u-boot/tools/binman/image.py
Simon Glass 1979063264 binman: Support accessing binman tables at run time
Binman construct images consisting of multiple binary files. These files
sometimes need to know (at run timme) where their peers are located. For
example, SPL may want to know where U-Boot is located in the image, so
that it can jump to U-Boot correctly on boot.

In general the positions where the binaries end up after binman has
finished packing them cannot be known at compile time. One reason for
this is that binman does not know the size of the binaries until
everything is compiled, linked and converted to binaries with objcopy.

To make this work, we add a feature to binman which checks each binary
for symbol names starting with '_binman'. These are then decoded to figure
out which entry and property they refer to. Then binman writes the value
of this symbol into the appropriate binary. With this, the symbol will
have the correct value at run time.

Macros are used to make this easier to use. As an example, this declares
a symbol that will access the 'u-boot-spl' entry to find the 'pos' value
(i.e. the position of SPL in the image):

   binman_sym_declare(unsigned long, u_boot_spl, pos);

This converts to a symbol called '_binman_u_boot_spl_prop_pos' in any
binary that includes it. Binman then updates the value in that binary,
ensuring that it can be accessed at runtime with:

   ulong u_boot_pos = binman_sym(ulong, u_boot_spl, pos);

This assigns the variable u_boot_pos to the position of SPL in the image.

