efi: Export EFI runtime memory mapping to sysfs (926172d4) · Commits · e / devices / android_kernel_oneplus_sm7250

Documentation/ABI/testing/sysfs-firmware-efi-runtime-map

0 → 100644

+34 −0

Original line number	Original line	Diff line number	Diff line
			What: /sys/firmware/efi/runtime-map/
			Date: December 2013
			Contact: Dave Young <dyoung@redhat.com>
			Description: Switching efi runtime services to virtual mode requires
			that all efi memory ranges which have the runtime attribute
			bit set to be mapped to virtual addresses.

			The efi runtime services can only be switched to virtual
			mode once without rebooting. The kexec kernel must maintain
			the same physical to virtual address mappings as the first
			kernel. The mappings are exported to sysfs so userspace tools
			can reassemble them and pass them into the kexec kernel.

			/sys/firmware/efi/runtime-map/ is the directory the kernel
			exports that information in.

			subdirectories are named with the number of the memory range:

			/sys/firmware/efi/runtime-map/0
			/sys/firmware/efi/runtime-map/1
			/sys/firmware/efi/runtime-map/2
			/sys/firmware/efi/runtime-map/3
			...

			Each subdirectory contains five files:

			attribute : The attributes of the memory range.
			num_pages : The size of the memory range in pages.
			phys_addr : The physical address of the memory range.
			type : The type of the memory range.
			virt_addr : The virtual address of the memory range.

			Above values are all hexadecimal numbers with the '0x' prefix.
			Users: Kexec

arch/x86/platform/efi/efi.c

+43 −3

Original line number	Original line	Diff line number	Diff line
	@@ -76,6 +76,9 @@ static __initdata efi_config_table_type_t arch_tables[] = {
	{NULL_GUID, NULL, NULL},		{NULL_GUID, NULL, NULL},
	};		};

			static void *efi_runtime_map;
			static int nr_efi_runtime_map;

	/*		/*
	* Returns 1 if 'facility' is enabled, 0 otherwise.		* Returns 1 if 'facility' is enabled, 0 otherwise.
	*/		*/
	@@ -824,6 +827,39 @@ static void __init get_systab_virt_addr(efi_memory_desc_t *md)
	}		}
	}		}

			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 = q;
			nr_efi_runtime_map = count;
			efi_runtime_map_setup(efi_runtime_map, nr_efi_runtime_map,
			boot_params.efi_info.efi_memdesc_size);

			return 0;
			out:
			kfree(q);
			return -ENOMEM;
			}

	/*		/*
	* Map efi memory ranges for runtime serivce and update new_memmap with virtual		* Map efi memory ranges for runtime serivce and update new_memmap with virtual
	* addresses.		* addresses.
	@@ -849,7 +885,7 @@ static void * __init efi_map_regions(int *count)
	tmp = krealloc(new_memmap, (count + 1) memmap.desc_size,		tmp = krealloc(new_memmap, (count + 1) memmap.desc_size,
	GFP_KERNEL);		GFP_KERNEL);
	if (!tmp)		if (!tmp)
	goto out_krealloc;		goto out;
	new_memmap = tmp;		new_memmap = tmp;
	memcpy(new_memmap + (count memmap.desc_size), md,		memcpy(new_memmap + (count memmap.desc_size), md,
	memmap.desc_size);		memmap.desc_size);
	@@ -857,7 +893,7 @@ static void * __init efi_map_regions(int *count)
	}		}

	return new_memmap;		return new_memmap;
	out_krealloc:		out:
	kfree(new_memmap);		kfree(new_memmap);
	return NULL;		return NULL;
	}		}
	@@ -883,7 +919,7 @@ void __init efi_enter_virtual_mode(void)
	{		{
	efi_status_t status;		efi_status_t status;
	void *new_memmap = NULL;		void *new_memmap = NULL;
	int count = 0;		int err, count = 0;

	efi.systab = NULL;		efi.systab = NULL;

	@@ -904,6 +940,10 @@ void __init efi_enter_virtual_mode(void)
	return;		return;
	}		}

			err = save_runtime_map();
			if (err)
			pr_err("Error saving runtime map, efi runtime on kexec non-functional!!\n");

	BUG_ON(!efi.systab);		BUG_ON(!efi.systab);

	efi_setup_page_tables();		efi_setup_page_tables();

drivers/firmware/efi/Kconfig

+11 −0

Original line number	Original line	Diff line number	Diff line
	@@ -39,4 +39,15 @@ config EFI_VARS_PSTORE_DEFAULT_DISABLE
	config UEFI_CPER		config UEFI_CPER
	def_bool n		def_bool n

			config EFI_RUNTIME_MAP
			bool "Export efi runtime maps to sysfs"
			depends on X86 && EFI && KEXEC
			default y
			help
			Export efi runtime memory maps to /sys/firmware/efi/runtime-map.
			That memory map is used for example by kexec to set up efi virtual
			mapping the 2nd kernel, but can also be used for debugging purposes.

			See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.

	endmenu		endmenu

drivers/firmware/efi/Makefile

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -5,3 +5,4 @@ obj-y += efi.o vars.o
	obj-$(CONFIG_EFI_VARS) += efivars.o		obj-$(CONFIG_EFI_VARS) += efivars.o
	obj-$(CONFIG_EFI_VARS_PSTORE) += efi-pstore.o		obj-$(CONFIG_EFI_VARS_PSTORE) += efi-pstore.o
	obj-$(CONFIG_UEFI_CPER) += cper.o		obj-$(CONFIG_UEFI_CPER) += cper.o
			obj-$(CONFIG_EFI_RUNTIME_MAP) += runtime-map.o

drivers/firmware/efi/efi.c

+4 −0

Original line number	Original line	Diff line number	Diff line
	@@ -167,6 +167,10 @@ static int __init efisubsys_init(void)
	goto err_unregister;		goto err_unregister;
	}		}

			error = efi_runtime_map_init(efi_kobj);
			if (error)
			goto err_remove_group;

	/* and the standard mountpoint for efivarfs */		/* and the standard mountpoint for efivarfs */
	efivars_kobj = kobject_create_and_add("efivars", efi_kobj);		efivars_kobj = kobject_create_and_add("efivars", efi_kobj);
	if (!efivars_kobj) {		if (!efivars_kobj) {