minix/minix/lib/libsys/alloc_util.c
Cristiano Giuffrida 5c8eb53d49 libsys: mark regions allocated for DMA as special
This ensures that they will not be relocated.

Edited by David van Moolenbroek.

Change-Id: Ic2a97bc65b94dfcf364c06577aa340a9a5299e74
2015-09-16 15:31:55 +00:00

44 lines
953 B
C

#include "syslib.h"
#include <stdlib.h>
#include <errno.h>
#include <sys/mman.h>
#include <minix/sysutil.h>
void *alloc_contig(size_t len, int flags, phys_bytes *phys)
{
void* buf;
int mmapflags = MAP_PREALLOC|MAP_CONTIG|MAP_ANON;
if(flags & AC_LOWER16M)
mmapflags |= MAP_LOWER16M;
if(flags & AC_LOWER1M)
mmapflags |= MAP_LOWER1M;
if(flags & AC_ALIGN64K)
mmapflags |= MAP_ALIGNMENT_64KB;
/* First try to get memory with mmap. This is guaranteed
* to be page-aligned, and we can tell VM it has to be
* pre-allocated and contiguous.
*/
errno = 0;
buf = sef_llvm_ac_mmap(0, len, PROT_READ|PROT_WRITE, mmapflags, -1, 0);
if(buf == MAP_FAILED) {
return NULL;
}
/* Get physical address, if requested. */
if(phys != NULL && sys_umap(SELF, VM_D, (vir_bytes)buf, len,
phys) != OK)
panic("sys_umap_data_fb failed");
return buf;
}
int free_contig(void *addr, size_t len)
{
return sef_llvm_ac_munmap(addr, len);
}