Changeset 64f6ef04 in mainline for kernel/arch/ia32/src/mm/frame.c

Timestamp:

2010-06-27T23:54:45Z (15 years ago)

Author:

Martin Decky <martin@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

05e3cb8

Parents:

a1f60f3

Message:

amd64: create identity mapping of the first 8 GB of physical memory (instead of just 4 GB) during the bootstrap process
remove the crude on-demand identity mapping creation which could lead to livelocks (unmapping the page pointing to 0 MB physical while trying to map the page pointing to 4096 MB physical)

(currently the implementation is in no way closer to the ideal solution of ticket #3, but at least it allows to debug non-trivial cases of physical memory sizes > 4 GB during the approach to solving #3)

File:

• kernel/arch/ia32/src/mm/frame.c (modified) (2 diffs)

kernel/arch/ia32/src/mm/frame.c

@@ -47 +47 @@
 #include <print.h>
 
-#define PHYSMEM_LIMIT32  0x7c000000ull
-#define PHYSMEM_LIMIT64  0xe0000000ull
+#define PHYSMEM_LIMIT32  0x07c000000ull
+#define PHYSMEM_LIMIT64  0x200000000ull
 
 size_t hardcoded_unmapped_ktext_size = 0;
@@ -96 +96 @@
                  * or clip zones which go beyond PHYSMEM_LIMIT64.
                  *
-                 * The limit PHYSMEM_LIMIT64 (3.5 GB) is caused
-                 * by various limitations of the current kernel
-                 * memory management.
+                 * The PHYSMEM_LIMIT64 (8 GB) is the size of the
+                 * fixed 1:1 identically mapped physical memory
+                 * accessible during the bootstrap process.
+                 * This is a severe limitation of the current
+                 * kernel memory management.
                  *
                  */