/*-
 * Copyright (c) 2014 Andrew Turner
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#include "opt_ddb.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/asan.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/msan.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/ptrace.h>
#include <sys/syscall.h>
#include <sys/sysent.h>
#ifdef KDB
#include <sys/kdb.h>
#endif

#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_kern.h>
#include <vm/vm_map.h>
#include <vm/vm_param.h>
#include <vm/vm_extern.h>

#include <machine/frame.h>
#include <machine/md_var.h>
#include <machine/pcb.h>
#include <machine/pcpu.h>
#include <machine/undefined.h>

#ifdef KDTRACE_HOOKS
#include <sys/dtrace_bsd.h>
#endif

#ifdef VFP
#include <machine/vfp.h>
#endif

#ifdef KDB
#include <machine/db_machdep.h>
#endif

#ifdef DDB
#include <ddb/ddb.h>
#include <ddb/db_sym.h>
#endif

/* Called from exception.S */
void do_el1h_sync(struct thread *, struct trapframe *);
void do_el0_sync(struct thread *, struct trapframe *);
void do_el0_error(struct trapframe *);
void do_serror(struct trapframe *);
void unhandled_exception(struct trapframe *);

static void print_gp_register(const char *name, uint64_t value);
static void print_registers(struct trapframe *frame);

int (*dtrace_invop_jump_addr)(struct trapframe *);

u_long cnt_efirt_faults;
int print_efirt_faults;

typedef void (abort_handler)(struct thread *, struct trapframe *, uint64_t,
    uint64_t, int);

static abort_handler align_abort;
static abort_handler data_abort;
static abort_handler external_abort;

static abort_handler *abort_handlers[] = {
        [ISS_DATA_DFSC_TF_L0] = data_abort,
        [ISS_DATA_DFSC_TF_L1] = data_abort,
        [ISS_DATA_DFSC_TF_L2] = data_abort,
        [ISS_DATA_DFSC_TF_L3] = data_abort,
        [ISS_DATA_DFSC_AFF_L1] = data_abort,
        [ISS_DATA_DFSC_AFF_L2] = data_abort,
        [ISS_DATA_DFSC_AFF_L3] = data_abort,
        [ISS_DATA_DFSC_PF_L1] = data_abort,
        [ISS_DATA_DFSC_PF_L2] = data_abort,
        [ISS_DATA_DFSC_PF_L3] = data_abort,
        [ISS_DATA_DFSC_ALIGN] = align_abort,
        [ISS_DATA_DFSC_EXT] =  external_abort,
        [ISS_DATA_DFSC_EXT_L0] =  external_abort,
        [ISS_DATA_DFSC_EXT_L1] =  external_abort,
        [ISS_DATA_DFSC_EXT_L2] =  external_abort,
        [ISS_DATA_DFSC_EXT_L3] =  external_abort,
        [ISS_DATA_DFSC_ECC] =  external_abort,
        [ISS_DATA_DFSC_ECC_L0] =  external_abort,
        [ISS_DATA_DFSC_ECC_L1] =  external_abort,
        [ISS_DATA_DFSC_ECC_L2] =  external_abort,
        [ISS_DATA_DFSC_ECC_L3] =  external_abort,
};

static __inline void
call_trapsignal(struct thread *td, int sig, int code, void *addr, int trapno)
{
        ksiginfo_t ksi;

        ksiginfo_init_trap(&ksi);
        ksi.ksi_signo = sig;
        ksi.ksi_code = code;
        ksi.ksi_addr = addr;
        ksi.ksi_trapno = trapno;
        trapsignal(td, &ksi);
}

int
cpu_fetch_syscall_args(struct thread *td)
{
        struct proc *p;
        syscallarg_t *ap, *dst_ap;
        struct syscall_args *sa;

        p = td->td_proc;
        sa = &td->td_sa;
        ap = td->td_frame->tf_x;
        dst_ap = &sa->args[0];

        sa->code = td->td_frame->tf_x[8];
        sa->original_code = sa->code;

        if (__predict_false(sa->code == SYS_syscall || sa->code == SYS___syscall)) {
                sa->code = *ap++;
        } else {
                *dst_ap++ = *ap++;
        }

        if (__predict_false(sa->code >= p->p_sysent->sv_size))
                sa->callp = &nosys_sysent;
        else
                sa->callp = &p->p_sysent->sv_table[sa->code];

