/*-
 * Copyright (c) 2019 Leandro Lupori
 * 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 ``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 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 <sys/types.h>
#include <sys/param.h>

#include <sys/cons.h>
#include <sys/kerneldump.h>
#include <sys/msgbuf.h>
#include <sys/proc.h>
#include <sys/sysctl.h>

#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_page.h>
#include <vm/vm_phys.h>
#include <vm/vm_dumpset.h>
#include <vm/pmap.h>

#include <machine/atomic.h>
#include <machine/dump.h>
#include <machine/md_var.h>
#include <machine/minidump.h>

/* Debugging stuff */
#define MINIDUMP_DEBUG  0
#if     MINIDUMP_DEBUG
#define dprintf(fmt, ...)       printf(fmt, ## __VA_ARGS__)
#define DBG(...)        __VA_ARGS__
static size_t total, dumptotal;
static void dump_total(const char *id, size_t sz);
#else
#define dprintf(fmt, ...)
#define DBG(...)
#define dump_total(...)
#endif

extern vm_offset_t __startkernel, __endkernel;

static int dump_retry_count = 5;
SYSCTL_INT(_machdep, OID_AUTO, dump_retry_count, CTLFLAG_RWTUN,
    &dump_retry_count, 0,
    "Number of times dump has to retry before bailing out");

static struct kerneldumpheader kdh;
static char pgbuf[PAGE_SIZE];

static size_t dumpsize;

/* Handle chunked writes. */
static size_t fragsz;

static void
pmap_kenter_temporary(vm_offset_t va, vm_paddr_t pa)
{
        pmap_kremove(va);
        pmap_kenter(va, pa);
}

static int
blk_flush(struct dumperinfo *di)
{
        int error;

        if (fragsz == 0)
                return (0);

        error = dump_append(di, crashdumpmap, fragsz);
        DBG(dumptotal += fragsz;)
        fragsz = 0;
        return (error);
}

static int
blk_write(struct dumperinfo *di, char *ptr, vm_paddr_t pa, size_t sz)
{
        size_t len, maxdumpsz;
        int error, i, c;

        maxdumpsz = MIN(di->maxiosize, MAXDUMPPGS * PAGE_SIZE);
        if (maxdumpsz == 0)     /* seatbelt */
                maxdumpsz = PAGE_SIZE;
        error = 0;
        if ((sz % PAGE_SIZE) != 0) {
                printf("Size not page aligned\n");
                return (EINVAL);
        }
        if (ptr != NULL && pa != 0) {
                printf("Can't have both va and pa!\n");
                return (EINVAL);
        }
        if ((pa % PAGE_SIZE) != 0) {
                printf("Address not page aligned 0x%lx\n", pa);
                return (EINVAL);
        }
        if (ptr != NULL) {
                /*
                 * If we're doing a virtual dump, flush any pre-existing
                 * pa pages
                 */
                error = blk_flush(di);
                if (error)
                        return (error);
        }
        while (sz) {
                len = maxdumpsz - fragsz;
                if (len > sz)
                        len = sz;

                dumpsys_pb_progress(len);

                if (ptr) {
                        error = dump_append(di, ptr, len);
                        if (error)
                                return (error);
                        DBG(dumptotal += len;)
                        ptr += len;
                } else {
                        for (i = 0; i < len; i += PAGE_SIZE)
                                pmap_kenter_temporary(
                                    (vm_offset_t)crashdumpmap + fragsz + i,
                                    pa + i);

                        fragsz += len;
                        pa += len;
                        if (fragsz == maxdumpsz) {
                                error = blk_flush(di);
                                if (error)
                                        return (error);
                        }
                }
                sz -= len;

                /* Check for user abort. */
                c = cncheckc();
                if (c == 0x03)
                        return (ECANCELED);
                if (c != -1)
                        printf(" (CTRL-C to abort) ");
        }

        return (0);
}

static int
dump_pmap(struct dumperinfo *di)
{
        void *ctx;
        char *buf;
        u_long nbytes;
        int error;

        ctx = dumpsys_dump_pmap_init(sizeof(pgbuf) / PAGE_SIZE);

        for (;;) {
                buf = dumpsys_dump_pmap(ctx, pgbuf, &nbytes);
                if (buf == NULL)
                        break;
                error = blk_write(di, buf, 0, nbytes);
                if (error)
                        return (error);
        }

        return (0);
}

int
cpu_minidumpsys(struct dumperinfo *di, const struct minidumpstate *state)
{
        vm_paddr_t pa;
        int error, retry_count;
        uint32_t pmapsize;
        struct minidumphdr mdhdr;
        struct msgbuf *mbp;

        retry_count = 0;
retry:
        retry_count++;
        fragsz = 0;
        DBG(total = dumptotal = 0;)

        /* Build set of dumpable pages from kernel pmap */
        pmapsize = dumpsys_scan_pmap(state->dump_bitset);
        if (pmapsize % PAGE_SIZE != 0) {
                printf("pmapsize not page aligned: 0x%x\n", pmapsize);
                return (EINVAL);
        }

