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

/* -----------------------------------------------------------------------
 *
 *   Copyright 2011 Intel Corporation; author Matt Fleming
 *
 * ----------------------------------------------------------------------- */

#include <linux/efi.h>
#include <linux/pci.h>
#include <linux/stddef.h>

#include <asm/efi.h>
#include <asm/e820/types.h>
#include <asm/setup.h>
#include <asm/desc.h>
#include <asm/boot.h>
#include <asm/kaslr.h>
#include <asm/sev.h>

#include "efistub.h"
#include "x86-stub.h"

extern char _bss[], _ebss[];

const efi_system_table_t *efi_system_table;
const efi_dxe_services_table_t *efi_dxe_table;
static efi_loaded_image_t *image = NULL;
static efi_memory_attribute_protocol_t *memattr;

typedef union sev_memory_acceptance_protocol sev_memory_acceptance_protocol_t;
union sev_memory_acceptance_protocol {
        struct {
                efi_status_t (__efiapi * allow_unaccepted_memory)(
                        sev_memory_acceptance_protocol_t *);
        };
        struct {
                u32 allow_unaccepted_memory;
        } mixed_mode;
};

static efi_status_t
preserve_pci_rom_image(efi_pci_io_protocol_t *pci, struct pci_setup_rom **__rom)
{
        struct pci_setup_rom *rom __free(efi_pool) = NULL;
        efi_status_t status;
        unsigned long size;
        uint64_t romsize;
        void *romimage;

        /*
         * Some firmware images contain EFI function pointers at the place where
         * the romimage and romsize fields are supposed to be. Typically the EFI
         * code is mapped at high addresses, translating to an unrealistically
         * large romsize. The UEFI spec limits the size of option ROMs to 16
         * MiB so we reject any ROMs over 16 MiB in size to catch this.
         */
        romimage = efi_table_attr(pci, romimage);
        romsize = efi_table_attr(pci, romsize);
        if (!romimage || !romsize || romsize > SZ_16M)
                return EFI_INVALID_PARAMETER;

        size = romsize + sizeof(*rom);

        status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
                             (void **)&rom);
        if (status != EFI_SUCCESS) {
                efi_err("Failed to allocate memory for 'rom'\n");
                return status;
        }

        memset(rom, 0, sizeof(*rom));

        rom->data.type  = SETUP_PCI;
        rom->data.len   = size - sizeof(struct setup_data);
        rom->data.next  = 0;
        rom->pcilen     = romsize;

        status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
                                PCI_VENDOR_ID, 1, &rom->vendor);

        if (status != EFI_SUCCESS) {
                efi_err("Failed to read rom->vendor\n");
                return status;
        }

        status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16,
                                PCI_DEVICE_ID, 1, &rom->devid);

        if (status != EFI_SUCCESS) {
                efi_err("Failed to read rom->devid\n");
                return status;
        }

        status = efi_call_proto(pci, get_location, &rom->segment, &rom->bus,
                                &rom->device, &rom->function);

        if (status != EFI_SUCCESS)
                return status;

        memcpy(rom->romdata, romimage, romsize);
        *__rom = no_free_ptr(rom);
        return EFI_SUCCESS;
}

/*
 * There's no way to return an informative status from this function,
 * because any analysis (and printing of error messages) needs to be
 * done directly at the EFI function call-site.
 *
 * For example, EFI_INVALID_PARAMETER could indicate a bug or maybe we
 * just didn't find any PCI devices, but there's no way to tell outside
 * the context of the call.
 */
static void setup_efi_pci(struct boot_params *params)
{
        efi_status_t status;
        efi_handle_t *pci_handle __free(efi_pool) = NULL;
        efi_guid_t pci_proto = EFI_PCI_IO_PROTOCOL_GUID;
        struct setup_data *data;
        unsigned long num;
        efi_handle_t h;

        status = efi_bs_call(locate_handle_buffer, EFI_LOCATE_BY_PROTOCOL,
                             &pci_proto, NULL, &num, &pci_handle);
        if (status != EFI_SUCCESS)
                return;

        data = (struct setup_data *)(unsigned long)params->hdr.setup_data;

        while (data && data->next)
                data = (struct setup_data *)(unsigned long)data->next;

