--- linux/arch/i386/kernel/setup.c.original	Mon Jul 22 21:44:45 2002
+++ linux/arch/i386/kernel/setup.c	Tue Jul 23 03:38:08 2002
@@ -808,21 +808,29 @@
 				userdef = 1;
 			} else {
 				/* If the user specifies memory size, we
-				 * limit the BIOS-provided memory map to
-				 * that size. exactmap can be used to specify
-				 * the exact map. mem=number can be used to
-				 * trim the existing memory map.
+				 * blow away any automatically generated
+				 * size
 				 */
 				unsigned long long start_at, mem_size;
  
+				if (userdef == 0) {
+					/* first time in: zap the whitelist
+					 * and reinitialize it with the
+					 * standard low-memory region.
+					 */
+					e820.nr_map = 0;
+					userdef = 1;
+					add_memory_region(0, LOWMEMSIZE(), E820_RAM);
+				}
 				mem_size = memparse(from+4, &from);
-				if (*from == '@') {
+				if (*from == '@')
 					start_at = memparse(from+1, &from);
-					add_memory_region(start_at, mem_size, E820_RAM);
-				} else {
-					limit_regions(mem_size);
+				else {
+					start_at = HIGH_MEMORY;
+					mem_size -= HIGH_MEMORY;
 					userdef=1;
 				}
+				add_memory_region(start_at, mem_size, E820_RAM);
 			}
 		}