/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2006 Peter Wemm
 * 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/cdefs.h>
#include "opt_pmap.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/sysctl.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>
#include <machine/vmparam.h>

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

static struct kerneldumpheader kdh;

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

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

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

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

/* Pat the watchdog approximately every 128MB of the dump. */
#define WDOG_DUMP_INTERVAL      (128 * 1024 * 1024)

static int
blk_write(struct dumperinfo *di, char *ptr, vm_paddr_t pa, size_t sz)
{
        size_t len;
        int error, i, 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("can't have both va and pa!\n");
                return (EINVAL);
        }
        if ((((uintptr_t)pa) % PAGE_SIZE) != 0) {
                printf("address not page aligned %p\n", ptr);
                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;
                progress -= len;

                dumpsys_pb_progress(len);
                if (progress <= wdog_next) {
                        wdog_kern_pat(WD_LASTVAL);
                        if (wdog_next > WDOG_DUMP_INTERVAL)
                                wdog_next -= WDOG_DUMP_INTERVAL;
                        else
                                wdog_next = 0;
                }

                if (ptr) {
                        error = dump_append(di, ptr, len);
                        if (error)
                                return (error);
                        ptr += len;
                        sz -= len;
                } else {
                        for (i = 0; i < len; i += PAGE_SIZE)
                                dump_va = pmap_kenter_temporary(pa + i, (i + fragsz) >> PAGE_SHIFT);
                        fragsz += len;
                        pa += len;
                        sz -= len;
                        if (fragsz == maxdumpsz) {
                                error = blk_flush(di);
                                if (error)
                                        return (error);
                        }
                }

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

        return (0);
}

/* A fake page table page, to avoid having to handle both 4K and 2M pages */
static pd_entry_t fakepd[NPDEPG];

int
cpu_minidumpsys(struct dumperinfo *di, const struct minidumpstate *state)
{
        uint32_t pmapsize;
        vm_offset_t va, kva_end;
        int error;
        uint64_t *pml4, *pdp, *pd, *pt, pa;
        uint64_t pdpe, pde, pte;
        int ii, j, k, n;
        int retry_count;
        struct minidumphdr mdhdr;
        struct msgbuf *mbp;

        retry_count = 0;
 retry:
        retry_count++;

        /* Snapshot the KVA upper bound in case it grows. */
        kva_end = MAX(KERNBASE + nkpt * NBPDR, 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.
         */
        pmapsize = 0;
        for (va = kva_layout.km_low; va < kva_end; ) {
                /*
                 * We always write a page, even if it is zero. Each
                 * page written corresponds to 1GB of space
                 */
                pmapsize += PAGE_SIZE;
                ii = pmap_pml4e_index(va);
                pml4 = (uint64_t *)PHYS_TO_DMAP(KPML4phys) + ii;
                pdp = (uint64_t *)PHYS_TO_DMAP(*pml4 & PG_FRAME);
                pdpe = atomic_load_64(&pdp[pmap_pdpe_index(va)]);
                if ((pdpe & PG_V) == 0) {
                        va += NBPDP;
                        continue;
                }

                /*
                 * 1GB page is represented as 512 2MB pages in a dump.
                 */
                if ((pdpe & PG_PS) != 0) {
                        va += NBPDP;
                        pa = pdpe & PG_PS_FRAME;
                        for (n = 0; n < NPDEPG * NPTEPG; n++) {
                                if (vm_phys_is_dumpable(pa))
                                        vm_page_dump_add(state->dump_bitset,
                                            pa);
                                pa += PAGE_SIZE;
                        }
                        continue;
                }

                pd = (uint64_t *)PHYS_TO_DMAP(pdpe & PG_FRAME);
                for (n = 0; n < NPDEPG; n++, va += NBPDR) {
                        pde = atomic_load_64(&pd[pmap_pde_index(va)]);

                        if ((pde & PG_V) == 0)
                                continue;

