/* * 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 * Copyright (C) 2013 SuSE Labs * Borislav Petkov - runtime services VA mapping * * 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. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define EFI_DEBUG struct efi_memory_map memmap; static struct efi efi_phys __initdata; static efi_system_table_t efi_systab __initdata; static efi_config_table_type_t arch_tables[] __initdata = { #ifdef CONFIG_X86_UV {UV_SYSTEM_TABLE_GUID, "UVsystab", &efi.uv_systab}, #endif {NULL_GUID, NULL, NULL}, }; u64 efi_setup; /* efi setup_data physical address */ static bool disable_runtime __initdata = 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 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_virt(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_virt(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_virt(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_virt(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_virt(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_virt(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_virt(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_virt(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_virt(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_virt(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_virt(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_virt(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_phys(efi_phys.set_virtual_address_map, memory_map_size, descriptor_size, descriptor_version, virtual_map); efi_call_phys_epilog(); return status; } int efi_set_rtc_mmss(const struct timespec *now) { unsigned long nowtime = now->tv_sec; efi_status_t status; efi_time_t eft; efi_time_cap_t cap; struct rtc_time tm; status = efi.get_time(&eft, &cap); if (status != EFI_SUCCESS) { pr_err("Oops: efitime: can't read time!\n"); return -1; } rtc_time_to_tm(nowtime, &tm); if (!rtc_valid_tm(&tm)) { eft.year = tm.tm_year + 1900; eft.month = tm.tm_mon + 1; eft.day = tm.tm_mday; eft.minute = tm.tm_min; eft.second = tm.tm_sec; eft.nanosecond = 0; } else { pr_err("%s: Invalid EFI RTC value: write of %lx to EFI RTC failed\n", __func__, nowtime); return -1; } status = efi.set_time(&eft); if (status != EFI_SUCCESS) { pr_err("Oops: efitime: can't write time!\n"); return -1; } return 0; } void efi_get_time(struct timespec *now) { efi_status_t status; efi_time_t eft; efi_time_cap_t cap; status = efi.get_time(&eft, &cap); if (status != EFI_SUCCESS) pr_err("Oops: efitime: can't read time!\n"); now->tv_sec = mktime(eft.year, eft.month, eft.day, eft.hour, eft.minute, eft.second); now->tv_nsec = 0; } /* * 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); } int __init efi_memblock_x86_reserve_range(void) { struct efi_info *e = &boot_params.efi_info; unsigned long pmap; #ifdef CONFIG_X86_32 /* Can't handle data above 4GB at this time */ if (e->efi_memmap_hi) { pr_err("Memory map is above 4GB, disabling EFI.\n"); return -EINVAL; } pmap = e->efi_memmap; #else pmap = (e->efi_memmap | ((__u64)e->efi_memmap_hi << 32)); #endif memmap.phys_map = (void *)pmap; memmap.nr_map = e->efi_memmap_size / e->efi_memdesc_size; memmap.desc_size = e->efi_memdesc_size; memmap.desc_version = e->efi_memdesc_version; memblock_reserve(pmap, memmap.nr_map * memmap.desc_size); efi.memmap = &memmap; return 0; } static void __init print_efi_memmap(void) { #ifdef EFI_DEBUG 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; pr_info("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_unmap_memmap(void) { clear_bit(EFI_MEMMAP, &efi.flags); if (memmap.map) { early_iounmap(memmap.map, memmap.nr_map * memmap.desc_size); memmap.map = NULL; } } static int __init efi_systab_init(void *phys) { if (efi_enabled(EFI_64BIT)) { efi_system_table_64_t *systab64; struct efi_setup_data *data = NULL; u64 tmp = 0; if (efi_setup) { data = early_memremap(efi_setup, sizeof(*data)); if (!data) return -ENOMEM; } systab64 = early_ioremap((unsigned long)phys, sizeof(*systab64)); if (systab64 == NULL) { pr_err("Couldn't map the system table!