/* * Common EFI (Extensible Firmware Interface) support functions * Based on Extensible Firmware Interface Specification version 1.0 * * Copyright (C) 1999 VA Linux Systems * Copyright (C) 1999 Walt Drummond * Copyright (C) 1999-2002 Hewlett-Packard Co. * David Mosberger-Tang * Stephane Eranian * Copyright (C) 2005-2008 Intel Co. * Fenghua Yu * Bibo Mao * Chandramouli Narayanan * Huang Ying * * Copied from efi_32.c to eliminate the duplicated code between EFI * 32/64 support code. --ying 2007-10-26 * * All EFI Runtime Services are not implemented yet as EFI only * supports physical mode addressing on SoftSDV. This is to be fixed * in a future version. --drummond 1999-07-20 * * Implemented EFI runtime services and virtual mode calls. --davidm * * Goutham Rao: * Skip non-WB memory and ignore empty memory ranges. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define EFI_DEBUG 1 #define PFX "EFI: " #define EFI_MIN_RESERVE 5120 #define EFI_DUMMY_GUID \ EFI_GUID(0x4424ac57, 0xbe4b, 0x47dd, 0x9e, 0x97, 0xed, 0x50, 0xf0, 0x9f, 0x92, 0xa9) static efi_char16_t efi_dummy_name[6] = { 'D', 'U', 'M', 'M', 'Y', 0 }; struct efi __read_mostly efi = { .mps = EFI_INVALID_TABLE_ADDR, .acpi = EFI_INVALID_TABLE_ADDR, .acpi20 = EFI_INVALID_TABLE_ADDR, .smbios = EFI_INVALID_TABLE_ADDR, .sal_systab = EFI_INVALID_TABLE_ADDR, .boot_info = EFI_INVALID_TABLE_ADDR, .hcdp = EFI_INVALID_TABLE_ADDR, .uga = EFI_INVALID_TABLE_ADDR, .uv_systab = EFI_INVALID_TABLE_ADDR, }; EXPORT_SYMBOL(efi); struct efi_memory_map memmap; static struct efi efi_phys __initdata; static efi_system_table_t efi_systab __initdata; static inline bool efi_is_native(void) { return IS_ENABLED(CONFIG_X86_64) == efi_enabled(EFI_64BIT); } unsigned long x86_efi_facility; /* * Returns 1 if 'facility' is enabled, 0 otherwise. */ int efi_enabled(int facility) { return test_bit(facility, &x86_efi_facility) != 0; } EXPORT_SYMBOL(efi_enabled); static bool disable_runtime = false; static int __init setup_noefi(char *arg) { disable_runtime = true; return 0; } early_param("noefi", setup_noefi); int add_efi_memmap; EXPORT_SYMBOL(add_efi_memmap); static int __init setup_add_efi_memmap(char *arg) { add_efi_memmap = 1; return 0; } early_param("add_efi_memmap", setup_add_efi_memmap); static bool efi_no_storage_paranoia; static int __init setup_storage_paranoia(char *arg) { efi_no_storage_paranoia = true; return 0; } early_param("efi_no_storage_paranoia", setup_storage_paranoia); static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc) { unsigned long flags; efi_status_t status; spin_lock_irqsave(&rtc_lock, flags); status = efi_call_virt2(get_time, tm, tc); spin_unlock_irqrestore(&rtc_lock, flags); return status; } static efi_status_t virt_efi_set_time(efi_time_t *tm) { unsigned long flags; efi_status_t status; spin_lock_irqsave(&rtc_lock, flags); status = efi_call_virt1(set_time, tm); spin_unlock_irqrestore(&rtc_lock, flags); return status; } static efi_status_t virt_efi_get_wakeup_time(efi_bool_t *enabled, efi_bool_t *pending, efi_time_t *tm) { unsigned long flags; efi_status_t status; spin_lock_irqsave(&rtc_lock, flags); status = efi_call_virt3(get_wakeup_time, enabled, pending, tm); spin_unlock_irqrestore(&rtc_lock, flags); return status; } static efi_status_t virt_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm) { unsigned long flags; efi_status_t status; spin_lock_irqsave(&rtc_lock, flags); status = efi_call_virt2(set_wakeup_time, enabled, tm); spin_unlock_irqrestore(&rtc_lock, flags); return status; } static efi_status_t