| #!/usr/bin/env python3 |
| # |
| # Copyright (c) 2017 Intel Corporation |
| # |
| # SPDX-License-Identifier: Apache-2.0 |
| """ |
| Script to generate gperf tables of kernel object metadata |
| |
| User mode threads making system calls reference kernel objects by memory |
| address, as the kernel/driver APIs in Zephyr are the same for both user |
| and supervisor contexts. It is necessary for the kernel to be able to |
| validate accesses to kernel objects to make the following assertions: |
| |
| - That the memory address points to a kernel object |
| |
| - The kernel object is of the expected type for the API being invoked |
| |
| - The kernel object is of the expected initialization state |
| |
| - The calling thread has sufficient permissions on the object |
| |
| For more details see the "Kernel Objects" section in the documentation. |
| |
| The zephyr build generates an intermediate ELF binary, zephyr_prebuilt.elf, |
| which this script scans looking for kernel objects by examining the DWARF |
| debug information to look for instances of data structures that are considered |
| kernel objects. For device drivers, the API struct pointer populated at build |
| time is also examined to disambiguate between various device driver instances |
| since they are all 'struct device'. |
| |
| This script can generate five different output files: |
| |
| - A gperf script to generate the hash table mapping kernel object memory |
| addresses to kernel object metadata, used to track permissions, |
| object type, initialization state, and any object-specific data. |
| |
| - A header file containing generated macros for validating driver instances |
| inside the system call handlers for the driver subsystem APIs. |
| |
| - A code fragment included by kernel.h with one enum constant for |
| each kernel object type and each driver instance. |
| |
| - The inner cases of a switch/case C statement, included by |
| kernel/userspace.c, mapping the kernel object types and driver |
| instances to their human-readable representation in the |
| otype_to_str() function. |
| |
| - The inner cases of a switch/case C statement, included by |
| kernel/userspace.c, mapping kernel object types to their sizes. |
| This is used for allocating instances of them at runtime |
| (CONFIG_DYNAMIC_OBJECTS) in the obj_size_get() function. |
| """ |
| |
| import sys |
| import argparse |
| import math |
| import os |
| import struct |
| from elf_helper import ElfHelper, kobject_to_enum |
| |
| from collections import OrderedDict |
| |
| # Keys in this dictionary are structs which should be recognized as kernel |
| # objects. Values are a tuple: |
| # |
| # - The first item is None, or the name of a Kconfig that |
| # indicates the presence of this object's definition in case it is not |
| # available in all configurations. |
| # |
| # - The second item is a boolean indicating whether it is permissible for |
| # the object to be located in user-accessible memory. |
| |
| # Regular dictionaries are ordered only with Python 3.6 and |
| # above. Good summary and pointers to official documents at: |
| # https://stackoverflow.com/questions/39980323/are-dictionaries-ordered-in-python-3-6 |
| kobjects = OrderedDict ([ |
| ("k_mem_slab", (None, False)), |
| ("k_msgq", (None, False)), |
| ("k_mutex", (None, False)), |
| ("k_pipe", (None, False)), |
| ("k_queue", (None, False)), |
| ("k_poll_signal", (None, False)), |
| ("k_sem", (None, False)), |
| ("k_stack", (None, False)), |
| ("k_thread", (None, False)), |
| ("k_timer", (None, False)), |
| ("_k_thread_stack_element", (None, False)), |
| ("device", (None, False)), |
| ("sys_mutex", (None, True)), |
| ("k_futex", (None, True)) |
| ]) |
| |
| |
| |
| subsystems = [ |
| "adc_driver_api", |
| "aio_cmp_driver_api", |
| "counter_driver_api", |
| "crypto_driver_api", |
| "dma_driver_api", |
| "flash_driver_api", |
| "gpio_driver_api", |
| "i2c_driver_api", |
| "i2s_driver_api", |
| "ipm_driver_api", |
| "led_driver_api", |
| "pinmux_driver_api", |
| "pwm_driver_api", |
| "entropy_driver_api", |
