148 lines · c
1// SPDX-License-Identifier: GPL-2.02 3#include <linux/efi.h>4#include <linux/pe.h>5#include <asm/efi.h>6#include <linux/unaligned.h>7 8#include "efistub.h"9 10static unsigned char zboot_heap[SZ_256K] __aligned(64);11static unsigned long free_mem_ptr, free_mem_end_ptr;12 13#define STATIC static14#if defined(CONFIG_KERNEL_GZIP)15#include "../../../../lib/decompress_inflate.c"16#elif defined(CONFIG_KERNEL_LZ4)17#include "../../../../lib/decompress_unlz4.c"18#elif defined(CONFIG_KERNEL_LZMA)19#include "../../../../lib/decompress_unlzma.c"20#elif defined(CONFIG_KERNEL_LZO)21#include "../../../../lib/decompress_unlzo.c"22#elif defined(CONFIG_KERNEL_XZ)23#undef memcpy24#define memcpy memcpy25#undef memmove26#define memmove memmove27#include "../../../../lib/decompress_unxz.c"28#elif defined(CONFIG_KERNEL_ZSTD)29#include "../../../../lib/decompress_unzstd.c"30#endif31 32extern char efi_zboot_header[];33extern char _gzdata_start[], _gzdata_end[];34 35static void error(char *x)36{37 efi_err("EFI decompressor: %s\n", x);38}39 40static unsigned long alloc_preferred_address(unsigned long alloc_size)41{42#ifdef EFI_KIMG_PREFERRED_ADDRESS43 efi_physical_addr_t efi_addr = EFI_KIMG_PREFERRED_ADDRESS;44 45 if (efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,46 alloc_size / EFI_PAGE_SIZE, &efi_addr) == EFI_SUCCESS)47 return efi_addr;48#endif49 return ULONG_MAX;50}51 52void __weak efi_cache_sync_image(unsigned long image_base,53 unsigned long alloc_size)54{55 // Provided by the arch to perform the cache maintenance necessary for56 // executable code loaded into memory to be safe for execution.57}58 59struct screen_info *alloc_screen_info(void)60{61 return __alloc_screen_info();62}63 64asmlinkage efi_status_t __efiapi65efi_zboot_entry(efi_handle_t handle, efi_system_table_t *systab)66{67 unsigned long compressed_size = _gzdata_end - _gzdata_start;68 unsigned long image_base, alloc_size;69 efi_loaded_image_t *image;70 efi_status_t status;71 char *cmdline_ptr;72 int ret;73 74 WRITE_ONCE(efi_system_table, systab);75 76 free_mem_ptr = (unsigned long)&zboot_heap;77 free_mem_end_ptr = free_mem_ptr + sizeof(zboot_heap);78 79 status = efi_bs_call(handle_protocol, handle,80 &LOADED_IMAGE_PROTOCOL_GUID, (void **)&image);81 if (status != EFI_SUCCESS) {82 error("Failed to locate parent's loaded image protocol");83 return status;84 }85 86 status = efi_handle_cmdline(image, &cmdline_ptr);87 if (status != EFI_SUCCESS)88 return status;89 90 efi_info("Decompressing Linux Kernel...\n");91 92 // SizeOfImage from the compressee's PE/COFF header93 alloc_size = round_up(get_unaligned_le32(_gzdata_end - 4),94 EFI_ALLOC_ALIGN);95 96 // If the architecture has a preferred address for the image,97 // try that first.98 image_base = alloc_preferred_address(alloc_size);99 if (image_base == ULONG_MAX) {100 unsigned long min_kimg_align = efi_get_kimg_min_align();101 u32 seed = U32_MAX;102 103 if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {104 // Setting the random seed to 0x0 is the same as105 // allocating as low as possible106 seed = 0;107 } else if (efi_nokaslr) {108 efi_info("KASLR disabled on kernel command line\n");109 } else {110 status = efi_get_random_bytes(sizeof(seed), (u8 *)&seed);111 if (status == EFI_NOT_FOUND) {112 efi_info("EFI_RNG_PROTOCOL unavailable\n");113 efi_nokaslr = true;114 } else if (status != EFI_SUCCESS) {115 efi_err("efi_get_random_bytes() failed (0x%lx)\n",116 status);117 efi_nokaslr = true;118 }119 }120 121 status = efi_random_alloc(alloc_size, min_kimg_align, &image_base,122 seed, EFI_LOADER_CODE, 0, EFI_ALLOC_LIMIT);123 if (status != EFI_SUCCESS) {124 efi_err("Failed to allocate memory\n");125 goto free_cmdline;126 }127 }128 129 // Decompress the payload into the newly allocated buffer.130 ret = __decompress(_gzdata_start, compressed_size, NULL, NULL,131 (void *)image_base, alloc_size, NULL, error);132 if (ret < 0) {133 error("Decompression failed");134 status = EFI_DEVICE_ERROR;135 goto free_image;136 }137 138 efi_cache_sync_image(image_base, alloc_size);139 140 status = efi_stub_common(handle, image, image_base, cmdline_ptr);141 142free_image:143 efi_free(alloc_size, image_base);144free_cmdline:145 efi_bs_call(free_pool, cmdline_ptr);146 return status;147}148