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[v10,0/4] SRF: Fix offline CPU preventing pc6 entry

Message ID 20250205152057.171030-1-artem.bityutskiy@linux.intel.com
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Series SRF: Fix offline CPU preventing pc6 entry | expand

Message

Artem Bityutskiy Feb. 5, 2025, 3:20 p.m. UTC 
Code for determining the mwait hint for the deepest C-state by
inspecting CPUID leaf 0x5 in mwait_play_dead() assumes that, if the
number of sub-states for a given major C-state is nonzero, those
sub-states are always represented by consecutive numbers starting from
0. This assumption is not based on the documented platform behavior and
in fact it is not met on recent Intel platforms.

Changes since v9:
  * Patch 3/4: remove the '__cpuidle' instrumentation tag from
    intel_idle_enter_dead() to address this objtool warning: call to
    cpuidle_get_cpu_driver() leaves .noinstr.text section.
  * Patch 1/4: rename 'hint' to 'eax_hint' in the !CONFIG_SMP for
    consistency.

Tested on AMD Milan platform and on a couple of Intel platforms.

Artem Bityutskiy (4):
  x86/smp: Allow calling mwait_play_dead with an arbitrary hint
  ACPI: processor_idle: Add FFH state handling
  intel_idle: Provide the default enter_dead() handler
  x86/smp: Eliminate mwait_play_dead_cpuid_hint()

 arch/x86/include/asm/smp.h    |  3 +++
 arch/x86/kernel/acpi/cstate.c | 10 ++++++++
 arch/x86/kernel/smpboot.c     | 44 ++++-------------------------------
 drivers/acpi/processor_idle.c |  2 ++
 drivers/idle/intel_idle.c     | 14 +++++++++++
 include/acpi/processor.h      |  5 ++++
 6 files changed, 39 insertions(+), 39 deletions(-)