21 files changed, 1729 insertions, 141 deletions

diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index e1670d533f97..6394152f648f 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -87,6 +87,31 @@ config EFI_RUNTIME_WRAPPERS
 config EFI_ARMSTUB
 	bool
 
+config EFI_BOOTLOADER_CONTROL
+	tristate "EFI Bootloader Control"
+	depends on EFI_VARS
+	default n
+	---help---
+	  This module installs a reboot hook, such that if reboot() is
+	  invoked with a string argument NNN, "NNN" is copied to the
+	  "LoaderEntryOneShot" EFI variable, to be read by the
+	  bootloader. If the string matches one of the boot labels
+	  defined in its configuration, the bootloader will boot once
+	  to that label. The "LoaderEntryRebootReason" EFI variable is
+	  set with the reboot reason: "reboot" or "shutdown". The
+	  bootloader reads this reboot reason and takes particular
+	  action according to its policy.
+
+config EFI_CAPSULE_LOADER
+	tristate "EFI capsule loader"
+	depends on EFI
+	help
+	  This option exposes a loader interface "/dev/efi_capsule_loader" for
+	  users to load EFI capsules. This driver requires working runtime
+	  capsule support in the firmware, which many OEMs do not provide.
+
+	  Most users should say N.
+
 endmenu
 
 config UEFI_CPER
diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile
index 62e654f255f4..a219640f881f 100644
--- a/drivers/firmware/efi/Makefile
+++ b/drivers/firmware/efi/Makefile
@@ -9,7 +9,8 @@
 #
 KASAN_SANITIZE_runtime-wrappers.o	:= n
 
-obj-$(CONFIG_EFI)			+= efi.o vars.o reboot.o
+obj-$(CONFIG_EFI)			+= efi.o vars.o reboot.o memattr.o
+obj-$(CONFIG_EFI)			+= capsule.o
 obj-$(CONFIG_EFI_VARS)			+= efivars.o
 obj-$(CONFIG_EFI_ESRT)			+= esrt.o
 obj-$(CONFIG_EFI_VARS_PSTORE)		+= efi-pstore.o
@@ -18,7 +19,9 @@ obj-$(CONFIG_EFI_RUNTIME_MAP)		+= runtime-map.o
 obj-$(CONFIG_EFI_RUNTIME_WRAPPERS)	+= runtime-wrappers.o
 obj-$(CONFIG_EFI_STUB)			+= libstub/
 obj-$(CONFIG_EFI_FAKE_MEMMAP)		+= fake_mem.o
+obj-$(CONFIG_EFI_BOOTLOADER_CONTROL)	+= efibc.o
 
 arm-obj-$(CONFIG_EFI)			:= arm-init.o arm-runtime.o
 obj-$(CONFIG_ARM)			+= $(arm-obj-y)
 obj-$(CONFIG_ARM64)			+= $(arm-obj-y)
+obj-$(CONFIG_EFI_CAPSULE_LOADER)	+= capsule-loader.o
diff --git a/drivers/firmware/efi/arm-init.c b/drivers/firmware/efi/arm-init.c
index aa1f743152a2..ef90f0c4b70a 100644
--- a/drivers/firmware/efi/arm-init.c
+++ b/drivers/firmware/efi/arm-init.c
@@ -11,17 +11,19 @@
  *
  */
 
+#define pr_fmt(fmt)	"efi: " fmt
+
 #include <linux/efi.h>
 #include <linux/init.h>
 #include <linux/memblock.h>
 #include <linux/mm_types.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
+#include <linux/platform_device.h>
+#include <linux/screen_info.h>
 
 #include <asm/efi.h>
 
-struct efi_memory_map memmap;
-
 u64 efi_system_table;
 
 static int __init is_normal_ram(efi_memory_desc_t *md)
@@ -40,7 +42,7 @@ static phys_addr_t efi_to_phys(unsigned long addr)
 {
 	efi_memory_desc_t *md;
 
-	for_each_efi_memory_desc(&memmap, md) {
+	for_each_efi_memory_desc(md) {
 		if (!(md->attribute & EFI_MEMORY_RUNTIME))
 			continue;
 		if (md->virt_addr == 0)
@@ -53,6 +55,36 @@ static phys_addr_t efi_to_phys(unsigned long addr)
 	return addr;
 }
 
