/*
 * FDT related Helper functions used by the EFI stub on multiple
 * architectures. This should be #included by the EFI stub
 * implementation files.
 *
 * Copyright 2013 Linaro Limited; author Roy Franz
 *
 * This file is part of the Linux kernel, and is made available
 * under the terms of the GNU General Public License version 2.
 *
 */

#include <linux/efi.h>
#include <linux/libfdt.h>
#include <asm/efi.h>

#include "efistub.h"

efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
                        unsigned long orig_fdt_size,
                        void *fdt, int new_fdt_size, char *cmdline_ptr,
                        u64 initrd_addr, u64 initrd_size,
                        efi_memory_desc_t *memory_map,
                        unsigned long map_size, unsigned long desc_size,
                        u32 desc_ver)
{
        int node, prev, num_rsv;
        int status;
        u32 fdt_val32;
        u64 fdt_val64;

        /* Do some checks on provided FDT, if it exists*/
        if (orig_fdt) {
                if (fdt_check_header(orig_fdt)) {
                        pr_efi_err(sys_table, "Device Tree header not valid!\n");
                        return EFI_LOAD_ERROR;
                }
                /*
                 * We don't get the size of the FDT if we get if from a
                 * configuration table.
                 */
                if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) {
                        pr_efi_err(sys_table, "Truncated device tree! foo!\n");
                        return EFI_LOAD_ERROR;
                }
        }

        if (orig_fdt)
                status = fdt_open_into(orig_fdt, fdt, new_fdt_size);
        else
                status = fdt_create_empty_tree(fdt, new_fdt_size);

        if (status != 0)
                goto fdt_set_fail;

        /*
         * Delete any memory nodes present. We must delete nodes which
         * early_init_dt_scan_memory may try to use.
         */
        prev = 0;
        for (;;) {
                const char *type;
                int len;

                node = fdt_next_node(fdt, prev, NULL);
                if (node < 0)
                        break;

                type = fdt_getprop(fdt, node, "device_type", &len);
                if (type && strncmp(type, "memory", len) == 0) {
                        fdt_del_node(fdt, node);
                        continue;
                }

                prev = node;
        }

        /*
         * Delete all memory reserve map entries. When booting via UEFI,
         * kernel will use the UEFI memory map to find reserved regions.
         */
        num_rsv = fdt_num_mem_rsv(fdt);
        while (num_rsv-- > 0)
                fdt_del_mem_rsv(fdt, num_rsv);

        node = fdt_subnode_offset(fdt, 0, "chosen");
        if (node < 0) {
                node = fdt_add_subnode(fdt, 0, "chosen");
                if (node < 0) {
                        status = node; /* node is error code when negative */
                        goto fdt_set_fail;
                }
        }

        if ((cmdline_ptr != NULL) && (strlen(cmdline_ptr) > 0)) {
                status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr,
                                     strlen(cmdline_ptr) + 1);
                if (status)
                        goto fdt_set_fail;
        }

        /* Set initrd address/end in device tree, if present */
        if (initrd_size != 0) {
                u64 initrd_image_end;
                u64 initrd_image_start = cpu_to_fdt64(initrd_addr);

                status = fdt_setprop(fdt, node, "linux,initrd-start",
                                     &initrd_image_start, sizeof(u64));
                if (status)
                        goto fdt_set_fail;
                initrd_image_end = cpu_to_fdt64(initrd_addr + initrd_size);
                status = fdt_setprop(fdt, node, "linux,initrd-end",
                                     &initrd_image_end, sizeof(u64));
                if (status)
                        goto fdt_set_fail;
        }

