> From: Dave Hansen [mailto:dave.han...@linux.intel.com] > Sent: Tuesday, May 05, 2015 12:52 PM > To: Ingo Molnar; linux-kernel@vger.kernel.org > Cc: Andy Lutomirski; Borislav Petkov; Yu, Fenghua; H. Peter Anvin; Linus > Torvalds; Oleg Nesterov; Thomas Gleixner > Subject: Re: [PATCH 198/208] x86/fpu: Document the various fpregs state > formats > > On 05/05/2015 10:58 AM, Ingo Molnar wrote: > > +/* > > + * This is our most modern FPU state format, as saved by the XSAVE > > + * and restored by the XRSTOR instructions. > > + * > > + * It consists of a legacy fxregs portion, an xstate header and > > + * subsequent fixed size areas as defined by the xstate header. > > + * Not all CPUs support all the extensions. > > + */ > > struct xregs_state { > > struct fxregs_state i387; > > struct xstate_header header; > > @@ -150,6 +169,13 @@ struct xregs_state { > > /* New processor state extensions will go here. */ } __attribute__ > > ((packed, aligned (64))); > > Fenghua has a "fix" for this, but I think this misses a pretty big point.
Here is the "fix" patch Dave referred to: https://lkml.org/lkml/2015/4/22/9 > > This structure includes only the "legacy" state, followed by the header. > The remainder of the layout here is enumerated in CPUID leaves and can not > be laid out in a structure because we do not know what it looks like until we > run CPUID. > > There is logically a variable length array at the end of this sucker. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
