Merge branch 'x86-efi-kexec-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 EFI changes from Ingo Molnar:
 "This consists of two main parts:

   - New static EFI runtime services virtual mapping layout which is
     groundwork for kexec support on EFI (Borislav Petkov)

   - EFI kexec support itself (Dave Young)"

* 'x86-efi-kexec-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  x86/efi: parse_efi_setup() build fix
  x86: ksysfs.c build fix
  x86/efi: Delete superfluous global variables
  x86: Reserve setup_data ranges late after parsing memmap cmdline
  x86: Export x86 boot_params to sysfs
  x86: Add xloadflags bit for EFI runtime support on kexec
  x86/efi: Pass necessary EFI data for kexec via setup_data
  efi: Export EFI runtime memory mapping to sysfs
  efi: Export more EFI table variables to sysfs
  x86/efi: Cleanup efi_enter_virtual_mode() function
  x86/efi: Fix off-by-one bug in EFI Boot Services reservation
  x86/efi: Add a wrapper function efi_map_region_fixed()
  x86/efi: Remove unused variables in __map_region()
  x86/efi: Check krealloc return value
  x86/efi: Runtime services virtual mapping
  x86/mm/cpa: Map in an arbitrary pgd
  x86/mm/pageattr: Add last levels of error path
  x86/mm/pageattr: Add a PUD error unwinding path
  x86/mm/pageattr: Add a PTE pagetable populating function
  x86/mm/pageattr: Add a PMD pagetable populating function
  ...

4 files changed, 465 insertions, 76 deletions

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index cceb813..d62ec87 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -12,6 +12,8 @@
  *	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
@@ -51,7 +53,7 @@
 #include <asm/x86_init.h>
 #include <asm/rtc.h>
 
-#define EFI_DEBUG	1
+#define EFI_DEBUG
 
 #define EFI_MIN_RESERVE 5120
 
@@ -74,6 +76,8 @@ static __initdata efi_config_table_type_t arch_tables[] = {
 	{NULL_GUID, NULL, NULL},
 };
 
+u64 efi_setup;		/* efi setup_data physical address */
+
 /*
  * Returns 1 if 'facility' is enabled, 0 otherwise.
  */
@@ -110,7 +114,6 @@ static int __init setup_storage_paranoia(char *arg)
 }
 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;
@@ -398,9 +401,9 @@ int __init efi_memblock_x86_reserve_range(void)
 	return 0;
 }
 
-#if EFI_DEBUG
 static void __init print_efi_memmap(void)
 {
+#ifdef EFI_DEBUG
 	efi_memory_desc_t *md;
 	void *p;
 	int i;
@@ -415,8 +418,8 @@ static void __init print_efi_memmap(void)
 			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)
 {
@@ -436,7 +439,7 @@ void __init efi_reserve_boot_services(void)
 		 * - Not within any part of the kernel
 		 * - Not the bios reserved area
 		*/
-		if ((start+size >= __pa_symbol(_text)
+		if ((start + size > __pa_symbol(_text)
 				&& start <= __pa_symbol(_end)) ||
 			!e820_all_mapped(start, start+size, E820_RAM) ||
 			memblock_is_region_reserved(start, size)) {
@@ -489,18 +492,27 @@ 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 = systab64->fw_vendor;
-		tmp |= systab64->fw_vendor;
+		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;
@@ -514,15 +526,20 @@ static int __init efi_systab_init(void *phys)
 		tmp |= systab64->stderr_handle;
 		efi_systab.stderr = systab64->stderr;
 		tmp |= systab64->stderr;
-		efi_systab.runtime = (void *)(unsigned long)systab64->runtime;
-		tmp |= systab64->runtime;
+		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 = systab64->tables;
-		tmp |= systab64->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");
@@ -626,6 +643,62 @@ static int __init efi_memmap_init(void)
 	return 0;
 }
 
+/*
+ * 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.
+ */
+static int __init efi_reuse_config(u64 tables, int nr_tables)
+{
+	int i, sz, ret = 0;
+	void *p, *tablep;
+	struct efi_setup_data *data;
+
+	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 < efi.systab->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_iounmap(tablep, nr_tables * sz);
+
+out_memremap:
+	early_iounmap(data, sizeof(*data));
+out:
+	return ret;
+}
+
 void __init efi_init(void)
 {
 	efi_char16_t *c16;
@@ -651,6 +724,10 @@ void __init efi_init(void)
 
 	set_bit(EFI_SYSTEM_TABLES, &x86_efi_facility);
 
