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/cdefs.h>
31 __FBSDID("$FreeBSD$");
33 #include <sys/param.h>
34 #include <sys/systm.h>
36 #include <sys/kernel.h>
39 #include <sys/mutex.h>
41 #include <sys/ptrace.h>
42 #include <sys/syscall.h>
43 #include <sys/sysent.h>
50 #include <vm/vm_kern.h>
51 #include <vm/vm_map.h>
52 #include <vm/vm_param.h>
53 #include <vm/vm_extern.h>
55 #include <machine/frame.h>
56 #include <machine/md_var.h>
57 #include <machine/pcb.h>
58 #include <machine/pcpu.h>
59 #include <machine/undefined.h>
62 #include <sys/dtrace_bsd.h>
66 #include <machine/vfp.h>
70 #include <machine/db_machdep.h>
75 #include <ddb/db_sym.h>
78 /* Called from exception.S */
79 void do_el1h_sync(struct thread *, struct trapframe *);
80 void do_el0_sync(struct thread *, struct trapframe *);
81 void do_el0_error(struct trapframe *);
82 void do_serror(struct trapframe *);
83 void unhandled_exception(struct trapframe *);
85 static void print_gp_register(const char *name, uint64_t value);
86 static void print_registers(struct trapframe *frame);
88 int (*dtrace_invop_jump_addr)(struct trapframe *);
90 typedef void (abort_handler)(struct thread *, struct trapframe *, uint64_t,
93 static abort_handler align_abort;
94 static abort_handler data_abort;
95 static abort_handler external_abort;
97 static abort_handler *abort_handlers[] = {
98 [ISS_DATA_DFSC_TF_L0] = data_abort,
99 [ISS_DATA_DFSC_TF_L1] = data_abort,
100 [ISS_DATA_DFSC_TF_L2] = data_abort,
101 [ISS_DATA_DFSC_TF_L3] = data_abort,
102 [ISS_DATA_DFSC_AFF_L1] = data_abort,
103 [ISS_DATA_DFSC_AFF_L2] = data_abort,
104 [ISS_DATA_DFSC_AFF_L3] = data_abort,
105 [ISS_DATA_DFSC_PF_L1] = data_abort,
106 [ISS_DATA_DFSC_PF_L2] = data_abort,
107 [ISS_DATA_DFSC_PF_L3] = data_abort,
108 [ISS_DATA_DFSC_ALIGN] = align_abort,
109 [ISS_DATA_DFSC_EXT] = external_abort,
110 [ISS_DATA_DFSC_EXT_L0] = external_abort,
111 [ISS_DATA_DFSC_EXT_L1] = external_abort,
112 [ISS_DATA_DFSC_EXT_L2] = external_abort,
113 [ISS_DATA_DFSC_EXT_L3] = external_abort,
114 [ISS_DATA_DFSC_ECC] = external_abort,
115 [ISS_DATA_DFSC_ECC_L0] = external_abort,
116 [ISS_DATA_DFSC_ECC_L1] = external_abort,
117 [ISS_DATA_DFSC_ECC_L2] = external_abort,
118 [ISS_DATA_DFSC_ECC_L3] = external_abort,
122 call_trapsignal(struct thread *td, int sig, int code, void *addr, int trapno)
126 ksiginfo_init_trap(&ksi);
130 ksi.ksi_trapno = trapno;
131 trapsignal(td, &ksi);
135 cpu_fetch_syscall_args(struct thread *td)
138 syscallarg_t *ap, *dst_ap;
139 struct syscall_args *sa;
143 ap = td->td_frame->tf_x;
144 dst_ap = &sa->args[0];
146 sa->code = td->td_frame->tf_x[8];
147 sa->original_code = sa->code;
149 if (__predict_false(sa->code == SYS_syscall || sa->code == SYS___syscall)) {
155 if (__predict_false(sa->code >= p->p_sysent->sv_size))
156 sa->callp = &p->p_sysent->sv_table[0];
158 sa->callp = &p->p_sysent->sv_table[sa->code];
160 KASSERT(sa->callp->sy_narg <= nitems(sa->args),
161 ("Syscall %d takes too many arguments", sa->code));
163 memcpy(dst_ap, ap, (nitems(sa->args) - 1) * sizeof(*dst_ap));
165 td->td_retval[0] = 0;
166 td->td_retval[1] = 0;
171 #include "../../kern/subr_syscall.c"
174 * Test for fault generated by given access instruction in
175 * bus_peek_<foo> or bus_poke_<foo> bus function.
