[PATCH 6/8] binman: Provide general support for updating ELF symbols
Simon Glass
sjg at chromium.org
Thu Jan 12 00:10:17 CET 2023
The current support for updating variables in a binary is hard-coded to
work with U-Boot:
- It assumes the image starts at __image_copy_start
- It uses the existing U-Boot-specific entry types
It is useful for other projects to use these feature.
Add properties to enable writing symbols for any blob, a way of specifying
the base symbol and a way of providing the ELF filename to allow symbol
lookup to take place.
With this it is possible to update a Zephyr image, such as zephyr.bin
after it has been built.
Signed-off-by: Simon Glass <sjg at chromium.org>
---
tools/binman/binman.rst | 25 ++++++++++++++++++++++
tools/binman/elf.py | 8 +++++--
tools/binman/entry.py | 3 ++-
tools/binman/etype/blob.py | 6 ++++++
tools/binman/etype/u_boot_spl.py | 1 -
tools/binman/ftest.py | 19 +++++++++++++++++
tools/binman/test/273_blob_symbol.dts | 24 +++++++++++++++++++++
tools/binman/test/Makefile | 9 +++++++-
tools/binman/test/blob_syms.c | 20 ++++++++++++++++++
tools/binman/test/blob_syms.lds | 30 +++++++++++++++++++++++++++
10 files changed, 140 insertions(+), 5 deletions(-)
create mode 100644 tools/binman/test/273_blob_symbol.dts
create mode 100644 tools/binman/test/blob_syms.c
create mode 100644 tools/binman/test/blob_syms.lds
diff --git a/tools/binman/binman.rst b/tools/binman/binman.rst
index 97e2d4e55d5..980a1ac5bde 100644
--- a/tools/binman/binman.rst
+++ b/tools/binman/binman.rst
@@ -487,6 +487,13 @@ For x86 devices (with the end-at-4gb property) this base address is not added
since it is assumed that images are XIP and the offsets already include the
address.
+While U-Boot's symbol updating is handled automatically by the u-boot-spl
+entry type (and others), it is possible to use this feature with any blob. To
+do this, add a `write-symbols` (boolean) property to the node, set the ELF
+filename using `elf-filename` and set 'elf-base-sym' to the base symbol for the
+start of the binary image (this defaults to `__image_copy_start` which is what
+U-Boot uses). See `testBlobSymbol()` for an example.
+
.. _binman_fdt:
Access to binman entry offsets at run time (fdt)
@@ -798,6 +805,24 @@ overlap:
packed with other entries, but their contents are written over other entries
in the section. Overlapping entries must have an explicit offset and size.
+write-symbols:
+ Indicates that the blob should be updated with symbol values calculated by
+ binman. This is automatic for certain entry types, e.g. `u-boot-spl`. See
+ binman_syms_ for more information.
+
+elf-filename:
+ Sets the file name of a blob's associated ELF file. For example, if the
+ blob is `zephyr.bin` then the ELF file may be `zephyr.elf`. This allows
+ binman to locate symbols and understand the structure of the blob. See
+ binman_syms_ for more information.
+
+elf-base-sym:
+ Sets the name of the ELF symbol that points to the start of a blob. For
+ U-Boot this is `__image_copy_start` and that is the default used by binman
+ if this property is missing. For other projects, a difference symbol may be
+ needed. Add this symbol to the properties for the blob so that symbols can
+ be read correctly. See binman_syms_ for more information.
+
Examples of the above options can be found in the tests. See the
tools/binman/test directory.
