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Commit a0998eb1 authored by Dave Young's avatar Dave Young Committed by Matt Fleming
Browse files

efi: Export more EFI table variables to sysfs 



Export fw_vendor, runtime and config table physical addresses to
/sys/firmware/efi/{fw_vendor,runtime,config_table} because kexec kernels
need them.

From EFI spec these 3 variables will be updated to virtual address after
entering virtual mode. But kernel startup code will need the physical
address.

Signed-off-by: default avatarDave Young <dyoung@redhat.com>
Tested-by: default avatarToshi Kani <toshi.kani@hp.com>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
parent 481f75c0

Documentation/ABI/testing/sysfs-firmware-efi

0 → 100644
+20 −0
Original line number Diff line number Diff line 
What:		/sys/firmware/efi/fw_vendor

Date:		December 2013

Contact:	Dave Young <dyoung@redhat.com>

Description:	It shows the physical address of firmware vendor field in the

		EFI system table.

Users:		Kexec



What:		/sys/firmware/efi/runtime

Date:		December 2013

Contact:	Dave Young <dyoung@redhat.com>

Description:	It shows the physical address of runtime service table entry in

		the EFI system table.

Users:		Kexec



What:		/sys/firmware/efi/config_table

Date:		December 2013

Contact:	Dave Young <dyoung@redhat.com>

Description:	It shows the physical address of config table entry in the EFI

		system table.

Users:		Kexec

arch/x86/platform/efi/efi.c

+4 −0
Original line number Diff line number Diff line
@@ -653,6 +653,10 @@ 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

	 */

drivers/firmware/efi/efi.c

+40 −1
Original line number Diff line number Diff line
@@ -32,6 +32,9 @@ struct efi __read_mostly efi = { 
	.hcdp       = EFI_INVALID_TABLE_ADDR,

	.uga        = EFI_INVALID_TABLE_ADDR,

	.uv_systab  = EFI_INVALID_TABLE_ADDR,

	.fw_vendor  = EFI_INVALID_TABLE_ADDR,

	.runtime    = EFI_INVALID_TABLE_ADDR,

	.config_table  = EFI_INVALID_TABLE_ADDR,

};

EXPORT_SYMBOL(efi);
@@ -71,13 +74,49 @@ static ssize_t systab_show(struct kobject *kobj, 
static struct kobj_attribute efi_attr_systab =

			__ATTR(systab, 0400, systab_show, NULL);



#define EFI_FIELD(var) efi.var



#define EFI_ATTR_SHOW(name) \

static ssize_t name##_show(struct kobject *kobj, \

				struct kobj_attribute *attr, char *buf) \

{ \

	return sprintf(buf, "0x%lx\n", EFI_FIELD(name)); \

}



EFI_ATTR_SHOW(fw_vendor);

EFI_ATTR_SHOW(runtime);

EFI_ATTR_SHOW(config_table);



static struct kobj_attribute efi_attr_fw_vendor = __ATTR_RO(fw_vendor);

static struct kobj_attribute efi_attr_runtime = __ATTR_RO(runtime);

static struct kobj_attribute efi_attr_config_table = __ATTR_RO(config_table);



static struct attribute *efi_subsys_attrs[] = {

	&efi_attr_systab.attr,

	NULL,	/* maybe more in the future? */

	&efi_attr_fw_vendor.attr,

	&efi_attr_runtime.attr,

	&efi_attr_config_table.attr,

	NULL,

};



static umode_t efi_attr_is_visible(struct kobject *kobj,

				   struct attribute *attr, int n)

{

	umode_t mode = attr->mode;



	if (attr == &efi_attr_fw_vendor.attr)

		return (efi.fw_vendor == EFI_INVALID_TABLE_ADDR) ? 0 : mode;

	else if (attr == &efi_attr_runtime.attr)

		return (efi.runtime == EFI_INVALID_TABLE_ADDR) ? 0 : mode;

	else if (attr == &efi_attr_config_table.attr)

		return (efi.config_table == EFI_INVALID_TABLE_ADDR) ? 0 : mode;



	return mode;

}



static struct attribute_group efi_subsys_attr_group = {

	.attrs = efi_subsys_attrs,

	.is_visible = efi_attr_is_visible,

};



static struct efivars generic_efivars;

include/linux/efi.h

+3 −0
Original line number Diff line number Diff line
@@ -556,6 +556,9 @@ extern struct efi { 
	unsigned long hcdp;		/* HCDP table */

	unsigned long uga;		/* UGA table */

	unsigned long uv_systab;	/* UV system table */

	unsigned long fw_vendor;	/* fw_vendor */

	unsigned long runtime;		/* runtime table */

	unsigned long config_table;	/* config tables */

	efi_get_time_t *get_time;

	efi_set_time_t *set_time;

	efi_get_wakeup_time_t *get_wakeup_time;