// SPDX-License-Identifier: GPL-2.0
/*
 * 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
 */

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

#include "efistub.h"

#define EFI_DT_ADDR_CELLS_DEFAULT 2
#define EFI_DT_SIZE_CELLS_DEFAULT 2

static void fdt_update_cell_size(void *fdt)
{
        int offset;

        offset = fdt_path_offset(fdt, "/");
        /* Set the #address-cells and #size-cells values for an empty tree */

        fdt_setprop_u32(fdt, offset, "#address-cells", EFI_DT_ADDR_CELLS_DEFAULT);
        fdt_setprop_u32(fdt, offset, "#size-cells",    EFI_DT_SIZE_CELLS_DEFAULT);
}

static efi_status_t update_fdt(void *orig_fdt, unsigned long orig_fdt_size,
                               void *fdt, int new_fdt_size, char *cmdline_ptr)
{
        int node, 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)) {
                        efi_err("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) {
                        efi_err("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) {
                        /*
                         * Any failure from the following function is
                         * non-critical:
                         */
                        fdt_update_cell_size(fdt);
                }
        }

        if (status != 0)
                goto fdt_set_fail;

        /*
         * 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) {
                        /* 'node' is an error code when negative: */
                        status = node;
                        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;
        }

        /* 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)efi_system_table);

        status = fdt_setprop_var(fdt, node, "linux,uefi-system-table", fdt_val64);
        if (status)
                goto fdt_set_fail;

        fdt_val64 = U64_MAX; /* placeholder */

        status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-start", fdt_val64);
        if (status)
                goto fdt_set_fail;

        fdt_val32 = U32_MAX; /* placeholder */

        status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-size", fdt_val32);
        if (status)
                goto fdt_set_fail;

        status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32);
        if (status)
                goto fdt_set_fail;

        status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32);
        if (status)
                goto fdt_set_fail;

        if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && !efi_nokaslr) {
                efi_status_t efi_status;

                efi_status = efi_get_random_bytes(sizeof(fdt_val64),
                                                  (u8 *)&fdt_val64);
                if (efi_status == EFI_SUCCESS) {
                        status = fdt_setprop_var(fdt, node, "kaslr-seed", fdt_val64);
                        if (status)
                                goto fdt_set_fail;
                }
        }

        /* Shrink the FDT back to its minimum size: */
        fdt_pack(fdt);

        return EFI_SUCCESS;

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

        return EFI_LOAD_ERROR;
}

static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map)
{
        int node = fdt_path_offset(fdt, "/chosen");
        u64 fdt_val64;
        u32 fdt_val32;
        int err;

        if (node < 0)
                return EFI_LOAD_ERROR;

        fdt_val64 = cpu_to_fdt64((unsigned long)map->map);

        err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-start", fdt_val64);
        if (err)
                return EFI_LOAD_ERROR;

        fdt_val32 = cpu_to_fdt32(map->map_size);

        err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-size", fdt_val32);
        if (err)
                return EFI_LOAD_ERROR;

        fdt_val32 = cpu_to_fdt32(map->desc_size);

        err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32);
        if (err)
                return EFI_LOAD_ERROR;

        fdt_val32 = cpu_to_fdt32(map->desc_ver);

        err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32);
        if (err)
                return EFI_LOAD_ERROR;

        return EFI_SUCCESS;
}

struct exit_boot_struct {
        struct efi_boot_memmap  *boot_memmap;
        efi_memory_desc_t       *runtime_map;
        int                     runtime_entry_count;
        void                    *new_fdt_addr;
};

static efi_status_t exit_boot_func(struct efi_boot_memmap *map, void *priv)
{
        struct exit_boot_struct *p = priv;

        p->boot_memmap = map;

        /*
         * 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 to SetVirtualAddressMap()
         */
        efi_get_virtmap(map->map, map->map_size, map->desc_size,
                        p->runtime_map, &p->runtime_entry_count);

        return update_fdt_memmap(p->new_fdt_addr, map);
}

#ifndef MAX_FDT_SIZE
# define MAX_FDT_SIZE SZ_2M
#endif

/*
 * Allocate memory for a new FDT, then add EFI and commandline 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.
 */
static
efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
                                            efi_loaded_image_t *image,
                                            unsigned long *new_fdt_addr,
                                            char *cmdline_ptr)
{
        unsigned long desc_size;
        u32 desc_ver;
        efi_status_t status;
        struct exit_boot_struct priv;
        unsigned long fdt_addr = 0;
        unsigned long fdt_size = 0;

        if (!efi_novamap) {
                status = efi_alloc_virtmap(&priv.runtime_map, &desc_size,
                                           &desc_ver);
                if (status != EFI_SUCCESS) {
                        efi_err("Unable to retrieve UEFI memory map.\n");
                        return status;
                }
        }

