[PATCH 03/11] x86 topology: Add CPUID.1F multi-die/package support

[Len Brown]

From: Len Brown <len.brown@xxxxxxxxx>

Some new systems have multiple software-visible die within each package.
The new CPUID.1F leaf can enumerate this multi-die/package topology.

CPUID.1F a super-set of the CPUID.B "Extended Toplogy Leaf",
and a common updated routine can parse either leaf.

Legacy systems without CPUID.1F, and systems without multi-die/package
hardware, will see no functional change from this patch series.

Multi-die/package systems will use CPUID.B before this patch,
and CPUID.1F after this patch.  In the CPUID.B case, all die appear
(incorrectly) to software as individual packages.  In the CPUID.1F case,
the package id's reflect reality, and die_id's become meaningful.

Subsequent patches in this series update the kernel to be multi-die aware.
In particular, some software needs to know the difference between
a die-scope MSR and a package-scope MSR.

Signed-off-by: Len Brown <len.brown@xxxxxxxxx>
Cc: linux-doc@xxxxxxxxxxxxxxx
Signed-off-by: Len Brown <len.brown@xxxxxxxxx>
---
 Documentation/x86/topology.txt   |  4 ++
 arch/x86/include/asm/processor.h |  4 +-
 arch/x86/kernel/cpu/topology.c   | 82 ++++++++++++++++++++++++--------
 arch/x86/kernel/smpboot.c        |  4 +-
 4 files changed, 73 insertions(+), 21 deletions(-)

diff --git a/Documentation/x86/topology.txt b/Documentation/x86/topology.txt
index 06b3cdbc4048..8107b6cfc9ea 100644
--- a/Documentation/x86/topology.txt
+++ b/Documentation/x86/topology.txt
@@ -46,6 +46,10 @@ The topology of a system is described in the units of:
 
     The number of cores in a package. This information is retrieved via CPUID.
 
+  - cpuinfo_x86.x86_max_dies:
+
+    The number of dies in a package. This information is retrieved via CPUID.
+
   - cpuinfo_x86.phys_proc_id:
 
     The physical ID of the package. This information is retrieved via CPUID
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 33051436c864..f2856fe03715 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -105,7 +105,8 @@ struct cpuinfo_x86 {
 	int			x86_power;
 	unsigned long		loops_per_jiffy;
 	/* cpuid returned max cores value: */
-	u16			 x86_max_cores;
+	u16			x86_max_cores;
+	u16			x86_max_dies;
 	u16			apicid;
 	u16			initial_apicid;
 	u16			x86_clflush_size;
@@ -117,6 +118,7 @@ struct cpuinfo_x86 {
 	u16			logical_proc_id;
 	/* Core id: */
 	u16			cpu_core_id;
+	u16			cpu_die_id;
 	/* Index into per_cpu list: */
 	u16			cpu_index;
 	u32			microcode;
diff --git a/arch/x86/kernel/cpu/topology.c b/arch/x86/kernel/cpu/topology.c
index 8f6c784141d1..6dce6ee77849 100644
--- a/arch/x86/kernel/cpu/topology.c
+++ b/arch/x86/kernel/cpu/topology.c
@@ -15,33 +15,61 @@
 /* leaf 0xb SMT level */
 #define SMT_LEVEL	0
 
-/* leaf 0xb sub-leaf types */
+/* extended topology sub-leaf types */
 #define INVALID_TYPE	0
 #define SMT_TYPE	1
 #define CORE_TYPE	2
+#define DIE_TYPE	5
 
 #define LEAFB_SUBTYPE(ecx)		(((ecx) >> 8) & 0xff)
 #define BITS_SHIFT_NEXT_LEVEL(eax)	((eax) & 0x1f)
 #define LEVEL_MAX_SIBLINGS(ebx)		((ebx) & 0xffff)
 
-int detect_extended_topology_early(struct cpuinfo_x86 *c)
-{
 #ifdef CONFIG_SMP
+/*
+ * Check if given CPUID extended toplogy "leaf" is implemented
+ */
+static int check_extended_topology_leaf(int leaf)
+{
 	unsigned int eax, ebx, ecx, edx;
 
-	if (c->cpuid_level < 0xb)
+	cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
+
+	if (ebx == 0 || (LEAFB_SUBTYPE(ecx) != SMT_TYPE))
 		return -1;
 
-	cpuid_count(0xb, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
+	return 0;
+}
+/*
+ * Return best CPUID Extended Toplogy Leaf supported
+ */
+static int detect_extended_topology_leaf(struct cpuinfo_x86 *c)
+{
+	if (c->cpuid_level >= 0x1f)
+		if (check_extended_topology_leaf(0x1f) == 0)
+			return 0x1f;
 