        for_each_efi_handle(h, pci_handle, num) {
                efi_pci_io_protocol_t *pci = NULL;
                struct pci_setup_rom *rom;

                status = efi_bs_call(handle_protocol, h, &pci_proto,
                                     (void **)&pci);
                if (status != EFI_SUCCESS || !pci)
                        continue;

                status = preserve_pci_rom_image(pci, &rom);
                if (status != EFI_SUCCESS)
                        continue;

                if (data)
                        data->next = (unsigned long)rom;
                else
                        params->hdr.setup_data = (unsigned long)rom;

                data = (struct setup_data *)rom;
        }
}

static void retrieve_apple_device_properties(struct boot_params *boot_params)
{
        efi_guid_t guid = APPLE_PROPERTIES_PROTOCOL_GUID;
        struct setup_data *data, *new;
        efi_status_t status;
        u32 size = 0;
        apple_properties_protocol_t *p;

        status = efi_bs_call(locate_protocol, &guid, NULL, (void **)&p);
        if (status != EFI_SUCCESS)
                return;

        if (efi_table_attr(p, version) != 0x10000) {
                efi_err("Unsupported properties proto version\n");
                return;
        }

        efi_call_proto(p, get_all, NULL, &size);
        if (!size)
                return;

        do {
                status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,
                                     size + sizeof(struct setup_data),
                                     (void **)&new);
                if (status != EFI_SUCCESS) {
                        efi_err("Failed to allocate memory for 'properties'\n");
                        return;
                }

                status = efi_call_proto(p, get_all, new->data, &size);

                if (status == EFI_BUFFER_TOO_SMALL)
                        efi_bs_call(free_pool, new);
        } while (status == EFI_BUFFER_TOO_SMALL);

        new->type = SETUP_APPLE_PROPERTIES;
        new->len  = size;
        new->next = 0;

        data = (struct setup_data *)(unsigned long)boot_params->hdr.setup_data;
        if (!data) {
                boot_params->hdr.setup_data = (unsigned long)new;
        } else {
                while (data->next)
                        data = (struct setup_data *)(unsigned long)data->next;
                data->next = (unsigned long)new;
        }
}

struct smbios_entry_point {
        u8      anchor[4];
        u8      ep_checksum;
        u8      ep_length;
        u8      major_version;
        u8      minor_version;
        u16     max_size_entry;
        u8      ep_rev;
        u8      reserved[5];

        struct __packed {
                u8      anchor[5];
                u8      checksum;
                u16     st_length;
                u32     st_address;
                u16     number_of_entries;
                u8      bcd_rev;
        } intm;
};

static bool verify_ep_checksum(const void *ptr, int length)
{
        u8 sum = 0;

        for (int i = 0; i < length; i++)
                sum += ((u8 *)ptr)[i];

        return sum == 0;
}

static bool verify_ep_integrity(const struct smbios_entry_point *ep)
{
        if (memcmp(ep->anchor, "_SM_", sizeof(ep->anchor)) != 0)
                return false;

        if (memcmp(ep->intm.anchor, "_DMI_", sizeof(ep->intm.anchor)) != 0)
                return false;

        if (!verify_ep_checksum(ep, ep->ep_length) ||
            !verify_ep_checksum(&ep->intm, sizeof(ep->intm)))
                return false;

        return true;
}

static const struct efi_smbios_record *search_record(void *table, u32 length,
                                                     u8 type)
{
        const u8 *p, *end;

        p = (u8 *)table;
        end = p + length;

        while (p + sizeof(struct efi_smbios_record) < end) {
                const struct efi_smbios_record *hdr =
                        (struct efi_smbios_record *)p;
                const u8 *next;

                if (hdr->type == type)
                        return hdr;

                /* Type 127 = End-of-Table */
                if (hdr->type == 0x7F)
                        return NULL;

                /* Jumping to the unformed section */
                next = p + hdr->length;

                /* Unformed section ends with 0000h */
                while ((next[0] != 0 || next[1] != 0) && next + 1 < end)
                        next++;

                next += 2;
                p = next;
        }

        return NULL;
}

static const struct efi_smbios_record *get_table_record(u8 type)
{
        const struct smbios_entry_point *ep;

