hypfs_diag0c.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Hypervisor filesystem for Linux on s390
  4 *
  5 * Diag 0C implementation
  6 *
  7 * Copyright IBM Corp. 2014
  8 */
  9
 10#include <linux/slab.h>
 11#include <linux/cpu.h>
 12#include <asm/machine.h>
 13#include <asm/diag.h>
 14#include <asm/hypfs.h>
 15#include "hypfs.h"
 16
 17#define DBFS_D0C_HDR_VERSION 0
 18
 19/*
 20 * Get hypfs_diag0c_entry from CPU vector and store diag0c data
 21 */
 22static void diag0c_fn(void *data)
 23{
 24	diag0c(((void **)data)[smp_processor_id()]);
 25}
 26
 27/*
 28 * Allocate buffer and store diag 0c data
 29 */
 30static void *diag0c_store(unsigned int *count)
 31{
 32	struct hypfs_diag0c_data *diag0c_data;
 33	unsigned int cpu_count, cpu, i;
 34	void **cpu_vec;
 35
 36	cpus_read_lock();
 37	cpu_count = num_online_cpus();
 38	cpu_vec = kmalloc_array(num_possible_cpus(), sizeof(*cpu_vec),
 39				GFP_KERNEL);
 40	if (!cpu_vec)
 41		goto fail_unlock_cpus;
 42	/* Note: Diag 0c needs 8 byte alignment and real storage */
 43	diag0c_data = kzalloc(struct_size(diag0c_data, entry, cpu_count),
 44			      GFP_KERNEL | GFP_DMA);
 45	if (!diag0c_data)
 46		goto fail_kfree_cpu_vec;
 47	i = 0;
 48	/* Fill CPU vector for each online CPU */
 49	for_each_online_cpu(cpu) {
 50		diag0c_data->entry[i].cpu = cpu;
 51		cpu_vec[cpu] = &diag0c_data->entry[i++];
 52	}
 53	/* Collect data all CPUs */
 54	on_each_cpu(diag0c_fn, cpu_vec, 1);
 55	*count = cpu_count;
 56	kfree(cpu_vec);
 57	cpus_read_unlock();
 58	return diag0c_data;
 59
 60fail_kfree_cpu_vec:
 61	kfree(cpu_vec);
 62fail_unlock_cpus:
 63	cpus_read_unlock();
 64	return ERR_PTR(-ENOMEM);
 65}
 66
 67/*
 68 * Hypfs DBFS callback: Free diag 0c data
 69 */
 70static void dbfs_diag0c_free(const void *data)
 71{
 72	kfree(data);
 73}
 74
 75/*
 76 * Hypfs DBFS callback: Create diag 0c data
 77 */
 78static int dbfs_diag0c_create(void **data, void **data_free_ptr, size_t *size)
 79{
 80	struct hypfs_diag0c_data *diag0c_data;
 81	unsigned int count;
 82
 83	diag0c_data = diag0c_store(&count);
 84	if (IS_ERR(diag0c_data))
 85		return PTR_ERR(diag0c_data);
 86	memset(&diag0c_data->hdr, 0, sizeof(diag0c_data->hdr));
 87	store_tod_clock_ext((union tod_clock *)diag0c_data->hdr.tod_ext);
 88	diag0c_data->hdr.len = count * sizeof(struct hypfs_diag0c_entry);
 89	diag0c_data->hdr.version = DBFS_D0C_HDR_VERSION;
 90	diag0c_data->hdr.count = count;
 91	*data = diag0c_data;
 92	*data_free_ptr = diag0c_data;
 93	*size = diag0c_data->hdr.len + sizeof(struct hypfs_diag0c_hdr);
 94	return 0;
 95}
 96
 97/*
 98 * Hypfs DBFS file structure
 99 */
100static struct hypfs_dbfs_file dbfs_file_0c = {
101	.name		= "diag_0c",
102	.data_create	= dbfs_diag0c_create,
103	.data_free	= dbfs_diag0c_free,
104};
105
106/*
107 * Initialize diag 0c interface for z/VM
108 */
109int __init hypfs_diag0c_init(void)
110{
111	if (!machine_is_vm())
112		return 0;
113	hypfs_dbfs_create_file(&dbfs_file_0c);
114	return 0;
115}
116
117/*
118 * Shutdown diag 0c interface for z/VM
119 */
120void hypfs_diag0c_exit(void)
121{
122	if (!machine_is_vm())
123		return;
124	hypfs_dbfs_remove_file(&dbfs_file_0c);
125}