3 Commits

Author	SHA1	Message	Date
Scott Constable	5b519cf1fc	[X86] Add Indirect Thunk Support to X86 to mitigate Load Value Injection (LVI) ... This pass replaces each indirect call/jump with a direct call to a thunk that looks like: lfence jmpq *%r11 This ensures that if the value in register %r11 was loaded from memory, then the value in %r11 is (architecturally) correct prior to the jump. Also adds a new target feature to X86: +lvi-cfi ("cfi" meaning control-flow integrity) The feature can be added via clang CLI using -mlvi-cfi. This is an alternate implementation to https://reviews.llvm.org/D75934 That merges the thunk insertion functionality with the existing X86 retpoline code. Differential Revision: https://reviews.llvm.org/D76812	2020-04-03 00:34:39 -07:00
Scott Constable	b1d581019f	[X86] Refactor X86IndirectThunks.cpp to Accommodate Mitigations other than Retpoline ... Introduce a ThunkInserter CRTP base class from which new thunk types can inherit, e.g., thunks to mitigate https://software.intel.com/security-software-guidance/software-guidance/load-value-injection. Differential Revision: https://reviews.llvm.org/D76811	2020-04-02 22:09:54 -07:00
Scott Constable	71e8021d82	[X86][NFC] Generalize the naming of "Retpoline Thunks" and related code to "Indirect Thunks" ... There are applications for indirect call/branch thunks other than retpoline for Spectre v2, e.g., https://software.intel.com/security-software-guidance/software-guidance/load-value-injection Therefore it makes sense to refactor X86RetpolineThunks as a more general capability. Differential Revision: https://reviews.llvm.org/D76810	2020-04-02 21:55:13 -07:00