minix/kernel/arch/i386/do_sdevio.c

   1 /* The kernel call implemented in this file:
   2  *   m_type:    SYS_SDEVIO
   3  *
   4  * The parameters for this kernel call are:
   5  *    m_lsys_krn_sys_sdevio.request     (request input or output)
   6  *    m_lsys_krn_sys_sdevio.port        (port to read/ write)
   7  *    m_lsys_krn_sys_sdevio.vec_addr    (virtual address of buffer, or grant ID)
   8  *    m_lsys_krn_sys_sdevio.vec_size    (number of elements)
   9  *    m_lsys_krn_sys_sdevio.vec_endpt   (process where buffer is)
  10  *    m_lsys_krn_sys_sdevio.offset      (offset into the grant)
  11  */
  12
  13 #include "kernel/system.h"
  14 #include <minix/devio.h>
  15 #include <minix/endpoint.h>
  16
  17 #include "arch_proto.h"
  18
  19 #if USE_SDEVIO
  20
  21 /*===========================================================================*
  22  *                              do_sdevio                                    *
  23  *===========================================================================*/
  24 int do_sdevio(struct proc * caller, message *m_ptr)
  25 {
  26   vir_bytes newoffset;
  27   endpoint_t newep;
  28   int proc_nr;
  29   endpoint_t proc_nr_e = m_ptr->m_lsys_krn_sys_sdevio.vec_endpt;
  30   vir_bytes count = m_ptr->m_lsys_krn_sys_sdevio.vec_size;
  31   long port = m_ptr->m_lsys_krn_sys_sdevio.port;
  32   phys_bytes vir_buf;
  33   int i, r, req_type, req_dir, size, nr_io_range;
  34   struct priv *privp;
  35   struct io_range *iorp;
  36   struct proc *destproc;
  37   int retval;
  38
  39   /* Allow safe copies and accesses to SELF */
  40   if ((m_ptr->m_lsys_krn_sys_sdevio.request & _DIO_SAFEMASK) != _DIO_SAFE &&
  41         proc_nr_e != SELF)
  42   {
  43         static int first= 1;
  44         if (first)
  45         {
  46                 first= 0;
  47                 printf("do_sdevio: for %d, req %d\n",
  48                         m_ptr->m_source, m_ptr->m_lsys_krn_sys_sdevio.request);
  49         }
  50   }
  51
  52   /* Check if process endpoint is OK.
  53    * A driver may directly provide a pointer to a buffer at the user-process
  54    * that initiated the device I/O. Kernel processes, of course, are denied.
  55    */
  56   if (proc_nr_e == SELF)
  57         okendpt(caller->p_endpoint, &proc_nr);
  58   else
  59         if(!isokendpt(proc_nr_e, &proc_nr))
  60                 return(EINVAL);
  61   if (iskerneln(proc_nr)) return(EPERM);
  62
  63   /* Extract direction (in or out) and type (size). */
  64   req_dir = m_ptr->m_lsys_krn_sys_sdevio.request & _DIO_DIRMASK;
  65   req_type = m_ptr->m_lsys_krn_sys_sdevio.request & _DIO_TYPEMASK;
  66
  67   /* Check for 'safe' variants. */
  68   if((m_ptr->m_lsys_krn_sys_sdevio.request & _DIO_SAFEMASK) == _DIO_SAFE) {
  69      /* Map grant address to physical address. */
  70      if((r=verify_grant(proc_nr_e, caller->p_endpoint,
  71                 m_ptr->m_lsys_krn_sys_sdevio.vec_addr, count,
  72                 req_dir == _DIO_INPUT ? CPF_WRITE : CPF_READ,
  73                 m_ptr->m_lsys_krn_sys_sdevio.offset, &newoffset, &newep,
  74                 NULL)) != OK) {
  75         if(r == ENOTREADY) return r;
  76         printf("do_sdevio: verify_grant failed\n");
  77         return EPERM;
  78     }
  79         if(!isokendpt(newep, &proc_nr))
  80                 return(EINVAL);
  81      destproc = proc_addr(proc_nr);
  82      vir_buf = newoffset;
  83   } else {
  84      if(proc_nr != _ENDPOINT_P(caller->p_endpoint))
  85      {
  86         printf("do_sdevio: unsafe sdevio by %d in %d denied\n",
  87                 caller->p_endpoint, proc_nr_e);
  88         return EPERM;
  89      }
  90      /* Get and check physical address. */
  91      vir_buf = m_ptr->m_lsys_krn_sys_sdevio.vec_addr;
  92      destproc = proc_addr(proc_nr);
  93   }
  94      /* current process must be target for phys_* to be OK */
  95
  96   switch_address_space(destproc);
  97
  98   switch (req_type)
  99   {
 100         case _DIO_BYTE: size= 1; break;
 101         case _DIO_WORD: size= 2; break;
 102         case _DIO_LONG: size= 4; break;
 103         default: size= 4; break;        /* Be conservative */
 104   }
 105
 106   privp= priv(caller);
 107   if (privp && privp->s_flags & CHECK_IO_PORT)
 108   {
 109         port= m_ptr->m_lsys_krn_sys_sdevio.port;
 110         nr_io_range= privp->s_nr_io_range;
 111         for (i= 0, iorp= privp->s_io_tab; i<nr_io_range; i++, iorp++)
 112         {
 113                 if (port >= iorp->ior_base && port+size-1 <= iorp->ior_limit)
 114                         break;
 115         }
 116         if (i >= nr_io_range)
 117         {
 118                 printf(
 119                 "do_sdevio: I/O port check failed for proc %d, port 0x%x\n",
 120                         m_ptr->m_source, port);
 121                 retval = EPERM;
 122                 goto return_error;
 123         }
 124   }
 125
 126   if (port & (size-1))
 127   {
 128         printf("do_devio: unaligned port 0x%x (size %d)\n", port, size);
 129         retval = EPERM;
 130         goto return_error;
 131   }
 132
 133   /* Perform device I/O for bytes and words. Longs are not supported. */
 134   if (req_dir == _DIO_INPUT) {
 135       switch (req_type) {
 136       case _DIO_BYTE: phys_insb(port, vir_buf, count); break;
 137       case _DIO_WORD: phys_insw(port, vir_buf, count); break;
 138       default:
 139                 retval = EINVAL;
 140                 goto return_error;
 141       }
 142   } else if (req_dir == _DIO_OUTPUT) {
 143       switch (req_type) {
 144       case _DIO_BYTE: phys_outsb(port, vir_buf, count); break;
 145       case _DIO_WORD: phys_outsw(port, vir_buf, count); break;
 146       default:
 147                 retval = EINVAL;
 148                 goto return_error;
 149       }
 150   }
 151   else {
 152           retval = EINVAL;
 153           goto return_error;
 154   }
 155   retval = OK;
 156
 157 return_error:
 158   /* switch back to the address of the process which made the call */
 159   switch_address_space(caller);
 160   return retval;
 161 }
 162
 163 #endif /* USE_SDEVIO */