lkml.org 
[lkml]   [2019]   [Jan]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Getting weird TPM error after rebasing my tree to security/next-general
On Thu, Jan 31, 2019 at 02:26:06PM +0200, Jarkko Sakkinen wrote:
> On Tue, Jan 29, 2019 at 03:20:16PM +0200, Jarkko Sakkinen wrote:
> > On Thu, Jan 24, 2019 at 07:43:30AM +1300, Linus Torvalds wrote:
> > > On Thu, Jan 24, 2019 at 4:36 AM Jarkko Sakkinen
> > > <jarkko.sakkinen@linux.intel.com> wrote:
> > > > >
> > > > > Is it just that this particular hardware always happened to trigger
> > > > > the ERMS case (ie "rep movsb")?
> > > >
> > > > This is the particular snippet in question:
> > > >
> > > > memcpy_fromio(buf, priv->rsp, 6);
> > > > expected = be32_to_cpup((__be32 *) &buf[2]);
> > > > if (expected > count || expected < 6)
> > > > return -EIO;
> > >
> > > Ok, strange.
> > >
> > > So what *used* to happen is that the memcpy_fromio() would just expand
> > > as a "memcpy()", and in this case, gcc would then inline the memcpy().
> > > In fact, gcc does it as a 4-byte access and a two-byte access from
> > > what I can tell.
> >
> > I verified, and it is exactly as you stated:
> >
> > 0xffffffff814aaa33 <+51>: mov (%rax),%edx
> > 0xffffffff814aaa35 <+53>: mov %edx,0x0(%rbp)
> > 0xffffffff814aaa38 <+56>: movzwl 0x4(%rax),%eax
> > 0xffffffff814aaa3c <+60>: mov %ax,0x4(%rbp)
> >
> > And your new version does exactly the same thing to the first six bytes
> > (with different opcode, but the same memory access pattern).
>
> I think I have found the root cause:
>
> memcpy_fromio(&__rsp_pa, &priv->regs_t->ctrl_rsp_pa, 8);
>
> This is from crb_map_io(). This should be read as quad word.
>
> I'll change it to ioread64() and see what happens. I don't know why it
> even has used memcpy_fromio() in the first place. I guess, when I first
> implemented the driver, I used that for no logical reason, and it has
> worked since up until now.

No, cannot be it. If you couldn't read it in two dwords, then it would
have been always broken with 32-bit build.

Anyway, just in case, I will check what address it prints out.

/Jarkko

\
 
 \ /
  Last update: 2019-01-31 17:05    [W:0.129 / U:0.292 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site