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>
36 #include <sys/mutex.h>
38 #include <sys/ptrace.h>
39 #include <sys/syscall.h>
40 #include <sys/sysent.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>
52 #include <machine/frame.h>
53 #include <machine/md_var.h>
54 #include <machine/pcb.h>
55 #include <machine/pcpu.h>
56 #include <machine/undefined.h>
59 #include <sys/dtrace_bsd.h>
63 #include <machine/vfp.h>
67 #include <machine/db_machdep.h>
72 #include <ddb/db_sym.h>
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 void do_serror(struct trapframe *);
80 void unhandled_exception(struct trapframe *);
82 static void print_gp_register(const char *name, uint64_t value);
83 static void print_registers(struct trapframe *frame);
85 int (*dtrace_invop_jump_addr)(struct trapframe *);
87 typedef void (abort_handler)(struct thread *, struct trapframe *, uint64_t,
90 static abort_handler align_abort;
91 static abort_handler data_abort;
92 static abort_handler external_abort;
94 static abort_handler *abort_handlers[] = {
95 [ISS_DATA_DFSC_TF_L0] = data_abort,
96 [ISS_DATA_DFSC_TF_L1] = data_abort,
97 [ISS_DATA_DFSC_TF_L2] = data_abort,
98 [ISS_DATA_DFSC_TF_L3] = data_abort,
99 [ISS_DATA_DFSC_AFF_L1] = data_abort,
100 [ISS_DATA_DFSC_AFF_L2] = data_abort,
101 [ISS_DATA_DFSC_AFF_L3] = data_abort,
102 [ISS_DATA_DFSC_PF_L1] = data_abort,
103 [ISS_DATA_DFSC_PF_L2] = data_abort,
104 [ISS_DATA_DFSC_PF_L3] = data_abort,
105 [ISS_DATA_DFSC_ALIGN] = align_abort,
106 [ISS_DATA_DFSC_EXT] = external_abort,
107 [ISS_DATA_DFSC_EXT_L0] = external_abort,
108 [ISS_DATA_DFSC_EXT_L1] = external_abort,
109 [ISS_DATA_DFSC_EXT_L2] = external_abort,
110 [ISS_DATA_DFSC_EXT_L3] = external_abort,
111 [ISS_DATA_DFSC_ECC] = external_abort,
112 [ISS_DATA_DFSC_ECC_L0] = external_abort,
113 [ISS_DATA_DFSC_ECC_L1] = external_abort,
114 [ISS_DATA_DFSC_ECC_L2] = external_abort,
115 [ISS_DATA_DFSC_ECC_L3] = external_abort,
119 call_trapsignal(struct thread *td, int sig, int code, void *addr, int trapno)
123 ksiginfo_init_trap(&ksi);
127 ksi.ksi_trapno = trapno;
128 trapsignal(td, &ksi);
132 cpu_fetch_syscall_args(struct thread *td)
135 syscallarg_t *ap, *dst_ap;
136 struct syscall_args *sa;
140 ap = td->td_frame->tf_x;
141 dst_ap = &sa->args[0];
143 sa->code = td->td_frame->tf_x[8];
144 sa->original_code = sa->code;
146 if (__predict_false(sa->code == SYS_syscall || sa->code == SYS___syscall)) {
152 if (__predict_false(sa->code >= p->p_sysent->sv_size))
153 sa->callp = &nosys_sysent;
155 sa->callp = &p->p_sysent->sv_table[sa->code];
157 KASSERT(sa->callp->sy_narg <= nitems(sa->args),
158 ("Syscall %d takes too many arguments", sa->code));
160 memcpy(dst_ap, ap, (nitems(sa->args) - 1) * sizeof(*dst_ap));
162 td->td_retval[0] = 0;
163 td->td_retval[1] = 0;
168 #include "../../kern/subr_syscall.c"
171 * Test for fault generated by given access instruction in
172 * bus_peek_<foo> or bus_poke_<foo> bus function.
