arch/x86/platform/efi/quirks.c - linux - Git at Google

 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
 #include <linux/time.h>
 #include <linux/types.h>
 #include <linux/efi.h>
 #include <linux/slab.h>
 #include <linux/memblock.h>
 #include <linux/bootmem.h>
 #include <linux/acpi.h>
 #include <asm/efi.h>
 #include <asm/uv/uv.h>

 #define EFI_MIN_RESERVE 5120

 #define EFI_DUMMY_GUID \
 	EFI_GUID(0x4424ac57, 0xbe4b, 0x47dd, 0x9e, 0x97, 0xed, 0x50, 0xf0, 0x9f, 0x92, 0xa9)

 static efi_char16_t efi_dummy_name[6] = { 'D', 'U', 'M', 'M', 'Y', 0 };

 static bool efi_no_storage_paranoia;

 /*
  * Some firmware implementations refuse to boot if there's insufficient
  * space in the variable store. The implementation of garbage collection
  * in some FW versions causes stale (deleted) variables to take up space
  * longer than intended and space is only freed once the store becomes
  * almost completely full.
  *
  * Enabling this option disables the space checks in
  * efi_query_variable_store() and forces garbage collection.
  *
  * Only enable this option if deleting EFI variables does not free up
  * space in your variable store, e.g. if despite deleting variables
  * you're unable to create new ones.
  */
 static int __init setup_storage_paranoia(char *arg)
 {
 	efi_no_storage_paranoia = true;
 	return 0;
 }
 early_param("efi_no_storage_paranoia", setup_storage_paranoia);

 /*
  * Deleting the dummy variable which kicks off garbage collection
 */
 void efi_delete_dummy_variable(void)
 {
 	efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
 			 EFI_VARIABLE_NON_VOLATILE |
 			 EFI_VARIABLE_BOOTSERVICE_ACCESS |
 			 EFI_VARIABLE_RUNTIME_ACCESS,
 			 0, NULL);
 }

 /*
  * Some firmware implementations refuse to boot if there's insufficient space
  * in the variable store. Ensure that we never use more than a safe limit.
  *
  * Return EFI_SUCCESS if it is safe to write 'size' bytes to the variable
  * store.
  */
 efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
 {
 	efi_status_t status;
 	u64 storage_size, remaining_size, max_size;

 	if (!(attributes & EFI_VARIABLE_NON_VOLATILE))
 		return 0;

 	status = efi.query_variable_info(attributes, &storage_size,
 					 &remaining_size, &max_size);
 	if (status != EFI_SUCCESS)
 		return status;

 	/*
 	 * We account for that by refusing the write if permitting it would
 	 * reduce the available space to under 5KB. This figure was provided by
 	 * Samsung, so should be safe.
 	 */
 	if ((remaining_size - size < EFI_MIN_RESERVE) &&
 		!efi_no_storage_paranoia) {

 		/*
 		 * Triggering garbage collection may require that the firmware
 		 * generate a real EFI_OUT_OF_RESOURCES error. We can force
 		 * that by attempting to use more space than is available.
 		 */
 		unsigned long dummy_size = remaining_size + 1024;
 		void *dummy = kzalloc(dummy_size, GFP_ATOMIC);

 		if (!dummy)
 			return EFI_OUT_OF_RESOURCES;

 		status = efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
 					  EFI_VARIABLE_NON_VOLATILE |
 					  EFI_VARIABLE_BOOTSERVICE_ACCESS |
 					  EFI_VARIABLE_RUNTIME_ACCESS,
 					  dummy_size, dummy);

 		if (status == EFI_SUCCESS) {
 			/*
 			 * This should have failed, so if it didn't make sure
 			 * that we delete it...
 			 */
 			efi_delete_dummy_variable();
 		}

 		kfree(dummy);

 		/*
 		 * The runtime code may now have triggered a garbage collection
 		 * run, so check the variable info again
 		 */
 		status = efi.query_variable_info(attributes, &storage_size,
 						 &remaining_size, &max_size);

 		if (status != EFI_SUCCESS)
 			return status;

 		/*
 		 * There still isn't enough room, so return an error
 		 */
 		if (remaining_size - size < EFI_MIN_RESERVE)
 			return EFI_OUT_OF_RESOURCES;
 	}

 	return EFI_SUCCESS;
 }
 EXPORT_SYMBOL_GPL(efi_query_variable_store);