        /*
         * Locate the legacy 32-bit SMBIOS entrypoint in memory, and parse it
         * directly. Needed by some Macs that do not implement the EFI protocol.
         */
        ep = get_efi_config_table(SMBIOS_TABLE_GUID);
        if (!ep)
                return NULL;

        if (!verify_ep_integrity(ep))
                return NULL;

        return search_record((void *)(unsigned long)ep->intm.st_address,
                             ep->intm.st_length, type);
}

static bool apple_match_product_name(void)
{
        static const char type1_product_matches[][15] = {
                "MacBookPro11,3",
                "MacBookPro11,5",
                "MacBookPro13,3",
                "MacBookPro14,3",
                "MacBookPro15,1",
                "MacBookPro15,3",
                "MacBookPro16,1",
                "MacBookPro16,4",
        };
        const struct efi_smbios_type1_record *record;
        const u8 *product;

        record = (struct efi_smbios_type1_record *)
                        (efi_get_smbios_record(1) ?: get_table_record(1));
        if (!record)
                return false;

        product = efi_get_smbios_string(record, product_name);
        if (!product)
                return false;

        for (int i = 0; i < ARRAY_SIZE(type1_product_matches); i++) {
                if (!strcmp(product, type1_product_matches[i]))
                        return true;
        }

        return false;
}

static void apple_set_os(void)
{
        struct {
                unsigned long version;
                efi_status_t (__efiapi *set_os_version)(const char *);
                efi_status_t (__efiapi *set_os_vendor)(const char *);
        } *set_os;
        efi_status_t status;

        if (!efi_is_64bit() || !apple_match_product_name())
                return;

        status = efi_bs_call(locate_protocol, &APPLE_SET_OS_PROTOCOL_GUID, NULL,
                             (void **)&set_os);
        if (status != EFI_SUCCESS)
                return;

        if (set_os->version >= 2) {
                status = set_os->set_os_vendor("Apple Inc.");
                if (status != EFI_SUCCESS)
                        efi_err("Failed to set OS vendor via apple_set_os\n");
        }

        if (set_os->version > 0) {
                /* The version being set doesn't seem to matter */
                status = set_os->set_os_version("Mac OS X 10.9");
                if (status != EFI_SUCCESS)
                        efi_err("Failed to set OS version via apple_set_os\n");
        }
}

efi_status_t efi_adjust_memory_range_protection(unsigned long start,
                                                unsigned long size)
{
        efi_status_t status;
        efi_gcd_memory_space_desc_t desc;
        unsigned long end, next;
        unsigned long rounded_start, rounded_end;
        unsigned long unprotect_start, unprotect_size;

        rounded_start = rounddown(start, EFI_PAGE_SIZE);
        rounded_end = roundup(start + size, EFI_PAGE_SIZE);

        if (memattr != NULL) {
                status = efi_call_proto(memattr, set_memory_attributes,
                                        rounded_start,
                                        rounded_end - rounded_start,
                                        EFI_MEMORY_RO);
                if (status != EFI_SUCCESS) {
                        efi_warn("Failed to set EFI_MEMORY_RO attribute\n");
                        return status;
                }

                status = efi_call_proto(memattr, clear_memory_attributes,
                                        rounded_start,
                                        rounded_end - rounded_start,
                                        EFI_MEMORY_XP);
                if (status != EFI_SUCCESS)
                        efi_warn("Failed to clear EFI_MEMORY_XP attribute\n");
                return status;
        }

        if (efi_dxe_table == NULL)
                return EFI_SUCCESS;

        /*
         * Don't modify memory region attributes, if they are
         * already suitable, to lower the possibility to
         * encounter firmware bugs.
         */

        for (end = start + size; start < end; start = next) {

                status = efi_dxe_call(get_memory_space_descriptor, start, &desc);

                if (status != EFI_SUCCESS)
                        break;

                next = desc.base_address + desc.length;

