// SPDX-License-Identifier: GPL-2.0
/*
 * Helper functions used by the EFI stub on multiple
 * architectures. This should be #included by the EFI stub
 * implementation files.
 *
 * Copyright 2011 Intel Corporation; author Matt Fleming
 */

#include <stdarg.h>

#include <linux/ctype.h>
#include <linux/efi.h>
#include <linux/kernel.h>
#include <linux/printk.h> /* For CONSOLE_LOGLEVEL_* */
#include <asm/efi.h>
#include <asm/setup.h>

#include "efistub.h"

bool efi_nochunk;
bool efi_nokaslr = !IS_ENABLED(CONFIG_RANDOMIZE_BASE);
bool efi_noinitrd;
int efi_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
bool efi_novamap;

static bool efi_nosoftreserve;
static bool efi_disable_pci_dma = IS_ENABLED(CONFIG_EFI_DISABLE_PCI_DMA);

bool __pure __efi_soft_reserve_enabled(void)
{
        return !efi_nosoftreserve;
}

/**
 * efi_char16_puts() - Write a UCS-2 encoded string to the console
 * @str:        UCS-2 encoded string
 */
void efi_char16_puts(efi_char16_t *str)
{
        efi_call_proto(efi_table_attr(efi_system_table, con_out),
                       output_string, str);
}

static
u32 utf8_to_utf32(const u8 **s8)
{
        u32 c32;
        u8 c0, cx;
        size_t clen, i;

        c0 = cx = *(*s8)++;
        /*
         * The position of the most-significant 0 bit gives us the length of
         * a multi-octet encoding.
         */
        for (clen = 0; cx & 0x80; ++clen)
                cx <<= 1;
        /*
         * If the 0 bit is in position 8, this is a valid single-octet
         * encoding. If the 0 bit is in position 7 or positions 1-3, the
         * encoding is invalid.
         * In either case, we just return the first octet.
         */
        if (clen < 2 || clen > 4)
                return c0;
        /* Get the bits from the first octet. */
        c32 = cx >> clen--;
        for (i = 0; i < clen; ++i) {
                /* Trailing octets must have 10 in most significant bits. */
                cx = (*s8)[i] ^ 0x80;
                if (cx & 0xc0)
                        return c0;
                c32 = (c32 << 6) | cx;
        }
        /*
         * Check for validity:
         * - The character must be in the Unicode range.
         * - It must not be a surrogate.
         * - It must be encoded using the correct number of octets.
         */
        if (c32 > 0x10ffff ||
            (c32 & 0xf800) == 0xd800 ||
            clen != (c32 >= 0x80) + (c32 >= 0x800) + (c32 >= 0x10000))
                return c0;
        *s8 += clen;
        return c32;
}

/**
 * efi_puts() - Write a UTF-8 encoded string to the console
 * @str:        UTF-8 encoded string
 */
void efi_puts(const char *str)
{
        efi_char16_t buf[128];
        size_t pos = 0, lim = ARRAY_SIZE(buf);
        const u8 *s8 = (const u8 *)str;
        u32 c32;

        while (*s8) {
                if (*s8 == '\n')
                        buf[pos++] = L'\r';
                c32 = utf8_to_utf32(&s8);
                if (c32 < 0x10000) {
                        /* Characters in plane 0 use a single word. */
                        buf[pos++] = c32;
                } else {
                        /*
                         * Characters in other planes encode into a surrogate
                         * pair.
                         */
                        buf[pos++] = (0xd800 - (0x10000 >> 10)) + (c32 >> 10);
                        buf[pos++] = 0xdc00 + (c32 & 0x3ff);
                }
                if (*s8 == '\0' || pos >= lim - 2) {
                        buf[pos] = L'\0';
                        efi_char16_puts(buf);
                        pos = 0;
                }
        }
}

