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// SPDX-License-Identifier: GPL-2.0-only
/*
* EFI stub implementation that is shared by arm and arm64 architectures.
* This should be #included by the EFI stub implementation files.
*
* Copyright (C) 2013,2014 Linaro Limited
* Roy Franz <roy.franz@linaro.org
* Copyright (C) 2013 Red Hat, Inc.
* Mark Salter <msalter@redhat.com>
*/
#include <linux/efi.h>
#include <asm/efi.h>
#include "efistub.h"
/*
* This is the base address at which to start allocating virtual memory ranges
* for UEFI Runtime Services.
*
* For ARM/ARM64:
* This is in the low TTBR0 range so that we can use
* any allocation we choose, and eliminate the risk of a conflict after kexec.
* The value chosen is the largest non-zero power of 2 suitable for this purpose
* both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can
* be mapped efficiently.
* Since 32-bit ARM could potentially execute with a 1G/3G user/kernel split,
* map everything below 1 GB. (512 MB is a reasonable upper bound for the
* entire footprint of the UEFI runtime services memory regions)
*
* For RISC-V:
* There is no specific reason for which, this address (512MB) can't be used
* EFI runtime virtual address for RISC-V. It also helps to use EFI runtime
* services on both RV32/RV64. Keep the same runtime virtual address for RISC-V
* as well to minimize the code churn.
*/
#define EFI_RT_VIRTUAL_BASE SZ_512M
/*
* Some architectures map the EFI regions into the kernel's linear map using a
* fixed offset.
*/
#ifndef EFI_RT_VIRTUAL_OFFSET
#define EFI_RT_VIRTUAL_OFFSET 0
#endif
static u64 virtmap_base = EFI_RT_VIRTUAL_BASE;
static bool flat_va_mapping = (EFI_RT_VIRTUAL_OFFSET != 0);
void __weak free_screen_info(struct screen_info *si)
{
}
static struct screen_info *setup_graphics(void)
{
efi_guid_t gop_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
efi_status_t status;
unsigned long size;
void **gop_handle = NULL;
struct screen_info *si = NULL;
size = 0;
status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL,
&gop_proto, NULL, &size, gop_handle);
if (status == EFI_BUFFER_TOO_SMALL) {
si = alloc_screen_info();
if (!si)
return NULL;
status = efi_setup_gop(si, &gop_proto, size);
if (status != EFI_SUCCESS) {
free_screen_info(si);
return NULL;
}
}
return si;
}
static void install_memreserve_table(void)
{
struct linux_efi_memreserve *rsv;
efi_guid_t memreserve_table_guid = LINUX_EFI_MEMRESERVE_TABLE_GUID;
efi_status_t status;
status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, sizeof(*rsv),
(void **)&rsv);
if (status != EFI_SUCCESS) {
efi_err("Failed to allocate memreserve entry!\n");
return;
}
rsv->next = 0;
rsv->size = 0;
atomic_set(&rsv->count, 0);
status = efi_bs_call(install_configuration_table,
&memreserve_table_guid, rsv);
if (status != EFI_SUCCESS)
efi_err("Failed to install memreserve config table!\n");
}
static u32 get_supported_rt_services(void)
{
const efi_rt_properties_table_t *rt_prop_table;
u32 supported = EFI_RT_SUPPORTED_ALL;
rt_prop_table = get_efi_config_table(EFI_RT_PROPERTIES_TABLE_GUID);
if (rt_prop_table)
supported &= rt_prop_table->runtime_services_supported;
return supported;
}
efi_status_t efi_handle_cmdline(efi_loaded_image_t *image, char **cmdline_ptr)
{
int cmdline_size = 0;
efi_status_t status;
char *cmdline;
/*
* Get the command line from EFI, using the LOADED_IMAGE
* protocol. We are going to copy the command line into the
* device tree, so this can be allocated anywhere.
