// SPDX-License-Identifier: GPL-2.0-only #define pr_fmt(fmt) "efi: " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define EFI_MIN_RESERVE 5120 #define EFI_DUMMY_GUID \ EFI_GUID(0x4424ac57, 0xbe4b, 0x47dd, 0x9e, 0x97, 0xed, 0x50, 0xf0, 0x9f, 0x92, 0xa9) #define QUARK_CSH_SIGNATURE 0x5f435348 /* _CSH */ #define QUARK_SECURITY_HEADER_SIZE 0x400 /* * Header prepended to the standard EFI capsule on Quark systems the are based * on Intel firmware BSP. * @csh_signature: Unique identifier to sanity check signed module * presence ("_CSH"). * @version: Current version of CSH used. Should be one for Quark A0. * @modulesize: Size of the entire module including the module header * and payload. * @security_version_number_index: Index of SVN to use for validation of signed * module. * @security_version_number: Used to prevent against roll back of modules. * @rsvd_module_id: Currently unused for Clanton (Quark). * @rsvd_module_vendor: Vendor Identifier. For Intel products value is * 0x00008086. * @rsvd_date: BCD representation of build date as yyyymmdd, where * yyyy=4 digit year, mm=1-12, dd=1-31. * @headersize: Total length of the header including including any * padding optionally added by the signing tool. * @hash_algo: What Hash is used in the module signing. * @cryp_algo: What Crypto is used in the module signing. * @keysize: Total length of the key data including including any * padding optionally added by the signing tool. * @signaturesize: Total length of the signature including including any * padding optionally added by the signing tool. * @rsvd_next_header: 32-bit pointer to the next Secure Boot Module in the * chain, if there is a next header. * @rsvd: Reserved, padding structure to required size. * * See also QuartSecurityHeader_t in * Quark_EDKII_v1.2.1.1/QuarkPlatformPkg/Include/QuarkBootRom.h * from https://downloadcenter.intel.com/download/23197/Intel-Quark-SoC-X1000-Board-Support-Package-BSP */ struct quark_security_header { u32 csh_signature; u32 version; u32 modulesize; u32 security_version_number_index; u32 security_version_number; u32 rsvd_module_id; u32 rsvd_module_vendor; u32 rsvd_date; u32 headersize; u32 hash_algo; u32 cryp_algo; u32 keysize; u32 signaturesize; u32 rsvd_next_header; u32 rsvd[2]; }; static const efi_char16_t efi_dummy_name[] = L"DUMMY"; static bool efi_no_storage_paranoia; /* * Some firmware implementations refuse to boot if there's insufficient * space in the variable store. The implementation of garbage collection * in some FW versions causes stale (deleted) variables to take up space * longer than intended and space is only freed once the store becomes * almost completely full. * * Enabling this option disables the space checks in * efi_query_variable_store() and forces garbage collection. * * Only enable this option if deleting EFI variables does not free up * space in your variable store, e.g. if despite deleting variables * you're unable to create new ones. */ static int __init setup_storage_paranoia(char *arg) { efi_no_storage_paranoia = true; return 0; } early_param("efi_no_storage_paranoia", setup_storage_paranoia); /* * Deleting the dummy variable which kicks off garbage collection */ void efi_delete_dummy_variable(void) { efi.set_variable_nonblocking((efi_char16_t *)efi_dummy_name, &EFI_DUMMY_GUID, EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS, 0, NULL); } u64 efivar_reserved_space(void) { if (efi_no_storage_paranoia) return 0; return EFI_MIN_RESERVE; } EXPORT_SYMBOL_GPL(efivar_reserved_space); /* * In the nonblocking case we do not attempt to perform garbage * collection if we do not have enough free space. Rather, we do the * bare minimum check and give up immediately if the available space * is below EFI_MIN_RESERVE. * * This function is intended to be small and simple because it is * invoked from crash handler paths. */ static efi_status_t query_variable_store_nonblocking(u32 attributes, unsigned long size) { efi_status_t status; u64 storage_size, remaining_size, max_size; status = efi.query_variable_info_nonblocking(attributes, &storage_size, &remaining_size, &max_size); if (status != EFI_SUCCESS) return status; if (remaining_size - size < EFI_MIN_RESERVE) return EFI_OUT_OF_RESOURCES; return EFI_SUCCESS; } /* * Some firmware implementations refuse to boot if there's insufficient space * in the variable store. Ensure that we never use more than a safe limit. * * Return EFI_SUCCESS if it is safe to write 'size' bytes to the variable * store. */ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size, bool nonblocking) { efi_status_t status; u64 storage_size, remaining_size, max_size; if (!