/**
 * efi_printk() - Print a kernel message
 * @fmt:        format string
 *
 * The first letter of the format string is used to determine the logging level
 * of the message. If the level is less then the current EFI logging level, the
 * message is suppressed. The message will be truncated to 255 bytes.
 *
 * Return:      number of printed characters
 */
int efi_printk(const char *fmt, ...)
{
        char printf_buf[256];
        va_list args;
        int printed;
        int loglevel = printk_get_level(fmt);

        switch (loglevel) {
        case '0' ... '9':
                loglevel -= '0';
                break;
        default:
                /*
                 * Use loglevel -1 for cases where we just want to print to
                 * the screen.
                 */
                loglevel = -1;
                break;
        }

        if (loglevel >= efi_loglevel)
                return 0;

        if (loglevel >= 0)
                efi_puts("EFI stub: ");

        fmt = printk_skip_level(fmt);

        va_start(args, fmt);
        printed = vsnprintf(printf_buf, sizeof(printf_buf), fmt, args);
        va_end(args);

        efi_puts(printf_buf);
        if (printed >= sizeof(printf_buf)) {
                efi_puts("[Message truncated]\n");
                return -1;
        }

        return printed;
}

/**
 * efi_parse_options() - Parse EFI command line options
 * @cmdline:    kernel command line
 *
 * Parse the ASCII string @cmdline for EFI options, denoted by the efi=
 * option, e.g. efi=nochunk.
 *
 * It should be noted that efi= is parsed in two very different
 * environments, first in the early boot environment of the EFI boot
 * stub, and subsequently during the kernel boot.
 *
 * Return:      status code
 */
efi_status_t efi_parse_options(char const *cmdline)
{
        size_t len;
        efi_status_t status;
        char *str, *buf;

        if (!cmdline)
                return EFI_SUCCESS;

        len = strnlen(cmdline, COMMAND_LINE_SIZE - 1) + 1;
        status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, len, (void **)&buf);
        if (status != EFI_SUCCESS)
                return status;

        memcpy(buf, cmdline, len - 1);
        buf[len - 1] = '\0';
        str = skip_spaces(buf);

        while (*str) {
                char *param, *val;

                str = next_arg(str, &param, &val);
                if (!val && !strcmp(param, "--"))
                        break;

                if (!strcmp(param, "nokaslr")) {
                        efi_nokaslr = true;
                } else if (!strcmp(param, "quiet")) {
                        efi_loglevel = CONSOLE_LOGLEVEL_QUIET;
                } else if (!strcmp(param, "noinitrd")) {
                        efi_noinitrd = true;
                } else if (!strcmp(param, "efi") && val) {
                        efi_nochunk = parse_option_str(val, "nochunk");
                        efi_novamap = parse_option_str(val, "novamap");

                        efi_nosoftreserve = IS_ENABLED(CONFIG_EFI_SOFT_RESERVE) &&
                                            parse_option_str(val, "nosoftreserve");

                        if (parse_option_str(val, "disable_early_pci_dma"))
                                efi_disable_pci_dma = true;
                        if (parse_option_str(val, "no_disable_early_pci_dma"))
                                efi_disable_pci_dma = false;
                        if (parse_option_str(val, "debug"))
                                efi_loglevel = CONSOLE_LOGLEVEL_DEBUG;
                } else if (!strcmp(param, "video") &&
                           val && strstarts(val, "efifb:")) {
                        efi_parse_option_graphics(val + strlen("efifb:"));
                }
        }
        efi_bs_call(free_pool, buf);
        return EFI_SUCCESS;
}

/*
 * The EFI_LOAD_OPTION descriptor has the following layout:
 *      u32 Attributes;
 *      u16 FilePathListLength;
 *      u16 Description[];
 *      efi_device_path_protocol_t FilePathList[];
 *      u8 OptionalData[];
 *
 * This function validates and unpacks the variable-size data fields.
 */
static
bool efi_load_option_unpack(efi_load_option_unpacked_t *dest,
                            const efi_load_option_t *src, size_t size)
{
        const void *pos;
        u16 c;
        efi_device_path_protocol_t header;
        const efi_char16_t *description;
        const efi_device_path_protocol_t *file_path_list;

        if (size < offsetof(efi_load_option_t, variable_data))
                return false;
        pos = src->variable_data;
        size -= offsetof(efi_load_option_t, variable_data);

        if ((src->attributes & ~EFI_LOAD_OPTION_MASK) != 0)
                return false;

