[PATCH v3 4/4] Add R3MWAIT to CPU features

From: Grzegorz Andrejczuk
Date: Thu Oct 13 2016 - 10:23:43 EST


Add cpu feature for ring 3 monitor/mwait.

Signed-off-by: Grzegorz Andrejczuk <grzegorz.andrejczuk@xxxxxxxxx>
---
arch/x86/include/asm/cpufeatures.h | 2 ++
arch/x86/kernel/cpu/common.c | 3 +++
arch/x86/kernel/cpu/intel.c | 1 +
3 files changed, 6 insertions(+)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 92a8308..02bfcc6 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -71,6 +71,8 @@
#define X86_FEATURE_RECOVERY ( 2*32+ 0) /* CPU in recovery mode */
#define X86_FEATURE_LONGRUN ( 2*32+ 1) /* Longrun power control */
#define X86_FEATURE_LRTI ( 2*32+ 3) /* LongRun table interface */
+/* non architectural Intel-defined CPU features not present in CPUID */
+#define X86_FEATURE_PHIR3MWAIT ( 2*32+ 4)

/* Other features, Linux-defined mapping, word 3 */
/* This range is used for feature bits which conflict or are synthesized */
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index ff26036..ce47687 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1108,6 +1108,9 @@ static void identify_cpu(struct cpuinfo_x86 *c)
#endif
/* The boot/hotplug time assigment got cleared, restore it */
c->logical_proc_id = topology_phys_to_logical_pkg(c->phys_proc_id);
+
+ if (cpu_has(c, X86_FEATURE_PHIR3MWAIT))
+ elf_hwcap2 |= HWCAP2_PHIR3MWAIT;
}

/*
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 464df22..d524a06 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -88,6 +88,7 @@ static void __init probe_xeon_phi_r3mwait(struct cpuinfo_x86 *c)
rdmsrl(MSR_PHI_MISC_THD_FEATURE, msr);
msr |= MSR_PHI_MISC_THD_FEATURE_R3MWAIT;
wrmsrl(MSR_PHI_MISC_THD_FEATURE, msr);
+ set_cpu_cap(c, X86_FEATURE_PHIR3MWAIT);
}
}

--
2.5.1