| #!/usr/bin/env python3 |
| # |
| # Copyright (c) 2017 Intel Corporation |
| # Copyright (c) 2020 Nordic Semiconductor NA |
| # |
| # SPDX-License-Identifier: Apache-2.0 |
| """Translate generic handles into ones optimized for the application. |
| |
| Immutable device data includes information about dependencies, |
| e.g. that a particular sensor is controlled through a specific I2C bus |
| and that it signals event on a pin on a specific GPIO controller. |
| This information is encoded in the first-pass binary using identifiers |
| derived from the devicetree. This script extracts those identifiers |
| and replaces them with ones optimized for use with the devices |
| actually present. |
| |
| For example the sensor might have a first-pass handle defined by its |
| devicetree ordinal 52, with the I2C driver having ordinal 24 and the |
| GPIO controller ordinal 14. The runtime ordinal is the index of the |
| corresponding device in the static devicetree array, which might be 6, |
| 5, and 3, respectively. |
| |
| The output is a C source file that provides alternative definitions |
| for the array contents referenced from the immutable device objects. |
| In the final link these definitions supersede the ones in the |
| driver-specific object file. |
| """ |
| |
| import sys |
| import argparse |
| import os |
| import struct |
| import pickle |
| from distutils.version import LooseVersion |
| |
| import elftools |
| from elftools.elf.elffile import ELFFile |
| from elftools.elf.sections import SymbolTableSection |
| import elftools.elf.enums |
| |
| # This is needed to load edt.pickle files. |
| sys.path.append(os.path.join(os.path.dirname(__file__), |
| 'dts', 'python-devicetree', 'src')) |
| from devicetree import edtlib # pylint: disable=unused-import |
| |
| if LooseVersion(elftools.__version__) < LooseVersion('0.24'): |
| sys.exit("pyelftools is out of date, need version 0.24 or later") |
| |
| scr = os.path.basename(sys.argv[0]) |
| |
| def debug(text): |
| if not args.verbose: |
| return |
| sys.stdout.write(scr + ": " + text + "\n") |
| |
| def parse_args(): |
| global args |
| |
| parser = argparse.ArgumentParser( |
| description=__doc__, |
| formatter_class=argparse.RawDescriptionHelpFormatter) |
| |
| parser.add_argument("-k", "--kernel", required=True, |
| help="Input zephyr ELF binary") |
| parser.add_argument("-o", "--output-source", required=True, |
| help="Output source file") |
| |
| parser.add_argument("-v", "--verbose", action="store_true", |
| help="Print extra debugging information") |
| |
| parser.add_argument("-z", "--zephyr-base", |
| help="Path to current Zephyr base. If this argument \ |
| is not provided the environment will be checked for \ |
| the ZEPHYR_BASE environment variable.") |
| |
| parser.add_argument("-s", "--start-symbol", required=True, |
| help="Symbol name of the section which contains the \ |
| devices. The symbol name must point to the first \ |
| device in that section.") |
| |
| args = parser.parse_args() |
| if "VERBOSE" in os.environ: |
| args.verbose = 1 |
| |
| ZEPHYR_BASE = args.zephyr_base or os.getenv("ZEPHYR_BASE") |
| |
| if ZEPHYR_BASE is None: |
| sys.exit("-z / --zephyr-base not provided. Please provide " |
| "--zephyr-base or set ZEPHYR_BASE in environment") |
| |
| sys.path.insert(0, os.path.join(ZEPHYR_BASE, "scripts/dts")) |
| |
| |
| def symbol_data(elf, sym): |
| addr = sym.entry.st_value |
| len = sym.entry.st_size |
| for section in elf.iter_sections(): |
| start = section['sh_addr'] |
| end = start + section['sh_size'] |
| |
| if (start <= addr) and (addr + len) <= end: |
| offset = addr - section['sh_addr'] |
| return bytes(section.data()[offset:offset + len]) |
| |
| def symbol_handle_data(elf, sym): |
| data = symbol_data(elf, sym) |
| if data: |
| format = "<" if elf.little_endian else ">" |
| format += "%uh" % (len(data) / 2) |
| return struct.unpack(format, data) |
| |
| # These match the corresponding constants in <device.h> |
| DEVICE_HANDLE_SEP = -32768 |
| DEVICE_HANDLE_ENDS = 32767 |
| def handle_name(hdl): |
