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3c7f2550 MS |
1 | /* |
2 | * Copyright (C) 2013, 2014 Linaro Ltd; <roy.franz@linaro.org> | |
3 | * | |
4 | * This file implements the EFI boot stub for the arm64 kernel. | |
5 | * Adapted from ARM version by Mark Salter <msalter@redhat.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | */ | |
12 | #include <linux/efi.h> | |
a13b0077 | 13 | #include <asm/efi.h> |
3c7f2550 | 14 | #include <asm/sections.h> |
42b55734 | 15 | #include <asm/sysreg.h> |
3c7f2550 | 16 | |
2b5fe07a AB |
17 | #include "efistub.h" |
18 | ||
19 | extern bool __nokaslr; | |
20 | ||
42b55734 AB |
21 | efi_status_t check_platform_features(efi_system_table_t *sys_table_arg) |
22 | { | |
23 | u64 tg; | |
24 | ||
25 | /* UEFI mandates support for 4 KB granularity, no need to check */ | |
26 | if (IS_ENABLED(CONFIG_ARM64_4K_PAGES)) | |
27 | return EFI_SUCCESS; | |
28 | ||
29 | tg = (read_cpuid(ID_AA64MMFR0_EL1) >> ID_AA64MMFR0_TGRAN_SHIFT) & 0xf; | |
30 | if (tg != ID_AA64MMFR0_TGRAN_SUPPORTED) { | |
31 | if (IS_ENABLED(CONFIG_ARM64_64K_PAGES)) | |
32 | pr_efi_err(sys_table_arg, "This 64 KB granular kernel is not supported by your CPU\n"); | |
33 | else | |
34 | pr_efi_err(sys_table_arg, "This 16 KB granular kernel is not supported by your CPU\n"); | |
35 | return EFI_UNSUPPORTED; | |
36 | } | |
37 | return EFI_SUCCESS; | |
38 | } | |
3c7f2550 | 39 | |
dae31fd2 AB |
40 | efi_status_t handle_kernel_image(efi_system_table_t *sys_table_arg, |
41 | unsigned long *image_addr, | |
42 | unsigned long *image_size, | |
43 | unsigned long *reserve_addr, | |
44 | unsigned long *reserve_size, | |
45 | unsigned long dram_base, | |
46 | efi_loaded_image_t *image) | |
3c7f2550 MS |
47 | { |
48 | efi_status_t status; | |
49 | unsigned long kernel_size, kernel_memsize = 0; | |
e38457c3 | 50 | void *old_image_addr = (void *)*image_addr; |
73effccb | 51 | unsigned long preferred_offset; |
2b5fe07a AB |
52 | u64 phys_seed = 0; |
53 | ||
54 | if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { | |
55 | if (!__nokaslr) { | |
56 | status = efi_get_random_bytes(sys_table_arg, | |
57 | sizeof(phys_seed), | |
58 | (u8 *)&phys_seed); | |
59 | if (status == EFI_NOT_FOUND) { | |
60 | pr_efi(sys_table_arg, "EFI_RNG_PROTOCOL unavailable, no randomness supplied\n"); | |
61 | } else if (status != EFI_SUCCESS) { | |
62 | pr_efi_err(sys_table_arg, "efi_get_random_bytes() failed\n"); | |
63 | return status; | |
64 | } | |
65 | } else { | |
66 | pr_efi(sys_table_arg, "KASLR disabled on kernel command line\n"); | |
67 | } | |
68 | } | |
73effccb AB |
69 | |
70 | /* | |
71 | * The preferred offset of the kernel Image is TEXT_OFFSET bytes beyond | |
72 | * a 2 MB aligned base, which itself may be lower than dram_base, as | |
73 | * long as the resulting offset equals or exceeds it. | |
74 | */ | |
2b5fe07a | 75 | preferred_offset = round_down(dram_base, MIN_KIMG_ALIGN) + TEXT_OFFSET; |
73effccb | 76 | if (preferred_offset < dram_base) |
