x86/mm: Fix bogus warning during EFI bootup, use boot_cpu_has() instead of this_cpu_has() in build_cr3_noflush()

Linus reported the following boot warning:

  WARNING: CPU: 0 PID: 0 at arch/x86/include/asm/tlbflush.h:134 load_new_mm_cr3+0x114/0x170
  [...]
  Call Trace:
  switch_mm_irqs_off+0x267/0x590
  switch_mm+0xe/0x20
  efi_switch_mm+0x3e/0x50
  efi_enter_virtual_mode+0x43f/0x4da
  start_kernel+0x3bf/0x458
  secondary_startup_64+0xa5/0xb0

... after merging:

  03781e40890c: x86/efi: Use efi_switch_mm() rather than manually twiddling with %cr3

When the platform supports PCID and if CONFIG_DEBUG_VM=y is enabled,
build_cr3_noflush() (called via switch_mm()) does a sanity check to see
if X86_FEATURE_PCID is set.

Presently, build_cr3_noflush() uses "this_cpu_has(X86_FEATURE_PCID)" to
perform the check but this_cpu_has() works only after SMP is initialized
(i.e. per cpu cpu_info's should be populated) and this happens to be very
late in the boot process (during rest_init()).

As efi_runtime_services() are called during (early) kernel boot time
and run time, modify build_cr3_noflush() to use boot_cpu_has() all the
time. As suggested by Dave Hansen, this should be OK because all CPU's have
same capabilities on x86.

With this change the warning is fixed.

( Dave also suggested that we put a warning in this_cpu_has() if it's used
  early in the boot process. This is still work in progress as it affects
  MCE. )

Reported-by: Linus Torvalds <[email protected]>
Signed-off-by: Sai Praneeth Prakhya <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Lee Chun-Yi <[email protected]>
Cc: Matt Fleming <[email protected]>
Cc: Michael S. Tsirkin <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ravi Shankar <[email protected]>
Cc: Ricardo Neri <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions