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authorStefan Reinauer <reinauer@chromium.org>2012-12-14 11:42:57 -0800
committerRonald G. Minnich <rminnich@gmail.com>2012-12-14 22:29:17 +0100
commitf6935a006a6ffe57413877093035cdc1a020e7bd (patch)
tree3a628bc91ee5238d2eda5b738168721febec383f /payloads/libpayload/arch/x86/head.S
parent9aaf7d17bbb8140ad9091d2435bdffa0d241fb56 (diff)
libpayload: rename i386 to x86
Change-Id: Ia9170bd3d04e76dbf9321ca7ea4be23b5e468d21 Signed-off-by: Stefan Reinauer <reinauer@google.com> Reviewed-on: http://review.coreboot.org/2033 Tested-by: build bot (Jenkins) Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
Diffstat (limited to 'payloads/libpayload/arch/x86/head.S')
-rw-r--r--payloads/libpayload/arch/x86/head.S104
1 files changed, 104 insertions, 0 deletions
diff --git a/payloads/libpayload/arch/x86/head.S b/payloads/libpayload/arch/x86/head.S
new file mode 100644
index 0000000000..3dd61336f9
--- /dev/null
+++ b/payloads/libpayload/arch/x86/head.S
@@ -0,0 +1,104 @@
+/*
+ * This file is part of the libpayload project.
+ *
+ * Copyright (C) 2008 Advanced Micro Devices, Inc.
+ *
+ * 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.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * 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.
+ */
+
+ .code32
+ .global _entry, _leave
+ .text
+ .align 4
+
+/*
+ * Our entry point - assume that the CPU is in 32 bit protected mode and
+ * all segments are in a flat model. That's our operating mode, so we won't
+ * change anything.
+ */
+_entry:
+ jmp _init
+
+ .align 4
+
+#define MB_MAGIC 0x1BADB002
+#define MB_FLAGS 0x00010003
+
+mb_header:
+ .long MB_MAGIC
+ .long MB_FLAGS
+ .long -(MB_MAGIC + MB_FLAGS)
+ .long mb_header
+ .long _start
+ .long _edata
+ .long _end
+ .long _init
+
+/*
+ * This function saves off the previous stack and switches us to our
+ * own execution environment.
+ */
+_init:
+ /* No interrupts, please. */
+ cli
+
+ /* There is a bunch of stuff missing here to take arguments on the stack
+ * See http://www.coreboot.org/Payload_API and exec.S.
+ */
+ /* Store current stack pointer. */
+ movl %esp, %esi
+
+ /* Store EAX and EBX */
+ movl %eax,loader_eax
+ movl %ebx,loader_ebx
+
+ /* Clear the bss */
+ cld
+ movl $.bss, %edi
+ movl $_end, %ecx
+ subl %edi, %ecx
+ xor %ax, %ax
+ rep stosb
+
+ /* Setup new stack. */
+ movl $_stack, %ebx
+
+ movl %ebx, %esp
+
+ /* Save old stack pointer. */
+ pushl %esi
+
+ /* Let's rock. */
+ call start_main
+
+ /* %eax has the return value - pass it on unmolested */
+_leave:
+ /* Get old stack pointer. */
+ popl %ebx
+
+ /* Restore old stack. */
+ movl %ebx, %esp
+
+ /* Return to the original context. */
+ ret