/*-
 * Copyright (c) 2004 Marcel Moolenaar
 * Copyright (c) 2001 Doug Rabson
 * Copyright (c) 2016 The FreeBSD Foundation
 * All rights reserved.
 *
 * Portions of this software were developed by Konstantin Belousov
 * under sponsorship from the FreeBSD Foundation.
 *
 * 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
 *
 * $FreeBSD: head/sys/amd64/amd64/efirt.c 307391 2016-10-16 06:07:43Z kib $
 */

#include <sys/param.h>
#include <sys/efi.h>
#include <sys/eventhandler.h>
#include <sys/kernel.h>
#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/proc.h>
#include <sys/reboot.h>
#include <sys/sched.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/thread.h>
#include <sys/globaldata.h>

#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_param.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#include <vm/vm_extern.h>

#include <vm/vm_page2.h>

#include <machine/efi.h>
#include <machine/metadata.h>
#include <machine/md_var.h>
#include <machine/smp.h>
#include <machine/vmparam.h>

static struct efi_systbl *efi_systbl;
static struct efi_cfgtbl *efi_cfgtbl;
static struct efi_rt *efi_runtime;

static int efi_status2err[25] = {
        0,              /* EFI_SUCCESS */
        ENOEXEC,        /* EFI_LOAD_ERROR */
        EINVAL,         /* EFI_INVALID_PARAMETER */
        ENOSYS,         /* EFI_UNSUPPORTED */
        EMSGSIZE,       /* EFI_BAD_BUFFER_SIZE */
        EOVERFLOW,      /* EFI_BUFFER_TOO_SMALL */
        EBUSY,          /* EFI_NOT_READY */
        EIO,            /* EFI_DEVICE_ERROR */
        EROFS,          /* EFI_WRITE_PROTECTED */
        EAGAIN,         /* EFI_OUT_OF_RESOURCES */
        EIO,            /* EFI_VOLUME_CORRUPTED */
        ENOSPC,         /* EFI_VOLUME_FULL */
        ENXIO,          /* EFI_NO_MEDIA */
        ESTALE,         /* EFI_MEDIA_CHANGED */
        ENOENT,         /* EFI_NOT_FOUND */
        EACCES,         /* EFI_ACCESS_DENIED */
        ETIMEDOUT,      /* EFI_NO_RESPONSE */
        EADDRNOTAVAIL,  /* EFI_NO_MAPPING */
        ETIMEDOUT,      /* EFI_TIMEOUT */
        EDOOFUS,        /* EFI_NOT_STARTED */
        EALREADY,       /* EFI_ALREADY_STARTED */
        ECANCELED,      /* EFI_ABORTED */
        EPROTO,         /* EFI_ICMP_ERROR */
        EPROTO,         /* EFI_TFTP_ERROR */
        EPROTO          /* EFI_PROTOCOL_ERROR */
};

static MALLOC_DEFINE(M_EFI, "efi", "EFI BIOS");

static int
efi_status_to_errno(efi_status status)
{
        u_long code;

        code = status & 0x3ffffffffffffffful;
        return (code < nitems(efi_status2err) ? efi_status2err[code] : EDOOFUS);
}

static struct lock efi_lock;
static struct lock resettodr_lock;
static mcontext_t efi_ctx;
static struct vmspace *efi_savevm;
static struct vmspace *efi_vmspace;
static vm_object_t efi_obj;
static struct efi_md *efi_map;
static int efi_ndesc;
static int efi_descsz;

static void
efi_destroy_1t1_map(void)
{
        vm_object_t obj;
        vm_page_t m;

        if ((obj = efi_obj) != NULL) {
                efi_obj = NULL;
                vm_object_hold(obj);
                vm_object_reference_locked(obj);        /* match deallocate */
        }
        if (efi_vmspace) {
                pmap_remove_pages(vmspace_pmap(efi_vmspace),
                                  VM_MIN_USER_ADDRESS, VM_MAX_USER_ADDRESS);
                vm_map_remove(&efi_vmspace->vm_map,
                              VM_MIN_USER_ADDRESS,
                              VM_MAX_USER_ADDRESS);
                vmspace_rel(efi_vmspace);
                efi_vmspace = NULL;
        }
        if (obj) {
                while ((m = RB_ROOT(&obj->rb_memq)) != NULL) {
                        vm_page_busy_wait(m, FALSE, "efipg");
                        vm_page_unwire(m, 1);
                        vm_page_flag_clear(m, PG_MAPPED | PG_WRITEABLE);
                        cdev_pager_free_page(obj, m);
                        kfree(m, M_EFI);
                }
                vm_object_drop(obj);
                vm_object_deallocate(obj);
        }
}