Signed-off-by: Simon Glass <sjg@chromium.org>
2017-12-12 19:53:45 -07:00

305 lines
12 KiB
Python

# Copyright (c) 2016 Google, Inc
# Written by Simon Glass <sjg@chromium.org>
#
# SPDX-License-Identifier: GPL-2.0+
#
# Class for an image, the output of binman
#
from __future__ import print_function
from collections import OrderedDict
from operator import attrgetter
import re
import sys
import fdt_util
import tools
class Image:
"""A Image, representing an output from binman
An image is comprised of a collection of entries each containing binary
data. The image size must be large enough to hold all of this data.
This class implements the various operations needed for images.
Atrtributes:
_node: Node object that contains the image definition in device tree
_name: Image name
_size: Image size in bytes, or None if not known yet
_align_size: Image size alignment, or None
_pad_before: Number of bytes before the first entry starts. This
effectively changes the place where entry position 0 starts
_pad_after: Number of bytes after the last entry ends. The last
entry will finish on or before this boundary
_pad_byte: Byte to use to pad the image where there is no entry
_filename: Output filename for image
_sort: True if entries should be sorted by position, False if they
must be in-order in the device tree description
_skip_at_start: Number of bytes before the first entry starts. These
effecively adjust the starting position of entries. For example,
if _pad_before is 16, then the first entry would start at 16.
An entry with pos = 20 would in fact be written at position 4
in the image file.
_end_4gb: Indicates that the image ends at the 4GB boundary. This is
used for x86 images, which want to use positions such that a
memory address (like 0xff800000) is the first entry position.
This causes _skip_at_start to be set to the starting memory
address.
_entries: OrderedDict() of entries
"""
def __init__(self, name, node, test=False):
global entry
global Entry
import entry
from entry import Entry
self._node = node
self._name = name
self._size = None
self._align_size = None
self._pad_before = 0
self._pad_after = 0
self._pad_byte = 0
self._filename = '%s.bin' % self._name
self._sort = False
self._skip_at_start = 0
self._end_4gb = False
self._entries = OrderedDict()
if not test:
self._ReadNode()
self._ReadEntries()
def _ReadNode(self):
"""Read properties from the image node"""
self._size = fdt_util.GetInt(self._node, 'size')
self._align_size = fdt_util.GetInt(self._node, 'align-size')
if tools.NotPowerOfTwo(self._align_size):
self._Raise("Alignment size %s must be a power of two" %
self._align_size)
self._pad_before = fdt_util.GetInt(self._node, 'pad-before', 0)
self._pad_after = fdt_util.GetInt(self._node, 'pad-after', 0)
self._pad_byte = fdt_util.GetInt(self._node, 'pad-byte', 0)
filename = fdt_util.GetString(self._node, 'filename')
if filename:
self._filename = filename
self._sort = fdt_util.GetBool(self._node, 'sort-by-pos')
self._end_4gb = fdt_util.GetBool(self._node, 'end-at-4gb')
if self._end_4gb and not self._size:
self._Raise("Image size must be provided when using end-at-4gb")
if self._end_4gb:
self._skip_at_start = 0x100000000 - self._size
def CheckSize(self):
"""Check that the image contents does not exceed its size, etc."""
contents_size = 0
for entry in self._entries.values():
contents_size = max(contents_size, entry.pos + entry.size)
contents_size -= self._skip_at_start
size = self._size
if not size:
size = self._pad_before + contents_size + self._pad_after
size = tools.Align(size, self._align_size)
if self._size and contents_size > self._size:
self._Raise("contents size %#x (%d) exceeds image size %#x (%d)" %
(contents_size, contents_size, self._size, self._size))
if not self._size:
self._size = size
if self._size != tools.Align(self._size, self._align_size):
self._Raise("Size %#x (%d) does not match align-size %#x (%d)" %
(self._size, self._size, self._align_size, self._align_size))
def _Raise(self, msg):
"""Raises an error for this image
Args:
msg: Error message to use in the raise string
Raises:
ValueError()
"""
raise ValueError("Image '%s': %s" % (self._node.path, msg))
def GetPath(self):
"""Get the path of an image (in the FDT)
Returns:
Full path of the node for this image
"""
return self._node.path
def _ReadEntries(self):
for node in self._node.subnodes:
self._entries[node.name] = Entry.Create(self, node)
def FindEntryType(self, etype):
"""Find an entry type in the image
Args:
etype: Entry type to find
Returns:
entry matching that type, or None if not found
"""
for entry in self._entries.values():
if entry.etype == etype:
return entry
return None
def GetEntryContents(self):
"""Call ObtainContents() for each entry
This calls each entry's ObtainContents() a few times until they all
return True. We stop calling an entry's function once it returns
True. This allows the contents of one entry to depend on another.
After 3 rounds we give up since it's likely an error.
"""
todo = self._entries.values()
for passnum in range(3):
next_todo = []
for entry in todo:
if not entry.ObtainContents():
next_todo.append(entry)
todo = next_todo
if not todo:
break
def _SetEntryPosSize(self, name, pos, size):
"""Set the position and size of an entry
Args:
name: Entry name to update
pos: New position
size: New size
"""
entry = self._entries.get(name)
if not entry:
self._Raise("Unable to set pos/size for unknown entry '%s'" % name)
entry.SetPositionSize(self._skip_at_start + pos, size)
def GetEntryPositions(self):
"""Handle entries that want to set the position/size of other entries
This calls each entry's GetPositions() method. If it returns a list
of entries to update, it updates them.
"""
for entry in self._entries.values():
pos_dict = entry.GetPositions()
for name, info in pos_dict.iteritems():
self._SetEntryPosSize(name, *info)
def PackEntries(self):
"""Pack all entries into the image"""
pos = self._skip_at_start
for entry in self._entries.values():
pos = entry.Pack(pos)
def _SortEntries(self):
"""Sort entries by position"""
entries = sorted(self._entries.values(), key=lambda entry: entry.pos)
self._entries.clear()
for entry in entries:
self._entries[entry._node.name] = entry
def CheckEntries(self):
"""Check that entries do not overlap or extend outside the image"""
if self._sort:
self._SortEntries()
pos = 0
prev_name = 'None'
for entry in self._entries.values():
if (entry.pos < self._skip_at_start or
entry.pos >= self._skip_at_start + self._size):
entry.Raise("Position %#x (%d) is outside the image starting "
"at %#x (%d)" %
(entry.pos, entry.pos, self._skip_at_start,
self._skip_at_start))
if entry.pos < pos:
entry.Raise("Position %#x (%d) overlaps with previous entry '%s' "
"ending at %#x (%d)" %
(entry.pos, entry.pos, prev_name, pos, pos))
pos = entry.pos + entry.size
prev_name = entry.GetPath()
def ProcessEntryContents(self):
"""Call the ProcessContents() method for each entry
This is intended to adjust the contents as needed by the entry type.
"""
for entry in self._entries.values():
entry.ProcessContents()
def WriteSymbols(self):
"""Write symbol values into binary files for access at run time"""
for entry in self._entries.values():
entry.WriteSymbols(self)
def BuildImage(self):
"""Write the image to a file"""
fname = tools.GetOutputFilename(self._filename)
with open(fname, 'wb') as fd:
fd.write(chr(self._pad_byte) * self._size)
for entry in self._entries.values():
data = entry.GetData()
fd.seek(self._pad_before + entry.pos - self._skip_at_start)
fd.write(data)
def LookupSymbol(self, sym_name, optional, msg):
"""Look up a symbol in an ELF file
Looks up a symbol in an ELF file. Only entry types which come from an
ELF image can be used by this function.
At present the only entry property supported is pos.
Args:
sym_name: Symbol name in the ELF file to look up in the format
_binman_<entry>_prop_<property> where <entry> is the name of
the entry and <property> is the property to find (e.g.
_binman_u_boot_prop_pos). As a special case, you can append
_any to <entry> to have it search for any matching entry. E.g.
_binman_u_boot_any_prop_pos will match entries called u-boot,
u-boot-img and u-boot-nodtb)
optional: True if the symbol is optional. If False this function
will raise if the symbol is not found
msg: Message to display if an error occurs
Returns:
Value that should be assigned to that symbol, or None if it was
optional and not found
Raises:
ValueError if the symbol is invalid or not found, or references a
property which is not supported
"""
m = re.match(r'^_binman_(\w+)_prop_(\w+)$', sym_name)
if not m:
raise ValueError("%s: Symbol '%s' has invalid format" %
(msg, sym_name))
entry_name, prop_name = m.groups()
entry_name = entry_name.replace('_', '-')
entry = self._entries.get(entry_name)
if not entry:
if entry_name.endswith('-any'):
root = entry_name[:-4]
for name in self._entries:
if name.startswith(root):
rest = name[len(root):]
if rest in ['', '-img', '-nodtb']:
entry = self._entries[name]
if not entry:
err = ("%s: Entry '%s' not found in list (%s)" %
(msg, entry_name, ','.join(self._entries.keys())))
if optional:
print('Warning: %s' % err, file=sys.stderr)
return None
raise ValueError(err)
if prop_name == 'pos':
return entry.pos
else:
raise ValueError("%s: No such property '%s'" % (msg, prop_name))