        /* Scan description. */
        description = pos;
        do {
                if (size < sizeof(c))
                        return false;
                c = *(const u16 *)pos;
                pos += sizeof(c);
                size -= sizeof(c);
        } while (c != L'\0');

        /* Scan file_path_list. */
        file_path_list = pos;
        do {
                if (size < sizeof(header))
                        return false;
                header = *(const efi_device_path_protocol_t *)pos;
                if (header.length < sizeof(header))
                        return false;
                if (size < header.length)
                        return false;
                pos += header.length;
                size -= header.length;
        } while ((header.type != EFI_DEV_END_PATH && header.type != EFI_DEV_END_PATH2) ||
                 (header.sub_type != EFI_DEV_END_ENTIRE));
        if (pos != (const void *)file_path_list + src->file_path_list_length)
                return false;

        dest->attributes = src->attributes;
        dest->file_path_list_length = src->file_path_list_length;
        dest->description = description;
        dest->file_path_list = file_path_list;
        dest->optional_data_size = size;
        dest->optional_data = size ? pos : NULL;

        return true;
}

/*
 * At least some versions of Dell firmware pass the entire contents of the
 * Boot#### variable, i.e. the EFI_LOAD_OPTION descriptor, rather than just the
 * OptionalData field.
 *
 * Detect this case and extract OptionalData.
 */
void efi_apply_loadoptions_quirk(const void **load_options, int *load_options_size)
{
        const efi_load_option_t *load_option = *load_options;
        efi_load_option_unpacked_t load_option_unpacked;

        if (!IS_ENABLED(CONFIG_X86))
                return;
        if (!load_option)
                return;
        if (*load_options_size < sizeof(*load_option))
                return;
        if ((load_option->attributes & ~EFI_LOAD_OPTION_BOOT_MASK) != 0)
                return;

        if (!efi_load_option_unpack(&load_option_unpacked, load_option, *load_options_size))
                return;

        efi_warn_once(FW_BUG "LoadOptions is an EFI_LOAD_OPTION descriptor\n");
        efi_warn_once(FW_BUG "Using OptionalData as a workaround\n");

        *load_options = load_option_unpacked.optional_data;
        *load_options_size = load_option_unpacked.optional_data_size;
}

/*
 * Convert the unicode UEFI command line to ASCII to pass to kernel.
 * Size of memory allocated return in *cmd_line_len.
 * Returns NULL on error.
 */
char *efi_convert_cmdline(efi_loaded_image_t *image, int *cmd_line_len)
{
        const u16 *s2;
        unsigned long cmdline_addr = 0;
        int options_chars = efi_table_attr(image, load_options_size);
        const u16 *options = efi_table_attr(image, load_options);
        int options_bytes = 0, safe_options_bytes = 0;  /* UTF-8 bytes */
        bool in_quote = false;
        efi_status_t status;

        efi_apply_loadoptions_quirk((const void **)&options, &options_chars);
        options_chars /= sizeof(*options);

        if (options) {
                s2 = options;
                while (options_bytes < COMMAND_LINE_SIZE && options_chars--) {
                        u16 c = *s2++;

                        if (c < 0x80) {
                                if (c == L'\0' || c == L'\n')
                                        break;
                                if (c == L'"')
                                        in_quote = !in_quote;
                                else if (!in_quote && isspace((char)c))
                                        safe_options_bytes = options_bytes;

                                options_bytes++;
                                continue;
                        }

