mirror of https://gitee.com/openkylin/linux.git
151 lines
3.4 KiB
C
151 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Support for extracting embedded firmware for peripherals from EFI code,
|
|
*
|
|
* Copyright (c) 2018 Hans de Goede <hdegoede@redhat.com>
|
|
*/
|
|
|
|
#include <linux/dmi.h>
|
|
#include <linux/efi.h>
|
|
#include <linux/efi_embedded_fw.h>
|
|
#include <linux/io.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/types.h>
|
|
#include <linux/vmalloc.h>
|
|
#include <crypto/sha.h>
|
|
|
|
/* Exported for use by lib/test_firmware.c only */
|
|
LIST_HEAD(efi_embedded_fw_list);
|
|
EXPORT_SYMBOL_GPL(efi_embedded_fw_list);
|
|
|
|
static bool checked_for_fw;
|
|
|
|
static const struct dmi_system_id * const embedded_fw_table[] = {
|
|
#ifdef CONFIG_TOUCHSCREEN_DMI
|
|
touchscreen_dmi_table,
|
|
#endif
|
|
NULL
|
|
};
|
|
|
|
/*
|
|
* Note the efi_check_for_embedded_firmwares() code currently makes the
|
|
* following 2 assumptions. This may needs to be revisited if embedded firmware
|
|
* is found where this is not true:
|
|
* 1) The firmware is only found in EFI_BOOT_SERVICES_CODE memory segments
|
|
* 2) The firmware always starts at an offset which is a multiple of 8 bytes
|
|
*/
|
|
static int __init efi_check_md_for_embedded_firmware(
|
|
efi_memory_desc_t *md, const struct efi_embedded_fw_desc *desc)
|
|
{
|
|
struct sha256_state sctx;
|
|
struct efi_embedded_fw *fw;
|
|
u8 sha256[32];
|
|
u64 i, size;
|
|
u8 *map;
|
|
|
|
size = md->num_pages << EFI_PAGE_SHIFT;
|
|
map = memremap(md->phys_addr, size, MEMREMAP_WB);
|
|
if (!map) {
|
|
pr_err("Error mapping EFI mem at %#llx\n", md->phys_addr);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
for (i = 0; (i + desc->length) <= size; i += 8) {
|
|
if (memcmp(map + i, desc->prefix, EFI_EMBEDDED_FW_PREFIX_LEN))
|
|
continue;
|
|
|
|
sha256_init(&sctx);
|
|
sha256_update(&sctx, map + i, desc->length);
|
|
sha256_final(&sctx, sha256);
|
|
if (memcmp(sha256, desc->sha256, 32) == 0)
|
|
break;
|
|
}
|
|
if ((i + desc->length) > size) {
|
|
memunmap(map);
|
|
return -ENOENT;
|
|
}
|
|
|
|
pr_info("Found EFI embedded fw '%s'\n", desc->name);
|
|
|
|
fw = kmalloc(sizeof(*fw), GFP_KERNEL);
|
|
if (!fw) {
|
|
memunmap(map);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
fw->data = kmemdup(map + i, desc->length, GFP_KERNEL);
|
|
memunmap(map);
|
|
if (!fw->data) {
|
|
kfree(fw);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
fw->name = desc->name;
|
|
fw->length = desc->length;
|
|
list_add(&fw->list, &efi_embedded_fw_list);
|
|
|
|
return 0;
|
|
}
|
|
|
|
void __init efi_check_for_embedded_firmwares(void)
|
|
{
|
|
const struct efi_embedded_fw_desc *fw_desc;
|
|
const struct dmi_system_id *dmi_id;
|
|
efi_memory_desc_t *md;
|
|
int i, r;
|
|
|
|
for (i = 0; embedded_fw_table[i]; i++) {
|
|
dmi_id = dmi_first_match(embedded_fw_table[i]);
|
|
if (!dmi_id)
|
|
continue;
|
|
|
|
fw_desc = dmi_id->driver_data;
|
|
|
|
/*
|
|
* In some drivers the struct driver_data contains may contain
|
|
* other driver specific data after the fw_desc struct; and
|
|
* the fw_desc struct itself may be empty, skip these.
|
|
*/
|
|
if (!fw_desc->name)
|
|
continue;
|
|
|
|
for_each_efi_memory_desc(md) {
|
|
if (md->type != EFI_BOOT_SERVICES_CODE)
|
|
continue;
|
|
|
|
r = efi_check_md_for_embedded_firmware(md, fw_desc);
|
|
if (r == 0)
|
|
break;
|
|
}
|
|
}
|
|
|
|
checked_for_fw = true;
|
|
}
|
|
|
|
int efi_get_embedded_fw(const char *name, const u8 **data, size_t *size)
|
|
{
|
|
struct efi_embedded_fw *iter, *fw = NULL;
|
|
|
|
if (!checked_for_fw) {
|
|
pr_warn("Warning %s called while we did not check for embedded fw\n",
|
|
__func__);
|
|
return -ENOENT;
|
|
}
|
|
|
|
list_for_each_entry(iter, &efi_embedded_fw_list, list) {
|
|
if (strcmp(name, iter->name) == 0) {
|
|
fw = iter;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!fw)
|
|
return -ENOENT;
|
|
|
|
*data = fw->data;
|
|
*size = fw->length;
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(efi_get_embedded_fw);
|