/*
 * 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/clock.h>
#include <machine/frame.h>
#include <machine/trap.h>
#include <vm/pmap.h>

#define DELAYBRANCH(x)  ((int)(x) < 0)
                
extern dtrace_id_t      dtrace_probeid_error;
extern int (*dtrace_invop_jump_addr)(struct trapframe *);

extern void dtrace_getnanotime(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 arg0)
{
        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, arg0)) != 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))
{
        /*
         * No toxic regions?
         */
}

static int64_t  tgt_cpu_tsc;
static int64_t  hst_cpu_tsc;
static int64_t  timebase_skew[MAXCPU];
static uint64_t nsec_scale;

/* See below for the explanation of this macro. */
/* This is taken from the amd64 dtrace_subr, to provide a synchronized timer
 * between multiple processors in dtrace.  Since PowerPC Timebases can be much
 * lower than x86, the scale shift is 26 instead of 28, allowing for a 15.63MHz
 * timebase.
 */
#define SCALE_SHIFT     26

static void
dtrace_gethrtime_init_cpu(void *arg)
{
        uintptr_t cpu = (uintptr_t) arg;

        if (cpu == curcpu)
                tgt_cpu_tsc = mftb();
        else
                hst_cpu_tsc = mftb();
}

static void
dtrace_gethrtime_init(void *arg)
{
        struct pcpu *pc;
        uint64_t tb_f;
        cpuset_t map;
        int i;

        tb_f = cpu_tickrate();

        /*
         * The following line checks that nsec_scale calculated below
         * doesn't overflow 32-bit unsigned integer, so that it can multiply
         * another 32-bit integer without overflowing 64-bit.
         * Thus minimum supported Timebase frequency is 15.63MHz.
         */
        KASSERT(tb_f > (NANOSEC >> (32 - SCALE_SHIFT)), ("Timebase frequency is too low"));

        /*
         * We scale up NANOSEC/tb_f ratio to preserve as much precision
         * as possible.
         * 2^26 factor was chosen quite arbitrarily from practical
         * considerations:
         * - it supports TSC frequencies as low as 15.63MHz (see above);
         */
        nsec_scale = ((uint64_t)NANOSEC << SCALE_SHIFT) / tb_f;

        /* The current CPU is the reference one. */
        sched_pin();
        timebase_skew[curcpu] = 0;
        CPU_FOREACH(i) {
                if (i == curcpu)
                        continue;

                pc = pcpu_find(i);
                CPU_SETOF(PCPU_GET(cpuid), &map);
                CPU_SET(pc->pc_cpuid, &map);

                smp_rendezvous_cpus(map, NULL,
                    dtrace_gethrtime_init_cpu,
                    smp_no_rendezvous_barrier, (void *)(uintptr_t) i);

                timebase_skew[i] = tgt_cpu_tsc - hst_cpu_tsc;
        }
        sched_unpin();
}
#ifdef EARLY_AP_STARTUP
SYSINIT(dtrace_gethrtime_init, SI_SUB_DTRACE, SI_ORDER_ANY,
    dtrace_gethrtime_init, NULL);
#else
SYSINIT(dtrace_gethrtime_init, SI_SUB_SMP, SI_ORDER_ANY, dtrace_gethrtime_init,
    NULL);
#endif

/*
 * 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)
{
        uint64_t timebase;
        uint32_t lo;
        uint32_t hi;

        /*
         * We split timebase value into lower and higher 32-bit halves and separately
         * scale them with nsec_scale, then we scale them down by 2^28
         * (see nsec_scale calculations) taking into account 32-bit shift of
         * the higher half and finally add.
         */
        timebase = mftb() - timebase_skew[curcpu];
        lo = timebase;
        hi = timebase >> 32;
        return (((lo * nsec_scale) >> SCALE_SHIFT) +
            ((hi * nsec_scale) << (32 - SCALE_SHIFT)));
}

uint64_t
dtrace_gethrestime(void)
{
        struct      timespec curtime;

        dtrace_getnanotime(&curtime);

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

/* Function to handle DTrace traps during probes. See powerpc/powerpc/trap.c */
int
dtrace_trap(struct trapframe *frame, u_int type)
{
        uint16_t nofault;

        /*
         * 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:
         */
        sched_pin();
        nofault = cpu_core[curcpu].cpuc_dtrace_flags & CPU_DTRACE_NOFAULT;
        sched_unpin();
        if (nofault) {
                KASSERT((frame->srr1 & PSL_EE) == 0, ("interrupts enabled"));
                /*
                 * 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 EXC_DSI:
                case EXC_DSE:
                        /* Flag a bad address. */
                        cpu_core[curcpu].cpuc_dtrace_flags |= CPU_DTRACE_BADADDR;
                        cpu_core[curcpu].cpuc_dtrace_illval = frame->dar;

                        /*
                         * Offset the instruction pointer to the instruction
                         * following the one causing the fault.
                         */
                        frame->srr0 += sizeof(int);
                        return (1);
                case EXC_ISI:
                case EXC_ISE:
                        /* Flag a bad address. */
                        cpu_core[curcpu].cpuc_dtrace_flags |= CPU_DTRACE_BADADDR;
                        cpu_core[curcpu].cpuc_dtrace_illval = frame->srr0;

                        /*
                         * Offset the instruction pointer to the instruction
                         * following the one causing the fault.
                         */
                        frame->srr0 += 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)
{

        switch (dtrace_invop(frame->srr0, frame, frame->fixreg[3])) {
        case DTRACE_INVOP_JUMP:
                break;
        case DTRACE_INVOP_BCTR:
                frame->srr0 = frame->ctr;
                break;
        case DTRACE_INVOP_BLR:
                frame->srr0 = frame->lr;
                break;
        case DTRACE_INVOP_MFLR_R0:
                frame->fixreg[0] = frame->lr;
                frame->srr0 = frame->srr0 + 4;
                break;
        default:
                return (-1);
        }
        return (0);
}

void dtrace_invop_init(void)
{
        dtrace_invop_jump_addr = dtrace_invop_start;
}

void dtrace_invop_uninit(void)
{
        dtrace_invop_jump_addr = 0;
}