(attributes & EFI_VARIABLE_NON_VOLATILE)) return 0; if (nonblocking) return query_variable_store_nonblocking(attributes, size); status = efi.query_variable_info(attributes, &storage_size, &remaining_size, &max_size); if (status != EFI_SUCCESS) return status; /* * We account for that by refusing the write if permitting it would * reduce the available space to under 5KB. This figure was provided by * Samsung, so should be safe. */ if ((remaining_size - size < EFI_MIN_RESERVE) && !efi_no_storage_paranoia) { /* * Triggering garbage collection may require that the firmware * generate a real EFI_OUT_OF_RESOURCES error. We can force * that by attempting to use more space than is available. */ unsigned long dummy_size = remaining_size + 1024; void *dummy = kzalloc(dummy_size, GFP_KERNEL); if (!dummy) return EFI_OUT_OF_RESOURCES; status = efi.set_variable((efi_char16_t *)efi_dummy_name, &EFI_DUMMY_GUID, EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS, dummy_size, dummy); if (status == EFI_SUCCESS) { /* * This should have failed, so if it didn't make sure * that we delete it... */ efi_delete_dummy_variable(); } kfree(dummy); /* * The runtime code may now have triggered a garbage collection * run, so check the variable info again */ status = efi.query_variable_info(attributes, &storage_size, &remaining_size, &max_size); if (status != EFI_SUCCESS) return status; /* * There still isn't enough room, so return an error */ if (remaining_size - size < EFI_MIN_RESERVE) return EFI_OUT_OF_RESOURCES; } return EFI_SUCCESS; } EXPORT_SYMBOL_GPL(efi_query_variable_store); /* * The UEFI specification makes it clear that the operating system is * free to do whatever it wants with boot services code after * ExitBootServices() has been called. Ignoring this recommendation a * significant bunch of EFI implementations continue calling into boot * services code (SetVirtualAddressMap). In order to work around such * buggy implementations we reserve boot services region during EFI * init and make sure it stays executable. Then, after * SetVirtualAddressMap(), it is discarded. * * However, some boot services regions contain data that is required * by drivers, so we need to track which memory ranges can never be * freed. This is done by tagging those regions with the * EFI_MEMORY_RUNTIME attribute. * * Any driver that wants to mark a region as reserved must use * efi_mem_reserve() which will insert a new EFI memory descriptor * into efi.memmap (splitting existing regions if necessary) and tag * it with EFI_MEMORY_RUNTIME. */ void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size) { struct efi_memory_map_data data = { 0 }; struct efi_mem_range mr; efi_memory_desc_t md; int num_entries; void *new; if (efi_mem_desc_lookup(addr, &md) || md.type != EFI_BOOT_SERVICES_DATA) { pr_err("Failed to lookup EFI memory descriptor for %pa\n", &addr); return; } if (addr + size > md.phys_addr + (md.num_pages << EFI_PAGE_SHIFT)) { pr_err("Region spans EFI memory descriptors, %pa\n", &addr); return; } size += addr % EFI_PAGE_SIZE; size = round_up(size, EFI_PAGE_SIZE); addr = round_down(addr, EFI_PAGE_SIZE); mr.range.start = addr; mr.range.end = addr + size - 1; mr.attribute = md.attribute | EFI_MEMORY_RUNTIME; num_entries = efi_memmap_split_count(&md, &mr.range); num_entries += efi.memmap.nr_map; if (efi_memmap_alloc(num_entries, &data) != 0) { pr_err("Could not allocate boot services memmap\n"); return; } new = early_memremap_prot(data.phys_map, data.size, pgprot_val(pgprot_encrypted(FIXMAP_PAGE_NORMAL))); if (!new) { pr_err("Failed to