+static __initdata unsigned long screen_info_table = EFI_INVALID_TABLE_ADDR;
+
+static __initdata efi_config_table_type_t arch_tables[] = {
+	{LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID, NULL, &screen_info_table},
+	{NULL_GUID, NULL, NULL}
+};
+
+static void __init init_screen_info(void)
+{
+	struct screen_info *si;
+
+	if (screen_info_table != EFI_INVALID_TABLE_ADDR) {
+		si = early_memremap_ro(screen_info_table, sizeof(*si));
+		if (!si) {
+			pr_err("Could not map screen_info config table\n");
+			return;
+		}
+		screen_info = *si;
+		early_memunmap(si, sizeof(*si));
+
+		/* dummycon on ARM needs non-zero values for columns/lines */
+		screen_info.orig_video_cols = 80;
+		screen_info.orig_video_lines = 25;
+	}
+
+	if (screen_info.orig_video_isVGA == VIDEO_TYPE_EFI &&
+	    memblock_is_map_memory(screen_info.lfb_base))
+		memblock_mark_nomap(screen_info.lfb_base, screen_info.lfb_size);
+}
+
 static int __init uefi_init(void)
 {
 	efi_char16_t *c16;
@@ -85,6 +117,8 @@ static int __init uefi_init(void)
 			efi.systab->hdr.revision >> 16,
 			efi.systab->hdr.revision & 0xffff);
 
+	efi.runtime_version = efi.systab->hdr.revision;
+
 	/* Show what we know for posterity */
 	c16 = early_memremap_ro(efi_to_phys(efi.systab->fw_vendor),
 				sizeof(vendor) * sizeof(efi_char16_t));
@@ -108,7 +142,8 @@ static int __init uefi_init(void)
 		goto out;
 	}
 	retval = efi_config_parse_tables(config_tables, efi.systab->nr_tables,
-					 sizeof(efi_config_table_t), NULL);
+					 sizeof(efi_config_table_t),
+					 arch_tables);
 
 	early_memunmap(config_tables, table_size);
 out:
@@ -143,7 +178,7 @@ static __init void reserve_regions(void)
 	if (efi_enabled(EFI_DBG))
 		pr_info("Processing EFI memory map:\n");
 
-	for_each_efi_memory_desc(&memmap, md) {
+	for_each_efi_memory_desc(md) {
 		paddr = md->phys_addr;
 		npages = md->num_pages;
 
@@ -184,9 +219,9 @@ void __init efi_init(void)
 
 	efi_system_table = params.system_table;
 
-	memmap.phys_map = params.mmap;
-	memmap.map = early_memremap_ro(params.mmap, params.mmap_size);
-	if (memmap.map == NULL) {
+	efi.memmap.phys_map = params.mmap;
+	efi.memmap.map = early_memremap_ro(params.mmap, params.mmap_size);
+	if (efi.memmap.map == NULL) {
 		/*
 		* If we are booting via UEFI, the UEFI memory map is the only
 		* description of memory we have, so there is little point in
@@ -194,16 +229,37 @@ void __init efi_init(void)
 		*/
 		panic("Unable to map EFI memory map.\n");
 	}
-	memmap.map_end = memmap.map + params.mmap_size;
-	memmap.desc_size = params.desc_size;
-	memmap.desc_version = params.desc_ver;
+	efi.memmap.map_end = efi.memmap.map + params.mmap_size;
+	efi.memmap.desc_size = params.desc_size;
+	efi.memmap.desc_version = params.desc_ver;
+
+	WARN(efi.memmap.desc_version != 1,
+	     "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
+	      efi.memmap.desc_version);
 
 	if (uefi_init() < 0)
 		return;
 
