Commit e04fa612 authored by Nathan Fontenot's avatar Nathan Fontenot Committed by Benjamin Herrenschmidt
Browse files

powerpc/pseries: Add /proc interface to control topology updates



There are instances in which we do not want topology updates to occur.
In order to allow this a /proc interface (/proc/powerpc/topology_updates)
is introduced so that topology updates can be enabled and disabled.

This patch also adds a prrn_is_enabled() call so that PRRN events are
handled in the kernel only if topology updating is enabled.

Signed-off-by: default avatarNathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 1b1218d3
......@@ -71,6 +71,7 @@ static inline void sysfs_remove_device_from_node(struct device *dev,
#if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR)
extern int start_topology_update(void);
extern int stop_topology_update(void);
extern int prrn_is_enabled(void);
#else
static inline int start_topology_update(void)
{
......@@ -80,6 +81,10 @@ static inline int stop_topology_update(void)
{
return 0;
}
static inline int prrn_is_enabled(void)
{
return 0;
}
#endif /* CONFIG_NUMA && CONFIG_PPC_SPLPAR */
#include <asm-generic/topology.h>
......
......@@ -29,6 +29,7 @@
#include <asm/nvram.h>
#include <linux/atomic.h>
#include <asm/machdep.h>
#include <asm/topology.h>
static DEFINE_SPINLOCK(rtasd_log_lock);
......@@ -292,11 +293,13 @@ void prrn_schedule_update(u32 scope)
static void handle_rtas_event(const struct rtas_error_log *log)
{
if (log->type == RTAS_TYPE_PRRN)
if (log->type == RTAS_TYPE_PRRN) {
/* For PRRN Events the extended log length is used to denote
* the scope for calling rtas update-nodes.
*/
prrn_schedule_update(log->extended_log_length);
if (prrn_is_enabled())
prrn_schedule_update(log->extended_log_length);
}
return;
}
......
......@@ -23,6 +23,9 @@
#include <linux/cpuset.h>
#include <linux/node.h>
#include <linux/stop_machine.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
#include <asm/sparsemem.h>
#include <asm/prom.h>
#include <asm/smp.h>
......@@ -1585,7 +1588,6 @@ int start_topology_update(void)
return rc;
}
__initcall(start_topology_update);
/*
* Disable polling for VPHN associativity changes.
......@@ -1604,4 +1606,62 @@ int stop_topology_update(void)
return rc;
}
int prrn_is_enabled(void)
{
return prrn_enabled;
}
static int topology_read(struct seq_file *file, void *v)
{
if (vphn_enabled || prrn_enabled)
seq_puts(file, "on\n");
else
seq_puts(file, "off\n");
return 0;
}
static int topology_open(struct inode *inode, struct file *file)
{
return single_open(file, topology_read, NULL);
}
static ssize_t topology_write(struct file *file, const char __user *buf,
size_t count, loff_t *off)
{
char kbuf[4]; /* "on" or "off" plus null. */
int read_len;
read_len = count < 3 ? count : 3;
if (copy_from_user(kbuf, buf, read_len))
return -EINVAL;
kbuf[read_len] = '\0';
if (!strncmp(kbuf, "on", 2))
start_topology_update();
else if (!strncmp(kbuf, "off", 3))
stop_topology_update();
else
return -EINVAL;
return count;
}
static const struct file_operations topology_ops = {
.read = seq_read,
.write = topology_write,
.open = topology_open,
.release = single_release
};
static int topology_update_init(void)
{
start_topology_update();
proc_create("powerpc/topology_updates", 644, NULL, &topology_ops);
return 0;
}
device_initcall(topology_update_init);
#endif /* CONFIG_PPC_SPLPAR */
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