map new boot services memmap\n"); return; } efi_memmap_insert(&efi.memmap, new, &mr); early_memunmap(new, data.size); efi_memmap_install(&data); e820__range_update(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED); e820__update_table(e820_table); } /* * Helper function for efi_reserve_boot_services() to figure out if we * can free regions in efi_free_boot_services(). * * Use this function to ensure we do not free regions owned by somebody * else. We must only reserve (and then free) regions: * * - Not within any part of the kernel * - Not the BIOS reserved area (E820_TYPE_RESERVED, E820_TYPE_NVS, etc) */ static __init bool can_free_region(u64 start, u64 size) { if (start + size > __pa_symbol(_text) && start <= __pa_symbol(_end)) return false; if (!e820__mapped_all(start, start+size, E820_TYPE_RAM)) return false; return true; } void __init efi_reserve_boot_services(void) { efi_memory_desc_t *md; if (!efi_enabled(EFI_MEMMAP)) return; for_each_efi_memory_desc(md) { u64 start = md->phys_addr; u64 size = md->num_pages << EFI_PAGE_SHIFT; bool already_reserved; if (md->type != EFI_BOOT_SERVICES_CODE && md->type != EFI_BOOT_SERVICES_DATA) continue; already_reserved = memblock_is_region_reserved(start, size); /* * Because the following memblock_reserve() is paired * with memblock_free_late() for this region in * efi_free_boot_services(), we must be extremely * careful not to reserve, and subsequently free, * critical regions of memory (like the kernel image) or * those regions that somebody else has already * reserved. * * A good example of a critical region that must not be * freed is page zero (first 4Kb of memory), which may * contain boot services code/data but is marked * E820_TYPE_RESERVED by trim_bios_range(). */ if (!already_reserved) { memblock_reserve(start, size); /* * If we are the first to reserve the region, no * one else cares about it. We own it and can * free it later. */ if (can_free_region(start, size)) continue; } /* * We don't own the region. We must not free it. * * Setting this bit for a boot services region really * doesn't make sense as far as the firmware is * concerned, but it does provide us with a way to tag * those regions that must not be paired with * memblock_free_late(). */ md->attribute |= EFI_MEMORY_RUNTIME; } } /* * Apart from having VA mappings for EFI boot services code/data regions, * (duplicate) 1:1 mappings were also created as a quirk for buggy firmware. So, * unmap both 1:1 and VA mappings. */ static void __init efi_unmap_pages(efi_memory_desc_t *md) { pgd_t *pgd = efi_mm.pgd; u64 pa = md->phys_addr; u64 va = md->virt_addr; /* * EFI mixed mode has all RAM mapped to access arguments while making * EFI runtime calls, hence don't unmap EFI boot services code/data * regions. */ if (efi_is_mixed()) return; if (kernel_unmap_pages_in_pgd(pgd, pa, md->num_pages)) pr_err("Failed to unmap 1:1 mapping for 0x%llx\n", pa); if (kernel_unmap_pages_in_pgd(pgd, va, md->num_pages)) pr_err("Failed to unmap VA mapping for 0x%llx\n", va); } void __init efi_free_boot_services(void) { struct efi_memory_map_data data = { 0 }; efi_memory_desc_t *md; int num_entries = 0; void *new, *new_md; /* Keep all regions for /sys/kernel/debug/efi */ if (efi_enabled(EFI_DBG)) return; for_each_efi_memory_desc(md) { unsigned long long start = md->phys_addr; unsigned long long size = md->num_pages << EFI_PAGE_SHIFT; size_t rm_size; if (md->type != EFI_BOOT_SERVICES_CODE && md->type != EFI_BOOT_SERVICES_DATA) { num_entries++; continue; } /* Do not free, someone else owns it: */ if (md->attribute & EFI_MEMORY_RUNTIME) { num_entries++; continue; } /* * Before calling set_virtual_address_map(), EFI boot services * code/data regions were mapped as a quirk for buggy firmware. * Unmap them from efi_pgd before freeing them up. */ efi_unmap_pages(md); /* * Nasty quirk: if all sub-1MB memory is used for boot * services, we can get here without having allocated the * real mode trampoline. It's too late to hand boot services * memory back to the memblock allocator, so instead * try to manually allocate the trampoline if needed. * * I've