 	reserve_regions();
-	early_memunmap(memmap.map, params.mmap_size);
-	memblock_mark_nomap(params.mmap & PAGE_MASK,
-			    PAGE_ALIGN(params.mmap_size +
-				       (params.mmap & ~PAGE_MASK)));
+	efi_memattr_init();
+	early_memunmap(efi.memmap.map, params.mmap_size);
+
+	memblock_reserve(params.mmap & PAGE_MASK,
+			 PAGE_ALIGN(params.mmap_size +
+				    (params.mmap & ~PAGE_MASK)));
+
+	init_screen_info();
+}
+
+static int __init register_gop_device(void)
+{
+	void *pd;
+
+	if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
+		return 0;
+
+	pd = platform_device_register_data(NULL, "efi-framebuffer", 0,
+					   &screen_info, sizeof(screen_info));
+	return PTR_ERR_OR_ZERO(pd);
 }
+subsys_initcall(register_gop_device);
diff --git a/drivers/firmware/efi/arm-runtime.c b/drivers/firmware/efi/arm-runtime.c
index 6ae21e41a429..17ccf0a8787a 100644
--- a/drivers/firmware/efi/arm-runtime.c
+++ b/drivers/firmware/efi/arm-runtime.c
@@ -42,11 +42,13 @@ static struct mm_struct efi_mm = {
 static bool __init efi_virtmap_init(void)
 {
 	efi_memory_desc_t *md;
+	bool systab_found;
 
 	efi_mm.pgd = pgd_alloc(&efi_mm);
 	init_new_context(NULL, &efi_mm);
 
-	for_each_efi_memory_desc(&memmap, md) {
+	systab_found = false;
+	for_each_efi_memory_desc(md) {
 		phys_addr_t phys = md->phys_addr;
 		int ret;
 
@@ -64,7 +66,25 @@ static bool __init efi_virtmap_init(void)
 				&phys, ret);
 			return false;
 		}
+		/*
+		 * If this entry covers the address of the UEFI system table,
+		 * calculate and record its virtual address.
+		 */
+		if (efi_system_table >= phys &&
+		    efi_system_table < phys + (md->num_pages * EFI_PAGE_SIZE)) {
+			efi.systab = (void *)(unsigned long)(efi_system_table -
+							     phys + md->virt_addr);
+			systab_found = true;
+		}
+	}
+	if (!systab_found) {
+		pr_err("No virtual mapping found for the UEFI System Table\n");
+		return false;
 	}
+
+	if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions))
+		return false;
+
 	return true;
 }
 
@@ -89,26 +109,17 @@ static int __init arm_enable_runtime_services(void)
 
 	pr_info("Remapping and enabling EFI services.\n");
 
-	mapsize = memmap.map_end - memmap.map;
-	memmap.map = (__force void *)ioremap_cache(memmap.phys_map,
-						   mapsize);
-	if (!memmap.map) {
-		pr_err("Failed to remap EFI memory map\n");
-		return -ENOMEM;
-	}
-	memmap.map_end = memmap.map + mapsize;
-	efi.memmap = &memmap;
+	mapsize = efi.memmap.map_end - efi.memmap.map;
 
-	efi.systab = (__force void *)ioremap_cache(efi_system_table,
-						   sizeof(efi_system_table_t));
-	if (!efi.systab) {
-		pr_err("Failed to remap EFI System Table\n");
+	efi.memmap.map = memremap(efi.memmap.phys_map, mapsize, MEMREMAP_WB);
+	if (!efi.memmap.map) {
+		pr_err("Failed to remap EFI memory map\n");
 		return -ENOMEM;
 	}
-	set_bit(EFI_SYSTEM_TABLES, &efi.flags);
+	efi.memmap.map_end = efi.memmap.map + mapsize;
 
 	if (!efi_virtmap_init()) {
-		pr_err("No UEFI virtual mapping was installed -- runtime services will not be available\n");
+		pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n");
 		return -ENOMEM;
 	}
 
@@ -116,8 +127,6 @@ static int __init arm_enable_runtime_services(void)
 	efi_native_runtime_setup();
 	set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
 
