256 lines
7.4 KiB
C
256 lines
7.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2013 Linaro Ltd; <roy.franz@linaro.org>
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*/
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#include <linux/efi.h>
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#include <asm/efi.h>
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#include "efistub.h"
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efi_status_t check_platform_features(efi_system_table_t *sys_table_arg)
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{
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int block;
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/* non-LPAE kernels can run anywhere */
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if (!IS_ENABLED(CONFIG_ARM_LPAE))
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return EFI_SUCCESS;
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/* LPAE kernels need compatible hardware */
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block = cpuid_feature_extract(CPUID_EXT_MMFR0, 0);
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if (block < 5) {
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pr_efi_err(sys_table_arg, "This LPAE kernel is not supported by your CPU\n");
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return EFI_UNSUPPORTED;
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}
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return EFI_SUCCESS;
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}
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static efi_guid_t screen_info_guid = LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID;
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struct screen_info *alloc_screen_info(efi_system_table_t *sys_table_arg)
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{
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struct screen_info *si;
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efi_status_t status;
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/*
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* Unlike on arm64, where we can directly fill out the screen_info
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* structure from the stub, we need to allocate a buffer to hold
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* its contents while we hand over to the kernel proper from the
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* decompressor.
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*/
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status = efi_call_early(allocate_pool, EFI_RUNTIME_SERVICES_DATA,
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sizeof(*si), (void **)&si);
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if (status != EFI_SUCCESS)
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return NULL;
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status = efi_call_early(install_configuration_table,
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&screen_info_guid, si);
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if (status == EFI_SUCCESS)
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return si;
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efi_call_early(free_pool, si);
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return NULL;
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}
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void free_screen_info(efi_system_table_t *sys_table_arg, struct screen_info *si)
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{
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if (!si)
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return;
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efi_call_early(install_configuration_table, &screen_info_guid, NULL);
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efi_call_early(free_pool, si);
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}
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static efi_status_t reserve_kernel_base(efi_system_table_t *sys_table_arg,
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unsigned long dram_base,
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unsigned long *reserve_addr,
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unsigned long *reserve_size)
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{
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efi_physical_addr_t alloc_addr;
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efi_memory_desc_t *memory_map;
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unsigned long nr_pages, map_size, desc_size, buff_size;
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efi_status_t status;
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unsigned long l;
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struct efi_boot_memmap map = {
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.map = &memory_map,
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.map_size = &map_size,
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.desc_size = &desc_size,
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.desc_ver = NULL,
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.key_ptr = NULL,
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.buff_size = &buff_size,
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};
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/*
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* Reserve memory for the uncompressed kernel image. This is
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* all that prevents any future allocations from conflicting
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* with the kernel. Since we can't tell from the compressed
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* image how much DRAM the kernel actually uses (due to BSS
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* size uncertainty) we allocate the maximum possible size.
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* Do this very early, as prints can cause memory allocations
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* that may conflict with this.
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*/
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alloc_addr = dram_base + MAX_UNCOMP_KERNEL_SIZE;
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nr_pages = MAX_UNCOMP_KERNEL_SIZE / EFI_PAGE_SIZE;
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status = efi_call_early(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,
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EFI_BOOT_SERVICES_DATA, nr_pages, &alloc_addr);
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if (status == EFI_SUCCESS) {
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if (alloc_addr == dram_base) {
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*reserve_addr = alloc_addr;
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*reserve_size = MAX_UNCOMP_KERNEL_SIZE;
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return EFI_SUCCESS;
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}
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/*
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* If we end up here, the allocation succeeded but starts below
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* dram_base. This can only occur if the real base of DRAM is
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* not a multiple of 128 MB, in which case dram_base will have
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* been rounded up. Since this implies that a part of the region
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* was already occupied, we need to fall through to the code
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* below to ensure that the existing allocations don't conflict.
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* For this reason, we use EFI_BOOT_SERVICES_DATA above and not
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* EFI_LOADER_DATA, which we wouldn't able to distinguish from
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* allocations that we want to disallow.
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*/
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}
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/*
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* If the allocation above failed, we may still be able to proceed:
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* if the only allocations in the region are of types that will be
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* released to the OS after ExitBootServices(), the decompressor can
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* safely overwrite them.
