arch/arm64/kernel/efi.c - third_party/linux - Git at Google

 /*
  * Extensible Firmware Interface
  *
  * Based on Extensible Firmware Interface Specification version 2.4
  *
  * Copyright (C) 2013, 2014 Linaro Ltd.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  */

 #include <linux/atomic.h>
 #include <linux/dmi.h>
 #include <linux/efi.h>
 #include <linux/export.h>
 #include <linux/memblock.h>
 #include <linux/mm_types.h>
 #include <linux/bootmem.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
 #include <linux/preempt.h>
 #include <linux/rbtree.h>
 #include <linux/rwsem.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>

 #include <asm/cacheflush.h>
 #include <asm/efi.h>
 #include <asm/tlbflush.h>
 #include <asm/mmu_context.h>
 #include <asm/mmu.h>
 #include <asm/pgtable.h>

 struct efi_memory_map memmap;

 static u64 efi_system_table;

 static pgd_t efi_pgd[PTRS_PER_PGD] __page_aligned_bss;

 static struct mm_struct efi_mm = {
 	.mm_rb			= RB_ROOT,
 	.pgd			= efi_pgd,
 	.mm_users		= ATOMIC_INIT(2),
 	.mm_count		= ATOMIC_INIT(1),
 	.mmap_sem		= __RWSEM_INITIALIZER(efi_mm.mmap_sem),
 	.page_table_lock	= __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
 	.mmlist			= LIST_HEAD_INIT(efi_mm.mmlist),
 };

 static int __init is_normal_ram(efi_memory_desc_t *md)
 {
 	if (md->attribute & EFI_MEMORY_WB)
 		return 1;
 	return 0;
 }

 /*
  * Translate a EFI virtual address into a physical address: this is necessary,
  * as some data members of the EFI system table are virtually remapped after
  * SetVirtualAddressMap() has been called.
  */
 static phys_addr_t efi_to_phys(unsigned long addr)
 {
 	efi_memory_desc_t *md;

 	for_each_efi_memory_desc(&memmap, md) {
 		if (!(md->attribute & EFI_MEMORY_RUNTIME))
 			continue;
 		if (md->virt_addr == 0)
 			/* no virtual mapping has been installed by the stub */
 			break;
 		if (md->virt_addr <= addr &&
 		    (addr - md->virt_addr) < (md->num_pages << EFI_PAGE_SHIFT))
 			return md->phys_addr + addr - md->virt_addr;
 	}
 	return addr;
 }

 static int __init uefi_init(void)
 {
 	efi_char16_t *c16;
 	void *config_tables;
 	u64 table_size;
 	char vendor[100] = "unknown";
 	int i, retval;

 	efi.systab = early_memremap(efi_system_table,
 				    sizeof(efi_system_table_t));
 	if (efi.systab == NULL) {
 		pr_warn("Unable to map EFI system table.\n");
 		return -ENOMEM;
 	}

 	set_bit(EFI_BOOT, &efi.flags);
 	set_bit(EFI_64BIT, &efi.flags);

 	/*
 	 * Verify the EFI Table
 	 */
 	if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) {
 		pr_err("System table signature incorrect\n");
 		retval = -EINVAL;
 		goto out;
 	}
 	if ((efi.systab->hdr.revision >> 16) < 2)
 		pr_warn("Warning: EFI system table version %d.%02d, expected 2.00 or greater\n",
 			efi.systab->hdr.revision >> 16,
 			efi.systab->hdr.revision & 0xffff);

 	/* Show what we know for posterity */
 	c16 = early_memremap(efi_to_phys(efi.systab->fw_vendor),
 			     sizeof(vendor) * sizeof(efi_char16_t));
 	if (c16) {
 		for (i = 0; i < (int) sizeof(vendor) - 1 && *c16; ++i)
 			vendor[i] = c16[i];
 		vendor[i] = '\0';
 		early_memunmap(c16, sizeof(vendor) * sizeof(efi_char16_t));
 	}

 	pr_info("EFI v%u.%.02u by %s\n",
 		efi.systab->hdr.revision >> 16,
 		efi.systab->hdr.revision & 0xffff, vendor);

