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>
35 #include <sys/kernel.h>
38 #include <sys/mutex.h>
40 #include <sys/ptrace.h>
41 #include <sys/syscall.h>
42 #include <sys/sysent.h>
49 #include <vm/vm_kern.h>
50 #include <vm/vm_map.h>
51 #include <vm/vm_param.h>
52 #include <vm/vm_extern.h>
54 #include <machine/frame.h>
55 #include <machine/md_var.h>
56 #include <machine/pcb.h>
57 #include <machine/pcpu.h>
58 #include <machine/undefined.h>
61 #include <sys/dtrace_bsd.h>
65 #include <machine/vfp.h>
69 #include <machine/db_machdep.h>
74 #include <ddb/db_sym.h>
77 /* Called from exception.S */
78 void do_el1h_sync(struct thread *, struct trapframe *);
79 void do_el0_sync(struct thread *, struct trapframe *, uint64_t far);
80 void do_el0_error(struct trapframe *);
81 void do_serror(struct trapframe *);
82 void unhandled_exception(struct trapframe *);
84 static void print_gp_register(const char *name, uint64_t value);
85 static void print_registers(struct trapframe *frame);
87 int (*dtrace_invop_jump_addr)(struct trapframe *);
89 typedef void (abort_handler)(struct thread *, struct trapframe *, uint64_t,
92 static abort_handler align_abort;
93 static abort_handler data_abort;
94 static abort_handler external_abort;
96 static abort_handler *abort_handlers[] = {
97 [ISS_DATA_DFSC_TF_L0] = data_abort,
98 [ISS_DATA_DFSC_TF_L1] = data_abort,
99 [ISS_DATA_DFSC_TF_L2] = data_abort,
100 [ISS_DATA_DFSC_TF_L3] = data_abort,
101 [ISS_DATA_DFSC_AFF_L1] = data_abort,
102 [ISS_DATA_DFSC_AFF_L2] = data_abort,
103 [ISS_DATA_DFSC_AFF_L3] = data_abort,
104 [ISS_DATA_DFSC_PF_L1] = data_abort,
105 [ISS_DATA_DFSC_PF_L2] = data_abort,
106 [ISS_DATA_DFSC_PF_L3] = data_abort,
107 [ISS_DATA_DFSC_ALIGN] = align_abort,
108 [ISS_DATA_DFSC_EXT] = external_abort,
109 [ISS_DATA_DFSC_EXT_L0] = external_abort,
110 [ISS_DATA_DFSC_EXT_L1] = external_abort,
111 [ISS_DATA_DFSC_EXT_L2] = external_abort,
112 [ISS_DATA_DFSC_EXT_L3] = external_abort,
113 [ISS_DATA_DFSC_ECC] = external_abort,
114 [ISS_DATA_DFSC_ECC_L0] = external_abort,
115 [ISS_DATA_DFSC_ECC_L1] = external_abort,
116 [ISS_DATA_DFSC_ECC_L2] = external_abort,
117 [ISS_DATA_DFSC_ECC_L3] = external_abort,
121 call_trapsignal(struct thread *td, int sig, int code, void *addr, int trapno)
125 ksiginfo_init_trap(&ksi);
129 ksi.ksi_trapno = trapno;
130 trapsignal(td, &ksi);
134 cpu_fetch_syscall_args(struct thread *td)
137 syscallarg_t *ap, *dst_ap;
138 struct syscall_args *sa;
142 ap = td->td_frame->tf_x;
143 dst_ap = &sa->args[0];
145 sa->code = td->td_frame->tf_x[8];
146 sa->original_code = sa->code;
148 if (__predict_false(sa->code == SYS_syscall || sa->code == SYS___syscall)) {
154 if (__predict_false(sa->code >= p->p_sysent->sv_size))
155 sa->callp = &p->p_sysent->sv_table[0];
157 sa->callp = &p->p_sysent->sv_table[sa->code];
159 KASSERT(sa->callp->sy_narg <= nitems(sa->args),
160 ("Syscall %d takes too many arguments", sa->code));
162 memcpy(dst_ap, ap, (nitems(sa->args) - 1) * sizeof(*dst_ap));
164 td->td_retval[0] = 0;
165 td->td_retval[1] = 0;
170 #include "../../kern/subr_syscall.c"
173 * Test for fault generated by given access instruction in
174 * bus_peek_<foo> or bus_poke_<foo> bus function.
