/*-
 * Copyright (c) 2006 Peter Wemm
 * Copyright (c) 2015 The FreeBSD Foundation
 * All rights reserved.
 * Copyright (c) 2019 Mitchell Horne
 *
 * 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/cdefs.h>
#include "opt_watchdog.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/cons.h>
#include <sys/kernel.h>
#include <sys/kerneldump.h>
#include <sys/msgbuf.h>
#include <sys/watchdog.h>
#include <sys/vmmeter.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/elf.h>
#include <machine/md_var.h>
#include <machine/minidump.h>

CTASSERT(sizeof(struct kerneldumpheader) == 512);

static struct kerneldumpheader kdh;

/* Handle chunked writes. */
static size_t fragsz;
static void *dump_va;
static size_t dumpsize;

static uint64_t tmpbuffer[PAGE_SIZE / sizeof(uint64_t)];

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

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

        error = dump_append(di, dump_va, fragsz);
        fragsz = 0;
        return (error);
}

/*
 * Write a block of data to the dump file.
 *
 * Caller can provide data through a pointer or by specifying its
 * physical address.
 *
 * XXX writes using pa should be no larger than PAGE_SIZE.
 */
static int
blk_write(struct dumperinfo *di, char *ptr, vm_paddr_t pa, size_t sz)
{
        size_t len;
        int error, c;
        u_int maxdumpsz;

        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("cant have both va and pa!\n");
                return (EINVAL);
        }
        if ((((uintptr_t)pa) % PAGE_SIZE) != 0) {
                printf("address not page aligned %#lx\n", (uintptr_t)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 != 0)
                        return (error);
        }
        while (sz) {
                len = maxdumpsz - fragsz;
                if (len > sz)
                        len = sz;

                dumpsys_pb_progress(len);
                wdog_kern_pat(WD_LASTVAL);

                if (ptr) {
                        error = dump_append(di, ptr, len);
                        if (error != 0)
                                return (error);
                        ptr += len;
                        sz -= len;
                } else {
                        dump_va = (void *)PHYS_TO_DMAP(pa);
                        fragsz += len;
                        pa += len;
                        sz -= len;
                        error = blk_flush(di);
                        if (error != 0)
                                return (error);
                }

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

        return (0);
}

int
cpu_minidumpsys(struct dumperinfo *di, const struct minidumpstate *state)
{
        pd_entry_t *l1, *l2, l2e;
        pt_entry_t *l3, l3e;
        struct minidumphdr mdhdr;
        struct msgbuf *mbp;
        uint32_t pmapsize;
        vm_offset_t va, kva_max;
        vm_paddr_t pa;
        int error;
        int i;
        int retry_count;

        retry_count = 0;
retry:
        retry_count++;
        error = 0;
        pmapsize = 0;

        /* Snapshot the KVA upper bound in case it grows. */
        kva_max = kernel_vm_end;

        /*
         * Walk the kernel page table pages, setting the active entries in the
         * dump bitmap.
         *
         * NB: for a live dump, we may be racing with updates to the page
         * tables, so care must be taken to read each entry only once.
         */
        for (va = VM_MIN_KERNEL_ADDRESS; va < kva_max; va += L2_SIZE) {
                pmapsize += PAGE_SIZE;
                if (!pmap_get_tables(pmap_kernel(), va, &l1, &l2, &l3))
                        continue;

                /* We should always be using the l2 table for kvm */
                if (l2 == NULL)
                        continue;

                /* l2 may be a superpage */
                l2e = atomic_load_64(l2);
                if ((l2e & PTE_RWX) != 0) {
                        pa = (l2e >> PTE_PPN1_S) << L2_SHIFT;
                        for (i = 0; i < Ln_ENTRIES; i++, pa += PAGE_SIZE) {
                                if (vm_phys_is_dumpable(pa))
                                        vm_page_dump_add(state->dump_bitset,
                                            pa);
                        }
                } else {
                        for (i = 0; i < Ln_ENTRIES; i++) {
                                l3e = atomic_load_64(&l3[i]);
                                if ((l3e & PTE_V) == 0)
                                        continue;
                                pa = (l3e >> PTE_PPN0_S) * PAGE_SIZE;
                                if (PHYS_IN_DMAP(pa) && vm_phys_is_dumpable(pa))
                                        vm_page_dump_add(state->dump_bitset,
                                            pa);
                        }
                }
        }

