Messages in this thread | | | Date | Mon, 12 Oct 2015 19:48:02 +0200 | From | Denys Vlasenko <> | Subject | Re: [PATCH v2 07/36] x86/entry/64/compat: After SYSENTER, move STI after the NT fixup |
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On 10/09/2015 09:48 PM, Andy Lutomirski wrote: > Anyway, it's still a win, but I'll keep playing. There may be even > better ways to do this.
Such as this? Drop OR, check for cleared IF here:
testl $X86_EFLAGS_NT, EFLAGS(%rsp) jnz sysenter_fix_flags testl $X86_EFLAGS_IF, EFLAGS(%rsp) jz sysenter_fix_flags sysenter_flags_fixed:
and make sysenter_fix_flags code set IF in addition to TF clearing. This way, we don't even have an unconditional RMW op.
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