174 extern uint32_t generic_bs_peek_1f, generic_bs_peek_2f;
175 extern uint32_t generic_bs_peek_4f, generic_bs_peek_8f;
176 extern uint32_t generic_bs_poke_1f, generic_bs_poke_2f;
177 extern uint32_t generic_bs_poke_4f, generic_bs_poke_8f;
180 test_bs_fault(void *addr)
182 return (addr == &generic_bs_peek_1f ||
183 addr == &generic_bs_peek_2f ||
184 addr == &generic_bs_peek_4f ||
185 addr == &generic_bs_peek_8f ||
186 addr == &generic_bs_poke_1f ||
187 addr == &generic_bs_poke_2f ||
188 addr == &generic_bs_poke_4f ||
189 addr == &generic_bs_poke_8f);
193 svc_handler(struct thread *td, struct trapframe *frame)
196 if ((frame->tf_esr & ESR_ELx_ISS_MASK) == 0) {
200 call_trapsignal(td, SIGILL, ILL_ILLOPN, (void *)frame->tf_elr,
201 ESR_ELx_EXCEPTION(frame->tf_esr));
207 align_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
208 uint64_t far, int lower)
211 print_registers(frame);
212 print_gp_register("far", far);
213 printf(" esr: 0x%.16lx\n", esr);
214 panic("Misaligned access from kernel space!");
217 call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_elr,
218 ESR_ELx_EXCEPTION(frame->tf_esr));
224 external_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
225 uint64_t far, int lower)
228 call_trapsignal(td, SIGBUS, BUS_OBJERR, (void *)far,
229 ESR_ELx_EXCEPTION(frame->tf_esr));
235 * Try to handle synchronous external aborts caused by
236 * bus_space_peek() and/or bus_space_poke() functions.
238 if (test_bs_fault((void *)frame->tf_elr)) {
239 frame->tf_elr = (uint64_t)generic_bs_fault;
243 print_registers(frame);
244 print_gp_register("far", far);
245 panic("Unhandled external data abort");
249 * It is unsafe to access the stack canary value stored in "td" until
250 * kernel map translation faults are handled, see the pmap_klookup() call below.
251 * Thus, stack-smashing detection with per-thread canaries must be disabled in
254 static void NO_PERTHREAD_SSP
255 data_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
256 uint64_t far, int lower)
261 int error, sig, ucode;
267 * According to the ARMv8-A rev. A.g, B2.10.5 "Load-Exclusive
268 * and Store-Exclusive instruction usage restrictions", state
269 * of the exclusive monitors after data abort exception is unknown.
281 map = &td->td_proc->p_vmspace->vm_map;
282 } else if (!ADDR_IS_CANONICAL(far)) {
283 /* We received a TBI/PAC/etc. fault from the kernel */
284 error = KERN_INVALID_ADDRESS;
287 } else if (ADDR_IS_KERNEL(far)) {
289 * Handle a special case: the data abort was caused by accessing
290 * a thread structure while its mapping was being promoted or
291 * demoted, as a consequence of the break-before-make rule. It
292 * is not safe to enable interrupts or dereference "td" before
293 * this case is handled.
295 * In principle, if pmap_klookup() fails, there is no need to
296 * call pmap_fault() below, but avoiding that call is not worth
299 if (ESR_ELx_EXCEPTION(esr) == EXCP_DATA_ABORT) {
300 switch (esr & ISS_DATA_DFSC_MASK) {
301 case ISS_DATA_DFSC_TF_L0:
302 case ISS_DATA_DFSC_TF_L1:
303 case ISS_DATA_DFSC_TF_L2:
304 case ISS_DATA_DFSC_TF_L3:
305 if (pmap_klookup(far, NULL))
314 map = &td->td_proc->p_vmspace->vm_map;
321 * Try to handle translation, access flag, and permission faults.
