mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-09-16 17:53:38 +09:00
d26efc89b1
This entry holds the padding between the end of of TPL binary and the end of BSS. This region must be left empty so that the devicetree can be appended correctly and remain accessible without interfering with BSS. Signed-off-by: Simon Glass <sjg@chromium.org>
45 lines
1.7 KiB
Python
45 lines
1.7 KiB
Python
# SPDX-License-Identifier: GPL-2.0+
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# Copyright 2021 Google LLC
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# Written by Simon Glass <sjg@chromium.org>
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#
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# Entry-type module for BSS padding for tpl/u-boot-tpl.bin. This padding
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# can be added after the TPL binary to ensure that anything concatenated
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# to it will appear to TPL to be at the end of BSS rather than the start.
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#
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from binman import elf
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from binman.entry import Entry
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from binman.etype.blob import Entry_blob
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from patman import tools
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class Entry_u_boot_tpl_bss_pad(Entry_blob):
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"""U-Boot TPL binary padded with a BSS region
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Properties / Entry arguments:
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None
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This holds the padding added after the TPL binary to cover the BSS (Block
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Started by Symbol) region. This region holds the various variables used by
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TPL. It is set to 0 by TPL when it starts up. If you want to append data to
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the TPL image (such as a device tree file), you must pad out the BSS region
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to avoid the data overlapping with U-Boot variables. This entry is useful in
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that case. It automatically pads out the entry size to cover both the code,
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data and BSS.
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The contents of this entry will a certain number of zero bytes, determined
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by __bss_size
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The ELF file 'tpl/u-boot-tpl' must also be available for this to work, since
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binman uses that to look up the BSS address.
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"""
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def __init__(self, section, etype, node):
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super().__init__(section, etype, node)
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def ObtainContents(self):
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fname = tools.GetInputFilename('tpl/u-boot-tpl')
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bss_size = elf.GetSymbolAddress(fname, '__bss_size')
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if not bss_size:
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self.Raise('Expected __bss_size symbol in tpl/u-boot-tpl')
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self.SetContents(tools.GetBytes(0, bss_size))
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return True
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