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authorNathan Lynch <ntl@pobox.com>2008-07-27 15:24:54 +1000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2008-07-28 16:30:52 +1000
commite9efed3b80a83e44b98fc626f3268ae072550b84 (patch)
treecbe7cc897dc112e2eb93f9bbded5aa3a8e6e0bf3 /arch
parent440a0857e32a05979fb01fc59ea454a723e80e4b (diff)
powerpc: Make core id information available to userspace
Existing Open Firmware practice is to report each processor core as a separate node in the device tree. Report the value of the "reg" OF property corresponding to a logical CPU's device node as the core_id attribute in /sys/devices/system/cpu/cpu*/topology/core_id. Signed-off-by: Nathan Lynch <ntl@pobox.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/kernel/smp.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index f7a2f81b5b7..5337ca7bb64 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -380,6 +380,29 @@ int __cpuinit __cpu_up(unsigned int cpu)
return 0;
}
+/* Return the value of the reg property corresponding to the given
+ * logical cpu.
+ */
+int cpu_to_core_id(int cpu)
+{
+ struct device_node *np;
+ const int *reg;
+ int id = -1;
+
+ np = of_get_cpu_node(cpu, NULL);
+ if (!np)
+ goto out;
+
+ reg = of_get_property(np, "reg", NULL);
+ if (!reg)
+ goto out;
+
+ id = *reg;
+out:
+ of_node_put(np);
+ return id;
+}
+
/* Must be called when no change can occur to cpu_present_map,
* i.e. during cpu online or offline.
*/