                        if ((pde & PG_PS) != 0) {
                                /* This is an entire 2M page. */
                                pa = pde & PG_PS_FRAME;
                                for (k = 0; k < NPTEPG; k++) {
                                        if (vm_phys_is_dumpable(pa))
                                                vm_page_dump_add(
                                                    state->dump_bitset, pa);
                                        pa += PAGE_SIZE;
                                }
                                continue;
                        }

                        pa = pde & PG_FRAME;
                        /* set bit for this PTE page */
                        if (vm_phys_is_dumpable(pa))
                                vm_page_dump_add(state->dump_bitset, pa);
                        /* and for each valid page in this 2MB block */
                        pt = (uint64_t *)PHYS_TO_DMAP(pde & PG_FRAME);
                        for (k = 0; k < NPTEPG; k++) {
                                pte = atomic_load_64(&pt[k]);
                                if ((pte & PG_V) == 0)
                                        continue;
                                pa = pte & PG_FRAME;
                                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;

        wdog_next = progress = dumpsize;
        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 = kva_layout.km_low;
        mdhdr.dmapbase = kva_layout.dmap_low;
        mdhdr.dmapend = kva_layout.dmap_high;
        mdhdr.dumpavailsize = round_page(sizeof(dump_avail));

        dump_init_header(di, &kdh, KERNELDUMPMAGIC, KERNELDUMP_AMD64_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 my header */
        bzero(&fakepd, sizeof(fakepd));
        bcopy(&mdhdr, &fakepd, sizeof(mdhdr));
        error = blk_write(di, (char *)&fakepd, 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(fakepd),
            "Large dump_avail not handled");
        bzero(&fakepd, sizeof(fakepd));
        memcpy(fakepd, dump_avail, sizeof(dump_avail));
        error = blk_write(di, (char *)fakepd, 0, PAGE_SIZE);
        if (error)
                goto fail;

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

        /* Dump kernel page directory pages */
        bzero(fakepd, sizeof(fakepd));
        for (va = kva_layout.km_low; va < kva_end; va += NBPDP) {
                ii = pmap_pml4e_index(va);
                pml4 = (uint64_t *)PHYS_TO_DMAP(KPML4phys) + ii;
                pdp = (uint64_t *)PHYS_TO_DMAP(*pml4 & PG_FRAME);
                pdpe = atomic_load_64(&pdp[pmap_pdpe_index(va)]);

                /* We always write a page, even if it is zero */
                if ((pdpe & PG_V) == 0) {
                        error = blk_write(di, (char *)&fakepd, 0, PAGE_SIZE);
                        if (error)
                                goto fail;
                        /* flush, in case we reuse fakepd in the same block */
                        error = blk_flush(di);
                        if (error)
                                goto fail;
                        continue;
                }

                /* 1GB page is represented as 512 2MB pages in a dump */
                if ((pdpe & PG_PS) != 0) {
                        /* PDPE and PDP have identical layout in this case */
                        fakepd[0] = pdpe;
                        for (j = 1; j < NPDEPG; j++)
                                fakepd[j] = fakepd[j - 1] + NBPDR;
                        error = blk_write(di, (char *)&fakepd, 0, PAGE_SIZE);
                        if (error)
                                goto fail;
                        /* flush, in case we reuse fakepd in the same block */
                        error = blk_flush(di);
                        if (error)
                                goto fail;
                        bzero(fakepd, sizeof(fakepd));
                        continue;
                }

                pa = pdpe & PG_FRAME;
                if (PHYS_IN_DMAP(pa) && vm_phys_is_dumpable(pa)) {
                        pd = (uint64_t *)PHYS_TO_DMAP(pa);
                        error = blk_write(di, (char *)pd, 0, PAGE_SIZE);
                } else {
                        /* Malformed pa, write the zeroed fakepd. */
                        error = blk_write(di, (char *)&fakepd, 0, PAGE_SIZE);
                }
                if (error)
                        goto fail;
                error = blk_flush(di);
                if (error)
                        goto fail;
        }

        /* 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;

        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 < 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 (about %lluMB were "
                    "needed this time).\n", (long long)dumpsize >> 20);
        } else
                printf("** DUMP FAILED (ERROR %d) **\n", error);
        return (error);
}