hypfs_sprp.c

  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/errno.h>
 11#include <linux/gfp.h>
 12#include <linux/string.h>
 13#include <linux/types.h>
 14#include <linux/uaccess.h>
 15#include <asm/diag.h>
 16#include <asm/sclp.h>
 17#include "hypfs.h"
 18
 19#define DIAG304_SET_WEIGHTS	0
 20#define DIAG304_QUERY_PRP	1
 21#define DIAG304_SET_CAPPING	2
 22
 23#define DIAG304_CMD_MAX		2
 24
 25static inline unsigned long __hypfs_sprp_diag304(void *data, unsigned long cmd)
 26{
 27	union register_pair r1 = { .even = virt_to_phys(data), };
 28
 29	asm volatile("diag %[r1],%[r3],0x304"
 30		     : [r1] "+&d" (r1.pair)
 31		     : [r3] "d" (cmd)
 32		     : "memory");
 33	return r1.odd;
 34}
 35
 36static unsigned long hypfs_sprp_diag304(void *data, unsigned long cmd)
 37{
 38	diag_stat_inc(DIAG_STAT_X304);
 39	return __hypfs_sprp_diag304(data, cmd);
 40}
 41
 42static void hypfs_sprp_free(const void *data)
 43{
 44	free_page((unsigned long) data);
 45}
 46
 47static int hypfs_sprp_create(void **data_ptr, void **free_ptr, size_t *size)
 48{
 49	unsigned long rc;
 50	void *data;
 51
 52	data = (void *) get_zeroed_page(GFP_KERNEL);
 53	if (!data)
 54		return -ENOMEM;
 55	rc = hypfs_sprp_diag304(data, DIAG304_QUERY_PRP);
 56	if (rc != 1) {
 57		*data_ptr = *free_ptr = NULL;
 58		*size = 0;
 59		free_page((unsigned long) data);
 60		return -EIO;
 61	}
 62	*data_ptr = *free_ptr = data;
 63	*size = PAGE_SIZE;
 64	return 0;
 65}
 66
 67static int __hypfs_sprp_ioctl(void __user *user_area)
 68{
 69	struct hypfs_diag304 *diag304;
 70	unsigned long cmd;
 71	void __user *udata;
 72	void *data;
 73	int rc;
 74
 75	rc = -ENOMEM;
 76	data = (void *)get_zeroed_page(GFP_KERNEL);
 77	diag304 = kzalloc(sizeof(*diag304), GFP_KERNEL);
 78	if (!data || !diag304)
 79		goto out;
 80
 81	rc = -EFAULT;
 82	if (copy_from_user(diag304, user_area, sizeof(*diag304)))
 83		goto out;
 84	rc = -EINVAL;
 85	if ((diag304->args[0] >> 8) != 0 || diag304->args[1] > DIAG304_CMD_MAX)
 86		goto out;
 87
 88	rc = -EFAULT;
 89	udata = (void __user *)(unsigned long) diag304->data;
 90	if (diag304->args[1] == DIAG304_SET_WEIGHTS ||
 91	    diag304->args[1] == DIAG304_SET_CAPPING)
 92		if (copy_from_user(data, udata, PAGE_SIZE))
 93			goto out;
 94
 95	cmd = *(unsigned long *) &diag304->args[0];
 96	diag304->rc = hypfs_sprp_diag304(data, cmd);
 97
 98	if (diag304->args[1] == DIAG304_QUERY_PRP)
 99		if (copy_to_user(udata, data, PAGE_SIZE)) {
100			rc = -EFAULT;
101			goto out;
102		}
103
104	rc = copy_to_user(user_area, diag304, sizeof(*diag304)) ? -EFAULT : 0;
105out:
106	kfree(diag304);
107	free_page((unsigned long) data);
108	return rc;
109}
110
111static long hypfs_sprp_ioctl(struct file *file, unsigned int cmd,
112			       unsigned long arg)
113{
114	void __user *argp;
115
116	if (!capable(CAP_SYS_ADMIN))
117		return -EACCES;
118	argp = (void __user *)arg;
119	switch (cmd) {
120	case HYPFS_DIAG304:
121		return __hypfs_sprp_ioctl(argp);
122	default: /* unknown ioctl number */
123		return -ENOTTY;
124	}
125	return 0;
126}
127
128static struct hypfs_dbfs_file hypfs_sprp_file = {
129	.name		= "diag_304",
130	.data_create	= hypfs_sprp_create,
131	.data_free	= hypfs_sprp_free,
132	.unlocked_ioctl = hypfs_sprp_ioctl,
133};
134
135void hypfs_sprp_init(void)
136{
137	if (!sclp.has_sprp)
138		return;
139	hypfs_dbfs_create_file(&hypfs_sprp_file);
140}
141
142void hypfs_sprp_exit(void)
143{
144	if (!sclp.has_sprp)
145		return;
146	hypfs_dbfs_remove_file(&hypfs_sprp_file);
147}