ACPI: processor: introduce arch_has_acpi_pdc

arch dependent helper function that tells us if we should attempt to
evaluate _PDC on this machine or not.

The x86 implementation assumes that the CPUs in the machine must be
homogeneous, and that you cannot mix CPUs of different vendors.

Cc: Tony Luck <tony.luck@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h
index 60d2b2db0bc5..d787e6e92bd1 100644
--- a/arch/x86/include/asm/acpi.h
+++ b/arch/x86/include/asm/acpi.h
@@ -142,6 +142,13 @@ static inline unsigned int acpi_processor_cstate_check(unsigned int max_cstate)
                 return max_cstate;
 }
 
+static inline bool arch_has_acpi_pdc(void)
+{
+        struct cpuinfo_x86 *c = &cpu_data(0);
+        return (c->x86_vendor == X86_VENDOR_INTEL ||
+                c->x86_vendor == X86_VENDOR_CENTAUR);
+}
+
 #else /* !CONFIG_ACPI */
 
 #define acpi_lapic 0