/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 */
/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/kmem.h>
#include <sys/proc.h>
#include <sys/smp.h>
#include <sys/dtrace_impl.h>
#include <sys/dtrace_bsd.h>
#include <cddl/dev/dtrace/dtrace_cddl.h>
#include <machine/armreg.h>
#include <machine/clock.h>
#include <machine/frame.h>
#include <machine/trap.h>
#include <machine/vmparam.h>
#include <vm/pmap.h>

extern dtrace_id_t      dtrace_probeid_error;
extern int (*dtrace_invop_jump_addr)(struct trapframe *);
extern void dtrace_getnanotime(struct timespec *tsp);
extern void dtrace_getnanouptime(struct timespec *tsp);

int dtrace_invop(uintptr_t, struct trapframe *, uintptr_t);
void dtrace_invop_init(void);
void dtrace_invop_uninit(void);

typedef struct dtrace_invop_hdlr {
        int (*dtih_func)(uintptr_t, struct trapframe *, uintptr_t);
        struct dtrace_invop_hdlr *dtih_next;
} dtrace_invop_hdlr_t;

dtrace_invop_hdlr_t *dtrace_invop_hdlr;

int
dtrace_invop(uintptr_t addr, struct trapframe *frame, uintptr_t eax)
{
        struct thread *td;
        dtrace_invop_hdlr_t *hdlr;
        int rval;

        rval = 0;
        td = curthread;
        td->t_dtrace_trapframe = frame;
        for (hdlr = dtrace_invop_hdlr; hdlr != NULL; hdlr = hdlr->dtih_next)
                if ((rval = hdlr->dtih_func(addr, frame, eax)) != 0)
                        break;
        td->t_dtrace_trapframe = NULL;
        return (rval);
}

void
dtrace_invop_add(int (*func)(uintptr_t, struct trapframe *, uintptr_t))
{
        dtrace_invop_hdlr_t *hdlr;

        hdlr = kmem_alloc(sizeof (dtrace_invop_hdlr_t), KM_SLEEP);
        hdlr->dtih_func = func;
        hdlr->dtih_next = dtrace_invop_hdlr;
        dtrace_invop_hdlr = hdlr;
}

void
dtrace_invop_remove(int (*func)(uintptr_t, struct trapframe *, uintptr_t))
{
        dtrace_invop_hdlr_t *hdlr, *prev;

        hdlr = dtrace_invop_hdlr;
        prev = NULL;

        for (;;) {
                if (hdlr == NULL)
                        panic("attempt to remove non-existent invop handler");

                if (hdlr->dtih_func == func)
                        break;

                prev = hdlr;
                hdlr = hdlr->dtih_next;
        }

        if (prev == NULL) {
                ASSERT(dtrace_invop_hdlr == hdlr);
                dtrace_invop_hdlr = hdlr->dtih_next;
        } else {
                ASSERT(dtrace_invop_hdlr != hdlr);
                prev->dtih_next = hdlr->dtih_next;
        }

        kmem_free(hdlr, 0);
}

/*ARGSUSED*/
void
dtrace_toxic_ranges(void (*func)(uintptr_t base, uintptr_t limit))
{

        (*func)(0, (uintptr_t)VM_MIN_KERNEL_ADDRESS);
}

static uint64_t nsec_scale;

#define SCALE_SHIFT     25

/*
 * Choose scaling factors which let us convert a cntvct_el0 value to nanoseconds
 * without overflow, as in the amd64 implementation.
 *
 * Documentation for the ARM generic timer states that typical counter
 * frequencies are in the range 1Mhz-50Mhz; in ARMv9 the frequency is fixed at
 * 1GHz.  The lower bound of 1MHz forces the shift to be at most 25 bits.  At
 * that frequency, the calculation (hi * scale) << (32 - shift) will not
 * overflow for over 100 years, assuming that the counter value starts at 0 upon
 * boot.
 */
static void
dtrace_gethrtime_init(void *arg __unused)
{
        uint64_t freq;

        freq = READ_SPECIALREG(cntfrq_el0);
        nsec_scale = ((uint64_t)NANOSEC << SCALE_SHIFT) / freq;
}
SYSINIT(dtrace_gethrtime_init, SI_SUB_DTRACE, SI_ORDER_ANY,
    dtrace_gethrtime_init, NULL);

/*
 * DTrace needs a high resolution time function which can be called from a
 * probe context and guaranteed not to have instrumented with probes itself.
 *
 * Returns nanoseconds since some arbitrary point in time (likely SoC reset?).
 */
uint64_t
dtrace_gethrtime(void)
{
        uint64_t count, freq;
        uint32_t lo, hi;

        count = READ_SPECIALREG(cntvct_el0);
        lo = count;
        hi = count >> 32;
        return (((lo * nsec_scale) >> SCALE_SHIFT) +
            ((hi * nsec_scale) << (32 - SCALE_SHIFT)));
}

