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	union register_pair r1 = { .even = virt_to_phys(data), };
29
30	asm volatile("diag %[r1],%[r3],0x304\n"
31		     : [r1] "+&d" (r1.pair)
32		     : [r3] "d" (cmd)
33		     : "memory");
34	return r1.odd;
35}
36
37static unsigned long hypfs_sprp_diag304(void *data, unsigned long cmd)
38{
39	diag_stat_inc(DIAG_STAT_X304);
40	return __hypfs_sprp_diag304(data, cmd);
41}
42
43static void hypfs_sprp_free(const void *data)
44{
45	free_page((unsigned long) data);
46}
47
48static int hypfs_sprp_create(void **data_ptr, void **free_ptr, size_t *size)
49{
50	unsigned long rc;
51	void *data;
52
53	data = (void *) get_zeroed_page(GFP_KERNEL);
54	if (!data)
55		return -ENOMEM;
56	rc = hypfs_sprp_diag304(data, DIAG304_QUERY_PRP);
57	if (rc != 1) {
58		*data_ptr = *free_ptr = NULL;
59		*size = 0;
60		free_page((unsigned long) data);
61		return -EIO;
62	}
63	*data_ptr = *free_ptr = data;
64	*size = PAGE_SIZE;
65	return 0;
66}
67
68static int __hypfs_sprp_ioctl(void __user *user_area)
69{
70	struct hypfs_diag304 *diag304;
71	unsigned long cmd;
72	void __user *udata;
73	void *data;
74	int rc;
75
76	rc = -ENOMEM;
77	data = (void *)get_zeroed_page(GFP_KERNEL);
78	diag304 = kzalloc(sizeof(*diag304), GFP_KERNEL);
79	if (!data || !diag304)
80		goto out;
81
82	rc = -EFAULT;
83	if (copy_from_user(diag304, user_area, sizeof(*diag304)))
84		goto out;
85	rc = -EINVAL;
86	if ((diag304->args[0] >> 8) != 0 || diag304->args[1] > DIAG304_CMD_MAX)
87		goto out;
88
89	rc = -EFAULT;
90	udata = (void __user *)(unsigned long) diag304->data;
91	if (diag304->args[1] == DIAG304_SET_WEIGHTS ||
92	    diag304->args[1] == DIAG304_SET_CAPPING)
93		if (copy_from_user(data, udata, PAGE_SIZE))
94			goto out;
95
96	cmd = *(unsigned long *) &diag304->args[0];
97	diag304->rc = hypfs_sprp_diag304(data, cmd);
98
99	if (diag304->args[1] == DIAG304_QUERY_PRP)
100		if (copy_to_user(udata, data, PAGE_SIZE)) {
101			rc = -EFAULT;
102			goto out;
103		}
104
105	rc = copy_to_user(user_area, diag304, sizeof(*diag304)) ? -EFAULT : 0;
106out:
107	kfree(diag304);
108	free_page((unsigned long) data);
109	return rc;
110}
111
112static long hypfs_sprp_ioctl(struct file *file, unsigned int cmd,
113			       unsigned long arg)
114{
115	void __user *argp;
116
117	if (!capable(CAP_SYS_ADMIN))
118		return -EACCES;
119	if (is_compat_task())
120		argp = compat_ptr(arg);
121	else
122		argp = (void __user *) arg;
123	switch (cmd) {
124	case HYPFS_DIAG304:
125		return __hypfs_sprp_ioctl(argp);
126	default: /* unknown ioctl number */
127		return -ENOTTY;
128	}
129	return 0;
130}
131
132static struct hypfs_dbfs_file hypfs_sprp_file = {
133	.name		= "diag_304",
134	.data_create	= hypfs_sprp_create,
135	.data_free	= hypfs_sprp_free,
136	.unlocked_ioctl = hypfs_sprp_ioctl,
137};
138
139void hypfs_sprp_init(void)
140{
141	if (!sclp.has_sprp)
142		return;
143	hypfs_dbfs_create_file(&hypfs_sprp_file);
144}
145
146void hypfs_sprp_exit(void)
147{
148	if (!sclp.has_sprp)
149		return;
150	hypfs_dbfs_remove_file(&hypfs_sprp_file);
151}
152