minix/kernel/system/do_umap.c

   1 /* The kernel call implemented in this file:
   2  *   m_type:    SYS_UMAP
   3  *
   4  * The parameters for this kernel call are:
   5  *   m_lsys_krn_sys_umap.src_endpt      (process number)
   6  *   m_lsys_krn_sys_umap.segment        (segment where address is: T, D, or S)
   7  *   m_lsys_krn_sys_umap.src_addr       (virtual address)
   8  *   m_krn_lsys_sys_umap.dst_addr       (returns physical address)
   9  *   m_lsys_krn_sys_umap.nr_bytes       (size of datastructure)
  10  */
  11
  12 #include "kernel/system.h"
  13
  14 #include <minix/endpoint.h>
  15
  16 #if USE_UMAP
  17
  18 #if ! USE_UMAP_REMOTE
  19 #undef do_umap_remote
  20 #endif
  21
  22 /*==========================================================================*
  23  *                              do_umap                                     *
  24  *==========================================================================*/
  25 int do_umap(struct proc * caller, message * m_ptr)
  26 {
  27   int seg_index = m_ptr->m_lsys_krn_sys_umap.segment & SEGMENT_INDEX;
  28   int endpt = m_ptr->m_lsys_krn_sys_umap.src_endpt;
  29
  30   /* This call is a subset of umap_remote, it allows mapping virtual addresses
  31    * in the caller's address space and grants where the caller is specified as
  32    * grantee; after the security check we simply invoke do_umap_remote
  33    */
  34   if (seg_index != MEM_GRANT && endpt != SELF) return EPERM;
  35   m_ptr->m_lsys_krn_sys_umap.dst_endpt = SELF;
  36   return do_umap_remote(caller, m_ptr);
  37 }
  38
  39 #endif /* USE_UMAP */