[PATCH] D75935: Add RET-hardening Support to X86 to mitigate Load Value Injection (LVI)

[Scott Constable via Phabricator via llvm-commits]

sconstab created this revision.
sconstab added reviewers: craig.topper, andrew.w.kaylor, chandlerc, zbrid.
Herald added subscribers: jfb, hiraditya, mgorny.
Herald added a project: LLVM.

Adding a pass that replaces every `ret` instruction with the sequence:

  pop <scratch-reg>
  lfence
  jmp *<scratch-reg>

where `<scratch-reg>` is some available scratch register, according to the
calling convention of the function being mitigated.


https://reviews.llvm.org/D75935

Files:
  llvm/lib/Target/X86/CMakeLists.txt
  llvm/lib/Target/X86/X86.h
  llvm/lib/Target/X86/X86LoadValueInjectionRetHardening.cpp
  llvm/lib/Target/X86/X86TargetMachine.cpp
  llvm/test/CodeGen/X86/O0-pipeline.ll
  llvm/test/CodeGen/X86/O3-pipeline.ll
  llvm/test/CodeGen/X86/lvi-hardening-ret.ll

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