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 = (unsigned long)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 | GFP_DMA);
 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}