[PATCH v6: 4/4] x86/cpufeature: Add R3MWAIT to CPU features

From: Grzegorz Andrejczuk
Date: Thu Oct 27 2016 - 10:02:42 EST


Add cpu feature for ring 3 monitor/mwait.
Set HWCAP2 1st bit during init.

Signed-off-by: Grzegorz Andrejczuk <grzegorz.andrejczuk@xxxxxxxxx>
---
arch/x86/include/asm/cpufeatures.h | 2 ++
arch/x86/kernel/cpu/intel.c | 4 ++++
2 files changed, 6 insertions(+)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 92a8308..d430200 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 */
+/* Xeon Phi x200 ring 3 MONITOR/MWAIT enabled */
+#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/intel.c b/arch/x86/kernel/cpu/intel.c
index 2140ed3..3f02c7e 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -14,6 +14,8 @@
#include <asm/bugs.h>
#include <asm/cpu.h>
#include <asm/intel-family.h>
+#include <asm/hwcap2.h>
+#include <asm/elf.h>

#ifdef CONFIG_X86_64
#include <linux/topology.h>
@@ -84,6 +86,8 @@ static void probe_xeon_phi_r3mwait(struct cpuinfo_x86 *c)
} else {
msr |= MSR_PHI_MISC_THD_FEATURE_R3MWAIT;
wrmsrl(MSR_PHI_MISC_THD_FEATURE, msr);
+ set_cpu_cap(c, X86_FEATURE_PHIR3MWAIT);
+ ELF_HWCAP2 |= HWCAP2_PHIR3MWAIT;
}
}

--
2.5.1