Re: [PATCH 01/17] x86, fpu: wrap get_xsave_addr() to make it safer

Dave Hansen
2015-03-24T23:42:23Z

On 03/24/2015 03:28 PM, Andy Lutomirski wrote:
> Your function appears to be getting it for write (I assume that's what
> the unlazy_fpu is for), so I'd rather have it called
> tsk_get_xsave_field_for_write or something like that.

It should be entirely read-only.

For MPX (the only user of get_xsave_addr() iirc), we are only worried
about getting the status codes (and addresses) out of the bndstatus
register and making sure that the kernel-recorded bounds directory
address matches the bndcfgu (configuration) register.

We don't ever write to the registers.