        KASSERT(sa->callp->sy_narg <= nitems(sa->args),
            ("Syscall %d takes too many arguments", sa->code));

        memcpy(dst_ap, ap, (nitems(sa->args) - 1) * sizeof(*dst_ap));

        td->td_retval[0] = 0;
        td->td_retval[1] = 0;

        return (0);
}

#include "../../kern/subr_syscall.c"

/*
 * Test for fault generated by given access instruction in
 * bus_peek_<foo> or bus_poke_<foo> bus function.
 */
extern uint32_t generic_bs_peek_1f, generic_bs_peek_2f;
extern uint32_t generic_bs_peek_4f, generic_bs_peek_8f;
extern uint32_t generic_bs_poke_1f, generic_bs_poke_2f;
extern uint32_t generic_bs_poke_4f, generic_bs_poke_8f;

static bool
test_bs_fault(void *addr)
{
        return (addr == &generic_bs_peek_1f ||
            addr == &generic_bs_peek_2f ||
            addr == &generic_bs_peek_4f ||
            addr == &generic_bs_peek_8f ||
            addr == &generic_bs_poke_1f ||
            addr == &generic_bs_poke_2f ||
            addr == &generic_bs_poke_4f ||
            addr == &generic_bs_poke_8f);
}

static bool
svc_handler(struct thread *td, struct trapframe *frame)
{

        if ((frame->tf_esr & ESR_ELx_ISS_MASK) == 0) {
                syscallenter(td);
                syscallret(td);
                /* Skip userret as syscallret already called it */
                return (true);
        } else {
                call_trapsignal(td, SIGILL, ILL_ILLOPN, (void *)frame->tf_elr,
                    ESR_ELx_EXCEPTION(frame->tf_esr));
                return (false);
        }
}

static void
align_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
    uint64_t far, int lower)
{
        if (!lower) {
                print_registers(frame);
                print_gp_register("far", far);
                printf(" esr: 0x%.16lx\n", esr);
                panic("Misaligned access from kernel space!");
        }

        call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_elr,
            ESR_ELx_EXCEPTION(frame->tf_esr));
}


static void
external_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
    uint64_t far, int lower)
{
        if (lower) {
                call_trapsignal(td, SIGBUS, BUS_OBJERR, (void *)far,
                    ESR_ELx_EXCEPTION(frame->tf_esr));
                return;
        }

        /*
         * Try to handle synchronous external aborts caused by
         * bus_space_peek() and/or bus_space_poke() functions.
         */
        if (test_bs_fault((void *)frame->tf_elr)) {
                frame->tf_elr = (uint64_t)generic_bs_fault;
                return;
        }

        print_registers(frame);
        print_gp_register("far", far);
        printf(" esr: 0x%.16lx\n", esr);
        panic("Unhandled external data abort");
}

/*
 * It is unsafe to access the stack canary value stored in "td" until
 * kernel map translation faults are handled, see the pmap_klookup() call below.
 * Thus, stack-smashing detection with per-thread canaries must be disabled in
 * this function.
 */
static void NO_PERTHREAD_SSP
data_abort(struct thread *td, struct trapframe *frame, uint64_t esr,
    uint64_t far, int lower)
{
        struct vm_map *map;
        struct pcb *pcb;
        vm_offset_t fault_va;
        vm_prot_t ftype;
        int error, sig, ucode;
#ifdef KDB
        bool handled;
#endif

        /*
         * According to the ARMv8-A rev. A.g, B2.10.5 "Load-Exclusive
         * and Store-Exclusive instruction usage restrictions", state
         * of the exclusive monitors after data abort exception is unknown.
         */
        clrex();

