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Subject[PATCH v2] x86, amd: Get multi-node CPU info from NodeId MSR instead of PCI config space

Use NodeId MSR to get NodeId and number of nodes per processor.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
---
arch/x86/include/asm/cpufeature.h | 1 +
arch/x86/include/asm/msr-index.h | 1 +
arch/x86/kernel/cpu/amd.c | 53 ++++++++++--------------------------
3 files changed, 17 insertions(+), 38 deletions(-)
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 613700f..637e1ec 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -153,6 +153,7 @@
#define X86_FEATURE_SSE5 (6*32+11) /* SSE-5 */
#define X86_FEATURE_SKINIT (6*32+12) /* SKINIT/STGI instructions */
#define X86_FEATURE_WDT (6*32+13) /* Watchdog timer */
+#define X86_FEATURE_NODEID_MSR (6*32+19) /* NodeId MSR */

/*
* Auxiliary flags: Linux defined - For features scattered in various
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 4ffe09b..9d976a7 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -123,6 +123,7 @@
#define FAM10H_MMIO_CONF_BUSRANGE_SHIFT 2
#define FAM10H_MMIO_CONF_BASE_MASK 0xfffffff
#define FAM10H_MMIO_CONF_BASE_SHIFT 20
+#define MSR_FAM10H_NODE_ID 0xc001100c

/* K8 MSRs */
#define MSR_K8_TOP_MEM1 0xc001001a
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 7128b37..5dcd638 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -254,59 +254,36 @@ static int __cpuinit nearby_node(int apicid)

/*
* Fixup core topology information for AMD multi-node processors.
- * Assumption 1: Number of cores in each internal node is the same.
- * Assumption 2: Mixed systems with both single-node and dual-node
- * processors are not supported.
+ * Assumption: Number of cores in each internal node is the same.
*/
#ifdef CONFIG_X86_HT
static void __cpuinit amd_fixup_dcm(struct cpuinfo_x86 *c)
{
-#ifdef CONFIG_PCI
- u32 t, cpn;
- u8 n, n_id;
+ unsigned long long value;
+ u32 nodes, cores_per_node;
int cpu = smp_processor_id();

+ if (!cpu_has(c, X86_FEATURE_NODEID_MSR))
+ return;
+
/* fixup topology information only once for a core */
if (cpu_has(c, X86_FEATURE_AMD_DCM))
return;

- /* check for multi-node processor on boot cpu */
- t = read_pci_config(0, 24, 3, 0xe8);
- if (!(t & (1 << 29)))
+ rdmsrl(MSR_FAM10H_NODE_ID, value);
+
+ nodes = ((value >> 3) & 7) + 1;
+ if (nodes == 1)
return;

set_cpu_cap(c, X86_FEATURE_AMD_DCM);
+ cores_per_node = c->x86_max_cores / nodes;

- /* cores per node: each internal node has half the number of cores */
- cpn = c->x86_max_cores >> 1;
+ /* store NodeID, use llc_shared_map to store sibling info */
+ per_cpu(cpu_llc_id, cpu) = value & 7;

- /* even-numbered NB_id of this dual-node processor */
- n = c->phys_proc_id << 1;
-
- /*
- * determine internal node id and assign cores fifty-fifty to
- * each node of the dual-node processor
- */
- t = read_pci_config(0, 24 + n, 3, 0xe8);
- n = (t>>30) & 0x3;
- if (n == 0) {
- if (c->cpu_core_id < cpn)
- n_id = 0;
- else
- n_id = 1;
- } else {
- if (c->cpu_core_id < cpn)
- n_id = 1;
- else
- n_id = 0;
- }
-
- /* compute entire NodeID, use llc_shared_map to store sibling info */
- per_cpu(cpu_llc_id, cpu) = (c->phys_proc_id << 1) + n_id;
-
- /* fixup core id to be in range from 0 to cpn */
- c->cpu_core_id = c->cpu_core_id % cpn;
-#endif
+ /* fixup core id to be in range from 0 to (cores_per_node - 1) */
+ c->cpu_core_id = c->cpu_core_id % cores_per_node;
}
#endif

--
1.6.5.3


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