\n"); if (data) early_iounmap(data, sizeof(*data)); return -ENOMEM; } efi_systab.hdr = systab64->hdr; efi_systab.fw_vendor = data ? (unsigned long)data->fw_vendor : systab64->fw_vendor; tmp |= data ? data->fw_vendor : systab64->fw_vendor; efi_systab.fw_revision = systab64->fw_revision; efi_systab.con_in_handle = systab64->con_in_handle; tmp |= systab64->con_in_handle; efi_systab.con_in = systab64->con_in; tmp |= systab64->con_in; efi_systab.con_out_handle = systab64->con_out_handle; tmp |= systab64->con_out_handle; efi_systab.con_out = systab64->con_out; tmp |= systab64->con_out; efi_systab.stderr_handle = systab64->stderr_handle; tmp |= systab64->stderr_handle; efi_systab.stderr = systab64->stderr; tmp |= systab64->stderr; efi_systab.runtime = data ? (void *)(unsigned long)data->runtime : (void *)(unsigned long)systab64->runtime; tmp |= data ? data->runtime : systab64->runtime; efi_systab.boottime = (void *)(unsigned long)systab64->boottime; tmp |= systab64->boottime; efi_systab.nr_tables = systab64->nr_tables; efi_systab.tables = data ? (unsigned long)data->tables : systab64->tables; tmp |= data ? data->tables : systab64->tables; early_iounmap(systab64, sizeof(*systab64)); if (data) early_iounmap(data, sizeof(*data)); #ifdef CONFIG_X86_32 if (tmp >> 32) { pr_err("EFI data located above 4GB, disabling EFI.\n"); return -EINVAL; } #endif } else { efi_system_table_32_t *systab32; systab32 = early_ioremap((unsigned long)phys, sizeof(*systab32)); if (systab32 == NULL) { pr_err("Couldn't map the system table!\n"); return -ENOMEM; } efi_systab.hdr = systab32->hdr; efi_systab.fw_vendor = systab32->fw_vendor; efi_systab.fw_revision = systab32->fw_revision; efi_systab.con_in_handle = systab32->con_in_handle; efi_systab.con_in = systab32->con_in; efi_systab.con_out_handle = systab32->con_out_handle; efi_systab.con_out = systab32->con_out; efi_systab.stderr_handle = systab32->stderr_handle; efi_systab.stderr = systab32->stderr; efi_systab.runtime = (void *)(unsigned long)systab32->runtime; efi_systab.boottime = (void *)(unsigned long)systab32->boottime; efi_systab.nr_tables = systab32->nr_tables; efi_systab.tables = systab32->tables; early_iounmap(systab32, sizeof(*systab32)); } efi.systab = &efi_systab; /* * Verify the EFI Table */ if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) { pr_err("System table signature incorrect!\n"); return -EINVAL; } if ((efi.systab->hdr.revision >> 16) == 0) pr_err("Warning: 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, &efi.flags); return 0; } static int __init efi_runtime_init32(void) { efi_runtime_services_32_t *runtime; runtime = early_ioremap((unsigned long)efi.systab->runtime, sizeof(efi_runtime_services_32_t)); if (!runtime) { pr_err("Could not map the runtime service table!\n"); return -ENOMEM; } /* * We will only need *early* access to the following two * EFI runtime services before set_virtual_address_map * is invoked. */ efi_phys.set_virtual_address_map = (efi_set_virtual_address_map_t *) (unsigned long)runtime->set_virtual_address_map; early_iounmap(runtime, sizeof(efi_runtime_services_32_t)); return 0; } static int __init efi_runtime_init64(void) { efi_runtime_services_64_t *runtime; runtime = early_ioremap((unsigned long)efi.systab->runtime, sizeof(efi_runtime_services_64_t)); if (!runtime) { pr_err("Could not map the runtime service table!\n"); return -ENOMEM; } /* * We will only need *early* access to the following two * EFI runtime services before set_virtual_address_map * is invoked. */ efi_phys.set_virtual_address_map = (efi_set_virtual_address_map_t *) (unsigned long)runtime->set_virtual_address_map; early_iounmap(runtime, sizeof(efi_runtime_services_64_t)); return 0; } static int __init efi_runtime_init(void) { int rv; /* * 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. */ if (efi_enabled(EFI_64BIT)) rv = efi_runtime_init64(); else rv = efi_runtime_init32(); if (rv) return rv; set_bit(EFI_RUNTIME_SERVICES, &efi.flags); return 0; } static int __init efi_memmap_init(void) { /* Map the EFI memory map */ memmap.map = early_ioremap((unsigned long)memmap.phys_map, memmap.nr_map * memmap.desc_size); if (memmap.map == NULL) { pr_err("Could not map the memory map!\n"); return -ENOMEM; } memmap.map_end = memmap.map + (memmap.nr_map * memmap.desc_size); if (add_efi_memmap) do_add_efi_memmap(); set_bit(EFI_MEMMAP, &efi.flags); return 0; } void __init efi_init(void) { efi_char16_t *c16; char vendor[100] = "unknown"; int i = 0; void *tmp; #ifdef CONFIG_X86_32 if (boot_params.efi_info.efi_systab_hi || boot_params.efi_info.efi_memmap_hi) { pr_info("Table located above 4GB, disabling EFI.