                /*
                 * Only system memory and more reliable memory are suitable for
                 * trampoline/kernel image placement. So only those memory types
                 * may need to have attributes modified.
                 */

                if ((desc.gcd_memory_type != EfiGcdMemoryTypeSystemMemory &&
                     desc.gcd_memory_type != EfiGcdMemoryTypeMoreReliable) ||
                    (desc.attributes & (EFI_MEMORY_RO | EFI_MEMORY_XP)) == 0)
                        continue;

                unprotect_start = max(rounded_start, (unsigned long)desc.base_address);
                unprotect_size = min(rounded_end, next) - unprotect_start;

                status = efi_dxe_call(set_memory_space_attributes,
                                      unprotect_start, unprotect_size,
                                      EFI_MEMORY_WB);

                if (status != EFI_SUCCESS) {
                        efi_warn("Unable to unprotect memory range [%08lx,%08lx]: %lx\n",
                                 unprotect_start,
                                 unprotect_start + unprotect_size,
                                 status);
                        break;
                }
        }
        return EFI_SUCCESS;
}

static void setup_unaccepted_memory(void)
{
        efi_guid_t mem_acceptance_proto = OVMF_SEV_MEMORY_ACCEPTANCE_PROTOCOL_GUID;
        sev_memory_acceptance_protocol_t *proto;
        efi_status_t status;

        if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY))
                return;

        /*
         * Enable unaccepted memory before calling exit boot services in order
         * for the UEFI to not accept all memory on EBS.
         */
        status = efi_bs_call(locate_protocol, &mem_acceptance_proto, NULL,
                             (void **)&proto);
        if (status != EFI_SUCCESS)
                return;

        status = efi_call_proto(proto, allow_unaccepted_memory);
        if (status != EFI_SUCCESS)
                efi_err("Memory acceptance protocol failed\n");
}

static efi_char16_t *efistub_fw_vendor(void)
{
        unsigned long vendor = efi_table_attr(efi_system_table, fw_vendor);

        return (efi_char16_t *)vendor;
}

static const efi_char16_t apple[] = L"Apple";

static void setup_quirks(struct boot_params *boot_params)
{
        if (!memcmp(efistub_fw_vendor(), apple, sizeof(apple))) {
                if (IS_ENABLED(CONFIG_APPLE_PROPERTIES))
                        retrieve_apple_device_properties(boot_params);

                apple_set_os();
        }
}

static void setup_graphics(struct boot_params *boot_params)
{
        struct screen_info *si = memset(&boot_params->screen_info, 0, sizeof(*si));
        struct edid_info *edid = memset(&boot_params->edid_info, 0, sizeof(*edid));

        efi_setup_graphics(si, edid);
}

static void __noreturn efi_exit(efi_handle_t handle, efi_status_t status)
{
        efi_bs_call(exit, handle, status, 0, NULL);
        for(;;)
                asm("hlt");
}

/*
 * Because the x86 boot code expects to be passed a boot_params we
 * need to create one ourselves (usually the bootloader would create
 * one for us).
 */
static efi_status_t efi_allocate_bootparams(efi_handle_t handle,
                                            struct boot_params **bp)
{
        efi_guid_t proto = LOADED_IMAGE_PROTOCOL_GUID;
        struct boot_params *boot_params;
        struct setup_header *hdr;
        efi_status_t status;
        unsigned long alloc;
        char *cmdline_ptr;

        status = efi_bs_call(handle_protocol, handle, &proto, (void **)&image);
        if (status != EFI_SUCCESS) {
                efi_err("Failed to get handle for LOADED_IMAGE_PROTOCOL\n");
                return status;
        }

        status = efi_allocate_pages(PARAM_SIZE, &alloc, ULONG_MAX);
        if (status != EFI_SUCCESS)
                return status;

        boot_params = memset((void *)alloc, 0x0, PARAM_SIZE);
        hdr         = &boot_params->hdr;

        /* Assign the setup_header fields that the kernel actually cares about */
        hdr->root_flags = 1;
        hdr->vid_mode   = 0xffff;

        hdr->type_of_loader = 0x21;
        hdr->initrd_addr_max = INT_MAX;

        /* Convert unicode cmdline to ascii */
        cmdline_ptr = efi_convert_cmdline(image);
        if (!cmdline_ptr) {
                efi_free(PARAM_SIZE, alloc);
                return EFI_OUT_OF_RESOURCES;
        }

        efi_set_u64_split((unsigned long)cmdline_ptr, &hdr->cmd_line_ptr,
                          &boot_params->ext_cmd_line_ptr);

