diff options
Diffstat (limited to 'drivers/firmware/efi/libstub/x86-stub.c')
| -rw-r--r-- | drivers/firmware/efi/libstub/x86-stub.c | 1003 |
1 files changed, 1003 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c new file mode 100644 index 0000000000..70b325a2f1 --- /dev/null +++ b/drivers/firmware/efi/libstub/x86-stub.c @@ -0,0 +1,1003 @@ +// SPDX-License-Identifier: GPL-2.0-only + +/* ----------------------------------------------------------------------- + * + * Copyright 2011 Intel Corporation; author Matt Fleming + * + * ----------------------------------------------------------------------- */ + +#include <linux/efi.h> +#include <linux/pci.h> +#include <linux/stddef.h> + +#include <asm/efi.h> +#include <asm/e820/types.h> +#include <asm/setup.h> +#include <asm/desc.h> +#include <asm/boot.h> +#include <asm/kaslr.h> +#include <asm/sev.h> + +#include "efistub.h" +#include "x86-stub.h" + +const efi_system_table_t *efi_system_table; +const efi_dxe_services_table_t *efi_dxe_table; +static efi_loaded_image_t *image = NULL; +static efi_memory_attribute_protocol_t *memattr; + +typedef union sev_memory_acceptance_protocol sev_memory_acceptance_protocol_t; +union sev_memory_acceptance_protocol { + struct { + efi_status_t (__efiapi * allow_unaccepted_memory)( + sev_memory_acceptance_protocol_t *); + }; + struct { + u32 allow_unaccepted_memory; + } mixed_mode; +}; + +static efi_status_t +preserve_pci_rom_image(efi_pci_io_protocol_t *pci, struct pci_setup_rom **__rom) +{ + struct pci_setup_rom *rom = NULL; + efi_status_t status; + unsigned long size; + uint64_t romsize; + void *romimage; + + /* + * Some firmware images contain EFI function pointers at the place where + * the romimage and romsize fields are supposed to be. Typically the EFI + * code is mapped at high addresses, translating to an unrealistically + * large romsize. The UEFI spec limits the size of option ROMs to 16 + * MiB so we reject any ROMs over 16 MiB in size to catch this. + */ + romimage = efi_table_attr(pci, romimage); + romsize = efi_table_attr(pci, romsize); + if (!romimage || !romsize || romsize > SZ_16M) + return EFI_INVALID_PARAMETER; + + size = romsize + sizeof(*rom); + + status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size, + (void **)&rom); + if (status != EFI_SUCCESS) { + efi_err("Failed to allocate memory for 'rom'\n"); + return status; + } + + memset(rom, 0, sizeof(*rom)); + + rom->data.type = SETUP_PCI; + rom->data.len = size - sizeof(struct setup_data); + rom->data.next = 0; + rom->pcilen = romsize; + *__rom = rom; + + status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16, + PCI_VENDOR_ID, 1, &rom->vendor); + + if (status != EFI_SUCCESS) { + efi_err("Failed to read rom->vendor\n"); + goto free_struct; + } + + status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16, + PCI_DEVICE_ID, 1, &rom->devid); + + if (status != EFI_SUCCESS) { + efi_err("Failed to read rom->devid\n"); + goto free_struct; + } + + status = efi_call_proto(pci, get_location, &rom->segment, &rom->bus, + &rom->device, &rom->function); + + if (status != EFI_SUCCESS) + goto free_struct; + + memcpy(rom->romdata, romimage, romsize); + return status; + +free_struct: + efi_bs_call(free_pool, rom); + return status; +} + +/* + * There's no way to return an informative status from this function, + * because any analysis (and printing of error messages) needs