[U-Boot] [PATCH 02/20] x86: Reorder x86's post relocation memory layout

[Simon Glass]

From: Gabe Black <gabeblack at chromium.org>

This changes the layout in decreasing addresses from:

1. Stack
2. Sections in the image
3. Heap

to

1. Sections in the image
2. Heap
3. Stack

This allows the stack to grow significantly more since it isn't constrained by
the other u-boot areas. More importantly, the generic memory wipe code assumes
that the stack is the lowest addressed area used by the main part of u-boot.
In the original layout, that means that u-boot tramples all over itself. In
the new layout, it works.

Signed-off-by: Gabe Black <gabeblack at google.com>
Signed-off-by: Simon Glass <sjg at chromium.org>
---
 arch/x86/lib/init_helpers.c |    9 ++++-----
 1 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/x86/lib/init_helpers.c b/arch/x86/lib/init_helpers.c
index 4a6d9f3..6032ee5 100644
--- a/arch/x86/lib/init_helpers.c
+++ b/arch/x86/lib/init_helpers.c
@@ -96,16 +96,15 @@ int calculate_relocation_address(void)
 	dest_addr &= ~15;
 	gd->gdt_addr = dest_addr;
 
-	/* Stack is below GDT */
-	gd->start_addr_sp = dest_addr;
-
-	/* U-Boot is below the stack */
-	dest_addr -= CONFIG_SYS_STACK_SIZE;
+	/* U-Boot is below Global Data */
 	dest_addr -= (bss_end - text_start);
 	dest_addr &= ~15;
 	gd->relocaddr = dest_addr;
 	gd->reloc_off = (dest_addr - text_start);
 
+	/* Stack is at the bottom, so it can grow down */
+	gd->start_addr_sp = dest_addr - CONFIG_SYS_MALLOC_LEN;
+
 	return 0;
 }
 
-- 
1.7.7.3