322 * Translation faults may occur as a result of the required
323 * break-before-make sequence used when promoting or demoting
324 * superpages. Such faults must not occur while holding the pmap lock,
325 * or pmap_fault() will recurse on that lock.
327 if ((lower || map == kernel_map || pcb->pcb_onfault != 0) &&
328 pmap_fault(map->pmap, esr, far) == KERN_SUCCESS)
332 if (td->td_md.md_spinlock_count != 0) {
333 print_registers(frame);
334 print_gp_register("far", far);
335 printf(" esr: 0x%.16lx\n", esr);
336 panic("data abort with spinlock held (spinlock count %d != 0)",
337 td->td_md.md_spinlock_count);
340 if (td->td_critnest != 0 || WITNESS_CHECK(WARN_SLEEPOK |
341 WARN_GIANTOK, NULL, "Kernel page fault") != 0) {
342 print_registers(frame);
343 print_gp_register("far", far);
344 printf(" esr: 0x%.16lx\n", esr);
345 panic("data abort in critical section or under mutex");
348 switch (ESR_ELx_EXCEPTION(esr)) {
349 case EXCP_INSN_ABORT:
350 case EXCP_INSN_ABORT_L:
351 ftype = VM_PROT_EXECUTE;
355 * If the exception was because of a read or cache operation
356 * pass a read fault type into the vm code. Cache operations
357 * need read permission but will set the WnR flag when the
358 * memory is unmapped.
360 if ((esr & ISS_DATA_WnR) == 0 || (esr & ISS_DATA_CM) != 0)
361 ftype = VM_PROT_READ;
363 ftype = VM_PROT_WRITE;
367 /* Fault in the page. */
368 error = vm_fault_trap(map, far, ftype, VM_FAULT_NORMAL, &sig, &ucode);
369 if (error != KERN_SUCCESS) {
371 call_trapsignal(td, sig, ucode, (void *)far,
372 ESR_ELx_EXCEPTION(esr));
375 if (td->td_intr_nesting_level == 0 &&
376 pcb->pcb_onfault != 0) {
377 frame->tf_x[0] = error;
378 frame->tf_elr = pcb->pcb_onfault;
382 printf("Fatal data abort:\n");
383 print_registers(frame);
384 print_gp_register("far", far);
385 printf(" esr: 0x%.16lx\n", esr);
388 if (debugger_on_trap) {
389 kdb_why = KDB_WHY_TRAP;
390 handled = kdb_trap(ESR_ELx_EXCEPTION(esr), 0,
392 kdb_why = KDB_WHY_UNSET;
397 panic("vm_fault failed: 0x%lx error %d",
398 frame->tf_elr, error);
407 print_gp_register(const char *name, uint64_t value)
411 const char *sym_name;
416 printf(" %s: 0x%.16lx", name, value);
418 /* If this looks like a kernel address try to find the symbol */
419 if (value >= VM_MIN_KERNEL_ADDRESS) {
420 sym = db_search_symbol(value, DB_STGY_ANY, &offset);
421 if (sym != C_DB_SYM_NULL) {
422 db_symbol_values(sym, &sym_name, &sym_value);
423 printf(" (%s + 0x%lx)", sym_name, offset);
431 print_registers(struct trapframe *frame)
436 for (reg = 0; reg < nitems(frame->tf_x); reg++) {
437 snprintf(name, sizeof(name), "%sx%d", (reg < 10) ? " " : "",
439 print_gp_register(name, frame->tf_x[reg]);
441 printf(" sp: 0x%.16lx\n", frame->tf_sp);
442 print_gp_register(" lr", frame->tf_lr);
443 print_gp_register("elr", frame->tf_elr);
444 printf("spsr: 0x%.16lx\n", frame->tf_spsr);
449 fpe_trap(struct thread *td, void *addr, uint32_t exception)
454 if ((exception & ISS_FP_TFV) != 0) {
455 if ((exception & ISS_FP_IOF) != 0)
457 else if ((exception & ISS_FP_DZF) != 0)
459 else if ((exception & ISS_FP_OFF) != 0)
461 else if ((exception & ISS_FP_UFF) != 0)
463 else if ((exception & ISS_FP_IXF) != 0)
466 call_trapsignal(td, SIGFPE, code, addr, exception);
471 * See the comment above data_abort().