-	efi.runtime_version = efi.systab->hdr.revision;
-
 	return 0;
 }
 early_initcall(arm_enable_runtime_services);
diff --git a/drivers/firmware/efi/capsule-loader.c b/drivers/firmware/efi/capsule-loader.c
new file mode 100644
index 000000000000..c99c24bc79b0
--- /dev/null
+++ b/drivers/firmware/efi/capsule-loader.c
@@ -0,0 +1,343 @@
+/*
+ * EFI capsule loader driver.
+ *
+ * Copyright 2015 Intel Corporation
+ *
+ * This file is part of the Linux kernel, and is made available under
+ * the terms of the GNU General Public License version 2.
+ */
+
+#define pr_fmt(fmt) "efi: " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/miscdevice.h>
+#include <linux/highmem.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/efi.h>
+
+#define NO_FURTHER_WRITE_ACTION -1
+
+struct capsule_info {
+	bool		header_obtained;
+	int		reset_type;
+	long		index;
+	size_t		count;
+	size_t		total_size;
+	struct page	**pages;
+	size_t		page_bytes_remain;
+};
+
+/**
+ * efi_free_all_buff_pages - free all previous allocated buffer pages
+ * @cap_info: pointer to current instance of capsule_info structure
+ *
+ *	In addition to freeing buffer pages, it flags NO_FURTHER_WRITE_ACTION
+ *	to cease processing data in subsequent write(2) calls until close(2)
+ *	is called.
+ **/
+static void efi_free_all_buff_pages(struct capsule_info *cap_info)
+{
+	while (cap_info->index > 0)
+		__free_page(cap_info->pages[--cap_info->index]);
+
+	cap_info->index = NO_FURTHER_WRITE_ACTION;
+}
+
+/**
+ * efi_capsule_setup_info - obtain the efi capsule header in the binary and
+ *			    setup capsule_info structure
+ * @cap_info: pointer to current instance of capsule_info structure
+ * @kbuff: a mapped first page buffer pointer
+ * @hdr_bytes: the total received number of bytes for efi header
+ **/
+static ssize_t efi_capsule_setup_info(struct capsule_info *cap_info,
+				      void *kbuff, size_t hdr_bytes)
+{
+	efi_capsule_header_t *cap_hdr;
+	size_t pages_needed;
+	int ret;
+	void *temp_page;
+
+	/* Only process data block that is larger than efi header size */
+	if (hdr_bytes < sizeof(efi_capsule_header_t))
+		return 0;
+
+	/* Reset back to the correct offset of header */
+	cap_hdr = kbuff - cap_info->count;
+	pages_needed = ALIGN(cap_hdr->imagesize, PAGE_SIZE) >> PAGE_SHIFT;
+
+	if (pages_needed == 0) {
+		pr_err("%s: pages count invalid\n", __func__);
+		return -EINVAL;
+	}
+
+	/* Check if the capsule binary supported */
+	ret = efi_capsule_supported(cap_hdr->guid, cap_hdr->flags,
+				    cap_hdr->imagesize,
+				    &cap_info->reset_type);
+	if (ret) {
+		pr_err("%s: efi_capsule_supported() failed\n",
+		       __func__);
+		return ret;
+	}
+
+	cap_info->total_size = cap_hdr->imagesize;
+	temp_page = krealloc(cap_info->pages,
+			     pages_needed * sizeof(void *),
+			     GFP_KERNEL | __GFP_ZERO);
+	if (!temp_page) {
+		pr_debug("%s: krealloc() failed\n", __func__);
+		return -ENOMEM;
+	}
+
+	cap_info->pages = temp_page;
+	cap_info->header_obtained = true;
+
+	return 0;
+}
+
+/**
+ * efi_capsule_submit_update - invoke the efi_capsule_update API once binary
+ *			       upload done
+ * @cap_info: pointer to current instance of capsule_info structure
+ **/
+static ssize_t efi_capsule_submit_update(struct capsule_info *cap_info)
+{
+	int ret;
+	void *cap_hdr_temp;
+
+	cap_hdr_temp = kmap(cap_info->pages[0]);
+	if (!cap_hdr_temp) {
+		pr_debug("%s: kmap() failed\n", __func__);
+		return -EFAULT;
+	}
+
+	ret = efi_capsule_update(cap_hdr_temp, cap_info->pages);
+	kunmap(cap_info->pages[0]);
+	if (ret) {
+		pr_err("%s: efi_capsule_update() failed\n", __func__);
+		return ret;
+	}
+
+	/* Indicate capsule binary uploading is done */
+	cap_info->index = NO_FURTHER_WRITE_ACTION;