 	table_size = sizeof(efi_config_table_64_t) * efi.systab->nr_tables;
 	config_tables = early_memremap(efi_to_phys(efi.systab->tables),
 				       table_size);
 	if (config_tables == NULL) {
 		pr_warn("Unable to map EFI config table array.\n");
 		retval = -ENOMEM;
 		goto out;
 	}
 	retval = efi_config_parse_tables(config_tables, efi.systab->nr_tables,
 					 sizeof(efi_config_table_64_t), NULL);

 	early_memunmap(config_tables, table_size);
 out:
 	early_memunmap(efi.systab,  sizeof(efi_system_table_t));
 	return retval;
 }

 /*
  * Return true for RAM regions we want to permanently reserve.
  */
 static __init int is_reserve_region(efi_memory_desc_t *md)
 {
 	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:
 	case EFI_PERSISTENT_MEMORY:
 		return 0;
 	default:
 		break;
 	}
 	return is_normal_ram(md);
 }

 static __init void reserve_regions(void)
 {
 	efi_memory_desc_t *md;
 	u64 paddr, npages, size;

 	if (efi_enabled(EFI_DBG))
 		pr_info("Processing EFI memory map:\n");

 	for_each_efi_memory_desc(&memmap, md) {
 		paddr = md->phys_addr;
 		npages = md->num_pages;

 		if (efi_enabled(EFI_DBG)) {
 			char buf[64];

 			pr_info("  0x%012llx-0x%012llx %s",
 				paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
 				efi_md_typeattr_format(buf, sizeof(buf), md));
 		}

 		memrange_efi_to_native(&paddr, &npages);
 		size = npages << PAGE_SHIFT;

 		if (is_normal_ram(md))
 			early_init_dt_add_memory_arch(paddr, size);

 		if (is_reserve_region(md)) {
 			memblock_reserve(paddr, size);
 			if (efi_enabled(EFI_DBG))
 				pr_cont("*");
 		}

 		if (efi_enabled(EFI_DBG))
 			pr_cont("\n");
 	}

 	set_bit(EFI_MEMMAP, &efi.flags);
 }

 void __init efi_init(void)
 {
 	struct efi_fdt_params params;

 	/* Grab UEFI information placed in FDT by stub */
 	if (!efi_get_fdt_params(&params))
 		return;

 	efi_system_table = params.system_table;

 	memblock_reserve(params.mmap & PAGE_MASK,
 			 PAGE_ALIGN(params.mmap_size + (params.mmap & ~PAGE_MASK)));
 	memmap.phys_map = params.mmap;
 	memmap.map = early_memremap(params.mmap, params.mmap_size);
 	if (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
 		* proceeding if we cannot access it.
 		*/
 		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;

 	if (uefi_init() < 0)
 		return;

 	reserve_regions();
 	early_memunmap(memmap.map, params.mmap_size);
 }

 static bool __init efi_virtmap_init(void)
 {
 	efi_memory_desc_t *md;

 	init_new_context(NULL, &efi_mm);

 	for_each_efi_memory_desc(&memmap, md) {
 		pgprot_t prot;

 		if (!(md->attribute & EFI_MEMORY_RUNTIME))
 			continue;
 		if (md->virt_addr == 0)
 			return false;

 		pr_info("  EFI remap 0x%016llx => %p\n",
 			md->phys_addr, (void *)md->virt_addr);

 		/*
 		 * Only regions of type EFI_RUNTIME_SERVICES_CODE need to be
 		 * executable, everything else can be mapped with the XN bits
 		 * set.
 		 */
 		if (!is_normal_ram(md))
 			prot = __pgprot(PROT_DEVICE_nGnRE);
 		else if (md->type == EFI_RUNTIME_SERVICES_CODE ||
 			 !PAGE_ALIGNED(md->phys_addr))
 			prot = PAGE_KERNEL_EXEC;
 		else
 			prot = PAGE_KERNEL;

 		create_pgd_mapping(&efi_mm, md->phys_addr, md->virt_addr,
 				   md->num_pages << EFI_PAGE_SHIFT,
 				   __pgprot(pgprot_val(prot) | PTE_NG));
 	}
 	return true;
 }

