From 1517c4facf2e66401394998dba1ee236fd261310 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Wed, 2 Dec 2020 13:15:58 +0000 Subject: [PATCH] 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: Mark Rutland Cc: Christoph Hellwig Cc: James Morse Cc: Will Deacon Link: https://lore.kernel.org/r/20201202131558.39270-13-mark.rutland@arm.com Signed-off-by: Catalin Marinas --- arch/arm64/Kconfig | 21 --------------------- arch/arm64/include/asm/cpucaps.h | 1 - arch/arm64/kernel/cpufeature.c | 11 ----------- 3 files changed, 33 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 6fae3ec..8d13b91 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -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 diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h index ab3bec7..a7242ef 100644 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -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 diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index d09bdc6..cf09bac8 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -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", -- 2.7.4