+	pr_info("%s: Successfully upload capsule file with reboot type '%s'\n",
+		__func__, !cap_info->reset_type ? "RESET_COLD" :
+		cap_info->reset_type == 1 ? "RESET_WARM" :
+		"RESET_SHUTDOWN");
+	return 0;
+}
+
+/**
+ * efi_capsule_write - store the capsule binary and pass it to
+ *		       efi_capsule_update() API
+ * @file: file pointer
+ * @buff: buffer pointer
+ * @count: number of bytes in @buff
+ * @offp: not used
+ *
+ *	Expectation:
+ *	- A user space tool should start at the beginning of capsule binary and
+ *	  pass data in sequentially.
+ *	- Users should close and re-open this file note in order to upload more
+ *	  capsules.
+ *	- After an error returned, user should close the file and restart the
+ *	  operation for the next try otherwise -EIO will be returned until the
+ *	  file is closed.
+ *	- An EFI capsule header must be located at the beginning of capsule
+ *	  binary file and passed in as first block data of write operation.
+ **/
+static ssize_t efi_capsule_write(struct file *file, const char __user *buff,
+				 size_t count, loff_t *offp)
+{
+	int ret = 0;
+	struct capsule_info *cap_info = file->private_data;
+	struct page *page;
+	void *kbuff = NULL;
+	size_t write_byte;
+
+	if (count == 0)
+		return 0;
+
+	/* Return error while NO_FURTHER_WRITE_ACTION is flagged */
+	if (cap_info->index < 0)
+		return -EIO;
+
+	/* Only alloc a new page when previous page is full */
+	if (!cap_info->page_bytes_remain) {
+		page = alloc_page(GFP_KERNEL);
+		if (!page) {
+			pr_debug("%s: alloc_page() failed\n", __func__);
+			ret = -ENOMEM;
+			goto failed;
+		}
+
+		cap_info->pages[cap_info->index++] = page;
+		cap_info->page_bytes_remain = PAGE_SIZE;
+	}
+
+	page = cap_info->pages[cap_info->index - 1];
+
+	kbuff = kmap(page);
+	if (!kbuff) {
+		pr_debug("%s: kmap() failed\n", __func__);
+		ret = -EFAULT;
+		goto failed;
+	}
+	kbuff += PAGE_SIZE - cap_info->page_bytes_remain;
+
+	/* Copy capsule binary data from user space to kernel space buffer */
+	write_byte = min_t(size_t, count, cap_info->page_bytes_remain);
+	if (copy_from_user(kbuff, buff, write_byte)) {
+		pr_debug("%s: copy_from_user() failed\n", __func__);
+		ret = -EFAULT;
+		goto fail_unmap;
+	}
+	cap_info->page_bytes_remain -= write_byte;
+
+	/* Setup capsule binary info structure */
+	if (!cap_info->header_obtained) {
+		ret = efi_capsule_setup_info(cap_info, kbuff,
+					     cap_info->count + write_byte);
+		if (ret)
+			goto fail_unmap;
+	}
+
+	cap_info->count += write_byte;
+	kunmap(page);
+
+	/* Submit the full binary to efi_capsule_update() API */
+	if (cap_info->header_obtained &&
+	    cap_info->count >= cap_info->total_size) {
+		if (cap_info->count > cap_info->total_size) {
+			pr_err("%s: upload size exceeded header defined size\n",
+			       __func__);
+			ret = -EINVAL;
+			goto failed;
+		}
+
+		ret = efi_capsule_submit_update(cap_info);
+		if (ret)
+			goto failed;
+	}
+
+	return write_byte;
+
+fail_unmap:
+	kunmap(page);
+failed:
+	efi_free_all_buff_pages(cap_info);
+	return ret;
+}
+
+/**
+ * efi_capsule_flush - called by file close or file flush
+ * @file: file pointer
+ * @id: not used
+ *
+ *	If a capsule is being partially uploaded then calling this function
+ *	will be treated as upload termination and will free those completed
+ *	buffer pages and -ECANCELED will be returned.
+ **/
+static int efi_capsule_flush(struct file *file, fl_owner_t id)
+{
+	int ret = 0;
+	struct capsule_info *cap_info = file->private_data;
+
+	if (cap_info->index > 0) {
+		pr_err("%s: capsule upload not complete\n", __func__);
+		efi_free_all_buff_pages(cap_info);
+		ret = -ECANCELED;
+	}
+
+	return ret;
+}
+
+/**
+ * efi_capsule_release - called by file close
+ * @inode: not used
+ * @file: file pointer
+ *
