diff options
| -rw-r--r-- | arch/arm64/Kconfig | 113 |
1 files changed, 58 insertions, 55 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 0861a6f5ee4a..75c1a07abc72 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1082,9 +1082,65 @@ config RODATA_FULL_DEFAULT_ENABLED This requires the linear region to be mapped down to pages, which may adversely affect performance in some cases. +config ARM64_SW_TTBR0_PAN + bool "Emulate Privileged Access Never using TTBR0_EL1 switching" + help + Enabling this option prevents the kernel from accessing + user-space memory directly by pointing TTBR0_EL1 to a reserved + zeroed area and reserved ASID. The user access routines + restore the valid TTBR0_EL1 temporarily. + +menuconfig COMPAT + bool "Kernel support for 32-bit EL0" + depends on ARM64_4K_PAGES || EXPERT + select COMPAT_BINFMT_ELF if BINFMT_ELF + select HAVE_UID16 + select OLD_SIGSUSPEND3 + select COMPAT_OLD_SIGACTION + help + This option enables support for a 32-bit EL0 running under a 64-bit + kernel at EL1. AArch32-specific components such as system calls, + the user helper functions, VFP support and the ptrace interface are + handled appropriately by the kernel. + + If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware + that you will only be able to execute AArch32 binaries that were compiled + with page size aligned segments. + + If you want to execute 32-bit userspace applications, say Y. + +if COMPAT + +config KUSER_HELPERS + bool "Enable kuser helpers page for 32 bit applications" + default y + help + Warning: disabling this option may break 32-bit user programs. + + Provide kuser helpers to compat tasks. The kernel provides + helper code to userspace in read only form at a fixed location + to allow userspace to be independent of the CPU type fitted to + the system. This permits binaries to be run on ARMv4 through + to ARMv8 without modification. + + See Documentation/arm/kernel_user_helpers.txt for details. + + However, the fixed address nature of these helpers can be used + by ROP (return orientated programming) authors when creating + exploits. + + If all of the binaries and libraries which run on your platform + are built specifically for your platform, and make no use of + these helpers, then you can turn this option off to hinder + such exploits. However, in that case, if a binary or library + relying on those helpers is run, it will not function correctly. + + Say N here only if you are absolutely certain that you do not + need these helpers; otherwise, the safe option is to say Y. + + menuconfig ARMV8_DEPRECATED bool "Emulate deprecated/obsolete ARMv8 instructions" - depends on COMPAT depends on SYSCTL help Legacy software support may require certain instructions @@ -1150,13 +1206,7 @@ config SETEND_EMULATION If unsure, say Y endif -config ARM64_SW_TTBR0_PAN - bool "Emulate Privileged Access Never using TTBR0_EL1 switching" - help - Enabling this option prevents the kernel from accessing - user-space memory directly by pointing TTBR0_EL1 to a reserved - zeroed area and reserved ASID. The user access routines - restore the valid TTBR0_EL1 temporarily. +endif menu "ARMv8.1 architectural features" @@ -1479,53 +1529,6 @@ config DMI endmenu -config COMPAT - bool "Kernel support for 32-bit EL0" - depends on ARM64_4K_PAGES || EXPERT - select COMPAT_BINFMT_ELF if BINFMT_ELF - select HAVE_UID16 - select OLD_SIGSUSPEND3 - select COMPAT_OLD_SIGACTION - help - This option enables support for a 32-bit EL0 running under a 64-bit - kernel at EL1. AArch32-specific components such as system calls, - the user helper functions, VFP support and the ptrace interface are - handled appropriately by the kernel. - - If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware - that you will only be able to execute AArch32 binaries that were compiled - with page size aligned segments. - - If you want to execute 32-bit userspace applications, say Y. - -config KUSER_HELPERS - bool "Enable kuser helpers page for 32 bit applications." - depends on COMPAT - default y - help - Warning: disabling this option may break 32-bit user programs. - - Provide kuser helpers to compat tasks. The kernel provides - helper code to userspace in read only form at a fixed location - to allow userspace to be independent of the CPU type fitted to - the system. This permits binaries to be run on ARMv4 through - to ARMv8 without modification. - - See Documentation/arm/kernel_user_helpers.txt for details. - - However, the fixed address nature of these helpers can be used - by ROP (return orientated programming) authors when creating - exploits. - - If all of the binaries and libraries which run on your platform - are built specifically for your platform, and make no use of - these helpers, then you can turn this option off to hinder - such exploits. However, in that case, if a binary or library - relying on those helpers is run, it will not function correctly. - - Say N here only if you are absolutely certain that you do not - need these helpers; otherwise, the safe option is to say Y. - config SYSVIPC_COMPAT def_bool y depends on COMPAT && SYSVIPC |