virt_efi_get_variable(efi_char16_t *name, efi_guid_t *vendor, u32 *attr, unsigned long *data_size, void *data) { return efi_call_virt5(get_variable, name, vendor, attr, data_size, data); } static efi_status_t virt_efi_get_next_variable(unsigned long *name_size, efi_char16_t *name, efi_guid_t *vendor) { return efi_call_virt3(get_next_variable, name_size, name, vendor); } static efi_status_t virt_efi_set_variable(efi_char16_t *name, efi_guid_t *vendor, u32 attr, unsigned long data_size, void *data) { return efi_call_virt5(set_variable, name, vendor, attr, data_size, data); } static efi_status_t virt_efi_query_variable_info(u32 attr, u64 *storage_space, u64 *remaining_space, u64 *max_variable_size) { if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) return EFI_UNSUPPORTED; return efi_call_virt4(query_variable_info, attr, storage_space, remaining_space, max_variable_size); } static efi_status_t virt_efi_get_next_high_mono_count(u32 *count) { return efi_call_virt1(get_next_high_mono_count, count); } static void virt_efi_reset_system(int reset_type, efi_status_t status, unsigned long data_size, efi_char16_t *data) { efi_call_virt4(reset_system, reset_type, status, data_size, data); } static efi_status_t virt_efi_update_capsule(efi_capsule_header_t **capsules, unsigned long count, unsigned long sg_list) { if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) return EFI_UNSUPPORTED; return efi_call_virt3(update_capsule, capsules, count, sg_list); } static efi_status_t virt_efi_query_capsule_caps(efi_capsule_header_t **capsules, unsigned long count, u64 *max_size, int *reset_type) { if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION) return EFI_UNSUPPORTED; return efi_call_virt4(query_capsule_caps, capsules, count, max_size, reset_type); } static efi_status_t __init phys_efi_set_virtual_address_map( unsigned long memory_map_size, unsigned long descriptor_size, u32 descriptor_version, efi_memory_desc_t *virtual_map) { efi_status_t status; efi_call_phys_prelog(); status = efi_call_phys4(efi_phys.set_virtual_address_map, memory_map_size, descriptor_size, descriptor_version, virtual_map); efi_call_phys_epilog(); return status; } static efi_status_t __init phys_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc) { unsigned long flags; efi_status_t status; spin_lock_irqsave(&rtc_lock, flags); efi_call_phys_prelog(); status = efi_call_phys2(efi_phys.get_time, tm, tc); efi_call_phys_epilog(); spin_unlock_irqrestore(&rtc_lock, flags); return status; } int efi_set_rtc_mmss(unsigned long nowtime) { int real_seconds, real_minutes; efi_status_t status; efi_time_t eft; efi_time_cap_t cap; status = efi.get_time(&eft, &cap); if (status != EFI_SUCCESS) { printk(KERN_ERR "Oops: efitime: can't read time!\n"); return -1; } real_seconds = nowtime % 60; real_minutes = nowtime / 60; if (((abs(real_minutes - eft.minute) + 15)/30) & 1) real_minutes += 30; real_minutes %= 60; eft.minute = real_minutes; eft.second = real_seconds; status = efi.set_time(&eft); if (status != EFI_SUCCESS) { printk(KERN_ERR "Oops: efitime: can't write time!\n"); return -1; } return 0; } unsigned long efi_get_time(void) { efi_status_t status; efi_time_t eft; efi_time_cap_t cap; status = efi.get_time(&eft, &cap); if (status != EFI_SUCCESS) printk(KERN_ERR "Oops: efitime: can't read time!