2b5fe07a | 77 | preferred_offset += MIN_KIMG_ALIGN; |
3c7f2550 | 78 | |
3c7f2550 | 79 | kernel_size = _edata - _text; |
2b5fe07a AB |
80 | kernel_memsize = kernel_size + (_end - _edata); |
81 | ||
82 | if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && phys_seed != 0) { | |
6f26b367 AB |
83 | /* |
84 | * If CONFIG_DEBUG_ALIGN_RODATA is not set, produce a | |
85 | * displacement in the interval [0, MIN_KIMG_ALIGN) that | |
86 | * is a multiple of the minimal segment alignment (SZ_64K) | |
87 | */ | |
88 | u32 mask = (MIN_KIMG_ALIGN - 1) & ~(SZ_64K - 1); | |
89 | u32 offset = !IS_ENABLED(CONFIG_DEBUG_ALIGN_RODATA) ? | |
90 | (phys_seed >> 32) & mask : TEXT_OFFSET; | |
91 | ||
2b5fe07a AB |
92 | /* |
93 | * If KASLR is enabled, and we have some randomness available, | |
94 | * locate the kernel at a randomized offset in physical memory. | |
95 | */ | |
6f26b367 | 96 | *reserve_size = kernel_memsize + offset; |
2b5fe07a AB |
97 | status = efi_random_alloc(sys_table_arg, *reserve_size, |
98 | MIN_KIMG_ALIGN, reserve_addr, | |
6f26b367 | 99 | (u32)phys_seed); |
e38457c3 | 100 | |
6f26b367 | 101 | *image_addr = *reserve_addr + offset; |
2b5fe07a | 102 | } else { |
e38457c3 | 103 | /* |
2b5fe07a | 104 | * Else, try a straight allocation at the preferred offset. |
e38457c3 AB |
105 | * This will work around the issue where, if dram_base == 0x0, |
106 | * efi_low_alloc() refuses to allocate at 0x0 (to prevent the | |
107 | * address of the allocation to be mistaken for a FAIL return | |
108 | * value or a NULL pointer). It will also ensure that, on | |
109 | * platforms where the [dram_base, dram_base + TEXT_OFFSET) | |
110 | * interval is partially occupied by the firmware (like on APM | |
111 | * Mustang), we can still place the kernel at the address | |
112 | * 'dram_base + TEXT_OFFSET'. | |
113 | */ | |
2b5fe07a AB |
114 | if (*image_addr == preferred_offset) |
115 | return EFI_SUCCESS; | |
116 | ||
73effccb | 117 | *image_addr = *reserve_addr = preferred_offset; |
2b5fe07a AB |
118 | *reserve_size = round_up(kernel_memsize, EFI_ALLOC_ALIGN); |
119 | ||
e38457c3 | 120 | status = efi_call_early(allocate_pages, EFI_ALLOCATE_ADDRESS, |
2b5fe07a AB |
121 | EFI_LOADER_DATA, |
122 | *reserve_size / EFI_PAGE_SIZE, | |
e38457c3 | 123 | (efi_physical_addr_t *)reserve_addr); |
2b5fe07a | 124 | } |
e38457c3 | 125 | |
2b5fe07a AB |
126 | if (status != EFI_SUCCESS) { |
127 | *reserve_size = kernel_memsize + TEXT_OFFSET; | |
128 | status = efi_low_alloc(sys_table_arg, *reserve_size, | |
129 | MIN_KIMG_ALIGN, reserve_addr); | |
130 | ||
131 | if (status != EFI_SUCCESS) { | |
132 | pr_efi_err(sys_table_arg, "Failed to relocate kernel\n"); | |
133 | *reserve_size = 0; | |
134 | return status; | |
3c7f2550 | 135 | } |
2b5fe07a | 136 | *image_addr = *reserve_addr + TEXT_OFFSET; |
3c7f2550 | 137 | } |
2b5fe07a | 138 | memcpy((void *)*image_addr, old_image_addr, kernel_size); |
3c7f2550 MS |
139 | |
140 | return EFI_SUCCESS; | |
141 | } |