kernel: vm: Support NULL `addr' for private mmap()

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 6 insertions, 5 deletions

diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
index e0644fa..26effdb 100644
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -245,11 +245,6 @@ mmap(void *addr, size_t len, int prot, int flags, int fildes, off_t off)
         goto done;
     }
 
-    if (addr == NULL) {
-        pr_error("mmap: NULL addr not supported\n");
-        return NULL;
-    }
-
     /* Only allocate new obj if needed */
     if (map_obj == NULL) {
         map_obj = dynalloc(sizeof(*map_obj));
@@ -278,6 +273,12 @@ mmap(void *addr, size_t len, int prot, int flags, int fildes, off_t off)
             return NULL;
         }
 
+        /* TODO: copy-on-write */
+        if (addr == NULL) {
+            va = pg->phys_addr;
+            addr = (void *)va;
+        }
+
         pa = pg->phys_addr;
         error = vm_map(vas, va + page_off, pa, prot, len);
         if (error < 0) {