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-rw-r--r--arch/arm64/include/asm/cputype.h2
-rw-r--r--arch/arm64/kernel/topology.c47
2 files changed, 35 insertions, 14 deletions
diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h
index 27f54a7cc81b..ed48a3a7836a 100644
--- a/arch/arm64/include/asm/cputype.h
+++ b/arch/arm64/include/asm/cputype.h
@@ -18,6 +18,8 @@
#define INVALID_HWID ULONG_MAX
+#define MPIDR_UP_BITMASK (0x1 << 30)
+#define MPIDR_MT_BITMASK (0x1 << 24)
#define MPIDR_HWID_BITMASK 0xff00ffffff
#define MPIDR_LEVEL_BITS_SHIFT 3
diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
index 43514f905916..b6ee26b0939a 100644
--- a/arch/arm64/kernel/topology.c
+++ b/arch/arm64/kernel/topology.c
@@ -20,6 +20,7 @@
#include <linux/of.h>
#include <linux/sched.h>
+#include <asm/cputype.h>
#include <asm/topology.h>
static int __init get_cpu_for_node(struct device_node *node)
@@ -188,13 +189,9 @@ static int __init parse_dt_topology(void)
* Check that all cores are in the topology; the SMP code will
* only mark cores described in the DT as possible.
*/
- for_each_possible_cpu(cpu) {
- if (cpu_topology[cpu].cluster_id == -1) {
- pr_err("CPU%d: No topology information specified\n",
- cpu);
+ for_each_possible_cpu(cpu)
+ if (cpu_topology[cpu].cluster_id == -1)
ret = -EINVAL;
- }
- }
out_map:
of_node_put(map);
@@ -219,14 +216,6 @@ static void update_siblings_masks(unsigned int cpuid)
struct cpu_topology *cpu_topo, *cpuid_topo = &cpu_topology[cpuid];
int cpu;
- if (cpuid_topo->cluster_id == -1) {
- /*
- * DT does not contain topology information for this cpu.
- */
- pr_debug("CPU%u: No topology information configured\n", cpuid);
- return;
- }
-
/* update core and thread sibling masks */
for_each_possible_cpu(cpu) {
cpu_topo = &cpu_topology[cpu];
@@ -249,6 +238,36 @@ static void update_siblings_masks(unsigned int cpuid)
void store_cpu_topology(unsigned int cpuid)
{
+ struct cpu_topology *cpuid_topo = &cpu_topology[cpuid];
+ u64 mpidr;
+
+ if (cpuid_topo->cluster_id != -1)
+ goto topology_populated;
+
+ mpidr = read_cpuid_mpidr();
+
+ /* Uniprocessor systems can rely on default topology values */
+ if (mpidr & MPIDR_UP_BITMASK)
+ return;
+
+ /* Create cpu topology mapping based on MPIDR. */
+ if (mpidr & MPIDR_MT_BITMASK) {
+ /* Multiprocessor system : Multi-threads per core */
+ cpuid_topo->thread_id = MPIDR_AFFINITY_LEVEL(mpidr, 0);
+ cpuid_topo->core_id = MPIDR_AFFINITY_LEVEL(mpidr, 1);
+ cpuid_topo->cluster_id = MPIDR_AFFINITY_LEVEL(mpidr, 2);
+ } else {
+ /* Multiprocessor system : Single-thread per core */
+ cpuid_topo->thread_id = -1;
+ cpuid_topo->core_id = MPIDR_AFFINITY_LEVEL(mpidr, 0);
+ cpuid_topo->cluster_id = MPIDR_AFFINITY_LEVEL(mpidr, 1);
+ }
+
+ pr_debug("CPU%u: cluster %d core %d thread %d mpidr %#016llx\n",
+ cpuid, cpuid_topo->cluster_id, cpuid_topo->core_id,
+ cpuid_topo->thread_id, mpidr);
+
+topology_populated:
update_siblings_masks(cpuid);
}