arch/s390/hypfs/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/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/compat.h>
  17 #include <asm/diag.h>
  18 #include <asm/sclp.h>
  19 #include "hypfs.h"
  20
  21 #define DIAG304_SET_WEIGHTS     0
  22 #define DIAG304_QUERY_PRP       1
  23 #define DIAG304_SET_CAPPING     2
  24
  25 #define DIAG304_CMD_MAX         2
  26
  27 static inline unsigned long __hypfs_sprp_diag304(void *data, unsigned long cmd)
  28 {
  29         register unsigned long _data asm("2") = (unsigned long) data;
  30         register unsigned long _rc asm("3");
  31         register unsigned long _cmd asm("4") = cmd;
  32
  33         asm volatile("diag %1,%2,0x304\n"
  34                      : "=d" (_rc) : "d" (_data), "d" (_cmd) : "memory");
  35
  36         return _rc;
  37 }
  38
  39 static unsigned long hypfs_sprp_diag304(void *data, unsigned long cmd)
  40 {
  41         diag_stat_inc(DIAG_STAT_X304);
  42         return __hypfs_sprp_diag304(data, cmd);
  43 }
  44
  45 static void hypfs_sprp_free(const void *data)
  46 {
  47         free_page((unsigned long) data);
  48 }
  49
  50 static int hypfs_sprp_create(void **data_ptr, void **free_ptr, size_t *size)
  51 {
  52         unsigned long rc;
  53         void *data;
  54
  55         data = (void *) get_zeroed_page(GFP_KERNEL);
  56         if (!data)
  57                 return -ENOMEM;
  58         rc = hypfs_sprp_diag304(data, DIAG304_QUERY_PRP);
  59         if (rc != 1) {
  60                 *data_ptr = *free_ptr = NULL;
  61                 *size = 0;
  62                 free_page((unsigned long) data);
  63                 return -EIO;
  64         }
  65         *data_ptr = *free_ptr = data;
  66         *size = PAGE_SIZE;
  67         return 0;
  68 }
  69
  70 static int __hypfs_sprp_ioctl(void __user *user_area)
  71 {
  72         struct hypfs_diag304 diag304;
  73         unsigned long cmd;
  74         void __user *udata;
  75         void *data;
  76         int rc;
  77
  78         if (copy_from_user(&diag304, user_area, sizeof(diag304)))
  79                 return -EFAULT;
  80         if ((diag304.args[0] >> 8) != 0 || diag304.args[1] > DIAG304_CMD_MAX)
  81                 return -EINVAL;
  82
  83         data = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
  84         if (!data)
  85                 return -ENOMEM;
  86
  87         udata = (void __user *)(unsigned long) diag304.data;
  88         if (diag304.args[1] == DIAG304_SET_WEIGHTS ||
  89             diag304.args[1] == DIAG304_SET_CAPPING)
  90                 if (copy_from_user(data, udata, PAGE_SIZE)) {
  91                         rc = -EFAULT;
  92                         goto out;
  93                 }
  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;
 105 out:
 106         free_page((unsigned long) data);
 107         return rc;
 108 }
 109
 110 static long hypfs_sprp_ioctl(struct file *file, unsigned int cmd,
 111                                unsigned long arg)
 112 {
 113         void __user *argp;
 114
 115         if (!capable(CAP_SYS_ADMIN))
 116                 return -EACCES;
 117         if (is_compat_task())
 118                 argp = compat_ptr(arg);
 119         else
 120                 argp = (void __user *) arg;
 121         switch (cmd) {
 122         case HYPFS_DIAG304:
 123                 return __hypfs_sprp_ioctl(argp);
 124         default: /* unknown ioctl number */
 125                 return -ENOTTY;
 126         }
 127         return 0;
 128 }
 129
 130 static struct hypfs_dbfs_file hypfs_sprp_file = {
 131         .name           = "diag_304",
 132         .data_create    = hypfs_sprp_create,
 133         .data_free      = hypfs_sprp_free,
 134         .unlocked_ioctl = hypfs_sprp_ioctl,
 135 };
 136
 137 int hypfs_sprp_init(void)
 138 {
 139         if (!sclp.has_sprp)
 140                 return 0;
 141         return hypfs_dbfs_create_file(&hypfs_sprp_file);
 142 }
 143
 144 void hypfs_sprp_exit(void)
 145 {
 146         if (!sclp.has_sprp)
 147                 return;
 148         hypfs_dbfs_remove_file(&hypfs_sprp_file);
 149 }