        /* Add FDT entries for EFI runtime services in chosen node. */
        node = fdt_subnode_offset(fdt, 0, "chosen");
        fdt_val64 = cpu_to_fdt64((u64)(unsigned long)sys_table);
        status = fdt_setprop(fdt, node, "linux,uefi-system-table",
                             &fdt_val64, sizeof(fdt_val64));
        if (status)
                goto fdt_set_fail;

        fdt_val64 = cpu_to_fdt64((u64)(unsigned long)memory_map);
        status = fdt_setprop(fdt, node, "linux,uefi-mmap-start",
                             &fdt_val64,  sizeof(fdt_val64));
        if (status)
                goto fdt_set_fail;

        fdt_val32 = cpu_to_fdt32(map_size);
        status = fdt_setprop(fdt, node, "linux,uefi-mmap-size",
                             &fdt_val32,  sizeof(fdt_val32));
        if (status)
                goto fdt_set_fail;

        fdt_val32 = cpu_to_fdt32(desc_size);
        status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-size",
                             &fdt_val32, sizeof(fdt_val32));
        if (status)
                goto fdt_set_fail;

        fdt_val32 = cpu_to_fdt32(desc_ver);
        status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-ver",
                             &fdt_val32, sizeof(fdt_val32));
        if (status)
                goto fdt_set_fail;

        if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
                efi_status_t efi_status;

                efi_status = efi_get_random_bytes(sys_table, sizeof(fdt_val64),
                                                  (u8 *)&fdt_val64);
                if (efi_status == EFI_SUCCESS) {
                        status = fdt_setprop(fdt, node, "kaslr-seed",
                                             &fdt_val64, sizeof(fdt_val64));
                        if (status)
                                goto fdt_set_fail;
                } else if (efi_status != EFI_NOT_FOUND) {
                        return efi_status;
                }
        }
        return EFI_SUCCESS;

fdt_set_fail:
        if (status == -FDT_ERR_NOSPACE)
                return EFI_BUFFER_TOO_SMALL;

        return EFI_LOAD_ERROR;
}

#ifndef EFI_FDT_ALIGN
#define EFI_FDT_ALIGN EFI_PAGE_SIZE
#endif

/*
 * Allocate memory for a new FDT, then add EFI, commandline, and
 * initrd related fields to the FDT.  This routine increases the
 * FDT allocation size until the allocated memory is large
 * enough.  EFI allocations are in EFI_PAGE_SIZE granules,
 * which are fixed at 4K bytes, so in most cases the first
 * allocation should succeed.
 * EFI boot services are exited at the end of this function.
 * There must be no allocations between the get_memory_map()
 * call and the exit_boot_services() call, so the exiting of
 * boot services is very tightly tied to the creation of the FDT
 * with the final memory map in it.
 */

efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
                                            void *handle,
                                            unsigned long *new_fdt_addr,
                                            unsigned long max_addr,
                                            u64 initrd_addr, u64 initrd_size,
                                            char *cmdline_ptr,
                                            unsigned long fdt_addr,
                                            unsigned long fdt_size)
{
        unsigned long map_size, desc_size;
        u32 desc_ver;
        unsigned long mmap_key;
        efi_memory_desc_t *memory_map, *runtime_map;
        unsigned long new_fdt_size;
        efi_status_t status;
        int runtime_entry_count = 0;

        /*
         * Get a copy of the current memory map that we will use to prepare
         * the input for SetVirtualAddressMap(). We don't have to worry about
         * subsequent allocations adding entries, since they could not affect
         * the number of EFI_MEMORY_RUNTIME regions.
         */
        status = efi_get_memory_map(sys_table, &runtime_map, &map_size,
                                    &desc_size, &desc_ver, &mmap_key);
        if (status != EFI_SUCCESS) {
                pr_efi_err(sys_table, "Unable to retrieve UEFI memory map.\n");
                return status;
        }

        pr_efi(sys_table,
               "Exiting boot services and installing virtual address map...\n");

        /*
         * Estimate size of new FDT, and allocate memory for it. We
         * will allocate a bigger buffer if this ends up being too
         * small, so a rough guess is OK here.
         */
        new_fdt_size = fdt_size + EFI_PAGE_SIZE;
        while (1) {
                status = efi_high_alloc(sys_table, new_fdt_size, EFI_FDT_ALIGN,
                                        new_fdt_addr, max_addr);
                if (status != EFI_SUCCESS) {
                        pr_efi_err(sys_table, "Unable to allocate memory for new device tree.\n");
                        goto fail;
                }