        /* Calculate dump size */
        mbp = state->msgbufp;
        dumpsize = PAGE_SIZE;                           /* header */
        dumpsize += round_page(mbp->msg_size);
        dumpsize += round_page(sizeof(dump_avail));
        dumpsize += round_page(BITSET_SIZE(vm_page_dump_pages));
        dumpsize += pmapsize;
        VM_PAGE_DUMP_FOREACH(state->dump_bitset, pa) {
                /* Clear out undumpable pages now if needed */
                if (vm_phys_is_dumpable(pa))
                        dumpsize += PAGE_SIZE;
                else
                        vm_page_dump_drop(state->dump_bitset, pa);
        }
        dumpsys_pb_init(dumpsize);

        /* Initialize mdhdr */
        bzero(&mdhdr, sizeof(mdhdr));
        strcpy(mdhdr.magic, MINIDUMP_MAGIC);
        strncpy(mdhdr.mmu_name, pmap_mmu_name(), sizeof(mdhdr.mmu_name) - 1);
        mdhdr.version = MINIDUMP_VERSION;
        mdhdr.msgbufsize = mbp->msg_size;
        mdhdr.bitmapsize = round_page(BITSET_SIZE(vm_page_dump_pages));
        mdhdr.pmapsize = pmapsize;
        mdhdr.kernbase = VM_MIN_KERNEL_ADDRESS;
        mdhdr.kernend = VM_MAX_SAFE_KERNEL_ADDRESS;
        mdhdr.dmapbase = DMAP_BASE_ADDRESS;
        mdhdr.dmapend = DMAP_MAX_ADDRESS;
        mdhdr.hw_direct_map = hw_direct_map;
        mdhdr.startkernel = __startkernel;
        mdhdr.endkernel = __endkernel;
        mdhdr.dumpavailsize = round_page(sizeof(dump_avail));

        dump_init_header(di, &kdh, KERNELDUMPMAGIC, KERNELDUMP_POWERPC_VERSION,
            dumpsize);

        error = dump_start(di, &kdh);
        if (error)
                goto fail;

        printf("Dumping %lu out of %ju MB:", dumpsize >> 20,
            ptoa((uintmax_t)physmem) / 1048576);

        /* Dump minidump header */
        bzero(pgbuf, sizeof(pgbuf));
        memcpy(pgbuf, &mdhdr, sizeof(mdhdr));
        error = blk_write(di, pgbuf, 0, PAGE_SIZE);
        if (error)
                goto fail;
        dump_total("header", PAGE_SIZE);

        /* Dump msgbuf up front */
        error = blk_write(di, mbp->msg_ptr, 0, round_page(mbp->msg_size));
        dump_total("msgbuf", round_page(mbp->msg_size));

        /* Dump dump_avail */
        _Static_assert(sizeof(dump_avail) <= sizeof(pgbuf),
            "Large dump_avail not handled");
        bzero(pgbuf, sizeof(mdhdr));
        memcpy(pgbuf, dump_avail, sizeof(dump_avail));
        error = blk_write(di, pgbuf, 0, PAGE_SIZE);
        if (error)
                goto fail;
        dump_total("dump_avail", round_page(sizeof(dump_avail)));

        /* Dump bitmap */
        error = blk_write(di, (char *)vm_page_dump, 0,
            round_page(BITSET_SIZE(vm_page_dump_pages)));
        if (error)
                goto fail;
        dump_total("bitmap", round_page(BITSET_SIZE(vm_page_dump_pages)));

        /* Dump kernel page directory pages */
        error = dump_pmap(di);
        if (error)
                goto fail;
        dump_total("pmap", pmapsize);

        /* Dump memory chunks */
        VM_PAGE_DUMP_FOREACH(state->dump_bitset, pa) {
                error = blk_write(di, 0, pa, PAGE_SIZE);
                if (error)
                        goto fail;
        }

        error = blk_flush(di);
        if (error)
                goto fail;
        dump_total("mem_chunks", dumpsize - total);

        error = dump_finish(di, &kdh);
        if (error)
                goto fail;

        printf("\nDump complete\n");
        return (0);

fail:
        if (error < 0)
                error = -error;

        printf("\n");
        if (error == ENOSPC) {
                printf("Dump map grown while dumping. ");
                if (retry_count < dump_retry_count) {
                        printf("Retrying...\n");
                        goto retry;
                }
                printf("Dump failed.\n");
        } else if (error == ECANCELED)
                printf("Dump aborted\n");
        else if (error == E2BIG)
                printf("Dump failed. Partition too small.\n");
        else
                printf("** DUMP FAILED (ERROR %d) **\n", error);
        return (error);
}

#if     MINIDUMP_DEBUG
static void
dump_total(const char *id, size_t sz)
{
        total += sz;
        dprintf("\n%s=%08lx/%08lx/%08lx\n",
                id, sz, total, dumptotal);
}
#endif