480 lines
13 KiB
C
480 lines
13 KiB
C
/*
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* EFI stub implementation that is shared by arm and arm64 architectures.
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* This should be #included by the EFI stub implementation files.
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*
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* Copyright (C) 2013,2014 Linaro Limited
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* Roy Franz <roy.franz@linaro.org
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* Copyright (C) 2013 Red Hat, Inc.
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* Mark Salter <msalter@redhat.com>
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*
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* This file is part of the Linux kernel, and is made available under the
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* terms of the GNU General Public License version 2.
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*
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*/
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#include <linux/efi.h>
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#include <linux/sort.h>
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#include <asm/efi.h>
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#include "efistub.h"
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static int efi_get_secureboot(efi_system_table_t *sys_table_arg)
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{
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static efi_char16_t const sb_var_name[] = {
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'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0 };
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static efi_char16_t const sm_var_name[] = {
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'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0 };
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efi_guid_t var_guid = EFI_GLOBAL_VARIABLE_GUID;
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efi_get_variable_t *f_getvar = sys_table_arg->runtime->get_variable;
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u8 val;
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unsigned long size = sizeof(val);
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efi_status_t status;
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status = f_getvar((efi_char16_t *)sb_var_name, (efi_guid_t *)&var_guid,
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NULL, &size, &val);
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if (status != EFI_SUCCESS)
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goto out_efi_err;
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if (val == 0)
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return 0;
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status = f_getvar((efi_char16_t *)sm_var_name, (efi_guid_t *)&var_guid,
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NULL, &size, &val);
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if (status != EFI_SUCCESS)
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goto out_efi_err;
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if (val == 1)
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return 0;
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return 1;
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out_efi_err:
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switch (status) {
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case EFI_NOT_FOUND:
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return 0;
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case EFI_DEVICE_ERROR:
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return -EIO;
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case EFI_SECURITY_VIOLATION:
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return -EACCES;
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default:
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return -EINVAL;
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}
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}
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efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
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void *__image, void **__fh)
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{
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efi_file_io_interface_t *io;
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efi_loaded_image_t *image = __image;
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efi_file_handle_t *fh;
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efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
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efi_status_t status;
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void *handle = (void *)(unsigned long)image->device_handle;
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status = sys_table_arg->boottime->handle_protocol(handle,
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&fs_proto, (void **)&io);
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if (status != EFI_SUCCESS) {
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efi_printk(sys_table_arg, "Failed to handle fs_proto\n");
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return status;
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}
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status = io->open_volume(io, &fh);
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if (status != EFI_SUCCESS)
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efi_printk(sys_table_arg, "Failed to open volume\n");
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*__fh = fh;
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return status;
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}
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efi_status_t efi_file_close(void *handle)
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{
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efi_file_handle_t *fh = handle;
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return fh->close(handle);
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}
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efi_status_t
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efi_file_read(void *handle, unsigned long *size, void *addr)
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{
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efi_file_handle_t *fh = handle;
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return fh->read(handle, size, addr);
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}
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efi_status_t
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efi_file_size(efi_system_table_t *sys_table_arg, void *__fh,
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efi_char16_t *filename_16, void **handle, u64 *file_sz)
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{
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efi_file_handle_t *h, *fh = __fh;
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efi_file_info_t *info;
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efi_status_t status;
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efi_guid_t info_guid = EFI_FILE_INFO_ID;
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unsigned long info_sz;
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status = fh->open(fh, &h, filename_16, EFI_FILE_MODE_READ, (u64)0);
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if (status != EFI_SUCCESS) {
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efi_printk(sys_table_arg, "Failed to open file: ");
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efi_char16_printk(sys_table_arg, filename_16);
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efi_printk(sys_table_arg, "\n");
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return status;
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}
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*handle = h;
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info_sz = 0;
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status = h->get_info(h, &info_guid, &info_sz, NULL);
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if (status != EFI_BUFFER_TOO_SMALL) {
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efi_printk(sys_table_arg, "Failed to get file info size\n");
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return status;
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}
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grow:
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status = sys_table_arg->boottime->allocate_pool(EFI_LOADER_DATA,
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info_sz, (void **)&info);
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if (status != EFI_SUCCESS) {
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efi_printk(sys_table_arg, "Failed to alloc mem for file info\n");
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return status;
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}
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status = h->get_info(h, &info_guid, &info_sz,
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info);
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if (status == EFI_BUFFER_TOO_SMALL) {
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sys_table_arg->boottime->free_pool(info);
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goto grow;
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}
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*file_sz = info->file_size;
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sys_table_arg->boottime->free_pool(info);
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if (status != EFI_SUCCESS)
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efi_printk(sys_table_arg, "Failed to get initrd info\n");
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return status;
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}
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void efi_char16_printk(efi_system_table_t *sys_table_arg,
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efi_char16_t *str)
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{
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struct efi_simple_text_output_protocol *out;
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out = (struct efi_simple_text_output_protocol *)sys_table_arg->con_out;
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out->output_string(out, str);
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}
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static struct screen_info *setup_graphics(efi_system_table_t *sys_table_arg)
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{
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efi_guid_t gop_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
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efi_status_t status;
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unsigned long size;
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void **gop_handle = NULL;
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struct screen_info *si = NULL;
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size = 0;
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status = efi_call_early(locate_handle, EFI_LOCATE_BY_PROTOCOL,
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&gop_proto, NULL, &size, gop_handle);
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if (status == EFI_BUFFER_TOO_SMALL) {
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si = alloc_screen_info(sys_table_arg);
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if (!si)
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return NULL;
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efi_setup_gop(sys_table_arg, si, &gop_proto, size);
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}
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return si;
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}
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/*
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* This function handles the architcture specific differences between arm and
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* arm64 regarding where the kernel image must be loaded and any memory that
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* must be reserved. On failure it is required to free all
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* all allocations it has made.