                /*
                 * Now that we have done our final memory allocation (and free)
                 * we can get the memory map key  needed for
                 * exit_boot_services().
                 */
                status = efi_get_memory_map(sys_table, &memory_map, &map_size,
                                            &desc_size, &desc_ver, &mmap_key);
                if (status != EFI_SUCCESS)
                        goto fail_free_new_fdt;

                status = update_fdt(sys_table,
                                    (void *)fdt_addr, fdt_size,
                                    (void *)*new_fdt_addr, new_fdt_size,
                                    cmdline_ptr, initrd_addr, initrd_size,
                                    memory_map, map_size, desc_size, desc_ver);

                /* Succeeding the first time is the expected case. */
                if (status == EFI_SUCCESS)
                        break;

                if (status == EFI_BUFFER_TOO_SMALL) {
                        /*
                         * We need to allocate more space for the new
                         * device tree, so free existing buffer that is
                         * too small.  Also free memory map, as we will need
                         * to get new one that reflects the free/alloc we do
                         * on the device tree buffer.
                         */
                        efi_free(sys_table, new_fdt_size, *new_fdt_addr);
                        sys_table->boottime->free_pool(memory_map);
                        new_fdt_size += EFI_PAGE_SIZE;
                } else {
                        pr_efi_err(sys_table, "Unable to construct new device tree.\n");
                        goto fail_free_mmap;
                }
        }

        /*
         * Update the memory map with virtual addresses. The function will also
         * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME
         * entries so that we can pass it straight into SetVirtualAddressMap()
         */
        efi_get_virtmap(memory_map, map_size, desc_size, runtime_map,
                        &runtime_entry_count);

        /* Now we are ready to exit_boot_services.*/
        status = sys_table->boottime->exit_boot_services(handle, mmap_key);

        if (status == EFI_SUCCESS) {
                efi_set_virtual_address_map_t *svam;

                /* Install the new virtual address map */
                svam = sys_table->runtime->set_virtual_address_map;
                status = svam(runtime_entry_count * desc_size, desc_size,
                              desc_ver, runtime_map);

                /*
                 * We are beyond the point of no return here, so if the call to
                 * SetVirtualAddressMap() failed, we need to signal that to the
                 * incoming kernel but proceed normally otherwise.
                 */
                if (status != EFI_SUCCESS) {
                        int l;

                        /*
                         * Set the virtual address field of all
                         * EFI_MEMORY_RUNTIME entries to 0. This will signal
                         * the incoming kernel that no virtual translation has
                         * been installed.
                         */
                        for (l = 0; l < map_size; l += desc_size) {
                                efi_memory_desc_t *p = (void *)memory_map + l;

                                if (p->attribute & EFI_MEMORY_RUNTIME)
                                        p->virt_addr = 0;
                        }
                }
                return EFI_SUCCESS;
        }

        pr_efi_err(sys_table, "Exit boot services failed.\n");

fail_free_mmap:
        sys_table->boottime->free_pool(memory_map);

fail_free_new_fdt:
        efi_free(sys_table, new_fdt_size, *new_fdt_addr);

fail:
        sys_table->boottime->free_pool(runtime_map);
        return EFI_LOAD_ERROR;
}

void *get_fdt(efi_system_table_t *sys_table, unsigned long *fdt_size)
{
        efi_guid_t fdt_guid = DEVICE_TREE_GUID;
        efi_config_table_t *tables;
        void *fdt;
        int i;

        tables = (efi_config_table_t *) sys_table->tables;
        fdt = NULL;

        for (i = 0; i < sys_table->nr_tables; i++)
                if (efi_guidcmp(tables[i].guid, fdt_guid) == 0) {
                        fdt = (void *) tables[i].table;
                        if (fdt_check_header(fdt) != 0) {
                                pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n");
                                return NULL;
                        }
                        *fdt_size = fdt_totalsize(fdt);
                        break;
         }

        return fdt;
}