+	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
 	 */
@@ -667,6 +744,9 @@ void __init efi_init(void)
 		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;
 
@@ -684,15 +764,12 @@ void __init efi_init(void)
 			return;
 		set_bit(EFI_RUNTIME_SERVICES, &x86_efi_facility);
 	}
-
 	if (efi_memmap_init())
 		return;
 
 	set_bit(EFI_MEMMAP, &x86_efi_facility);
 
-#if EFI_DEBUG
 	print_efi_memmap();
-#endif
 }
 
 void __init efi_late_init(void)
@@ -741,36 +818,38 @@ void efi_memory_uc(u64 addr, unsigned long size)
 	set_memory_uc(addr, npages);
 }
 
-/*
- * 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)
+void __init old_map_region(efi_memory_desc_t *md)
 {
-	efi_memory_desc_t *md, *prev_md = NULL;
-	efi_status_t status;
+	u64 start_pfn, end_pfn, end;
 	unsigned long size;
-	u64 end, systab, start_pfn, end_pfn;
-	void *p, *va, *new_memmap = NULL;
-	int count = 0;
+	void *va;
 
-	efi.systab = NULL;
+	start_pfn = PFN_DOWN(md->phys_addr);
+	size	  = md->num_pages << PAGE_SHIFT;
+	end	  = md->phys_addr + size;
+	end_pfn   = PFN_UP(end);
 
-	/*
-	 * We don't do virtual mode, since we don't do runtime services, on
-	 * non-native EFI
-	 */
+	if (pfn_range_is_mapped(start_pfn, end_pfn)) {
+		va = __va(md->phys_addr);
 
-	if (!efi_is_native()) {
-		efi_unmap_memmap();
-		return;
-	}
+		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;
 
-	/* 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;
@@ -796,6 +875,77 @@ void __init efi_enter_virtual_mode(void)
 		}
 		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 int __init save_runtime_map(void)
+{
+	efi_memory_desc_t *md;
+	void *tmp, *p, *q = NULL;
+	int count = 0;
+
+	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 0;
+out:
+	kfree(q);
+	return -ENOMEM;
+}
+
+/*
+ * 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.
+ */
+static void __init efi_map_regions_fixed(void)
+{
+	void *p;
+	efi_memory_desc_t *md;
+
+	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);
+	}
+
+}
+
+/*
+ * Map efi memory ranges for runtime serivce and update new_memmap with virtual
+ * addresses.
+ */
+static void * __init efi_map_regions(int *count)
+{
+	efi_memory_desc_t *md;
+	void *p, *tmp, *new_memmap = NULL;
 
 	for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 		md = p;
@@ -807,53 +957,95 @@ void __init efi_enter_virtual_mode(void)
 				continue;
 		}
 
-		size = md->num_pages << EFI_PAGE_SHIFT;
-		end = md->phys_addr + size;
+		efi_map_region(md);
+		get_systab_virt_addr(md);
 
-		start_pfn = PFN_DOWN(md->phys_addr);
-		end_pfn = PFN_UP(end);
-		if (pfn_range_is_mapped(start_pfn, end_pfn)) {
-			va = __va(md->phys_addr);
+		tmp = krealloc(new_memmap, (*count + 1) * memmap.desc_size,
+			       GFP_KERNEL);
+		if (!tmp)
+			goto out;
+		new_memmap = tmp;
+		memcpy(new_memmap + (*count * memmap.desc_size), md,
+		       memmap.desc_size);
+		(*count)++;
+	}
 
-			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);
+	return new_memmap;
+out:
+	kfree(new_memmap);
+	return NULL;
+}
+
+/*
+ * 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.
+ */
+void __init efi_enter_virtual_mode(void)
+{
+	efi_status_t status;
+	void *new_memmap = NULL;
+	int err, count = 0;
 
-		md->virt_addr = (u64) (unsigned long) va;
+	efi.systab = NULL;
 