        *bp = boot_params;
        return EFI_SUCCESS;
}

static void add_e820ext(struct boot_params *params,
                        struct setup_data *e820ext, u32 nr_entries)
{
        struct setup_data *data;

        e820ext->type = SETUP_E820_EXT;
        e820ext->len  = nr_entries * sizeof(struct boot_e820_entry);
        e820ext->next = 0;

        data = (struct setup_data *)(unsigned long)params->hdr.setup_data;

        while (data && data->next)
                data = (struct setup_data *)(unsigned long)data->next;

        if (data)
                data->next = (unsigned long)e820ext;
        else
                params->hdr.setup_data = (unsigned long)e820ext;
}

static efi_status_t
setup_e820(struct boot_params *params, struct setup_data *e820ext, u32 e820ext_size)
{
        struct boot_e820_entry *entry = params->e820_table;
        struct efi_info *efi = &params->efi_info;
        struct boot_e820_entry *prev = NULL;
        u32 nr_entries;
        u32 nr_desc;
        int i;

        nr_entries = 0;
        nr_desc = efi->efi_memmap_size / efi->efi_memdesc_size;

        for (i = 0; i < nr_desc; i++) {
                efi_memory_desc_t *d;
                unsigned int e820_type = 0;
                unsigned long m = efi->efi_memmap;

#ifdef CONFIG_X86_64
                m |= (u64)efi->efi_memmap_hi << 32;
#endif

                d = efi_memdesc_ptr(m, efi->efi_memdesc_size, i);
                switch (d->type) {
                case EFI_RESERVED_TYPE:
                case EFI_RUNTIME_SERVICES_CODE:
                case EFI_RUNTIME_SERVICES_DATA:
                case EFI_MEMORY_MAPPED_IO:
                case EFI_MEMORY_MAPPED_IO_PORT_SPACE:
                case EFI_PAL_CODE:
                        e820_type = E820_TYPE_RESERVED;
                        break;

                case EFI_UNUSABLE_MEMORY:
                        e820_type = E820_TYPE_UNUSABLE;
                        break;

                case EFI_ACPI_RECLAIM_MEMORY:
                        e820_type = E820_TYPE_ACPI;
                        break;

                case EFI_LOADER_CODE:
                case EFI_LOADER_DATA:
                case EFI_BOOT_SERVICES_CODE:
                case EFI_BOOT_SERVICES_DATA:
                case EFI_CONVENTIONAL_MEMORY:
                        if (efi_soft_reserve_enabled() &&
                            (d->attribute & EFI_MEMORY_SP))
                                e820_type = E820_TYPE_SOFT_RESERVED;
                        else
                                e820_type = E820_TYPE_RAM;
                        break;

                case EFI_ACPI_MEMORY_NVS:
                        e820_type = E820_TYPE_NVS;
                        break;

                case EFI_PERSISTENT_MEMORY:
                        e820_type = E820_TYPE_PMEM;
                        break;

                case EFI_UNACCEPTED_MEMORY:
                        if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY))
                                continue;
                        e820_type = E820_TYPE_RAM;
                        process_unaccepted_memory(d->phys_addr,
                                                  d->phys_addr + PAGE_SIZE * d->num_pages);
                        break;
                default:
                        continue;
                }

                /* Merge adjacent mappings */
                if (prev && prev->type == e820_type &&
                    (prev->addr + prev->size) == d->phys_addr) {
                        prev->size += d->num_pages << 12;
                        continue;
                }

                if (nr_entries == ARRAY_SIZE(params->e820_table)) {
                        u32 need = (nr_desc - i) * sizeof(struct e820_entry) +
                                   sizeof(struct setup_data);

                        if (!e820ext || e820ext_size < need)
                                return EFI_BUFFER_TOO_SMALL;

                        /* boot_params map full, switch to e820 extended */
                        entry = (struct boot_e820_entry *)e820ext->data;
                }

                entry->addr = d->phys_addr;
                entry->size = d->num_pages << PAGE_SHIFT;
                entry->type = e820_type;
                prev = entry++;
                nr_entries++;
        }

        if (nr_entries > ARRAY_SIZE(params->e820_table)) {
                u32 nr_e820ext = nr_entries - ARRAY_SIZE(params->e820_table);

                add_e820ext(params, e820ext, nr_e820ext);
                nr_entries -= nr_e820ext;
        }

        params->e820_entries = (u8)nr_entries;

