efi: vars: Remove deprecated 'efivars' sysfs interface

Commit 5d9db88 ("efi: Add support for a UEFI variable filesystem")
dated Oct 5, 2012, introduced a new efivarfs pseudo-filesystem to
replace the efivars sysfs interface that was used up to that point to
expose EFI variables to user space.

The main problem with the sysfs interface was that it only supported up
to 1024 bytes of payload per file, whereas the underlying variables
themselves are only bounded by a platform specific per-variable and
global limit that is typically much higher than 1024 bytes.

The deprecated sysfs interface is only enabled on x86 and Itanium, other
EFI enabled architectures only support the efivarfs pseudo-filesystem.

So let's finally rip off the band aid, and drop the old interface
entirely. This will make it easier to refactor and clean up the
underlying infrastructure that is shared between efivars, efivarfs and
efi-pstore, and is long overdue for a makeover.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

Documentation/x86/x86_64/uefi.rst

@@ -29,7 +29,7 @@ Mechanics
   be selected::
 
 	CONFIG_EFI=y
-	CONFIG_EFI_VARS=y or m		# optional
+	CONFIG_EFIVAR_FS=y or m		# optional
 
 - Create a VFAT partition on the disk
 - Copy the following to the VFAT partition:

arch/arm/configs/milbeaut_m10v_defconfig

@@ -44,7 +44,6 @@ CONFIG_ARM_CPUIDLE=y
 CONFIG_VFP=y
 CONFIG_NEON=y
 CONFIG_KERNEL_MODE_NEON=y
-CONFIG_EFI_VARS=m
 CONFIG_EFI_CAPSULE_LOADER=m
 CONFIG_ARM_CRYPTO=y
 CONFIG_CRYPTO_SHA1_ARM_NEON=m

arch/ia64/configs/bigsur_defconfig

@@ -10,7 +10,6 @@ CONFIG_SMP=y
 CONFIG_NR_CPUS=2
 CONFIG_PREEMPT=y
 CONFIG_IA64_PALINFO=y
-CONFIG_EFI_VARS=y
 CONFIG_BINFMT_MISC=m
 CONFIG_ACPI_BUTTON=m
 CONFIG_ACPI_FAN=m

arch/ia64/configs/generic_defconfig

@@ -21,7 +21,6 @@ CONFIG_IA64_MCA_RECOVERY=y
 CONFIG_IA64_PALINFO=y
 CONFIG_KEXEC=y
 CONFIG_CRASH_DUMP=y
-CONFIG_EFI_VARS=y
 CONFIG_BINFMT_MISC=m
 CONFIG_ACPI_BUTTON=m
 CONFIG_ACPI_FAN=m

arch/ia64/configs/gensparse_defconfig

@@ -18,7 +18,6 @@ CONFIG_HOTPLUG_CPU=y
 CONFIG_SPARSEMEM_MANUAL=y
 CONFIG_IA64_MCA_RECOVERY=y
 CONFIG_IA64_PALINFO=y
-CONFIG_EFI_VARS=y
 CONFIG_BINFMT_MISC=m
 CONFIG_ACPI_BUTTON=m
 CONFIG_ACPI_FAN=m

arch/ia64/configs/tiger_defconfig

@@ -23,7 +23,6 @@ CONFIG_FORCE_CPEI_RETARGET=y
 CONFIG_IA64_MCA_RECOVERY=y
 CONFIG_IA64_PALINFO=y
 CONFIG_KEXEC=y
-CONFIG_EFI_VARS=y
 CONFIG_BINFMT_MISC=m
 CONFIG_ACPI_BUTTON=m
 CONFIG_ACPI_FAN=m

arch/ia64/configs/zx1_defconfig

@@ -12,7 +12,6 @@ CONFIG_FLATMEM_MANUAL=y
 CONFIG_IA64_MCA_RECOVERY=y
 CONFIG_IA64_PALINFO=y
 CONFIG_CRASH_DUMP=y
-CONFIG_EFI_VARS=y
 CONFIG_BINFMT_MISC=y
 CONFIG_HOTPLUG_PCI=y
 CONFIG_HOTPLUG_PCI_ACPI=y

arch/x86/configs/i386_defconfig

@@ -135,7 +135,6 @@ CONFIG_DEVTMPFS=y
 CONFIG_DEVTMPFS_MOUNT=y
 CONFIG_DEBUG_DEVRES=y
 CONFIG_CONNECTOR=y
-CONFIG_EFI_VARS=y
 CONFIG_EFI_CAPSULE_LOADER=y
 CONFIG_BLK_DEV_LOOP=y
 CONFIG_VIRTIO_BLK=y

arch/x86/configs/x86_64_defconfig

@@ -134,7 +134,6 @@ CONFIG_DEVTMPFS=y
 CONFIG_DEVTMPFS_MOUNT=y
 CONFIG_DEBUG_DEVRES=y
 CONFIG_CONNECTOR=y
-CONFIG_EFI_VARS=y
 CONFIG_BLK_DEV_LOOP=y
 CONFIG_VIRTIO_BLK=y
 CONFIG_BLK_DEV_SD=y

drivers/firmware/efi/Kconfig

@@ -2,18 +2,6 @@
 menu "EFI (Extensible Firmware Interface) Support"
 	depends on EFI
 
-config EFI_VARS
-	tristate "EFI Variable Support via sysfs"
-	depends on EFI && (X86 || IA64)
-	default n
-	help
-	  If you say Y here, you are able to get EFI (Extensible Firmware
-	  Interface) variable information via sysfs.  You may read,
-	  write, create, and destroy EFI variables through this interface.
-	  Note that this driver is only retained for compatibility with
-	  legacy users: new users should use the efivarfs filesystem
-	  instead.
-
 config EFI_ESRT
 	bool
 	depends on EFI && !IA64

drivers/firmware/efi/Makefile

@@ -17,7 +17,6 @@ ifneq ($(CONFIG_EFI_CAPSULE_LOADER),)
 obj-$(CONFIG_EFI)			+= capsule.o
 endif
 obj-$(CONFIG_EFI_PARAMS_FROM_FDT)	+= fdtparams.o
-obj-$(CONFIG_EFI_VARS)			+= efivars.o
 obj-$(CONFIG_EFI_ESRT)			+= esrt.o
 obj-$(CONFIG_EFI_VARS_PSTORE)		+= efi-pstore.o
 obj-$(CONFIG_UEFI_CPER)			+= cper.o