coreboot t132: Stack init re-work

1) In order to avoid stack from overflowing during ramstage decompression,
initialize stack right at the beginning of romstage.
2) Declare different Kconfig options for stack at each stage.
3) Provide a macro that does stack seeding if required and calls appropriate
function.

BUG=None
BRANCH=None
TEST=Compiles and runs successfully on rush.

Original-Change-Id: I55d6ce59ea91affba3e86d68406921497c83fb52
Original-Signed-off-by: Furquan Shaikh <furquan@google.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/206880
Original-Tested-by: Furquan Shaikh <furquan@chromium.org>
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Original-Commit-Queue: Furquan Shaikh <furquan@chromium.org>
(cherry picked from commit 5e32d73803a2a9d222fcc4ca5f58efd3abe95d34)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: Ib833a1badb170a33cbf20d232019425b59db60cd
Reviewed-on: http://review.coreboot.org/8583
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>

6 files changed, 112 insertions, 39 deletions

diff --git a/src/soc/nvidia/tegra132/Kconfig b/src/soc/nvidia/tegra132/Kconfig
index a8b9bdc139..761685abc9 100644
--- a/src/soc/nvidia/tegra132/Kconfig
+++ b/src/soc/nvidia/tegra132/Kconfig
@@ -51,14 +51,30 @@ config RAMSTAGE_BASE
 	hex
 	default 0x80200000
 
-config STACK_TOP
+config BOOTBLOCK_STACK_TOP
 	hex
 	default 0x40020000
 
-config STACK_BOTTOM
+config BOOTBLOCK_STACK_BOTTOM
 	hex
 	default 0x4001c000
 
+config ROMSTAGE_STACK_TOP
+	hex
+	default 0x40020000
+
+config ROMSTAGE_STACK_BOTTOM
+	hex
+	default 0x4001c000
+
+config RAMSTAGE_STACK_TOP
+	hex
+	default 0x80020000
+
+config RAMSTAGE_STACK_BOTTOM
+	hex
+	default 0x8001c000
+
 config CBFS_CACHE_ADDRESS
 	hex "memory address to put CBFS cache data"
 	default 0x40006000
diff --git a/src/soc/nvidia/tegra132/Makefile.inc b/src/soc/nvidia/tegra132/Makefile.inc
index c14f1c8530..8c085a945a 100644
--- a/src/soc/nvidia/tegra132/Makefile.inc
+++ b/src/soc/nvidia/tegra132/Makefile.inc
@@ -16,6 +16,7 @@ ifeq ($(CONFIG_BOOTBLOCK_CONSOLE),y)
 bootblock-$(CONFIG_DRIVERS_UART) += uart.c
 endif
 
+romstage-y += romstage_asm.S
 romstage-y += cbfs.c
 romstage-y += cbmem.c
 romstage-y += timer.c
diff --git a/src/soc/nvidia/tegra132/bootblock_asm.S b/src/soc/nvidia/tegra132/bootblock_asm.S
index ebd64a7425..1b2fbb7709 100644
--- a/src/soc/nvidia/tegra132/bootblock_asm.S
+++ b/src/soc/nvidia/tegra132/bootblock_asm.S
@@ -31,6 +31,8 @@
 
 #include <arch/asm.h>
 
+#include "stack.S"
+
 ENTRY(_start)
 	/*
 	 * Set the cpu to System mode with IRQ and FIQ disabled. Prefetch/Data
@@ -40,40 +42,7 @@ ENTRY(_start)
 	 */
 	msr	cpsr_cxf, #0xdf
 