 /*
  * Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
  * non-early mapping of the UEFI system table and virtual mappings for all
  * EFI_MEMORY_RUNTIME regions.
  */
 static int __init arm64_enable_runtime_services(void)
 {
 	u64 mapsize;

 	if (!efi_enabled(EFI_BOOT)) {
 		pr_info("EFI services will not be available.\n");
 		return 0;
 	}

 	if (efi_runtime_disabled()) {
 		pr_info("EFI runtime services will be disabled.\n");
 		return 0;
 	}

 	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;

 	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");
 		return -ENOMEM;
 	}
 	set_bit(EFI_SYSTEM_TABLES, &efi.flags);

 	if (!efi_virtmap_init()) {
 		pr_err("No UEFI virtual mapping was installed -- runtime services will not be available\n");
 		return -ENOMEM;
 	}

 	/* Set up runtime services function pointers */
 	efi_native_runtime_setup();
 	set_bit(EFI_RUNTIME_SERVICES, &efi.flags);

 	efi.runtime_version = efi.systab->hdr.revision;

 	return 0;
 }
 early_initcall(arm64_enable_runtime_services);

 static int __init arm64_dmi_init(void)
 {
 	/*
 	 * On arm64, DMI depends on UEFI, and dmi_scan_machine() needs to
 	 * be called early because dmi_id_init(), which is an arch_initcall
 	 * itself, depends on dmi_scan_machine() having been called already.
 	 */
 	dmi_scan_machine();
 	if (dmi_available)
 		dmi_set_dump_stack_arch_desc();
 	return 0;
 }
 core_initcall(arm64_dmi_init);

 static void efi_set_pgd(struct mm_struct *mm)
 {
 	switch_mm(NULL, mm, NULL);
 }

 void efi_virtmap_load(void)
 {
 	preempt_disable();
 	efi_set_pgd(&efi_mm);
 }

 void efi_virtmap_unload(void)
 {
 	efi_set_pgd(current->active_mm);
 	preempt_enable();
 }

 /*
  * UpdateCapsule() depends on the system being shutdown via
  * ResetSystem().
  */
 bool efi_poweroff_required(void)
 {
 	return efi_enabled(EFI_RUNTIME_SERVICES);
 }
	/*
	* Extensible Firmware Interface
	*
	* Based on Extensible Firmware Interface Specification version 2.4
	*
	* Copyright (C) 2013, 2014 Linaro Ltd.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	*/

	#include <linux/atomic.h>
	#include <linux/dmi.h>
	#include <linux/efi.h>
	#include <linux/export.h>
	#include <linux/memblock.h>
	#include <linux/mm_types.h>
	#include <linux/bootmem.h>
	#include <linux/of.h>
	#include <linux/of_fdt.h>
	#include <linux/preempt.h>
	#include <linux/rbtree.h>
	#include <linux/rwsem.h>
	#include <linux/sched.h>
	#include <linux/slab.h>
	#include <linux/spinlock.h>

	#include <asm/cacheflush.h>
	#include <asm/efi.h>
	#include <asm/tlbflush.h>
	#include <asm/mmu_context.h>
	#include <asm/mmu.h>
	#include <asm/pgtable.h>

	struct efi_memory_map memmap;

	static u64 efi_system_table;

	static pgd_t efi_pgd[PTRS_PER_PGD] __page_aligned_bss;

	static struct mm_struct efi_mm = {
	.mm_rb = RB_ROOT,
	.pgd = efi_pgd,
	.mm_users = ATOMIC_INIT(2),
	.mm_count = ATOMIC_INIT(1),
	.mmap_sem = __RWSEM_INITIALIZER(efi_mm.mmap_sem),
	.page_table_lock = __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
	.mmlist = LIST_HEAD_INIT(efi_mm.mmlist),
	};

	static int __init is_normal_ram(efi_memory_desc_t *md)
	{
	if (md->attribute & EFI_MEMORY_WB)
	return 1;
	return 0;
	}

