x86/alternatives: Remove faulty optimization
commit 4ba89dd6 upstream. The following commit 095b8303 ("x86/alternative: Make custom return thunk unconditional") made '__x86_return_thunk' a placeholder value. All code setting X86_FEATURE_RETHUNK also changes the value of 'x86_return_thunk'. So the optimization at the beginning of apply_returns() is dead code. Also, before the above-mentioned commit, the optimization actually had a bug It bypassed __static_call_fixup(), causing some raw returns to remain unpatched in static call trampolines. Thus the 'Fixes' tag. Fixes: d2408e04 ("x86/alternative: Optimize returns patching") Signed-off-by:Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by:
Ingo Molnar <mingo@kernel.org> Signed-off-by:
Borislav Petkov (AMD) <bp@alien8.de> Acked-by:
Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/16d19d2249d4485d8380fb215ffaae81e6b8119e.1693889988.git.jpoimboe@kernel.org Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
parent
4b0ccd81
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