diff --git a/tools/binman/elf.py b/tools/binman/elf.py
index 73f318b81d2..9ac00ed9ccf 100644
--- a/tools/binman/elf.py
+++ b/tools/binman/elf.py
@@ -210,7 +210,8 @@ def GetPackString(sym, msg):
raise ValueError('%s has size %d: only 4 and 8 are supported' %
(msg, sym.size))
-def LookupAndWriteSymbols(elf_fname, entry, section, is_elf=False):
+def LookupAndWriteSymbols(elf_fname, entry, section, is_elf=False,
+ base_sym=None):
"""Replace all symbols in an entry with their correct values
The entry contents is updated so that values for referenced symbols will be
@@ -223,7 +224,10 @@ def LookupAndWriteSymbols(elf_fname, entry, section, is_elf=False):
entry
entry: Entry to process
section: Section which can be used to lookup symbol values
+ base_sym: Base symbol marking the start of the image
"""
+ if not base_sym:
+ base_sym = '__image_copy_start'
fname = tools.get_input_filename(elf_fname)
syms = GetSymbols(fname, ['image', 'binman'])
if is_elf:
@@ -243,7 +247,7 @@ def LookupAndWriteSymbols(elf_fname, entry, section, is_elf=False):
if not syms:
tout.debug('LookupAndWriteSymbols: no syms')
return
- base = syms.get('__image_copy_start')
+ base = syms.get(base_sym)
if not base and not is_elf:
tout.debug('LookupAndWriteSymbols: no base')
return
diff --git a/tools/binman/entry.py b/tools/binman/entry.py
index 0c94665f7a8..aca08e62d3a 100644
--- a/tools/binman/entry.py
+++ b/tools/binman/entry.py
@@ -144,6 +144,7 @@ class Entry(object):
self.absent = False
self.optional = False
self.overlap = False
+ self.elf_base_sym = None
@staticmethod
def FindEntryClass(etype, expanded):
@@ -676,7 +677,7 @@ class Entry(object):
# Check if we are writing symbols into an ELF file
is_elf = self.GetDefaultFilename() == self.elf_fname
elf.LookupAndWriteSymbols(self.elf_fname, self, section.GetImage(),
- is_elf)
+ is_elf, self.elf_base_sym)
def CheckEntries(self):
"""Check that the entry offsets are correct
diff --git a/tools/binman/etype/blob.py b/tools/binman/etype/blob.py
index 70dea7158ee..c7ddcedffb8 100644
--- a/tools/binman/etype/blob.py
+++ b/tools/binman/etype/blob.py
@@ -35,6 +35,12 @@ class Entry_blob(Entry):
super().__init__(section, etype, node,
auto_write_symbols=auto_write_symbols)
self._filename = fdt_util.GetString(self._node, 'filename', self.etype)
+ self.elf_fname = fdt_util.GetString(self._node, 'elf-filename',
+ self.elf_fname)
+ self.elf_base_sym = fdt_util.GetString(self._node, 'elf-base-sym')
+ if not self.auto_write_symbols:
+ if fdt_util.GetBool(self._node, 'write-symbols'):
+ self.auto_write_symbols = True
def ObtainContents(self, fake_size=0):
self._filename = self.GetDefaultFilename()
diff --git a/tools/binman/etype/u_boot_spl.py b/tools/binman/etype/u_boot_spl.py
index be1610569fc..7f710c857db 100644
--- a/tools/binman/etype/u_boot_spl.py
+++ b/tools/binman/etype/u_boot_spl.py
@@ -34,7 +34,6 @@ class Entry_u_boot_spl(Entry_blob):
def __init__(self, section, etype, node):
super().__init__(section, etype, node, auto_write_symbols=True)
self.elf_fname = 'spl/u-boot-spl'
- self.auto_write_symbols = True
def GetDefaultFilename(self):
return 'spl/u-boot-spl.bin'
diff --git a/tools/binman/ftest.py b/tools/binman/ftest.py
index aea8a5f7589..17b0431d4f3 100644
--- a/tools/binman/ftest.py
+++ b/tools/binman/ftest.py
@@ -6262,6 +6262,25 @@ fdt fdtmap Extract the devicetree blob from the fdtmap
"Node '/binman/inset': 'fill' entry is missing properties: size",
str(exc.exception))
+ def testBlobSymbol(self):
+ """Test a blob with symbols read from an ELF file"""
+ elf_fname = self.ElfTestFile('blob_syms')
+ TestFunctional._MakeInputFile('blob_syms', tools.read_file(elf_fname))
+ TestFunctional._MakeInputFile('blob_syms.bin',
