diff options
Diffstat (limited to 'arch/arm64/Kconfig')
| -rw-r--r-- | arch/arm64/Kconfig | 47 |
1 files changed, 29 insertions, 18 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index ca1f93233b22..905ce1653e82 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -682,15 +682,43 @@ config ARM64_VA_BITS_47 config ARM64_VA_BITS_48 bool "48-bit" +config ARM64_USER_VA_BITS_52 + bool "52-bit (user)" + depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN) + help + Enable 52-bit virtual addressing for userspace when explicitly + requested via a hint to mmap(). The kernel will continue to + use 48-bit virtual addresses for its own mappings. + + NOTE: Enabling 52-bit virtual addressing in conjunction with + ARMv8.3 Pointer Authentication will result in the PAC being + reduced from 7 bits to 3 bits, which may have a significant + impact on its susceptibility to brute-force attacks. + + If unsure, select 48-bit virtual addressing instead. + endchoice +config ARM64_FORCE_52BIT + bool "Force 52-bit virtual addresses for userspace" + depends on ARM64_USER_VA_BITS_52 && EXPERT + help + For systems with 52-bit userspace VAs enabled, the kernel will attempt + to maintain compatibility with older software by providing 48-bit VAs + unless a hint is supplied to mmap. + + This configuration option disables the 48-bit compatibility logic, and + forces all userspace addresses to be 52-bit on HW that supports it. One + should only enable this configuration option for stress testing userspace + memory management code. If unsure say N here. + config ARM64_VA_BITS int default 36 if ARM64_VA_BITS_36 default 39 if ARM64_VA_BITS_39 default 42 if ARM64_VA_BITS_42 default 47 if ARM64_VA_BITS_47 - default 48 if ARM64_VA_BITS_48 + default 48 if ARM64_VA_BITS_48 || ARM64_USER_VA_BITS_52 choice prompt "Physical address space size" @@ -716,10 +744,6 @@ config ARM64_PA_BITS_52 endchoice -config ARM64_52BIT_VA - def_bool y - depends on ARM64_VA_BITS_48 && ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN) - config ARM64_PA_BITS int default 48 if ARM64_PA_BITS_48 @@ -1186,19 +1210,6 @@ config ARM64_CNP at runtime, and does not affect PEs that do not implement this feature. -config ARM64_FORCE_52BIT - bool "Force 52-bit virtual addresses for userspace" - depends on ARM64_52BIT_VA && EXPERT - help - For systems with 52-bit userspace VAs enabled, the kernel will attempt - to maintain compatibility with older software by providing 48-bit VAs - unless a hint is supplied to mmap. - - This configuration option disables the 48-bit compatibility logic, and - forces all userspace addresses to be 52-bit on HW that supports it. One - should only enable this configuration option for stress testing userspace - memory management code. If unsure say N here. - endmenu config ARM64_SVE |