diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/firmware/efi/libstub/fdt.c | 379 |
1 files changed, 379 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c new file mode 100644 index 000000000..70e9789ff --- /dev/null +++ b/drivers/firmware/efi/libstub/fdt.c @@ -0,0 +1,379 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * FDT related Helper functions used by the EFI stub on multiple + * architectures. This should be #included by the EFI stub + * implementation files. + * + * Copyright 2013 Linaro Limited; author Roy Franz + */ + +#include <linux/efi.h> +#include <linux/libfdt.h> +#include <asm/efi.h> + +#include "efistub.h" + +#define EFI_DT_ADDR_CELLS_DEFAULT 2 +#define EFI_DT_SIZE_CELLS_DEFAULT 2 + +static void fdt_update_cell_size(void *fdt) +{ + int offset; + + offset = fdt_path_offset(fdt, "/"); + /* Set the #address-cells and #size-cells values for an empty tree */ + + fdt_setprop_u32(fdt, offset, "#address-cells", EFI_DT_ADDR_CELLS_DEFAULT); + fdt_setprop_u32(fdt, offset, "#size-cells", EFI_DT_SIZE_CELLS_DEFAULT); +} + +static efi_status_t update_fdt(void *orig_fdt, unsigned long orig_fdt_size, + void *fdt, int new_fdt_size, char *cmdline_ptr) +{ + int node, num_rsv; + int status; + u32 fdt_val32; + u64 fdt_val64; + + /* Do some checks on provided FDT, if it exists: */ + if (orig_fdt) { + if (fdt_check_header(orig_fdt)) { + efi_err("Device Tree header not valid!\n"); + return EFI_LOAD_ERROR; + } + /* + * We don't get the size of the FDT if we get if from a + * configuration table: + */ + if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) { + efi_err("Truncated device tree! foo!\n"); + return EFI_LOAD_ERROR; + } + } + + if (orig_fdt) { + status = fdt_open_into(orig_fdt, fdt, new_fdt_size); + } else { + status = fdt_create_empty_tree(fdt, new_fdt_size); + if (status == 0) { + /* + * Any failure from the following function is + * non-critical: + */ + fdt_update_cell_size(fdt); + } + } + + if (status != 0) + goto fdt_set_fail; + + /* + * Delete all memory reserve map entries. When booting via UEFI, + * kernel will use the UEFI memory map to find reserved regions. + */ + num_rsv = fdt_num_mem_rsv(fdt); + while (num_rsv-- > 0) + fdt_del_mem_rsv(fdt, num_rsv); + + node = fdt_subnode_offset(fdt, 0, "chosen"); + if (node < 0) { + node = fdt_add_subnode(fdt, 0, "chosen"); + if (node < 0) { + /* 'node' is an error code when negative: */ + status = node; + goto fdt_set_fail; + } + } + + if (cmdline_ptr != NULL && strlen(cmdline_ptr) > 0) { + status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr, + strlen(cmdline_ptr) + 1); + if (status) + goto fdt_set_fail; + } + + /* Add FDT entries for EFI runtime services in chosen node. */ + node = fdt_subnode_offset(fdt, 0, "chosen"); + fdt_val64 = cpu_to_fdt64((u64)(unsigned long)efi_system_table); + + status = fdt_setprop_var(fdt, node, "linux,uefi-system-table", fdt_val64); + if (status) + goto fdt_set_fail; + + fdt_val64 = U64_MAX; /* placeholder */ + + status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-start", fdt_val64); + if (status) + goto fdt_set_fail; + + fdt_val32 = U32_MAX; /* placeholder */ + + status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-size", fdt_val32); + if (status) + goto fdt_set_fail; + + status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32); + if (status) + goto fdt_set_fail; + + status = fdt_setprop_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32); + if (status) + goto fdt_set_fail; + + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && !efi_nokaslr) { + efi_status_t efi_status; + + efi_status = efi_get_random_bytes(sizeof(fdt_val64), + (u8 *)&fdt_val64); + if (efi_status == EFI_SUCCESS) { + status = fdt_setprop_var(fdt, node, "kaslr-seed", fdt_val64); + if (status) + goto fdt_set_fail; + } + } + + /* Shrink the FDT back to its minimum size: */ + fdt_pack(fdt); + + return EFI_SUCCESS; + +fdt_set_fail: + if (status == -FDT_ERR_NOSPACE) + return EFI_BUFFER_TOO_SMALL; + + return EFI_LOAD_ERROR; +} + +static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map) +{ + int node = fdt_path_offset(fdt, "/chosen"); + u64 fdt_val64; + u32 fdt_val32; + int err; + + if (node < 0) + return EFI_LOAD_ERROR; + + fdt_val64 = cpu_to_fdt64((unsigned long)map->map); + + err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-start", fdt_val64); + if (err) + return EFI_LOAD_ERROR; + + fdt_val32 = cpu_to_fdt32(map->map_size); + + err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-size", fdt_val32); + if (err) + return EFI_LOAD_ERROR; + + fdt_val32 = cpu_to_fdt32(map->desc_size); + + err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-size", fdt_val32); + if (err) + return EFI_LOAD_ERROR; + + fdt_val32 = cpu_to_fdt32(map->desc_ver); + + err = fdt_setprop_inplace_var(fdt, node, "linux,uefi-mmap-desc-ver", fdt_val32); + if (err) + return EFI_LOAD_ERROR; + + return EFI_SUCCESS; +} + +struct exit_boot_struct { + struct efi_boot_memmap *boot_memmap; + efi_memory_desc_t *runtime_map; + int runtime_entry_count; + void *new_fdt_addr; +}; + +static efi_status_t exit_boot_func(struct efi_boot_memmap *map, void *priv) +{ + struct exit_boot_struct *p = priv; + + p->boot_memmap = map; + + /* + * Update the memory map with virtual addresses. The function will also + * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME + * entries so that we can pass it straight to SetVirtualAddressMap() + */ + efi_get_virtmap(map->map, map->map_size, map->desc_size, + p->runtime_map, &p->runtime_entry_count); + + return update_fdt_memmap(p->new_fdt_addr, map); +} + +#ifndef MAX_FDT_SIZE +# define MAX_FDT_SIZE SZ_2M +#endif + +/* + * Allocate memory for a new FDT, then add EFI and commandline related fields + * to the FDT. This routine increases the FDT allocation size until the + * allocated memory is large enough. EFI allocations are in EFI_PAGE_SIZE + * granules, which are fixed at 4K bytes, so in most cases the first allocation + * should succeed. EFI boot services are exited at the end of this function. + * There must be no allocations between the get_memory_map() call and the + * exit_boot_services() call, so the exiting of boot services is very tightly + * tied to the creation of the FDT with the final memory map in it. + */ +static +efi_status_t allocate_new_fdt_and_exit_boot(void *handle, + efi_loaded_image_t *image, + unsigned long *new_fdt_addr, + char *cmdline_ptr) +{ + unsigned long desc_size; + u32 desc_ver; + efi_status_t status; + struct exit_boot_struct priv; + unsigned long fdt_addr = 0; + unsigned long fdt_size = 0; + + if (!efi_novamap) { + status = efi_alloc_virtmap(&priv.runtime_map, &desc_size, + &desc_ver); + if (status != EFI_SUCCESS) { + efi_err("Unable to retrieve UEFI memory map.