#ifdef KDB
        if (kdb_active) {
                kdb_reenter();
                return;
        }
#endif

        fault_va = far;
        if (lower) {
                map = &td->td_proc->p_vmspace->vm_map;
                if ((td->td_proc->p_md.md_tcr & TCR_TBI0) != 0)
                        fault_va = ADDR_MAKE_CANONICAL(far);
        } else if (!ADDR_IS_CANONICAL(far)) {
                /* We received a TBI/PAC/etc. fault from the kernel */
                error = KERN_INVALID_ADDRESS;
                pcb = td->td_pcb;
                goto bad_far;
        } else if (ADDR_IS_KERNEL(far)) {
                /*
                 * Handle a special case: the data abort was caused by accessing
                 * a thread structure while its mapping was being promoted or
                 * demoted, as a consequence of the break-before-make rule.  It
                 * is not safe to enable interrupts or dereference "td" before
                 * this case is handled.
                 *
                 * In principle, if pmap_klookup() fails, there is no need to
                 * call pmap_fault() below, but avoiding that call is not worth
                 * the effort.
                 */
                if (ESR_ELx_EXCEPTION(esr) == EXCP_DATA_ABORT) {
                        switch (esr & ISS_DATA_DFSC_MASK) {
                        case ISS_DATA_DFSC_TF_L0:
                        case ISS_DATA_DFSC_TF_L1:
                        case ISS_DATA_DFSC_TF_L2:
                        case ISS_DATA_DFSC_TF_L3:
                                if (pmap_klookup(far, NULL))
                                        return;
                                break;
                        }
                }
                if (td->td_md.md_spinlock_count == 0 &&
                    (frame->tf_spsr & PSR_DAIF_INTR) != PSR_DAIF_INTR) {
                        MPASS((frame->tf_spsr & PSR_DAIF_INTR) == 0);
                        intr_enable();
                }
                map = kernel_map;
        } else {
                if (td->td_md.md_spinlock_count == 0 &&
                    (frame->tf_spsr & PSR_DAIF_INTR) != PSR_DAIF_INTR) {
                        MPASS((frame->tf_spsr & PSR_DAIF_INTR) == 0);
                        intr_enable();
                }
                map = &td->td_proc->p_vmspace->vm_map;
                if (map == NULL)
                        map = kernel_map;
        }
        pcb = td->td_pcb;

        /*
         * Try to handle translation, access flag, and permission faults.
         * Translation faults may occur as a result of the required
         * break-before-make sequence used when promoting or demoting
         * superpages.  Such faults must not occur while holding the pmap lock,
         * or pmap_fault() will recurse on that lock.
         */
        if ((lower || map == kernel_map || pcb->pcb_onfault != 0) &&
            pmap_fault(map->pmap, esr, fault_va) == KERN_SUCCESS)
                return;

#ifdef INVARIANTS
        if (td->td_md.md_spinlock_count != 0) {
                print_registers(frame);
                print_gp_register("far", far);
                printf(" esr: 0x%.16lx\n", esr);
                panic("data abort with spinlock held (spinlock count %d != 0)",
                    td->td_md.md_spinlock_count);
        }
#endif
        if ((td->td_pflags & TDP_NOFAULTING) == 0 &&
            (td->td_critnest != 0 || WITNESS_CHECK(WARN_SLEEPOK |
            WARN_GIANTOK, NULL, "Kernel page fault") != 0)) {
                print_registers(frame);
                print_gp_register("far", far);
                printf(" esr: 0x%.16lx\n", esr);
                panic("data abort in critical section or under mutex");
        }

        switch (ESR_ELx_EXCEPTION(esr)) {
        case EXCP_INSN_ABORT:
        case EXCP_INSN_ABORT_L:
                ftype = VM_PROT_EXECUTE;
                break;
        default:
                /*
                 * If the exception was because of a read or cache operation
                 * pass a read fault type into the vm code. Cache operations
                 * need read permission but will set the WnR flag when the
                 * memory is unmapped.
                 */
                if ((esr & ISS_DATA_WnR) == 0 || (esr & ISS_DATA_CM) != 0)
                        ftype = VM_PROT_READ;
                else
                        ftype = VM_PROT_WRITE;
                break;
        }