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*/
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status = efi_get_memory_map(sys_table_arg, &map);
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if (status != EFI_SUCCESS) {
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pr_efi_err(sys_table_arg,
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"reserve_kernel_base(): Unable to retrieve memory map.\n");
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return status;
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}
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for (l = 0; l < map_size; l += desc_size) {
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efi_memory_desc_t *desc;
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u64 start, end;
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desc = (void *)memory_map + l;
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start = desc->phys_addr;
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end = start + desc->num_pages * EFI_PAGE_SIZE;
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/* Skip if entry does not intersect with region */
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if (start >= dram_base + MAX_UNCOMP_KERNEL_SIZE ||
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end <= dram_base)
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continue;
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switch (desc->type) {
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case EFI_BOOT_SERVICES_CODE:
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case EFI_BOOT_SERVICES_DATA:
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/* Ignore types that are released to the OS anyway */
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continue;
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case EFI_CONVENTIONAL_MEMORY:
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/*
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* Reserve the intersection between this entry and the
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* region.
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*/
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start = max(start, (u64)dram_base);
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end = min(end, (u64)dram_base + MAX_UNCOMP_KERNEL_SIZE);
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status = efi_call_early(allocate_pages,
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EFI_ALLOCATE_ADDRESS,
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EFI_LOADER_DATA,
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(end - start) / EFI_PAGE_SIZE,
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&start);
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if (status != EFI_SUCCESS) {
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pr_efi_err(sys_table_arg,
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"reserve_kernel_base(): alloc failed.\n");
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goto out;
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}
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break;
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case EFI_LOADER_CODE:
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case EFI_LOADER_DATA:
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/*
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* These regions may be released and reallocated for
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* another purpose (including EFI_RUNTIME_SERVICE_DATA)
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* at any time during the execution of the OS loader,
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* so we cannot consider them as safe.
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*/
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default:
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/*
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* Treat any other allocation in the region as unsafe */
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status = EFI_OUT_OF_RESOURCES;
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goto out;
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}
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}
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status = EFI_SUCCESS;
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out:
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efi_call_early(free_pool, memory_map);
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return status;
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}
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efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
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unsigned long *image_addr,
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unsigned long *image_size,
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unsigned long *reserve_addr,
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unsigned long *reserve_size,
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unsigned long dram_base,
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efi_loaded_image_t *image)
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{
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unsigned long kernel_base;
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efi_status_t status;
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/*
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* Verify that the DRAM base address is compatible with the ARM
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* boot protocol, which determines the base of DRAM by masking
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* off the low 27 bits of the address at which the zImage is
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* loaded. These assumptions are made by the decompressor,
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* before any memory map is available.
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*/
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kernel_base = round_up(dram_base, SZ_128M);
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/*
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* Note that some platforms (notably, the Raspberry Pi 2) put
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* spin-tables and other pieces of firmware at the base of RAM,
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* abusing the fact that the window of TEXT_OFFSET bytes at the
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* base of the kernel image is only partially used at the moment.
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* (Up to 5 pages are used for the swapper page tables)
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*/
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kernel_base += TEXT_OFFSET - 5 * PAGE_SIZE;
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status = reserve_kernel_base(sys_table, kernel_base, reserve_addr,
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reserve_size);
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if (status != EFI_SUCCESS) {
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pr_efi_err(sys_table, "Unable to allocate memory for uncompressed kernel.\n");
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return status;
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}
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/*
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* Relocate the zImage, so that it appears in the lowest 128 MB
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* memory window.
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*/
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*image_size = image->image_size;
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status = efi_relocate_kernel(sys_table, image_addr, *image_size,
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*image_size,
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kernel_base + MAX_UNCOMP_KERNEL_SIZE, 0, 0);
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if (status != EFI_SUCCESS) {
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pr_efi_err(sys_table, "Failed to relocate kernel.\n");
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efi_free(sys_table, *reserve_size, *reserve_addr);
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*reserve_size = 0;
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return status;
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}
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/*
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* Check to see if we were able to allocate memory low enough
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* in memory. The kernel determines the base of DRAM from the
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* address at which the zImage is loaded.
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*/
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if (*image_addr + *image_size > dram_base + ZIMAGE_OFFSET_LIMIT) {
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pr_efi_err(sys_table, "Failed to relocate kernel, no low memory available.\n");
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efi_free(sys_table, *reserve_size, *reserve_addr);
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*reserve_size = 0;
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efi_free(sys_table, *image_size, *image_addr);
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*image_size = 0;
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return EFI_LOAD_ERROR;
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}
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return EFI_SUCCESS;
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}
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