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

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  [PATCH v3 4/4] Add R3MWAIT to CPU features Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com> - 2016-10-13 16:30 +0200
    Re: [PATCH v3 4/4] Add R3MWAIT to CPU features Thomas Gleixner <tglx@linutronix.de> - 2016-10-13 17:50 +0200

#1500298 — [PATCH v3 4/4] Add R3MWAIT to CPU features

Add cpu feature for ring 3 monitor/mwait.

Signed-off-by: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com>
---
 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

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#1500371

On Thu, 13 Oct 2016, Grzegorz Andrejczuk wrote:
> --- 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;

Why can't you just set that bit in probe_xeon_phi_r3mwait()?

Just because its so much fun to sprinkle code at random places, right?

Sigh.

	tglx

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