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powerpc/pseries: Export raw per-CPU VPA data via debugfs 

This patch exports the raw per-CPU VPA data via debugfs.
A per-CPU file is created which exports the VPA data of
that CPU to help debug some of the VPA related issues or
to analyze the per-CPU VPA related statistics.

v3: Removed offline CPU check.

v2: Included offline CPU check and other review comments.

Signed-off-by: Aravinda Prasad <aravinda@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Aravinda Prasad 2018-10-16 17:20:05 +05:30 committed by Michael Ellerman
parent d2bf793237
commit c6c26fb55e
1 changed files with 54 additions and 0 deletions
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54
arch/powerpc/platforms/pseries/lpar.c
View File

@ -48,6 +48,7 @@
#include <asm/kexec.h>
#include <asm/fadump.h>
#include <asm/asm-prototypes.h>
#include <asm/debugfs.h>
#include "pseries.h"
@ -1239,3 +1240,56 @@ static int __init reserve_vrma_context_id(void)
return 0;
}
machine_device_initcall(pseries, reserve_vrma_context_id);
#ifdef CONFIG_DEBUG_FS
/* debugfs file interface for vpa data */
static ssize_t vpa_file_read(struct file *filp, char __user *buf, size_t len,
loff_t *pos)
{
int cpu = (long)filp->private_data;
struct lppaca *lppaca = &lppaca_of(cpu);
return simple_read_from_buffer(buf, len, pos, lppaca,
sizeof(struct lppaca));
}
static const struct file_operations vpa_fops = {
.open = simple_open,
.read = vpa_file_read,
.llseek = default_llseek,
};
static int __init vpa_debugfs_init(void)
{
char name[16];
long i;
static struct dentry *vpa_dir;
if (!firmware_has_feature(FW_FEATURE_SPLPAR))
return 0;
vpa_dir = debugfs_create_dir("vpa", powerpc_debugfs_root);
if (!vpa_dir) {
pr_warn("%s: can't create vpa root dir\n", __func__);
return -ENOMEM;
}
/* set up the per-cpu vpa file*/
for_each_possible_cpu(i) {
struct dentry *d;
sprintf(name, "cpu-%ld", i);
d = debugfs_create_file(name, 0400, vpa_dir, (void *)i,
&vpa_fops);
if (!d) {
pr_warn("%s: can't create per-cpu vpa file\n",
__func__);
return -ENOMEM;
}
}
return 0;
}
machine_arch_initcall(pseries, vpa_debugfs_init);
#endif /* CONFIG_DEBUG_FS */