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Commit ee35e01b authored by Aravinda Prasad's avatar Aravinda Prasad Committed by Greg Kroah-Hartman
Browse files

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



[ Upstream commit c6c26fb55e8e4b3fc376be5611685990a17de27a ]

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: default avatarAravinda Prasad <aravinda@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 9ed143cf

arch/powerpc/platforms/pseries/lpar.c

+54 −0
Original line number Original line Diff line number Diff line
@@ -48,6 +48,7 @@ 
#include <asm/kexec.h>

#include <asm/kexec.h>

#include <asm/fadump.h>

#include <asm/fadump.h>

#include <asm/asm-prototypes.h>

#include <asm/asm-prototypes.h>

#include <asm/debugfs.h>





#include "pseries.h"

#include "pseries.h"
@@ -1032,3 +1033,56 @@ static int __init reserve_vrma_context_id(void) 
	return 0;

	return 0;

}

}

machine_device_initcall(pseries, reserve_vrma_context_id);

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 */