*/
cmdline = efi_convert_cmdline(image, &cmdline_size);
if (!cmdline) {
efi_err("getting command line via LOADED_IMAGE_PROTOCOL\n");
return EFI_OUT_OF_RESOURCES;
}
if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) ||
IS_ENABLED(CONFIG_CMDLINE_FORCE) ||
cmdline_size == 0) {
status = efi_parse_options(CONFIG_CMDLINE);
if (status != EFI_SUCCESS) {
efi_err("Failed to parse options\n");
goto fail_free_cmdline;
}
}
if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && cmdline_size > 0) {
status = efi_parse_options(cmdline);
if (status != EFI_SUCCESS) {
efi_err("Failed to parse options\n");
goto fail_free_cmdline;
}
}
*cmdline_ptr = cmdline;
return EFI_SUCCESS;
fail_free_cmdline:
efi_bs_call(free_pool, cmdline_ptr);
return status;
}
efi_status_t efi_stub_common(efi_handle_t handle,
efi_loaded_image_t *image,
unsigned long image_addr,
char *cmdline_ptr)
{
struct screen_info *si;
efi_status_t status;
status = check_platform_features();
if (status != EFI_SUCCESS)
return status;
si = setup_graphics();
efi_retrieve_tpm2_eventlog();
/* Ask the firmware to clear memory on unclean shutdown */
efi_enable_reset_attack_mitigation();
efi_load_initrd(image, ULONG_MAX, efi_get_max_initrd_addr(image_addr),
NULL);
efi_random_get_seed();
/* force efi_novamap if SetVirtualAddressMap() is unsupported */
efi_novamap |= !(get_supported_rt_services() &
EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP);
install_memreserve_table();
status = efi_boot_kernel(handle, image, image_addr, cmdline_ptr);
free_screen_info(si);
return status;
}
/*
* efi_allocate_virtmap() - create a pool allocation for the virtmap
*
* Create an allocation that is of sufficient size to hold all the memory
* descriptors that will be passed to SetVirtualAddressMap() to inform the
* firmware about the virtual mapping that will be used under the OS to call
* into the firmware.
*/
efi_status_t efi_alloc_virtmap(efi_memory_desc_t **virtmap,
unsigned long *desc_size, u32 *desc_ver)
{
unsigned long size, mmap_key;
efi_status_t status;
/*
* Use the size of the current memory map as an upper bound for the
* size of the buffer we need to pass to SetVirtualAddressMap() to
* cover all EFI_MEMORY_RUNTIME regions.
*/
size = 0;
status = efi_bs_call(get_memory_map, &size, NULL, &mmap_key, desc_size,
desc_ver);
if (status != EFI_BUFFER_TOO_SMALL)
return EFI_LOAD_ERROR;
return efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
(void **)virtmap);
}
/*
* efi_get_virtmap() - create a virtual mapping for the EFI memory map
*
* This function populates the virt_addr fields of all memory region descriptors
* in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors
* are also copied to @runtime_map, and their total count is returned in @count.
*/
void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
unsigned long desc_size, efi_memory_desc_t *runtime_map,
int *count)
{
u64 efi_virt_base = virtmap_base;
efi_memory_desc_t *in, *out = runtime_map;
int l;
*count = 0;
for (l = 0; l < map_size; l += desc_size) {
u64 paddr, size;
in = (void *)memory_map + l;
if (!(in->attribute & EFI_MEMORY_RUNTIME))
continue;
paddr = in->phys_addr;
size = in->num_pages * EFI_PAGE_SIZE;
in->virt_addr = in->phys_addr + EFI_RT_VIRTUAL_OFFSET;
if (efi_novamap) {
continue;
}
/*
* Make the mapping compatible with 64k pages: this allows
* a 4k page size kernel to kexec a 64k page size kernel and
* vice versa.
*/
if (!flat_va_mapping) {
paddr = round_down(in->phys_addr, SZ_64K);
size += in->phys_addr - paddr;
/*
* Avoid wasting memory on PTEs by choosing a virtual
* base that is compatible with section mappings if this
* region has the appropriate size and physical
* alignment. (Sections are 2 MB on 4k granule kernels)
*/
if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M)
efi_virt_base = round_up(efi_virt_base, SZ_2M);
else
efi_virt_base = round_up(efi_virt_base, SZ_64K);
in->virt_addr += efi_virt_base - paddr;
efi_virt_base += size;
}
memcpy(out, in, desc_size);
out = (void *)out + desc_size;
++*count;
}
}