xref: /openbmc/linux/arch/s390/hypfs/hypfs_sprp.c (revision 176f011b)
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 
26 static 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 
38 static 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 
44 static void hypfs_sprp_free(const void *data)
45 {
46 	free_page((unsigned long) data);
47 }
48 
49 static 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 
69 static 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;
107 out:
108 	kfree(diag304);
109 	free_page((unsigned long) data);
110 	return rc;
111 }
112 
113 static 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 
133 static 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 
140 int hypfs_sprp_init(void)
141 {
142 	if (!sclp.has_sprp)
143 		return 0;
144 	return hypfs_dbfs_create_file(&hypfs_sprp_file);
145 }
146 
147 void hypfs_sprp_exit(void)
148 {
149 	if (!sclp.has_sprp)
150 		return;
151 	hypfs_dbfs_remove_file(&hypfs_sprp_file);
152 }
153