diff options
Diffstat (limited to 'arch/Kconfig')
| -rw-r--r-- | arch/Kconfig | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/arch/Kconfig b/arch/Kconfig index 77b3e21c4844..b27eac589618 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -611,6 +611,133 @@ config LD_DEAD_CODE_DATA_ELIMINATION sections (e.g., '.text.init'). Typically '.' in section names is used to distinguish them from label names / C identifiers. +config LTO + def_bool n + +config ARCH_SUPPORTS_LTO_CLANG + bool + help + An architecture should select this option it supports: + - compiling with clang, + - compiling inline assembly with clang's integrated assembler, + - and linking with either lld or GNU gold w/ LLVMgold. + +config ARCH_SUPPORTS_THINLTO + bool + help + An architecture should select this if it supports clang's ThinLTO. + +config THINLTO + bool "Use clang ThinLTO (EXPERIMENTAL)" + depends on LTO_CLANG && ARCH_SUPPORTS_THINLTO + default y + help + Use ThinLTO to speed up Link Time Optimization. + +choice + prompt "Link-Time Optimization (LTO) (EXPERIMENTAL)" + default LTO_NONE + help + This option turns on Link-Time Optimization (LTO). + +config LTO_NONE + bool "None" + +config LTO_CLANG + bool "Use clang Link Time Optimization (LTO) (EXPERIMENTAL)" + depends on ARCH_SUPPORTS_LTO_CLANG + depends on !FTRACE_MCOUNT_RECORD || HAVE_C_RECORDMCOUNT + depends on !KASAN + select LTO + select THIN_ARCHIVES + select LD_DEAD_CODE_DATA_ELIMINATION + help + This option enables clang's Link Time Optimization (LTO), which allows + the compiler to optimize the kernel globally at link time. If you + enable this option, the compiler generates LLVM IR instead of object + files, and the actual compilation from IR occurs at the LTO link step, + which may take several minutes. + + If you select this option, you must compile the kernel with clang >= + 5.0 (make CC=clang) and GNU gold from binutils >= 2.27, and have the + LLVMgold plug-in in LD_LIBRARY_PATH. + +endchoice + +config CFI + bool + +config CFI_PERMISSIVE + bool "Use CFI in permissive mode" + depends on CFI + help + When selected, Control Flow Integrity (CFI) violations result in a + warning instead of a kernel panic. This option is useful for finding + CFI violations in drivers during development. + +config CFI_CLANG + bool "Use clang Control Flow Integrity (CFI) (EXPERIMENTAL)" + depends on LTO_CLANG + depends on KALLSYMS + select CFI + help + This option enables clang Control Flow Integrity (CFI), which adds + runtime checking for indirect function calls. + +config CFI_CLANG_SHADOW + bool "Use CFI shadow to speed up cross-module checks" + default y + depends on CFI_CLANG + help + If you select this option, the kernel builds a fast look-up table of + CFI check functions in loaded modules to reduce overhead. + +config ARCH_SUPPORTS_SHADOW_CALL_STACK + bool + help + An architecture should select this if it supports Clang's Shadow + Call Stack, has asm/scs.h, and implements runtime support for shadow + stack switching. + +choice + prompt "Return-oriented programming (ROP) protection" + default ROP_PROTECTION_NONE + help + This option controls kernel protections against return-oriented + programming (ROP) attacks, which involve overwriting function return + addresses. + +config ROP_PROTECTION_NONE + bool "None" + +config SHADOW_CALL_STACK + bool "Clang Shadow Call Stack" + depends on ARCH_SUPPORTS_SHADOW_CALL_STACK + help + This option enables Clang's Shadow Call Stack, which uses a + shadow stack to protect function return addresses from being + overwritten by an attacker. More information can be found from + Clang's documentation: + + https://clang.llvm.org/docs/ShadowCallStack.html + + Note that security guarantees in the kernel differ from the ones + documented for user space. The kernel must store addresses of shadow + stacks used by other tasks and interrupt handlers in memory, which + means an attacker capable reading and writing arbitrary memory may + be able to locate them and hijack control flow by modifying shadow + stacks that are not currently in use. + +endchoice + +config SHADOW_CALL_STACK_VMAP + bool "Use virtually mapped shadow call stacks" + depends on SHADOW_CALL_STACK + help + Use virtually mapped shadow call stacks. Selecting this option + provides better stack exhaustion protection, but increases per-thread + memory consumption as a full page is allocated for each shadow stack. + config HAVE_ARCH_WITHIN_STACK_FRAMES bool help @@ -973,4 +1100,18 @@ config HAVE_ARCH_COMPILER_H linux/compiler-*.h in order to override macro definitions that those headers generally provide. +# Select if the architecture has support for applying RELR relocations. +config ARCH_HAS_RELR + bool + +config RELR + bool "Use RELR relocation packing" + depends on ARCH_HAS_RELR && TOOLS_SUPPORT_RELR + default y + help + Store the kernel's dynamic relocations in the RELR relocation packing + format. Requires a compatible linker (LLD supports this feature), as + well as compatible NM and OBJCOPY utilities (llvm-nm and llvm-objcopy + are compatible). + source "kernel/gcov/Kconfig" |