to be + * done directly at the EFI function call-site. + * + * For example, EFI_INVALID_PARAMETER could indicate a bug or maybe we + * just didn't find any PCI devices, but there's no way to tell outside + * the context of the call. + */ +static void setup_efi_pci(struct boot_params *params) +{ + efi_status_t status; + void **pci_handle = NULL; + efi_guid_t pci_proto = EFI_PCI_IO_PROTOCOL_GUID; + unsigned long size = 0; + struct setup_data *data; + efi_handle_t h; + int i; + + status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL, + &pci_proto, NULL, &size, pci_handle); + + if (status == EFI_BUFFER_TOO_SMALL) { + status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size, + (void **)&pci_handle); + + if (status != EFI_SUCCESS) { + efi_err("Failed to allocate memory for 'pci_handle'\n"); + return; + } + + status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL, + &pci_proto, NULL, &size, pci_handle); + } + + if (status != EFI_SUCCESS) + goto free_handle; + + data = (struct setup_data *)(unsigned long)params->hdr.setup_data; + + while (data && data->next) + data = (struct setup_data *)(unsigned long)data->next; + + for_each_efi_handle(h, pci_handle, size, i) { + efi_pci_io_protocol_t *pci = NULL; + struct pci_setup_rom *rom; + + status = efi_bs_call(handle_protocol, h, &pci_proto, + (void **)&pci); + if (status != EFI_SUCCESS || !pci) + continue; + + status = preserve_pci_rom_image(pci, &rom); + if (status != EFI_SUCCESS) + continue; + + if (data) + data->next = (unsigned long)rom; + else + params->hdr.setup_data = (unsigned long)rom; + + data = (struct setup_data *)rom; + } + +free_handle: + efi_bs_call(free_pool, pci_handle); +} + +static void retrieve_apple_device_properties(struct boot_params *boot_params) +{ + efi_guid_t guid = APPLE_PROPERTIES_PROTOCOL_GUID; + struct setup_data *data, *new; + efi_status_t status; + u32 size = 0; + apple_properties_protocol_t *p; + + status = efi_bs_call(locate_protocol, &guid, NULL, (void **)&p); + if (status != EFI_SUCCESS) + return; + + if (efi_table_attr(p, version) != 0x10000) { + efi_err("Unsupported properties proto version\n"); + return; + } + + efi_call_proto(p, get_all, NULL, &size); + if (!size) + return; + + do { + status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, + size + sizeof(struct setup_data), + (void **)&new); + if (status != EFI_SUCCESS) { + efi_err("Failed to allocate memory for 'properties'\n"); + return; + } + + status = efi_call_proto(p, get_all, new->data, &size); + + if (status == EFI_BUFFER_TOO_SMALL) + efi_bs_call(free_pool, new); + } while (status == EFI_BUFFER_TOO_SMALL); + + new->type = SETUP_APPLE_PROPERTIES; + new->len = size; + new->next = 0; + + data = (struct setup_data *)(unsigned long)boot_params->hdr.setup_data; + if (!data) { + boot_params->hdr.setup_data = (unsigned long)new; + } else { + while (data->next) + data = (struct setup_data *)(unsigned long)data->next; + data->next = (unsigned long)new; + } +} + +void efi_adjust_memory_range_protection(unsigned long start, + unsigned long size) +{ + efi_status_t status; + efi_gcd_memory_space_desc_t desc; + unsigned long end, next; + unsigned long rounded_start, rounded_end; + unsigned long unprotect_start, unprotect_size; + + rounded_start = rounddown(start, EFI_PAGE_SIZE); + rounded_end = roundup(start + size, EFI_PAGE_SIZE); + + if (memattr != NULL) { + efi_call_proto(memattr, clear_memory_attributes, rounded_start, + rounded_end - rounded_start, EFI_MEMORY_XP); + return; + } + + if (efi_dxe_table == NULL) + return; + + /* + * Don't modify memory region attributes, they are + * already suitable, to lower the possibility to + * encounter firmware bugs. + */ + + for (end = start + size; start < end; start = next) { + + status = efi_dxe_call(get_memory_space_descriptor, start, &desc); + + if (status != EFI_SUCCESS) + return; + + next = desc.base_address + desc.length; + + /* + * Only system memory is suitable for trampoline/kernel image placement, + * so only this type of memory needs its attributes to be modified. + */ + + if (desc.gcd_memory_type != EfiGcdMemoryTypeSystemMemory || + (desc.attributes & (EFI_MEMORY_RO | EFI_MEMORY_XP)) == 0) + continue; + + unprotect_start = max(rounded_start, (unsigned long)desc.base_address); + unprotect_size = min(rounded_end, next) - unprotect_start; + + status = efi_dxe_call(set_memory_space_attributes, + unprotect_start, unprotect_size, + EFI_MEMORY_WB); + + if (status != EFI_SUCCESS) { + efi_warn("Unable to unprotect memory range [%08lx,%08lx]: %lx\n", + unprotect_start, + unprotect_start + unprotect_size, + status); + } + } +} + +static void setup_unaccepted_memory(void) +{ + efi_guid_t mem_acceptance_proto = OVMF_SEV_MEMORY_ACCEPTANCE_PROTOCOL_GUID; + sev_memory_acceptance_protocol_t *proto; + efi_status_t status; + + if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY)) + return; + + /* + * Enable unaccepted memory before calling exit boot services in order + * for the UEFI to not accept all memory on EBS. + */ + status = efi_bs_call(locate_protocol, &mem_acceptance_proto, NULL, + (void **)&proto); + if (status != EFI_SUCCESS) + return; + + status = efi_call_proto(proto, allow_unaccepted_memory); + if (status != EFI_SUCCESS) + efi_err("Memory acceptance protocol failed\n"); +} + +static efi_char16_t *efistub_fw_vendor(void) +{ + unsigned long vendor = efi_table_attr(efi_system_table, fw_vendor); + + return (efi_char16_t *)vendor; +} + +static const efi_char16_t apple[] = L"Apple"; + +static void setup_quirks(struct boot_params *boot_params) +{ + if (IS_ENABLED(CONFIG_APPLE_PROPERTIES) && + !memcmp(efistub_fw_vendor(), apple, sizeof(apple))) + retrieve_apple_device_properties(boot_params); +} + +/* + * See if we have Universal Graphics Adapter (UGA) protocol + */ +static efi_status_t +setup_uga(struct screen_info *si, efi_guid_t *uga_proto, unsigned long size) +{ + efi_status_t status; + u32 width, height; + void **uga_handle = NULL; + efi_uga_draw_protocol_t *uga = NULL, *first_uga; + efi_handle_t handle; + int i; + + status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size, + (void **)&uga_handle); + if (status != EFI_SUCCESS) + return status; + + status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL, + uga_proto, NULL, &size, uga_handle); + if (status != EFI_SUCCESS) + goto free_handle; + + height = 0; + width = 0; + + first_uga = NULL; + for_each_efi_handle(handle, uga_handle, size, i) { + efi_guid_t pciio_proto = EFI_PCI_IO_PROTOCOL_GUID; + u32 w, h, depth, refresh; + void *pciio; + + status = efi_bs_call(handle_protocol, handle, uga_proto, + (void **)&uga); + if (status != EFI_SUCCESS) + continue; + + pciio = NULL; + efi_bs_call(handle_protocol, handle, &pciio_proto, &pciio); + + status = efi_call_proto(uga, get_mode, &w, &h, &depth, &refresh); + if (status == EFI_SUCCESS && (!first_uga || pciio)) { + width = w; + height = h; + + /* + * Once we've found a UGA supporting PCIIO, + * don't bother looking any further. + */ + if (pciio) + break; + + first_uga = uga; + } + } + + if (!width && !height) + goto free_handle; + + /* EFI framebuffer */ + si->orig_video_isVGA = VIDEO_TYPE_EFI; + + si->lfb_depth = 32; + si->lfb_width = width; + si->lfb_height = height; + + si->red_size = 8; + si->red_pos = 16; + si->green_size = 8; + si->green_pos = 8; + si->blue_size = 8; + si->blue_pos = 0; + si->rsvd_size = 8; + si->rsvd_pos = 24; + +free_handle: + efi_bs_call(free_pool, uga_handle); + + return status; +} + +static void setup_graphics(struct boot_params *boot_params) +{ + efi_guid_t graphics_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID; + struct screen_info *si; + efi_guid_t uga_proto = EFI_UGA_PROTOCOL_GUID; + efi_status_t status; + unsigned long size; + void **gop_handle = NULL; + void **uga_handle = NULL; + + si = &boot_params->screen_info; + memset(si, 0, sizeof(*si)); + + size = 0; + status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL, + &graphics_proto, NULL, &size, gop_handle); + if (status == EFI_BUFFER_TOO_SMALL) + status = efi_setup_gop(si, &graphics_proto, size); + + if (status != EFI_SUCCESS) { + size = 0; + status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL, + &uga_proto, NULL, &size, uga_handle); + if (status == EFI_BUFFER_TOO_SMALL) + setup_uga(si, &uga_proto, size); + } +} + + +static void __noreturn efi_exit(efi_handle_t handle, efi_status_t status) +{ + efi_bs_call(exit, handle, status, 0, NULL); + for(;;) + asm("hlt"); +} + +void __noreturn efi_stub_entry(efi_handle_t handle, + efi_system_table_t *sys_table_arg, + struct boot_params *boot_params); + +/* + * Because the x86 boot code expects to be passed a boot_params we + * need to create one ourselves (usually the bootloader would create + * one for us). + */ +efi_status_t __efiapi efi_pe_entry(efi_handle_t handle, + efi_system_table_t *sys_table_arg) +{ + struct boot_params *boot_params; + struct setup_header *hdr; + void *image_base; + efi_guid_t proto = LOADED_IMAGE_PROTOCOL_GUID; + int options_size = 0; + efi_status_t status; + char *cmdline_ptr; + + efi_system_table = sys_table_arg; + + /* Check if we were booted by the EFI firmware */ + if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) + efi_exit(handle, EFI_INVALID_PARAMETER); + + status = efi_bs_call(handle_protocol, handle, &proto, (void **)&image); + if (status != EFI_SUCCESS) { + efi_err("Failed to get handle for LOADED_IMAGE_PROTOCOL\n"); + efi_exit(handle, status); + } + + image_base = efi_table_attr(image, image_base); + + status = efi_allocate_pages(sizeof(struct boot_params), + (unsigned long *)&boot_params, ULONG_MAX); + if (status != EFI_SUCCESS) { + efi_err("Failed to allocate lowmem for boot params\n"); + efi_exit(handle, status); + } + + memset(boot_params, 0x0, sizeof(struct boot_params)); + + hdr = &boot_params->hdr; + + /* Copy the setup header from the second sector to boot_params */ + memcpy(&hdr->jump, image_base + 512, + sizeof(struct setup_header) - offsetof(struct setup_header, jump)); + + /* + * Fill out some of the header fields ourselves because the + * EFI firmware loader doesn't load the first sector. + */ + hdr->root_flags = 1; + hdr->vid_mode = 0xffff; + hdr->boot_flag = 0xAA55; + + hdr->type_of_loader = 0x21; + + /* Convert unicode cmdline to ascii */ + cmdline_ptr = efi_convert_cmdline(image, &options_size); + if (!cmdline_ptr) + goto fail; + + efi_set_u64_split((unsigned long)cmdline_ptr, + &hdr->cmd_line_ptr, &boot_params->ext_cmd_line_ptr); + + hdr->ramdisk_image = 0; + hdr->ramdisk_size = 0; + + /* + * Disregard any setup data that was provided by the bootloader: + * setup_data could be pointing anywhere, and we have no way of + * authenticating or validating the payload. + */ + hdr->setup_data = 0; + + efi_stub_entry(handle, sys_table_arg, boot_params); + /* not reached */ + +fail: + efi_free(sizeof(struct boot_params), (unsigned long)boot_params); + + efi_exit(handle, status); +} + +static void add_e820ext(struct boot_params *params, + struct setup_data *e820ext, u32 nr_entries) +{ + struct setup_data *data; + + e820ext->type = SETUP_E820_EXT; + e820ext->len = nr_entries * sizeof(struct boot_e820_entry); + e820ext->next = 0; + + data = (struct setup_data *)(unsigned long)params->hdr.setup_data; + + while (data && data->next) + data = (struct setup_data *)(unsigned long)data->next; + + if (data) + data->next = (unsigned long)e820ext; + else + params->hdr.setup_data = (unsigned long)e820ext; +} + +static efi_status_t +setup_e820(struct boot_params *params, struct setup_data *e820ext, u32 e820ext_size) +{ + struct boot_e820_entry *entry = params->e820_table; + struct efi_info *efi = ¶ms->efi_info; + struct boot_e820_entry *prev = NULL; + u32 nr_entries; + u32 nr_desc; + int i; + + nr_entries = 0; + nr_desc = efi->efi_memmap_size / efi->efi_memdesc_size; + + for (i = 0; i < nr_desc; i++) { + efi_memory_desc_t *d; + unsigned int e820_type = 0; + unsigned long m = efi->efi_memmap; + +#ifdef CONFIG_X86_64 + m |= (u64)efi->efi_memmap_hi << 32; +#endif + + d = efi_early_memdesc_ptr(m, efi->efi_memdesc_size, i); + switch (d->type) { + case EFI_RESERVED_TYPE: + case EFI_RUNTIME_SERVICES_CODE: + case EFI_RUNTIME_SERVICES_DATA: + case EFI_MEMORY_MAPPED_IO: + case EFI_MEMORY_MAPPED_IO_PORT_SPACE: + case EFI_PAL_CODE: + e820_type = E820_TYPE_RESERVED; + break; + + case EFI_UNUSABLE_MEMORY: + e820_type = E820_TYPE_UNUSABLE; + break; + + case EFI_ACPI_RECLAIM_MEMORY: + e820_type = E820_TYPE_ACPI; + break; + + case EFI_LOADER_CODE: + case EFI_LOADER_DATA: + case EFI_BOOT_SERVICES_CODE: + case EFI_BOOT_SERVICES_DATA: + case EFI_CONVENTIONAL_MEMORY: + if (efi_soft_reserve_enabled() && + (d->attribute & EFI_MEMORY_SP)) + e820_type = E820_TYPE_SOFT_RESERVED; + else + e820_type = E820_TYPE_RAM; + break; + + case EFI_ACPI_MEMORY_NVS: + e820_type = E820_TYPE_NVS; + break; + + case EFI_PERSISTENT_MEMORY: + e820_type = E820_TYPE_PMEM; + break; + + case EFI_UNACCEPTED_MEMORY: + if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY)) + continue; + e820_type = E820_TYPE_RAM; + process_unaccepted_memory(d->phys_addr, + d->phys_addr + PAGE_SIZE * d->num_pages); + break; + default: + continue; + } + + /* Merge adjacent mappings */ + if (prev && prev->type == e820_type && + (prev->addr + prev->size) == d->phys_addr) { + prev->size += d->num_pages << 12; + continue; + } + + if (nr_entries == ARRAY_SIZE(params->e820_table)) { + u32 need = (nr_desc - i) * sizeof(struct e820_entry) + + sizeof(struct setup_data); + + if (!e820ext || e820ext_size < need) + return