Basic VM and other minor improvements.

Not complete, probably not fully debugged or optimized.

lib/syslib/alloc_util.c

@@ -0,0 +1,69 @@
+
+#include "syslib.h"
+
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/mman.h>
+#include <minix/sysutil.h>
+
+int sys_umap_data_fb(endpoint_t ep, vir_bytes buf, vir_bytes len, phys_bytes *phys)
+{
+	int r;
+
+        if((r=sys_umap(ep, VM_D, buf, len, phys)) != OK) {
+		if(r != EINVAL)
+			return r;
+        	r = sys_umap(ep, D, buf, len, phys);
+	}
+
+
+	return r;
+}
+
+
+void *alloc_contig(size_t len, int flags, phys_bytes *phys)
+{
+	int r;
+	vir_bytes buf;
+	int mmapflags = MAP_PREALLOC|MAP_CONTIG|MAP_ANON;
+
+	if(flags & AC_LOWER16M)
+		mmapflags |= MAP_LOWER16M;
+
+	/* First try to get memory with mmap. This is gauranteed
+	 * to be page-aligned, and we can tell VM it has to be
+	 * pre-allocated and contiguous.
+	 */
+	errno = 0;
+	buf = (vir_bytes) mmap(0, len, PROT_READ|PROT_WRITE, mmapflags, -1, 0);
+
+	/* If that failed, maybe we're not running in paged mode.
+	 * If that's the case, ENXIO will be returned.
+	 * Memory returned with malloc() will be preallocated and 
+	 * contiguous, so fallback on that, and ask for a little extra
+	 * so we can page align it ourselves.
+	 */
+	if(buf == (vir_bytes) MAP_FAILED) {
+		if(errno != (_SIGN ENXIO)) {
+			return NULL;
+		}
+#define ALIGN 4096
+		if(flags & AC_ALIGN4K) {
+			if(len + ALIGN < len)
+				return NULL;
+			len += ALIGN;
+		}
+		if(!(buf = (vir_bytes) malloc(len))) {
+			return NULL;
+		}
+		if(flags & AC_ALIGN4K)
+			buf += ALIGN - (buf % ALIGN);
+	}
+
+	/* Get physical address. */
+        if(sys_umap_data_fb(SELF, buf, len, phys) != OK)
+		panic("alloc_contig.c", "sys_umap_data_fb failed", NO_NUM);
+
+	return (void *) buf;
+}
+