1 files changed, 103 insertions, 0 deletions
diff --git a/sys/boot/mips/beri/boot2/relocate.S b/sys/boot/mips/beri/boot2/relocate.S
new file mode 100644
index 000000000000..d704eb54c69c
--- /dev/null
+++ b/sys/boot/mips/beri/boot2/relocate.S
@@ -0,0 +1,103 @@
+/*-
+ * Copyright (c) 2013-2014 Robert N. M. Watson
+ * All rights reserved.
+ *
+ * This software was developed by SRI International and the University of
+ * Cambridge Computer Laboratory under DARPA/AFRL contract (FA8750-10-C-0237)
+ * ("CTSRD"), as part of the DARPA CRASH research programme.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+.set mips64
+.set noreorder
+.set nobopt
+.set noat
+
+/*
+ * Save arguments from the BERI firmware for use in C-land, and jump into
+ * main.  Assume that registers/stack/etc are sufficiently initialised to get
+ * going.  Notice that we use only temporaries while relocating, as we want to
+ * retain argument registers to pass in to main().
+ *
+ * Note slightly surprising structure: boot2 is linked for a specific address,
+ * but we may start running the code somewhere else (e.g., in DRAM as inserted
+ * with JTAG, or in flash).  The starting assembly is therefore PIC, but the
+ * main body of the code is not PIC.
+ */
+
+
+		.text
+		.global prerelocate_start
+		.ent prerelocate_start
+prerelocate_start:
+
+		/*
+		 * Calculate the actual run-time, pre-relocated value of
+		 * 'start', which we will use as the source address for
+		 * memcpy().  Note that although a symbol is used here, this
+		 * should generate code for a short relative branch, leaving
+		 * the previous $pc in $ra.
+		 */
+		bal	baltarget
+		nop
+baltarget:
+		dsub	$t1, $ra, 8				/* Src. */
+
+		/*
+		 * Relocate boot2 to DRAM where we can write back global
+		 * variable values; jump to it.  Assume all values are 32-bit
+		 * aligned.  Use an inline PIC version of memcpy()
+		 * pre-relocation; strong alignment assumptions.
+		 */
+		dla	$t0, __boot2_base_vaddr__		/* Dst. */
+		dla	$t2, __boot_loader_len__		/* Len. */
+
+memcpy_loop:
+		beq	$t2, 0, memcopy_done
+		nop
+		lw	$at, 0($t1)
+		sw	$at, 0($t0)
+		daddiu	$t0, 4
+		daddiu	$t1, 4
+		daddi	$t2, -4
+		b	memcpy_loop
+		nop
+
+memcopy_done:
+		/*
+		 * We can now jump into the relocated code, running from
+		 * cached DRAM rather than uncached flash.  Note that a
+		 * relative branch instruction cannot be used.
+		 */
+		dla	$at, relocated_start
+		jr	$at
+		nop
+
+relocated_start:
+		dla	$at, start
+		jr	$at
+		nop
+
+		.end prerelocate_start