| if hdl == DEVICE_HANDLE_SEP: |
| return "DEVICE_HANDLE_SEP" |
| if hdl == DEVICE_HANDLE_ENDS: |
| return "DEVICE_HANDLE_ENDS" |
| if hdl == 0: |
| return "DEVICE_HANDLE_NULL" |
| return str(int(hdl)) |
| |
| class Device: |
| """ |
| Represents information about a device object and its references to other objects. |
| """ |
| def __init__(self, elf, ld_constants, sym, addr): |
| self.elf = elf |
| self.ld_constants = ld_constants |
| self.sym = sym |
| self.addr = addr |
| # Point to the handles instance associated with the device; |
| # assigned by correlating the device struct handles pointer |
| # value with the addr of a Handles instance. |
| self.__handles = None |
| |
| @property |
| def obj_handles(self): |
| """ |
| Returns the value from the device struct handles field, pointing to the |
| array of handles for devices this device depends on. |
| """ |
| if self.__handles is None: |
| data = symbol_data(self.elf, self.sym) |
| format = "<" if self.elf.little_endian else ">" |
| if self.elf.elfclass == 32: |
| format += "I" |
| size = 4 |
| else: |
| format += "Q" |
| size = 8 |
| offset = self.ld_constants["_DEVICE_STRUCT_HANDLES_OFFSET"] |
| self.__handles = struct.unpack(format, data[offset:offset + size])[0] |
| return self.__handles |
| |
| class Handles: |
| def __init__(self, sym, addr, handles, node): |
| self.sym = sym |
| self.addr = addr |
| self.handles = handles |
| self.node = node |
| self.dep_ord = None |
| self.dev_deps = None |
| self.ext_deps = None |
| |
| def main(): |
| parse_args() |
| |
| assert args.kernel, "--kernel ELF required to extract data" |
| elf = ELFFile(open(args.kernel, "rb")) |
| |
| edtser = os.path.join(os.path.split(args.kernel)[0], "edt.pickle") |
| with open(edtser, 'rb') as f: |
| edt = pickle.load(f) |
| |
| devices = [] |
| handles = [] |
| # Leading _ are stripped from the stored constant key |
| |
| want_constants = set([args.start_symbol, |
| "_DEVICE_STRUCT_SIZEOF", |
| "_DEVICE_STRUCT_HANDLES_OFFSET"]) |
| ld_constants = dict() |
| |
| for section in elf.iter_sections(): |
| if isinstance(section, SymbolTableSection): |
| for sym in section.iter_symbols(): |
| if sym.name in want_constants: |
| ld_constants[sym.name] = sym.entry.st_value |
| continue |
| if sym.entry.st_info.type != 'STT_OBJECT': |
| continue |
| if sym.name.startswith("__device"): |
| addr = sym.entry.st_value |
| if sym.name.startswith("__device_"): |
| devices.append(Device(elf, ld_constants, sym, addr)) |
| debug("device %s" % (sym.name,)) |
| elif sym.name.startswith("__devicehdl_"): |
| hdls = symbol_handle_data(elf, sym) |
| |
| # The first element of the hdls array is the dependency |
| # ordinal of the device, which identifies the devicetree |
| # node. |
| node = edt.dep_ord2node[hdls[0]] if (hdls and hdls[0] != 0) else None |
| handles.append(Handles(sym, addr, hdls, node)) |
| debug("handles %s %d %s" % (sym.name, hdls[0] if hdls else -1, node)) |
| |
| assert len(want_constants) == len(ld_constants), "linker map data incomplete" |
| |
| devices = sorted(devices, key = lambda k: k.sym.entry.st_value) |
| |
| device_start_addr = ld_constants[args.start_symbol] |
| device_size = 0 |
| |
| assert len(devices) == len(handles), 'mismatch devices and handles' |
| |
| used_nodes = set() |
| for handle in handles: |
| handle.device = None |
| for device in devices: |
| if handle.addr == device.obj_handles: |
| handle.device = device |
| break |
| device = handle.device |
| assert device, 'no device for %s' % (handle.sym.name,) |
| |
| device.handle = handle |
| |
| if device_size == 0: |
| device_size = device.sym.entry.st_size |
| |
| # The device handle is one plus the ordinal of this device in |
| # the device table. |
| device.dev_handle = 1 + int((device.sym.entry.st_value - device_start_addr) / device_size) |
| debug("%s dev ordinal %d" % (device.sym.name, device.dev_handle)) |
| |
| n = handle.node |
| if n is not None: |
| debug("%s dev ordinal %d\n\t%s" % (n.path, device.dev_handle, ' ; '.join(str(_) for _ in handle.handles))) |
| used_nodes.add(n) |
| n.__device = device |