\n"); return mktime(eft.year, eft.month, eft.day, eft.hour, eft.minute, eft.second); } /* * Tell the kernel about the EFI memory map. This might include * more than the max 128 entries that can fit in the e820 legacy * (zeropage) memory map. */ static void __init do_add_efi_memmap(void) { void *p; for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) { efi_memory_desc_t *md = p; unsigned long long start = md->phys_addr; unsigned long long size = md->num_pages << EFI_PAGE_SHIFT; int e820_type; switch (md->type) { case EFI_LOADER_CODE: case EFI_LOADER_DATA: case EFI_BOOT_SERVICES_CODE: case EFI_BOOT_SERVICES_DATA: case EFI_CONVENTIONAL_MEMORY: if (md->attribute & EFI_MEMORY_WB) e820_type = E820_RAM; else e820_type = E820_RESERVED; break; case EFI_ACPI_RECLAIM_MEMORY: e820_type = E820_ACPI; break; case EFI_ACPI_MEMORY_NVS: e820_type = E820_NVS; break; case EFI_UNUSABLE_MEMORY: e820_type = E820_UNUSABLE; break; default: /* * EFI_RESERVED_TYPE EFI_RUNTIME_SERVICES_CODE * EFI_RUNTIME_SERVICES_DATA EFI_MEMORY_MAPPED_IO * EFI_MEMORY_MAPPED_IO_PORT_SPACE EFI_PAL_CODE */ e820_type = E820_RESERVED; break; } e820_add_region(start, size, e820_type); } sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map); } void __init efi_memblock_x86_reserve_range(void) { unsigned long pmap; #ifdef CONFIG_X86_32 pmap = boot_params.efi_info.efi_memmap; #else pmap = (boot_params.efi_info.efi_memmap | ((__u64)boot_params.efi_info.efi_memmap_hi<<32)); #endif memmap.phys_map = (void *)pmap; memmap.nr_map = boot_params.efi_info.efi_memmap_size / boot_params.efi_info.efi_memdesc_size; memmap.desc_version = boot_params.efi_info.efi_memdesc_version; memmap.desc_size = boot_params.efi_info.efi_memdesc_size; memblock_x86_reserve_range(pmap, pmap + memmap.nr_map * memmap.desc_size, "EFI memmap"); } #if EFI_DEBUG static void __init print_efi_memmap(void) { efi_memory_desc_t *md; void *p; int i; for (p = memmap.map, i = 0; p < memmap.map_end; p += memmap.desc_size, i++) { md = p; printk(KERN_INFO PFX "mem%02u: type=%u, attr=0x%llx, " "range=[0x%016llx-0x%016llx) (%lluMB)\n", i, md->type, md->attribute, md->phys_addr, md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT), (md->num_pages >> (20 - EFI_PAGE_SHIFT))); } } #endif /* EFI_DEBUG */ void __init efi_reserve_boot_services(void) { void *p; for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) { efi_memory_desc_t *md = p; u64 start = md->phys_addr; u64 size = md->num_pages << EFI_PAGE_SHIFT; if (md->type != EFI_BOOT_SERVICES_CODE && md->type != EFI_BOOT_SERVICES_DATA) continue; /* Only reserve where possible: * - Not within any already allocated areas * - Not over any memory area (really needed, if above?) * - Not within any part of the kernel * - Not the bios reserved area */ if ((start+size >= virt_to_phys(_text) && start <= virt_to_phys(_end)) || !e820_all_mapped(start, start+size, E820_RAM) || memblock_x86_check_reserved_size(&start, &size, 1<num_pages = 0; memblock_dbg(PFX "Could not reserve boot range " "[0x%010llx-0x%010llx]\n", start, start+size-1); } else memblock_x86_reserve_range(start, start+size, "EFI Boot"); } } static void __init efi_free_boot_services(void) { void *p; for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) { efi_memory_desc_t *md = p; unsigned long long start = md->phys_addr; unsigned long long size = md->num_pages << EFI_PAGE_SHIFT; if (md->type != EFI_BOOT_SERVICES_CODE && md->type != EFI_BOOT_SERVICES_DATA) continue; /* Could not reserve boot area */ if (!size) continue; free_bootmem_late(start, size); } } void __init efi_init(void) { efi_config_table_t *config_tables; efi_runtime_services_t *runtime; efi_char16_t *c16; char vendor[100] = "unknown"; int i = 0; void *tmp; if (!efi_is_native()) return; #ifdef CONFIG_X86_32 efi_phys.systab = (efi_system_table_t *)boot_params.efi_info.efi_systab; #else efi_phys.systab = (efi_system_table_t *) (boot_params.efi_info.efi_systab | ((__u64)boot_params.efi_info.efi_systab_hi<<32)); #endif efi.systab = early_ioremap((unsigned long)efi_phys.systab, sizeof(efi_system_table_t)); if (efi.systab == NULL) printk(KERN_ERR "Couldn't map the EFI system table!