From e9efed3b80a83e44b98fc626f3268ae072550b84 Mon Sep 17 00:00:00 2001 From: Nathan Lynch Date: Sun, 27 Jul 2008 15:24:54 +1000 Subject: 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 Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/smp.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) (limited to 'arch/powerpc') 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. */ -- cgit v1.2.3