473 void NO_PERTHREAD_SSP
474 do_el1h_sync(struct thread *td, struct trapframe *frame)
480 kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0);
482 /* Read the esr register to get the exception details */
484 exception = ESR_ELx_EXCEPTION(esr);
487 if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, exception))
491 CTR4(KTR_TRAP, "%s: exception=%lu, elr=0x%lx, esr=0x%lx",
492 __func__, exception, frame->tf_elr, esr);
495 * Enable debug exceptions if we aren't already handling one. They will
496 * be masked again in the exception handler's epilogue.
498 if (exception != EXCP_BRK && exception != EXCP_WATCHPT_EL1 &&
499 exception != EXCP_SOFTSTP_EL1)
506 if ((td->td_pcb->pcb_fpflags & PCB_FP_KERN) != 0) {
511 print_registers(frame);
512 printf(" esr: 0x%.16lx\n", esr);
513 panic("VFP exception in the kernel");
516 case EXCP_INSN_ABORT:
517 case EXCP_DATA_ABORT:
518 dfsc = esr & ISS_DATA_DFSC_MASK;
519 if (dfsc < nitems(abort_handlers) &&
520 abort_handlers[dfsc] != NULL) {
521 abort_handlers[dfsc](td, frame, esr, far, 0);
523 print_registers(frame);
524 print_gp_register("far", far);
525 printf(" esr: 0x%.16lx\n", esr);
526 panic("Unhandled EL1 %s abort: 0x%x",
527 exception == EXCP_INSN_ABORT ? "instruction" :
533 if ((esr & ESR_ELx_ISS_MASK) == 0x40d && \
534 dtrace_invop_jump_addr != 0) {
535 dtrace_invop_jump_addr(frame);
540 kdb_trap(exception, 0, frame);
542 panic("No debugger in kernel.");
545 case EXCP_WATCHPT_EL1:
546 case EXCP_SOFTSTP_EL1:
548 kdb_trap(exception, 0, frame);
550 panic("No debugger in kernel.");
554 /* We can see this if the authentication on PAC fails */
555 print_registers(frame);
556 print_gp_register("far", far);
557 panic("FPAC kernel exception");
560 if (undef_insn(1, frame))
562 print_registers(frame);
563 print_gp_register("far", far);
564 panic("Undefined instruction: %08x",
565 *(uint32_t *)frame->tf_elr);
568 print_registers(frame);
569 print_gp_register("far", far);
570 panic("Branch Target exception");
573 print_registers(frame);
574 print_gp_register("far", far);
575 panic("Unknown kernel exception 0x%x esr_el1 0x%lx", exception,
581 do_el0_sync(struct thread *td, struct trapframe *frame)
583 pcpu_bp_harden bp_harden;
588 /* Check we have a sane environment when entering from userland */
589 KASSERT((uintptr_t)get_pcpu() >= VM_MIN_KERNEL_ADDRESS,
590 ("Invalid pcpu address from userland: %p (tpidr 0x%lx)",
591 get_pcpu(), READ_SPECIALREG(tpidr_el1)));
593 kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0);
596 exception = ESR_ELx_EXCEPTION(esr);
597 if (exception == EXCP_INSN_ABORT_L && far > VM_MAXUSER_ADDRESS) {
599 * Userspace may be trying to train the branch predictor to
600 * attack the kernel. If we are on a CPU affected by this
601 * call the handler to clear the branch predictor state.