176 extern uint32_t generic_bs_peek_1f, generic_bs_peek_2f;
177 extern uint32_t generic_bs_peek_4f, generic_bs_peek_8f;
178 extern uint32_t generic_bs_poke_1f, generic_bs_poke_2f;
179 extern uint32_t generic_bs_poke_4f, generic_bs_poke_8f;
182 test_bs_fault(void *addr)
184 return (addr == &generic_bs_peek_1f ||
185 addr == &generic_bs_peek_2f ||
186 addr == &generic_bs_peek_4f ||
187 addr == &generic_bs_peek_8f ||
188 addr == &generic_bs_poke_1f ||
189 addr == &generic_bs_poke_2f ||
190 addr == &generic_bs_poke_4f ||
191 addr == &generic_bs_poke_8f);
195 svc_handler(struct thread *td, struct trapframe *frame)
198 if ((frame->tf_esr & ESR_ELx_ISS_MASK) == 0) {
202 call_trapsignal(td, SIGILL, ILL_ILLOPN, (void *)frame->tf_elr,
203 ESR_ELx_EXCEPTION(frame->tf_esr));
209 align_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
210 uint64_t far, int lower)
213 print_registers(frame);
214 print_gp_register("far", far);
215 printf(" esr: %.8lx\n", esr);
216 panic("Misaligned access from kernel space!");
219 call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_elr,
220 ESR_ELx_EXCEPTION(frame->tf_esr));
226 external_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
227 uint64_t far, int lower)
231 * Try to handle synchronous external aborts caused by
232 * bus_space_peek() and/or bus_space_poke() functions.
234 if (!lower && test_bs_fault((void *)frame->tf_elr)) {
235 frame->tf_elr = (uint64_t)generic_bs_fault;
239 print_registers(frame);
240 print_gp_register("far", far);
241 panic("Unhandled EL%d external data abort", lower ? 0: 1);
245 * It is unsafe to access the stack canary value stored in "td" until
246 * kernel map translation faults are handled, see the pmap_klookup() call below.
247 * Thus, stack-smashing detection with per-thread canaries must be disabled in
250 static void NO_PERTHREAD_SSP
251 data_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
252 uint64_t far, int lower)
257 int error, sig, ucode;
263 * According to the ARMv8-A rev. A.g, B2.10.5 "Load-Exclusive
264 * and Store-Exclusive instruction usage restrictions", state
265 * of the exclusive monitors after data abort exception is unknown.
277 map = &td->td_proc->p_vmspace->vm_map;
278 } else if (!ADDR_IS_CANONICAL(far)) {
279 /* We received a TBI/PAC/etc. fault from the kernel */
280 error = KERN_INVALID_ADDRESS;
282 } else if (ADDR_IS_KERNEL(far)) {
284 * Handle a special case: the data abort was caused by accessing
285 * a thread structure while its mapping was being promoted or
286 * demoted, as a consequence of the break-before-make rule. It
287 * is not safe to enable interrupts or dereference "td" before
288 * this case is handled.
290 * In principle, if pmap_klookup() fails, there is no need to
291 * call pmap_fault() below, but avoiding that call is not worth
294 if (ESR_ELx_EXCEPTION(esr) == EXCP_DATA_ABORT) {
295 switch (esr & ISS_DATA_DFSC_MASK) {
296 case ISS_DATA_DFSC_TF_L0:
297 case ISS_DATA_DFSC_TF_L1:
298 case ISS_DATA_DFSC_TF_L2:
299 case ISS_DATA_DFSC_TF_L3:
300 if (pmap_klookup(far, NULL))
309 map = &td->td_proc->p_vmspace->vm_map;
316 * Try to handle translation, access flag, and permission faults.
317 * Translation faults may occur as a result of the required
318 * break-before-make sequence used when promoting or demoting
319 * superpages. Such faults must not occur while holding the pmap lock,
320 * or pmap_fault() will recurse on that lock.
322 if ((lower || map == kernel_map || pcb->pcb_onfault != 0) &&
323 pmap_fault(map->pmap, esr, far) == KERN_SUCCESS)
326 KASSERT(td->td_md.md_spinlock_count == 0,
327 ("data abort with spinlock held"));
328 if (td->td_critnest != 0 || WITNESS_CHECK(WARN_SLEEPOK |
329 WARN_GIANTOK, NULL, "Kernel page fault") != 0) {
330 print_registers(frame);
331 print_gp_register("far", far);
332 printf(" esr: %.8lx\n", esr);
333 panic("data abort in critical section or under mutex");
336 switch (ESR_ELx_EXCEPTION(esr)) {
337 case EXCP_INSN_ABORT:
338 case EXCP_INSN_ABORT_L:
339 ftype = VM_PROT_EXECUTE;
343 * If the exception was because of a read or cache operation
344 * pass a read fault type into the vm code. Cache operations
345 * need read permission but will set the WnR flag when the
346 * memory is unmapped.