177 extern uint32_t generic_bs_peek_1f, generic_bs_peek_2f;
178 extern uint32_t generic_bs_peek_4f, generic_bs_peek_8f;
179 extern uint32_t generic_bs_poke_1f, generic_bs_poke_2f;
180 extern uint32_t generic_bs_poke_4f, generic_bs_poke_8f;
183 test_bs_fault(void *addr)
185 return (addr == &generic_bs_peek_1f ||
186 addr == &generic_bs_peek_2f ||
187 addr == &generic_bs_peek_4f ||
188 addr == &generic_bs_peek_8f ||
189 addr == &generic_bs_poke_1f ||
190 addr == &generic_bs_poke_2f ||
191 addr == &generic_bs_poke_4f ||
192 addr == &generic_bs_poke_8f);
196 svc_handler(struct thread *td, struct trapframe *frame)
199 if ((frame->tf_esr & ESR_ELx_ISS_MASK) == 0) {
203 call_trapsignal(td, SIGILL, ILL_ILLOPN, (void *)frame->tf_elr,
204 ESR_ELx_EXCEPTION(frame->tf_esr));
210 align_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
211 uint64_t far, int lower)
214 print_registers(frame);
215 print_gp_register("far", far);
216 printf(" esr: %.16lx\n", esr);
217 panic("Misaligned access from kernel space!");
220 call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_elr,
221 ESR_ELx_EXCEPTION(frame->tf_esr));
227 external_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
228 uint64_t far, int lower)
232 * Try to handle synchronous external aborts caused by
233 * bus_space_peek() and/or bus_space_poke() functions.
235 if (!lower && test_bs_fault((void *)frame->tf_elr)) {
236 frame->tf_elr = (uint64_t)generic_bs_fault;
240 print_registers(frame);
241 print_gp_register("far", far);
242 panic("Unhandled EL%d external data abort", lower ? 0: 1);
246 * It is unsafe to access the stack canary value stored in "td" until
247 * kernel map translation faults are handled, see the pmap_klookup() call below.
248 * Thus, stack-smashing detection with per-thread canaries must be disabled in
251 static void NO_PERTHREAD_SSP
252 data_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
253 uint64_t far, int lower)
258 int error, sig, ucode;
264 * According to the ARMv8-A rev. A.g, B2.10.5 "Load-Exclusive
265 * and Store-Exclusive instruction usage restrictions", state
266 * of the exclusive monitors after data abort exception is unknown.
278 map = &td->td_proc->p_vmspace->vm_map;
279 } else if (!ADDR_IS_CANONICAL(far)) {
280 /* We received a TBI/PAC/etc. fault from the kernel */
281 error = KERN_INVALID_ADDRESS;
283 } else if (ADDR_IS_KERNEL(far)) {
285 * Handle a special case: the data abort was caused by accessing
286 * a thread structure while its mapping was being promoted or
287 * demoted, as a consequence of the break-before-make rule. It
288 * is not safe to enable interrupts or dereference "td" before
289 * this case is handled.
291 * In principle, if pmap_klookup() fails, there is no need to
292 * call pmap_fault() below, but avoiding that call is not worth
295 if (ESR_ELx_EXCEPTION(esr) == EXCP_DATA_ABORT) {
296 switch (esr & ISS_DATA_DFSC_MASK) {
297 case ISS_DATA_DFSC_TF_L0:
298 case ISS_DATA_DFSC_TF_L1:
299 case ISS_DATA_DFSC_TF_L2:
300 case ISS_DATA_DFSC_TF_L3:
301 if (pmap_klookup(far, NULL))
310 map = &td->td_proc->p_vmspace->vm_map;
317 * Try to handle translation, access flag, and permission faults.
318 * Translation faults may occur as a result of the required
319 * break-before-make sequence used when promoting or demoting
320 * superpages. Such faults must not occur while holding the pmap lock,
321 * or pmap_fault() will recurse on that lock.
323 if ((lower || map == kernel_map || pcb->pcb_onfault != 0) &&
324 pmap_fault(map->pmap, esr, far) == KERN_SUCCESS)
327 KASSERT(td->td_md.md_spinlock_count == 0,
328 ("data abort with spinlock held"));
329 if (td->td_critnest != 0 || WITNESS_CHECK(WARN_SLEEPOK |
330 WARN_GIANTOK, NULL, "Kernel page fault") != 0) {
331 print_registers(frame);
332 print_gp_register("far", far);
333 printf(" esr: %.16lx\n", esr);
334 panic("data abort in critical section or under mutex");
337 switch (ESR_ELx_EXCEPTION(esr)) {
338 case EXCP_INSN_ABORT:
339 case EXCP_INSN_ABORT_L:
340 ftype = VM_PROT_EXECUTE;
344 * If the exception was because of a read or cache operation
345 * pass a read fault type into the vm code. Cache operations
346 * need read permission but will set the WnR flag when the
347 * memory is unmapped.