+ *	We will not free successfully submitted pages since efi update
+ *	requires data to be maintained across system reboot.
+ **/
+static int efi_capsule_release(struct inode *inode, struct file *file)
+{
+	struct capsule_info *cap_info = file->private_data;
+
+	kfree(cap_info->pages);
+	kfree(file->private_data);
+	file->private_data = NULL;
+	return 0;
+}
+
+/**
+ * efi_capsule_open - called by file open
+ * @inode: not used
+ * @file: file pointer
+ *
+ *	Will allocate each capsule_info memory for each file open call.
+ *	This provided the capability to support multiple file open feature
+ *	where user is not needed to wait for others to finish in order to
+ *	upload their capsule binary.
+ **/
+static int efi_capsule_open(struct inode *inode, struct file *file)
+{
+	struct capsule_info *cap_info;
+
+	cap_info = kzalloc(sizeof(*cap_info), GFP_KERNEL);
+	if (!cap_info)
+		return -ENOMEM;
+
+	cap_info->pages = kzalloc(sizeof(void *), GFP_KERNEL);
+	if (!cap_info->pages) {
+		kfree(cap_info);
+		return -ENOMEM;
+	}
+
+	file->private_data = cap_info;
+
+	return 0;
+}
+
+static const struct file_operations efi_capsule_fops = {
+	.owner = THIS_MODULE,
+	.open = efi_capsule_open,
+	.write = efi_capsule_write,
+	.flush = efi_capsule_flush,
+	.release = efi_capsule_release,
+	.llseek = no_llseek,
+};
+
+static struct miscdevice efi_capsule_misc = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "efi_capsule_loader",
+	.fops = &efi_capsule_fops,
+};
+
+static int __init efi_capsule_loader_init(void)
+{
+	int ret;
+
+	if (!efi_enabled(EFI_RUNTIME_SERVICES))
+		return -ENODEV;
+
+	ret = misc_register(&efi_capsule_misc);
+	if (ret)
+		pr_err("%s: Failed to register misc char file note\n",
+		       __func__);
+
+	return ret;
+}
+module_init(efi_capsule_loader_init);
+
+static void __exit efi_capsule_loader_exit(void)
+{
+	misc_deregister(&efi_capsule_misc);
+}
+module_exit(efi_capsule_loader_exit);
+
+MODULE_DESCRIPTION("EFI capsule firmware binary loader");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/firmware/efi/capsule.c b/drivers/firmware/efi/capsule.c
new file mode 100644
index 000000000000..53b9fd2293ee
--- /dev/null
+++ b/drivers/firmware/efi/capsule.c
@@ -0,0 +1,308 @@
+/*
+ * EFI capsule support.
+ *
+ * Copyright 2013 Intel Corporation; author Matt Fleming
+ *
+ * This file is part of the Linux kernel, and is made available under
+ * the terms of the GNU General Public License version 2.
+ */
+
+#define pr_fmt(fmt) "efi: " fmt
+
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/highmem.h>
+#include <linux/efi.h>
+#include <linux/vmalloc.h>
+#include <asm/io.h>
+
+typedef struct {
+	u64 length;
+	u64 data;
+} efi_capsule_block_desc_t;
+
+static bool capsule_pending;
+static bool stop_capsules;
+static int efi_reset_type = -1;
+
+/*
+ * capsule_mutex serialises access to both capsule_pending and
+ * efi_reset_type and stop_capsules.
+ */
+static DEFINE_MUTEX(capsule_mutex);
+
+/**
+ * efi_capsule_pending - has a capsule been passed to the firmware?
+ * @reset_type: store the type of EFI reset if capsule is pending
+ *
+ * To ensure that the registered capsule is processed correctly by the
+ * firmware we need to perform a specific type of reset. If a capsule is
+ * pending return the reset type in @reset_type.
+ *
+ * This function will race with callers of efi_capsule_update(), for
+ * example, calling this function while somebody else is in
+ * efi_capsule_update() but hasn't reached efi_capsue_update_locked()
+ * will miss the updates to capsule_pending and efi_reset_type after
+ * efi_capsule_update_locked() completes.
+ *
+ * A non-racy use is from platform reboot code because we use
+ * system_state to ensure no capsules can be sent to the firmware once