        return EFI_SUCCESS;
}

static efi_status_t alloc_e820ext(u32 nr_desc, struct setup_data **e820ext,
                                  u32 *e820ext_size)
{
        efi_status_t status;
        unsigned long size;

        size = sizeof(struct setup_data) +
                sizeof(struct e820_entry) * nr_desc;

        if (*e820ext) {
                efi_bs_call(free_pool, *e820ext);
                *e820ext = NULL;
                *e820ext_size = 0;
        }

        status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
                             (void **)e820ext);
        if (status == EFI_SUCCESS)
                *e820ext_size = size;

        return status;
}

static efi_status_t allocate_e820(struct boot_params *params,
                                  struct setup_data **e820ext,
                                  u32 *e820ext_size)
{
        struct efi_boot_memmap *map __free(efi_pool) = NULL;
        efi_status_t status;
        __u32 nr_desc;

        status = efi_get_memory_map(&map, false);
        if (status != EFI_SUCCESS)
                return status;

        nr_desc = map->map_size / map->desc_size;
        if (nr_desc > ARRAY_SIZE(params->e820_table) - EFI_MMAP_NR_SLACK_SLOTS) {
                u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table) +
                                 EFI_MMAP_NR_SLACK_SLOTS;

                status = alloc_e820ext(nr_e820ext, e820ext, e820ext_size);
                if (status != EFI_SUCCESS)
                        return status;
        }

        if (IS_ENABLED(CONFIG_UNACCEPTED_MEMORY))
                return allocate_unaccepted_bitmap(nr_desc, map);

        return EFI_SUCCESS;
}

struct exit_boot_struct {
        struct boot_params      *boot_params;
        struct efi_info         *efi;
};

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

        signature = efi_is_64bit() ? EFI64_LOADER_SIGNATURE
                                   : EFI32_LOADER_SIGNATURE;
        memcpy(&p->efi->efi_loader_signature, signature, sizeof(__u32));

        efi_set_u64_split((unsigned long)efi_system_table,
                          &p->efi->efi_systab, &p->efi->efi_systab_hi);
        p->efi->efi_memdesc_size        = map->desc_size;
        p->efi->efi_memdesc_version     = map->desc_ver;
        efi_set_u64_split((unsigned long)map->map,
                          &p->efi->efi_memmap, &p->efi->efi_memmap_hi);
        p->efi->efi_memmap_size         = map->map_size;

        return EFI_SUCCESS;
}

static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
{
        struct setup_data *e820ext = NULL;
        __u32 e820ext_size = 0;
        efi_status_t status;
        struct exit_boot_struct priv;

        priv.boot_params        = boot_params;
        priv.efi                = &boot_params->efi_info;

        status = allocate_e820(boot_params, &e820ext, &e820ext_size);
        if (status != EFI_SUCCESS)
                return status;

        /* Might as well exit boot services now */
        status = efi_exit_boot_services(handle, &priv, exit_boot_func);
        if (status != EFI_SUCCESS)
                return status;

        /* Historic? */
        boot_params->alt_mem_k  = 32 * 1024;

        status = setup_e820(boot_params, e820ext, e820ext_size);
        if (status != EFI_SUCCESS)
                return status;

        return EFI_SUCCESS;
}

static bool have_unsupported_snp_features(void)
{
        u64 unsupported;

        unsupported = snp_get_unsupported_features(sev_get_status());
        if (unsupported) {
                efi_err("Unsupported SEV-SNP features detected: 0x%llx\n",
                        unsupported);
                return true;
        }
        return false;
}

static void efi_get_seed(void *seed, int size)
{
        efi_get_random_bytes(size, seed);

        /*
         * This only updates seed[0] when running on 32-bit, but in that case,
         * seed[1] is not used anyway, as there is no virtual KASLR on 32-bit.
         */
        *(unsigned long *)seed ^= kaslr_get_random_long("EFI");
}

static void error(char *str)
{
        efi_warn("Decompression failed: %s\n", str);
}

static const char *cmdline_memmap_override;

static efi_status_t parse_options(const char *cmdline)
{
        static const char opts[][14] = {
                "mem=", "memmap=", "hugepages="
        };

        for (int i = 0; i < ARRAY_SIZE(opts); i++) {
                const char *p = strstr(cmdline, opts[i]);

                if (p == cmdline || (p > cmdline && isspace(p[-1]))) {
                        cmdline_memmap_override = opts[i];
                        break;
                }
        }

        return efi_parse_options(cmdline);
}

static efi_status_t efi_decompress_kernel(unsigned long *kernel_entry,
                                          struct boot_params *boot_params)
{
        unsigned long virt_addr = LOAD_PHYSICAL_ADDR;
        unsigned long addr, alloc_size, entry;
        efi_status_t status;
        u32 seed[2] = {};

        boot_params_ptr = boot_params;

