lib/syslib/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         int r;
  27         vir_bytes buf;
  28         int mmapflags = MAP_PREALLOC|MAP_CONTIG|MAP_ANON;
  29
  30         if(flags & AC_LOWER16M)
  31                 mmapflags |= MAP_LOWER16M;
  32         if(flags & AC_LOWER1M)
  33                 mmapflags |= MAP_LOWER1M;
  34         if(flags & AC_ALIGN64K)
  35                 mmapflags |= MAP_ALIGN64K;
  36
  37         /* First try to get memory with mmap. This is gauranteed
  38          * to be page-aligned, and we can tell VM it has to be
  39          * pre-allocated and contiguous.
  40          */
  41         errno = 0;
  42         buf = (vir_bytes) mmap(0, len, PROT_READ|PROT_WRITE, mmapflags, -1, 0);
  43
  44         /* If that failed, maybe we're not running in paged mode.
  45          * If that's the case, ENXIO will be returned.
  46          * Memory returned with malloc() will be preallocated and
  47          * contiguous, so fallback on that, and ask for a little extra
  48          * so we can page align it ourselves.
  49          */
  50         if(buf == (vir_bytes) MAP_FAILED) {
  51                 u32_t align = 0;
  52                 if(errno != (_SIGN ENXIO)) {
  53                         return NULL;
  54                 }
  55                 if(flags & AC_ALIGN4K)
  56                         align = 4*1024;
  57                 if(flags & AC_ALIGN64K)
  58                         align = 64*1024;
  59                 if(len + align < len)
  60                         return NULL;
  61                 len += align;
  62                 if(!(buf = (vir_bytes) malloc(len))) {
  63                         return NULL;
  64                 }
  65                 if(align)
  66                         buf += align - (buf % align);
  67         }
  68
  69         /* Get physical address, if requested. */
  70         if(phys != NULL && sys_umap_data_fb(SELF, buf, len, phys) != OK)
  71                 panic("alloc_contig.c", "sys_umap_data_fb failed", NO_NUM);
  72
  73         return (void *) buf;
  74 }
  75
  76 int free_contig(void *addr, size_t len)
  77 {
  78         return munmap(addr, len);
  79 }
  80