\n"); return; } 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 if (efi_systab_init(efi_phys.systab)) return; set_bit(EFI_SYSTEM_TABLES, &efi.flags); efi.config_table = (unsigned long)efi.systab->tables; efi.fw_vendor = (unsigned long)efi.systab->fw_vendor; efi.runtime = (unsigned long)efi.systab->runtime; /* * 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 pr_err("Could not map the firmware vendor!\n"); early_iounmap(tmp, 2); pr_info("EFI v%u.%.02u by %s\n", efi.systab->hdr.revision >> 16, efi.systab->hdr.revision & 0xffff, vendor); if (efi_reuse_config(efi.systab->tables, efi.systab->nr_tables)) return; if (efi_config_init(arch_tables)) return; /* * Note: We currently don't support runtime services on an EFI * that doesn't match the kernel 32/64-bit mode. */ if (!efi_runtime_supported()) pr_info("No EFI runtime due to 32/64-bit mismatch with kernel\n"); else { if (disable_runtime || efi_runtime_init()) return; } if (efi_memmap_init()) return; set_bit(EFI_MEMMAP, &efi.flags); print_efi_memmap(); } void __init efi_late_init(void) { efi_bgrt_init(); } 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); } 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); } } void efi_memory_uc(u64 addr, unsigned long size) { unsigned long page_shift = 1UL << EFI_PAGE_SHIFT; u64 npages; npages = round_up(size, page_shift) / page_shift; memrange_efi_to_native(&addr, &npages); set_memory_uc(addr, npages); } void __init old_map_region(efi_memory_desc_t *md) { u64 start_pfn, end_pfn, end; unsigned long size; void *va; start_pfn = PFN_DOWN(md->phys_addr); size = md->num_pages << PAGE_SHIFT; end = md->phys_addr + size; end_pfn = PFN_UP(end); if (pfn_range_is_mapped(start_pfn, end_pfn)) { va = __va(md->phys_addr); if (!(md->attribute & EFI_MEMORY_WB)) efi_memory_uc((u64)(unsigned long)va, size); } else va = efi_ioremap(md->phys_addr, size, md->type, md->attribute); md->virt_addr = (u64) (unsigned long) va; if (!va) pr_err("ioremap of 0x%llX failed!\n", (unsigned long long)md->phys_addr); } static void native_runtime_setup(void) { 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.query_variable_info = virt_efi_query_variable_info; efi.update_capsule = virt_efi_update_capsule; efi.query_capsule_caps = virt_efi_query_capsule_caps; } /* Merge contiguous regions of the same type and attribute */ static void __init efi_merge_regions(void) { void *p; efi_memory_desc_t *md, *prev_md = NULL; 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; } } static void __init get_systab_virt_addr(efi_memory_desc_t *md) { unsigned long size; u64 end, systab; size = md->num_pages << EFI_PAGE_SHIFT; end = md->phys_addr + size; 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; } } static void __init save_runtime_map(void) { #ifdef CONFIG_KEXEC efi_memory_desc_t *md; void *tmp, *p, *q = NULL; int count = 0; if (efi_enabled(EFI_OLD_MEMMAP)) return; 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; tmp = krealloc(q, (count + 1) * memmap.desc_size, GFP_KERNEL); if (!tmp) goto out; q = tmp; memcpy(q + count * memmap.desc_size, md, memmap.desc_size); count++; } efi_runtime_map_setup(q, count, memmap.desc_size); return; out: kfree(q); pr_err("Error saving runtime map, efi runtime on kexec non-functional!!\n"); #endif } static void *realloc_pages(void *old_memmap, int old_shift) { void *ret; ret = (void *)__get_free_pages(GFP_KERNEL, old_shift + 1); if (!ret) goto out; /* * A first-time allocation doesn't have anything to copy. */ if (!old_memmap) return ret; memcpy(ret, old_memmap, PAGE_SIZE << old_shift); out: free_pages((unsigned long)old_memmap, old_shift); return ret; } /* * Map the efi memory ranges of the runtime services and update new_mmap with * virtual addresses. */ static void * __init efi_map_regions(int *count, int *pg_shift) { void *p, *new_memmap = NULL; unsigned long left = 0; efi_memory_desc_t *md; for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) { md = p; if (!