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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2013 Linaro Ltd; <roy.franz@linaro.org>
*/
#include <linux/efi.h>
#include <asm/efi.h>
#include "efistub.h"
efi_status_t check_platform_features(void)
{
int block;
/* non-LPAE kernels can run anywhere */
if (!IS_ENABLED(CONFIG_ARM_LPAE))
return EFI_SUCCESS;
/* LPAE kernels need compatible hardware */
block = cpuid_feature_extract(CPUID_EXT_MMFR0, 0);
if (block < 5) {
pr_efi_err("This LPAE kernel is not supported by your CPU\n");
return EFI_UNSUPPORTED;
}
return EFI_SUCCESS;
}
static efi_guid_t screen_info_guid = LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID;
struct screen_info *alloc_screen_info(void)
{
struct screen_info *si;
efi_status_t status;
/*
* Unlike on arm64, where we can directly fill out the screen_info
* structure from the stub, we need to allocate a buffer to hold
* its contents while we hand over to the kernel proper from the
* decompressor.
*/
status = efi_bs_call(allocate_pool, EFI_RUNTIME_SERVICES_DATA,
sizeof(*si), (void **)&si);
if (status != EFI_SUCCESS)
return NULL;
status = efi_bs_call(install_configuration_table,
&screen_info_guid, si);
if (status == EFI_SUCCESS)
return si;
efi_bs_call(free_pool, si);
return NULL;
}
void free_screen_info(struct screen_info *si)
{
if (!si)
return;
efi_bs_call(install_configuration_table, &screen_info_guid, NULL);
efi_bs_call(free_pool, si);
}
static efi_status_t reserve_kernel_base(unsigned long dram_base,
unsigned long *reserve_addr,
unsigned long *reserve_size)
{
efi_physical_addr_t alloc_addr;
efi_memory_desc_t *memory_map;
unsigned long nr_pages, map_size, desc_size, buff_size;
efi_status_t status;
unsigned long l;
struct efi_boot_memmap map = {
.map = &memory_map,
.map_size = &map_size,
.desc_size = &desc_size,
.desc_ver = NULL,
.key_ptr = NULL,
.buff_size = &buff_size,
};
/*
* Reserve memory for the uncompressed kernel image. This is
* all that prevents any future allocations from conflicting
* with the kernel. Since we can't tell from the compressed
* image how much DRAM the kernel actually uses (due to BSS
* size uncertainty) we allocate the maximum possible size.
* Do this very early, as prints can cause memory allocations
* that may conflict with this.
*/
alloc_addr = dram_base + MAX_UNCOMP_KERNEL_SIZE;
nr_pages = MAX_UNCOMP_KERNEL_SIZE / EFI_PAGE_SIZE;
status = efi_bs_call(allocate_pages, EFI_ALLOCATE_MAX_ADDRESS,
EFI_BOOT_SERVICES_DATA, nr_pages, &alloc_addr);
if (status == EFI_SUCCESS) {
if (alloc_addr == dram_base) {
*reserve_addr = alloc_addr;
*reserve_size = MAX_UNCOMP_KERNEL_SIZE;
return EFI_SUCCESS;
}
/*
* If we end up here, the allocation succeeded but starts below
* dram_base. This can only occur if the real base of DRAM is
* not a multiple of 128 MB, in which case dram_base will have
* been rounded up. Since this implies that a part of the region
* was already occupied, we need to fall through to the code
* below to ensure that the existing allocations don't conflict.
* For this reason, we use EFI_BOOT_SERVICES_DATA above and not
* EFI_LOADER_DATA, which we wouldn't able to distinguish from
* allocations that we want to disallow.
*/
}
/*
* If the allocation above failed, we may still be able to proceed:
* if the only allocations in the region are of types that will be
* released to the OS after ExitBootServices(), the decompressor can
* safely overwrite them.
*/
status = efi_get_memory_map(&map);
if (status != EFI_SUCCESS) {
pr_efi_err("reserve_kernel_base(): Unable to retrieve memory map.\n");
return status;
}
for (l = 0; l < map_size; l += desc_size) {
efi_memory_desc_t *desc;
u64 start, end;
desc = (void *)memory_map + l;
start = desc->phys_addr;
end = start + desc->num_pages * EFI_PAGE_SIZE;
/* Skip if entry does not intersect with region */
if (start >= dram_base + MAX_UNCOMP_KERNEL_SIZE ||
end <= dram_base)
continue;
switch (desc->type) {
case EFI_BOOT_SERVICES_CODE:
case EFI_BOOT_SERVICES_DATA:
/* Ignore types that are released to the OS anyway */
continue;
case EFI_CONVENTIONAL_MEMORY:
/* Skip soft reserved conventional memory */
if (efi_soft_reserve_enabled() &&
(desc->attribute & EFI_MEMORY_SP))
continue;
/*
* Reserve the intersection between this entry and the
* region.
*/
start = max(start, (u64)dram_base);
end = min(end, (u64)dram_base + MAX_UNCOMP_KERNEL_SIZE);
status = efi_bs_call(allocate_pages,
EFI_ALLOCATE_ADDRESS,
EFI_LOADER_DATA,
(end - start) / EFI_PAGE_SIZE,
&start);
if (status != EFI_SUCCESS) {
pr_efi_err("reserve_kernel_base(): alloc failed.\n");
goto out;
}
break;
case EFI_LOADER_CODE:
case EFI_LOADER_DATA:
/*
* These regions may be released and reallocated for
* another purpose (including EFI_RUNTIME_SERVICE_DATA)
* at any time during the execution of the OS loader,
* so we cannot consider them as safe.
*/
default:
/*
* Treat any other allocation in the region as unsafe */
status = EFI_OUT_OF_RESOURCES;
goto out;
}
}
status = EFI_SUCCESS;
out:
efi_bs_call(free_pool, memory_map);
return status;
}
efi_status_t handle_kernel_image(unsigned long *image_addr,
unsigned long *image_size,
unsigned long *reserve_addr,
unsigned long *reserve_size,
unsigned long dram_base,
efi_loaded_image_t *image)
{
unsigned long kernel_base;
efi_status_t status;
/* use a 16 MiB aligned base for the decompressed kernel */
kernel_base = round_up(dram_base, SZ_16M) + TEXT_OFFSET;
/*
* Note that some platforms (notably, the Raspberry Pi 2) put
* spin-tables and other pieces of firmware at the base of RAM,
* abusing the fact that the window of TEXT_OFFSET bytes at the
* base of the kernel image is only partially used at the moment.
* (Up to 5 pages are used for the swapper page tables)
*/
status = reserve_kernel_base(kernel_base - 5 * PAGE_SIZE, reserve_addr,
reserve_size);
if (status != EFI_SUCCESS) {
pr_efi_err("Unable to allocate memory for uncompressed kernel.\n");
return status;
}
*image_addr = kernel_base;
*image_size = 0;
return EFI_SUCCESS;
}
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