Messages in this thread | | | From | Denys Vlasenko <> | Date | Sat, 28 Mar 2015 12:01:34 +0100 | Subject | Re: ia32_sysenter_target does not preserve EFLAGS |
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On Sat, Mar 28, 2015 at 1:39 AM, Linus Torvalds <torvalds@linux-foundation.org> wrote: > What part of "don't leak kernel data" did you have trouble understanding? > > IOW, this is a *security* issue. Stop arguing for crazy shit.
We can zero the registers instead of saving/restoring them. push/pop pair takes 1-2 cycles at best, whereas on four-issue CPUs "xor reg,reg" has throughput of four instructions at a time, often even not requiring an execution unit.
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