\n"); memcpy(&efi_systab, efi.systab, sizeof(efi_system_table_t)); early_iounmap(efi.systab, sizeof(efi_system_table_t)); efi.systab = &efi_systab; /* * Verify the EFI Table */ if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) printk(KERN_ERR "EFI system table signature incorrect!\n"); if ((efi.systab->hdr.revision >> 16) == 0) printk(KERN_ERR "Warning: EFI system table version " "%d.%02d, expected 1.00 or greater!\n", efi.systab->hdr.revision >> 16, efi.systab->hdr.revision & 0xffff); set_bit(EFI_SYSTEM_TABLES, &x86_efi_facility); /* * Show what we know for posterity */ c16 = tmp = early_ioremap(efi.systab->fw_vendor, 2); if (c16) { for (i = 0; i < sizeof(vendor) - 1 && *c16; ++i) vendor[i] = *c16++; vendor[i] = '\0'; } else printk(KERN_ERR PFX "Could not map the firmware vendor!\n"); early_iounmap(tmp, 2); printk(KERN_INFO "EFI v%u.%.02u by %s\n", efi.systab->hdr.revision >> 16, efi.systab->hdr.revision & 0xffff, vendor); /* * Let's see what config tables the firmware passed to us. */ config_tables = early_ioremap( efi.systab->tables, efi.systab->nr_tables * sizeof(efi_config_table_t)); if (config_tables == NULL) printk(KERN_ERR "Could not map EFI Configuration Table!\n"); printk(KERN_INFO); for (i = 0; i < efi.systab->nr_tables; i++) { if (!efi_guidcmp(config_tables[i].guid, MPS_TABLE_GUID)) { efi.mps = config_tables[i].table; printk(" MPS=0x%lx ", config_tables[i].table); } else if (!efi_guidcmp(config_tables[i].guid, ACPI_20_TABLE_GUID)) { efi.acpi20 = config_tables[i].table; printk(" ACPI 2.0=0x%lx ", config_tables[i].table); } else if (!efi_guidcmp(config_tables[i].guid, ACPI_TABLE_GUID)) { efi.acpi = config_tables[i].table; printk(" ACPI=0x%lx ", config_tables[i].table); } else if (!efi_guidcmp(config_tables[i].guid, SMBIOS_TABLE_GUID)) { efi.smbios = config_tables[i].table; printk(" SMBIOS=0x%lx ", config_tables[i].table); #ifdef CONFIG_X86_UV } else if (!efi_guidcmp(config_tables[i].guid, UV_SYSTEM_TABLE_GUID)) { efi.uv_systab = config_tables[i].table; printk(" UVsystab=0x%lx ", config_tables[i].table); #endif } else if (!efi_guidcmp(config_tables[i].guid, HCDP_TABLE_GUID)) { efi.hcdp = config_tables[i].table; printk(" HCDP=0x%lx ", config_tables[i].table); } else if (!efi_guidcmp(config_tables[i].guid, UGA_IO_PROTOCOL_GUID)) { efi.uga = config_tables[i].table; printk(" UGA=0x%lx ", config_tables[i].table); } } printk("\n"); early_iounmap(config_tables, efi.systab->nr_tables * sizeof(efi_config_table_t)); set_bit(EFI_CONFIG_TABLES, &x86_efi_facility); if (!disable_runtime) { /* * Check out the runtime services table. We need to map * the runtime services table so that we can grab the physical * address of several of the EFI runtime functions, needed to * set the firmware into virtual mode. */ runtime = early_ioremap((unsigned long)efi.systab->runtime, sizeof(efi_runtime_services_t)); if (runtime != NULL) { /* * We will only need *early* access to the following * two EFI runtime services before set_virtual_address_map * is invoked. */ efi_phys.get_time = (efi_get_time_t *)runtime->get_time; efi_phys.set_virtual_address_map = (efi_set_virtual_address_map_t *) runtime->set_virtual_address_map; /* * Make efi_get_time can be called before entering * virtual mode. */ efi.get_time = phys_efi_get_time; set_bit(EFI_RUNTIME_SERVICES, &x86_efi_facility); } else printk(KERN_ERR "Could not map the EFI runtime service " "table!