Messages in this thread | | | Date | Thu, 18 Aug 2022 10:00:59 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH] x86/build: Move '-mindirect-branch-cs-prefix' out of GCC-only block |
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On Thu, Aug 18, 2022 at 09:45:39AM +0200, Peter Zijlstra wrote:
> The thing to do is boot with (warning, *very* verbose): > > "spectre_v2=retpoline,lfence debug-alternative" > > and observe that the retpoline sites all replace: > > "cs call __x86_indirect_thunk_r11" (6 bytes) > > with: > > "lfence; jmp *%r11" (6 bytes)
^^ call, ofc, unless the original was jmp then jmp...
/me goes get more morning juice in an attempt to wake up.
> > > This being clang, you'll ofcourse still have a few weird: > > "Jcc.d32 __x86_indirect_thunk_r11" > > sites that will not be able to be replaced, but there's nothing I can do > about that other than to continue to encourage y'all to stop emitting > them ;-)
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