blob: 4eca4855d0d044c268c8ba0208576cd68ce88a4f [file] [log] [blame]
#!/usr/bin/env python3
# Copyright (c) 2017 Intel Corporation
# SPDX-License-Identifier: Apache-2.0
import sys
import argparse
import pprint
import os
import struct
from distutils.version import LooseVersion
import elftools
from elftools.elf.elffile import ELFFile
from elftools.dwarf import descriptions
from elftools.elf.sections import SymbolTableSection
if LooseVersion(elftools.__version__) < LooseVersion('0.24'):
sys.stderr.write("pyelftools is out of date, need version 0.24 or later\n")
kobjects = [
subsystems = [
def subsystem_to_enum(subsys):
return "K_OBJ_DRIVER_" + subsys[:-11].upper()
def kobject_to_enum(ko):
return "K_OBJ_" + ko[2:].upper()
DW_OP_addr = 0x3
DW_OP_fbreg = 0x91
# Global type environment. Populated by pass 1.
type_env = {}
# --- debug stuff ---
scr = os.path.basename(sys.argv[0])
def debug(text):
if not args.verbose:
sys.stdout.write(scr + ": " + text + "\n")
def error(text):
sys.stderr.write("%s ERROR: %s\n" % (scr, text))
def debug_die(die, text):
fn, ln = get_filename_lineno(die)
debug("File '%s', line %d:" % (fn, ln))
debug(" %s" % text)
# --- type classes ----
class ArrayType:
def __init__(self, offset, num_members, member_type):
self.num_members = num_members
self.member_type = member_type
self.offset = offset
def __repr__(self):
return "<array of %d, size %d>" % (self.member_type, self.num_members)
def has_kobject(self):
if self.member_type not in type_env:
return False
return type_env[self.member_type].has_kobject()
def get_kobjects(self, addr):
mt = type_env[self.member_type]
objs = {}
for i in range(self.num_members):
objs.update(mt.get_kobjects(addr + (i * mt.size)))
return objs
class AggregateTypeMember:
def __init__(self, offset, member_name, member_type, member_offset):
self.member_name = member_name
self.member_type = member_type
self.member_offset = member_offset
def __repr__(self):
return "<member %s, type %d, offset %d>" % (self.member_name,
self.member_type, self.member_offset)
def has_kobject(self):
if self.member_type not in type_env:
return False
return type_env[self.member_type].has_kobject()
def get_kobjects(self, addr):
mt = type_env[self.member_type]
return mt.get_kobjects(addr + self.member_offset)
class ConstType:
def __init__(self, child_type):
self.child_type = child_type
def __repr__(self):
return "<const %d>" % self.child_type
def has_kobject(self):
if self.child_type not in type_env:
return False
return type_env[self.child_type].has_kobject()
def get_kobjects(self, addr):
return type_env[self.child_type].get_kobjects(addr)
class AggregateType:
def __init__(self, offset, name, size): = name
self.size = size
self.offset = offset
self.members = []
def add_member(self, member):
def __repr__(self):
return "<struct %s, with %s>" % (, self.members)
def has_kobject(self):
result = False
bad_members = []
for member in self.members:
if member.has_kobject():
result = True
# Don't need to consider this again, just remove it
for bad_member in bad_members:
return result
def get_kobjects(self, addr):
objs = {}
for member in self.members:
return objs
class KobjectType:
def __init__(self, offset, name, size, api=False): = name
self.size = size
self.offset = offset
self.api = api
def __repr__(self):
return "<kobject %s>" %
def has_kobject(self):
return True
def get_kobjects(self, addr):
return {addr: self}
# --- helper functions for getting data from DIEs ---
def die_get_name(die):
if not 'DW_AT_name' in die.attributes:
return None
return die.attributes["DW_AT_name"].value.decode("utf-8")
def die_get_type_offset(die):
