1 /*
2  * Copyright (C) 2013 Linaro Ltd;  <roy.franz@linaro.org>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  *
8  */
9 #include <linux/efi.h>
10 #include <asm/efi.h>
11 
12 efi_status_t check_platform_features(efi_system_table_t *sys_table_arg)
13 {
14 	int block;
15 
16 	/* non-LPAE kernels can run anywhere */
17 	if (!IS_ENABLED(CONFIG_ARM_LPAE))
18 		return EFI_SUCCESS;
19 
20 	/* LPAE kernels need compatible hardware */
21 	block = cpuid_feature_extract(CPUID_EXT_MMFR0, 0);
22 	if (block < 5) {
23 		pr_efi_err(sys_table_arg, "This LPAE kernel is not supported by your CPU\n");
24 		return EFI_UNSUPPORTED;
25 	}
26 	return EFI_SUCCESS;
27 }
28 
29 static efi_guid_t screen_info_guid = LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID;
30 
31 struct screen_info *alloc_screen_info(efi_system_table_t *sys_table_arg)
32 {
33 	struct screen_info *si;
34 	efi_status_t status;
35 
36 	/*
37 	 * Unlike on arm64, where we can directly fill out the screen_info
38 	 * structure from the stub, we need to allocate a buffer to hold
39 	 * its contents while we hand over to the kernel proper from the
40 	 * decompressor.
41 	 */
42 	status = efi_call_early(allocate_pool, EFI_RUNTIME_SERVICES_DATA,
43 				sizeof(*si), (void **)&si);
44 
45 	if (status != EFI_SUCCESS)
46 		return NULL;
47 
48 	status = efi_call_early(install_configuration_table,
49 				&screen_info_guid, si);
50 	if (status == EFI_SUCCESS)
51 		return si;
52 
53 	efi_call_early(free_pool, si);
54 	return NULL;
55 }
56 
57 void free_screen_info(efi_system_table_t *sys_table_arg, struct screen_info *si)
58 {
59 	if (!si)
60 		return;
61 
62 	efi_call_early(install_configuration_table, &screen_info_guid, NULL);
63 	efi_call_early(free_pool, si);
64 }
65 
66 efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
67 				 unsigned long *image_addr,
68 				 unsigned long *image_size,
69 				 unsigned long *reserve_addr,
70 				 unsigned long *reserve_size,
71 				 unsigned long dram_base,
72 				 efi_loaded_image_t *image)
73 {
74 	unsigned long nr_pages;
75 	efi_status_t status;
76 	/* Use alloc_addr to tranlsate between types */
77 	efi_physical_addr_t alloc_addr;
78 
79 	/*
80 	 * Verify that the DRAM base address is compatible with the ARM
81 	 * boot protocol, which determines the base of DRAM by masking
82 	 * off the low 27 bits of the address at which the zImage is
83 	 * loaded. These assumptions are made by the decompressor,
84 	 * before any memory map is available.
85 	 */
86 	dram_base = round_up(dram_base, SZ_128M);
87 
88 	/*
89 	 * Reserve memory for the uncompressed kernel image. This is
90 	 * all that prevents any future allocations from conflicting
91 	 * with the kernel. Since we can't tell from the compressed
92 	 * image how much DRAM the kernel actually uses (due to BSS
93 	 * size uncertainty) we allocate the maximum possible size.
94 	 * Do this very early, as prints can cause memory allocations
95 	 * that may conflict with this.
96 	 */
97 	alloc_addr = dram_base;
98 	*reserve_size = MAX_UNCOMP_KERNEL_SIZE;
99 	nr_pages = round_up(*reserve_size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE;
100 	status = sys_table->boottime->allocate_pages(EFI_ALLOCATE_ADDRESS,
101 						     EFI_LOADER_DATA,
102 						     nr_pages, &alloc_addr);
103 	if (status != EFI_SUCCESS) {
104 		*reserve_size = 0;
105 		pr_efi_err(sys_table, "Unable to allocate memory for uncompressed kernel.\n");
106 		return status;
107 	}
108 	*reserve_addr = alloc_addr;
109 
110 	/*
111 	 * Relocate the zImage, so that it appears in the lowest 128 MB
112 	 * memory window.
113 	 */
114 	*image_size = image->image_size;
115 	status = efi_relocate_kernel(sys_table, image_addr, *image_size,
116 				     *image_size,
117 				     dram_base + MAX_UNCOMP_KERNEL_SIZE, 0);
118 	if (status != EFI_SUCCESS) {
119 		pr_efi_err(sys_table, "Failed to relocate kernel.\n");
120 		efi_free(sys_table, *reserve_size, *reserve_addr);
121 		*reserve_size = 0;
122 		return status;
123 	}
124 
125 	/*
126 	 * Check to see if we were able to allocate memory low enough
127 	 * in memory. The kernel determines the base of DRAM from the
128 	 * address at which the zImage is loaded.
129 	 */
130 	if (*image_addr + *image_size > dram_base + ZIMAGE_OFFSET_LIMIT) {
131 		pr_efi_err(sys_table, "Failed to relocate kernel, no low memory available.\n");
132 		efi_free(sys_table, *reserve_size, *reserve_addr);
133 		*reserve_size = 0;
134 		efi_free(sys_table, *image_size, *image_addr);
135 		*image_size = 0;
136 		return EFI_LOAD_ERROR;
137 	}
138 	return EFI_SUCCESS;
139 }
140