Commit-ID: ee6825c80e870fff1a370c718ec77022ade0889b
Gitweb: http://git.kernel.org/tip/ee6825c80e870fff1a370c718ec77022ade0889b
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Fri, 25 Mar 2016 15:52:34 +0100
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue, 29 Mar 2016 10:45:04 +0200
x86/topology: Fix AMD core count
It turns out AMD gets x86_max_cores wrong when there are compute
units.
The issue is that Linux assumes:
nr_logical_cpus = nr_cores * nr_siblings
But AMD reports its CU unit as 2 cores, but then sets num_smp_siblings
to 2 as well.
Boris: fixup ras/mce_amd_inj.c too, to compute the Node Base Core
properly, according to the new nomenclature.
Fixes: 1f12e32f4cd5 ("x86/topology: Create logical package id")
Reported-by: Xiong Zhou <jencce.kernel@xxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Andreas Herrmann <aherrmann@xxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/20160317095220.GO6344@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/include/asm/smp.h | 1 +
arch/x86/kernel/cpu/amd.c | 8 ++++----
arch/x86/ras/mce_amd_inj.c | 3 ++-
3 files changed, 7 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 20a3de5..66b0573 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -155,6 +155,7 @@ static inline int wbinvd_on_all_cpus(void)
wbinvd();
return 0;
}
+#define smp_num_siblings 1
#endif /* CONFIG_SMP */
extern unsigned disabled_cpus;
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 6e47e3a..4d0087f 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -312,9 +312,9 @@ static void amd_get_topology(struct cpuinfo_x86 *c)
node_id = ecx & 7;
/* get compute unit information */
- smp_num_siblings = ((ebx >> 8) & 3) + 1;
+ cores_per_cu = smp_num_siblings = ((ebx >> 8) & 3) + 1;
+ c->x86_max_cores /= smp_num_siblings;
c->compute_unit_id = ebx & 0xff;
- cores_per_cu += ((ebx >> 8) & 3);
} else if (cpu_has(c, X86_FEATURE_NODEID_MSR)) {
u64 value;
@@ -329,8 +329,8 @@ static void amd_get_topology(struct cpuinfo_x86 *c)
u32 cus_per_node;
set_cpu_cap(c, X86_FEATURE_AMD_DCM);
- cores_per_node = c->x86_max_cores / nodes_per_socket;
- cus_per_node = cores_per_node / cores_per_cu;
+ cus_per_node = c->x86_max_cores / nodes_per_socket;
+ cores_per_node = cus_per_node * cores_per_cu;
/* store NodeID, use llc_shared_map to store sibling info */
per_cpu(cpu_llc_id, cpu) = node_id;
diff --git a/arch/x86/ras/mce_amd_inj.c b/arch/x86/ras/mce_amd_inj.c
index 55d38cf..9e02dca 100644
--- a/arch/x86/ras/mce_amd_inj.c
+++ b/arch/x86/ras/mce_amd_inj.c
@@ -20,6 +20,7 @@
#include <linux/pci.h>
#include <asm/mce.h>
+#include <asm/smp.h>
#include <asm/amd_nb.h>
#include <asm/irq_vectors.h>
@@ -206,7 +207,7 @@ static u32 get_nbc_for_node(int node_id)
struct cpuinfo_x86 *c = &boot_cpu_data;
u32 cores_per_node;
- cores_per_node = c->x86_max_cores / amd_get_nodes_per_socket();
+ cores_per_node = (c->x86_max_cores * smp_num_siblings) / amd_get_nodes_per_socket();
return cores_per_node * node_id;
}
--
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