Changeset 14febed9 in mainline for kernel/arch/mips32/src/mm/frame.c

Timestamp:

2012-12-13T21:13:08Z (13 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

a4f959b

Parents:

cf538e7

Message:

Do not damage the YAMON image in SDRAM.

• Change loader and kernel link addresses so that we do not overwrite the YAMON image in SDRAM.
• Ban the YAMON SDRAM range of physical memory from allocations.

File:

• kernel/arch/mips32/src/mm/frame.c (modified) (1 diff)

kernel/arch/mips32/src/mm/frame.c

@@ -239 +239 @@
         /* Blacklist interrupt vector frame */
         frame_mark_unavailable(0, 1);
+
+#if defined(MACHINE_lmalta) || defined(MACHINE_bmalta)
+        /* Blacklist memory regions used by YAMON.
+         *
+         * The YAMON User's Manual vaguely says the following physical addresses
+         * are taken by YAMON:
+         *
+         * 0x1000       YAMON functions
+         * 0x5000       YAMON code
+         *
+         * These addresses overlap with the beginning of the SDRAM so we need to
+         * make sure they cannot be allocated.
+         *
+         * The User's Manual unfortunately does not say where does the SDRAM
+         * portion used by YAMON end.
+         *
+         * Looking into the YAMON 02.21 sources, it looks like the first free
+         * address is computed dynamically and depends on the size of the YAMON
+         * image. From the YAMON binary, it appears to be 0xc0d50 or roughly
+         * 772 KiB for that particular version.
+         *
+         * Linux is linked to 1MiB which seems to be a safe bet and a reasonable
+         * upper bound for memory taken by YAMON. We will use it too.
+         */
+        frame_mark_unavailable(0, 1024 * 1024 / FRAME_SIZE);
+#endif
         
         /* Cleanup */