The HAVE_CFI_ICALL_NORMALIZE_INTEGERS option has some tricky conditions when KASAN or GCOV are turned on, as in that case we need some clang and rustc fixes [1][2] to avoid boot failures. The intent with the current setup is that you should be able to override the check and turn on the option if your clang/rustc has the fix. However, this override does not work in practice. Thus, use the new RUSTC_LLVM_VERSION to correctly implement the check for whether the fix is available. Additionally, remove KASAN_HW_TAGS from the list of incompatible options. The CFI_ICALL_NORMALIZE_INTEGERS option is incompatible with KASAN because LLVM will emit some constructors when using KASAN that are assigned incorrect CFI tags. These constructors are emitted due to use of -fsanitize=kernel-address or -fsanitize=kernel-hwaddress that are respectively passed when KASAN_GENERIC or KASAN_SW_TAGS are enabled. However, the KASAN_HW_TAGS option relies on hardware support for MTE instead and does not pass either flag. (Note also that KASAN_HW_TAGS does not `select CONSTRUCTORS`.) Link: https://github.com/llvm/llvm-project/pull/104826 [1] Link: https://github.com/rust-lang/rust/pull/129373 [2] Fixes: 4c66f8307ac0 ("cfi: encode cfi normalized integers + kasan/gcov bug in Kconfig") Signed-off-by: Alice Ryhl <aliceryhl@xxxxxxxxxx> --- arch/Kconfig | 26 ++++++++++++-------------- init/Kconfig | 2 +- 2 files changed, 13 insertions(+), 15 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index 8af374ea1adc..00163e4a237c 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -838,7 +838,7 @@ config CFI_CLANG config CFI_ICALL_NORMALIZE_INTEGERS bool "Normalize CFI tags for integers" depends on CFI_CLANG - depends on HAVE_CFI_ICALL_NORMALIZE_INTEGERS + depends on HAVE_CFI_ICALL_NORMALIZE_INTEGERS_CLANG help This option normalizes the CFI tags for integer types so that all integer types of the same size and signedness receive the same CFI @@ -851,21 +851,19 @@ config CFI_ICALL_NORMALIZE_INTEGERS This option is necessary for using CFI with Rust. If unsure, say N. -config HAVE_CFI_ICALL_NORMALIZE_INTEGERS - def_bool !GCOV_KERNEL && !KASAN - depends on CFI_CLANG +config HAVE_CFI_ICALL_NORMALIZE_INTEGERS_CLANG + def_bool y depends on $(cc-option,-fsanitize=kcfi -fsanitize-cfi-icall-experimental-normalize-integers) - help - Is CFI_ICALL_NORMALIZE_INTEGERS supported with the set of compilers - currently in use? + # With GCOV/KASAN we need this fix: https://github.com/llvm/llvm-project/pull/104826 + depends on CLANG_VERSION >= 190000 || (!GCOV_KERNEL && !KASAN_GENERIC && !KASAN_SW_TAGS) - This option defaults to false if GCOV or KASAN is enabled, as there is - an LLVM bug that makes normalized integers tags incompatible with - KASAN and GCOV. Kconfig currently does not have the infrastructure to - detect whether your rustc compiler contains the fix for this bug, so - it is assumed that it doesn't. If your compiler has the fix, you can - explicitly enable this option in your config file. The Kconfig logic - needed to detect this will be added in a future kernel release. +config HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC + def_bool y + depends on HAVE_CFI_ICALL_NORMALIZE_INTEGERS_CLANG + depends on RUSTC_VERSION >= 107900 + # With GCOV/KASAN we need this fix: https://github.com/rust-lang/rust/pull/129373 + depends on (RUSTC_LLVM_VERSION >= 190000 && RUSTC_VERSION >= 108200) || \ + (!GCOV_KERNEL && !KASAN_GENERIC && !KASAN_SW_TAGS) config CFI_PERMISSIVE bool "Use CFI in permissive mode" diff --git a/init/Kconfig b/init/Kconfig index 98cf859d58c2..c521e1421ad4 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1950,7 +1950,7 @@ config RUST depends on !GCC_PLUGIN_RANDSTRUCT depends on !RANDSTRUCT depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE - depends on !CFI_CLANG || RUSTC_VERSION >= 107900 && HAVE_CFI_ICALL_NORMALIZE_INTEGERS + depends on !CFI_CLANG || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC select CFI_ICALL_NORMALIZE_INTEGERS if CFI_CLANG depends on !CALL_PADDING || RUSTC_VERSION >= 108100 depends on !KASAN_SW_TAGS -- 2.47.0.rc0.187.ge670bccf7e-goog