                        /*
                         * Get the number of UTF-8 bytes corresponding to a
                         * UTF-16 character.
                         * The first part handles everything in the BMP.
                         */
                        options_bytes += 2 + (c >= 0x800);
                        /*
                         * Add one more byte for valid surrogate pairs. Invalid
                         * surrogates will be replaced with 0xfffd and take up
                         * only 3 bytes.
                         */
                        if ((c & 0xfc00) == 0xd800) {
                                /*
                                 * If the very last word is a high surrogate,
                                 * we must ignore it since we can't access the
                                 * low surrogate.
                                 */
                                if (!options_chars) {
                                        options_bytes -= 3;
                                } else if ((*s2 & 0xfc00) == 0xdc00) {
                                        options_bytes++;
                                        options_chars--;
                                        s2++;
                                }
                        }
                }
                if (options_bytes >= COMMAND_LINE_SIZE) {
                        options_bytes = safe_options_bytes;
                        efi_err("Command line is too long: truncated to %d bytes\n",
                                options_bytes);
                }
        }

        options_bytes++;        /* NUL termination */

        status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, options_bytes,
                             (void **)&cmdline_addr);
        if (status != EFI_SUCCESS)
                return NULL;

        snprintf((char *)cmdline_addr, options_bytes, "%.*ls",
                 options_bytes - 1, options);

        *cmd_line_len = options_bytes;
        return (char *)cmdline_addr;
}

/**
 * efi_exit_boot_services() - Exit boot services
 * @handle:     handle of the exiting image
 * @map:        pointer to receive the memory map
 * @priv:       argument to be passed to @priv_func
 * @priv_func:  function to process the memory map before exiting boot services
 *
 * Handle calling ExitBootServices according to the requirements set out by the
 * spec.  Obtains the current memory map, and returns that info after calling
 * ExitBootServices.  The client must specify a function to perform any
 * processing of the memory map data prior to ExitBootServices.  A client
 * specific structure may be passed to the function via priv.  The client
 * function may be called multiple times.
 *
 * Return:      status code
 */
efi_status_t efi_exit_boot_services(void *handle,
                                    struct efi_boot_memmap *map,
                                    void *priv,
                                    efi_exit_boot_map_processing priv_func)
{
        efi_status_t status;

        status = efi_get_memory_map(map);

        if (status != EFI_SUCCESS)
                goto fail;

        status = priv_func(map, priv);
        if (status != EFI_SUCCESS)
                goto free_map;

        if (efi_disable_pci_dma)
                efi_pci_disable_bridge_busmaster();

        status = efi_bs_call(exit_boot_services, handle, *map->key_ptr);

        if (status == EFI_INVALID_PARAMETER) {
                /*
                 * The memory map changed between efi_get_memory_map() and
                 * exit_boot_services().  Per the UEFI Spec v2.6, Section 6.4:
                 * EFI_BOOT_SERVICES.ExitBootServices we need to get the
                 * updated map, and try again.  The spec implies one retry
                 * should be sufficent, which is confirmed against the EDK2
                 * implementation.  Per the spec, we can only invoke
                 * get_memory_map() and exit_boot_services() - we cannot alloc
                 * so efi_get_memory_map() cannot be used, and we must reuse
                 * the buffer.  For all practical purposes, the headroom in the
                 * buffer should account for any changes in the map so the call
                 * to get_memory_map() is expected to succeed here.
                 */
                *map->map_size = *map->buff_size;
                status = efi_bs_call(get_memory_map,
                                     map->map_size,
                                     *map->map,
                                     map->key_ptr,
                                     map->desc_size,
                                     map->desc_ver);

                /* exit_boot_services() was called, thus cannot free */
                if (status != EFI_SUCCESS)
                        goto fail;

                status = priv_func(map, priv);
                /* exit_boot_services() was called, thus cannot free */
                if (status != EFI_SUCCESS)
                        goto fail;

                status = efi_bs_call(exit_boot_services, handle, *map->key_ptr);
        }

        /* exit_boot_services() was called, thus cannot free */
        if (status != EFI_SUCCESS)
                goto fail;

        return EFI_SUCCESS;

free_map:
        efi_bs_call(free_pool, *map->map);
fail:
        return status;
}

