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| author | Peter Zijlstra <peterz@infradead.org> | 2022-03-08 16:30:17 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-03-15 10:32:33 +0100 |
| commit | 156ff4a544ae13c5fd6759a09ecb069f7059c1a1 (patch) | |
| tree | 4e429b976672a1634463f7792a84604a80a63d82 /arch/x86/Kconfig | |
| parent | objtool: Have WARN_FUNC fall back to sym+off (diff) | |
| download | linux-156ff4a544ae13c5fd6759a09ecb069f7059c1a1.tar.xz linux-156ff4a544ae13c5fd6759a09ecb069f7059c1a1.zip | |
x86/ibt: Base IBT bits
Add Kconfig, Makefile and basic instruction support for x86 IBT.
(Ab)use __DISABLE_EXPORTS to disable IBT since it's already employed
to mark compressed and purgatory. Additionally mark realmode with it
as well to avoid inserting ENDBR instructions there. While ENDBR is
technically a NOP, inserting them was causing some grief due to code
growth. There's also a problem with using __noendbr in code compiled
without -fcf-protection=branch.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154317.519875203@infradead.org
Diffstat (limited to 'arch/x86/Kconfig')
| -rw-r--r-- | arch/x86/Kconfig | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 9f5bd41bf660..19d16c054a96 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1861,6 +1861,26 @@ config X86_UMIP specific cases in protected and virtual-8086 modes. Emulated results are dummy. +config CC_HAS_IBT + # GCC >= 9 and binutils >= 2.29 + # Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654 + # Clang/LLVM >= 14 + # fentry check to work around https://reviews.llvm.org/D111108 + def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \ + (CC_IS_CLANG && $(success,echo "void a(void) {}" | $(CC) -Werror $(CLANG_FLAGS) -fcf-protection=branch -mfentry -pg -x c - -c -o /dev/null))) && \ + $(as-instr,endbr64) + +config X86_KERNEL_IBT + prompt "Indirect Branch Tracking" + bool + depends on X86_64 && CC_HAS_IBT + help + Build the kernel with support for Indirect Branch Tracking, a + hardware support course-grain forward-edge Control Flow Integrity + protection. It enforces that all indirect calls must land on + an ENDBR instruction, as such, the compiler will instrument the + code with them to make this happen. + config X86_INTEL_MEMORY_PROTECTION_KEYS prompt "Memory Protection Keys" def_bool y |