\n"); + return status; + } + } + + /* + * Unauthenticated device tree data is a security hazard, so ignore + * 'dtb=' unless UEFI Secure Boot is disabled. We assume that secure + * boot is enabled if we can't determine its state. + */ + if (!IS_ENABLED(CONFIG_EFI_ARMSTUB_DTB_LOADER) || + efi_get_secureboot() != efi_secureboot_mode_disabled) { + if (strstr(cmdline_ptr, "dtb=")) + efi_err("Ignoring DTB from command line.\n"); + } else { + status = efi_load_dtb(image, &fdt_addr, &fdt_size); + + if (status != EFI_SUCCESS && status != EFI_NOT_READY) { + efi_err("Failed to load device tree!\n"); + goto fail; + } + } + + if (fdt_addr) { + efi_info("Using DTB from command line\n"); + } else { + /* Look for a device tree configuration table entry. */ + fdt_addr = (uintptr_t)get_fdt(&fdt_size); + if (fdt_addr) + efi_info("Using DTB from configuration table\n"); + } + + if (!fdt_addr) + efi_info("Generating empty DTB\n"); + + efi_info("Exiting boot services...\n"); + + status = efi_allocate_pages(MAX_FDT_SIZE, new_fdt_addr, ULONG_MAX); + if (status != EFI_SUCCESS) { + efi_err("Unable to allocate memory for new device tree.\n"); + goto fail; + } + + status = update_fdt((void *)fdt_addr, fdt_size, + (void *)*new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr); + + if (status != EFI_SUCCESS) { + efi_err("Unable to construct new device tree.\n"); + goto fail_free_new_fdt; + } + + priv.new_fdt_addr = (void *)*new_fdt_addr; + + status = efi_exit_boot_services(handle, &priv, exit_boot_func); + + if (status == EFI_SUCCESS) { + efi_set_virtual_address_map_t *svam; + + if (efi_novamap) + return EFI_SUCCESS; + + /* Install the new virtual address map */ + svam = efi_system_table->runtime->set_virtual_address_map; + status = svam(priv.runtime_entry_count * desc_size, desc_size, + desc_ver, priv.runtime_map); + + /* + * We are beyond the point of no return here, so if the call to + * SetVirtualAddressMap() failed, we need to signal that to the + * incoming kernel but proceed normally otherwise. + */ + if (status != EFI_SUCCESS) { + efi_memory_desc_t *p; + int l; + + /* + * Set the virtual address field of all + * EFI_MEMORY_RUNTIME entries to U64_MAX. This will + * signal the incoming kernel that no virtual + * translation has been installed. + */ + for (l = 0; l < priv.boot_memmap->map_size; + l += priv.boot_memmap->desc_size) { + p = (void *)priv.boot_memmap->map + l; + + if (p->attribute & EFI_MEMORY_RUNTIME) + p->virt_addr = U64_MAX; + } + } + return EFI_SUCCESS; + } + + efi_err("Exit boot services failed.\n"); + +fail_free_new_fdt: + efi_free(MAX_FDT_SIZE, *new_fdt_addr); + +fail: + efi_free(fdt_size, fdt_addr); + + efi_bs_call(free_pool, priv.runtime_map); + + return EFI_LOAD_ERROR; +} + +efi_status_t efi_boot_kernel(void *handle, efi_loaded_image_t *image, + unsigned long kernel_addr, char *cmdline_ptr) +{ + unsigned long fdt_addr; + efi_status_t status; + + status = allocate_new_fdt_and_exit_boot(handle, image, &fdt_addr, + cmdline_ptr); + if (status != EFI_SUCCESS) { + efi_err("Failed to update FDT and exit boot services\n"); + return status; + } + + if (IS_ENABLED(CONFIG_ARM)) + efi_handle_post_ebs_state(); + + efi_enter_kernel(kernel_addr, fdt_addr, fdt_totalsize((void *)fdt_addr)); + /* not reached */ +} + +void *get_fdt(unsigned long *fdt_size) +{ + void *fdt; + + fdt = get_efi_config_table(DEVICE_TREE_GUID); + + if (!fdt) + return NULL; + + if (fdt_check_header(fdt) != 0) { + efi_err("Invalid header detected on UEFI supplied FDT, ignoring ...\n"); + return NULL; + } + *fdt_size = fdt_totalsize(fdt); + return fdt; +} |