan_mark(frame, sizeof(*frame), KMSAN_STATE_INITED);
750 print_registers(frame);
751 print_gp_register("far", far);
752 printf(" esr: 0x%.16lx\n", esr);
753 panic("Unhandled System Error");
757 unhandled_exception(struct trapframe *frame)
761 kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0);
762 kmsan_mark(frame, sizeof(*frame), KMSAN_STATE_INITED);
767 print_registers(frame);
768 print_gp_register("far", far);
769 printf(" esr: 0x%.16lx\n", esr);
770 panic("Unhandled exception");