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Diffstat (limited to 'kernel/arch/x86/platform/efi/efi.c')
-rw-r--r--kernel/arch/x86/platform/efi/efi.c956
1 files changed, 956 insertions, 0 deletions
diff --git a/kernel/arch/x86/platform/efi/efi.c b/kernel/arch/x86/platform/efi/efi.c
new file mode 100644
index 000000000..02744df57
--- /dev/null
+++ b/kernel/arch/x86/platform/efi/efi.c
@@ -0,0 +1,956 @@
+/*
+ * 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 <drummond@valinux.com>
+ * Copyright (C) 1999-2002 Hewlett-Packard Co.
+ * David Mosberger-Tang <davidm@hpl.hp.com>
+ * Stephane Eranian <eranian@hpl.hp.com>
+ * Copyright (C) 2005-2008 Intel Co.
+ * Fenghua Yu <fenghua.yu@intel.com>
+ * Bibo Mao <bibo.mao@intel.com>
+ * Chandramouli Narayanan <mouli@linux.intel.com>
+ * Huang Ying <ying.huang@intel.com>
+ * Copyright (C) 2013 SuSE Labs
+ * Borislav Petkov <bp@suse.de> - 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: <goutham.rao@intel.com>
+ * Skip non-WB memory and ignore empty memory ranges.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/efi.h>
+#include <linux/efi-bgrt.h>
+#include <linux/export.h>
+#include <linux/bootmem.h>
+#include <linux/slab.h>
+#include <linux/memblock.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+#include <linux/time.h>
+#include <linux/io.h>
+#include <linux/reboot.h>
+#include <linux/bcd.h>
+
+#include <asm/setup.h>
+#include <asm/efi.h>
+#include <asm/time.h>
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+#include <asm/x86_init.h>
+#include <asm/rtc.h>
+#include <asm/uv/uv.h>
+
+#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 int add_efi_memmap __initdata;
+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 __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;
+ unsigned long flags;
+ pgd_t *save_pgd;
+
+ save_pgd = efi_call_phys_prolog();
+
+ /* Disable interrupts around EFI calls: */
+ local_irq_save(flags);
+ status = efi_call_phys(efi_phys.set_virtual_address_map,
+ memory_map_size, descriptor_size,
+ descriptor_version, virtual_map);
+ local_irq_restore(flags);
+
+ efi_call_phys_epilog(save_pgd);
+
+ return status;
+}
+
+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;
+
+ if (efi_enabled(EFI_PARAVIRT))
+ return 0;
+
+#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++) {
+ char buf[64];
+
+ md = p;
+ pr_info("mem%02u: %s range=[0x%016llx-0x%016llx) (%lluMB)\n",
+ i, efi_md_typeattr_format(buf, sizeof(buf), md),
+ 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_memunmap(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_memremap((unsigned long)phys,
+ sizeof(*systab64));
+ if (systab64 == NULL) {
+ pr_err("Couldn't map the system table!\n");
+ if (data)
+ early_memunmap(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_memunmap(systab64, sizeof(*systab64));
+ if (data)
+ early_memunmap(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_memremap((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_memunmap(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_memremap((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 SetVirtualAddressMap
+ * EFI runtime service. All other runtime services will be called
+ * via the virtual mapping.
+ */
+ efi_phys.set_virtual_address_map =
+ (efi_set_virtual_address_map_t *)
+ (unsigned long)runtime->set_virtual_address_map;
+ early_memunmap(runtime, sizeof(efi_runtime_services_32_t));
+
+ return 0;
+}
+
+static int __init efi_runtime_init64(void)
+{
+ efi_runtime_services_64_t *runtime;
+
+ runtime = early_memremap((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 SetVirtualAddressMap
+ * EFI runtime service. All other runtime services will be called
+ * via the virtual mapping.
+ */
+ efi_phys.set_virtual_address_map =
+ (efi_set_virtual_address_map_t *)
+ (unsigned long)runtime->set_virtual_address_map;
+ early_memunmap(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.
+ *
+ * When EFI_PARAVIRT is in force then we could not map runtime
+ * service memory region because we do not have direct access to it.
+ * However, runtime services are available through proxy functions
+ * (e.g. in case of Xen dom0 EFI implementation they call special
+ * hypercall which executes relevant EFI functions) and that is why
+ * they are always enabled.
+ */
+
+ if (!efi_enabled(EFI_PARAVIRT)) {
+ 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)
+{
+ if (efi_enabled(EFI_PARAVIRT))
+ return 0;
+
+ /* Map the EFI memory map */
+ memmap.map = early_memremap((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;
+
+ 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_memremap(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_memunmap(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 (efi_runtime_disabled() || efi_runtime_init())
+ return;
+ }
+ if (efi_memmap_init())
+ return;
+
+ if (efi_enabled(EFI_DBG))
+ 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 __init 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);
+}
+
+/* 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();
+ clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
+ 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;
+
+ efi_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");
+ clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
+ return;
+ }
+
+ save_runtime_map();
+
+ BUG_ON(!efi.systab);
+
+ if (efi_setup_page_tables(__pa(new_memmap), 1 << pg_shift)) {
+ clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
+ 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())
+ efi_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_enabled(EFI_PARAVIRT))
+ return;
+
+ 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;
+
+ 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->attribute;
+ }
+ return 0;
+}
+
+static int __init arch_parse_efi_cmdline(char *str)
+{
+ if (parse_option_str(str, "old_map"))
+ set_bit(EFI_OLD_MEMMAP, &efi.flags);
+ if (parse_option_str(str, "debug"))
+ set_bit(EFI_DBG, &efi.flags);
+
+ return 0;
+}
+early_param("efi", arch_parse_efi_cmdline);