-		if (!va) {
-			pr_err("ioremap of 0x%llX failed!\n",
-			       (unsigned long long)md->phys_addr);
-			continue;
-		}
+	/*
+	 * 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;
+	}
 
-		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;
+	if (efi_setup) {
+		efi_map_regions_fixed();
+	} else {
+		efi_merge_regions();
+		new_memmap = efi_map_regions(&count);
+		if (!new_memmap) {
+			pr_err("Error reallocating memory, EFI runtime non-functional!\n");
+			return;
 		}
-		new_memmap = krealloc(new_memmap,
-				      (count + 1) * memmap.desc_size,
-				      GFP_KERNEL);
-		memcpy(new_memmap + (count * memmap.desc_size), md,
-		       memmap.desc_size);
-		count++;
 	}
 
+	err = save_runtime_map();
+	if (err)
+		pr_err("Error saving runtime map, efi runtime on kexec non-functional!!\n");
+
 	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));
+	efi_setup_page_tables();
+	efi_sync_low_kernel_mappings();
 
-	if (status != EFI_SUCCESS) {
-		pr_alert("Unable to switch EFI into virtual mode "
-			 "(status=%lx)!\n", status);
-		panic("EFI call to SetVirtualAddressMap() failed!");
+	if (!efi_setup) {
+		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) {
+			pr_alert("Unable to switch EFI into virtual mode (status=%lx)!\n",
+				 status);
+			panic("EFI call to SetVirtualAddressMap() failed!");
+		}
 	}
 
 	/*
@@ -876,7 +1068,8 @@ void __init efi_enter_virtual_mode(void)
 	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)
+
+	if (efi_enabled(EFI_OLD_MEMMAP) && (__supported_pte_mask & _PAGE_NX))
 		runtime_code_page_mkexec();
 
 	kfree(new_memmap);
@@ -1006,3 +1199,15 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
 	return EFI_SUCCESS;
 }
 EXPORT_SYMBOL_GPL(efi_query_variable_store);
+
+static int __init parse_efi_cmdline(char *str)
+{
+	if (*str == '=')
+		str++;
+
+	if (!strncmp(str, "old_map", 7))
+		set_bit(EFI_OLD_MEMMAP, &x86_efi_facility);
+
+	return 0;
+}
+early_param("efi", parse_efi_cmdline);
diff --git a/arch/x86/platform/efi/efi_32.c b/arch/x86/platform/efi/efi_32.c
index 40e4469..249b183 100644
--- a/arch/x86/platform/efi/efi_32.c
+++ b/arch/x86/platform/efi/efi_32.c
@@ -37,9 +37,19 @@
  * claim EFI runtime service handler exclusively and to duplicate a memory in
  * low memory space say 0 - 3G.
  */
-
 static unsigned long efi_rt_eflags;
 
+void efi_sync_low_kernel_mappings(void) {}
+void efi_setup_page_tables(void) {}
+
+void __init efi_map_region(efi_memory_desc_t *md)
+{
+	old_map_region(md);
+}
+
+void __init efi_map_region_fixed(efi_memory_desc_t *md) {}
+void __init parse_efi_setup(u64 phys_addr, u32 data_len) {}
+
 void efi_call_phys_prelog(void)
 {
 	struct desc_ptr gdt_descr;
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 39a0e7f..6284f15 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -38,10 +38,28 @@
 #include <asm/efi.h>
 #include <asm/cacheflush.h>
 #include <asm/fixmap.h>
+#include <asm/realmode.h>
 
 static pgd_t *save_pgd __initdata;
 static unsigned long efi_flags __initdata;
 
+/*
+ * We allocate runtime services regions bottom-up, starting from -4G, i.e.
+ * 0xffff_ffff_0000_0000 and limit EFI VA mapping space to 64G.
+ */
+static u64 efi_va	= -4 * (1UL << 30);
+#define EFI_VA_END	(-68 * (1UL << 30))
+
+/*
+ * Scratch space used for switching the pagetable in the EFI stub
+ */
+struct efi_scratch {
+	u64 r15;
+	u64 prev_cr3;
+	pgd_t *efi_pgt;
+	bool use_pgd;
+};
+
 static void __init early_code_mapping_set_exec(int executable)
 {
 	efi_memory_desc_t *md;
@@ -65,6 +83,9 @@ void __init efi_call_phys_prelog(void)
 	int pgd;
 	int n_pgds;
 
