Re: [v3 PATCH 00/10] x86: Enable User-Mode Instruction Prevention

From: H. Peter Anvin
Date: Wed Jan 25 2017 - 15:47:36 EST

On 01/25/17 12:23, Ricardo Neri wrote:
> * SMSW returns the value with which the CR0 register is programmed in
> head_32/64.S at boot time. This is, the following bits are enabed:
> CR0.0 for Protection Enable, CR.1 for Monitor Coprocessor, CR.4 for
> Extension Type, which will always be 1 in recent processors with UMIP;
> CR.5 for Numeric Error, CR0.16 for Write Protect, CR0.18 for Alignment
> Mask. Additionally, in x86_64, CR0.31 for Paging is set.

SMSW only returns CR0[15:0], so the reference here to CR0[31:16] seems odd.