\n"); early_iounmap(runtime, sizeof(efi_runtime_services_t)); } /* Map the EFI memory map */ memmap.map = early_ioremap((unsigned long)memmap.phys_map, memmap.nr_map * memmap.desc_size); if (memmap.map == NULL) printk(KERN_ERR "Could not map the EFI memory map!\n"); memmap.map_end = memmap.map + (memmap.nr_map * memmap.desc_size); if (memmap.desc_size != sizeof(efi_memory_desc_t)) printk(KERN_WARNING "Kernel-defined memdesc doesn't match the one from EFI!\n"); if (add_efi_memmap) do_add_efi_memmap(); set_bit(EFI_MEMMAP, &x86_efi_facility); #ifdef CONFIG_X86_32 x86_platform.get_wallclock = efi_get_time; x86_platform.set_wallclock = efi_set_rtc_mmss; #endif #if EFI_DEBUG print_efi_memmap(); #endif } void __init efi_set_executable(efi_memory_desc_t *md, bool executable) { u64 addr, npages; addr = md->virt_addr; npages = md->num_pages; memrange_efi_to_native(&addr, &npages); if (executable) set_memory_x(addr, npages); else set_memory_nx(addr, npages); } static void __init runtime_code_page_mkexec(void) { efi_memory_desc_t *md; void *p; /* Make EFI runtime service code area executable */ for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) { md = p; if (md->type != EFI_RUNTIME_SERVICES_CODE) continue; efi_set_executable(md, true); } } /* * This function will switch the EFI runtime services to virtual mode. * Essentially, look through the EFI memmap and map every region that * has the runtime attribute bit set in its memory descriptor and update * that memory descriptor with the virtual address obtained from ioremap(). * This enables the runtime services to be called without having to * thunk back into physical mode for every invocation. */ void __init efi_enter_virtual_mode(void) { efi_memory_desc_t *md, *prev_md = NULL; efi_status_t status; unsigned long size; u64 end, systab, addr, npages, end_pfn; void *p, *va, *new_memmap = NULL; int count = 0; efi.systab = NULL; /* Merge contiguous regions of the same type and attribute */ for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) { u64 prev_size; md = p; if (!prev_md) { prev_md = md; continue; } if (prev_md->type != md->type || prev_md->attribute != md->attribute) { prev_md = md; continue; } prev_size = prev_md->num_pages << EFI_PAGE_SHIFT; if (md->phys_addr == (prev_md->phys_addr + prev_size)) { prev_md->num_pages += md->num_pages; md->type = EFI_RESERVED_TYPE; md->attribute = 0; continue; } prev_md = md; } for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) { md = p; if (!(md->attribute & EFI_MEMORY_RUNTIME) && md->type != EFI_BOOT_SERVICES_CODE && md->type != EFI_BOOT_SERVICES_DATA) continue; size = md->num_pages << EFI_PAGE_SHIFT; end = md->phys_addr + size; end_pfn = PFN_UP(end); if (end_pfn <= max_low_pfn_mapped || (end_pfn > (1UL << (32 - PAGE_SHIFT)) && end_pfn <= max_pfn_mapped)) va = __va(md->phys_addr); else va = efi_ioremap(md->phys_addr, size, md->type); md->virt_addr = (u64) (unsigned long) va; if (!va) { printk(KERN_ERR PFX "ioremap of 0x%llX failed!\n", (unsigned long long)md->phys_addr); continue; } if (!