static int
efi_pg_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
            vm_ooffset_t foff, struct ucred *cred, u_short *color)
{
        *color = 0;
        return 0;
}

static void
efi_pg_dtor(void *handle)
{
}

static int
efi_pg_fault(vm_object_t obj, vm_ooffset_t offset, int prot, vm_page_t *mres)
{
        vm_page_t m;

        m = *mres;
        if ((m->flags & PG_FICTITIOUS) == 0) {
                *mres = NULL;
                vm_page_remove(m);
                vm_page_free(m);
                m = NULL;
        }
        if (m == NULL) {
                kprintf("efi_pg_fault: unmapped pg @%016jx\n", offset);
                return VM_PAGER_ERROR;
        }

        /*
         * Shouldn't get hit, we pre-loaded all the pages.
         */
        kprintf("efi_pg_fault: ok %p/%p @%016jx m=%016jx,%016jx\n",
                obj, efi_obj, offset, m->pindex, m->phys_addr);

        return VM_PAGER_OK;
}

static struct cdev_pager_ops efi_pager_ops = {
        .cdev_pg_fault  = efi_pg_fault,
        .cdev_pg_ctor   = efi_pg_ctor,
        .cdev_pg_dtor   = efi_pg_dtor
};

static bool
efi_create_1t1_map(struct efi_md *map, int ndesc, int descsz)
{
        vm_page_t m;
        struct efi_md *p;
        int i;
        int count;
        int result;

        efi_map = map;
        efi_ndesc = ndesc;
        efi_descsz = descsz;

        /*
         * efi_obj is ref'd by cdev_pager_allocate
         */
        efi_vmspace = vmspace_alloc(VM_MIN_USER_ADDRESS, VM_MAX_USER_ADDRESS);
        pmap_pinit2(vmspace_pmap(efi_vmspace));
        efi_obj = cdev_pager_allocate(NULL, OBJT_MGTDEVICE, &efi_pager_ops,
                                  VM_MAX_USER_ADDRESS,
                                  VM_PROT_READ | VM_PROT_WRITE,
                                  0, proc0.p_ucred);
        vm_object_hold(efi_obj);

        count = vm_map_entry_reserve(MAP_RESERVE_COUNT);
        vm_map_lock(&efi_vmspace->vm_map);
        result = vm_map_insert(&efi_vmspace->vm_map, &count, efi_obj, NULL,
                              0, NULL,
                              0, VM_MAX_USER_ADDRESS,
                              VM_MAPTYPE_NORMAL,
                              VM_SUBSYS_EFI,
                              VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE,
                              VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE,
                              0);
        vm_map_unlock(&efi_vmspace->vm_map);
        if (result != KERN_SUCCESS)
                goto fail;

        for (i = 0, p = map;
             i < ndesc; i++, p = efi_next_descriptor(p, descsz)) {
                vm_offset_t va;
                uint64_t idx;
                int mode;

                if ((p->md_attr & EFI_MD_ATTR_RT) == 0)
                        continue;
                if (p->md_virt != NULL) {
                        if (bootverbose)
                                kprintf("EFI Runtime entry %d is mapped\n", i);
                        goto fail;
                }
                if ((p->md_phys & EFI_PAGE_MASK) != 0) {
                        if (bootverbose)
                                kprintf("EFI Runtime entry %d is not aligned\n",
                                    i);
                        goto fail;
                }
                if (p->md_phys + p->md_pages * EFI_PAGE_SIZE < p->md_phys ||
                    p->md_phys + p->md_pages * EFI_PAGE_SIZE >=
                    VM_MAX_USER_ADDRESS) {
                        kprintf("EFI Runtime entry %d is not in mappable for RT:"
                            "base %#016jx %#jx pages\n",
                            i, (uintmax_t)p->md_phys,
                            (uintmax_t)p->md_pages);
                        goto fail;
                }