603 bp_harden = PCPU_GET(bp_harden);
604 if (bp_harden != NULL)
609 CTR4(KTR_TRAP, "%s: exception=%lu, elr=0x%lx, esr=0x%lx",
610 __func__, exception, frame->tf_elr, esr);
617 panic("VFP exception in userland");
622 fpe_trap(td, (void *)frame->tf_elr, esr);
625 panic("VFP exception in userland");
629 call_trapsignal(td, SIGILL, ILL_ILLTRP, (void *)frame->tf_elr,
635 svc_handler(td, frame);
637 case EXCP_INSN_ABORT_L:
638 case EXCP_DATA_ABORT_L:
639 case EXCP_DATA_ABORT:
640 dfsc = esr & ISS_DATA_DFSC_MASK;
641 if (dfsc < nitems(abort_handlers) &&
642 abort_handlers[dfsc] != NULL)
643 abort_handlers[dfsc](td, frame, esr, far, 1);
645 print_registers(frame);
646 print_gp_register("far", far);
647 printf(" esr: 0x%.16lx\n", esr);
648 panic("Unhandled EL0 %s abort: 0x%x",
649 exception == EXCP_INSN_ABORT_L ? "instruction" :
654 if (!undef_insn(0, frame))
655 call_trapsignal(td, SIGILL, ILL_ILLTRP, (void *)far,
660 call_trapsignal(td, SIGILL, ILL_ILLOPN, (void *)frame->tf_elr,
665 call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_sp,
670 call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_elr,
676 #ifdef COMPAT_FREEBSD32
678 #endif /* COMPAT_FREEBSD32 */
679 call_trapsignal(td, SIGTRAP, TRAP_BRKPT, (void *)frame->tf_elr,
683 case EXCP_WATCHPT_EL0:
684 call_trapsignal(td, SIGTRAP, TRAP_TRACE, (void *)far,
690 * The CPU can raise EXCP_MSR when userspace executes an mrs
691 * instruction to access a special register userspace doesn't
694 if (!undef_insn(0, frame))
695 call_trapsignal(td, SIGILL, ILL_PRVOPC,
696 (void *)frame->tf_elr, exception);
699 case EXCP_SOFTSTP_EL0:
700 PROC_LOCK(td->td_proc);
701 if ((td->td_dbgflags & TDB_STEP) != 0) {
702 td->td_frame->tf_spsr &= ~PSR_SS;
703 td->td_pcb->pcb_flags &= ~PCB_SINGLE_STEP;
704 WRITE_SPECIALREG(mdscr_el1,
705 READ_SPECIALREG(mdscr_el1) & ~MDSCR_SS);
707 PROC_UNLOCK(td->td_proc);
708 call_trapsignal(td, SIGTRAP, TRAP_TRACE,
709 (void *)frame->tf_elr, exception);
713 call_trapsignal(td, SIGILL, ILL_ILLOPC, (void *)frame->tf_elr,
718 call_trapsignal(td, SIGBUS, BUS_OBJERR, (void *)frame->tf_elr,
724 KASSERT((td->td_pcb->pcb_fpflags & ~PCB_FP_USERMASK) == 0,
725 ("Kernel VFP flags set while entering userspace"));
727 td->td_pcb->pcb_fpusaved == &td->td_pcb->pcb_fpustate,
728 ("Kernel VFP state in use when entering userspace"));
732 * TODO: We will need to handle these later when we support ARMv8.2 RAS.
735 do_serror(struct trapframe *frame)
739 kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0);
743 print_registers(frame);
744 print_gp_register("far", far);
745 printf(" esr: 0x%.16lx\n", esr);
746 panic("Unhandled System Error");
750 unhandled_exception(struct trapframe *frame)
754 kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0);
758 print_registers(frame);
759 print_gp_register("far", far);
760 printf(" esr: 0x%.16lx\n", esr);
761 panic("Unhandled exception");