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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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* EFI entry point for the arm/arm64 EFI stubs. This is the entrypoint
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* that is described in the PE/COFF header. Most of the code is the same
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* for both archictectures, with the arch-specific code provided in the
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* handle_kernel_image() function.
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*/
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unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
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unsigned long *image_addr)
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{
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efi_loaded_image_t *image;
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efi_status_t status;
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unsigned long image_size = 0;
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unsigned long dram_base;
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/* addr/point and size pairs for memory management*/
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unsigned long initrd_addr;
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u64 initrd_size = 0;
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unsigned long fdt_addr = 0; /* Original DTB */
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unsigned long fdt_size = 0;
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char *cmdline_ptr = NULL;
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int cmdline_size = 0;
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unsigned long new_fdt_addr;
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efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
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unsigned long reserve_addr = 0;
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unsigned long reserve_size = 0;
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int secure_boot = 0;
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struct screen_info *si;
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/* Check if we were booted by the EFI firmware */
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if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
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goto fail;
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pr_efi(sys_table, "Booting Linux Kernel...\n");
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status = check_platform_features(sys_table);
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if (status != EFI_SUCCESS)
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goto fail;
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/*
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* Get a handle to the loaded image protocol. This is used to get
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* information about the running image, such as size and the command
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* line.
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*/
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status = sys_table->boottime->handle_protocol(handle,
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&loaded_image_proto, (void *)&image);
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if (status != EFI_SUCCESS) {
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pr_efi_err(sys_table, "Failed to get loaded image protocol\n");
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goto fail;
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}
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dram_base = get_dram_base(sys_table);
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if (dram_base == EFI_ERROR) {
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pr_efi_err(sys_table, "Failed to find DRAM base\n");
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goto fail;
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}
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/*
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* Get the command line from EFI, using the LOADED_IMAGE
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* protocol. We are going to copy the command line into the
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* device tree, so this can be allocated anywhere.
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*/
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cmdline_ptr = efi_convert_cmdline(sys_table, image, &cmdline_size);
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if (!cmdline_ptr) {
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pr_efi_err(sys_table, "getting command line via LOADED_IMAGE_PROTOCOL\n");
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goto fail;
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}
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si = setup_graphics(sys_table);
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status = handle_kernel_image(sys_table, image_addr, &image_size,
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&reserve_addr,
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&reserve_size,
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dram_base, image);
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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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goto fail_free_cmdline;
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}
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if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) ||
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IS_ENABLED(CONFIG_CMDLINE_FORCE) ||
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cmdline_size == 0)
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efi_parse_options(CONFIG_CMDLINE);
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if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && cmdline_size > 0)
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efi_parse_options(cmdline_ptr);
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secure_boot = efi_get_secureboot(sys_table);
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if (secure_boot > 0)
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pr_efi(sys_table, "UEFI Secure Boot is enabled.\n");
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if (secure_boot < 0) {
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pr_efi_err(sys_table,
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"could not determine UEFI Secure Boot status.\n");
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}
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/*
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* Unauthenticated device tree data is a security hazard, so
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* ignore 'dtb=' unless UEFI Secure Boot is disabled.
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*/
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if (secure_boot != 0 && strstr(cmdline_ptr, "dtb=")) {
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pr_efi(sys_table, "Ignoring DTB from command line.\n");
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} else {
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status = handle_cmdline_files(sys_table, image, cmdline_ptr,
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"dtb=",
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~0UL, &fdt_addr, &fdt_size);
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if (status != EFI_SUCCESS) {
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pr_efi_err(sys_table, "Failed to load device tree!\n");
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goto fail_free_image;
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}
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}
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if (fdt_addr) {
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pr_efi(sys_table, "Using DTB from command line\n");
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} else {
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/* Look for a device tree configuration table entry. */
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fdt_addr = (uintptr_t)get_fdt(sys_table, &fdt_size);
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if (fdt_addr)
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pr_efi(sys_table, "Using DTB from configuration table\n");
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}
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if (!fdt_addr)
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pr_efi(sys_table, "Generating empty DTB\n");
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status = handle_cmdline_files(sys_table, image, cmdline_ptr,
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"initrd=", dram_base + SZ_512M,
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(unsigned long *)&initrd_addr,
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(unsigned long *)&initrd_size);
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if (status != EFI_SUCCESS)
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pr_efi_err(sys_table, "Failed initrd from command line!\n");
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new_fdt_addr = fdt_addr;
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status = allocate_new_fdt_and_exit_boot(sys_table, handle,
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&new_fdt_addr, dram_base + MAX_FDT_OFFSET,
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initrd_addr, initrd_size, cmdline_ptr,
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fdt_addr, fdt_size);
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/*
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* If all went well, we need to return the FDT address to the
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* calling function so it can be passed to kernel as part of
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* the kernel boot protocol.