                if ((p->md_attr & EFI_MD_ATTR_WB) != 0)
                        mode = VM_MEMATTR_WRITE_BACK;
                else if ((p->md_attr & EFI_MD_ATTR_WT) != 0)
                        mode = VM_MEMATTR_WRITE_THROUGH;
                else if ((p->md_attr & EFI_MD_ATTR_WC) != 0)
                        mode = VM_MEMATTR_WRITE_COMBINING;
                else if ((p->md_attr & EFI_MD_ATTR_WP) != 0)
                        mode = VM_MEMATTR_WRITE_PROTECTED;
                else if ((p->md_attr & EFI_MD_ATTR_UC) != 0)
                        mode = VM_MEMATTR_UNCACHEABLE;
                else {
                        if (bootverbose)
                                kprintf("EFI Runtime entry %d mapping "
                                    "attributes unsupported\n", i);
                        mode = VM_MEMATTR_UNCACHEABLE;
                }

                if (bootverbose) {
                        kprintf("efirt: map %016jx-%016jx\n",
                                p->md_phys,
                                p->md_phys + IDX_TO_OFF(p->md_pages));
                }

                for (va = p->md_phys, idx = 0; idx < p->md_pages; idx++,
                    va += PAGE_SIZE) {
                        m = kmalloc(sizeof(*m), M_EFI, M_WAITOK | M_ZERO);
                        /*m->flags |= PG_WRITEABLE;*/
                        vm_page_initfake(m, va, mode);  /* va is phys addr */
                        m->valid = VM_PAGE_BITS_ALL;
                        m->dirty = m->valid;
                        vm_page_insert(m, efi_obj, OFF_TO_IDX(va));
                        vm_page_wakeup(m);
                }
        }
        vm_object_drop(efi_obj);
        vm_map_entry_release(count);

        return true;

fail:
        vm_object_drop(efi_obj);
        vm_map_entry_release(count);
        efi_destroy_1t1_map();

        return false;
}

/*
 * Create an environment for the EFI runtime code call.  The most
 * important part is creating the required 1:1 physical->virtual
 * mappings for the runtime segments.  To do that, we manually create
 * page table which unmap userspace but gives correct kernel mapping.
 * The 1:1 mappings for runtime segments usually occupy low 4G of the
 * physical address map.
 *
 * The 1:1 mappings were chosen over the SetVirtualAddressMap() EFI RT
 * service, because there are some BIOSes which fail to correctly
 * relocate itself on the call, requiring both 1:1 and virtual
 * mapping.  As result, we must provide 1:1 mapping anyway, so no
 * reason to bother with the virtual map, and no need to add a
 * complexity into loader.
 *
 * The fpu_kern_enter() call allows firmware to use FPU, as mandated
 * by the specification.  In particular, CR0.TS bit is cleared.  Also
 * it enters critical section, giving us neccessary protection against
 * context switch.
 *
 * There is no need to disable interrupts around the change of %cr3,
 * the kernel mappings are correct, while we only grabbed the
 * userspace portion of VA.  Interrupts handlers must not access
 * userspace.  Having interrupts enabled fixes the issue with
 * firmware/SMM long operation, which would negatively affect IPIs,
 * esp. TLB shootdown requests.
 *
 * We must disable SMAP (aka smap_open()) operation to access the
 * direct map as it will likely be using userspace addresses.
 */
static int
efi_enter(void)
{
        thread_t td = curthread;

        if (efi_runtime == NULL)
                return (ENXIO);
        if (td->td_lwp == NULL)
                return (ENXIO);
        lockmgr(&efi_lock, LK_EXCLUSIVE);
        efi_savevm = td->td_lwp->lwp_vmspace;
        pmap_setlwpvm(td->td_lwp, efi_vmspace);
        npxpush(&efi_ctx);
        cpu_invltlb();
        smap_smep_disable();

