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Groups > linux.kernel > #1244957
| From | Denys Vlasenko <dvlasenk@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v2 07/36] x86/entry/64/compat: After SYSENTER, move STI after the NT fixup |
| Date | 2015-10-12 19:50 +0200 |
| Message-ID | <qiPou-64e-23@gated-at.bofh.it> (permalink) |
| References | <qgoC6-715-5@gated-at.bofh.it> <qgoC6-715-9@gated-at.bofh.it> <qh0R3-3eS-1@gated-at.bofh.it> <qhLPY-3oh-9@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
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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[PATCH v2 07/36] x86/entry/64/compat: After SYSENTER, move STI after the NT fixup Andy Lutomirski <luto@kernel.org> - 2015-10-06 02:50 +0200
[tip:x86/asm] x86/entry/64/compat: After SYSENTER, move STI after the NT fixup tip-bot for Andy Lutomirski <tipbot@zytor.com> - 2015-10-07 18:20 +0200
Re: [PATCH v2 07/36] x86/entry/64/compat: After SYSENTER, move STI after the NT fixup Denys Vlasenko <dvlasenk@redhat.com> - 2015-10-07 19:40 +0200
Re: [PATCH v2 07/36] x86/entry/64/compat: After SYSENTER, move STI after the NT fixup Andy Lutomirski <luto@amacapital.net> - 2015-10-07 21:10 +0200
Re: [PATCH v2 07/36] x86/entry/64/compat: After SYSENTER, move STI after the NT fixup Andy Lutomirski <luto@amacapital.net> - 2015-10-09 21:50 +0200
Re: [PATCH v2 07/36] x86/entry/64/compat: After SYSENTER, move STI after the NT fixup Denys Vlasenko <dvlasenk@redhat.com> - 2015-10-12 19:50 +0200
Re: [PATCH v2 07/36] x86/entry/64/compat: After SYSENTER, move STI after the NT fixup Brian Gerst <brgerst@gmail.com> - 2015-10-12 20:20 +0200
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