EFI_BUFFER_TOO_SMALL; + + /* boot_params map full, switch to e820 extended */ + entry = (struct boot_e820_entry *)e820ext->data; + } + + entry->addr = d->phys_addr; + entry->size = d->num_pages << PAGE_SHIFT; + entry->type = e820_type; + prev = entry++; + nr_entries++; + } + + if (nr_entries > ARRAY_SIZE(params->e820_table)) { + u32 nr_e820ext = nr_entries - ARRAY_SIZE(params->e820_table); + + add_e820ext(params, e820ext, nr_e820ext); + nr_entries -= nr_e820ext; + } + + params->e820_entries = (u8)nr_entries; + + return EFI_SUCCESS; +} + +static efi_status_t alloc_e820ext(u32 nr_desc, struct setup_data **e820ext, + u32 *e820ext_size) +{ + efi_status_t status; + unsigned long size; + + size = sizeof(struct setup_data) + + sizeof(struct e820_entry) * nr_desc; + + if (*e820ext) { + efi_bs_call(free_pool, *e820ext); + *e820ext = NULL; + *e820ext_size = 0; + } + + status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size, + (void **)e820ext); + if (status == EFI_SUCCESS) + *e820ext_size = size; + + return status; +} + +static efi_status_t allocate_e820(struct boot_params *params, + struct setup_data **e820ext, + u32 *e820ext_size) +{ + struct efi_boot_memmap *map; + efi_status_t status; + __u32 nr_desc; + + status = efi_get_memory_map(&map, false); + if (status != EFI_SUCCESS) + return status; + + nr_desc = map->map_size / map->desc_size; + if (nr_desc > ARRAY_SIZE(params->e820_table) - EFI_MMAP_NR_SLACK_SLOTS) { + u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table) + + EFI_MMAP_NR_SLACK_SLOTS; + + status = alloc_e820ext(nr_e820ext, e820ext, e820ext_size); + } + + if (IS_ENABLED(CONFIG_UNACCEPTED_MEMORY) && status == EFI_SUCCESS) + status = allocate_unaccepted_bitmap(nr_desc, map); + + efi_bs_call(free_pool, map); + return status; +} + +struct exit_boot_struct { + struct boot_params *boot_params; + struct efi_info *efi; +}; + +static efi_status_t exit_boot_func(struct efi_boot_memmap *map, + void *priv) +{ + const char *signature; + struct exit_boot_struct *p = priv; + + signature = efi_is_64bit() ? EFI64_LOADER_SIGNATURE + : EFI32_LOADER_SIGNATURE; + memcpy(&p->efi->efi_loader_signature, signature, sizeof(__u32)); + + efi_set_u64_split((unsigned long)efi_system_table, + &p->efi->efi_systab, &p->efi->efi_systab_hi); + p->efi->efi_memdesc_size = map->desc_size; + p->efi->efi_memdesc_version = map->desc_ver; + efi_set_u64_split((unsigned long)map->map, + &p->efi->efi_memmap, &p->efi->efi_memmap_hi); + p->efi->efi_memmap_size = map->map_size; + + return EFI_SUCCESS; +} + +static efi_status_t exit_boot(struct boot_params *boot_params, void *handle) +{ + struct setup_data *e820ext = NULL; + __u32 e820ext_size = 0; + efi_status_t status; + struct exit_boot_struct priv; + + priv.boot_params = boot_params; + priv.efi = &boot_params->efi_info; + + status = allocate_e820(boot_params, &e820ext, &e820ext_size); + if (status != EFI_SUCCESS) + return status; + + /* Might as well exit boot services now */ + status = efi_exit_boot_services(handle, &priv, exit_boot_func); + if (status != EFI_SUCCESS) + return status; + + /* Historic? */ + boot_params->alt_mem_k = 32 * 1024; + + status = setup_e820(boot_params, e820ext, e820ext_size); + if (status != EFI_SUCCESS) + return status; + + return EFI_SUCCESS; +} + +static bool have_unsupported_snp_features(void) +{ + u64 unsupported; + + unsupported = snp_get_unsupported_features(sev_get_status()); + if (unsupported) { + efi_err("Unsupported SEV-SNP features detected: 0x%llx\n", + unsupported); + return true; + } + return false; +} + +static void efi_get_seed(void *seed, int size) +{ + efi_get_random_bytes(size, seed); + + /* + * This only updates seed[0] when running on 32-bit, but in that case, + * seed[1] is not used anyway, as there is no virtual KASLR on 32-bit. + */ + *(unsigned long *)seed ^= kaslr_get_random_long("EFI"); +} + +static void error(char *str) +{ + efi_warn("Decompression failed: %s\n", str); +} + +static efi_status_t efi_decompress_kernel(unsigned long *kernel_entry) +{ + unsigned long virt_addr = LOAD_PHYSICAL_ADDR; + unsigned long addr, alloc_size, entry; + efi_status_t status; + u32 seed[2] = {}; + + /* determine the required size of the allocation */ + alloc_size = ALIGN(max_t(unsigned long, output_len, kernel_total_size), + MIN_KERNEL_ALIGN); + + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && !efi_nokaslr) { + u64 range = KERNEL_IMAGE_SIZE - LOAD_PHYSICAL_ADDR - kernel_total_size; + static const efi_char16_t ami[] = L"American Megatrends"; + + efi_get_seed(seed, sizeof(seed)); + + virt_addr += (range * seed[1]) >> 32; + virt_addr &= ~(CONFIG_PHYSICAL_ALIGN - 1); + + /* + * Older Dell systems with AMI UEFI firmware v2.0 may hang + * while decompressing the kernel if physical address + * randomization is enabled. + * + * https://bugzilla.kernel.org/show_bug.cgi?id=218173 + */ + if (efi_system_table->hdr.revision <= EFI_2_00_SYSTEM_TABLE_REVISION && + !memcmp(efistub_fw_vendor(), ami, sizeof(ami))) { + efi_debug("AMI firmware v2.0 or older detected - disabling physical KASLR\n"); + seed[0] = 0; + } + } + + status = efi_random_alloc(alloc_size, CONFIG_PHYSICAL_ALIGN, &addr, + seed[0], EFI_LOADER_CODE, + EFI_X86_KERNEL_ALLOC_LIMIT); + if (status != EFI_SUCCESS) + return status; + + entry = decompress_kernel((void *)addr, virt_addr, error); + if (entry == ULONG_MAX) { + efi_free(alloc_size, addr); + return EFI_LOAD_ERROR; + } + + *kernel_entry = addr + entry; + + efi_adjust_memory_range_protection(addr, kernel_total_size); + + return EFI_SUCCESS; +} + +static void __noreturn enter_kernel(unsigned long kernel_addr, + struct boot_params *boot_params) +{ + /* enter decompressed kernel with boot_params pointer in RSI/ESI */ + asm("jmp *%0"::"r"(kernel_addr), "S"(boot_params)); + + unreachable(); +} + +/* + * On success, this routine will jump to the relocated image directly and never + * return. On failure, it will exit to the firmware via efi_exit() instead of + * returning. + */ +void __noreturn efi_stub_entry(efi_handle_t handle, + efi_system_table_t *sys_table_arg, + struct boot_params *boot_params) +{ + efi_guid_t guid = EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID; + struct setup_header *hdr = &boot_params->hdr; + const struct linux_efi_initrd *initrd = NULL; + unsigned long kernel_entry; + efi_status_t status; + + boot_params_pointer = boot_params; + + efi_system_table = sys_table_arg; + /* Check if we were booted by the EFI firmware */ + if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) + efi_exit(handle, EFI_INVALID_PARAMETER); + + if (have_unsupported_snp_features()) + efi_exit(handle, EFI_UNSUPPORTED); + + if (IS_ENABLED(CONFIG_EFI_DXE_MEM_ATTRIBUTES)) { + efi_dxe_table = get_efi_config_table(EFI_DXE_SERVICES_TABLE_GUID); + if (efi_dxe_table && + efi_dxe_table->hdr.signature != EFI_DXE_SERVICES_TABLE_SIGNATURE) { + efi_warn("Ignoring DXE services table: invalid signature\n"); + efi_dxe_table = NULL; + } + } + + /* grab the memory attributes protocol if it exists */ + efi_bs_call(locate_protocol, &guid, NULL, (void **)&memattr); + + status = efi_setup_5level_paging(); + if (status != EFI_SUCCESS) { + efi_err("efi_setup_5level_paging() failed!