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

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Submitter Simon Glass
Date Nov. 3, 2012, 9:41 p.m.
Message ID <1351978902-23719-3-git-send-email-sjg@chromium.org>
Download mbox | patch
Permalink /patch/196935/
State Accepted, archived
Delegated to: Simon Glass
Headers show

Comments

Simon Glass - Nov. 3, 2012, 9:41 p.m.
From: Gabe Black <gabeblack@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@google.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
---
 arch/x86/lib/init_helpers.c |    9 ++++-----
 1 files changed, 4 insertions(+), 5 deletions(-)

Patch

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;
 }