1// SPDX-License-Identifier: GPL-2.0
2/*
3 *    Hypervisor filesystem for Linux on s390.
4 *    Set Partition-Resource Parameter interface.
5 *
6 *    Copyright IBM Corp. 2013
7 *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
8 */
9
10#include <linux/compat.h>
11#include <linux/errno.h>
12#include <linux/gfp.h>
13#include <linux/string.h>
14#include <linux/types.h>
15#include <linux/uaccess.h>
16#include <asm/diag.h>
17#include <asm/sclp.h>
18#include "hypfs.h"
19
20#define DIAG304_SET_WEIGHTS	0
21#define DIAG304_QUERY_PRP	1
22#define DIAG304_SET_CAPPING	2
23
24#define DIAG304_CMD_MAX		2
25
26static inline unsigned long __hypfs_sprp_diag304(void *data, unsigned long cmd)
27{
28	register unsigned long _data asm("2") = (unsigned long) data;
29	register unsigned long _rc asm("3");
30	register unsigned long _cmd asm("4") = cmd;
31
32	asm volatile("diag %1,%2,0x304\n"
33		     : "=d" (_rc) : "d" (_data), "d" (_cmd) : "memory");
34
35	return _rc;
36}
37
38static unsigned long hypfs_sprp_diag304(void *data, unsigned long cmd)
39{
40	diag_stat_inc(DIAG_STAT_X304);
41	return __hypfs_sprp_diag304(data, cmd);
42}
43
44static void hypfs_sprp_free(const void *data)
45{
46	free_page((unsigned long) data);
47}
48
49static int hypfs_sprp_create(void **data_ptr, void **free_ptr, size_t *size)
50{
51	unsigned long rc;
52	void *data;
53
54	data = (void *) get_zeroed_page(GFP_KERNEL);
55	if (!data)
56		return -ENOMEM;
57	rc = hypfs_sprp_diag304(data, DIAG304_QUERY_PRP);
58	if (rc != 1) {
59		*data_ptr = *free_ptr = NULL;
60		*size = 0;
61		free_page((unsigned long) data);
62		return -EIO;
63	}
64	*data_ptr = *free_ptr = data;
65	*size = PAGE_SIZE;
66	return 0;
67}
68
69static int __hypfs_sprp_ioctl(void __user *user_area)
70{
71	struct hypfs_diag304 *diag304;
72	unsigned long cmd;
73	void __user *udata;
74	void *data;
75	int rc;
76
77	rc = -ENOMEM;
78	data = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
79	diag304 = kzalloc(sizeof(*diag304), GFP_KERNEL);
80	if (!data || !diag304)
81		goto out;
82
83	rc = -EFAULT;
84	if (copy_from_user(diag304, user_area, sizeof(*diag304)))
85		goto out;
86	rc = -EINVAL;
87	if ((diag304->args[0] >> 8) != 0 || diag304->args[1] > DIAG304_CMD_MAX)
88		goto out;
89
90	rc = -EFAULT;
91	udata = (void __user *)(unsigned long) diag304->data;
92	if (diag304->args[1] == DIAG304_SET_WEIGHTS ||
93	    diag304->args[1] == DIAG304_SET_CAPPING)
94		if (copy_from_user(data, udata, PAGE_SIZE))
95			goto out;
96
97	cmd = *(unsigned long *) &diag304->args[0];
98	diag304->rc = hypfs_sprp_diag304(data, cmd);
99
100	if (diag304->args[1] == DIAG304_QUERY_PRP)
101		if (copy_to_user(udata, data, PAGE_SIZE)) {
102			rc = -EFAULT;
103			goto out;
104		}
105
106	rc = copy_to_user(user_area, diag304, sizeof(*diag304)) ? -EFAULT : 0;
107out:
108	kfree(diag304);
109	free_page((unsigned long) data);
110	return rc;
111}
112
113static long hypfs_sprp_ioctl(struct file *file, unsigned int cmd,
114			       unsigned long arg)
115{
116	void __user *argp;
117
118	if (!capable(CAP_SYS_ADMIN))
119		return -EACCES;
120	if (is_compat_task())
121		argp = compat_ptr(arg);
122	else
123		argp = (void __user *) arg;
124	switch (cmd) {
125	case HYPFS_DIAG304:
126		return __hypfs_sprp_ioctl(argp);
127	default: /* unknown ioctl number */
128		return -ENOTTY;
129	}
130	return 0;
131}
132
133static struct hypfs_dbfs_file hypfs_sprp_file = {
134	.name		= "diag_304",
135	.data_create	= hypfs_sprp_create,
136	.data_free	= hypfs_sprp_free,
137	.unlocked_ioctl = hypfs_sprp_ioctl,
138};
139
140void hypfs_sprp_init(void)
141{
142	if (!sclp.has_sprp)
143		return;
144	hypfs_dbfs_create_file(&hypfs_sprp_file);
145}
146
147void hypfs_sprp_exit(void)
148{
149	if (!sclp.has_sprp)
150		return;
151	hypfs_dbfs_remove_file(&hypfs_sprp_file);
152}
153