[PATCH v2 0/7] Tracing vs CR2 (and cleanups)

[Peter Zijlstra]

Hi,

Eiichi-san re-discovered the bug earlier found by He Zhe which we've failed to
fix due to getting distracted by discussing how to untangle entry_64.S.

These 3 patches are basically a completion of the initial approach I suggested
in that earlier thread:

  https://lkml.kernel.org/r/20190320221534.165ab87b@xxxxxxxxxxxxxxxx

Since v1:

 - idtentry_part 'cleanup'
 - extra sanity check and comment
 - read_cr2=1 for do_double_fault
 - #BP vs IST cleanup
 - IDTENTRYx() C wrapper

The thing boots on x86_64 with lockdep on, survives function-trace,
selftests/x86 and perf-test.