        /*
         * Unauthenticated device tree data is a security hazard, so ignore
         * 'dtb=' unless UEFI Secure Boot is disabled.  We assume that secure
         * boot is enabled if we can't determine its state.
         */
        if (!IS_ENABLED(CONFIG_EFI_ARMSTUB_DTB_LOADER) ||
            efi_get_secureboot() != efi_secureboot_mode_disabled) {
                if (strstr(cmdline_ptr, "dtb="))
                        efi_err("Ignoring DTB from command line.\n");
        } else {
                status = efi_load_dtb(image, &fdt_addr, &fdt_size);

                if (status != EFI_SUCCESS && status != EFI_NOT_READY) {
                        efi_err("Failed to load device tree!\n");
                        goto fail;
                }
        }

        if (fdt_addr) {
                efi_info("Using DTB from command line\n");
        } else {
                /* Look for a device tree configuration table entry. */
                fdt_addr = (uintptr_t)get_fdt(&fdt_size);
                if (fdt_addr)
                        efi_info("Using DTB from configuration table\n");
        }

        if (!fdt_addr)
                efi_info("Generating empty DTB\n");

        efi_info("Exiting boot services...\n");

        status = efi_allocate_pages(MAX_FDT_SIZE, new_fdt_addr, ULONG_MAX);
        if (status != EFI_SUCCESS) {
                efi_err("Unable to allocate memory for new device tree.\n");
                goto fail;
        }

        status = update_fdt((void *)fdt_addr, fdt_size,
                            (void *)*new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr);

        if (status != EFI_SUCCESS) {
                efi_err("Unable to construct new device tree.\n");
                goto fail_free_new_fdt;
        }

        priv.new_fdt_addr = (void *)*new_fdt_addr;

        status = efi_exit_boot_services(handle, &priv, exit_boot_func);

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

                if (efi_novamap)
                        return EFI_SUCCESS;

                /* Install the new virtual address map */
                svam = efi_system_table->runtime->set_virtual_address_map;
                status = svam(priv.runtime_entry_count * desc_size, desc_size,
                              desc_ver, priv.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) {
                        efi_memory_desc_t *p;
                        int l;

                        /*
                         * Set the virtual address field of all
                         * EFI_MEMORY_RUNTIME entries to U64_MAX. This will
                         * signal the incoming kernel that no virtual
                         * translation has been installed.
                         */
                        for (l = 0; l < priv.boot_memmap->map_size;
                             l += priv.boot_memmap->desc_size) {
                                p = (void *)priv.boot_memmap->map + l;

                                if (p->attribute & EFI_MEMORY_RUNTIME)
                                        p->virt_addr = U64_MAX;
                        }
                }
                return EFI_SUCCESS;
        }

        efi_err("Exit boot services failed.\n");

fail_free_new_fdt:
        efi_free(MAX_FDT_SIZE, *new_fdt_addr);

fail:
        efi_free(fdt_size, fdt_addr);
        if (!efi_novamap)
                efi_bs_call(free_pool, priv.runtime_map);

        return EFI_LOAD_ERROR;
}

efi_status_t efi_boot_kernel(void *handle, efi_loaded_image_t *image,
                             unsigned long kernel_addr, char *cmdline_ptr)
{
        unsigned long fdt_addr;
        efi_status_t status;

        status = allocate_new_fdt_and_exit_boot(handle, image, &fdt_addr,
                                                cmdline_ptr);
        if (status != EFI_SUCCESS) {
                efi_err("Failed to update FDT and exit boot services\n");
                return status;
        }

        if (IS_ENABLED(CONFIG_ARM))
                efi_handle_post_ebs_state();

        efi_enter_kernel(kernel_addr, fdt_addr, fdt_totalsize((void *)fdt_addr));
        /* not reached */
}

void *get_fdt(unsigned long *fdt_size)
{
        void *fdt;

        fdt = get_efi_config_table(DEVICE_TREE_GUID);

        if (!fdt)
                return NULL;

        if (fdt_check_header(fdt) != 0) {
                efi_err("Invalid header detected on UEFI supplied FDT, ignoring ...\n");
                return NULL;
        }
        *fdt_size = fdt_totalsize(fdt);
        return fdt;
}