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scripts: merge elf_helper into gen_kobject_list

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No need for this to be separated out any more.
Minimal changes made to get it to still work.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2020-03-11 14:17:56 -07:00 • committed by Andrew Boie
commit fc2f7c3a55
3 changed files with 601 additions and 617 deletions
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1
CODEOWNERS
View file

@ -375,7 +375,6 @@
/scripts/coccicheck @himanshujha199640 @JuliaLawall
/scripts/coccinelle/ @himanshujha199640 @JuliaLawall
/scripts/kconfig/ @ulfalizer
/scripts/elf_helper.py @andrewboie
/scripts/sanity_chk/expr_parser.py @nashif
/scripts/gen_app_partitions.py @andrewboie
/scripts/dts/ @ulfalizer @galak

615
scripts/elf_helper.py
View file

@ -1,615 +0,0 @@
#!/usr/bin/env python3
#
# Copyright (c) 2017-2018 Linaro
#
# SPDX-License-Identifier: Apache-2.0
import sys
import os
import struct
from distutils.version import LooseVersion
from collections import OrderedDict
import elftools
from elftools.elf.elffile import ELFFile
from elftools.elf.sections import SymbolTableSection
if LooseVersion(elftools.__version__) < LooseVersion('0.24'):
sys.exit("pyelftools is out of date, need version 0.24 or later")
def subsystem_to_enum(subsys):
return "K_OBJ_DRIVER_" + subsys[:-11].upper()
def kobject_to_enum(kobj):
if kobj.startswith("k_") or kobj.startswith("z_"):
name = kobj[2:]
else:
name = kobj
return "K_OBJ_%s" % name.upper()
DW_OP_addr = 0x3
DW_OP_fbreg = 0x91
STACK_TYPE = "z_thread_stack_element"
thread_counter = 0
sys_mutex_counter = 0
futex_counter = 0
stack_counter = 0
# Global type environment. Populated by pass 1.
type_env = {}
extern_env = {}
kobjects = {}
subsystems = {}
# --- debug stuff ---
scr = os.path.basename(sys.argv[0])
# --- type classes ----
class KobjectInstance:
def __init__(self, type_obj, addr):
global thread_counter
global sys_mutex_counter
global futex_counter
global stack_counter
self.addr = addr
self.type_obj = type_obj
# Type name determined later since drivers needs to look at the
# API struct address
self.type_name = None
if self.type_obj.name == "k_thread":
# Assign an ID for this thread object, used to track its
# permissions to other kernel objects
self.data = thread_counter
thread_counter = thread_counter + 1
elif self.type_obj.name == "sys_mutex":
self.data = "&kernel_mutexes[%d]" % sys_mutex_counter
sys_mutex_counter += 1
elif self.type_obj.name == "k_futex":
self.data = "&futex_data[%d]" % futex_counter
futex_counter += 1
elif self.type_obj.name == STACK_TYPE:
stack_counter += 1
else:
self.data = 0
class KobjectType:
def __init__(self, offset, name, size, api=False):
self.name = name
self.size = size
self.offset = offset
self.api = api
def __repr__(self):
return "<kobject %s>" % self.name
@staticmethod
def has_kobject():
return True
def get_kobjects(self, addr):
return {addr: KobjectInstance(self, addr)}
class ArrayType:
def __init__(self, offset, elements, member_type):
self.elements = elements
self.member_type = member_type
self.offset = offset
def __repr__(self):
return "<array of %d>" % self.member_type
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]
# Stacks are arrays of _k_stack_element_t but we want to treat
# the whole array as one kernel object (a thread stack)
# Data value gets set to size of entire region
if isinstance(mt, KobjectType) and mt.name == STACK_TYPE:
# An array of stacks appears as a multi-dimensional array.
# The last size is the size of each stack. We need to track
# each stack within the array, not as one huge stack object.
*dimensions, stacksize = self.elements
num_members = 1
for e in dimensions:
num_members = num_members * e
ret = {}
for i in range(num_members):
a = addr + (i * stacksize)
o = mt.get_kobjects(a)
o[a].data = stacksize
ret.update(o)
return ret
objs = {}
# Multidimensional array flattened out
num_members = 1
for e in self.elements:
num_members = num_members * e
for i in range(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
if isinstance(member_offset, list):
# DWARF v2, location encoded as set of operations
# only "DW_OP_plus_uconst" with ULEB128 argument supported
if member_offset[0] == 0x23:
self.member_offset = member_offset[1] & 0x7f
for i in range(1, len(member_offset)-1):
if member_offset[i] & 0x80:
self.member_offset += (
member_offset[i+1] & 0x7f) << i*7
else:
raise Exception("not yet supported location operation (%s:%d:%d)" %
(self.member_name, self.member_type, member_offset[0]))
else:
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):
self.name = name
self.size = size
self.offset = offset
self.members = []
def add_member(self, member):
self.members.append(member)
def __repr__(self):
return "<struct %s, with %s>" % (self.name, self.members)
def has_kobject(self):
result = False
bad_members = []
for member in self.members:
if member.has_kobject():
result = True
else:
bad_members.append(member)
# Don't need to consider this again, just remove it
for bad_member in bad_members:
self.members.remove(bad_member)
return result
def get_kobjects(self, addr):
objs = {}
for member in self.members:
objs.update(member.get_kobjects(addr))
return objs
# --- helper functions for getting data from DIEs ---
def die_get_spec(die):
if 'DW_AT_specification' not in die.attributes:
return None
spec_val = die.attributes["DW_AT_specification"].value
# offset of the DW_TAG_variable for the extern declaration
offset = spec_val + die.cu.cu_offset
return extern_env.get(offset)
def die_get_name(die):
if 'DW_AT_name' not in die.attributes:
die = die_get_spec(die)
if not die:
return None
return die.attributes["DW_AT_name"].value.decode("utf-8")
def die_get_type_offset(die):
if 'DW_AT_type' not in die.attributes:
die = die_get_spec(die)
if not die:
return None
return die.attributes["DW_AT_type"].value + die.cu.cu_offset
def die_get_byte_size(die):
if 'DW_AT_byte_size' not 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:
return
if name in kobjects:
type_env[offset] = KobjectType(offset, name, size)
elif name in subsystems:
type_env[offset] = KobjectType(offset, name, size, api=True)
else:
at = AggregateType(offset, name, size)
type_env[offset] = at
for child in die.iter_children():
if child.tag != "DW_TAG_member":
continue
data_member_location = child.attributes.get("DW_AT_data_member_location")
if not data_member_location:
continue
child_type = die_get_type_offset(child)
member_offset = data_member_location.value
cname = die_get_name(child) or "<anon>"
m = AggregateTypeMember(child.offset, cname, child_type,
member_offset)
at.add_member(m)
return
def analyze_die_const(die):
type_offset = die_get_type_offset(die)
if not type_offset:
return
type_env[die.offset] = ConstType(type_offset)
def analyze_die_array(die):
type_offset = die_get_type_offset(die)
elements = []
for child in die.iter_children():
if child.tag != "DW_TAG_subrange_type":
continue
if "DW_AT_upper_bound" not in child.attributes:
continue
ub = child.attributes["DW_AT_upper_bound"]
if not ub.form.startswith("DW_FORM_data"):
continue
elements.append(ub.value + 1)
if not elements:
if type_offset in type_env.keys():
mt = type_env[type_offset]
if mt.has_kobject():
if isinstance(mt, KobjectType) and mt.name == STACK_TYPE:
elements.append(1)
type_env[die.offset] = ArrayType(die.offset, elements, type_offset)
else:
type_env[die.offset] = ArrayType(die.offset, elements, type_offset)
def analyze_typedef(die):
type_offset = die_get_type_offset(die)
if type_offset not in type_env.keys():
return
type_env[die.offset] = type_env[type_offset]
def unpack_pointer(elf, data, offset):
endian_code = "<" if elf.little_endian else ">"
if elf.elfclass == 32:
size_code = "I"
size = 4
else:
size_code = "Q"
size = 8
return struct.unpack(endian_code + size_code,
data[offset:offset + size])[0]
def addr_deref(elf, addr):
for section in elf.iter_sections():
start = section['sh_addr']
end = start + section['sh_size']
if start <= addr < end:
data = section.data()
offset = addr - start
return unpack_pointer(elf, data, offset)
return 0
def device_get_api_addr(elf, addr):
# Read device->driver API
offset = 4 if elf.elfclass == 32 else 8
return addr_deref(elf, addr + offset)
def get_filename_lineno(die):
lp_header = die.dwarfinfo.line_program_for_CU(die.cu).header
files = lp_header["file_entry"]
includes = lp_header["include_directory"]
fileinfo = files[die.attributes["DW_AT_decl_file"].value - 1]
filename = fileinfo.name.decode("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)
class ElfHelper:
def __init__(self, filename, verbose, kobjs, subs):
self.verbose = verbose
self.fp = open(filename, "rb")
self.elf = ELFFile(self.fp)
self.little_endian = self.elf.little_endian
global kobjects
global subsystems
kobjects = kobjs
subsystems = subs
def find_kobjects(self, syms):
if not self.elf.has_dwarf_info():
sys.exit("ELF file has no DWARF information")
app_smem_start = syms["_app_smem_start"]
app_smem_end = syms["_app_smem_end"]
di = self.elf.get_dwarf_info()
variables = []