if not 'DW_AT_type' in die.attributes:
return 0
return die.attributes["DW_AT_type"].value +
def die_get_byte_size(die):
if not 'DW_AT_byte_size' in die.attributes:
return 0
return die.attributes["DW_AT_byte_size"].value
def analyze_die_struct(die):
name = die_get_name(die) or "<anon>"
offset = die.offset
size = die_get_byte_size(die)
# Incomplete type
if not size:
if name in kobjects:
type_env[offset] = KobjectType(offset, name, size)
elif name in subsystems:
type_env[offset] = KobjectType(offset, name, size, api=True)
at = AggregateType(offset, name, size)
type_env[offset] = at
for child in die.iter_children():
if child.tag != "DW_TAG_member":
child_type = die_get_type_offset(child)
member_offset = child.attributes["DW_AT_data_member_location"].value
cname = die_get_name(child) or "<anon>"
m = AggregateTypeMember(child.offset, cname, child_type,
def analyze_die_const(die):
type_offset = die_get_type_offset(die)
if not type_offset:
type_env[die.offset] = ConstType(type_offset)
def analyze_die_array(die):
type_offset = die_get_type_offset(die)
elements = 1
size_found = False
for child in die.iter_children():
if child.tag != "DW_TAG_subrange_type":
if "DW_AT_upper_bound" not in child.attributes:
ub = child.attributes["DW_AT_upper_bound"]
if not ub.form.startswith("DW_FORM_data"):
size_found = True
elements = elements * (ub.value + 1)
if not size_found:
type_env[die.offset] = ArrayType(die.offset, elements, type_offset)
def addr_deref(elf, addr):
for section in elf.iter_sections():
start = section['sh_addr']
end = start + section['sh_size']
if addr >= start and addr < end:
data =
offset = addr - start
return struct.unpack("<I" if args.little_endian else ">I",
return 0
def device_get_api_addr(elf, addr):
return addr_deref(elf, addr + 4)
def get_filename_lineno(die):
lp_header = die.dwarfinfo.line_program_for_CU(
files = lp_header["file_entry"]
includes = lp_header["include_directory"]
fileinfo = files[die.attributes["DW_AT_decl_file"].value - 1]
filename ="utf-8")
filedir = includes[fileinfo.dir_index - 1].decode("utf-8")
path = os.path.join(filedir, filename)
lineno = die.attributes["DW_AT_decl_line"].value
return (path, lineno)
def find_kobjects(elf, syms):
if not elf.has_dwarf_info():
sys.stderr.write("ELF file has no DWARF information\n");
kram_start = syms["__kernel_ram_start"]
kram_end = syms["__kernel_ram_end"]
krom_start = syms["_image_rom_start"]
krom_end = syms["_image_rom_end"]
di = elf.get_dwarf_info()
variables = []
# Step 1: collect all type information.
for CU in di.iter_CUs():
CU_path = CU.get_top_DIE().get_full_path()
lp = di.line_program_for_CU(CU)
for idx, die in enumerate(CU.iter_DIEs()):
# Unions are disregarded, kernel objects should never be union
# members since the memory is not dedicated to that object and
# could be something else
if die.tag == "DW_TAG_structure_type":
elif die.tag == "DW_TAG_const_type":
elif die.tag == "DW_TAG_array_type":
elif die.tag == "DW_TAG_variable":
# Step 2: filter type_env to only contain kernel objects, or structs and
# arrays of kernel objects
bad_offsets = []
for offset, type_object in type_env.items():
if not type_object.has_kobject():
for offset in bad_offsets:
del type_env[offset]
# Step 3: Now that we know all the types we are looking for, examine
# all variables
all_objs = {}
# Gross hack, see below
work_q_found = False
for die in variables:
name = die_get_name(die)
if not name:
type_offset = die_get_type_offset(die)
# Is this a kernel object, or a structure containing kernel objects?
if type_offset not in type_env:
if "DW_AT_declaration" in die.attributes:
# FIXME: why does k_sys_work_q not resolve an address in the DWARF
# data??? Every single instance it finds is an extern definition
# but not the actual instance in system_work_q.c
# Is there something weird about how lib-y stuff is linked?
if name == "k_sys_work_q" and not work_q_found and name in syms:
addr = syms[name]
work_q_found = True
if "DW_AT_location" not in die.attributes:
debug_die(die, "No location information for object '%s'; possibly stack allocated"
% name)
loc = die.attributes["DW_AT_location"]
if loc.form != "DW_FORM_exprloc":
debug_die(die, "kernel object '%s' unexpected location format" % name)
opcode = loc.value[0]
if opcode != DW_OP_addr:
# Check if frame pointer offset DW_OP_fbreg
if opcode == DW_OP_fbreg:
debug_die(die, "kernel object '%s' found on stack" % name)
debug_die(die, "kernel object '%s' unexpected exprloc opcode %s"
% (name, hex(opcode)))
addr = (loc.value[1] | (loc.value[2] << 8) | (loc.value[3] << 16) |
(loc.value[4] << 24))
if addr == 0:
# Never linked; gc-sections deleted it
if ((addr < kram_start or addr >= kram_end)
and (addr < krom_start or addr >= krom_end)):
debug_die(die, "object '%s' found in invalid location %s" %
(name, hex(addr)));
type_obj = type_env[type_offset]
objs = type_obj.get_kobjects(addr)
debug("symbol '%s' at %s contains %d object(s)" % (name, hex(addr),
# Step 4: objs is a dictionary mapping variable memory addresses to their
# associated type objects. Now that we have seen all variables and can
# properly look up API structs, convert this into a dictionary mapping
# variables to the C enumeration of what kernel object type it is.
ret = {}
for addr, ko in all_objs.items():
# API structs don't get into the gperf table
if ko.api:
if != "device":
# Not a device struct so we immediately know its type
ret[addr] = kobject_to_enum(
# Device struct. Need to get the address of its API struct, if it has
# one.
apiaddr = device_get_api_addr(elf, addr)
if apiaddr not in all_objs:
# API struct does not correspond to a known subsystem, skip it
apiobj = all_objs[apiaddr]
ret[addr] = subsystem_to_enum(
debug("found %d kernel object instances total" % len(ret))
return ret
header = """%compare-lengths
%define lookup-function-name _k_object_lookup
#include <kernel.h>
#include <string.h>
struct _k_object;
# Different versions of gperf have different prototypes for the lookup function,
# best to implement the wrapper here. The pointer value itself is turned into
# a string, we told gperf to expect binary strings that are not NULL-terminated.
footer = """%%
struct _k_object *_k_object_find(void *obj)
return _k_object_lookup((const char *)obj, sizeof(void *));
def write_gperf_table(fp, objs, static_begin, static_end):
for obj_addr, obj_type in objs.items():
# pre-initialized objects fall within this memory range, they are
# either completely initialized at build time, or done automatically
# at boot during some PRE_KERNEL_* phase
initialized = obj_addr >= static_begin and obj_addr < static_end
byte_str = struct.pack("<I" if args.little_endian else ">I", obj_addr)
for byte in byte_str:
val = "\\x%02x" % byte
fp.write("\",{},%s,%s\n" % (obj_type,
"K_OBJ_FLAG_INITIALIZED" if initialized else "0"))
def get_symbols(obj):
for section in obj.iter_sections():
if isinstance(section, SymbolTableSection):
return { sym.entry.st_value
for sym in section.iter_symbols()}
raise LookupError("Could not find symbol table")
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", required=True,
help="Output list of kernel object addresses for gperf use")
parser.add_argument("-v", "--verbose", action="store_true",
help="Print extra debugging information")
args = parser.parse_args()
def main():
with open(args.kernel, "rb") as fp:
elf = ELFFile(fp)
args.little_endian = elf.little_endian
syms = get_symbols(elf)
objs = find_kobjects(elf, syms)
with open(args.output, "w") as fp:
write_gperf_table(fp, objs, syms["_static_kernel_objects_begin"],
if __name__ == "__main__":