(md->attribute & EFI_MEMORY_RUNTIME)) { #ifdef CONFIG_X86_64 if (md->type != EFI_BOOT_SERVICES_CODE && md->type != EFI_BOOT_SERVICES_DATA) #endif continue; } efi_map_region(md); get_systab_virt_addr(md); if (left < memmap.desc_size) { new_memmap = realloc_pages(new_memmap, *pg_shift); if (!new_memmap) return NULL; left += PAGE_SIZE << *pg_shift; (*pg_shift)++; } memcpy(new_memmap + (*count * memmap.desc_size), md, memmap.desc_size); left -= memmap.desc_size; (*count)++; } return new_memmap; } static void __init kexec_enter_virtual_mode(void) { #ifdef CONFIG_KEXEC efi_memory_desc_t *md; void *p; efi.systab = NULL; /* * We don't do virtual mode, since we don't do runtime services, on * non-native EFI */ if (!efi_is_native()) { efi_unmap_memmap(); return; } /* * Map efi regions which were passed via setup_data. The virt_addr is a * fixed addr which was used in first kernel of a kexec boot. */ for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) { md = p; efi_map_region_fixed(md); /* FIXME: add error handling */ get_systab_virt_addr(md); } save_runtime_map(); BUG_ON(!efi.systab); efi_sync_low_kernel_mappings(); /* * 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; native_runtime_setup(); efi.set_virtual_address_map = NULL; if (efi_enabled(EFI_OLD_MEMMAP) && (__supported_pte_mask & _PAGE_NX)) runtime_code_page_mkexec(); /* clean DUMMY object */ efi_delete_dummy_variable(); #endif } /* * This function will switch the EFI runtime services to virtual mode. * Essentially, we look through the EFI memmap and map every region that * has the runtime attribute bit set in its memory descriptor into the * ->trampoline_pgd page table using a top-down VA allocation scheme. * * The old method which used to update that memory descriptor with the * virtual address obtained from ioremap() is still supported when the * kernel is booted with efi=old_map on its command line. Same old * method enabled the runtime services to be called without having to * thunk back into physical mode for every invocation. * * The new method does a pagetable switch in a preemption-safe manner * so that we're in a different address space when calling a runtime * function. For function arguments passing we do copy the PGDs of the * kernel page table into ->trampoline_pgd prior to each call. * * Specially for kexec boot, efi runtime maps in previous kernel should * be passed in via setup_data. In that case runtime ranges will be mapped * to the same virtual addresses as the first kernel, see * kexec_enter_virtual_mode(). */ static void __init __efi_enter_virtual_mode(void) { int count = 0, pg_shift = 0; void *new_memmap = NULL; efi_status_t status; efi.systab = NULL; efi_merge_regions(); new_memmap = efi_map_regions(&count, &pg_shift); if (!new_memmap) { pr_err("Error reallocating memory, EFI runtime non-functional!\n"); return; } save_runtime_map(); BUG_ON(!efi.systab); if (efi_setup_page_tables(__pa(new_memmap), 1 << pg_shift)) return; efi_sync_low_kernel_mappings(); efi_dump_pagetable(); if (efi_is_native()) { status = phys_efi_set_virtual_address_map( memmap.desc_size * count, memmap.desc_size, memmap.desc_version, (efi_memory_desc_t *)__pa(new_memmap)); } else { status = efi_thunk_set_virtual_address_map( efi_phys.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) { pr_alert("Unable to switch EFI into virtual mode (status=%lx)!\n", status); panic("EFI call to SetVirtualAddressMap() failed!"); } /* * 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; if (efi_is_native()) native_runtime_setup(); else efi_thunk_runtime_setup(); efi.set_virtual_address_map = NULL; efi_runtime_mkexec(); /* * We mapped the descriptor array into the EFI pagetable above but we're * not unmapping it here. Here's why: * * We're copying select PGDs from the kernel page table to the EFI page * table and when we do so and make changes to those PGDs like unmapping * stuff from them, those changes appear in the kernel page table and we * go boom. * * From setup_real_mode(): * * ... * trampoline_pgd[0] = init_level4_pgt[pgd_index(__PAGE_OFFSET)].pgd; * * In this particular case, our allocation is in PGD 0 of the EFI page * table but we've copied that PGD from PGD[272] of the EFI page table: * * pgd_index(__PAGE_OFFSET = 0xffff880000000000) = 272 * * where the direct memory mapping in kernel space is. * * new_memmap's VA comes from that direct mapping and thus clearing it, * it would get cleared in the kernel page table too. * * efi_cleanup_page_tables(__pa(new_memmap), 1 << pg_shift); */ free_pages((unsigned long)new_memmap, pg_shift); /* clean DUMMY object */ efi_delete_dummy_variable(); } void __init efi_enter_virtual_mode(void) { if (efi_setup) kexec_enter_virtual_mode(); else __efi_enter_virtual_mode(); } /* * 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; } static int __init parse_efi_cmdline(char *str) { if (*str == '=') str++; if (!strncmp(str, "old_map", 7)) set_bit(EFI_OLD_MEMMAP, &efi.flags); return 0; } early_param("efi", parse_efi_cmdline);