diff options
| author | Sami Tolvanen <samitolvanen@google.com> | 2022-04-05 15:16:18 -0700 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2022-04-13 12:16:00 -0700 |
| commit | e6f3b3c9c109ed57230996cf4a4c1b8ae7e36a81 (patch) | |
| tree | 8769c4830c2b26931ca5e5ab664cd1316bf4aab7 /arch | |
| parent | 75c1182e18f4a66bbd2c91511b6b629dac6a27dc (diff) | |
cfi: Use __builtin_function_start
Clang 14 added support for the __builtin_function_start function,
which allows us to implement the function_nocfi macro without
architecture-specific inline assembly and in a way that also works
with static initializers.
Change CONFIG_CFI_CLANG to depend on Clang >= 14, define
function_nocfi using __builtin_function_start, and remove the arm64
inline assembly implementation.
Link: https://github.com/llvm/llvm-project/commit/ec2e26eaf63558934f5b73a6e530edc453cf9508
Link: https://github.com/ClangBuiltLinux/linux/issues/1353
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will@kernel.org> # arm64
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220405221618.633743-1-samitolvanen@google.com
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/Kconfig | 5 | ||||
| -rw-r--r-- | arch/arm64/include/asm/compiler.h | 16 |
2 files changed, 1 insertions, 20 deletions
diff --git a/arch/Kconfig b/arch/Kconfig index 29b0167c088b..c1627bce4a3a 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -723,10 +723,7 @@ config ARCH_SUPPORTS_CFI_CLANG config CFI_CLANG bool "Use Clang's Control Flow Integrity (CFI)" depends on LTO_CLANG && ARCH_SUPPORTS_CFI_CLANG - # Clang >= 12: - # - https://bugs.llvm.org/show_bug.cgi?id=46258 - # - https://bugs.llvm.org/show_bug.cgi?id=47479 - depends on CLANG_VERSION >= 120000 + depends on CLANG_VERSION >= 140000 select KALLSYMS help This option enables Clang’s forward-edge Control Flow Integrity diff --git a/arch/arm64/include/asm/compiler.h b/arch/arm64/include/asm/compiler.h index dc3ea4080e2e..6fb2e6bcc392 100644 --- a/arch/arm64/include/asm/compiler.h +++ b/arch/arm64/include/asm/compiler.h @@ -23,20 +23,4 @@ #define __builtin_return_address(val) \ (void *)(ptrauth_clear_pac((unsigned long)__builtin_return_address(val))) -#ifdef CONFIG_CFI_CLANG -/* - * With CONFIG_CFI_CLANG, the compiler replaces function address - * references with the address of the function's CFI jump table - * entry. The function_nocfi macro always returns the address of the - * actual function instead. - */ -#define function_nocfi(x) ({ \ - void *addr; \ - asm("adrp %0, " __stringify(x) "\n\t" \ - "add %0, %0, :lo12:" __stringify(x) \ - : "=r" (addr)); \ - addr; \ -}) -#endif - #endif /* __ASM_COMPILER_H */ |