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

        dumpsys_pb_init(dumpsize);

        /* Initialize mdhdr */
        bzero(&mdhdr, sizeof(mdhdr));
        strcpy(mdhdr.magic, MINIDUMP_MAGIC);
        mdhdr.version = MINIDUMP_VERSION;
        mdhdr.msgbufsize = mbp->msg_size;
        mdhdr.bitmapsize = round_page(BITSET_SIZE(vm_page_dump_pages));
        mdhdr.pmapsize = pmapsize;
        mdhdr.kernbase = KERNBASE;
        mdhdr.dmapphys = DMAP_MIN_PHYSADDR;
        mdhdr.dmapbase = DMAP_MIN_ADDRESS;
        mdhdr.dmapend = DMAP_MAX_ADDRESS;
        mdhdr.dumpavailsize = round_page(sizeof(dump_avail));

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

        error = dump_start(di, &kdh);
        if (error != 0)
                goto fail;

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

        /* Dump minidump header */
        bzero(&tmpbuffer, sizeof(tmpbuffer));
        bcopy(&mdhdr, &tmpbuffer, sizeof(mdhdr));
        error = blk_write(di, (char *)&tmpbuffer, 0, PAGE_SIZE);
        if (error)
                goto fail;

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

        /* Dump dump_avail */
        _Static_assert(sizeof(dump_avail) <= sizeof(tmpbuffer),
            "Large dump_avail not handled");
        bzero(tmpbuffer, sizeof(tmpbuffer));
        memcpy(tmpbuffer, dump_avail, sizeof(dump_avail));
        error = blk_write(di, (char *)&tmpbuffer, 0, PAGE_SIZE);
        if (error)
                goto fail;

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

        /* Dump kernel page directory pages */
        bzero(&tmpbuffer, sizeof(tmpbuffer));
        for (va = VM_MIN_KERNEL_ADDRESS; va < kva_max; va += L2_SIZE) {
                if (!pmap_get_tables(pmap_kernel(), va, &l1, &l2, &l3)) {
                        /* We always write a page, even if it is zero */
                        error = blk_write(di, (char *)&tmpbuffer, 0, PAGE_SIZE);
                        if (error)
                                goto fail;
                        /* Flush, in case we reuse tmpbuffer in the same block */
                        error = blk_flush(di);
                        if (error)
                                goto fail;
                        continue;
                }

                l2e = atomic_load_64(l2);
                if ((l2e & PTE_RWX) != 0) {
                        /* Generate fake l3 entries based on the l2 superpage */
                        for (i = 0; i < Ln_ENTRIES; i++) {
                                tmpbuffer[i] = (l2e | (i << PTE_PPN0_S));
                        }
                        /* We always write a page, even if it is zero */
                        error = blk_write(di, (char *)&tmpbuffer, 0, PAGE_SIZE);
                        if (error)
                                goto fail;
                        /* Flush, in case we reuse tmpbuffer in the same block */
                        error = blk_flush(di);
                        if (error)
                                goto fail;
                        bzero(&tmpbuffer, sizeof(tmpbuffer));
                } else {
                        pa = (l2e >> PTE_PPN0_S) * PAGE_SIZE;

                        /*
                         * We always write a page, even if it is zero. If pa
                         * is malformed, write the zeroed tmpbuffer.
                         */
                        if (PHYS_IN_DMAP(pa) && vm_phys_is_dumpable(pa))
                                error = blk_write(di, NULL, pa, PAGE_SIZE);
                        else
                                error = blk_write(di, (char *)&tmpbuffer, 0,
                                    PAGE_SIZE);
                        if (error)
                                goto fail;
                }
        }

        /* Dump memory chunks */
        /* XXX cluster it up and use blk_dump() */
        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;

        error = dump_finish(di, &kdh);
        if (error != 0)
                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 < 5) {
                        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 (about %lluMB were "
                    "needed this time).\n", (long long)dumpsize >> 20);
        } else
                printf("** DUMP FAILED (ERROR %d) **\n", error);
        return (error);
}