	/*
	* Translate a EFI virtual address into a physical address: this is necessary,
	* as some data members of the EFI system table are virtually remapped after
	* SetVirtualAddressMap() has been called.
	*/
	static phys_addr_t efi_to_phys(unsigned long addr)
	{
	efi_memory_desc_t *md;

	for_each_efi_memory_desc(&memmap, md) {
	if (!(md->attribute & EFI_MEMORY_RUNTIME))
	continue;
	if (md->virt_addr == 0)
	/* no virtual mapping has been installed by the stub */
	break;
	if (md->virt_addr <= addr &&
	(addr - md->virt_addr) < (md->num_pages << EFI_PAGE_SHIFT))
	return md->phys_addr + addr - md->virt_addr;
	}
	return addr;
	}

	static int __init uefi_init(void)
	{
	efi_char16_t *c16;
	void *config_tables;
	u64 table_size;
	char vendor[100] = "unknown";
	int i, retval;

	efi.systab = early_memremap(efi_system_table,
	sizeof(efi_system_table_t));
	if (efi.systab == NULL) {
	pr_warn("Unable to map EFI system table.\n");
	return -ENOMEM;
	}

	set_bit(EFI_BOOT, &efi.flags);
	set_bit(EFI_64BIT, &efi.flags);

	/*
	* Verify the EFI Table
	*/
	if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) {
	pr_err("System table signature incorrect\n");
	retval = -EINVAL;
	goto out;
	}
	if ((efi.systab->hdr.revision >> 16) < 2)
	pr_warn("Warning: EFI system table version %d.%02d, expected 2.00 or greater\n",
	efi.systab->hdr.revision >> 16,
	efi.systab->hdr.revision & 0xffff);

	/* Show what we know for posterity */
	c16 = early_memremap(efi_to_phys(efi.systab->fw_vendor),
	sizeof(vendor) * sizeof(efi_char16_t));
	if (c16) {
	for (i = 0; i < (int) sizeof(vendor) - 1 && *c16; ++i)
	vendor[i] = c16[i];
	vendor[i] = '\0';
	early_memunmap(c16, sizeof(vendor) * sizeof(efi_char16_t));
	}

	pr_info("EFI v%u.%.02u by %s\n",
	efi.systab->hdr.revision >> 16,
	efi.systab->hdr.revision & 0xffff, vendor);

	table_size = sizeof(efi_config_table_64_t) * efi.systab->nr_tables;
	config_tables = early_memremap(efi_to_phys(efi.systab->tables),
	table_size);
	if (config_tables == NULL) {
	pr_warn("Unable to map EFI config table array.\n");
	retval = -ENOMEM;
	goto out;
	}
	retval = efi_config_parse_tables(config_tables, efi.systab->nr_tables,
	sizeof(efi_config_table_64_t), NULL);

	early_memunmap(config_tables, table_size);
	out:
	early_memunmap(efi.systab, sizeof(efi_system_table_t));
	return retval;
	}

	/*
	* Return true for RAM regions we want to permanently reserve.
	*/
	static __init int is_reserve_region(efi_memory_desc_t *md)
	{
	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:
	case EFI_PERSISTENT_MEMORY:
	return 0;
	default:
	break;
	}
	return is_normal_ram(md);
	}

	static __init void reserve_regions(void)
	{
	efi_memory_desc_t *md;
	u64 paddr, npages, size;

	if (efi_enabled(EFI_DBG))
	pr_info("Processing EFI memory map:\n");

	for_each_efi_memory_desc(&memmap, md) {
	paddr = md->phys_addr;
	npages = md->num_pages;

	if (efi_enabled(EFI_DBG)) {
	char buf[64];

	pr_info(" 0x%012llx-0x%012llx %s",
	paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
	efi_md_typeattr_format(buf, sizeof(buf), md));
	}

	memrange_efi_to_native(&paddr, &npages);
	size = npages << PAGE_SHIFT;

	if (is_normal_ram(md))
	early_init_dt_add_memory_arch(paddr, size);

	if (is_reserve_region(md)) {
	memblock_reserve(paddr, size);
	if (efi_enabled(EFI_DBG))
	pr_cont("*");
	}

	if (efi_enabled(EFI_DBG))
	pr_cont("\n");
	}

	set_bit(EFI_MEMMAP, &efi.flags);
	}

	void __init efi_init(void)
	{
	struct efi_fdt_params params;

