New patch to review for coreboot: arch/x86: Add common assembly code for stages that run in CAR

[Andrey Petrov]

Andrey Petrov ([e-mail]) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/13861

-gerrit

commit fa86b4b59dfe44c8a15a37a2b00d9ae662681090
Author: Andrey Petrov <[e-mail]>
Date:   Sun Feb 28 22:37:15 2016 -0800

    arch/x86: Add common assembly code for stages that run in CAR
    
    This adds a few assembly lines that are generic enought to be shared
    between romstage and verstage that are ran in CAR.
    
    Change-Id: Ie7ef6a02f62627f29a109126d08c68176075bd67
    Signed-off-by: Andrey Petrov <[e-mail]>
---
 src/arch/x86/carstage_entry.S | 46 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/src/arch/x86/carstage_entry.S b/src/arch/x86/carstage_entry.S
new file mode 100644
index 0000000..4fc7283
--- /dev/null
+++ b/src/arch/x86/carstage_entry.S
@@ -0,0 +1,46 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2016 Intel Corp.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#define LHLT_DELAY	0x50000		/* I/O delay between post codes on failure */
+	/*
+	 * This code is meant to be used for stages that are ran in CAR.
+	 * The assumption is that gdt is already loaded. So in order to
+	 * continue with C code execution we needed to set stack pointer
+	 * and clear CAR_GLOBAL variables that are stage-specific.
+	 */
+
+	/* reset stack pointer to CAR stack */
+	mov	$_car_stack_end, %esp
+
+	/* clear CAR_GLOBAL area as it is not shared */
+	cld
+	xor	%eax, %eax
+	movl	$(_car_global_end), %ecx
+	movl	$(_car_global_start), %edi
+	sub	%edi, %ecx
+	rep	stosl
+
+	jmp	romstage_car_entry
+	movb	$0x69, %ah
+	jmp	.Lhlt
+
+.Lhlt:
+	xchg	%al, %ah
+#if IS_ENABLED(CONFIG_POST_IO)
+	outb	%al, $CONFIG_POST_IO_PORT
+#else
+	post_code(POST_DEAD_CODE)
+#endif
+	movl	$LHLT_DELAY, %ecx
+.Lhlt_Delay:
+	outb	%al, $0xED
+	loop	.Lhlt_Delay
+	jmp	.Lhlt