Commit 1517c4fa authored by Mark Rutland's avatar Mark Rutland Committed by Catalin Marinas
Browse files

arm64: uaccess: remove vestigal UAO support 



Now that arm64 no longer uses UAO, remove the vestigal feature detection
code and Kconfig text.

Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201202131558.39270-13-mark.rutland@arm.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 7cf283c7

arch/arm64/Kconfig

+0 −21
Original line number Diff line number Diff line
@@ -1427,27 +1427,6 @@ endmenu 


menu "ARMv8.2 architectural features"



config ARM64_UAO

	bool "Enable support for User Access Override (UAO)"

	default y

	help

	  User Access Override (UAO; part of the ARMv8.2 Extensions)

	  causes the 'unprivileged' variant of the load/store instructions to

	  be overridden to be privileged.



	  This option changes get_user() and friends to use the 'unprivileged'

	  variant of the load/store instructions. This ensures that user-space

	  really did have access to the supplied memory. When addr_limit is

	  set to kernel memory the UAO bit will be set, allowing privileged

	  access to kernel memory.



	  Choosing this option will cause copy_to_user() et al to use user-space

	  memory permissions.



	  The feature is detected at runtime, the kernel will use the

	  regular load/store instructions if the cpu does not implement the

	  feature.



config ARM64_PMEM

	bool "Enable support for persistent memory"

	select ARCH_HAS_PMEM_API

arch/arm64/include/asm/cpucaps.h

+0 −1
Original line number Diff line number Diff line
@@ -16,7 +16,6 @@ 
#define ARM64_WORKAROUND_CAVIUM_23154		6

#define ARM64_WORKAROUND_834220			7

#define ARM64_HAS_NO_HW_PREFETCH		8

#define ARM64_HAS_UAO				9

#define ARM64_HAS_VIRT_HOST_EXTN		11

#define ARM64_WORKAROUND_CAVIUM_27456		12

#define ARM64_HAS_32BIT_EL0			13

arch/arm64/kernel/cpufeature.c

+0 −11
Original line number Diff line number Diff line
@@ -1764,17 +1764,6 @@ static const struct arm64_cpu_capabilities arm64_features[] = { 
		.type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE,

		.matches = has_no_hw_prefetch,

	},

#ifdef CONFIG_ARM64_UAO

	{

		.desc = "User Access Override",

		.capability = ARM64_HAS_UAO,

		.type = ARM64_CPUCAP_SYSTEM_FEATURE,

		.matches = has_cpuid_feature,

		.sys_reg = SYS_ID_AA64MMFR2_EL1,

		.field_pos = ID_AA64MMFR2_UAO_SHIFT,

		.min_field_value = 1,

	},

#endif /* CONFIG_ARM64_UAO */

#ifdef CONFIG_ARM64_VHE

	{

		.desc = "Virtualization Host Extensions",