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path: root/arch/x86/include/asm/ibt.h
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2025-03-19x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in non-UAPI headersThomas Huth
While the GCC and Clang compilers already define __ASSEMBLER__ automatically when compiling assembly code, __ASSEMBLY__ is a macro that only gets defined by the Makefiles in the kernel. This can be very confusing when switching between userspace and kernelspace coding, or when dealing with UAPI headers that rather should use __ASSEMBLER__ instead. So let's standardize on the __ASSEMBLER__ macro that is provided by the compilers now. This is mostly a mechanical patch (done with a simple "sed -i" statement), with some manual tweaks in <asm/frame.h>, <asm/hw_irq.h> and <asm/setup.h> that mentioned this macro in comments with some missing underscores. Signed-off-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Juergen Gross <jgross@suse.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250314071013.1575167-38-thuth@redhat.com
2025-02-26x86/ibt: Optimize the fineibt-bhi arity 1 casePeter Zijlstra
Saves a CALL to an out-of-line thunk for the common case of 1 argument. Suggested-by: Scott Constable <scott.d.constable@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Kees Cook <kees@kernel.org> Link: https://lore.kernel.org/r/20250224124200.927885784@infradead.org
2025-02-14x86/traps: Cleanup and robustify decode_bug()Peter Zijlstra
Notably, don't attempt to decode an immediate when MOD == 3. Additionally have it return the instruction length, such that WARN like bugs can more reliably skip to the correct instruction. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Link: https://lore.kernel.org/r/20250207122546.721120726@infradead.org
2025-02-14x86/ibt: Clean up is_endbr()Peter Zijlstra
Pretty much every caller of is_endbr() actually wants to test something at an address and ends up doing get_kernel_nofault(). Fold the lot into a more convenient helper. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Link: https://lore.kernel.org/r/20250207122546.181367417@infradead.org
2023-07-10x86/alternative: Rename apply_ibt_endbr()Peter Zijlstra
The current name doesn't reflect what it does very well. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Link: https://lkml.kernel.org/r/20230622144321.427441595%40infradead.org
2023-02-09efi: x86: Wire up IBT annotation in memory attributes tableArd Biesheuvel
UEFI v2.10 extends the EFI memory attributes table with a flag that indicates whether or not all RuntimeServicesCode regions were constructed with ENDBR landing pads, permitting the OS to map these regions with IBT restrictions enabled. So let's take this into account on x86 as well. Suggested-by: Peter Zijlstra <peterz@infradead.org> # ibt_save() changes Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2022-08-19x86/ibt, objtool: Add IBT_NOSEAL()Josh Poimboeuf
Add a macro which prevents a function from getting sealed if there are no compile-time references to it. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Message-Id: <20220818213927.e44fmxkoq4yj6ybn@treble> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-03-15x86/alternative: Use .ibt_endbr_seal to seal indirect callsPeter Zijlstra
Objtool's --ibt option generates .ibt_endbr_seal which lists superfluous ENDBR instructions. That is those instructions for which the function is never indirectly called. Overwrite these ENDBR instructions with a NOP4 such that these function can never be indirect called, reducing the number of viable ENDBR targets in the kernel. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20220308154319.822545231@infradead.org
2022-03-15x86/ibt: Disable IBT around firmwarePeter Zijlstra
Assume firmware isn't IBT clean and disable it across calls. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20220308154318.759989383@infradead.org
2022-03-15x86/ibt: Base IBT bitsPeter Zijlstra
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