Merge branch 'x86-process-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pul x86/process updates from Ingo Molnar:
 "The main change in this cycle was to add the ARCH_[GET|SET]_CPUID
  prctl() ABI extension to control the availability of the CPUID
  instruction, analogously to the existing PR_GET|SET_TSC ABI that
  controls RDTSC.

  Motivation: the 'rr' user-space record-and-replay execution debugger
  would like to trap and emulate the CPUID instruction - which
  instruction is normally unprivileged.

  Trapping CPUID is possible on IvyBridge and later Intel CPUs - expose
  this hardware capability"

* 'x86-process-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/syscalls/32: Ignore arch_prctl for other architectures
  um/arch_prctl: Fix fallout from x86 arch_prctl() rework
  x86/arch_prctl: Add ARCH_[GET|SET]_CPUID
  x86/cpufeature: Detect CPUID faulting support
  x86/syscalls/32: Wire up arch_prctl on x86-32
  x86/arch_prctl: Add do_arch_prctl_common()
  x86/arch_prctl/64: Rename do_arch_prctl() to do_arch_prctl_64()
  x86/arch_prctl/64: Use SYSCALL_DEFINE2 to define sys_arch_prctl()
  x86/arch_prctl: Rename 'code' argument to 'option'
  x86/msr: Rename MISC_FEATURE_ENABLES to MISC_FEATURES_ENABLES
  x86/process: Optimize TIF_NOTSC switch
  x86/process: Correct and optimize TIF_BLOCKSTEP switch
  x86/process: Optimize TIF checks in __switch_to_xtra()

1 files changed, 32 insertions, 8 deletions

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 063197771b8d..dfa90a3a5145 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -90,16 +90,12 @@ static void probe_xeon_phi_r3mwait(struct cpuinfo_x86 *c)
 		return;
 	}
 
-	if (ring3mwait_disabled) {
-		msr_clear_bit(MSR_MISC_FEATURE_ENABLES,
-			      MSR_MISC_FEATURE_ENABLES_RING3MWAIT_BIT);
+	if (ring3mwait_disabled)
 		return;
-	}
-
-	msr_set_bit(MSR_MISC_FEATURE_ENABLES,
-		    MSR_MISC_FEATURE_ENABLES_RING3MWAIT_BIT);
 
 	set_cpu_cap(c, X86_FEATURE_RING3MWAIT);
+	this_cpu_or(msr_misc_features_shadow,
+		    1UL << MSR_MISC_FEATURES_ENABLES_RING3MWAIT_BIT);
 
 	if (c == &boot_cpu_data)
 		ELF_HWCAP2 |= HWCAP2_RING3MWAIT;
@@ -488,6 +484,34 @@ static void intel_bsp_resume(struct cpuinfo_x86 *c)
 	init_intel_energy_perf(c);
 }
 
+static void init_cpuid_fault(struct cpuinfo_x86 *c)
+{
+	u64 msr;
+
+	if (!rdmsrl_safe(MSR_PLATFORM_INFO, &msr)) {
+		if (msr & MSR_PLATFORM_INFO_CPUID_FAULT)
+			set_cpu_cap(c, X86_FEATURE_CPUID_FAULT);
+	}
+}
+
+static void init_intel_misc_features(struct cpuinfo_x86 *c)
+{
+	u64 msr;
+
+	if (rdmsrl_safe(MSR_MISC_FEATURES_ENABLES, &msr))
+		return;
+
+	/* Clear all MISC features */
+	this_cpu_write(msr_misc_features_shadow, 0);
+
+	/* Check features and update capabilities and shadow control bits */
+	init_cpuid_fault(c);
+	probe_xeon_phi_r3mwait(c);
+
+	msr = this_cpu_read(msr_misc_features_shadow);
+	wrmsrl(MSR_MISC_FEATURES_ENABLES, msr);
+}
+
 static void init_intel(struct cpuinfo_x86 *c)
 {
 	unsigned int l2 = 0;
@@ -602,7 +626,7 @@ static void init_intel(struct cpuinfo_x86 *c)
 
 	init_intel_energy_perf(c);
 
-	probe_xeon_phi_r3mwait(c);
+	init_intel_misc_features(c);
 }
 
 #ifdef CONFIG_X86_32