        /* Fault in the page. */
        error = vm_fault_trap(map, fault_va, ftype, VM_FAULT_NORMAL, &sig,
            &ucode);
        if (error != KERN_SUCCESS) {
                if (lower) {
                        call_trapsignal(td, sig, ucode, (void *)far,
                            ESR_ELx_EXCEPTION(esr));
                } else {
bad_far:
                        if (td->td_intr_nesting_level == 0 &&
                            pcb->pcb_onfault != 0) {
                                frame->tf_elr = pcb->pcb_onfault;
                                return;
                        }

                        printf("Fatal data abort:\n");
                        print_registers(frame);
                        print_gp_register("far", far);
                        printf(" esr: 0x%.16lx\n", esr);

#ifdef KDB
                        if (debugger_on_trap) {
                                kdb_why = KDB_WHY_TRAP;
                                handled = kdb_trap(ESR_ELx_EXCEPTION(esr), 0,
                                    frame);
                                kdb_why = KDB_WHY_UNSET;
                                if (handled)
                                        return;
                        }
#endif
                        panic("vm_fault failed: 0x%lx error %d",
                            frame->tf_elr, error);
                }
        }
}

static void
print_gp_register(const char *name, uint64_t value)
{
#if defined(DDB)
        c_db_sym_t sym;
        const char *sym_name;
        db_expr_t sym_value;
        db_expr_t offset;
#endif

        printf(" %s: 0x%.16lx", name, value);
#if defined(DDB)
        /* If this looks like a kernel address try to find the symbol */
        if (value >= VM_MIN_KERNEL_ADDRESS) {
                sym = db_search_symbol(value, DB_STGY_ANY, &offset);
                if (sym != C_DB_SYM_NULL) {
                        db_symbol_values(sym, &sym_name, &sym_value);
                        printf(" (%s + 0x%lx)", sym_name, offset);
                }
        }
#endif
        printf("\n");
}

static void
print_registers(struct trapframe *frame)
{
        char name[4];
        u_int reg;

        for (reg = 0; reg < nitems(frame->tf_x); reg++) {
                snprintf(name, sizeof(name), "%sx%d", (reg < 10) ? " " : "",
                    reg);
                print_gp_register(name, frame->tf_x[reg]);
        }
        printf("  sp: 0x%.16lx\n", frame->tf_sp);
        print_gp_register(" lr", frame->tf_lr);
        print_gp_register("elr", frame->tf_elr);
        printf("spsr: 0x%.16lx\n", frame->tf_spsr);
}

#ifdef VFP
static void
fpe_trap(struct thread *td, void *addr, uint32_t exception)
{
        int code;

        code = FPE_FLTIDO;
        if ((exception & ISS_FP_TFV) != 0) {
                if ((exception & ISS_FP_IOF) != 0)
                        code = FPE_FLTINV;
                else if ((exception & ISS_FP_DZF) != 0)
                        code = FPE_FLTDIV;
                else if ((exception & ISS_FP_OFF) != 0)
                        code = FPE_FLTOVF;
                else if ((exception & ISS_FP_UFF) != 0)
                        code = FPE_FLTUND;
                else if ((exception & ISS_FP_IXF) != 0)
                        code = FPE_FLTRES;
        }
        call_trapsignal(td, SIGFPE, code, addr, exception);
}
#endif

static void
handle_moe(struct thread *td, struct trapframe *frame, uint64_t esr)
{
        uint64_t src;
        uint64_t dest;
        uint64_t size;
        int src_reg;
        int dest_reg;
        int size_reg;
        int format_option;

        format_option = esr & ISS_MOE_FORMAT_OPTION_MASK;
        dest_reg = (esr & ISS_MOE_DESTREG_MASK) >> ISS_MOE_DESTREG_SHIFT;
        size_reg = (esr & ISS_MOE_SIZEREG_MASK) >> ISS_MOE_SIZEREG_SHIFT;
        dest = frame->tf_x[dest_reg];
        size = frame->tf_x[size_reg];

        /*
         * Put the registers back in the original format suitable for a
         * prologue instruction, using the generic return routine from the
         * Arm ARM (DDI 0487I.a) rules CNTMJ and MWFQH.
         */
        if (esr & ISS_MOE_MEMINST) {
                /* SET* instruction */
                if (format_option == ISS_MOE_FORMAT_OPTION_A ||
                    format_option == ISS_MOE_FORMAT_OPTION_A2) {
                        /* Format is from Option A; forward set */
                        frame->tf_x[dest_reg] = dest + size;
                        frame->tf_x[size_reg] = -size;
                }
        } else {
                /* CPY* instruction */
                src_reg = (esr & ISS_MOE_SRCREG_MASK) >> ISS_MOE_SRCREG_SHIFT;
                src = frame->tf_x[src_reg];

                if (format_option == ISS_MOE_FORMAT_OPTION_B ||
                    format_option == ISS_MOE_FORMAT_OPTION_B2) {
                        /* Format is from Option B */
                        if (frame->tf_spsr & PSR_N) {
                                /* Backward copy */
                                frame->tf_x[dest_reg] = dest - size;
                                frame->tf_x[src_reg] = src + size;
                        }
                } else {
                        /* Format is from Option A */
                        if (frame->tf_x[size_reg] & (1UL << 63)) {
                                /* Forward copy */
                                frame->tf_x[dest_reg] = dest + size;
                                frame->tf_x[src_reg] = src + size;
                                frame->tf_x[size_reg] = -size;
                        }
                }
        }

        if (esr & ISS_MOE_FROM_EPILOGUE)
                frame->tf_elr -= 8;
        else
                frame->tf_elr -= 4;
}

/*
 * See the comment above data_abort().
 */
void NO_PERTHREAD_SSP
do_el1h_sync(struct thread *td, struct trapframe *frame)
{
        uint32_t exception;
        uint64_t esr, far;
        int dfsc;

        kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0);
        kmsan_mark(frame, sizeof(*frame), KMSAN_STATE_INITED);

        far = frame->tf_far;
        /* Read the esr register to get the exception details */
        esr = frame->tf_esr;
        exception = ESR_ELx_EXCEPTION(esr);

#ifdef KDTRACE_HOOKS
        if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, exception))
                return;
#endif

        CTR4(KTR_TRAP, "%s: exception=%lu, elr=0x%lx, esr=0x%lx",
            __func__, exception, frame->tf_elr, esr);

        /*
         * Enable debug exceptions if we aren't already handling one. They will
         * be masked again in the exception handler's epilogue.
         */
        switch (exception) {
        case EXCP_BRK:
        case EXCP_BRKPT_EL1:
        case EXCP_WATCHPT_EL1:
        case EXCP_SOFTSTP_EL1:
                break;
        default:
                dbg_enable();
                break;
        }