348 if ((esr & ISS_DATA_WnR) == 0 || (esr & ISS_DATA_CM) != 0)
349 ftype = VM_PROT_READ;
351 ftype = VM_PROT_WRITE;
355 /* Fault in the page. */
356 error = vm_fault_trap(map, far, ftype, VM_FAULT_NORMAL, &sig, &ucode);
357 if (error != KERN_SUCCESS) {
359 call_trapsignal(td, sig, ucode, (void *)far,
360 ESR_ELx_EXCEPTION(esr));
363 if (td->td_intr_nesting_level == 0 &&
364 pcb->pcb_onfault != 0) {
365 frame->tf_x[0] = error;
366 frame->tf_elr = pcb->pcb_onfault;
370 printf("Fatal data abort:\n");
371 print_registers(frame);
372 print_gp_register("far", far);
373 printf(" esr: %.8lx\n", esr);
376 if (debugger_on_trap) {
377 kdb_why = KDB_WHY_TRAP;
378 handled = kdb_trap(ESR_ELx_EXCEPTION(esr), 0,
380 kdb_why = KDB_WHY_UNSET;
385 panic("vm_fault failed: %lx error %d",
386 frame->tf_elr, error);
395 print_gp_register(const char *name, uint64_t value)
399 const char *sym_name;
404 printf(" %s: %16lx", name, value);
406 /* If this looks like a kernel address try to find the symbol */
407 if (value >= VM_MIN_KERNEL_ADDRESS) {
408 sym = db_search_symbol(value, DB_STGY_ANY, &offset);
409 if (sym != C_DB_SYM_NULL) {
410 db_symbol_values(sym, &sym_name, &sym_value);
411 printf(" (%s + %lx)", sym_name, offset);
419 print_registers(struct trapframe *frame)
424 for (reg = 0; reg < nitems(frame->tf_x); reg++) {
425 snprintf(name, sizeof(name), "%sx%d", (reg < 10) ? " " : "",
427 print_gp_register(name, frame->tf_x[reg]);
429 printf(" sp: %16lx\n", frame->tf_sp);
430 print_gp_register(" lr", frame->tf_lr);
431 print_gp_register("elr", frame->tf_elr);
432 printf("spsr: %8x\n", frame->tf_spsr);
437 fpe_trap(struct thread *td, void *addr, uint32_t exception)
442 if ((exception & ISS_FP_TFV) != 0) {
443 if ((exception & ISS_FP_IOF) != 0)
445 else if ((exception & ISS_FP_DZF) != 0)
447 else if ((exception & ISS_FP_OFF) != 0)
449 else if ((exception & ISS_FP_UFF) != 0)
451 else if ((exception & ISS_FP_IXF) != 0)
454 call_trapsignal(td, SIGFPE, code, addr, exception);
459 * See the comment above data_abort().
461 void NO_PERTHREAD_SSP
462 do_el1h_sync(struct thread *td, struct trapframe *frame)
468 /* Read the esr register to get the exception details */
470 exception = ESR_ELx_EXCEPTION(esr);
473 if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, exception))
478 "do_el1_sync: curthread: %p, esr %lx, elr: %lx, frame: %p", td,
479 esr, frame->tf_elr, frame);
482 * Enable debug exceptions if we aren't already handling one. They will
483 * be masked again in the exception handler's epilogue.
485 if (exception != EXCP_BRK && exception != EXCP_WATCHPT_EL1 &&
486 exception != EXCP_SOFTSTP_EL1)
493 if ((td->td_pcb->pcb_fpflags & PCB_FP_KERN) != 0) {
498 print_registers(frame);
499 printf(" esr: %.8lx\n", esr);
500 panic("VFP exception in the kernel");
503 case EXCP_INSN_ABORT:
504 case EXCP_DATA_ABORT:
505 far = READ_SPECIALREG(far_el1);
506 dfsc = esr & ISS_DATA_DFSC_MASK;
507 if (dfsc < nitems(abort_handlers) &&
508 abort_handlers[dfsc] != NULL) {
509 abort_handlers[dfsc](td, frame, esr, far, 0);
511 print_registers(frame);
512 print_gp_register("far", far);
513 printf(" esr: %.8lx\n", esr);
514 panic("Unhandled EL1 %s abort: %x",
515 exception == EXCP_INSN_ABORT ? "instruction" :
521 if ((esr & ESR_ELx_ISS_MASK) == 0x40d && \
522 dtrace_invop_jump_addr != 0) {
523 dtrace_invop_jump_addr(frame);
528 kdb_trap(exception, 0, frame);
530 panic("No debugger in kernel.");
533 case EXCP_WATCHPT_EL1:
534 case EXCP_SOFTSTP_EL1:
536 kdb_trap(exception, 0, frame);
538 panic("No debugger in kernel.");
542 /* We can see this if the authentication on PAC fails */
543 print_registers(frame);
544 printf(" far: %16lx\n", READ_SPECIALREG(far_el1));
545 panic("FPAC kernel exception");
548 if (undef_insn(1, frame))
550 printf("Undefined instruction: %08x\n",
551 *(uint32_t *)frame->tf_elr);
554 print_registers(frame);
555 print_gp_register("far", READ_SPECIALREG(far_el1));
556 panic("Unknown kernel exception %x esr_el1 %lx", exception,
562 do_el0_sync(struct thread *td, struct trapframe *frame, uint64_t far)
564 pcpu_bp_harden bp_harden;
569 /* Check we have a sane environment when entering from userland */
570 KASSERT((uintptr_t)get_pcpu() >= VM_MIN_KERNEL_ADDRESS,
571 ("Invalid pcpu address from userland: %p (tpidr %lx)",
572 get_pcpu(), READ_SPECIALREG(tpidr_el1)));
575 exception = ESR_ELx_EXCEPTION(esr);
576 if (exception == EXCP_INSN_ABORT_L && far > VM_MAXUSER_ADDRESS) {
578 * Userspace may be trying to train the branch predictor to
579 * attack the kernel. If we are on a CPU affected by this
580 * call the handler to clear the branch predictor state.
