diff options
| author | Sami Tolvanen | 2022-04-05 15:16:18 -0700 |
|---|---|---|
| committer | Kees Cook | 2022-04-13 12:16:00 -0700 |
| commit | e6f3b3c9c109ed57230996cf4a4c1b8ae7e36a81 (patch) | |
| tree | 8769c4830c2b26931ca5e5ab664cd1316bf4aab7 /include | |
| 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 'include')
| -rw-r--r-- | include/linux/compiler-clang.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h index babb1347148c..c84fec767445 100644 --- a/include/linux/compiler-clang.h +++ b/include/linux/compiler-clang.h @@ -69,6 +69,16 @@ #define __nocfi __attribute__((__no_sanitize__("cfi"))) #define __cficanonical __attribute__((__cfi_canonical_jump_table__)) +#if defined(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) __builtin_function_start(x) +#endif + /* * Turn individual warnings and errors on and off locally, depending * on version. |