        switch (exception) {
        case EXCP_FP_SIMD:
        case EXCP_TRAP_FP:
#ifdef VFP
                if ((td->td_pcb->pcb_fpflags & PCB_FP_KERN) != 0) {
                        vfp_restore_state();
                } else
#endif
                {
                        print_registers(frame);
                        printf(" esr: 0x%.16lx\n", esr);
                        panic("VFP exception in the kernel");
                }
                break;
        case EXCP_INSN_ABORT:
        case EXCP_DATA_ABORT:
                dfsc = esr & ISS_DATA_DFSC_MASK;
                if (dfsc < nitems(abort_handlers) &&
                    abort_handlers[dfsc] != NULL) {
                        abort_handlers[dfsc](td, frame, esr, far, 0);
                } else {
                        print_registers(frame);
                        print_gp_register("far", far);
                        printf(" esr: 0x%.16lx\n", esr);
                        panic("Unhandled EL1 %s abort: 0x%x",
                            exception == EXCP_INSN_ABORT ? "instruction" :
                            "data", dfsc);
                }
                break;
        case EXCP_BRK:
#ifdef KDTRACE_HOOKS
                if ((esr & ESR_ELx_ISS_MASK) == 0x40d /* BRK_IMM16_VAL */ &&
                    dtrace_invop_jump_addr != NULL &&
                    dtrace_invop_jump_addr(frame) == 0)
                        break;
#endif
#ifdef KDB
                kdb_trap(exception, 0, frame);
#else
                panic("No debugger in kernel.");
#endif
                break;
        case EXCP_BRKPT_EL1:
        case EXCP_WATCHPT_EL1:
        case EXCP_SOFTSTP_EL1:
#ifdef KDB
                kdb_trap(exception, 0, frame);
#else
                panic("No debugger in kernel.");
#endif
                break;
        case EXCP_FPAC:
                /* We can see this if the authentication on PAC fails */
                print_registers(frame);
                print_gp_register("far", far);
                panic("FPAC kernel exception");
                break;
        case EXCP_UNKNOWN:
                print_registers(frame);
                print_gp_register("far", far);
                panic("Undefined instruction: %08x",
                    *(uint32_t *)frame->tf_elr);
                break;
        case EXCP_BTI:
                print_registers(frame);
                print_gp_register("far", far);
                panic("Branch Target exception");
                break;
        case EXCP_MOE:
                handle_moe(td, frame, esr);
                break;
        default:
                print_registers(frame);
                print_gp_register("far", far);
                panic("Unknown kernel exception 0x%x esr_el1 0x%lx", exception,
                    esr);
        }
}

void
do_el0_sync(struct thread *td, struct trapframe *frame)
{
        pcpu_bp_harden bp_harden;
        uint32_t exception;
        uint64_t esr, far;
        int dfsc;
        bool skip_userret;

        /* Check we have a sane environment when entering from userland */
        KASSERT((uintptr_t)get_pcpu() >= VM_MIN_KERNEL_ADDRESS,
            ("Invalid pcpu address from userland: %p (tpidr 0x%lx)",
             get_pcpu(), READ_SPECIALREG(tpidr_el1)));

        kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0);
        kmsan_mark(frame, sizeof(*frame), KMSAN_STATE_INITED);

        far = frame->tf_far;
        esr = frame->tf_esr;
        exception = ESR_ELx_EXCEPTION(esr);
        if (exception == EXCP_INSN_ABORT_L && far > VM_MAXUSER_ADDRESS) {
                /*
                 * Userspace may be trying to train the branch predictor to
                 * attack the kernel. If we are on a CPU affected by this
                 * call the handler to clear the branch predictor state.
                 */
                bp_harden = PCPU_GET(bp_harden);
                if (bp_harden != NULL)
                        bp_harden();
        }
        intr_enable();

        CTR4(KTR_TRAP, "%s: exception=%lu, elr=0x%lx, esr=0x%lx",
            __func__, exception, frame->tf_elr, esr);

