On Thu, Jul 23, 2015 at 11:33 AM, Andy Lutomirski <l...@amacapital.net> wrote: > On Thu, Jul 23, 2015 at 11:01 AM, Andy Lutomirski <l...@amacapital.net> wrote: >> On Thu, Jul 23, 2015 at 10:27 AM, Brian Gerst <brge...@gmail.com> wrote: >>> On Thu, Jul 23, 2015 at 12:02 PM, Andy Lutomirski <l...@amacapital.net> >>> wrote: >>>> On Thu, Jul 23, 2015 at 8:56 AM, Steven Rostedt <rost...@goodmis.org> >>>> wrote: >>>>> On Thu, 23 Jul 2015 08:31:39 -0700 >>>>> Andy Lutomirski <l...@kernel.org> wrote: >>>>> >>>>>> Switch from wrmsr to wrmsrl_safe to prepare to merge the 32-bit and >>>>>> 64-bit code, and use __KERNEL_CS explicitly to initialize >>>>>> MSR_IA32_SYSENTER_CS. While we're at it, tweak the whitespace a >>>>>> bit. >>>>> >>>>> Saying "prepare to merge the 32-bit and 64-bit" isn't that informative >>>>> to why this patch is needed. Can you please describe in the change log >>>>> what can fault with the wrmsr call, when we do the merge? >>>> >>>> Oh... >>>> >>>> Nothing can fault in the wrmsr as far as I know, but maybe there's a >>>> CPU out there that advertises SEP but doesn't have the MSRs. >>>> >>>> Ingo, Thomas, want a v2 that explains that the wrmsr_safe is there for >>>> consistency but that I don't know why 32bit does it? Another option >>>> would be to remove the _safe from the 32-bit version. >>> >>> There is an erratum with SEP being advertised but not available on >>> early P6 models, but we already check for that in the cpu setup code. >>> There shouldn't be a problem with a fault. >> >> I can make a v2 that gets rid of the _safe. >> > > Ugh. wrmsrl_safe is a function but wrmsrl isn't. I'll fix that and send a > v2. > > Gah, macros.
On third thought, no v2. It's *64-bit* CPUs that might want the _safe. We aren't currently checking SEP. Maybe there's a non-SEP AMD CPU and we never noticed because SEP was never useful on AMD 64-bit CPUs. I'll send a followup. > > --Andy -- Andy Lutomirski AMA Capital Management, LLC -- 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/
