binman: Provide general support for updating ELF symbols

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@chromium.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/tools/binman/ftest.py b/tools/binman/ftest.py
index aea8a5f758..17b0431d4f 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()