(md->attribute & EFI_MEMORY_WB)) { addr = md->virt_addr; npages = md->num_pages; memrange_efi_to_native(&addr, &npages); set_memory_uc(addr, npages); } systab = (u64) (unsigned long) efi_phys.systab; if (md->phys_addr <= systab && systab < end) { systab += md->virt_addr - md->phys_addr; efi.systab = (efi_system_table_t *) (unsigned long) systab; } new_memmap = krealloc(new_memmap, (count + 1) * memmap.desc_size, GFP_KERNEL); memcpy(new_memmap + (count * memmap.desc_size), md, memmap.desc_size); count++; } BUG_ON(!efi.systab); status = phys_efi_set_virtual_address_map( memmap.desc_size * count, memmap.desc_size, memmap.desc_version, (efi_memory_desc_t *)__pa(new_memmap)); if (status != EFI_SUCCESS) { printk(KERN_ALERT "Unable to switch EFI into virtual mode " "(status=%lx)!\n", status); panic("EFI call to SetVirtualAddressMap() failed!"); } /* * Thankfully, it does seem that no runtime services other than * SetVirtualAddressMap() will touch boot services code, so we can * get rid of it all at this point */ efi_free_boot_services(); /* * Now that EFI is in virtual mode, update the function * pointers in the runtime service table to the new virtual addresses. * * Call EFI services through wrapper functions. */ efi.runtime_version = efi_systab.hdr.revision; efi.get_time = virt_efi_get_time; efi.set_time = virt_efi_set_time; efi.get_wakeup_time = virt_efi_get_wakeup_time; efi.set_wakeup_time = virt_efi_set_wakeup_time; efi.get_variable = virt_efi_get_variable; efi.get_next_variable = virt_efi_get_next_variable; efi.set_variable = virt_efi_set_variable; efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count; efi.reset_system = virt_efi_reset_system; efi.set_virtual_address_map = NULL; efi.query_variable_info = virt_efi_query_variable_info; efi.update_capsule = virt_efi_update_capsule; efi.query_capsule_caps = virt_efi_query_capsule_caps; if (__supported_pte_mask & _PAGE_NX) runtime_code_page_mkexec(); clear_bit(EFI_MEMMAP, &x86_efi_facility); early_iounmap(memmap.map, memmap.nr_map * memmap.desc_size); memmap.map = NULL; kfree(new_memmap); /* clean DUMMY object */ efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID, EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS, 0, NULL); } /* * Convenience functions to obtain memory types and attributes */ u32 efi_mem_type(unsigned long phys_addr) { efi_memory_desc_t *md; void *p; if (!efi_enabled(EFI_MEMMAP)) return 0; for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) { md = p; if ((md->phys_addr <= phys_addr) && (phys_addr < (md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT)))) return md->type; } return 0; } u64 efi_mem_attributes(unsigned long phys_addr) { efi_memory_desc_t *md; void *p; for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) { md = p; if ((md->phys_addr <= phys_addr) && (phys_addr < (md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT)))) return md->attribute; } return 0; } /* * Some firmware has serious problems when using more than 50% of the EFI * variable store, i.e. it triggers bugs that can brick machines. Ensure that * we never use more than this 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) { efi_status_t status; u64 storage_size, remaining_size, max_size; if (!(attributes & EFI_VARIABLE_NON_VOLATILE)) return 0; status = efi.query_variable_info(attributes, &storage_size, &remaining_size, &max_size); if (status != EFI_SUCCESS) return status; /* * Some firmware implementations refuse to boot if there's insufficient * space in the variable store. 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_ATOMIC); if (!dummy) return EFI_OUT_OF_RESOURCES; status = efi.set_variable(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.set_variable(efi_dummy_name, &EFI_DUMMY_GUID, EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS, 0, dummy); } 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);