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 int sys_umap_data_fb(endpoint_t ep, vir_bytes buf, vir_bytes len, phys_bytes *phys)
  10 {
  11         int r;
  12
  13         if((r=sys_umap(ep, VM_D, buf, len, phys)) != OK) {
  14                 if(r != EINVAL)
  15                         return r;
  16                 r = sys_umap(ep, D, buf, len, phys);
  17         }
  18
  19
  20         return r;
  21 }
  22
  23
  24 void *alloc_contig(size_t len, int flags, phys_bytes *phys)
  25 {
  26         vir_bytes buf;
  27         int mmapflags = MAP_PREALLOC|MAP_CONTIG|MAP_ANON;
  28
  29         if(flags & AC_LOWER16M)
  30                 mmapflags |= MAP_LOWER16M;
  31         if(flags & AC_LOWER1M)
  32                 mmapflags |= MAP_LOWER1M;
  33         if(flags & AC_ALIGN64K)
  34                 mmapflags |= MAP_ALIGN64K;
  35
  36         /* First try to get memory with mmap. This is gauranteed
  37          * to be page-aligned, and we can tell VM it has to be
  38          * pre-allocated and contiguous.
  39          */
  40         errno = 0;
  41         buf = (vir_bytes) mmap(0, len, PROT_READ|PROT_WRITE, mmapflags, -1, 0);
  42
  43         /* If that failed, maybe we're not running in paged mode.
  44          * If that's the case, ENXIO will be returned.
  45          * Memory returned with malloc() will be preallocated and
  46          * contiguous, so fallback on that, and ask for a little extra
  47          * so we can page align it ourselves.
  48          */
  49         if(buf == (vir_bytes) MAP_FAILED) {
  50                 u32_t align = 0;
  51                 if(errno != (_SIGN ENXIO)) {
  52                         return NULL;
  53                 }
  54                 if(flags & AC_ALIGN4K)
  55                         align = 4*1024;
  56                 if(flags & AC_ALIGN64K)
  57                         align = 64*1024;
  58                 if(len + align < len)
  59                         return NULL;
  60                 len += align;
  61                 if(!(buf = (vir_bytes) malloc(len))) {
  62                         return NULL;
  63                 }
  64                 if(align)
  65                         buf += align - (buf % align);
  66         }
  67
  68         /* Get physical address, if requested. */
  69         if(phys != NULL && sys_umap_data_fb(SELF, buf, len, phys) != OK)
  70                 panic("sys_umap_data_fb failed");
  71
  72         return (void *) buf;
  73 }
  74
  75 int free_contig(void *addr, size_t len)
  76 {
  77         return munmap(addr, len);
  78 }
  79