# Step 1: collect all type information.
for CU in di.iter_CUs():
for die in 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":
analyze_die_struct(die)
elif die.tag == "DW_TAG_const_type":
analyze_die_const(die)
elif die.tag == "DW_TAG_array_type":
analyze_die_array(die)
elif die.tag == "DW_TAG_typedef":
analyze_typedef(die)
elif die.tag == "DW_TAG_variable":
variables.append(die)
# 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():
bad_offsets.append(offset)
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 = {}
for die in variables:
name = die_get_name(die)
if not name:
continue
if name.startswith("__device_sys_init"):
# Boot-time initialization function; not an actual device
continue
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:
continue
if "DW_AT_declaration" in die.attributes:
# Extern declaration, only used indirectly
extern_env[die.offset] = die
continue
if "DW_AT_location" not in die.attributes:
self.debug_die(
die,
"No location information for object '%s'; possibly"
" stack allocated" % name)
continue
loc = die.attributes["DW_AT_location"]
if loc.form != "DW_FORM_exprloc" and \
loc.form != "DW_FORM_block1":
self.debug_die(
die,
"kernel object '%s' unexpected location format" %
name)
continue
opcode = loc.value[0]
if opcode != DW_OP_addr:
# Check if frame pointer offset DW_OP_fbreg
if opcode == DW_OP_fbreg:
self.debug_die(die, "kernel object '%s' found on stack" %
name)
else:
self.debug_die(
die,
"kernel object '%s' unexpected exprloc opcode %s" %
(name, hex(opcode)))
continue
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
continue
type_obj = type_env[type_offset]
objs = type_obj.get_kobjects(addr)
all_objs.update(objs)
self.debug("symbol '%s' at %s contains %d object(s)"
% (name, hex(addr), len(objs)))
# 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.type_obj.api:
continue
_, user_ram_allowed = kobjects[ko.type_obj.name]
if not user_ram_allowed and app_smem_start <= addr < app_smem_end:
self.debug_die(die,
"object '%s' found in invalid location %s"
% (name, hex(addr)))
continue
if ko.type_obj.name != "device":
# Not a device struct so we immediately know its type
ko.type_name = kobject_to_enum(ko.type_obj.name)
ret[addr] = ko
continue
# Device struct. Need to get the address of its API struct,
# if it has one.
apiaddr = device_get_api_addr(self.elf, addr)
if apiaddr not in all_objs:
if apiaddr == 0:
self.debug("device instance at 0x%x has no associated subsystem"
% addr)
else:
self.debug("device instance at 0x%x has unknown API 0x%x"
% (addr, apiaddr))
# API struct does not correspond to a known subsystem, skip it
continue
apiobj = all_objs[apiaddr]
ko.type_name = subsystem_to_enum(apiobj.type_obj.name)
ret[addr] = ko
self.debug("found %d kernel object instances total" % len(ret))
