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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>
This commit is contained in:
Nathan Lynch 2008-07-27 15:24:54 +10:00 committed by Benjamin Herrenschmidt
parent 440a0857e3
commit e9efed3b80
3 changed files with 25 additions and 0 deletions
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23
arch/powerpc/kernel/smp.c
View File

@ -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.
*/

1
include/asm-powerpc/smp.h
View File

@ -63,6 +63,7 @@ extern int smp_hw_index[];
DECLARE_PER_CPU(cpumask_t, cpu_sibling_map);
DECLARE_PER_CPU(cpumask_t, cpu_core_map);
extern int cpu_to_core_id(int cpu);
/* Since OpenPIC has only 4 IPIs, we use slightly different message numbers.
*

1
include/asm-powerpc/topology.h
View File

@ -109,6 +109,7 @@ static inline void sysfs_remove_device_from_node(struct sys_device *dev,
#define topology_thread_siblings(cpu) (per_cpu(cpu_sibling_map, cpu))
#define topology_core_siblings(cpu) (per_cpu(cpu_core_map, cpu))
#define topology_core_id(cpu) (cpu_to_core_id(cpu))
#endif
#endif