 /*
  * The UEFI specification makes it clear that the operating system is free to do
  * whatever it wants with boot services code after ExitBootServices() has been
  * called. Ignoring this recommendation a significant bunch of EFI implementations
  * continue calling into boot services code (SetVirtualAddressMap). In order to
  * work around such buggy implementations we reserve boot services region during
  * EFI init and make sure it stays executable. Then, after SetVirtualAddressMap(), it
 * is discarded.
 */
 void __init efi_reserve_boot_services(void)
 {
 	void *p;

 	for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 		efi_memory_desc_t *md = p;
 		u64 start = md->phys_addr;
 		u64 size = md->num_pages << EFI_PAGE_SHIFT;

 		if (md->type != EFI_BOOT_SERVICES_CODE &&
 		    md->type != EFI_BOOT_SERVICES_DATA)
 			continue;
 		/* Only reserve where possible:
 		 * - Not within any already allocated areas
 		 * - Not over any memory area (really needed, if above?)
 		 * - Not within any part of the kernel
 		 * - Not the bios reserved area
 		*/
 		if ((start + size > __pa_symbol(_text)
 				&& start <= __pa_symbol(_end)) ||
 			!e820_all_mapped(start, start+size, E820_RAM) ||
 			memblock_is_region_reserved(start, size)) {
 			/* Could not reserve, skip it */
 			md->num_pages = 0;
 			memblock_dbg("Could not reserve boot range [0x%010llx-0x%010llx]\n",
 				     start, start+size-1);
 		} else
 			memblock_reserve(start, size);
 	}
 }

 void __init efi_free_boot_services(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;

 		if (md->type != EFI_BOOT_SERVICES_CODE &&
 		    md->type != EFI_BOOT_SERVICES_DATA)
 			continue;

 		/* Could not reserve boot area */
 		if (!size)
 			continue;

 		free_bootmem_late(start, size);
 	}

 	efi_unmap_memmap();
 }

 /*
  * 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.
  */
 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_memunmap(tablep, nr_tables * sz);

 out_memremap:
 	early_memunmap(data, sizeof(*data));
 out:
 	return ret;
 }

 void __init efi_apply_memmap_quirks(void)
 {
 	/*
 	 * Once setup is done earlier, unmap the EFI memory map on mismatched
 	 * firmware/kernel architectures since there is no support for runtime
 	 * services.
 	 */
 	if (!efi_runtime_supported()) {
 		pr_info("efi: Setup done, disabling due to 32/64-bit mismatch\n");
 		efi_unmap_memmap();
 	}

 	/*
 	 * UV doesn't support the new EFI pagetable mapping yet.
 	 */
 	if (is_uv_system())
 		set_bit(EFI_OLD_MEMMAP, &efi.flags);
 }

 /*
  * For most modern platforms the preferred method of powering off is via
  * ACPI. However, there are some that are known to require the use of
  * EFI runtime services and for which ACPI does not work at all.
  *
  * Using EFI is a last resort, to be used only if no other option
  * exists.
  */
 bool efi_reboot_required(void)
 {
 	if (!acpi_gbl_reduced_hardware)
 		return false;

 	efi_reboot_quirk_mode = EFI_RESET_WARM;
 	return true;
 }

 bool efi_poweroff_required(void)
 {
 	return !!acpi_gbl_reduced_hardware;
 }
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/string.h>
	#include <linux/time.h>
	#include <linux/types.h>
	#include <linux/efi.h>
	#include <linux/slab.h>
	#include <linux/memblock.h>
	#include <linux/bootmem.h>
	#include <linux/acpi.h>
	#include <asm/efi.h>
	#include <asm/uv/uv.h>

	#define EFI_MIN_RESERVE 5120

	#define EFI_DUMMY_GUID \
	EFI_GUID(0x4424ac57, 0xbe4b, 0x47dd, 0x9e, 0x97, 0xed, 0x50, 0xf0, 0x9f, 0x92, 0xa9)

	static efi_char16_t efi_dummy_name[6] = { 'D', 'U', 'M', 'M', 'Y', 0 };

	static bool efi_no_storage_paranoia;

	/*
	* Some firmware implementations refuse to boot if there's insufficient
	* space in the variable store. The implementation of garbage collection
	* in some FW versions causes stale (deleted) variables to take up space
	* longer than intended and space is only freed once the store becomes
	* almost completely full.
	*
	* Enabling this option disables the space checks in
	* efi_query_variable_store() and forces garbage collection.
	*
	* Only enable this option if deleting EFI variables does not free up
	* space in your variable store, e.g. if despite deleting variables
	* you're unable to create new ones.
	*/
	static int __init setup_storage_paranoia(char *arg)
	{
	efi_no_storage_paranoia = true;
	return 0;
	}
	early_param("efi_no_storage_paranoia", setup_storage_paranoia);

	/*
	* Deleting the dummy variable which kicks off garbage collection
	*/
	void efi_delete_dummy_variable(void)
	{
	efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
	EFI_VARIABLE_NON_VOLATILE \|
	EFI_VARIABLE_BOOTSERVICE_ACCESS \|
	EFI_VARIABLE_RUNTIME_ACCESS,
	0, NULL);
	}

	/*
	* Some firmware implementations refuse to boot if there's insufficient space
	* in the variable store. Ensure that we never use more than a safe limit.
	*
	* Return EFI_SUCCESS if it is safe to write 'size' bytes to the variable
	* store.
	*/
	efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
	{
	efi_status_t status;
	u64 storage_size, remaining_size, max_size;

	if (!(attributes & EFI_VARIABLE_NON_VOLATILE))
	return 0;

	status = efi.query_variable_info(attributes, &storage_size,
	&remaining_size, &max_size);
	if (status != EFI_SUCCESS)
	return status;