-	/*
-	 * check if the cpuid leaf 0xb is actually implemented.
-	 */
-	if (ebx == 0 || (LEAFB_SUBTYPE(ecx) != SMT_TYPE))
+	if (c->cpuid_level >= 0xb)
+		if (check_extended_topology_leaf(0xb) == 0)
+			return 0xb;
+
+	return -1;
+}
+#endif
+
+int detect_extended_topology_early(struct cpuinfo_x86 *c)
+{
+#ifdef CONFIG_SMP
+	unsigned int eax, ebx, ecx, edx;
+	int leaf;
+
+	leaf = detect_extended_topology_leaf(c);
+	if (leaf < 0)
 		return -1;
 
 	set_cpu_cap(c, X86_FEATURE_XTOPOLOGY);
 
+	cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
 	/*
 	 * initial apic id, which also represents 32-bit extended x2apic id.
 	 */
@@ -52,7 +80,7 @@ int detect_extended_topology_early(struct cpuinfo_x86 *c)
 }
 
 /*
- * Check for extended topology enumeration cpuid leaf 0xb and if it
+ * Check for extended topology enumeration cpuid leaf, and if it
  * exists, use it for populating initial_apicid and cpu topology
  * detection.
  */
@@ -60,46 +88,62 @@ int detect_extended_topology(struct cpuinfo_x86 *c)
 {
 #ifdef CONFIG_SMP
 	unsigned int eax, ebx, ecx, edx, sub_index;
-	unsigned int ht_mask_width, core_plus_mask_width;
+	unsigned int ht_mask_width, core_plus_mask_width, die_plus_mask_width;
 	unsigned int core_select_mask, core_level_siblings;
+	unsigned int die_select_mask, die_level_siblings;
+	int leaf;
 
-	if (detect_extended_topology_early(c) < 0)
+	leaf = detect_extended_topology_leaf(c);
+	if (leaf  < 0)
 		return -1;
 
 	/*
 	 * Populate HT related information from sub-leaf level 0.
 	 */
-	cpuid_count(0xb, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
+	cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
+	c->initial_apicid = edx;
 	core_level_siblings = smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx);
 	core_plus_mask_width = ht_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
+	die_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
+	die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
 
 	sub_index = 1;
 	do {
-		cpuid_count(0xb, sub_index, &eax, &ebx, &ecx, &edx);
+		cpuid_count(leaf, sub_index, &eax, &ebx, &ecx, &edx);
 
 		/*
 		 * Check for the Core type in the implemented sub leaves.
 		 */
 		if (LEAFB_SUBTYPE(ecx) == CORE_TYPE) {
 			core_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
+			die_level_siblings = core_level_siblings;
 			core_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
-			break;
+		}
+		if (LEAFB_SUBTYPE(ecx) == DIE_TYPE) {
+			die_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
+			die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
 		}
 
 		sub_index++;
 	} while (LEAFB_SUBTYPE(ecx) != INVALID_TYPE);
 
 	core_select_mask = (~(-1 << core_plus_mask_width)) >> ht_mask_width;
-
-	c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid, ht_mask_width)
-						 & core_select_mask;
-	c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, core_plus_mask_width);
+	die_select_mask = (~(-1 << die_plus_mask_width)) >>
+				core_plus_mask_width;
+
+	c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid,
+				ht_mask_width) & core_select_mask;
+	c->cpu_die_id = apic->phys_pkg_id(c->initial_apicid,
+				core_plus_mask_width) & die_select_mask;
+	c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid,
+				die_plus_mask_width);
 	/*
 	 * Reinit the apicid, now that we have extended initial_apicid.
 	 */
 	c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);
 
 	c->x86_max_cores = (core_level_siblings / smp_num_siblings);
+	c->x86_max_dies = (die_level_siblings / core_level_siblings);
 #endif
 	return 0;
 }
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index ccd1f2a8e557..4250a87f57db 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -393,6 +393,7 @@ static bool match_smt(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
 		int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
 
 		if (c->phys_proc_id == o->phys_proc_id &&
+		    c->cpu_die_id == o->cpu_die_id &&
 		    per_cpu(cpu_llc_id, cpu1) == per_cpu(cpu_llc_id, cpu2)) {
 			if (c->cpu_core_id == o->cpu_core_id)
 				return topology_sane(c, o, "smt");
@@ -404,6 +405,7 @@ static bool match_smt(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
 		}
 
 	} else if (c->phys_proc_id == o->phys_proc_id &&
+		   c->cpu_die_id == o->cpu_die_id &&
 		   c->cpu_core_id == o->cpu_core_id) {
 		return topology_sane(c, o, "smt");
 	}
@@ -461,7 +463,7 @@ static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
  */
 static bool match_die(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
 {
-	if (c->phys_proc_id == o->phys_proc_id)
+	if (c->cpu_die_id == o->cpu_die_id)
 		return true;
 	return false;
 }
-- 
2.18.0-rc0