        /* determine the required size of the allocation */
        alloc_size = ALIGN(max_t(unsigned long, output_len, kernel_total_size),
                           MIN_KERNEL_ALIGN);

        if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && !efi_nokaslr) {
                u64 range = KERNEL_IMAGE_SIZE - LOAD_PHYSICAL_ADDR - kernel_total_size;
                static const efi_char16_t ami[] = L"American Megatrends";

                efi_get_seed(seed, sizeof(seed));

                virt_addr += (range * seed[1]) >> 32;
                virt_addr &= ~(CONFIG_PHYSICAL_ALIGN - 1);

                /*
                 * Older Dell systems with AMI UEFI firmware v2.0 may hang
                 * while decompressing the kernel if physical address
                 * randomization is enabled.
                 *
                 * https://bugzilla.kernel.org/show_bug.cgi?id=218173
                 */
                if (efi_system_table->hdr.revision <= EFI_2_00_SYSTEM_TABLE_REVISION &&
                    !memcmp(efistub_fw_vendor(), ami, sizeof(ami))) {
                        efi_debug("AMI firmware v2.0 or older detected - disabling physical KASLR\n");
                        seed[0] = 0;
                } else if (cmdline_memmap_override) {
                        efi_info("%s detected on the kernel command line - disabling physical KASLR\n",
                                 cmdline_memmap_override);
                        seed[0] = 0;
                }

                boot_params->hdr.loadflags |= KASLR_FLAG;
        }

        status = efi_random_alloc(alloc_size, CONFIG_PHYSICAL_ALIGN, &addr,
                                  seed[0], EFI_LOADER_CODE,
                                  LOAD_PHYSICAL_ADDR,
                                  EFI_X86_KERNEL_ALLOC_LIMIT);
        if (status != EFI_SUCCESS)
                return status;

        entry = decompress_kernel((void *)addr, virt_addr, error);
        if (entry == ULONG_MAX) {
                efi_free(alloc_size, addr);
                return EFI_LOAD_ERROR;
        }

        *kernel_entry = addr + entry;

        return efi_adjust_memory_range_protection(addr, kernel_text_size) ?:
               efi_adjust_memory_range_protection(addr + kernel_inittext_offset,
                                                  kernel_inittext_size);
}

static void __noreturn enter_kernel(unsigned long kernel_addr,
                                    struct boot_params *boot_params)
{
        /* enter decompressed kernel with boot_params pointer in RSI/ESI */
        asm("jmp *%0"::"r"(kernel_addr), "S"(boot_params));

        unreachable();
}

/*
 * On success, this routine will jump to the relocated image directly and never
 * return.  On failure, it will exit to the firmware via efi_exit() instead of
 * returning.
 */
void __noreturn efi_stub_entry(efi_handle_t handle,
                               efi_system_table_t *sys_table_arg,
                               struct boot_params *boot_params)

{
        efi_guid_t guid = EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID;
        const struct linux_efi_initrd *initrd = NULL;
        unsigned long kernel_entry;
        struct setup_header *hdr;
        efi_status_t status;

        efi_system_table = sys_table_arg;
        /* Check if we were booted by the EFI firmware */
        if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
                efi_exit(handle, EFI_INVALID_PARAMETER);

        if (!IS_ENABLED(CONFIG_EFI_HANDOVER_PROTOCOL) || !boot_params) {
                status = efi_allocate_bootparams(handle, &boot_params);
                if (status != EFI_SUCCESS)
                        efi_exit(handle, status);
        }

        hdr = &boot_params->hdr;

        if (have_unsupported_snp_features())
                efi_exit(handle, EFI_UNSUPPORTED);

        if (IS_ENABLED(CONFIG_EFI_DXE_MEM_ATTRIBUTES)) {
                efi_dxe_table = get_efi_config_table(EFI_DXE_SERVICES_TABLE_GUID);
                if (efi_dxe_table &&
                    efi_dxe_table->hdr.signature != EFI_DXE_SERVICES_TABLE_SIGNATURE) {
                        efi_warn("Ignoring DXE services table: invalid signature\n");
                        efi_dxe_table = NULL;
                }
        }