/*
 * Return a much lower resolution wallclock time based on the system clock
 * updated by the timer.  If needed, we could add a version interpolated from
 * the system clock as is the case with dtrace_gethrtime().
 */
uint64_t
dtrace_gethrestime(void)
{
        struct timespec current_time;

        dtrace_getnanotime(&current_time);

        return (current_time.tv_sec * 1000000000UL + current_time.tv_nsec);
}

/* Function to handle DTrace traps during probes. See arm64/arm64/trap.c */
int
dtrace_trap(struct trapframe *frame, u_int type)
{
        /*
         * A trap can occur while DTrace executes a probe. Before
         * executing the probe, DTrace blocks re-scheduling and sets
         * a flag in its per-cpu flags to indicate that it doesn't
         * want to fault. On returning from the probe, the no-fault
         * flag is cleared and finally re-scheduling is enabled.
         *
         * Check if DTrace has enabled 'no-fault' mode:
         *
         */

        if ((cpu_core[curcpu].cpuc_dtrace_flags & CPU_DTRACE_NOFAULT) != 0) {
                /*
                 * There are only a couple of trap types that are expected.
                 * All the rest will be handled in the usual way.
                 */
                switch (type) {
                case EXCP_DATA_ABORT:
                        /* Flag a bad address. */
                        cpu_core[curcpu].cpuc_dtrace_flags |= CPU_DTRACE_BADADDR;
                        cpu_core[curcpu].cpuc_dtrace_illval = frame->tf_far;

                        /*
                         * Offset the instruction pointer to the instruction
                         * following the one causing the fault.
                         */
                        frame->tf_elr += 4;
                        return (1);
                default:
                        /* Handle all other traps in the usual way. */
                        break;
                }
        }

        /* Handle the trap in the usual way. */
        return (0);
}

void
dtrace_probe_error(dtrace_state_t *state, dtrace_epid_t epid, int which,
    int fault, int fltoffs, uintptr_t illval)
{

        dtrace_probe(dtrace_probeid_error, (uint64_t)(uintptr_t)state,
            (uintptr_t)epid,
            (uintptr_t)which, (uintptr_t)fault, (uintptr_t)fltoffs);
}

static void
dtrace_load64(uint64_t *addr, struct trapframe *frame, u_int reg)
{

        KASSERT(reg <= 31, ("dtrace_load64: Invalid register %u", reg));
        if (reg < nitems(frame->tf_x))
                frame->tf_x[reg] = *addr;
        else if (reg == 30) /* lr */
                frame->tf_lr = *addr;
        /* Nothing to do for load to xzr */
}

static void
dtrace_store64(uint64_t *addr, struct trapframe *frame, u_int reg)
{

        KASSERT(reg <= 31, ("dtrace_store64: Invalid register %u", reg));
        if (reg < nitems(frame->tf_x))
                *addr = frame->tf_x[reg];
        else if (reg == 30) /* lr */
                *addr = frame->tf_lr;
        else if (reg == 31) /* xzr */
                *addr = 0;
}

static int
dtrace_invop_start(struct trapframe *frame)
{
        int data, invop, tmp;

        invop = dtrace_invop(frame->tf_elr, frame, frame->tf_x[0]);

        tmp = (invop & LDP_STP_MASK);
        if (tmp == STP_64 || tmp == LDP_64) {
                register_t arg1, arg2, *sp;
                int offs;

                sp = (register_t *)frame->tf_sp;
                data = invop;
                arg1 = (data >> ARG1_SHIFT) & ARG1_MASK;
                arg2 = (data >> ARG2_SHIFT) & ARG2_MASK;

                offs = (data >> OFFSET_SHIFT) & OFFSET_MASK;

                switch (tmp) {
                case STP_64:
                        if (offs >> (OFFSET_SIZE - 1))
                                sp -= (~offs & OFFSET_MASK) + 1;
                        else
                                sp += (offs);
                        dtrace_store64(sp + 0, frame, arg1);
                        dtrace_store64(sp + 1, frame, arg2);
                        break;
                case LDP_64:
                        dtrace_load64(sp + 0, frame, arg1);
                        dtrace_load64(sp + 1, frame, arg2);
                        if (offs >> (OFFSET_SIZE - 1))
                                sp -= (~offs & OFFSET_MASK) + 1;
                        else
                                sp += (offs);
                        break;
                default:
                        break;
                }

                /* Update the stack pointer and program counter to continue */
                frame->tf_sp = (register_t)sp;
                frame->tf_elr += INSN_SIZE;
                return (0);
        }

        if ((invop & SUB_MASK) == SUB_INSTR) {
                frame->tf_sp -= (invop >> SUB_IMM_SHIFT) & SUB_IMM_MASK;
                frame->tf_elr += INSN_SIZE;
                return (0);
        }

        if (invop == NOP_INSTR) {
                frame->tf_elr += INSN_SIZE;
                return (0);
        }

        if ((invop & B_MASK) == B_INSTR) {
                data = (invop & B_DATA_MASK);
                /* The data is the number of 4-byte words to change the pc */
                data *= 4;
                frame->tf_elr += data;
                return (0);
        }

        if (invop == RET_INSTR) {
                frame->tf_elr = frame->tf_lr;
                return (0);
        }

        return (-1);
}

void
dtrace_invop_init(void)
{

        dtrace_invop_jump_addr = dtrace_invop_start;
}

void
dtrace_invop_uninit(void)
{

        dtrace_invop_jump_addr = 0;
}