	/*
	* We account for that by refusing the write if permitting it would
	* reduce the available space to under 5KB. This figure was provided by
	* Samsung, so should be safe.
	*/
	if ((remaining_size - size < EFI_MIN_RESERVE) &&
	!efi_no_storage_paranoia) {

	/*
	* Triggering garbage collection may require that the firmware
	* generate a real EFI_OUT_OF_RESOURCES error. We can force
	* that by attempting to use more space than is available.
	*/
	unsigned long dummy_size = remaining_size + 1024;
	void *dummy = kzalloc(dummy_size, GFP_ATOMIC);

	if (!dummy)
	return EFI_OUT_OF_RESOURCES;

	status = efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
	EFI_VARIABLE_NON_VOLATILE \|
	EFI_VARIABLE_BOOTSERVICE_ACCESS \|
	EFI_VARIABLE_RUNTIME_ACCESS,
	dummy_size, dummy);

	if (status == EFI_SUCCESS) {
	/*
	* This should have failed, so if it didn't make sure
	* that we delete it...
	*/
	efi_delete_dummy_variable();
	}

	kfree(dummy);

	/*
	* The runtime code may now have triggered a garbage collection
	* run, so check the variable info again
	*/
	status = efi.query_variable_info(attributes, &storage_size,
	&remaining_size, &max_size);

	if (status != EFI_SUCCESS)
	return status;

	/*
	* There still isn't enough room, so return an error
	*/
	if (remaining_size - size < EFI_MIN_RESERVE)
	return EFI_OUT_OF_RESOURCES;
	}

	return EFI_SUCCESS;
	}
	EXPORT_SYMBOL_GPL(efi_query_variable_store);

	/*
	* The UEFI specification makes it clear that the operating system is free to do
	* whatever it wants with boot services code after ExitBootServices() has been
	* called. Ignoring this recommendation a significant bunch of EFI implementations
	* continue calling into boot services code (SetVirtualAddressMap). In order to
	* work around such buggy implementations we reserve boot services region during
	* EFI init and make sure it stays executable. Then, after SetVirtualAddressMap(), it
	* is discarded.
	*/
	void __init efi_reserve_boot_services(void)
	{
	void *p;

	for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
	efi_memory_desc_t *md = p;
	u64 start = md->phys_addr;
	u64 size = md->num_pages << EFI_PAGE_SHIFT;

	if (md->type != EFI_BOOT_SERVICES_CODE &&
	md->type != EFI_BOOT_SERVICES_DATA)
	continue;
	/* Only reserve where possible:
	* - Not within any already allocated areas
	* - Not over any memory area (really needed, if above?)
	* - Not within any part of the kernel
	* - Not the bios reserved area
	*/
	if ((start + size > __pa_symbol(_text)
	&& start <= __pa_symbol(_end)) \|\|
	!e820_all_mapped(start, start+size, E820_RAM) \|\|
	memblock_is_region_reserved(start, size)) {
	/* Could not reserve, skip it */
	md->num_pages = 0;
	memblock_dbg("Could not reserve boot range [0x%010llx-0x%010llx]\n",
	start, start+size-1);
	} else
	memblock_reserve(start, size);
	}
	}

	void __init efi_free_boot_services(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;

	if (md->type != EFI_BOOT_SERVICES_CODE &&
	md->type != EFI_BOOT_SERVICES_DATA)
	continue;

	/* Could not reserve boot area */
	if (!size)
	continue;

	free_bootmem_late(start, size);
	}

	efi_unmap_memmap();
	}

	/*
	* 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.
	*/
	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_memunmap(tablep, nr_tables * sz);

	out_memremap:
	early_memunmap(data, sizeof(*data));
	out:
	return ret;
	}

	void __init efi_apply_memmap_quirks(void)
	{
	/*
	* Once setup is done earlier, unmap the EFI memory map on mismatched
	* firmware/kernel architectures since there is no support for runtime
	* services.
	*/
	if (!efi_runtime_supported()) {
	pr_info("efi: Setup done, disabling due to 32/64-bit mismatch\n");
	efi_unmap_memmap();
	}

	/*
	* UV doesn't support the new EFI pagetable mapping yet.
	*/
	if (is_uv_system())
	set_bit(EFI_OLD_MEMMAP, &efi.flags);
	}

	/*
	* For most modern platforms the preferred method of powering off is via
	* ACPI. However, there are some that are known to require the use of
	* EFI runtime services and for which ACPI does not work at all.
	*
	* Using EFI is a last resort, to be used only if no other option
	* exists.
	*/
	bool efi_reboot_required(void)
	{
	if (!acpi_gbl_reduced_hardware)
	return false;

	efi_reboot_quirk_mode = EFI_RESET_WARM;
	return true;
	}

	bool efi_poweroff_required(void)
	{
	return !!acpi_gbl_reduced_hardware;
	}