/*
 * 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 <vm/pmap.h>

#define DELAYBRANCH(x)  ((int)(x) < 0)

#define BIT_PC          15
#define BIT_LR          14
#define BIT_SP          13

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 = 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))
{

        /*
         * There are no ranges to exclude that are common to all 32-bit arm
         * platforms.  This function only needs to exclude ranges "... in
         * which it is impossible to recover from such a load after it has been
         * attempted." -- i.e., accessing within the range causes some sort
         * fault in the system which is not handled by the normal arm
         * exception-handling mechanisms.  If systems exist where that is the
         * case, a method to handle this functionality would have to be added to
         * the platform_if interface so that those systems could provide their
         * specific toxic range(s).
         */
}

/*
 * 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 boot.
 */
uint64_t
dtrace_gethrtime(void)
{
        struct  timespec curtime;

        dtrace_getnanouptime(&curtime);

        return (curtime.tv_sec * 1000000000UL + curtime.tv_nsec);

}

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 amd64/amd64/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) {
                /* Page fault. */
                case FAULT_ALIGN:
                        /* Flag a bad address. */
                        cpu_core[curcpu].cpuc_dtrace_flags |= CPU_DTRACE_BADADDR;
                        cpu_core[curcpu].cpuc_dtrace_illval = 0;

                        /*
                         * Offset the instruction pointer to the instruction
                         * following the one causing the fault.
                         */
                        frame->tf_pc += sizeof(int);
                        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 int
dtrace_invop_start(struct trapframe *frame)
{
        register_t *r0, *sp;
        int data, invop, reg, update_sp;

        invop = dtrace_invop(frame->tf_pc, frame, frame->tf_r0);
        switch (invop & DTRACE_INVOP_MASK) {
        case DTRACE_INVOP_PUSHM:
                sp = (register_t *)frame->tf_svc_sp;
                r0 = &frame->tf_r0;
                data = DTRACE_INVOP_DATA(invop);

                /*
                 * Store the pc, lr, and sp. These have their own
                 * entries in the struct.
                 */
                if (data & (1 << BIT_PC)) {
                        sp--;
                        *sp = frame->tf_pc;
                }
                if (data & (1 << BIT_LR)) {
                        sp--;
                        *sp = frame->tf_svc_lr;
                }
                if (data & (1 << BIT_SP)) {
                        sp--;
                        *sp = frame->tf_svc_sp;
                }

                /* Store the general registers */
                for (reg = 12; reg >= 0; reg--) {
                        if (data & (1 << reg)) {
                                sp--;
                                *sp = r0[reg];
                        }
                }

                /* Update the stack pointer and program counter to continue */
                frame->tf_svc_sp = (register_t)sp;
                frame->tf_pc += 4;
                break;
        case DTRACE_INVOP_POPM:
                sp = (register_t *)frame->tf_svc_sp;
                r0 = &frame->tf_r0;
                data = DTRACE_INVOP_DATA(invop);

                /* Read the general registers */
                for (reg = 0; reg <= 12; reg++) {
                        if (data & (1 << reg)) {
                                r0[reg] = *sp;
                                sp++;
                        }
                }

                /*
                 * Set the stack pointer. If we don't update it here we will
                 * need to update it at the end as the instruction would do
                 */
                update_sp = 1;
                if (data & (1 << BIT_SP)) {
                        frame->tf_svc_sp = *sp;
                        *sp++;
                        update_sp = 0;
                }

                /* Update the link register, we need to use the correct copy */
                if (data & (1 << BIT_LR)) {
                        frame->tf_svc_lr = *sp;
                        *sp++;
                }
                /*
                 * And the program counter. If it's not in the list skip over
                 * it when we return so to not hit this again.
                 */
                if (data & (1 << BIT_PC)) {
                        frame->tf_pc = *sp;
                        *sp++;
                } else
                        frame->tf_pc += 4;

                /* Update the stack pointer if we haven't already done so */
                if (update_sp)
                        frame->tf_svc_sp = (register_t)sp;
                break;
        case DTRACE_INVOP_B:
                data = DTRACE_INVOP_DATA(invop) & 0x00ffffff;
                /* Sign extend the data */
                if ((data & (1 << 23)) != 0)
                        data |= 0xff000000;
                /* The data is the number of 4-byte words to change the pc */
                data *= 4;
                data += 8;
                frame->tf_pc += data;
                break;
        default:
                return (-1);
                break;
        }

        return (0);
}

void dtrace_invop_init(void)
{
        dtrace_invop_jump_addr = dtrace_invop_start;
}

void dtrace_invop_uninit(void)
{
        dtrace_invop_jump_addr = 0;
}