[lkml]   [2019]   [Mar]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC][PATCH] tracing/x86: Save CR2 before tracing irqsoff on error_entry
On Thu, Mar 21, 2019 at 11:27 AM Peter Zijlstra <> wrote:
> On Thu, Mar 21, 2019 at 11:05:06AM -0700, Andy Lutomirski wrote:
> > Ugh.
> >
> > I certainly agree in principle that sticking the CR2 read into the asm
> > is the right solution. But this patch makes the spaghetti even more
> > tangled. Maybe we can rearrange the code a bit so that the entry
> > sequence saves at least one register before calling error_entry, so we
> > can do it the obvious way.
> What is the obvious way? Note that with all the Xen/paravirt-me-harder
> bits on, we need to clobber at least RAX to get CR2.
> And most of the patch was munging the paravirt bits to make that happen.
> Another thing I did notices is that CLAC and CLD are not next to one
> another in these paths.

The thing I really don't like is all the EBX crud to try to get
everything in to the right order.

 \ /
  Last update: 2019-03-21 19:29    [W:0.085 / U:3.992 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site