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*/
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if (status == EFI_SUCCESS)
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return new_fdt_addr;
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pr_efi_err(sys_table, "Failed to update FDT and exit boot services\n");
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efi_free(sys_table, initrd_size, initrd_addr);
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efi_free(sys_table, fdt_size, fdt_addr);
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fail_free_image:
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efi_free(sys_table, image_size, *image_addr);
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efi_free(sys_table, reserve_size, reserve_addr);
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fail_free_cmdline:
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free_screen_info(sys_table, si);
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efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr);
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fail:
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return EFI_ERROR;
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}
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/*
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* This is the base address at which to start allocating virtual memory ranges
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* for UEFI Runtime Services. This is in the low TTBR0 range so that we can use
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* any allocation we choose, and eliminate the risk of a conflict after kexec.
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* The value chosen is the largest non-zero power of 2 suitable for this purpose
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* both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can
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* be mapped efficiently.
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* Since 32-bit ARM could potentially execute with a 1G/3G user/kernel split,
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* map everything below 1 GB.
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*/
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#define EFI_RT_VIRTUAL_BASE SZ_512M
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static int cmp_mem_desc(const void *l, const void *r)
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{
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const efi_memory_desc_t *left = l, *right = r;
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return (left->phys_addr > right->phys_addr) ? 1 : -1;
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}
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/*
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* Returns whether region @left ends exactly where region @right starts,
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* or false if either argument is NULL.
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*/
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static bool regions_are_adjacent(efi_memory_desc_t *left,
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efi_memory_desc_t *right)
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{
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u64 left_end;
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if (left == NULL || right == NULL)
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return false;
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left_end = left->phys_addr + left->num_pages * EFI_PAGE_SIZE;
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return left_end == right->phys_addr;
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}
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/*
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* Returns whether region @left and region @right have compatible memory type
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* mapping attributes, and are both EFI_MEMORY_RUNTIME regions.
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*/
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static bool regions_have_compatible_memory_type_attrs(efi_memory_desc_t *left,
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efi_memory_desc_t *right)
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{
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static const u64 mem_type_mask = EFI_MEMORY_WB | EFI_MEMORY_WT |
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EFI_MEMORY_WC | EFI_MEMORY_UC |
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EFI_MEMORY_RUNTIME;
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return ((left->attribute ^ right->attribute) & mem_type_mask) == 0;
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}
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/*
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* efi_get_virtmap() - create a virtual mapping for the EFI memory map
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*
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* This function populates the virt_addr fields of all memory region descriptors
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* in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors
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* are also copied to @runtime_map, and their total count is returned in @count.
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*/
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void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
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unsigned long desc_size, efi_memory_desc_t *runtime_map,
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int *count)
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{
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u64 efi_virt_base = EFI_RT_VIRTUAL_BASE;
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efi_memory_desc_t *in, *prev = NULL, *out = runtime_map;
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int l;
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/*
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* To work around potential issues with the Properties Table feature
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* introduced in UEFI 2.5, which may split PE/COFF executable images
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* in memory into several RuntimeServicesCode and RuntimeServicesData
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* regions, we need to preserve the relative offsets between adjacent
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* EFI_MEMORY_RUNTIME regions with the same memory type attributes.
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* The easiest way to find adjacent regions is to sort the memory map
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* before traversing it.
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*/
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sort(memory_map, map_size / desc_size, desc_size, cmp_mem_desc, NULL);
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for (l = 0; l < map_size; l += desc_size, prev = in) {
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u64 paddr, size;
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in = (void *)memory_map + l;
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if (!(in->attribute & EFI_MEMORY_RUNTIME))
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continue;
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paddr = in->phys_addr;
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size = in->num_pages * EFI_PAGE_SIZE;
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/*
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* Make the mapping compatible with 64k pages: this allows
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* a 4k page size kernel to kexec a 64k page size kernel and
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* vice versa.
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*/
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if (!regions_are_adjacent(prev, in) ||
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!regions_have_compatible_memory_type_attrs(prev, in)) {
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paddr = round_down(in->phys_addr, SZ_64K);
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size += in->phys_addr - paddr;
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/*
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* Avoid wasting memory on PTEs by choosing a virtual
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* base that is compatible with section mappings if this
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* region has the appropriate size and physical
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* alignment. (Sections are 2 MB on 4k granule kernels)
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*/
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if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M)
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efi_virt_base = round_up(efi_virt_base, SZ_2M);
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else
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efi_virt_base = round_up(efi_virt_base, SZ_64K);
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}
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in->virt_addr = efi_virt_base + in->phys_addr - paddr;
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efi_virt_base += size;
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memcpy(out, in, desc_size);
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out = (void *)out + desc_size;
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++*count;
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}
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}
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