349 if ((esr & ISS_DATA_WnR) == 0 || (esr & ISS_DATA_CM) != 0)
350 ftype = VM_PROT_READ;
352 ftype = VM_PROT_WRITE;
356 /* Fault in the page. */
357 error = vm_fault_trap(map, far, ftype, VM_FAULT_NORMAL, &sig, &ucode);
358 if (error != KERN_SUCCESS) {
360 call_trapsignal(td, sig, ucode, (void *)far,
361 ESR_ELx_EXCEPTION(esr));
364 if (td->td_intr_nesting_level == 0 &&
365 pcb->pcb_onfault != 0) {
366 frame->tf_x[0] = error;
367 frame->tf_elr = pcb->pcb_onfault;
371 printf("Fatal data abort:\n");
372 print_registers(frame);
373 print_gp_register("far", far);
374 printf(" esr: %.16lx\n", esr);
377 if (debugger_on_trap) {
378 kdb_why = KDB_WHY_TRAP;
379 handled = kdb_trap(ESR_ELx_EXCEPTION(esr), 0,
381 kdb_why = KDB_WHY_UNSET;
386 panic("vm_fault failed: %lx error %d",
387 frame->tf_elr, error);
396 print_gp_register(const char *name, uint64_t value)
400 const char *sym_name;
405 printf(" %s: %16lx", name, value);
407 /* If this looks like a kernel address try to find the symbol */
408 if (value >= VM_MIN_KERNEL_ADDRESS) {
409 sym = db_search_symbol(value, DB_STGY_ANY, &offset);
410 if (sym != C_DB_SYM_NULL) {
411 db_symbol_values(sym, &sym_name, &sym_value);
412 printf(" (%s + %lx)", sym_name, offset);
420 print_registers(struct trapframe *frame)
425 for (reg = 0; reg < nitems(frame->tf_x); reg++) {
426 snprintf(name, sizeof(name), "%sx%d", (reg < 10) ? " " : "",
428 print_gp_register(name, frame->tf_x[reg]);
430 printf(" sp: %16lx\n", frame->tf_sp);
431 print_gp_register(" lr", frame->tf_lr);
432 print_gp_register("elr", frame->tf_elr);
433 printf("spsr: %16lx\n", frame->tf_spsr);
438 fpe_trap(struct thread *td, void *addr, uint32_t exception)
443 if ((exception & ISS_FP_TFV) != 0) {
444 if ((exception & ISS_FP_IOF) != 0)
446 else if ((exception & ISS_FP_DZF) != 0)
448 else if ((exception & ISS_FP_OFF) != 0)
450 else if ((exception & ISS_FP_UFF) != 0)
452 else if ((exception & ISS_FP_IXF) != 0)
455 call_trapsignal(td, SIGFPE, code, addr, exception);
460 * See the comment above data_abort().
462 void NO_PERTHREAD_SSP
463 do_el1h_sync(struct thread *td, struct trapframe *frame)
469 kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0);
471 /* Read the esr register to get the exception details */
473 exception = ESR_ELx_EXCEPTION(esr);
476 if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, exception))
481 "do_el1_sync: curthread: %p, esr %lx, elr: %lx, frame: %p", td,
482 esr, frame->tf_elr, frame);
485 * Enable debug exceptions if we aren't already handling one. They will
486 * be masked again in the exception handler's epilogue.
488 if (exception != EXCP_BRK && exception != EXCP_WATCHPT_EL1 &&
489 exception != EXCP_SOFTSTP_EL1)
496 if ((td->td_pcb->pcb_fpflags & PCB_FP_KERN) != 0) {
501 print_registers(frame);
502 printf(" esr: %.16lx\n", esr);
503 panic("VFP exception in the kernel");
506 case EXCP_INSN_ABORT:
507 case EXCP_DATA_ABORT:
508 dfsc = esr & ISS_DATA_DFSC_MASK;
509 if (dfsc < nitems(abort_handlers) &&
510 abort_handlers[dfsc] != NULL) {
511 abort_handlers[dfsc](td, frame, esr, far, 0);
513 print_registers(frame);
514 print_gp_register("far", far);
515 printf(" esr: %.16lx\n", esr);
516 panic("Unhandled EL1 %s abort: %x",
517 exception == EXCP_INSN_ABORT ? "instruction" :
523 if ((esr & ESR_ELx_ISS_MASK) == 0x40d && \
524 dtrace_invop_jump_addr != 0) {
525 dtrace_invop_jump_addr(frame);
530 kdb_trap(exception, 0, frame);
532 panic("No debugger in kernel.");
535 case EXCP_WATCHPT_EL1:
536 case EXCP_SOFTSTP_EL1:
538 kdb_trap(exception, 0, frame);
540 panic("No debugger in kernel.");
544 /* We can see this if the authentication on PAC fails */
545 print_registers(frame);
546 print_gp_register("far", far);
547 panic("FPAC kernel exception");
550 if (undef_insn(1, frame))
552 print_registers(frame);
553 print_gp_register("far", far);
554 panic("Undefined instruction: %08x",
555 *(uint32_t *)frame->tf_elr);
558 print_registers(frame);
559 print_gp_register("far", far);
560 panic("Unknown kernel exception %x esr_el1 %lx", exception,
566 do_el0_sync(struct thread *td, struct trapframe *frame)
568 pcpu_bp_harden bp_harden;
573 /* Check we have a sane environment when entering from userland */
574 KASSERT((uintptr_t)get_pcpu() >= VM_MIN_KERNEL_ADDRESS,
575 ("Invalid pcpu address from userland: %p (tpidr %lx)",
576 get_pcpu(), READ_SPECIALREG(tpidr_el1)));
578 kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0);
581 exception = ESR_ELx_EXCEPTION(esr);
582 if (exception == EXCP_INSN_ABORT_L && far > VM_MAXUSER_ADDRESS) {
584 * Userspace may be trying to train the branch predictor to
585 * attack the kernel. If we are on a CPU affected by this
586 * call the handler to clear the branch predictor state.
