From: "Daniel Krüger" <daniel.krueger@systec-electronic.com>
To: barebox@lists.infradead.org
Subject: ARM memory layout
Date: Thu, 16 Jun 2016 12:11:10 +0200 [thread overview]
Message-ID: <57627B3E.5020100@systec-electronic.com> (raw)
Hello,
during the porting of barebox to a new i.MX35 board I stumbled over some
crazy things with the memory layout. The comments in file
arch/arm/cpu/entry.c seem to be wrong or at least misleading.
We configured barebox as non-relocatable image. So I think the
configured TEXT_BASE is very important.
I use the following configuration with 128 MB RAM:
CONFIG_TEXT_BASE=0x87000000
CONFIG_STACK_SIZE=0x100000
CONFIG_MALLOC_SIZE=0xd00000
The stack is configured very large in this project, because of other reason.
I get the following memory layout:
0x87ffffff top of RAM
| free-space (see arm_mem_stack() in
| arch/arm/include/asm/barebox-arm.h)
0x87ff0000 start of 64 kB free-space (vector table)
0x87feffff top of stack
|
0x87ef0000 start of 1 MB reserved stack space
0x87eeffff
| 16 kB early translation table
0x87eec000 early TTB (translation table base)
0x87eebfff malloc end
| 13 MB malloc space
0x871ec000 malloc start
| some small free space
| barebox binary
0x87000000 TEXT_BASE
This does not comply to the comment in the above mentioned source file.
There the malloc space and the vector table are missing.
I would expect some check in the source code, when TEXT_BASE is too high
or barebox binary is too large, so they collide with malloc space or
stack. By reverse engineering the detailed memory layout above, I
discovered that in another project the TEXT_BASE falls within the malloc
space.
How does is run on other ARM boards? Are they all running with
CONFIG_RELOCATABLE=Y?
Best regards,
Daniel
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next reply other threads:[~2016-06-16 10:11 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-16 10:11 Daniel Krüger [this message]
2016-06-16 13:22 ` Sascha Hauer
2016-06-17 8:42 ` Daniel Krüger
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