2 * Copyright (C) 2013, 2014 Linaro Ltd; <roy.franz@linaro.org>
4 * This file implements the EFI boot stub for the arm64 kernel.
5 * Adapted from ARM version by Mark Salter <msalter@redhat.com>
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.
12 #include <linux/efi.h>
14 #include <asm/sections.h>
15 #include <asm/sysreg.h>
19 efi_status_t check_platform_features(efi_system_table_t *sys_table_arg)
23 /* UEFI mandates support for 4 KB granularity, no need to check */
24 if (IS_ENABLED(CONFIG_ARM64_4K_PAGES))
27 tg = (read_cpuid(ID_AA64MMFR0_EL1) >> ID_AA64MMFR0_TGRAN_SHIFT) & 0xf;
28 if (tg != ID_AA64MMFR0_TGRAN_SUPPORTED) {
29 if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
30 pr_efi_err(sys_table_arg, "This 64 KB granular kernel is not supported by your CPU\n");
32 pr_efi_err(sys_table_arg, "This 16 KB granular kernel is not supported by your CPU\n");
33 return EFI_UNSUPPORTED;
38 efi_status_t handle_kernel_image(efi_system_table_t *sys_table_arg,
39 unsigned long *image_addr,
40 unsigned long *image_size,
41 unsigned long *reserve_addr,
42 unsigned long *reserve_size,
43 unsigned long dram_base,
44 efi_loaded_image_t *image)
47 unsigned long kernel_size, kernel_memsize = 0;
48 void *old_image_addr = (void *)*image_addr;
49 unsigned long preferred_offset;
52 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
54 status = efi_get_random_bytes(sys_table_arg,
57 if (status == EFI_NOT_FOUND) {
58 pr_efi(sys_table_arg, "EFI_RNG_PROTOCOL unavailable, no randomness supplied\n");
59 } else if (status != EFI_SUCCESS) {
60 pr_efi_err(sys_table_arg, "efi_get_random_bytes() failed\n");
64 pr_efi(sys_table_arg, "KASLR disabled on kernel command line\n");
69 * The preferred offset of the kernel Image is TEXT_OFFSET bytes beyond
70 * a 2 MB aligned base, which itself may be lower than dram_base, as
71 * long as the resulting offset equals or exceeds it.
73 preferred_offset = round_down(dram_base, MIN_KIMG_ALIGN) + TEXT_OFFSET;
74 if (preferred_offset < dram_base)
75 preferred_offset += MIN_KIMG_ALIGN;
77 kernel_size = _edata - _text;
78 kernel_memsize = kernel_size + (_end - _edata);
80 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && phys_seed != 0) {
82 * If CONFIG_DEBUG_ALIGN_RODATA is not set, produce a
83 * displacement in the interval [0, MIN_KIMG_ALIGN) that
84 * is a multiple of the minimal segment alignment (SZ_64K)
86 u32 mask = (MIN_KIMG_ALIGN - 1) & ~(SZ_64K - 1);
87 u32 offset = !IS_ENABLED(CONFIG_DEBUG_ALIGN_RODATA) ?
88 (phys_seed >> 32) & mask : TEXT_OFFSET;
91 * If KASLR is enabled, and we have some randomness available,
92 * locate the kernel at a randomized offset in physical memory.
94 *reserve_size = kernel_memsize + offset;
95 status = efi_random_alloc(sys_table_arg, *reserve_size,
96 MIN_KIMG_ALIGN, reserve_addr,
99 *image_addr = *reserve_addr + offset;
102 * Else, try a straight allocation at the preferred offset.
103 * This will work around the issue where, if dram_base == 0x0,
104 * efi_low_alloc() refuses to allocate at 0x0 (to prevent the
105 * address of the allocation to be mistaken for a FAIL return
106 * value or a NULL pointer). It will also ensure that, on
107 * platforms where the [dram_base, dram_base + TEXT_OFFSET)
108 * interval is partially occupied by the firmware (like on APM
109 * Mustang), we can still place the kernel at the address
110 * 'dram_base + TEXT_OFFSET'.
112 if (*image_addr == preferred_offset)
115 *image_addr = *reserve_addr = preferred_offset;
116 *reserve_size = round_up(kernel_memsize, EFI_ALLOC_ALIGN);
118 status = efi_call_early(allocate_pages, EFI_ALLOCATE_ADDRESS,
120 *reserve_size / EFI_PAGE_SIZE,
121 (efi_physical_addr_t *)reserve_addr);
124 if (status != EFI_SUCCESS) {
125 *reserve_size = kernel_memsize + TEXT_OFFSET;
126 status = efi_low_alloc(sys_table_arg, *reserve_size,
127 MIN_KIMG_ALIGN, reserve_addr);
129 if (status != EFI_SUCCESS) {
130 pr_efi_err(sys_table_arg, "Failed to relocate kernel\n");
134 *image_addr = *reserve_addr + TEXT_OFFSET;
136 memcpy((void *)*image_addr, old_image_addr, kernel_size);