582 bp_harden = PCPU_GET(bp_harden);
583 if (bp_harden != NULL)
589 "do_el0_sync: curthread: %p, esr %lx, elr: %lx, frame: %p", td, esr,
590 frame->tf_elr, frame);
597 panic("VFP exception in userland");
602 fpe_trap(td, (void *)frame->tf_elr, esr);
605 panic("VFP exception in userland");
609 call_trapsignal(td, SIGILL, ILL_ILLTRP, (void *)frame->tf_elr,
615 svc_handler(td, frame);
617 case EXCP_INSN_ABORT_L:
618 case EXCP_DATA_ABORT_L:
619 case EXCP_DATA_ABORT:
620 dfsc = esr & ISS_DATA_DFSC_MASK;
621 if (dfsc < nitems(abort_handlers) &&
622 abort_handlers[dfsc] != NULL)
623 abort_handlers[dfsc](td, frame, esr, far, 1);
625 print_registers(frame);
626 print_gp_register("far", far);
627 printf(" esr: %.8lx\n", esr);
628 panic("Unhandled EL0 %s abort: %x",
629 exception == EXCP_INSN_ABORT_L ? "instruction" :
634 if (!undef_insn(0, frame))
635 call_trapsignal(td, SIGILL, ILL_ILLTRP, (void *)far,
640 call_trapsignal(td, SIGILL, ILL_ILLOPN, (void *)frame->tf_elr,
645 call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_sp,
650 call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_elr,
656 #ifdef COMPAT_FREEBSD32
658 #endif /* COMPAT_FREEBSD32 */
659 call_trapsignal(td, SIGTRAP, TRAP_BRKPT, (void *)frame->tf_elr,
663 case EXCP_WATCHPT_EL0:
664 call_trapsignal(td, SIGTRAP, TRAP_TRACE, (void *)far,
670 * The CPU can raise EXCP_MSR when userspace executes an mrs
671 * instruction to access a special register userspace doesn't
674 if (!undef_insn(0, frame))
675 call_trapsignal(td, SIGILL, ILL_PRVOPC,
676 (void *)frame->tf_elr, exception);
679 case EXCP_SOFTSTP_EL0:
680 PROC_LOCK(td->td_proc);
681 if ((td->td_dbgflags & TDB_STEP) != 0) {
682 td->td_frame->tf_spsr &= ~PSR_SS;
683 td->td_pcb->pcb_flags &= ~PCB_SINGLE_STEP;
684 WRITE_SPECIALREG(mdscr_el1,
685 READ_SPECIALREG(mdscr_el1) & ~MDSCR_SS);
687 PROC_UNLOCK(td->td_proc);
688 call_trapsignal(td, SIGTRAP, TRAP_TRACE,
689 (void *)frame->tf_elr, exception);
693 call_trapsignal(td, SIGBUS, BUS_OBJERR, (void *)frame->tf_elr,
699 KASSERT((td->td_pcb->pcb_fpflags & ~PCB_FP_USERMASK) == 0,
700 ("Kernel VFP flags set while entering userspace"));
702 td->td_pcb->pcb_fpusaved == &td->td_pcb->pcb_fpustate,
703 ("Kernel VFP state in use when entering userspace"));
707 * TODO: We will need to handle these later when we support ARMv8.2 RAS.
710 do_serror(struct trapframe *frame)
714 far = READ_SPECIALREG(far_el1);
717 print_registers(frame);
718 print_gp_register("far", far);
719 printf(" esr: %.8lx\n", esr);
720 panic("Unhandled System Error");
724 unhandled_exception(struct trapframe *frame)
728 far = READ_SPECIALREG(far_el1);
731 print_registers(frame);
732 print_gp_register("far", far);
733 printf(" esr: %.8lx\n", esr);
734 panic("Unhandled exception");