588 bp_harden = PCPU_GET(bp_harden);
589 if (bp_harden != NULL)
595 "do_el0_sync: curthread: %p, esr %lx, elr: %lx, frame: %p", td, esr,
596 frame->tf_elr, frame);
603 panic("VFP exception in userland");
608 fpe_trap(td, (void *)frame->tf_elr, esr);
611 panic("VFP exception in userland");
615 call_trapsignal(td, SIGILL, ILL_ILLTRP, (void *)frame->tf_elr,
621 svc_handler(td, frame);
623 case EXCP_INSN_ABORT_L:
624 case EXCP_DATA_ABORT_L:
625 case EXCP_DATA_ABORT:
626 dfsc = esr & ISS_DATA_DFSC_MASK;
627 if (dfsc < nitems(abort_handlers) &&
628 abort_handlers[dfsc] != NULL)
629 abort_handlers[dfsc](td, frame, esr, far, 1);
631 print_registers(frame);
632 print_gp_register("far", far);
633 printf(" esr: %.16lx\n", esr);
634 panic("Unhandled EL0 %s abort: %x",
635 exception == EXCP_INSN_ABORT_L ? "instruction" :
640 if (!undef_insn(0, frame))
641 call_trapsignal(td, SIGILL, ILL_ILLTRP, (void *)far,
646 call_trapsignal(td, SIGILL, ILL_ILLOPN, (void *)frame->tf_elr,
651 call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_sp,
656 call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_elr,
662 #ifdef COMPAT_FREEBSD32
664 #endif /* COMPAT_FREEBSD32 */
665 call_trapsignal(td, SIGTRAP, TRAP_BRKPT, (void *)frame->tf_elr,
669 case EXCP_WATCHPT_EL0:
670 call_trapsignal(td, SIGTRAP, TRAP_TRACE, (void *)far,
676 * The CPU can raise EXCP_MSR when userspace executes an mrs
677 * instruction to access a special register userspace doesn't
680 if (!undef_insn(0, frame))
681 call_trapsignal(td, SIGILL, ILL_PRVOPC,
682 (void *)frame->tf_elr, exception);
685 case EXCP_SOFTSTP_EL0:
686 PROC_LOCK(td->td_proc);
687 if ((td->td_dbgflags & TDB_STEP) != 0) {
688 td->td_frame->tf_spsr &= ~PSR_SS;
689 td->td_pcb->pcb_flags &= ~PCB_SINGLE_STEP;
690 WRITE_SPECIALREG(mdscr_el1,
691 READ_SPECIALREG(mdscr_el1) & ~MDSCR_SS);
693 PROC_UNLOCK(td->td_proc);
694 call_trapsignal(td, SIGTRAP, TRAP_TRACE,
695 (void *)frame->tf_elr, exception);
699 call_trapsignal(td, SIGBUS, BUS_OBJERR, (void *)frame->tf_elr,
705 KASSERT((td->td_pcb->pcb_fpflags & ~PCB_FP_USERMASK) == 0,
706 ("Kernel VFP flags set while entering userspace"));
708 td->td_pcb->pcb_fpusaved == &td->td_pcb->pcb_fpustate,
709 ("Kernel VFP state in use when entering userspace"));
713 * TODO: We will need to handle these later when we support ARMv8.2 RAS.
716 do_serror(struct trapframe *frame)
720 kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0);
724 print_registers(frame);
725 print_gp_register("far", far);
726 printf(" esr: %.16lx\n", esr);
727 panic("Unhandled System Error");
731 unhandled_exception(struct trapframe *frame)
735 kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0);
739 print_registers(frame);
740 print_gp_register("far", far);
741 printf(" esr: %.16lx\n", esr);
742 panic("Unhandled exception");