/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */

/*
 * Copyright (c) 2015, Joyent, Inc.  All rights reserved.
 */

#include <sys/mdb_modapi.h>
#include <sys/time.h>
#include <sys/mem.h>

typedef struct kmemlog_walk {
        uintptr_t kmlw_addr;
        mm_logentry_t *kmlw_entries;
        int kmlw_nentries;
        int kmlw_entry;
        int kmlw_oldest;
} kmemlog_walk_t;

static int
kmemlog_walk_init(mdb_walk_state_t *wsp)
{
        kmemlog_walk_t *kw;
        GElf_Sym sym;

        if (mdb_lookup_by_name("mm_kmemlog", &sym) != 0) {
                mdb_warn("couldn't find symbol 'mm_kmemlog'");
                return (WALK_ERR);
        }

        kw = mdb_zalloc(sizeof (kmemlog_walk_t), UM_SLEEP);
        kw->kmlw_entries = mdb_zalloc(sym.st_size, UM_SLEEP);
        kw->kmlw_addr = sym.st_value;

        if (mdb_vread(kw->kmlw_entries, sym.st_size, sym.st_value) == -1) {
                mdb_warn("couldn't read log at %p", sym.st_value);
                mdb_free(kw->kmlw_entries, sym.st_size);
                mdb_free(kw, sizeof (kmemlog_walk_t));
                return (WALK_ERR);
        }

        kw->kmlw_nentries = sym.st_size / sizeof (mm_logentry_t);

        mdb_readvar(&kw->kmlw_entry, "mm_kmemlogent");
        kw->kmlw_oldest = kw->kmlw_entry;
        wsp->walk_data = kw;

        return (WALK_NEXT);
}

static int
kmemlog_walk_step(mdb_walk_state_t *wsp)
{
        kmemlog_walk_t *kw = wsp->walk_data;
        mm_logentry_t *ent;
        int rval = WALK_NEXT;

        ent = &kw->kmlw_entries[kw->kmlw_entry];

        if (++kw->kmlw_entry == kw->kmlw_nentries)
                kw->kmlw_entry = 0;

        if (ent->mle_hrtime != 0) {
                rval = wsp->walk_callback(kw->kmlw_addr + ((uintptr_t)ent -
                    (uintptr_t)kw->kmlw_entries), ent, wsp->walk_cbdata);
        }

        if (rval == WALK_NEXT && kw->kmlw_entry == kw->kmlw_oldest)
                return (WALK_DONE);

        return (rval);
}

static void
kmemlog_walk_fini(mdb_walk_state_t *wsp)
{
        kmemlog_walk_t *kw = wsp->walk_data;

        mdb_free(kw->kmlw_entries, kw->kmlw_nentries * sizeof (mm_logentry_t));
        mdb_free(kw, sizeof (kmemlog_walk_t));
}

static int
kmemlog(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
{
        mm_logentry_t ent;

        if (!(flags & DCMD_ADDRSPEC)) {
                if (mdb_walk_dcmd("kmemlog", "kmemlog", argc, argv) == -1) {
                        mdb_warn("can't walk 'kmemlog'");
                        return (DCMD_ERR);
                }
                return (DCMD_OK);
        }

        if (DCMD_HDRSPEC(flags)) {
                mdb_printf("%?s %-20s %?s %5s %s\n",
                    "ADDR", "TIME", "VADDR", "PID", "PSARGS");
        }

        if (mdb_vread(&ent, sizeof (ent), addr) == -1) {
                mdb_warn("can't read mm_logentry_t at %p", addr);
                return (DCMD_ERR);
        }

        mdb_printf("%?p %-20Y %?p %5d %s\n",
            addr, ent.mle_hrestime.tv_sec, ent.mle_vaddr, ent.mle_pid,
            ent.mle_psargs);

        return (DCMD_OK);
}

static const mdb_dcmd_t dcmds[] = {
        { "kmemlog", NULL, "print log of writes via /dev/kmem", kmemlog },
        { NULL }
};

static const mdb_walker_t walkers[] = {
        { "kmemlog", "walk entries in /dev/kmem write log",
                kmemlog_walk_init, kmemlog_walk_step, kmemlog_walk_fini },
        { NULL }
};

static const mdb_modinfo_t modinfo = {
        MDB_API_VERSION, dcmds, walkers
};

const mdb_modinfo_t *
_mdb_init(void)
{
        return (&modinfo);
}