linux-kernel - [PATCH V2 7/9] x86, amd: Factor out number of nodes calculation

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Message-ID: <1433277362-10911-8-git-send-email-Aravind.Gopalakrishnan@amd.com>
Date:	Tue, 2 Jun 2015 15:36:00 -0500
From:	Aravind Gopalakrishnan <Aravind.Gopalakrishnan@....com>
To:	<bp@...en8.de>, <dougthompson@...ssion.com>,
	<mchehab@....samsung.com>
CC:	<linux-edac@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<x86@...nel.org>, Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, Borislav Petkov <bp@...e.de>,
	Jacob Shin <jacob.w.shin@...il.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Andy Lutomirski <luto@...nel.org>,
	"Paolo Bonzini" <pbonzini@...hat.com>
Subject: [PATCH V2 7/9] x86, amd: Factor out number of nodes calculation

Factoring out number of nodes calculation out of amd_get_topology()
and saving the value in a static variable.

A later patch will introduce a accessor for this value so we
can use the information elsewhere in EDAC. The usage will be
included in a future patch too.

While at it, remove X86_HT #ifdefs around the code block for
amd_get_topology() and it's caller amd_detect_cmp(). Since
CONFIG_X86_HT defaults to Y, this code is always built-in.
Besides, amd_get_topology() extracts necessary info from
cpuid_[eax|ebx](0x8000001e) for platforms that are not 'HT'

Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Borislav Petkov <bp@...e.de>
Cc: Jacob Shin <jacob.w.shin@...il.com>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@....com>
---
 arch/x86/kernel/cpu/amd.c | 36 +++++++++++++++++++++++++++---------
 1 file changed, 27 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 94e7051..c595669 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -19,6 +19,13 @@
 
 #include "cpu.h"
 
+/*
+ * nodes_per_processor: Specifies number of nodes per socket
+ * Refer Fam15h Models 00-0fh BKDG-
+ *   CPUID Fn8000_001E_ECX Node Identifiers[10:8]
+ */
+static u32 nodes_per_processor = 1;
+
 static inline int rdmsrl_amd_safe(unsigned msr, unsigned long long *p)
 {
 	u32 gprs[8] = { 0 };
@@ -282,25 +289,40 @@ static int nearby_node(int apicid)
 }
 #endif
 
+static void amd_set_num_nodes(void)
+{
+	if (cpu_has_topoext) {
+		u32 ecx;
+
+		ecx = cpuid_ecx(0x8000001e);
+		nodes_per_processor = ((ecx >> 8) & 7) + 1;
+	} else if (static_cpu_has(X86_FEATURE_NODEID_MSR)) {
+		u64 value;
+
+		rdmsrl(MSR_FAM10H_NODE_ID, value);
+		nodes_per_processor = ((value >> 3) & 7) + 1;
+	}
+}
+
 /*
  * Fixup core topology information for
  * (1) AMD multi-node processors
  *     Assumption: Number of cores in each internal node is the same.
  * (2) AMD processors supporting compute units
  */
-#ifdef CONFIG_X86_HT
 static void amd_get_topology(struct cpuinfo_x86 *c)
 {
-	u32 nodes, cores_per_cu = 1;
+	u32 cores_per_cu = 1;
 	u8 node_id;
 	int cpu = smp_processor_id();
 
+	amd_set_num_nodes();
+
 	/* get information required for multi-node processors */
 	if (cpu_has_topoext) {
 		u32 eax, ebx, ecx, edx;
 
 		cpuid(0x8000001e, &eax, &ebx, &ecx, &edx);
-		nodes = ((ecx >> 8) & 7) + 1;
 		node_id = ecx & 7;
 
 		/* get compute unit information */
@@ -311,18 +333,17 @@ static void amd_get_topology(struct cpuinfo_x86 *c)
 		u64 value;
 
 		rdmsrl(MSR_FAM10H_NODE_ID, value);
-		nodes = ((value >> 3) & 7) + 1;
 		node_id = value & 7;
 	} else
 		return;
 
 	/* fixup multi-node processor information */
-	if (nodes > 1) {
+	if (nodes_per_processor > 1) {
 		u32 cores_per_node;
 		u32 cus_per_node;
 
 		set_cpu_cap(c, X86_FEATURE_AMD_DCM);
-		cores_per_node = c->x86_max_cores / nodes;
+		cores_per_node = c->x86_max_cores / nodes_per_processor;
 		cus_per_node = cores_per_node / cores_per_cu;
 
 		/* store NodeID, use llc_shared_map to store sibling info */
@@ -333,7 +354,6 @@ static void amd_get_topology(struct cpuinfo_x86 *c)
 		c->compute_unit_id %= cus_per_node;
 	}
 }
-#endif
 
 /*
  * On a AMD dual core setup the lower bits of the APIC id distinguish the cores.
@@ -341,7 +361,6 @@ static void amd_get_topology(struct cpuinfo_x86 *c)
  */
 static void amd_detect_cmp(struct cpuinfo_x86 *c)
 {
-#ifdef CONFIG_X86_HT
 	unsigned bits;
 	int cpu = smp_processor_id();
 
@@ -353,7 +372,6 @@ static void amd_detect_cmp(struct cpuinfo_x86 *c)
 	/* use socket ID also for last level cache */
 	per_cpu(cpu_llc_id, cpu) = c->phys_proc_id;
 	amd_get_topology(c);
-#endif
 }
 
 u16 amd_get_nb_id(int cpu)
-- 
2.4.0

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