+ * we're at SYSTEM_RESTART. See efi_capsule_update_locked().
+ */
+bool efi_capsule_pending(int *reset_type)
+{
+	if (!capsule_pending)
+		return false;
+
+	if (reset_type)
+		*reset_type = efi_reset_type;
+
+	return true;
+}
+
+/*
+ * Whitelist of EFI capsule flags that we support.
+ *
+ * We do not handle EFI_CAPSULE_INITIATE_RESET because that would
+ * require us to prepare the kernel for reboot. Refuse to load any
+ * capsules with that flag and any other flags that we do not know how
+ * to handle.
+ */
+#define EFI_CAPSULE_SUPPORTED_FLAG_MASK			\
+	(EFI_CAPSULE_PERSIST_ACROSS_RESET | EFI_CAPSULE_POPULATE_SYSTEM_TABLE)
+
+/**
+ * efi_capsule_supported - does the firmware support the capsule?
+ * @guid: vendor guid of capsule
+ * @flags: capsule flags
+ * @size: size of capsule data
+ * @reset: the reset type required for this capsule
+ *
+ * Check whether a capsule with @flags is supported by the firmware
+ * and that @size doesn't exceed the maximum size for a capsule.
+ *
+ * No attempt is made to check @reset against the reset type required
+ * by any pending capsules because of the races involved.
+ */
+int efi_capsule_supported(efi_guid_t guid, u32 flags, size_t size, int *reset)
+{
+	efi_capsule_header_t capsule;
+	efi_capsule_header_t *cap_list[] = { &capsule };
+	efi_status_t status;
+	u64 max_size;
+
+	if (flags & ~EFI_CAPSULE_SUPPORTED_FLAG_MASK)
+		return -EINVAL;
+
+	capsule.headersize = capsule.imagesize = sizeof(capsule);
+	memcpy(&capsule.guid, &guid, sizeof(efi_guid_t));
+	capsule.flags = flags;
+
+	status = efi.query_capsule_caps(cap_list, 1, &max_size, reset);
+	if (status != EFI_SUCCESS)
+		return efi_status_to_err(status);
+
+	if (size > max_size)
+		return -ENOSPC;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(efi_capsule_supported);
+
+/*
+ * Every scatter gather list (block descriptor) page must end with a
+ * continuation pointer. The last continuation pointer of the last
+ * page must be zero to mark the end of the chain.
+ */
+#define SGLIST_PER_PAGE	((PAGE_SIZE / sizeof(efi_capsule_block_desc_t)) - 1)
+
+/*
+ * How many scatter gather list (block descriptor) pages do we need
+ * to map @count pages?
+ */
+static inline unsigned int sg_pages_num(unsigned int count)
+{
+	return DIV_ROUND_UP(count, SGLIST_PER_PAGE);
+}
+
+/**
+ * efi_capsule_update_locked - pass a single capsule to the firmware
+ * @capsule: capsule to send to the firmware
+ * @sg_pages: array of scatter gather (block descriptor) pages
+ * @reset: the reset type required for @capsule
+ *
+ * Since this function must be called under capsule_mutex check
+ * whether efi_reset_type will conflict with @reset, and atomically
+ * set it and capsule_pending if a capsule was successfully sent to
+ * the firmware.
+ *
+ * We also check to see if the system is about to restart, and if so,
+ * abort. This avoids races between efi_capsule_update() and
+ * efi_capsule_pending().
+ */
+static int
+efi_capsule_update_locked(efi_capsule_header_t *capsule,
+			  struct page **sg_pages, int reset)
+{
+	efi_physical_addr_t sglist_phys;
+	efi_status_t status;
+
+	lockdep_assert_held(&capsule_mutex);
+
+	/*
+	 * If someone has already registered a capsule that requires a
+	 * different reset type, we're out of luck and must abort.
+	 */
+	if (efi_reset_type >= 0 && efi_reset_type != reset) {
+		pr_err("Conflicting capsule reset type %d (%d).\n",
+		       reset, efi_reset_type);
+		return -EINVAL;
+	}
+
+	/*
+	 * If the system is getting ready to restart it may have
+	 * called efi_capsule_pending() to make decisions (such as
+	 * whether to force an EFI reboot), and we're racing against
+	 * that call. Abort in that case.
+	 */
+	if (unlikely(stop_capsules)) {
