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_ALIGN64K;
  20
  21         /* First try to get memory with minix_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) minix_mmap(0, len, PROT_READ|PROT_WRITE, mmapflags, -1, 0);
  27
  28         /* If that failed, maybe we're not running in paged mode.
  29          * If that's the case, ENXIO will be returned.
  30          * Memory returned with malloc() will be preallocated and
  31          * contiguous, so fallback on that, and ask for a little extra
  32          * so we can page align it ourselves.
  33          */
  34         if(buf == (vir_bytes) MAP_FAILED) {
  35                 u32_t align = 0;
  36                 if(errno != (_SIGN ENXIO)) {
  37                         return NULL;
  38                 }
  39                 if(flags & AC_ALIGN4K)
  40                         align = 4*1024;
  41                 if(flags & AC_ALIGN64K)
  42                         align = 64*1024;
  43                 if(len + align < len)
  44                         return NULL;
  45                 len += align;
  46                 if(!(buf = (vir_bytes) malloc(len))) {
  47                         return NULL;
  48                 }
  49                 if(align)
  50                         buf += align - (buf % align);
  51         }
  52
  53         /* Get physical address, if requested. */
  54         if(phys != NULL && sys_umap(SELF, VM_D, buf, len, phys) != OK)
  55                 panic("sys_umap_data_fb failed");
  56
  57         return (void *) buf;
  58 }
  59
  60 int free_contig(void *addr, size_t len)
  61 {
  62         return minix_munmap(addr, len);
  63 }
  64