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Diffstat (limited to 'llvm/docs')
-rw-r--r-- | llvm/docs/LangRef.rst | 22 |
1 files changed, 13 insertions, 9 deletions
diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst index fa85b6e6ee7..7ec157fb73c 100644 --- a/llvm/docs/LangRef.rst +++ b/llvm/docs/LangRef.rst @@ -1643,15 +1643,19 @@ example: ``speculative_load_hardening`` This attribute indicates that `Speculative Load Hardening <https://llvm.org/docs/SpeculativeLoadHardening.html>`_ - should be enabled for the function body. - - Speculative Load Hardening is a best-effort mitigation against - information leak attacks that make use of control flow - miss-speculation - specifically miss-speculation of whether a branch - is taken or not. Typically vulnerabilities enabling such attacks are - classified as "Spectre variant #1". Notably, this does not attempt to - mitigate against miss-speculation of branch target, classified as - "Spectre variant #2" vulnerabilities. + should be enabled for the function body. This is a best-effort attempt to + mitigate all known speculative execution information leak vulnerabilities + that are based on the fundamental principles of modern processors' + speculative execution. These vulnerabilities are classified as "Spectre + variant #1" vulnerabilities typically. Notably, this does not attempt to + mitigate any vulnerabilities where the speculative execution and/or + prediction devices of specific processors can be *completely* undermined + (such as "Branch Target Injection", a.k.a, "Spectre variant #2"). Instead, + this is a target-independent request to harden against the completely + generic risk posed by speculative execution to incorrectly load secret data, + making it available to some micro-architectural side-channel for information + leak. For a processor without any speculative execution or predictors, this + is expected to be a no-op. When inlining, the attribute is sticky. Inlining a function that carries this attribute will cause the caller to gain the attribute. This is intended |