	/* Grab UEFI information placed in FDT by stub */
	if (!efi_get_fdt_params(&params))
	return;

	efi_system_table = params.system_table;

	memblock_reserve(params.mmap & PAGE_MASK,
	PAGE_ALIGN(params.mmap_size + (params.mmap & ~PAGE_MASK)));
	memmap.phys_map = params.mmap;
	memmap.map = early_memremap(params.mmap, params.mmap_size);
	if (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
	* proceeding if we cannot access it.
	*/
	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;

	if (uefi_init() < 0)
	return;

	reserve_regions();
	early_memunmap(memmap.map, params.mmap_size);
	}

	static bool __init efi_virtmap_init(void)
	{
	efi_memory_desc_t *md;

	init_new_context(NULL, &efi_mm);

	for_each_efi_memory_desc(&memmap, md) {
	pgprot_t prot;

	if (!(md->attribute & EFI_MEMORY_RUNTIME))
	continue;
	if (md->virt_addr == 0)
	return false;

	pr_info(" EFI remap 0x%016llx => %p\n",
	md->phys_addr, (void *)md->virt_addr);

	/*
	* Only regions of type EFI_RUNTIME_SERVICES_CODE need to be
	* executable, everything else can be mapped with the XN bits
	* set.
	*/
	if (!is_normal_ram(md))
	prot = __pgprot(PROT_DEVICE_nGnRE);
	else if (md->type == EFI_RUNTIME_SERVICES_CODE \|\|
	!PAGE_ALIGNED(md->phys_addr))
	prot = PAGE_KERNEL_EXEC;
	else
	prot = PAGE_KERNEL;

	create_pgd_mapping(&efi_mm, md->phys_addr, md->virt_addr,
	md->num_pages << EFI_PAGE_SHIFT,
	__pgprot(pgprot_val(prot) \| PTE_NG));
	}
	return true;
	}

	/*
	* Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
	* non-early mapping of the UEFI system table and virtual mappings for all
	* EFI_MEMORY_RUNTIME regions.
	*/
	static int __init arm64_enable_runtime_services(void)
	{
	u64 mapsize;

	if (!efi_enabled(EFI_BOOT)) {
	pr_info("EFI services will not be available.\n");
	return 0;
	}

	if (efi_runtime_disabled()) {
	pr_info("EFI runtime services will be disabled.\n");
	return 0;
	}

	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;

	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");
	return -ENOMEM;
	}
	set_bit(EFI_SYSTEM_TABLES, &efi.flags);

	if (!efi_virtmap_init()) {
	pr_err("No UEFI virtual mapping was installed -- runtime services will not be available\n");
	return -ENOMEM;
	}

	/* Set up runtime services function pointers */
	efi_native_runtime_setup();
	set_bit(EFI_RUNTIME_SERVICES, &efi.flags);

	efi.runtime_version = efi.systab->hdr.revision;

	return 0;
	}
	early_initcall(arm64_enable_runtime_services);

	static int __init arm64_dmi_init(void)
	{
	/*
	* On arm64, DMI depends on UEFI, and dmi_scan_machine() needs to
	* be called early because dmi_id_init(), which is an arch_initcall
	* itself, depends on dmi_scan_machine() having been called already.
	*/
	dmi_scan_machine();
	if (dmi_available)
	dmi_set_dump_stack_arch_desc();
	return 0;
	}
	core_initcall(arm64_dmi_init);

	static void efi_set_pgd(struct mm_struct *mm)
	{
	switch_mm(NULL, mm, NULL);
	}

	void efi_virtmap_load(void)
	{
	preempt_disable();
	efi_set_pgd(&efi_mm);
	}

	void efi_virtmap_unload(void)
	{
	efi_set_pgd(current->active_mm);
	preempt_enable();
	}

	/*
	* UpdateCapsule() depends on the system being shutdown via
	* ResetSystem().
	*/
	bool efi_poweroff_required(void)
	{
	return efi_enabled(EFI_RUNTIME_SERVICES);
	}