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/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
  25 static unsigned long hypfs_sprp_diag304(void *data, unsigned long cmd)
  26 {
  27         register unsigned long _data asm("2") = (unsigned long) data;
  28         register unsigned long _rc asm("3");
  29         register unsigned long _cmd asm("4") = cmd;
  30
  31         asm volatile("diag %1,%2,0x304\n"
  32                      : "=d" (_rc) : "d" (_data), "d" (_cmd) : "memory");
  33
  34         return _rc;
  35 }
  36
  37 static void hypfs_sprp_free(const void *data)
  38 {
  39         free_page((unsigned long) data);
  40 }
  41
  42 static int hypfs_sprp_create(void **data_ptr, void **free_ptr, size_t *size)
  43 {
  44         unsigned long rc;
  45         void *data;
  46
  47         data = (void *) get_zeroed_page(GFP_KERNEL);
  48         if (!data)
  49                 return -ENOMEM;
  50         rc = hypfs_sprp_diag304(data, DIAG304_QUERY_PRP);
  51         if (rc != 1) {
  52                 *data_ptr = *free_ptr = NULL;
  53                 *size = 0;
  54                 free_page((unsigned long) data);
  55                 return -EIO;
  56         }
  57         *data_ptr = *free_ptr = data;
  58         *size = PAGE_SIZE;
  59         return 0;
  60 }
  61
  62 static int __hypfs_sprp_ioctl(void __user *user_area)
  63 {
  64         struct hypfs_diag304 diag304;
  65         unsigned long cmd;
  66         void __user *udata;
  67         void *data;
  68         int rc;
  69
  70         if (copy_from_user(&diag304, user_area, sizeof(diag304)))
  71                 return -EFAULT;
  72         if ((diag304.args[0] >> 8) != 0 || diag304.args[1] > DIAG304_CMD_MAX)
  73                 return -EINVAL;
  74
  75         data = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
  76         if (!data)
  77                 return -ENOMEM;
  78
  79         udata = (void __user *)(unsigned long) diag304.data;
  80         if (diag304.args[1] == DIAG304_SET_WEIGHTS ||
  81             diag304.args[1] == DIAG304_SET_CAPPING)
  82                 if (copy_from_user(data, udata, PAGE_SIZE)) {
  83                         rc = -EFAULT;
  84                         goto out;
  85                 }
  86
  87         cmd = *(unsigned long *) &diag304.args[0];
  88         diag304.rc = hypfs_sprp_diag304(data, cmd);
  89
  90         if (diag304.args[1] == DIAG304_QUERY_PRP)
  91                 if (copy_to_user(udata, data, PAGE_SIZE)) {
  92                         rc = -EFAULT;
  93                         goto out;
  94                 }
  95
  96         rc = copy_to_user(user_area, &diag304, sizeof(diag304)) ? -EFAULT : 0;
  97 out:
  98         free_page((unsigned long) data);
  99         return rc;
 100 }
 101
 102 static long hypfs_sprp_ioctl(struct file *file, unsigned int cmd,
 103                                unsigned long arg)
 104 {
 105         void __user *argp;
 106
 107         if (!capable(CAP_SYS_ADMIN))
 108                 return -EACCES;
 109         if (is_compat_task())
 110                 argp = compat_ptr(arg);
 111         else
 112                 argp = (void __user *) arg;
 113         switch (cmd) {
 114         case HYPFS_DIAG304:
 115                 return __hypfs_sprp_ioctl(argp);
 116         default: /* unknown ioctl number */
 117                 return -ENOTTY;
 118         }
 119         return 0;
 120 }
 121
 122 static struct hypfs_dbfs_file hypfs_sprp_file = {
 123         .name           = "diag_304",
 124         .data_create    = hypfs_sprp_create,
 125         .data_free      = hypfs_sprp_free,
 126         .unlocked_ioctl = hypfs_sprp_ioctl,
 127 };
 128
 129 int hypfs_sprp_init(void)
 130 {
 131         if (!sclp.has_sprp)
 132                 return 0;
 133         return hypfs_dbfs_create_file(&hypfs_sprp_file);
 134 }
 135
 136 void hypfs_sprp_exit(void)
 137 {
 138         if (!sclp.has_sprp)
 139                 return;
 140         hypfs_dbfs_remove_file(&hypfs_sprp_file);
 141 }