Merge tag 'drm-msm-fixes-2018-04-25' of git://people.freedesktop.org/~robclark/linux...

[sfrench/cifs-2.6.git] / arch / x86 / kernel / smpboot.c

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index ff99e2b6fc541a0faf8afaa17328679533b7838a..45175b81dd5b371e188820fddefcfd5ee6c8bee9 100644 (file)
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -77,6 +77,8 @@
 #include <asm/i8259.h>
 #include <asm/misc.h>
 #include <asm/qspinlock.h>
+#include <asm/intel-family.h>
+#include <asm/cpu_device_id.h>
 
 /* Number of siblings per CPU package */
 int smp_num_siblings = 1;
@@ -390,15 +392,47 @@ static bool match_smt(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
        return false;
 }
 
+/*
+ * Define snc_cpu[] for SNC (Sub-NUMA Cluster) CPUs.
+ *
+ * These are Intel CPUs that enumerate an LLC that is shared by
+ * multiple NUMA nodes. The LLC on these systems is shared for
+ * off-package data access but private to the NUMA node (half
+ * of the package) for on-package access.
+ *
+ * CPUID (the source of the information about the LLC) can only
+ * enumerate the cache as being shared *or* unshared, but not
+ * this particular configuration. The CPU in this case enumerates
+ * the cache to be shared across the entire package (spanning both
+ * NUMA nodes).
+ */
+
+static const struct x86_cpu_id snc_cpu[] = {
+       { X86_VENDOR_INTEL, 6, INTEL_FAM6_SKYLAKE_X },
+       {}
+};
+
 static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
 {
        int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
 
-       if (per_cpu(cpu_llc_id, cpu1) != BAD_APICID &&
-           per_cpu(cpu_llc_id, cpu1) == per_cpu(cpu_llc_id, cpu2))
-               return topology_sane(c, o, "llc");
+       /* Do not match if we do not have a valid APICID for cpu: */
+       if (per_cpu(cpu_llc_id, cpu1) == BAD_APICID)
+               return false;
 
-       return false;
+       /* Do not match if LLC id does not match: */
+       if (per_cpu(cpu_llc_id, cpu1) != per_cpu(cpu_llc_id, cpu2))
+               return false;
+
+       /*
+        * Allow the SNC topology without warning. Return of false
+        * means 'c' does not share the LLC of 'o'. This will be
+        * reflected to userspace.
+        */
+       if (!topology_same_node(c, o) && x86_match_cpu(snc_cpu))
+               return false;
+
+       return topology_sane(c, o, "llc");
 }
 
 /*
@@ -456,7 +490,8 @@ static struct sched_domain_topology_level x86_topology[] = {
 
 /*
  * Set if a package/die has multiple NUMA nodes inside.
- * AMD Magny-Cours and Intel Cluster-on-Die have this.
+ * AMD Magny-Cours, Intel Cluster-on-Die, and Intel
+ * Sub-NUMA Clustering have this.
  */
 static bool x86_has_numa_in_package;