/**
 * get_efi_config_table() - retrieve UEFI configuration table
 * @guid:       GUID of the configuration table to be retrieved
 * Return:      pointer to the configuration table or NULL
 */
void *get_efi_config_table(efi_guid_t guid)
{
        unsigned long tables = efi_table_attr(efi_system_table, tables);
        int nr_tables = efi_table_attr(efi_system_table, nr_tables);
        int i;

        for (i = 0; i < nr_tables; i++) {
                efi_config_table_t *t = (void *)tables;

                if (efi_guidcmp(t->guid, guid) == 0)
                        return efi_table_attr(t, table);

                tables += efi_is_native() ? sizeof(efi_config_table_t)
                                          : sizeof(efi_config_table_32_t);
        }
        return NULL;
}

/*
 * The LINUX_EFI_INITRD_MEDIA_GUID vendor media device path below provides a way
 * for the firmware or bootloader to expose the initrd data directly to the stub
 * via the trivial LoadFile2 protocol, which is defined in the UEFI spec, and is
 * very easy to implement. It is a simple Linux initrd specific conduit between
 * kernel and firmware, allowing us to put the EFI stub (being part of the
 * kernel) in charge of where and when to load the initrd, while leaving it up
 * to the firmware to decide whether it needs to expose its filesystem hierarchy
 * via EFI protocols.
 */
static const struct {
        struct efi_vendor_dev_path      vendor;
        struct efi_generic_dev_path     end;
} __packed initrd_dev_path = {
        {
                {
                        EFI_DEV_MEDIA,
                        EFI_DEV_MEDIA_VENDOR,
                        sizeof(struct efi_vendor_dev_path),
                },
                LINUX_EFI_INITRD_MEDIA_GUID
        }, {
                EFI_DEV_END_PATH,
                EFI_DEV_END_ENTIRE,
                sizeof(struct efi_generic_dev_path)
        }
};

/**
 * efi_load_initrd_dev_path() - load the initrd from the Linux initrd device path
 * @load_addr:  pointer to store the address where the initrd was loaded
 * @load_size:  pointer to store the size of the loaded initrd
 * @max:        upper limit for the initrd memory allocation
 *
 * Return:
 * * %EFI_SUCCESS if the initrd was loaded successfully, in which
 *   case @load_addr and @load_size are assigned accordingly
 * * %EFI_NOT_FOUND if no LoadFile2 protocol exists on the initrd device path
 * * %EFI_INVALID_PARAMETER if load_addr == NULL or load_size == NULL
 * * %EFI_OUT_OF_RESOURCES if memory allocation failed
 * * %EFI_LOAD_ERROR in all other cases
 */
static
efi_status_t efi_load_initrd_dev_path(unsigned long *load_addr,
                                      unsigned long *load_size,
                                      unsigned long max)
{
        efi_guid_t lf2_proto_guid = EFI_LOAD_FILE2_PROTOCOL_GUID;
        efi_device_path_protocol_t *dp;
        efi_load_file2_protocol_t *lf2;
        unsigned long initrd_addr;
        unsigned long initrd_size;
        efi_handle_t handle;
        efi_status_t status;

        dp = (efi_device_path_protocol_t *)&initrd_dev_path;
        status = efi_bs_call(locate_device_path, &lf2_proto_guid, &dp, &handle);
        if (status != EFI_SUCCESS)
                return status;

        status = efi_bs_call(handle_protocol, handle, &lf2_proto_guid,
                             (void **)&lf2);
        if (status != EFI_SUCCESS)
                return status;

        status = efi_call_proto(lf2, load_file, dp, false, &initrd_size, NULL);
        if (status != EFI_BUFFER_TOO_SMALL)
                return EFI_LOAD_ERROR;

        status = efi_allocate_pages(initrd_size, &initrd_addr, max);
        if (status != EFI_SUCCESS)
                return status;

        status = efi_call_proto(lf2, load_file, dp, false, &initrd_size,
                                (void *)initrd_addr);
        if (status != EFI_SUCCESS) {
                efi_free(initrd_size, initrd_addr);
                return EFI_LOAD_ERROR;
        }

