Staging
v0.7.0
v0.7.0
https://github.com/torvalds/linux
Tip revision: e49d033bddf5b565044e2abe4241353959bc9120 authored by Linus Torvalds on 04 April 2021, 21:15:36 UTC
Linux 5.12-rc6
Linux 5.12-rc6
Tip revision: e49d033
efi-stub-helper.c
// 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, ¶m, &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;
}