\n"); + goto fail; + } + +#ifdef CONFIG_CMDLINE_BOOL + status = efi_parse_options(CONFIG_CMDLINE); + if (status != EFI_SUCCESS) { + efi_err("Failed to parse options\n"); + goto fail; + } +#endif + if (!IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) { + unsigned long cmdline_paddr = ((u64)hdr->cmd_line_ptr | + ((u64)boot_params->ext_cmd_line_ptr << 32)); + status = efi_parse_options((char *)cmdline_paddr); + if (status != EFI_SUCCESS) { + efi_err("Failed to parse options\n"); + goto fail; + } + } + + status = efi_decompress_kernel(&kernel_entry); + if (status != EFI_SUCCESS) { + efi_err("Failed to decompress kernel\n"); + goto fail; + } + + /* + * At this point, an initrd may already have been loaded by the + * bootloader and passed via bootparams. We permit an initrd loaded + * from the LINUX_EFI_INITRD_MEDIA_GUID device path to supersede it. + * + * If the device path is not present, any command-line initrd= + * arguments will be processed only if image is not NULL, which will be + * the case only if we were loaded via the PE entry point. + */ + status = efi_load_initrd(image, hdr->initrd_addr_max, ULONG_MAX, + &initrd); + if (status != EFI_SUCCESS) + goto fail; + if (initrd && initrd->size > 0) { + efi_set_u64_split(initrd->base, &hdr->ramdisk_image, + &boot_params->ext_ramdisk_image); + efi_set_u64_split(initrd->size, &hdr->ramdisk_size, + &boot_params->ext_ramdisk_size); + } + + + /* + * If the boot loader gave us a value for secure_boot then we use that, + * otherwise we ask the BIOS. + */ + if (boot_params->secure_boot == efi_secureboot_mode_unset) + boot_params->secure_boot = efi_get_secureboot(); + + /* Ask the firmware to clear memory on unclean shutdown */ + efi_enable_reset_attack_mitigation(); + + efi_random_get_seed(); + + efi_retrieve_tpm2_eventlog(); + + setup_graphics(boot_params); + + setup_efi_pci(boot_params); + + setup_quirks(boot_params); + + setup_unaccepted_memory(); + + status = exit_boot(boot_params, handle); + if (status != EFI_SUCCESS) { + efi_err("exit_boot() failed!\n"); + goto fail; + } + + /* + * Call the SEV init code while still running with the firmware's + * GDT/IDT, so #VC exceptions will be handled by EFI. + */ + sev_enable(boot_params); + + efi_5level_switch(); + + enter_kernel(kernel_entry, boot_params); +fail: + efi_err("efi_stub_entry() failed!\n"); + + efi_exit(handle, status); +} + +#ifdef CONFIG_EFI_HANDOVER_PROTOCOL +void efi_handover_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg, + struct boot_params *boot_params) +{ + extern char _bss[], _ebss[]; + + memset(_bss, 0, _ebss - _bss); + efi_stub_entry(handle, sys_table_arg, boot_params); +} + +#ifndef CONFIG_EFI_MIXED +extern __alias(efi_handover_entry) +void efi32_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg, + struct boot_params *boot_params); + +extern __alias(efi_handover_entry) +void efi64_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg, + struct boot_params *boot_params); +#endif +#endif |