-	/*
-	 * Initialize the stack to a known value. This is used to check for
-	 * stack overflow later in the boot process.
-	 */
-	ldr	r0, .Stack
-	ldr	r1, .Stack_size
-	sub	r0, r0, r1
-	ldr	r1, .Stack
-	ldr	r2, =0xdeadbeef
-init_stack_loop:
-	str	r2, [r0]
-	add	r0, #4
-	cmp	r0, r1
-	bne	init_stack_loop
-
-/* Set stackpointer in internal RAM to call bootblock main() */
-call_bootblock:
-	ldr	sp, .Stack /* Set up stack pointer */
-	ldr	r0,=0x00000000
-	 /*
-	  * The current design of cpu_info places the
-	  * struct at the top of the stack. The number of
-	  * words pushed must be at least as large as that
-	  * struct.
-	  */
-	push	{r0-r2}
-	bic	sp, sp, #7 /* 8-byte alignment for ABI compliance */
-	/*
-	 * Use "bl" instead of "b" even though we do not intend to return.
-	 * "bl" gets compiled to "blx" if we're transitioning from ARM to
-	 * Thumb. However, "b" will not and GCC may attempt to create a
-	 * wrapper which is currently broken.
-	 */
-	bl	main
+	stack_init stack=.Stack size=.Stack_size seed=1 func=main
 ENDPROC(_start)
 
 /* we do it this way because it's a 32-bit constant and
@@ -82,8 +51,8 @@ ENDPROC(_start)
  */
 .align 2
 .Stack:
-	.word CONFIG_STACK_TOP
+	.word CONFIG_BOOTBLOCK_STACK_TOP
 .align 2
 /* create this size the same way we do in ramstage.ld: top-bottom */
 .Stack_size:
-	.word CONFIG_STACK_TOP - CONFIG_STACK_BOTTOM
+	.word CONFIG_BOOTBLOCK_STACK_TOP - CONFIG_BOOTBLOCK_STACK_BOTTOM
diff --git a/src/soc/nvidia/tegra132/romstage.c b/src/soc/nvidia/tegra132/romstage.c
index 3bc2231131..6d51403d04 100644
--- a/src/soc/nvidia/tegra132/romstage.c
+++ b/src/soc/nvidia/tegra132/romstage.c
@@ -26,7 +26,8 @@
 #include "sdram.h"
 #include "ccplex.h"
 
-void main(void)
+void romstage(void);
+void romstage(void)
 {
 	void *entry;
 
diff --git a/src/soc/nvidia/tegra132/romstage_asm.S b/src/soc/nvidia/tegra132/romstage_asm.S
new file mode 100644
index 0000000000..ac3c93ebc1
--- /dev/null
+++ b/src/soc/nvidia/tegra132/romstage_asm.S
@@ -0,0 +1,39 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2014 Google Inc.
+ *
+ * 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; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <arch/asm.h>
+#include "stack.S"
+
+        .section ".text", "ax", %progbits
+
+ENTRY(main)
+	stack_init stack=.Stack size=.Stack_size seed=0 func=romstage
+ENDPROC(main)
+
+/* we do it this way because it's a 32-bit constant and
+ * in some cases too far away to be loaded as just an offset
+ * from IP
+ */
+.align 2
+.Stack:
+	.word CONFIG_ROMSTAGE_STACK_TOP
+.align 2
+.Stack_size:
+	.word CONFIG_ROMSTAGE_STACK_TOP - CONFIG_ROMSTAGE_STACK_BOTTOM
+
diff --git a/src/soc/nvidia/tegra132/stack.S b/src/soc/nvidia/tegra132/stack.S
new file mode 100644
index 0000000000..6d3cd4e446
--- /dev/null
+++ b/src/soc/nvidia/tegra132/stack.S
@@ -0,0 +1,47 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2014 Google Inc.
+ *
+ * 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; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/* Macro to initialize stack, perform seeding if required and finally call the
+ * function provided
+ * @stack : Stack address
+ * @size  : Stack size
+ * @seed  : Stack seeding required (1=yes/otherwise=no)
+ * @func  : Function to call after initializing stack
+ */
+.macro stack_init stack, size, seed, func
+        /* Check if stack seeding is required */
+	mov	r0, #\seed
+	cmp     r0, #1
+	bne     call_func
+	/* Stack seeding */
+	ldr     r0, \stack
+	ldr	r1, \size
+	sub	r0, r0, r1
+	ldr	r1, \stack
+	ldr	r2, =0xdeadbeef
+init_stack_loop:
+	str	r2, [r0]
+	add	r0, #4
+	cmp	r0, r1
+	bne	init_stack_loop
+
+call_func:
+	ldr	sp, \stack /* Set up stack pointer */
+	bl	\func
+.endm