From: Ben Gras <ben@minix3.org>
Date: Wed, 19 Sep 2012 13:29:53 +0000 (+0200)
Subject: vm: change NO_MEM to a more impossible value
X-Git-Tag: v3.2.1~316
X-Git-Url: http://zhaoyanbai.com/repos/%22http:/www.isc.org/icons/style.css?a=commitdiff_plain;h=25817b0854097a6a93e8cf066c83f30d65ed6656;p=minix.git

vm: change NO_MEM to a more impossible value

fixes an assert() firing when starting X. thanks to the report by pikpik.

	. NO_MEM was 0, which is actually an existing piece
	  of physical memory. it can't be allocated because it's reserved
	  for bios data (by the kernel), but it can be mapped in (e.g.
	  by X), causing sanity check disaster.
	. NONCONTIGUOUS is also obsolete as all allocations are single-page
	  now, i.e. NONCONTIGUOUS is really the default and only mode.
---

diff --git a/servers/vm/alloc.c b/servers/vm/alloc.c
index 5d9e6e497..5dbcbaa27 100644
--- a/servers/vm/alloc.c
+++ b/servers/vm/alloc.c
@@ -376,8 +376,14 @@ struct memlist *alloc_mem_in_list(phys_bytes bytes, u32_t flags, phys_bytes know
 
 	assert(!(flags & PAF_CONTIG));
 
-	if(known != MAP_NONE)
+	if(known != MAP_NONE) {
+		if(known == NO_MEM) {
+			printf("VM: odd mem for alloc_mem_in_list: 0x%lx\n",
+				known);
+			return NULL;
+		}
 		phys_count = known;
+	}
 
 	do {
 		struct memlist *ml;
@@ -426,19 +432,6 @@ struct memlist *alloc_mem_in_list(phys_bytes bytes, u32_t flags, phys_bytes know
 		rempages--;
 	} while(rempages > 0);
 
-    {
-	struct memlist *ml;
-	for(ml = head; ml; ml = ml->next) {
-		assert(ml->phys);
-#if NONCONTIGUOUS
-		if(!(flags & PAF_CONTIG)) {
-			if(ml->next)
-				assert(ml->phys + ml->length != ml->next->phys);
-		}
-#endif
-	}
-    }
-
 	return head;
 }
 
diff --git a/servers/vm/vm.h b/servers/vm/vm.h
index 66287dc37..edf205c41 100644
--- a/servers/vm/vm.h
+++ b/servers/vm/vm.h
@@ -1,6 +1,4 @@
 
-#define NO_MEM ((phys_clicks) 0)  /* returned by alloc_mem() with mem is up */
-
 /* Memory flags to pt_allocmap() and alloc_mem(). */
 #define PAF_CLEAR	0x01	/* Clear physical memory. */
 #define PAF_CONTIG	0x02	/* Physically contiguous. */
@@ -21,7 +19,6 @@
 /* VM behaviour */
 #define MEMPROTECT	0	/* Slab objects not mapped. Access with USE() */
 #define JUNKFREE	0	/* Fill freed pages with junk */
-#define NONCONTIGUOUS	0	/* Make phys pages max. noncontiguous */
 
 /* How noisy are we supposed to be? */
 #define VERBOSE		0
@@ -51,4 +48,5 @@
 #define WMF_VERIFY		0x08	/* Check pagetable contents. */
 
 #define MAP_NONE	0xFFFFFFFE
+#define NO_MEM ((phys_clicks) MAP_NONE)  /* returned by alloc_mem() with mem is up */