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1// SPDX-License-Identifier: GPL-2.02 3#include <linux/efi.h>4#include <asm/efi.h>5 6#include "efistub.h"7 8/**9 * efi_low_alloc_above() - allocate pages at or above given address10 * @size: size of the memory area to allocate11 * @align: minimum alignment of the allocated memory area. It should12 * a power of two.13 * @addr: on exit the address of the allocated memory14 * @min: minimum address to used for the memory allocation15 *16 * Allocate at the lowest possible address that is not below @min as17 * EFI_LOADER_DATA. The allocated pages are aligned according to @align but at18 * least EFI_ALLOC_ALIGN. The first allocated page will not below the address19 * given by @min.20 *21 * Return: status code22 */23efi_status_t efi_low_alloc_above(unsigned long size, unsigned long align,24 unsigned long *addr, unsigned long min)25{26 struct efi_boot_memmap *map;27 efi_status_t status;28 unsigned long nr_pages;29 int i;30 31 status = efi_get_memory_map(&map, false);32 if (status != EFI_SUCCESS)33 goto fail;34 35 /*36 * Enforce minimum alignment that EFI or Linux requires when37 * requesting a specific address. We are doing page-based (or38 * larger) allocations, and both the address and size must meet39 * alignment constraints.40 */41 if (align < EFI_ALLOC_ALIGN)42 align = EFI_ALLOC_ALIGN;43 44 size = round_up(size, EFI_ALLOC_ALIGN);45 nr_pages = size / EFI_PAGE_SIZE;46 for (i = 0; i < map->map_size / map->desc_size; i++) {47 efi_memory_desc_t *desc;48 unsigned long m = (unsigned long)map->map;49 u64 start, end;50 51 desc = efi_memdesc_ptr(m, map->desc_size, i);52 53 if (desc->type != EFI_CONVENTIONAL_MEMORY)54 continue;55 56 if (efi_soft_reserve_enabled() &&57 (desc->attribute & EFI_MEMORY_SP))58 continue;59 60 if (desc->num_pages < nr_pages)61 continue;62 63 start = desc->phys_addr;64 end = start + desc->num_pages * EFI_PAGE_SIZE;65 66 if (start < min)67 start = min;68 69 start = round_up(start, align);70 if ((start + size) > end)71 continue;72 73 status = efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS,74 EFI_LOADER_DATA, nr_pages, &start);75 if (status == EFI_SUCCESS) {76 *addr = start;77 break;78 }79 }80 81 if (i == map->map_size / map->desc_size)82 status = EFI_NOT_FOUND;83 84 efi_bs_call(free_pool, map);85fail:86 return status;87}88 89/**90 * efi_relocate_kernel() - copy memory area91 * @image_addr: pointer to address of memory area to copy92 * @image_size: size of memory area to copy93 * @alloc_size: minimum size of memory to allocate, must be greater or94 * equal to image_size95 * @preferred_addr: preferred target address96 * @alignment: minimum alignment of the allocated memory area. It97 * should be a power of two.98 * @min_addr: minimum target address99 *100 * Copy a memory area to a newly allocated memory area aligned according101 * to @alignment but at least EFI_ALLOC_ALIGN. If the preferred address102 * is not available, the allocated address will not be below @min_addr.103 * On exit, @image_addr is updated to the target copy address that was used.104 *105 * This function is used to copy the Linux kernel verbatim. It does not apply106 * any relocation changes.107 *108 * Return: status code109 */110efi_status_t efi_relocate_kernel(unsigned long *image_addr,111 unsigned long image_size,112 unsigned long alloc_size,113 unsigned long preferred_addr,114 unsigned long alignment,115 unsigned long min_addr)116{117 unsigned long cur_image_addr;118 unsigned long new_addr = 0;119 efi_status_t status;120 unsigned long nr_pages;121 efi_physical_addr_t efi_addr = preferred_addr;122 123 if (!image_addr || !image_size || !alloc_size)124 return EFI_INVALID_PARAMETER;125 if (alloc_size < image_size)126 return EFI_INVALID_PARAMETER;127 128 cur_image_addr = *image_addr;129 130 /*131 * The EFI firmware loader could have placed the kernel image132 * anywhere in memory, but the kernel has restrictions on the133 * max physical address it can run at. Some architectures134 * also have a preferred address, so first try to relocate135 * to the preferred address. If that fails, allocate as low136 * as possible while respecting the required alignment.137 */138 nr_pages = round_up(alloc_size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;139 status = efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS,140 EFI_LOADER_DATA, nr_pages, &efi_addr);141 new_addr = efi_addr;142 /*143 * If preferred address allocation failed allocate as low as144 * possible.145 */146 if (status != EFI_SUCCESS) {147 status = efi_low_alloc_above(alloc_size, alignment, &new_addr,148 min_addr);149 }150 if (status != EFI_SUCCESS) {151 efi_err("Failed to allocate usable memory for kernel.\n");152 return status;153 }154 155 /*156 * We know source/dest won't overlap since both memory ranges157 * have been allocated by UEFI, so we can safely use memcpy.158 */159 memcpy((void *)new_addr, (void *)cur_image_addr, image_size);160 161 /* Return the new address of the relocated image. */162 *image_addr = new_addr;163 164 return status;165}166