arch/s390/hypfs/hypfs_sprp.c

   1 /*
   2  *    Hypervisor filesystem for Linux on s390.
   3  *    Set Partition-Resource Parameter interface.
   4  *
   5  *    Copyright IBM Corp. 2013
   6  *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
   7  */
   8
   9 #include <linux/compat.h>
  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/compat.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         if (copy_from_user(&diag304, user_area, sizeof(diag304)))
  78                 return -EFAULT;
  79         if ((diag304.args[0] >> 8) != 0 || diag304.args[1] > DIAG304_CMD_MAX)
  80                 return -EINVAL;
  81
  82         data = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
  83         if (!data)
  84                 return -ENOMEM;
  85
  86         udata = (void __user *)(unsigned long) diag304.data;
  87         if (diag304.args[1] == DIAG304_SET_WEIGHTS ||
  88             diag304.args[1] == DIAG304_SET_CAPPING)
  89                 if (copy_from_user(data, udata, PAGE_SIZE)) {
  90                         rc = -EFAULT;
  91                         goto out;
  92                 }
  93
  94         cmd = *(unsigned long *) &diag304.args[0];
  95         diag304.rc = hypfs_sprp_diag304(data, cmd);
  96
  97         if (diag304.args[1] == DIAG304_QUERY_PRP)
  98                 if (copy_to_user(udata, data, PAGE_SIZE)) {
  99                         rc = -EFAULT;
 100                         goto out;
 101                 }
 102
 103         rc = copy_to_user(user_area, &diag304, sizeof(diag304)) ? -EFAULT : 0;
 104 out:
 105         free_page((unsigned long) data);
 106         return rc;
 107 }
 108
 109 static long hypfs_sprp_ioctl(struct file *file, unsigned int cmd,
 110                                unsigned long arg)
 111 {
 112         void __user *argp;
 113
 114         if (!capable(CAP_SYS_ADMIN))
 115                 return -EACCES;
 116         if (is_compat_task())
 117                 argp = compat_ptr(arg);
 118         else
 119                 argp = (void __user *) arg;
 120         switch (cmd) {
 121         case HYPFS_DIAG304:
 122                 return __hypfs_sprp_ioctl(argp);
 123         default: /* unknown ioctl number */
 124                 return -ENOTTY;
 125         }
 126         return 0;
 127 }
 128
 129 static struct hypfs_dbfs_file hypfs_sprp_file = {
 130         .name           = "diag_304",
 131         .data_create    = hypfs_sprp_create,
 132         .data_free      = hypfs_sprp_free,
 133         .unlocked_ioctl = hypfs_sprp_ioctl,
 134 };
 135
 136 int hypfs_sprp_init(void)
 137 {
 138         if (!sclp.has_sprp)
 139                 return 0;
 140         return hypfs_dbfs_create_file(&hypfs_sprp_file);
 141 }
 142
 143 void hypfs_sprp_exit(void)
 144 {
 145         if (!sclp.has_sprp)
 146                 return;
 147         hypfs_dbfs_remove_file(&hypfs_sprp_file);
 148 }