From b90f77b95cd1509754b8038db10dde36c679c052 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Mon, 22 Apr 2024 13:43:54 -0400
Subject: kernel: vm_map: Fix anon map bug

We should allocate physical memory before we map so the address returned
isn't 0. We should also set the virtual memory object for the mapping.

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 sys/vm/vm_map.c | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

(limited to 'sys/vm')

diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
index 7e67ebd..2d7638e 100644
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -327,16 +327,6 @@ mmap(void *addr, size_t len, int prot, int flags, int fildes, off_t off)
     if ((prot & ~PROT_MASK) != 0)
         return MAP_FAILED;
 
-    /*
-     * Handle address being NULL.
-     *
-     * FIXME: XXX: We currently identity map physmem which
-     *             is probably not ideal.
-     */
-    if (addr == NULL) {
-        addr = (void *)physmem;
-    }
-
     /*
      * Now we check what type of map request
      * this is.
@@ -346,6 +336,13 @@ mmap(void *addr, size_t len, int prot, int flags, int fildes, off_t off)
         if (vm_obj_init(&vmobj, NULL) != 0)
             return 0;
 
+        /*
+         * If 'addr' is NULL, we'll just allocate physical
+         * memory right away.
+         */
+        if (addr == NULL)
+            physmem = vm_alloc_pageframe(len / GRANULE);
+
         /*
          * Enable demand paging for this object if
          * `addr` is not NULL.
@@ -356,8 +353,14 @@ mmap(void *addr, size_t len, int prot, int flags, int fildes, off_t off)
 
             mapping->vmobj = vmobj;
             mapping->physmem_base = 0;
-        } else {
-            physmem = vm_map(addr, 0, prot, len);
+        } else if (physmem != 0) {
+            vm_map((void *)physmem, physmem, prot, len);
+            addr = (void *)physmem;
+
+            vmobj->is_anon = 1;
+            vmobj->demand = 0;
+            mapping->vmobj = vmobj;
+            mapping->physmem_base = physmem;
         }
 
         /* Did this work? */
-- 
cgit v1.2.3