ACPI: processor: Introduce acpi_processor_osc()

The processor _OSC method is already used for a workaround introduced
in commit a21211672c9a ("ACPI / processor: Request native thermal
interrupt handling via _OSC"), but in accordance with ACPI 6.5 (and
earlier), it should be used for negotiating all of the processor
capabilities instead of _PDC (which has been deprecated since ACPI 3.0
and got removed from ACPI 6.5 entirely).

Create a new callback function called acpi_processor_osc() to be invoked
for every processor object and processor device in the ACPI namespace, in
analogy with the already existing acpi_hwp_native_thermal_lvt_osc().

Make this function implement the workaround mentioned above and convey
all of the OSPM processor support information to the platform firmware
by setting all of the appropriate processor capabilities bits before
evaluating _OSC for the given processor. For this purpose, make it
call arch_acpi_set_proc_cap_bits() and modify the latter to set
ACPI_PROC_CAP_COLLAB_PROC_PERF along with the other processor
capabilities bits.

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Michal Wilczynski <michal.wilczynski@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[ rjw: Subject and changelog edits, whitespace fixup ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h
index 6f6752a2ea36..6c3af9486153 100644
--- a/arch/x86/include/asm/acpi.h
+++ b/arch/x86/include/asm/acpi.h
@@ -115,6 +115,9 @@ static inline void arch_acpi_set_proc_cap_bits(u32 *cap)
 	if (cpu_has(c, X86_FEATURE_ACPI))
 		*cap |= ACPI_PROC_CAP_T_FFH;
 
+	if (cpu_has(c, X86_FEATURE_HWP))
+		*cap |= ACPI_PROC_CAP_COLLAB_PROC_PERF;
+
 	/*
 	 * If mwait/monitor is unsupported, C_C1_FFH and
 	 * C2/C3_FFH will be disabled.