+	if (!efi_enabled(EFI_OLD_MEMMAP))
+		return;
+
 	early_code_mapping_set_exec(1);
 	local_irq_save(efi_flags);
 
@@ -86,6 +107,10 @@ void __init efi_call_phys_epilog(void)
 	 */
 	int pgd;
 	int n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT) , PGDIR_SIZE);
+
+	if (!efi_enabled(EFI_OLD_MEMMAP))
+		return;
+
 	for (pgd = 0; pgd < n_pgds; pgd++)
 		set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), save_pgd[pgd]);
 	kfree(save_pgd);
@@ -94,6 +119,96 @@ void __init efi_call_phys_epilog(void)
 	early_code_mapping_set_exec(0);
 }
 
+/*
+ * Add low kernel mappings for passing arguments to EFI functions.
+ */
+void efi_sync_low_kernel_mappings(void)
+{
+	unsigned num_pgds;
+	pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd);
+
+	if (efi_enabled(EFI_OLD_MEMMAP))
+		return;
+
+	num_pgds = pgd_index(MODULES_END - 1) - pgd_index(PAGE_OFFSET);
+
+	memcpy(pgd + pgd_index(PAGE_OFFSET),
+		init_mm.pgd + pgd_index(PAGE_OFFSET),
+		sizeof(pgd_t) * num_pgds);
+}
+
+void efi_setup_page_tables(void)
+{
+	efi_scratch.efi_pgt = (pgd_t *)(unsigned long)real_mode_header->trampoline_pgd;
+
+	if (!efi_enabled(EFI_OLD_MEMMAP))
+		efi_scratch.use_pgd = true;
+}
+
+static void __init __map_region(efi_memory_desc_t *md, u64 va)
+{
+	pgd_t *pgd = (pgd_t *)__va(real_mode_header->trampoline_pgd);
+	unsigned long pf = 0;
+
+	if (!(md->attribute & EFI_MEMORY_WB))
+		pf |= _PAGE_PCD;
+
+	if (kernel_map_pages_in_pgd(pgd, md->phys_addr, va, md->num_pages, pf))
+		pr_warn("Error mapping PA 0x%llx -> VA 0x%llx!\n",
+			   md->phys_addr, va);
+}
+
+void __init efi_map_region(efi_memory_desc_t *md)
+{
+	unsigned long size = md->num_pages << PAGE_SHIFT;
+	u64 pa = md->phys_addr;
+
+	if (efi_enabled(EFI_OLD_MEMMAP))
+		return old_map_region(md);
+
+	/*
+	 * Make sure the 1:1 mappings are present as a catch-all for b0rked
+	 * firmware which doesn't update all internal pointers after switching
+	 * to virtual mode and would otherwise crap on us.
+	 */
+	__map_region(md, md->phys_addr);
+
+	efi_va -= size;
+
+	/* Is PA 2M-aligned? */
+	if (!(pa & (PMD_SIZE - 1))) {
+		efi_va &= PMD_MASK;
+	} else {
+		u64 pa_offset = pa & (PMD_SIZE - 1);
+		u64 prev_va = efi_va;
+
+		/* get us the same offset within this 2M page */
+		efi_va = (efi_va & PMD_MASK) + pa_offset;
+
+		if (efi_va > prev_va)
+			efi_va -= PMD_SIZE;
+	}
+
+	if (efi_va < EFI_VA_END) {
+		pr_warn(FW_WARN "VA address range overflow!\n");
+		return;
+	}
+
+	/* Do the VA map */
+	__map_region(md, efi_va);
+	md->virt_addr = efi_va;
+}
+
+/*
+ * kexec kernel will use efi_map_region_fixed to map efi runtime memory ranges.
+ * md->virt_addr is the original virtual address which had been mapped in kexec
+ * 1st kernel.
+ */
+void __init efi_map_region_fixed(efi_memory_desc_t *md)
+{
+	__map_region(md, md->virt_addr);
+}
+
 void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
 				 u32 type, u64 attribute)
 {
@@ -113,3 +228,8 @@ void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
 
 	return (void __iomem *)__va(phys_addr);
 }
+
+void __init parse_efi_setup(u64 phys_addr, u32 data_len)
+{
+	efi_setup = phys_addr + sizeof(struct setup_data);
+}
diff --git a/arch/x86/platform/efi/efi_stub_64.S b/arch/x86/platform/efi/efi_stub_64.S
index 4c07cca..88073b1 100644
--- a/arch/x86/platform/efi/efi_stub_64.S
+++ b/arch/x86/platform/efi/efi_stub_64.S
@@ -34,10 +34,47 @@
 	mov %rsi, %cr0;			\
 	mov (%rsp), %rsp
 
