lib/libsys/alloc_util.c

   1
   2 #include "syslib.h"
   3
   4 #include <stdlib.h>
   5 #include <errno.h>
   6 #include <sys/mman.h>
   7 #include <minix/sysutil.h>
   8
   9 void *alloc_contig(size_t len, int flags, phys_bytes *phys)
  10 {
  11         vir_bytes buf;
  12         int mmapflags = MAP_PREALLOC|MAP_CONTIG|MAP_ANON;
  13
  14         if(flags & AC_LOWER16M)
  15                 mmapflags |= MAP_LOWER16M;
  16         if(flags & AC_LOWER1M)
  17                 mmapflags |= MAP_LOWER1M;
  18         if(flags & AC_ALIGN64K)
  19                 mmapflags |= MAP_ALIGNMENT_64KB;
  20
  21         /* First try to get memory with mmap. This is guaranteed
  22          * to be page-aligned, and we can tell VM it has to be
  23          * pre-allocated and contiguous.
  24          */
  25         errno = 0;
  26         buf = (vir_bytes) mmap(0, len, PROT_READ|PROT_WRITE, mmapflags, -1, 0);
  27
  28         if(buf == (vir_bytes) MAP_FAILED) {
  29                 return NULL;
  30         }
  31
  32         /* Get physical address, if requested. */
  33         if(phys != NULL && sys_umap(SELF, VM_D, buf, len, phys) != OK)
  34                 panic("sys_umap_data_fb failed");
  35
  36         return (void *) buf;
  37 }
  38
  39 int free_contig(void *addr, size_t len)
  40 {
  41         return munmap(addr, len);
  42 }
  43