seen this on a Dell XPS 13 9350 with firmware * 1.4.4 with SGX enabled booting Linux via Fedora 24's * grub2-efi on a hard disk. (And no, I don't know why * this happened, but Linux should still try to boot rather * panicking early.) */ rm_size = real_mode_size_needed(); if (rm_size && (start + rm_size) < (1<<20) && size >= rm_size) { set_real_mode_mem(start); start += rm_size; size -= rm_size; } /* * Don't free memory under 1M for two reasons: * - BIOS might clobber it * - Crash kernel needs it to be reserved */ if (start + size < SZ_1M) continue; if (start < SZ_1M) { size -= (SZ_1M - start); start = SZ_1M; } memblock_free_late(start, size); } if (!num_entries) return; if (efi_memmap_alloc(num_entries, &data) != 0) { pr_err("Failed to allocate new EFI memmap\n"); return; } new = memremap(data.phys_map, data.size, MEMREMAP_WB); if (!new) { pr_err("Failed to map new EFI memmap\n"); return; } /* * Build a new EFI memmap that excludes any boot services * regions that are not tagged EFI_MEMORY_RUNTIME, since those * regions have now been freed. */ new_md = new; for_each_efi_memory_desc(md) { if (!(md->attribute & EFI_MEMORY_RUNTIME) && (md->type == EFI_BOOT_SERVICES_CODE || md->type == EFI_BOOT_SERVICES_DATA)) continue; memcpy(new_md, md, efi.memmap.desc_size); new_md += efi.memmap.desc_size; } memunmap(new); if (efi_memmap_install(&data) != 0) { pr_err("Could not install new EFI memmap\n"); return; } } /* * A number of config table entries get remapped to virtual addresses * after entering EFI virtual mode. However, the kexec kernel requires * their physical addresses therefore we pass them via setup_data and * correct those entries to their respective physical addresses here. * * Currently only handles smbios which is necessary for some firmware * implementation. */ int __init efi_reuse_config(u64 tables, int nr_tables) { int i, sz, ret = 0; void *p, *tablep; struct efi_setup_data *data; if (nr_tables == 0) return 0; if (!efi_setup) return 0; if (!efi_enabled(EFI_64BIT)) return 0; data = early_memremap(efi_setup, sizeof(*data)); if (!data) { ret = -ENOMEM; goto out; } if (!data->smbios) goto out_memremap; sz = sizeof(efi_config_table_64_t); p = tablep = early_memremap(tables, nr_tables * sz); if (!p) { pr_err("Could not map Configuration table!\n"); ret = -ENOMEM; goto out_memremap; } for (i = 0; i < nr_tables; i++) { efi_guid_t guid; guid = ((efi_config_table_64_t *)p)->guid; if (!efi_guidcmp(guid, SMBIOS_TABLE_GUID)) ((efi_config_table_64_t *)p)->table = data->smbios; p += sz; } early_memunmap(tablep, nr_tables * sz); out_memremap: early_memunmap(data, sizeof(*data)); out: return ret; } void __init efi_apply_memmap_quirks(void) { /* * Once setup is done earlier, unmap the EFI memory map on mismatched * firmware/kernel architectures since there is no support for runtime * services. */ if (!efi_runtime_supported()) { pr_info("Setup done, disabling due to 32/64-bit mismatch\n"); efi_memmap_unmap(); } } /* * For most modern platforms the preferred method of powering off is via * ACPI. However, there are some that are known to require the use of * EFI runtime services and for which ACPI does not work at all. * * Using EFI is a last resort, to be used only if no other option * exists. */ bool efi_reboot_required(void) { if (!acpi_gbl_reduced_hardware) return false; efi_reboot_quirk_mode = EFI_RESET_WARM; return true; } bool efi_poweroff_required(void) { return acpi_gbl_reduced_hardware || acpi_no_s5; } #ifdef CONFIG_EFI_CAPSULE_QUIRK_QUARK_CSH static int qrk_capsule_setup_info(struct capsule_info *cap_info, void **pkbuff, size_t hdr_bytes) { struct quark_security_header *csh = *pkbuff; /* Only process data block that is larger than the security header */ if (hdr_bytes < sizeof(struct quark_security_header)) return 0; if (csh->csh_signature != QUARK_CSH_SIGNATURE || csh->headersize != QUARK_SECURITY_HEADER_SIZE) return 1; /* Only process data block if EFI header is included */ if (hdr_bytes < QUARK_SECURITY_HEADER_SIZE + sizeof(efi_capsule_header_t)) return 0; pr_debug("Quark security header detected\n"); if (csh->rsvd_next_header != 0) { pr_err("multiple Quark security headers not supported\n"); return -EINVAL; } *pkbuff += csh->headersize; cap_info->total_size = csh->headersize; /* * Update the first page pointer to skip over the CSH header. */ cap_info->phys[0] += csh->headersize; /* * cap_info->capsule should point at a virtual mapping of the entire * capsule, starting at the capsule header. Our image has the Quark * security header prepended, so we cannot rely on the default vmap() * mapping created by the generic capsule code. * Given that the Quark firmware does not appear to care about the * virtual mapping, let's just point cap_info->capsule at our copy * of the capsule header. */ cap_info->capsule = &cap_info->header; return 1; } static const struct x86_cpu_id efi_capsule_quirk_ids[] = { X86_MATCH_VFM(INTEL_QUARK_X1000, &qrk_capsule_setup_info), { } }; int efi_capsule_setup_info(struct capsule_info *cap_info, void *kbuff, size_t hdr_bytes) { int (*quirk_handler)(struct capsule_info *, void **, size_t); const struct x86_cpu_id *id; int ret; if (hdr_bytes < sizeof(efi_capsule_header_t)) return 0; cap_info->total_size = 0; id = x86_match_cpu(efi_capsule_quirk_ids); if (id) { /* * The quirk handler is supposed to return * - a value > 0 if the setup should continue, after advancing * kbuff as needed * - 0 if not enough hdr_bytes are available yet * - a negative error code otherwise */ quirk_handler = (typeof(quirk_handler))id->driver_data; ret = quirk_handler(cap_info, &kbuff, hdr_bytes); if (ret <= 0) return ret; } memcpy(&cap_info->header, kbuff, sizeof(cap_info->header)); cap_info->total_size += cap_info->header.imagesize; return __efi_capsule_setup_info(cap_info); } #endif /* * If any access by any efi runtime service causes a page fault, then, * 1. If it's efi_reset_system(), reboot through BIOS. * 2. If any other efi runtime service, then * a. Return error status to the efi caller process. * b. Disable EFI Runtime Services forever and * c. Freeze efi_rts_wq and schedule new process. * * @return: Returns, if the page fault is not handled. This function * will never return if the page fault is handled successfully. */ void efi_crash_gracefully_on_page_fault(unsigned long phys_addr) { if (!IS_ENABLED(CONFIG_X86_64)) return; /* * If we get an interrupt/NMI while processing an EFI runtime service * then this is a regular OOPS, not an EFI failure. */ if (in_interrupt()) return; /* * Make sure that an efi runtime service caused the page fault. * READ_ONCE() because we might be OOPSing in a different thread, * and we don't want to trip KTSAN while trying to OOPS. */ if (READ_ONCE(efi_rts_work.efi_rts_id) == EFI_NONE || current_work() != &efi_rts_work.work) return; /* * Address range 0x0000 - 0x0fff is always mapped in the efi_pgd, so * page faulting on these addresses isn't expected. */ if (phys_addr <= 0x0fff) return; /* * Print stack trace as it might be useful to know which EFI Runtime * Service is buggy. */ WARN(1, FW_BUG "Page fault caused by firmware at PA: 0x%lx\n", phys_addr); /* * Buggy efi_reset_system() is handled differently from other EFI * Runtime Services as it doesn't use efi_rts_wq. Although, * native_machine_emergency_restart() says that machine_real_restart() * could fail, it's better not to complicate this fault handler * because this case occurs *very* rarely and hence could be improved * on a need by basis. */ if (efi_rts_work.efi_rts_id == EFI_RESET_SYSTEM) { pr_info("efi_reset_system() buggy! Reboot through BIOS\n"); machine_real_restart(MRR_BIOS); return; } /* * Before calling EFI Runtime Service, the kernel has switched the * calling process to efi_mm. Hence, switch back to task_mm. */ arch_efi_call_virt_teardown(); /* Signal error status to the efi caller process */ efi_rts_work.status = EFI_ABORTED; complete(&efi_rts_work.efi_rts_comp); clear_bit(EFI_RUNTIME_SERVICES, &efi.flags); pr_info("Froze efi_rts_wq and disabled EFI Runtime Services\n"); /* * Call schedule() in an infinite loop, so that any spurious wake ups * will never run efi_rts_wq again. */ for (;;) { set_current_state(TASK_IDLE); schedule(); } }