        return (0);
}

static void
efi_leave(void)
{
        thread_t td = curthread;

        smap_smep_enable();
        pmap_setlwpvm(td->td_lwp, efi_savevm);
        npxpop(&efi_ctx);
        cpu_invltlb();
        efi_savevm = NULL;
        lockmgr(&efi_lock, LK_RELEASE);
}

static void
efi_shutdown_final(void *arg, int howto)
{
        int error;

        if ((howto & RB_HALT) == 0) {
                error = efi_reset_system();
                if (error)
                        kprintf("EFI Reset failed: %d\n", error);
                DELAY(1000000);
                kprintf("Reset failed - timeout\n");
        }
}

static int
efi_init(void)
{
        struct efi_map_header *efihdr;
        struct efi_md *map;
        caddr_t kmdp;
        size_t efisz;

        lockinit(&efi_lock, "efi", 0, LK_CANRECURSE);
        lockinit(&resettodr_lock, "efitodr", 0, LK_CANRECURSE);

        if (efi_systbl_phys == 0) {
                if (bootverbose)
                        kprintf("EFI systbl not available\n");
                return (ENXIO);
        }
        efi_systbl = (struct efi_systbl *)PHYS_TO_DMAP(efi_systbl_phys);
        if (efi_systbl->st_hdr.th_sig != EFI_SYSTBL_SIG) {
                efi_systbl = NULL;
                if (bootverbose)
                        kprintf("EFI systbl signature invalid\n");
                return (ENXIO);
        }
        efi_cfgtbl = (efi_systbl->st_cfgtbl == 0) ? NULL :
            (struct efi_cfgtbl *)efi_systbl->st_cfgtbl;
        if (efi_cfgtbl == NULL) {
                if (bootverbose)
                        kprintf("EFI config table is not present\n");
        }

        kmdp = preload_search_by_type("elf kernel");
        if (kmdp == NULL)
                kmdp = preload_search_by_type("elf64 kernel");
        efihdr = (struct efi_map_header *)preload_search_info(kmdp,
            MODINFO_METADATA | MODINFOMD_EFI_MAP);
        if (efihdr == NULL) {
                if (bootverbose)
                        kprintf("EFI map is not present\n");
                return (ENXIO);
        }
        efisz = (sizeof(struct efi_map_header) + 0xf) & ~0xf;
        map = (struct efi_md *)((uint8_t *)efihdr + efisz);
        if (efihdr->descriptor_size == 0)
                return (ENOMEM);

        if (!efi_create_1t1_map(map, efihdr->memory_size /
            efihdr->descriptor_size, efihdr->descriptor_size)) {
                if (bootverbose)
                        kprintf("EFI cannot create runtime map\n");
                return (ENOMEM);
        }

        efi_runtime = (efi_systbl->st_rt == 0) ? NULL :
                        (struct efi_rt *)efi_systbl->st_rt;
        if (efi_runtime == NULL) {
                if (bootverbose)
                        kprintf("EFI runtime services table is not present\n");
                efi_destroy_1t1_map();
                return (ENXIO);
        }

        // Lower priority than ACPI Reset
        EVENTHANDLER_REGISTER(shutdown_final, efi_shutdown_final, NULL,
            SHUTDOWN_PRI_LAST+1);

        return (0);
}

static void
efi_uninit(void)
{
        efi_destroy_1t1_map();

        efi_systbl = NULL;
        efi_cfgtbl = NULL;
        efi_runtime = NULL;

        lockuninit(&efi_lock);
        lockuninit(&resettodr_lock);
}

int
efi_get_table(struct uuid *uuid, void **ptr)
{
        struct efi_cfgtbl *ct;
        u_long count;

        if (efi_cfgtbl == NULL)
                return (ENXIO);
        count = efi_systbl->st_entries;
        ct = efi_cfgtbl;
        while (count--) {
                if (!bcmp(&ct->ct_uuid, uuid, sizeof(*uuid))) {
                        *ptr = (void *)PHYS_TO_DMAP(ct->ct_data);
                        return (0);
                }
                ct++;
        }
        return (ENOENT);
}

int
efi_get_time_locked(struct efi_tm *tm)
{
        efi_status status;
        int error;