| else: |
| debug("orphan %d" % (device.dev_handle,)) |
| hv = handle.handles |
| hvi = 1 |
| handle.dev_deps = [] |
| handle.ext_deps = [] |
| handle.dev_sups = [] |
| hdls = handle.dev_deps |
| while hvi < len(hv): |
| h = hv[hvi] |
| if h == DEVICE_HANDLE_ENDS: |
| break |
| if h == DEVICE_HANDLE_SEP: |
| if hdls == handle.dev_deps: |
| hdls = handle.ext_deps |
| else: |
| hdls = handle.dev_sups |
| else: |
| hdls.append(h) |
| n = edt |
| hvi += 1 |
| |
| # Compute the dependency graph induced from the full graph restricted to the |
| # the nodes that exist in the application. Note that the edges in the |
| # induced graph correspond to paths in the full graph. |
| root = edt.dep_ord2node[0] |
| assert root not in used_nodes |
| |
| for sn in used_nodes: |
| # Where we're storing the final set of nodes: these are all used |
| sn.__depends = set() |
| sn.__supports = set() |
| |
| deps = set(sn.depends_on) |
| debug("\nNode: %s\nOrig deps:\n\t%s" % (sn.path, "\n\t".join([dn.path for dn in deps]))) |
| while len(deps) > 0: |
| dn = deps.pop() |
| if dn in used_nodes: |
| # this is used |
| sn.__depends.add(dn) |
| elif dn != root: |
| # forward the dependency up one level |
| for ddn in dn.depends_on: |
| deps.add(ddn) |
| debug("Final deps:\n\t%s\n" % ("\n\t".join([ _dn.path for _dn in sn.__depends]))) |
| |
| sups = set(sn.required_by) |
| debug("\nOrig sups:\n\t%s" % ("\n\t".join([dn.path for dn in sups]))) |
| while len(sups) > 0: |
| dn = sups.pop() |
| if dn in used_nodes: |
| # this is used |
| sn.__supports.add(dn) |
| debug("\nFinal sups:\n\t%s" % ("\n\t".join([dn.path for dn in sn.__supports]))) |
| |
| with open(args.output_source, "w") as fp: |
| fp.write('#include <device.h>\n') |
| fp.write('#include <toolchain.h>\n') |
| |
| for dev in devices: |
| hs = dev.handle |
| assert hs, "no hs for %s" % (dev.sym.name,) |
| dep_paths = [] |
| ext_paths = [] |
| sup_paths = [] |
| hdls = [] |
| |
| sn = hs.node |
| if sn: |
| hdls.extend(dn.__device.dev_handle for dn in sn.__depends) |
| for dn in sn.depends_on: |
| if dn in sn.__depends: |
| dep_paths.append(dn.path) |
| else: |
| dep_paths.append('(%s)' % dn.path) |
| |
| # Force separator to signal start of injected dependencies |
| hdls.append(DEVICE_HANDLE_SEP) |
| if len(hs.ext_deps) > 0: |
| # TODO: map these to something smaller? |
| ext_paths.extend(map(str, hs.ext_deps)) |
| hdls.extend(hs.ext_deps) |
| |
| # Force separator to signal start of supported devices |
| hdls.append(DEVICE_HANDLE_SEP) |
| if len(hs.dev_sups) > 0: |
| for dn in sn.required_by: |
| if dn in sn.__supports: |
| sup_paths.append(dn.path) |
| else: |
| sup_paths.append('(%s)' % dn.path) |
| hdls.extend(dn.__device.dev_handle for dn in sn.__supports) |
| |
| # When CONFIG_USERSPACE is enabled the pre-built elf is |
| # also used to get hashes that identify kernel objects by |
| # address. We can't allow the size of any object in the |
| # final elf to change. We also must make sure at least one |
| # DEVICE_HANDLE_ENDS is inserted. |
| assert len(hdls) < len(hs.handles), "%s no DEVICE_HANDLE_ENDS inserted" % (dev.sym.name,) |
| while len(hdls) < len(hs.handles): |
| hdls.append(DEVICE_HANDLE_ENDS) |
| assert len(hdls) == len(hs.handles), "%s handle overflow" % (dev.sym.name,) |
| |
| lines = [ |
| '', |
| '/* %d : %s:' % (dev.dev_handle, (sn and sn.path) or "sysinit"), |
| ] |
| |
| if len(dep_paths) > 0: |
| lines.append(' * Direct Dependencies:') |
| lines.append(' * - %s' % ('\n * - '.join(dep_paths))) |
| if len(ext_paths) > 0: |
| lines.append(' * Injected Dependencies:') |
| lines.append(' * - %s' % ('\n * - '.join(ext_paths))) |
| if len(sup_paths) > 0: |
| lines.append(' * Supported:') |
| lines.append(' * - %s' % ('\n * - '.join(sup_paths))) |
| |
| lines.extend([ |
| ' */', |
| 'const device_handle_t __aligned(2) __attribute__((__section__(".__device_handles_pass2")))', |
| '%s[] = { %s };' % (hs.sym.name, ', '.join([handle_name(_h) for _h in hdls])), |
| '', |
| ]) |
| |
| fp.write('\n'.join(lines)) |
| |
| if __name__ == "__main__": |
| main() |
