diff options
Diffstat (limited to 'arch/x86/Kconfig')
| -rw-r--r-- | arch/x86/Kconfig | 68 |
1 files changed, 50 insertions, 18 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index d9a94da0c29f..2fa55851d2a9 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -22,6 +22,7 @@ config X86 select ANON_INODES select ARCH_CLOCKSOURCE_DATA select ARCH_DISCARD_MEMBLOCK + select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS select ARCH_HAS_DEVMEM_IS_ALLOWED @@ -49,7 +50,6 @@ config X86 select ARCH_WANTS_DYNAMIC_TASK_STRUCT select ARCH_WANT_FRAME_POINTERS select ARCH_WANT_IPC_PARSE_VERSION if X86_32 - select ARCH_WANT_OPTIONAL_GPIOLIB select BUILDTIME_EXTABLE_SORT select CLKEVT_I8253 select CLKSRC_I8253 if X86_32 @@ -294,11 +294,6 @@ config X86_32_LAZY_GS def_bool y depends on X86_32 && !CC_STACKPROTECTOR -config ARCH_HWEIGHT_CFLAGS - string - default "-fcall-saved-ecx -fcall-saved-edx" if X86_32 - default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64 - config ARCH_SUPPORTS_UPROBES def_bool y @@ -643,7 +638,7 @@ config STA2X11 select X86_DMA_REMAP select SWIOTLB select MFD_STA2X11 - select ARCH_REQUIRE_GPIOLIB + select GPIOLIB default n ---help--- This adds support for boards based on the STA2X11 IO-Hub, @@ -1934,21 +1929,26 @@ config RANDOMIZE_BASE attempts relying on knowledge of the location of kernel code internals. - The kernel physical and virtual address can be randomized - from 16MB up to 1GB on 64-bit and 512MB on 32-bit. (Note that - using RANDOMIZE_BASE reduces the memory space available to - kernel modules from 1.5GB to 1GB.) + On 64-bit, the kernel physical and virtual addresses are + randomized separately. The physical address will be anywhere + between 16MB and the top of physical memory (up to 64TB). The + virtual address will be randomized from 16MB up to 1GB (9 bits + of entropy). Note that this also reduces the memory space + available to kernel modules from 1.5GB to 1GB. + + On 32-bit, the kernel physical and virtual addresses are + randomized together. They will be randomized from 16MB up to + 512MB (8 bits of entropy). Entropy is generated using the RDRAND instruction if it is supported. If RDTSC is supported, its value is mixed into the entropy pool as well. If neither RDRAND nor RDTSC are - supported, then entropy is read from the i8254 timer. - - Since the kernel is built using 2GB addressing, and - PHYSICAL_ALIGN must be at a minimum of 2MB, only 10 bits of - entropy is theoretically possible. Currently, with the - default value for PHYSICAL_ALIGN and due to page table - layouts, 64-bit uses 9 bits of entropy and 32-bit uses 8 bits. + supported, then entropy is read from the i8254 timer. The + usable entropy is limited by the kernel being built using + 2GB addressing, and that PHYSICAL_ALIGN must be at a + minimum of 2MB. As a result, only 10 bits of entropy are + theoretically possible, but the implementations are further + limited due to memory layouts. If CONFIG_HIBERNATE is also enabled, KASLR is disabled at boot time. To enable it, boot with "kaslr" on the kernel command @@ -1988,6 +1988,38 @@ config PHYSICAL_ALIGN Don't change this unless you know what you are doing. +config RANDOMIZE_MEMORY + bool "Randomize the kernel memory sections" + depends on X86_64 + depends on RANDOMIZE_BASE + default RANDOMIZE_BASE + ---help--- + Randomizes the base virtual address of kernel memory sections + (physical memory mapping, vmalloc & vmemmap). This security feature + makes exploits relying on predictable memory locations less reliable. + + The order of allocations remains unchanged. Entropy is generated in + the same way as RANDOMIZE_BASE. Current implementation in the optimal + configuration have in average 30,000 different possible virtual + addresses for each memory section. + + If unsure, say N. + +config RANDOMIZE_MEMORY_PHYSICAL_PADDING + hex "Physical memory mapping padding" if EXPERT + depends on RANDOMIZE_MEMORY + default "0xa" if MEMORY_HOTPLUG + default "0x0" + range 0x1 0x40 if MEMORY_HOTPLUG + range 0x0 0x40 + ---help--- + Define the padding in terabytes added to the existing physical + memory size during kernel memory randomization. It is useful + for memory hotplug support but reduces the entropy available for + address randomization. + + If unsure, leave at the default value. + config HOTPLUG_CPU bool "Support for hot-pluggable CPUs" depends on SMP |