arm64: kconfig: group the v8.1 features together (0e4a0709) · Commits · 戴 / test

arch/arm64/Kconfig

+47 −43

Original line number	Diff line number	Diff line
		@@ -481,23 +481,6 @@ config ARM64_VA_BITS
		default 42 if ARM64_VA_BITS_42
		default 48 if ARM64_VA_BITS_48

		config ARM64_HW_AFDBM
		bool "Support for hardware updates of the Access and Dirty page flags"
		default y
		help
		The ARMv8.1 architecture extensions introduce support for
		hardware updates of the access and dirty information in page
		table entries. When enabled in TCR_EL1 (HA and HD bits) on
		capable processors, accesses to pages with PTE_AF cleared will
		set this bit instead of raising an access flag fault.
		Similarly, writes to read-only pages with the DBM bit set will
		clear the read-only bit (AP[2]) instead of raising a
		permission fault.

		Kernels built with this configuration option enabled continue
		to work on pre-ARMv8.1 hardware and the performance impact is
		minimal. If unsure, say Y.

		config CPU_BIG_ENDIAN
		bool "Build big-endian kernel"
		help
		@@ -605,32 +588,6 @@ config FORCE_MAX_ZONEORDER
		default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE)
		default "11"

		config ARM64_PAN
		bool "Enable support for Privileged Access Never (PAN)"
		default y
		help
		Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
		prevents the kernel or hypervisor from accessing user-space (EL0)
		memory directly.

		Choosing this option will cause any unprotected (not using
		copy_to_user et al) memory access to fail with a permission fault.

		The feature is detected at runtime, and will remain as a 'nop'
		instruction if the cpu does not implement the feature.

		config ARM64_LSE_ATOMICS
		bool "ARMv8.1 atomic instructions"
		help
		As part of the Large System Extensions, ARMv8.1 introduces new
		atomic instructions that are designed specifically to scale in
		very large systems.

		Say Y here to make use of these instructions for the in-kernel
		atomic routines. This incurs a small overhead on CPUs that do
		not support these instructions and requires the kernel to be
		built with binutils >= 2.25.

		menuconfig ARMV8_DEPRECATED
		bool "Emulate deprecated/obsolete ARMv8 instructions"
		depends on COMPAT
		@@ -698,6 +655,53 @@ config SETEND_EMULATION
		If unsure, say Y
		endif

		menu "ARMv8.1 architectural features"

		config ARM64_HW_AFDBM
		bool "Support for hardware updates of the Access and Dirty page flags"
		default y
		help
		The ARMv8.1 architecture extensions introduce support for
		hardware updates of the access and dirty information in page
		table entries. When enabled in TCR_EL1 (HA and HD bits) on
		capable processors, accesses to pages with PTE_AF cleared will
		set this bit instead of raising an access flag fault.
		Similarly, writes to read-only pages with the DBM bit set will
		clear the read-only bit (AP[2]) instead of raising a
		permission fault.

		Kernels built with this configuration option enabled continue
		to work on pre-ARMv8.1 hardware and the performance impact is
		minimal. If unsure, say Y.

		config ARM64_PAN
		bool "Enable support for Privileged Access Never (PAN)"
		default y
		help
		Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
		prevents the kernel or hypervisor from accessing user-space (EL0)
		memory directly.

		Choosing this option will cause any unprotected (not using
		copy_to_user et al) memory access to fail with a permission fault.

		The feature is detected at runtime, and will remain as a 'nop'
		instruction if the cpu does not implement the feature.

		config ARM64_LSE_ATOMICS
		bool "Atomic instructions"
		help
		As part of the Large System Extensions, ARMv8.1 introduces new
		atomic instructions that are designed specifically to scale in
		very large systems.

		Say Y here to make use of these instructions for the in-kernel
		atomic routines. This incurs a small overhead on CPUs that do
		not support these instructions and requires the kernel to be
		built with binutils >= 2.25.

		endmenu

		endmenu

		menu "Boot options"

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