+	/* stolen from gcc */
+	.macro FLUSH_TLB_ALL
+	movq %r15, efi_scratch(%rip)
+	movq %r14, efi_scratch+8(%rip)
+	movq %cr4, %r15
+	movq %r15, %r14
+	andb $0x7f, %r14b
+	movq %r14, %cr4
+	movq %r15, %cr4
+	movq efi_scratch+8(%rip), %r14
+	movq efi_scratch(%rip), %r15
+	.endm
+
+	.macro SWITCH_PGT
+	cmpb $0, efi_scratch+24(%rip)
+	je 1f
+	movq %r15, efi_scratch(%rip)		# r15
+	# save previous CR3
+	movq %cr3, %r15
+	movq %r15, efi_scratch+8(%rip)		# prev_cr3
+	movq efi_scratch+16(%rip), %r15		# EFI pgt
+	movq %r15, %cr3
+	1:
+	.endm
+
+	.macro RESTORE_PGT
+	cmpb $0, efi_scratch+24(%rip)
+	je 2f
+	movq efi_scratch+8(%rip), %r15
+	movq %r15, %cr3
+	movq efi_scratch(%rip), %r15
+	FLUSH_TLB_ALL
+	2:
+	.endm
+
 ENTRY(efi_call0)
 	SAVE_XMM
 	subq $32, %rsp
+	SWITCH_PGT
 	call *%rdi
+	RESTORE_PGT
 	addq $32, %rsp
 	RESTORE_XMM
 	ret
@@ -47,7 +84,9 @@ ENTRY(efi_call1)
 	SAVE_XMM
 	subq $32, %rsp
 	mov  %rsi, %rcx
+	SWITCH_PGT
 	call *%rdi
+	RESTORE_PGT
 	addq $32, %rsp
 	RESTORE_XMM
 	ret
@@ -57,7 +96,9 @@ ENTRY(efi_call2)
 	SAVE_XMM
 	subq $32, %rsp
 	mov  %rsi, %rcx
+	SWITCH_PGT
 	call *%rdi
+	RESTORE_PGT
 	addq $32, %rsp
 	RESTORE_XMM
 	ret
@@ -68,7 +109,9 @@ ENTRY(efi_call3)
 	subq $32, %rsp
 	mov  %rcx, %r8
 	mov  %rsi, %rcx
+	SWITCH_PGT
 	call *%rdi
+	RESTORE_PGT
 	addq $32, %rsp
 	RESTORE_XMM
 	ret
@@ -80,7 +123,9 @@ ENTRY(efi_call4)
 	mov %r8, %r9
 	mov %rcx, %r8
 	mov %rsi, %rcx
+	SWITCH_PGT
 	call *%rdi
+	RESTORE_PGT
 	addq $32, %rsp
 	RESTORE_XMM
 	ret
@@ -93,7 +138,9 @@ ENTRY(efi_call5)
 	mov %r8, %r9
 	mov %rcx, %r8
 	mov %rsi, %rcx
+	SWITCH_PGT
 	call *%rdi
+	RESTORE_PGT
 	addq $48, %rsp
 	RESTORE_XMM
 	ret
@@ -109,8 +156,15 @@ ENTRY(efi_call6)
 	mov %r8, %r9
 	mov %rcx, %r8
 	mov %rsi, %rcx
+	SWITCH_PGT
 	call *%rdi
+	RESTORE_PGT
 	addq $48, %rsp
 	RESTORE_XMM
 	ret
 ENDPROC(efi_call6)
+
+	.data
+ENTRY(efi_scratch)
+	.fill 3,8,0
+	.byte 0