+ tools.read_file(self.ElfTestFile('blob_syms.bin')))
+
+ data = self._DoReadFile('273_blob_symbol.dts')
+
+ syms = elf.GetSymbols(elf_fname, ['binman', 'image'])
+ addr = elf.GetSymbolAddress(elf_fname, '__my_start_sym')
+ self.assertEqual(syms['_binman_sym_magic'].address, addr)
+ self.assertEqual(syms['_binman_inset_prop_offset'].address, addr + 4)
+ self.assertEqual(syms['_binman_inset_prop_size'].address, addr + 8)
+
+ sym_values = struct.pack('<LLL', elf.BINMAN_SYM_MAGIC_VALUE, 4, 8)
+ expected = sym_values
+ self.assertEqual(expected, data[:len(expected)])
+
if __name__ == "__main__":
unittest.main()
diff --git a/tools/binman/test/273_blob_symbol.dts b/tools/binman/test/273_blob_symbol.dts
new file mode 100644
index 00000000000..87b0aba2120
--- /dev/null
+++ b/tools/binman/test/273_blob_symbol.dts
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/dts-v1/;
+
+/ {
+ #address-cells = <1>;
+ #size-cells = <1>;
+
+ binman {
+ blob {
+ filename = "blob_syms.bin";
+ write-symbols;
+ elf-filename = "blob_syms";
+ elf-base-sym = "__my_start_sym";
+ };
+
+ inset {
+ type = "null";
+ offset = <4>;
+ size = <8>;
+ overlap;
+ };
+ };
+};
diff --git a/tools/binman/test/Makefile b/tools/binman/test/Makefile
index bea8567c9b4..cd66a3038be 100644
--- a/tools/binman/test/Makefile
+++ b/tools/binman/test/Makefile
@@ -30,11 +30,12 @@ LDS_BINMAN_BAD := -T $(SRC)u_boot_binman_syms_bad.lds
LDS_BINMAN_X86 := -T $(SRC)u_boot_binman_syms_x86.lds
LDS_BINMAN_EMBED := -T $(SRC)u_boot_binman_embed.lds
LDS_EFL_SECTIONS := -T $(SRC)elf_sections.lds
+LDS_BLOB := -T $(SRC)blob_syms.lds
TARGETS = u_boot_ucode_ptr u_boot_no_ucode_ptr bss_data \
u_boot_binman_syms u_boot_binman_syms.bin u_boot_binman_syms_bad \
u_boot_binman_syms_size u_boot_binman_syms_x86 embed_data \
- u_boot_binman_embed u_boot_binman_embed_sm elf_sections
+ u_boot_binman_embed u_boot_binman_embed_sm elf_sections blob_syms.bin
all: $(TARGETS)
@@ -71,6 +72,12 @@ u_boot_binman_embed: u_boot_binman_embed.c
u_boot_binman_embed_sm: CFLAGS += $(LDS_BINMAN_EMBED)
u_boot_binman_embed_sm: u_boot_binman_embed_sm.c
+blob_syms.bin: blob_syms
+ $(OBJCOPY) -O binary $< -R .note.gnu.build-id $@
+
+blob_syms: CFLAGS += $(LDS_BLOB)
+blob_syms: blob_syms.c
+
elf_sections: CFLAGS += $(LDS_EFL_SECTIONS)
elf_sections: elf_sections.c
diff --git a/tools/binman/test/blob_syms.c b/tools/binman/test/blob_syms.c
new file mode 100644
index 00000000000..d652c79aa98
--- /dev/null
+++ b/tools/binman/test/blob_syms.c
@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2017 Google, Inc
+ *
+ * Simple program to create some binman symbols. This is used by binman tests.
+ */
+
+typedef unsigned long ulong;
+
+#include <linux/kconfig.h>
+#include <binman_sym.h>
+
+DECLARE_BINMAN_MAGIC_SYM;
+
+unsigned long val1 = 123;
+unsigned long val2 = 456;
+binman_sym_declare(unsigned long, inset, offset);
+unsigned long val3 = 789;
+unsigned long val4 = 999;
+binman_sym_declare(unsigned long, inset, size);
diff --git a/tools/binman/test/blob_syms.lds b/tools/binman/test/blob_syms.lds
new file mode 100644
index 00000000000..787e38dd853
--- /dev/null
+++ b/tools/binman/test/blob_syms.lds
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (c) 2016 Google, Inc
+ */
+
+OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386")
+OUTPUT_ARCH(i386)
+ENTRY(_start)
+
+SECTIONS
+{
+ . = 0x00000010;
+ _start = .;
+
+ . = ALIGN(4);
+ .text :
+ {
+ __my_start_sym = .;
+ *(.text*)
+ }
+
+ . = ALIGN(4);
+ .binman_sym_table : {
+ __binman_sym_start = .;
+ KEEP(*(SORT(.binman_sym*)));
+ __binman_sym_end = .;
+ }
+ .interp : { *(.interp*) }
+
+}
--
2.39.0.314.g84b9a713c41-goog
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