        KKASSERT(lockowned(&resettodr_lock) != 0);
        error = efi_enter();
        if (error != 0)
                return (error);
        status = efi_runtime->rt_gettime(tm, NULL);
        efi_leave();
        error = efi_status_to_errno(status);

        return (error);
}

int
efi_get_time(struct efi_tm *tm)
{
        int error;

        if (efi_runtime == NULL)
                return (ENXIO);
        lockmgr(&resettodr_lock, LK_EXCLUSIVE);
        error = efi_get_time_locked(tm);
        lockmgr(&resettodr_lock, LK_RELEASE);

        return (error);
}

int
efi_reset_system(void)
{
        int error;

        error = efi_enter();
        if (error != 0)
                return (error);
        efi_runtime->rt_reset(EFI_RESET_WARM, 0, 0, NULL);
        efi_leave();
        return (EIO);
}

int
efi_set_time_locked(struct efi_tm *tm)
{
        efi_status status;
        int error;

        KKASSERT(lockowned(&resettodr_lock) != 0);
        error = efi_enter();
        if (error != 0)
                return (error);
        status = efi_runtime->rt_settime(tm);
        efi_leave();
        error = efi_status_to_errno(status);
        return (error);
}

int
efi_set_time(struct efi_tm *tm)
{
        int error;

        if (efi_runtime == NULL)
                return (ENXIO);
        lockmgr(&resettodr_lock, LK_EXCLUSIVE);
        error = efi_set_time_locked(tm);
        lockmgr(&resettodr_lock, LK_RELEASE);
        return (error);
}

int
efi_var_get(efi_char *name, struct uuid *vendor, uint32_t *attrib,
    size_t *datasize, void *data)
{
        efi_status status;
        int error;

        error = efi_enter();
        if (error != 0)
                return (error);
        status = efi_runtime->rt_getvar(name, vendor, attrib, datasize, data);
        efi_leave();
        error = efi_status_to_errno(status);
        return (error);
}

int
efi_var_nextname(size_t *namesize, efi_char *name, struct uuid *vendor)
{
        efi_status status;
        int error;

        error = efi_enter();
        if (error != 0)
                return (error);
        status = efi_runtime->rt_scanvar(namesize, name, vendor);
        efi_leave();
        error = efi_status_to_errno(status);
        return (error);
}

int
efi_var_set(efi_char *name, struct uuid *vendor, uint32_t attrib,
    size_t datasize, void *data)
{
        efi_status status;
        int error;

        error = efi_enter();
        if (error != 0)
                return (error);
        status = efi_runtime->rt_setvar(name, vendor, attrib, datasize, data);
        efi_leave();
        error = efi_status_to_errno(status);
        return (error);
}

static int
efirt_modevents(module_t m, int event, void *arg __unused)
{

        switch (event) {
        case MOD_LOAD:
                return (efi_init());

        case MOD_UNLOAD:
                efi_uninit();
                return (0);

        case MOD_SHUTDOWN:
                return (0);

        default:
                return (EOPNOTSUPP);
        }
}

static moduledata_t efirt_moddata = {
        .name = "efirt",
        .evhand = efirt_modevents,
        .priv = NULL,
};

DECLARE_MODULE(efirt, efirt_moddata, SI_SUB_DRIVERS, SI_ORDER_ANY);
MODULE_VERSION(efirt, 1);


/* XXX debug stuff */
static int
efi_time_sysctl_handler(SYSCTL_HANDLER_ARGS)
{
        struct efi_tm tm;
        int error, val;

        val = 0;
        error = sysctl_handle_int(oidp, &val, 0, req);
        if (error != 0 || req->newptr == NULL)
                return (error);
        error = efi_get_time(&tm);
        if (error == 0) {
                uprintf("EFI reports: Year %d Month %d Day %d Hour %d Min %d "
                    "Sec %d\n", tm.tm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
                    tm.tm_min, tm.tm_sec);
        }
        return (error);
}

SYSCTL_PROC(_debug, OID_AUTO, efi_time, CTLTYPE_INT | CTLFLAG_RW, NULL, 0,
            efi_time_sysctl_handler, "I", "");