+		pr_warn("Capsule update raced with reboot, aborting.\n");
+		return -EINVAL;
+	}
+
+	sglist_phys = page_to_phys(sg_pages[0]);
+
+	status = efi.update_capsule(&capsule, 1, sglist_phys);
+	if (status == EFI_SUCCESS) {
+		capsule_pending = true;
+		efi_reset_type = reset;
+	}
+
+	return efi_status_to_err(status);
+}
+
+/**
+ * efi_capsule_update - send a capsule to the firmware
+ * @capsule: capsule to send to firmware
+ * @pages: an array of capsule data pages
+ *
+ * Build a scatter gather list with EFI capsule block descriptors to
+ * map the capsule described by @capsule with its data in @pages and
+ * send it to the firmware via the UpdateCapsule() runtime service.
+ *
+ * @capsule must be a virtual mapping of the first page in @pages
+ * (@pages[0]) in the kernel address space. That is, a
+ * capsule_header_t that describes the entire contents of the capsule
+ * must be at the start of the first data page.
+ *
+ * Even though this function will validate that the firmware supports
+ * the capsule guid, users will likely want to check that
+ * efi_capsule_supported() returns true before calling this function
+ * because it makes it easier to print helpful error messages.
+ *
+ * If the capsule is successfully submitted to the firmware, any
+ * subsequent calls to efi_capsule_pending() will return true. @pages
+ * must not be released or modified if this function returns
+ * successfully.
+ *
+ * Callers must be prepared for this function to fail, which can
+ * happen if we raced with system reboot or if there is already a
+ * pending capsule that has a reset type that conflicts with the one
+ * required by @capsule. Do NOT use efi_capsule_pending() to detect
+ * this conflict since that would be racy. Instead, submit the capsule
+ * to efi_capsule_update() and check the return value.
+ *
+ * Return 0 on success, a converted EFI status code on failure.
+ */
+int efi_capsule_update(efi_capsule_header_t *capsule, struct page **pages)
+{
+	u32 imagesize = capsule->imagesize;
+	efi_guid_t guid = capsule->guid;
+	unsigned int count, sg_count;
+	u32 flags = capsule->flags;
+	struct page **sg_pages;
+	int rv, reset_type;
+	int i, j;
+
+	rv = efi_capsule_supported(guid, flags, imagesize, &reset_type);
+	if (rv)
+		return rv;
+
+	count = DIV_ROUND_UP(imagesize, PAGE_SIZE);
+	sg_count = sg_pages_num(count);
+
+	sg_pages = kzalloc(sg_count * sizeof(*sg_pages), GFP_KERNEL);
+	if (!sg_pages)
+		return -ENOMEM;
+
+	for (i = 0; i < sg_count; i++) {
+		sg_pages[i] = alloc_page(GFP_KERNEL);
+		if (!sg_pages[i]) {
+			rv = -ENOMEM;
+			goto out;
+		}
+	}
+
+	for (i = 0; i < sg_count; i++) {
+		efi_capsule_block_desc_t *sglist;
+
+		sglist = kmap(sg_pages[i]);
+		if (!sglist) {
+			rv = -ENOMEM;
+			goto out;
+		}
+
+		for (j = 0; j < SGLIST_PER_PAGE && count > 0; j++) {
+			u64 sz = min_t(u64, imagesize, PAGE_SIZE);
+
+			sglist[j].length = sz;
+			sglist[j].data = page_to_phys(*pages++);
+
+			imagesize -= sz;
+			count--;
+		}
+
+		/* Continuation pointer */
+		sglist[j].length = 0;
+
+		if (i + 1 == sg_count)
+			sglist[j].data = 0;
+		else
+			sglist[j].data = page_to_phys(sg_pages[i + 1]);
+
+		kunmap(sg_pages[i]);
+	}
+
+	mutex_lock(&capsule_mutex);
+	rv = efi_capsule_update_locked(capsule, sg_pages, reset_type);
+	mutex_unlock(&capsule_mutex);
+
+out:
+	for (i = 0; rv && i < sg_count; i++) {
+		if (sg_pages[i])
+			__free_page(sg_pages[i]);
+	}
+
+	kfree(sg_pages);
+	return rv;
+}
+EXPORT_SYMBOL_GPL(efi_capsule_update);
+
+static int capsule_reboot_notify(struct notifier_block *nb, unsigned long event, void *cmd)
+{
+	mutex_lock(&capsule_mutex);
+	stop_capsules = true;
+	mutex_unlock(&capsule_mutex);
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block capsule_reboot_nb = {