        /* grab the memory attributes protocol if it exists */
        efi_bs_call(locate_protocol, &guid, NULL, (void **)&memattr);

        status = efi_setup_5level_paging();
        if (status != EFI_SUCCESS) {
                efi_err("efi_setup_5level_paging() failed!\n");
                goto fail;
        }

#ifdef CONFIG_CMDLINE_BOOL
        status = parse_options(CONFIG_CMDLINE);
        if (status != EFI_SUCCESS) {
                efi_err("Failed to parse options\n");
                goto fail;
        }
#endif
        if (!IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) {
                unsigned long cmdline_paddr = ((u64)hdr->cmd_line_ptr |
                                               ((u64)boot_params->ext_cmd_line_ptr << 32));
                status = parse_options((char *)cmdline_paddr);
                if (status != EFI_SUCCESS) {
                        efi_err("Failed to parse options\n");
                        goto fail;
                }
        }

        if (efi_mem_encrypt > 0)
                hdr->xloadflags |= XLF_MEM_ENCRYPTION;

        status = efi_decompress_kernel(&kernel_entry, boot_params);
        if (status != EFI_SUCCESS) {
                efi_err("Failed to decompress kernel\n");
                goto fail;
        }

        /*
         * At this point, an initrd may already have been loaded by the
         * bootloader and passed via bootparams. We permit an initrd loaded
         * from the LINUX_EFI_INITRD_MEDIA_GUID device path to supersede it.
         *
         * If the device path is not present, any command-line initrd=
         * arguments will be processed only if image is not NULL, which will be
         * the case only if we were loaded via the PE entry point.
         */
        status = efi_load_initrd(image, hdr->initrd_addr_max, ULONG_MAX,
                                 &initrd);
        if (status != EFI_SUCCESS)
                goto fail;
        if (initrd && initrd->size > 0) {
                efi_set_u64_split(initrd->base, &hdr->ramdisk_image,
                                  &boot_params->ext_ramdisk_image);
                efi_set_u64_split(initrd->size, &hdr->ramdisk_size,
                                  &boot_params->ext_ramdisk_size);
        }


        /*
         * If the boot loader gave us a value for secure_boot then we use that,
         * otherwise we ask the BIOS.
         */
        if (boot_params->secure_boot == efi_secureboot_mode_unset)
                boot_params->secure_boot = efi_get_secureboot();

        /* Ask the firmware to clear memory on unclean shutdown */
        efi_enable_reset_attack_mitigation();

        efi_random_get_seed();

        efi_retrieve_eventlog();

        setup_graphics(boot_params);

        setup_efi_pci(boot_params);

        setup_quirks(boot_params);

        setup_unaccepted_memory();

        status = exit_boot(boot_params, handle);
        if (status != EFI_SUCCESS) {
                efi_err("exit_boot() failed!\n");
                goto fail;
        }

        /*
         * Call the SEV init code while still running with the firmware's
         * GDT/IDT, so #VC exceptions will be handled by EFI.
         */
        sev_enable(boot_params);

        efi_5level_switch();

        enter_kernel(kernel_entry, boot_params);
fail:
        efi_err("efi_stub_entry() failed!\n");

        efi_exit(handle, status);
}

efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
                                   efi_system_table_t *sys_table_arg)
{
        efi_stub_entry(handle, sys_table_arg, NULL);
}

#ifdef CONFIG_EFI_HANDOVER_PROTOCOL
void efi_handover_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
                        struct boot_params *boot_params)
{
        memset(_bss, 0, _ebss - _bss);
        efi_stub_entry(handle, sys_table_arg, boot_params);
}

#ifndef CONFIG_EFI_MIXED
extern __alias(efi_handover_entry)
void efi32_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
                      struct boot_params *boot_params);

extern __alias(efi_handover_entry)
void efi64_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg,
                      struct boot_params *boot_params);
#endif
#endif