Messages in this thread | | | Date | Tue, 20 May 2008 10:59:41 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [RFC] x86: xsave/xrstor support, ucontext_t extensions |
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Suresh Siddha wrote: > > This issue of not-zeroing, is present in only 64bit kernels and for 64bit apps, > right? > > 64bit app signal handling uses only rt_frame, so we can add an uc_flag for > them and for 32bit apps, kernel was always zero'ing the reserved bits > at the end of _fpstate. > > In short, for non-rt frames, they can check the reserved bits at the end > of fpstate frame and for rt-frames (perhaps even for 32bit rt frame handling) > apps can check for uc_flag aswell, for extended state presence. Is this > good enough? >
Are we sure about the "always" bit here (I suspect yes, but we may want to double-check at least back to 2.2 or 2.4.)
Anyway, seems reasonable enough to me.
-hpa
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