# 1. Before python 3.7 dict order is not guaranteed. With Python
# 3.5 it doesn't seem random with *integer* keys but can't
# rely on that.
# 2. OrderedDict means _insertion_ order, so not enough because
# built from other (random!) dicts: need to _sort_ first.
# 3. Sorting memory address looks good.
return OrderedDict(sorted(ret.items()))
def get_symbols(self):
for section in self.elf.iter_sections():
if isinstance(section, SymbolTableSection):
return {sym.name: sym.entry.st_value
for sym in section.iter_symbols()}
raise LookupError("Could not find symbol table")
def debug(self, text):
if not self.verbose:
return
sys.stdout.write(scr + ": " + text + "\n")
@staticmethod
def error(text):
sys.exit("%s ERROR: %s" % (scr, text))
def debug_die(self, die, text):
fn, ln = get_filename_lineno(die)
self.debug(str(die))
self.debug("File '%s', line %d:" % (fn, ln))
self.debug(" %s" % text)
@staticmethod
def get_thread_counter():
return thread_counter
@staticmethod
def get_sys_mutex_counter():
return sys_mutex_counter
@staticmethod
def get_futex_counter():
return futex_counter
@staticmethod
def get_stack_counter():
return stack_counter

602
scripts/gen_kobject_list.py
View file

@ -57,7 +57,14 @@ import math
import os
import struct
import json
from elf_helper import ElfHelper, kobject_to_enum
from distutils.version import LooseVersion
import elftools
from elftools.elf.elffile import ELFFile
from elftools.elf.sections import SymbolTableSection
if LooseVersion(elftools.__version__) < LooseVersion('0.24'):
sys.exit("pyelftools is out of date, need version 0.24 or later")
from collections import OrderedDict
@ -91,6 +98,14 @@ kobjects = OrderedDict([
("k_futex", (None, True))
])
def kobject_to_enum(kobj):
if kobj.startswith("k_") or kobj.startswith("z_"):
name = kobj[2:]
else:
name = kobj
return "K_OBJ_%s" % name.upper()
subsystems = [
# Editing the list is deprecated, add the __subsystem sentinal to your driver
# api declaration instead. e.x.
@ -100,6 +115,591 @@ subsystems = [
#};
]
def subsystem_to_enum(subsys):
return "K_OBJ_DRIVER_" + subsys[:-11].upper()
# --- debug stuff ---
scr = os.path.basename(sys.argv[0])
# -- ELF processing
DW_OP_addr = 0x3
DW_OP_fbreg = 0x91
STACK_TYPE = "z_thread_stack_element"
thread_counter = 0
sys_mutex_counter = 0
futex_counter = 0
stack_counter = 0
# Global type environment. Populated by pass 1.
type_env = {}
extern_env = {}
elh_kobjects = {}
elh_subsystems = {}
class KobjectInstance:
def __init__(self, type_obj, addr):
global thread_counter
global sys_mutex_counter
global futex_counter
global stack_counter
self.addr = addr
self.type_obj = type_obj
# Type name determined later since drivers needs to look at the
# API struct address
self.type_name = None
if self.type_obj.name == "k_thread":
# Assign an ID for this thread object, used to track its
# permissions to other kernel objects
self.data = thread_counter
thread_counter = thread_counter + 1
elif self.type_obj.name == "sys_mutex":
self.data = "&kernel_mutexes[%d]" % sys_mutex_counter
sys_mutex_counter += 1
elif self.type_obj.name == "k_futex":
self.data = "&futex_data[%d]" % futex_counter
futex_counter += 1
elif self.type_obj.name == STACK_TYPE:
stack_counter += 1
else:
self.data = 0
class KobjectType:
def __init__(self, offset, name, size, api=False):
self.name = name
self.size = size
self.offset = offset
self.api = api
def __repr__(self):
return "<kobject %s>" % self.name
@staticmethod
def has_kobject():
return True
def get_kobjects(self, addr):
return {addr: KobjectInstance(self, addr)}
class ArrayType:
def __init__(self, offset, elements, member_type):
self.elements = elements
self.member_type = member_type
self.offset = offset
def __repr__(self):
return "<array of %d>" % self.member_type
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]
# Stacks are arrays of _k_stack_element_t but we want to treat
# the whole array as one kernel object (a thread stack)
# Data value gets set to size of entire region
if isinstance(mt, KobjectType) and mt.name == STACK_TYPE:
# An array of stacks appears as a multi-dimensional array.
# The last size is the size of each stack. We need to track
# each stack within the array, not as one huge stack object.
*dimensions, stacksize = self.elements
num_members = 1
for e in dimensions:
num_members = num_members * e
ret = {}
for i in range(num_members):
a = addr + (i * stacksize)
o = mt.get_kobjects(a)
o[a].data = stacksize
ret.update(o)
return ret
objs = {}
# Multidimensional array flattened out
num_members = 1
for e in self.elements:
num_members = num_members * e
for i in range(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
if isinstance(member_offset, list):
# DWARF v2, location encoded as set of operations
# only "DW_OP_plus_uconst" with ULEB128 argument supported
if member_offset[0] == 0x23:
self.member_offset = member_offset[1] & 0x7f
for i in range(1, len(member_offset)-1):
if member_offset[i] & 0x80:
self.member_offset += (
member_offset[i+1] & 0x7f) << i*7
else:
raise Exception("not yet supported location operation (%s:%d:%d)" %
(self.member_name, self.member_type, member_offset[0]))
else:
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):
self.name = name
self.size = size
self.offset = offset
self.members = []
def add_member(self, member):
self.members.append(member)
def __repr__(self):
return "<struct %s, with %s>" % (self.name, self.members)
def has_kobject(self):
result = False
bad_members = []
for member in self.members:
if member.has_kobject():
result = True
else:
bad_members.append(member)
# Don't need to consider this again, just remove it
for bad_member in bad_members:
self.members.remove(bad_member)
return result
def get_kobjects(self, addr):
objs = {}
for member in self.members:
objs.update(member.get_kobjects(addr))
return objs
# --- helper functions for getting data from DIEs ---
def die_get_spec(die):
if 'DW_AT_specification' not in die.attributes:
return None
spec_val = die.attributes["DW_AT_specification"].value
# offset of the DW_TAG_variable for the extern declaration
offset = spec_val + die.cu.cu_offset
return extern_env.get(offset)
def die_get_name(die):
if 'DW_AT_name' not in die.attributes:
die = die_get_spec(die)
if not die:
return None
return die.attributes["DW_AT_name"].value.decode("utf-8")
def die_get_type_offset(die):
if 'DW_AT_type' not in die.attributes:
die = die_get_spec(die)
if not die:
return None
return die.attributes["DW_AT_type"].value + die.cu.cu_offset
def die_get_byte_size(die):
if 'DW_AT_byte_size' not 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:
return
if name in elh_kobjects:
type_env[offset] = KobjectType(offset, name, size)
elif name in elh_subsystems:
type_env[offset] = KobjectType(offset, name, size, api=True)
else:
at = AggregateType(offset, name, size)
type_env[offset] = at
for child in die.iter_children():
if child.tag != "DW_TAG_member":
continue
data_member_location = child.attributes.get("DW_AT_data_member_location")
if not data_member_location:
continue
child_type = die_get_type_offset(child)
member_offset = data_member_location.value
cname = die_get_name(child) or "<anon>"
m = AggregateTypeMember(child.offset, cname, child_type,
member_offset)
at.add_member(m)
return
def analyze_die_const(die):
type_offset = die_get_type_offset(die)
if not type_offset:
return
type_env[die.offset] = ConstType(type_offset)
def analyze_die_array(die):
type_offset = die_get_type_offset(die)
elements = []
for child in die.iter_children():
if child.tag != "DW_TAG_subrange_type":
continue
if "DW_AT_upper_bound" not in child.attributes:
continue
ub = child.attributes["DW_AT_upper_bound"]
if not ub.form.startswith("DW_FORM_data"):
continue
elements.append(ub.value + 1)
if not elements:
if type_offset in type_env.keys():
mt = type_env[type_offset]
if mt.has_kobject():
if isinstance(mt, KobjectType) and mt.name == STACK_TYPE:
elements.append(1)
type_env[die.offset] = ArrayType(die.offset, elements, type_offset)
else:
type_env[die.offset] = ArrayType(die.offset, elements, type_offset)
def analyze_typedef(die):
type_offset = die_get_type_offset(die)
if type_offset not in type_env.keys():
return
type_env[die.offset] = type_env[type_offset]
def unpack_pointer(elf, data, offset):
endian_code = "<" if elf.little_endian else ">"
if elf.elfclass == 32:
size_code = "I"
size = 4
else:
size_code = "Q"
size = 8
return struct.unpack(endian_code + size_code,
data[offset:offset + size])[0]
def addr_deref(elf, addr):
for section in elf.iter_sections():
start = section['sh_addr']
end = start + section['sh_size']
if start <= addr < end:
data = section.data()
offset = addr - start
return unpack_pointer(elf, data, offset)
return 0
def device_get_api_addr(elf, addr):
# Read device->driver API
offset = 4 if elf.elfclass == 32 else 8
return addr_deref(elf, addr + offset)
def get_filename_lineno(die):
lp_header = die.dwarfinfo.line_program_for_CU(die.cu).header
files = lp_header["file_entry"]
includes = lp_header["include_directory"]
fileinfo = files[die.attributes["DW_AT_decl_file"].value - 1]
filename = fileinfo.name.decode("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)
class ElfHelper:
def __init__(self, filename, verbose, kobjs, subs):
self.verbose = verbose
self.fp = open(filename, "rb")
self.elf = ELFFile(self.fp)
self.little_endian = self.elf.little_endian
global elh_kobjects
global elh_subsystems
elh_kobjects = kobjs
elh_subsystems = subs
def find_kobjects(self, syms):
if not self.elf.has_dwarf_info():
sys.exit("ELF file has no DWARF information")
app_smem_start = syms["_app_smem_start"]
app_smem_end = syms["_app_smem_end"]
di = self.elf.get_dwarf_info()
variables = []