        skip_userret = false;
        switch (exception) {
        case EXCP_FP_SIMD:
#ifdef VFP
                vfp_restore_state();
#else
                panic("VFP exception in userland");
#endif
                break;
        case EXCP_TRAP_FP:
#ifdef VFP
                fpe_trap(td, (void *)frame->tf_elr, esr);
#else
                panic("VFP exception in userland");
#endif
                break;
        case EXCP_SVE:
                /* Returns true if this thread can use SVE */
                if (!sve_restore_state(td))
                        call_trapsignal(td, SIGILL, ILL_ILLTRP,
                            (void *)frame->tf_elr, exception);
                break;
        case EXCP_SVC32:
        case EXCP_SVC64:
                skip_userret = svc_handler(td, frame);
                break;
        case EXCP_INSN_ABORT_L:
        case EXCP_DATA_ABORT_L:
        case EXCP_DATA_ABORT:
                dfsc = esr & ISS_DATA_DFSC_MASK;
                if (dfsc < nitems(abort_handlers) &&
                    abort_handlers[dfsc] != NULL)
                        abort_handlers[dfsc](td, frame, esr, far, 1);
                else {
                        print_registers(frame);
                        print_gp_register("far", far);
                        printf(" esr: 0x%.16lx\n", esr);
                        panic("Unhandled EL0 %s abort: 0x%x",
                            exception == EXCP_INSN_ABORT_L ? "instruction" :
                            "data", dfsc);
                }
                break;
        case EXCP_UNKNOWN:
                if (!undef_insn(frame))
                        call_trapsignal(td, SIGILL, ILL_ILLTRP, (void *)far,
                            exception);
                break;
        case EXCP_FPAC:
                call_trapsignal(td, SIGILL, ILL_ILLOPN, (void *)frame->tf_elr,
                    exception);
                break;
        case EXCP_SP_ALIGN:
                call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_sp,
                    exception);
                break;
        case EXCP_PC_ALIGN:
                call_trapsignal(td, SIGBUS, BUS_ADRALN, (void *)frame->tf_elr,
                    exception);
                break;
        case EXCP_BRKPT_EL0:
        case EXCP_BRK:
#ifdef COMPAT_FREEBSD32
        case EXCP_BRKPT_32:
#endif /* COMPAT_FREEBSD32 */
                call_trapsignal(td, SIGTRAP, TRAP_BRKPT, (void *)frame->tf_elr,
                    exception);
                break;
        case EXCP_WATCHPT_EL0:
                call_trapsignal(td, SIGTRAP, TRAP_TRACE, (void *)far,
                    exception);
                break;
        case EXCP_MSR:
                /*
                 * The CPU can raise EXCP_MSR when userspace executes an mrs
                 * instruction to access a special register userspace doesn't
                 * have access to.
                 */
                if (!undef_insn(frame))
                        call_trapsignal(td, SIGILL, ILL_PRVOPC,
                            (void *)frame->tf_elr, exception);
                break;
        case EXCP_SOFTSTP_EL0:
                PROC_LOCK(td->td_proc);
                if ((td->td_dbgflags & TDB_STEP) != 0) {
                        td->td_frame->tf_spsr &= ~PSR_SS;
                        td->td_pcb->pcb_flags &= ~PCB_SINGLE_STEP;
                        WRITE_SPECIALREG(mdscr_el1,
                            READ_SPECIALREG(mdscr_el1) & ~MDSCR_SS);
                }
                PROC_UNLOCK(td->td_proc);
                call_trapsignal(td, SIGTRAP, TRAP_TRACE,
                    (void *)frame->tf_elr, exception);
                break;
        case EXCP_BTI:
                call_trapsignal(td, SIGILL, ILL_ILLOPC, (void *)frame->tf_elr,
                    exception);
                break;
        case EXCP_MOE:
                handle_moe(td, frame, esr);
                break;
        default:
                call_trapsignal(td, SIGBUS, BUS_OBJERR, (void *)frame->tf_elr,
                    exception);
                break;
        }

        if (!skip_userret)
                userret(td, frame);
        KASSERT(
            (td->td_pcb->pcb_fpflags & ~(PCB_FP_USERMASK|PCB_FP_SVEVALID)) == 0,
            ("Kernel VFP flags set while entering userspace"));
        KASSERT(
            td->td_pcb->pcb_fpusaved == &td->td_pcb->pcb_fpustate,
            ("Kernel VFP state in use when entering userspace"));
}

/*
 * TODO: We will need to handle these later when we support ARMv8.2 RAS.
 */
void
do_serror(struct trapframe *frame)
{
        uint64_t esr, far;

        kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0);
        kmsan_mark(frame, sizeof(*frame), KMSAN_STATE_INITED);

        far = frame->tf_far;
        esr = frame->tf_esr;

        print_registers(frame);
        print_gp_register("far", far);
        printf(" esr: 0x%.16lx\n", esr);
        panic("Unhandled System Error");
}

void
unhandled_exception(struct trapframe *frame)
{
        uint64_t esr, far;

        kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0);
        kmsan_mark(frame, sizeof(*frame), KMSAN_STATE_INITED);

        far = frame->tf_far;
        esr = frame->tf_esr;

        print_registers(frame);
        print_gp_register("far", far);
        printf(" esr: 0x%.16lx\n", esr);
        panic("Unhandled exception");
}