1 // SPDX-License-Identifier: GPL-2.0
2
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
10 static unsigned char zboot_heap[SZ_256K] __aligned(64);
11 static unsigned long free_mem_ptr, free_mem_end_ptr;
12
13 #define STATIC static
14 #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 memcpy
24 #define memcpy memcpy
25 #undef memmove
26 #define memmove memmove
27 #include "../../../../lib/decompress_unxz.c"
28 #elif defined(CONFIG_KERNEL_ZSTD)
29 #include "../../../../lib/decompress_unzstd.c"
30 #endif
31
32 extern char efi_zboot_header[];
33 extern char _gzdata_start[], _gzdata_end[];
34
error(char * x)35 static void error(char *x)
36 {
37 efi_err("EFI decompressor: %s\n", x);
38 }
39
alloc_preferred_address(unsigned long alloc_size)40 static unsigned long alloc_preferred_address(unsigned long alloc_size)
41 {
42 #ifdef EFI_KIMG_PREFERRED_ADDRESS
43 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 #endif
49 return ULONG_MAX;
50 }
51
efi_cache_sync_image(unsigned long image_base,unsigned long alloc_size)52 void __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 for
56 // executable code loaded into memory to be safe for execution.
57 }
58
alloc_screen_info(void)59 struct screen_info *alloc_screen_info(void)
60 {
61 return __alloc_screen_info();
62 }
63
64 asmlinkage efi_status_t __efiapi
efi_zboot_entry(efi_handle_t handle,efi_system_table_t * systab)65 efi_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 header
93 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 as
105 // allocating as low as possible
106 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
142 free_image:
143 efi_free(alloc_size, image_base);
144 free_cmdline:
145 efi_bs_call(free_pool, cmdline_ptr);
146 return status;
147 }
148