# Step 1: collect all type information.
for CU in di.iter_CUs():
for die in 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":
analyze_die_struct(die)
elif die.tag == "DW_TAG_const_type":
analyze_die_const(die)
elif die.tag == "DW_TAG_array_type":
analyze_die_array(die)
elif die.tag == "DW_TAG_typedef":
analyze_typedef(die)
elif die.tag == "DW_TAG_variable":
variables.append(die)
# 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():
bad_offsets.append(offset)
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 = {}
for die in variables:
name = die_get_name(die)
if not name:
continue
if name.startswith("__device_sys_init"):
# Boot-time initialization function; not an actual device
continue
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:
continue
if "DW_AT_declaration" in die.attributes:
# Extern declaration, only used indirectly
extern_env[die.offset] = die
continue
if "DW_AT_location" not in die.attributes:
self.debug_die(
die,
"No location information for object '%s'; possibly"
" stack allocated" % name)
continue
loc = die.attributes["DW_AT_location"]
if loc.form != "DW_FORM_exprloc" and \
loc.form != "DW_FORM_block1":
self.debug_die(
die,
"kernel object '%s' unexpected location format" %
name)
continue
opcode = loc.value[0]
if opcode != DW_OP_addr:
# Check if frame pointer offset DW_OP_fbreg
if opcode == DW_OP_fbreg:
self.debug_die(die, "kernel object '%s' found on stack" %
name)
else:
self.debug_die(
die,
"kernel object '%s' unexpected exprloc opcode %s" %
(name, hex(opcode)))
continue
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
continue
type_obj = type_env[type_offset]
objs = type_obj.get_kobjects(addr)
all_objs.update(objs)
self.debug("symbol '%s' at %s contains %d object(s)"
% (name, hex(addr), len(objs)))
# 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.type_obj.api:
continue
_, user_ram_allowed = elh_kobjects[ko.type_obj.name]
if not user_ram_allowed and app_smem_start <= addr < app_smem_end:
self.debug_die(die,
"object '%s' found in invalid location %s"
% (name, hex(addr)))
continue
if ko.type_obj.name != "device":
# Not a device struct so we immediately know its type
ko.type_name = kobject_to_enum(ko.type_obj.name)
ret[addr] = ko
continue
# Device struct. Need to get the address of its API struct,
# if it has one.
apiaddr = device_get_api_addr(self.elf, addr)
if apiaddr not in all_objs:
if apiaddr == 0:
self.debug("device instance at 0x%x has no associated subsystem"
% addr)
else:
self.debug("device instance at 0x%x has unknown API 0x%x"
% (addr, apiaddr))
# API struct does not correspond to a known subsystem, skip it
continue
apiobj = all_objs[apiaddr]
ko.type_name = subsystem_to_enum(apiobj.type_obj.name)
ret[addr] = ko
self.debug("found %d kernel object instances total" % len(ret))
# 1. Before python 3.7 dict order is not guaranteed. With Python
# 3.5 it doesn't seem random with *integer* keys but can't
# rely on that.
# 2. OrderedDict means _insertion_ order, so not enough because
# built from other (random!) dicts: need to _sort_ first.
# 3. Sorting memory address looks good.
return OrderedDict(sorted(ret.items()))
def get_symbols(self):
for section in self.elf.iter_sections():
if isinstance(section, SymbolTableSection):
return {sym.name: sym.entry.st_value
for sym in section.iter_symbols()}
raise LookupError("Could not find symbol table")
def debug(self, text):
if not self.verbose:
return
sys.stdout.write(scr + ": " + text + "\n")
@staticmethod
def error(text):
sys.exit("%s ERROR: %s" % (scr, text))
def debug_die(self, die, text):
fn, ln = get_filename_lineno(die)
self.debug(str(die))
self.debug("File '%s', line %d:" % (fn, ln))
self.debug(" %s" % text)
@staticmethod
def get_thread_counter():
return thread_counter
@staticmethod
def get_sys_mutex_counter():
return sys_mutex_counter
@staticmethod
def get_futex_counter():
return futex_counter
@staticmethod
def get_stack_counter():
return stack_counter
# -- GPERF generation logic
header = """%compare-lengths
%define lookup-function-name z_object_lookup
%language=ANSI-C