        *load_addr = initrd_addr;
        *load_size = initrd_size;
        return EFI_SUCCESS;
}

static
efi_status_t efi_load_initrd_cmdline(efi_loaded_image_t *image,
                                     unsigned long *load_addr,
                                     unsigned long *load_size,
                                     unsigned long soft_limit,
                                     unsigned long hard_limit)
{
        if (!IS_ENABLED(CONFIG_EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER) ||
            (IS_ENABLED(CONFIG_X86) && (!efi_is_native() || image == NULL))) {
                *load_addr = *load_size = 0;
                return EFI_SUCCESS;
        }

        return handle_cmdline_files(image, L"initrd=", sizeof(L"initrd=") - 2,
                                    soft_limit, hard_limit,
                                    load_addr, load_size);
}

/**
 * efi_load_initrd() - Load initial RAM disk
 * @image:      EFI loaded image protocol
 * @load_addr:  pointer to loaded initrd
 * @load_size:  size of loaded initrd
 * @soft_limit: preferred size of allocated memory for loading the initrd
 * @hard_limit: minimum size of allocated memory
 *
 * Return:      status code
 */
efi_status_t efi_load_initrd(efi_loaded_image_t *image,
                             unsigned long *load_addr,
                             unsigned long *load_size,
                             unsigned long soft_limit,
                             unsigned long hard_limit)
{
        efi_status_t status;

        if (!load_addr || !load_size)
                return EFI_INVALID_PARAMETER;

        status = efi_load_initrd_dev_path(load_addr, load_size, hard_limit);
        if (status == EFI_SUCCESS) {
                efi_info("Loaded initrd from LINUX_EFI_INITRD_MEDIA_GUID device path\n");
        } else if (status == EFI_NOT_FOUND) {
                status = efi_load_initrd_cmdline(image, load_addr, load_size,
                                                 soft_limit, hard_limit);
                if (status == EFI_SUCCESS && *load_size > 0)
                        efi_info("Loaded initrd from command line option\n");
        }

        return status;
}

/**
 * efi_wait_for_key() - Wait for key stroke
 * @usec:       number of microseconds to wait for key stroke
 * @key:        key entered
 *
 * Wait for up to @usec microseconds for a key stroke.
 *
 * Return:      status code, EFI_SUCCESS if key received
 */
efi_status_t efi_wait_for_key(unsigned long usec, efi_input_key_t *key)
{
        efi_event_t events[2], timer;
        unsigned long index;
        efi_simple_text_input_protocol_t *con_in;
        efi_status_t status;

        con_in = efi_table_attr(efi_system_table, con_in);
        if (!con_in)
                return EFI_UNSUPPORTED;
        efi_set_event_at(events, 0, efi_table_attr(con_in, wait_for_key));

        status = efi_bs_call(create_event, EFI_EVT_TIMER, 0, NULL, NULL, &timer);
        if (status != EFI_SUCCESS)
                return status;

        status = efi_bs_call(set_timer, timer, EfiTimerRelative,
                             EFI_100NSEC_PER_USEC * usec);
        if (status != EFI_SUCCESS)
                return status;
        efi_set_event_at(events, 1, timer);

        status = efi_bs_call(wait_for_event, 2, events, &index);
        if (status == EFI_SUCCESS) {
                if (index == 0)
                        status = efi_call_proto(con_in, read_keystroke, key);
                else
                        status = EFI_TIMEOUT;
        }

        efi_bs_call(close_event, timer);

        return status;
}