| "rtc_driver_api", |
| "sensor_driver_api", |
| "spi_driver_api", |
| "uart_driver_api", |
| "can_driver_api", |
| "ptp_clock_driver_api", |
| ] |
| |
| |
| header = """%compare-lengths |
| %define lookup-function-name z_object_lookup |
| %language=ANSI-C |
| %global-table |
| %struct-type |
| %{ |
| #include <kernel.h> |
| #include <toolchain.h> |
| #include <syscall_handler.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 *z_object_gperf_find(void *obj) |
| { |
| return z_object_lookup((const char *)obj, sizeof(void *)); |
| } |
| |
| void z_object_gperf_wordlist_foreach(_wordlist_cb_func_t func, void *context) |
| { |
| int i; |
| |
| for (i = MIN_HASH_VALUE; i <= MAX_HASH_VALUE; i++) { |
| if (wordlist[i].name != NULL) { |
| func(&wordlist[i], context); |
| } |
| } |
| } |
| |
| #ifndef CONFIG_DYNAMIC_OBJECTS |
| struct _k_object *z_object_find(void *obj) |
| ALIAS_OF(z_object_gperf_find); |
| |
| void z_object_wordlist_foreach(_wordlist_cb_func_t func, void *context) |
| ALIAS_OF(z_object_gperf_wordlist_foreach); |
| #endif |
| """ |
| |
| |
| def write_gperf_table(fp, eh, objs, static_begin, static_end): |
| fp.write(header) |
| num_mutexes = eh.get_sys_mutex_counter() |
| if num_mutexes != 0: |
| fp.write("static struct k_mutex kernel_mutexes[%d] = {\n" % num_mutexes) |
| for i in range(num_mutexes): |
| fp.write("_K_MUTEX_INITIALIZER(kernel_mutexes[%d])" % i) |
| if i != num_mutexes - 1: |
| fp.write(", ") |
| fp.write("};\n") |
| |
| num_futex = eh.get_futex_counter() |
| if (num_futex != 0): |
| fp.write("static struct z_futex_data futex_data[%d] = {\n" % num_futex) |
| for i in range(num_futex): |
| fp.write("Z_FUTEX_DATA_INITIALIZER(futex_data[%d])" % i) |
| if (i != num_futex - 1): |
| fp.write(", ") |
| fp.write("};\n") |
| |
| fp.write("%%\n") |
| # Setup variables for mapping thread indexes |
| syms = eh.get_symbols() |
| thread_max_bytes = syms["CONFIG_MAX_THREAD_BYTES"] |
| thread_idx_map = {} |
| |
| for i in range(0, thread_max_bytes): |
| thread_idx_map[i] = 0xFF |
| |
| for obj_addr, ko in objs.items(): |
| obj_type = ko.type_name |
| # 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 eh.little_endian else ">I", obj_addr) |
| fp.write("\"") |
| for byte in byte_str: |
| val = "\\x%02x" % byte |
| fp.write(val) |
| |
| fp.write( |
| "\",{},%s,%s,%s\n" % |
| (obj_type, |
| "K_OBJ_FLAG_INITIALIZED" if initialized else "0", |
| str(ko.data))) |
| |
| if obj_type == "K_OBJ_THREAD": |
| idx = math.floor(ko.data / 8) |
| bit = ko.data % 8 |
| thread_idx_map[idx] = thread_idx_map[idx] & ~(2**bit) |
| |
| fp.write(footer) |
| |
| # Generate the array of already mapped thread indexes |
| fp.write('\n') |
| fp.write('u8_t _thread_idx_map[%d] = {' % (thread_max_bytes)) |
| |
| for i in range(0, thread_max_bytes): |
| fp.write(' 0x%x, ' % (thread_idx_map[i])) |
| |
| fp.write('};\n') |
| |
| |
| driver_macro_tpl = """ |
| #define Z_SYSCALL_DRIVER_%(driver_upper)s(ptr, op) Z_SYSCALL_DRIVER_GEN(ptr, op, %(driver_lower)s, %(driver_upper)s) |
| """ |
| |
| |
| def write_validation_output(fp): |
| fp.write("#ifndef DRIVER_VALIDATION_GEN_H\n") |
| fp.write("#define DRIVER_VALIDATION_GEN_H\n") |
| |
| fp.write("""#define Z_SYSCALL_DRIVER_GEN(ptr, op, driver_lower_case, driver_upper_case) \\ |
| (Z_SYSCALL_OBJ(ptr, K_OBJ_DRIVER_##driver_upper_case) || \\ |
| Z_SYSCALL_DRIVER_OP(ptr, driver_lower_case##_driver_api, op)) |
| """) |
| |
| for subsystem in subsystems: |
| subsystem = subsystem.replace("_driver_api", "") |
| |
| fp.write(driver_macro_tpl % { |
| "driver_lower": subsystem.lower(), |
| "driver_upper": subsystem.upper(), |
| }) |
| |
| fp.write("#endif /* DRIVER_VALIDATION_GEN_H */\n") |
| |
| |
| def write_kobj_types_output(fp): |
| fp.write("/* Core kernel objects */\n") |
| for kobj, obj_info in kobjects.items(): |
| dep, _ = obj_info |
| if kobj == "device": |
| continue |
| |
| if dep: |
| fp.write("#ifdef %s\n" % dep) |
| |
| fp.write("%s,\n" % kobject_to_enum(kobj)) |
| |
| if dep: |
| fp.write("#endif\n") |
| |
| fp.write("/* Driver subsystems */\n") |
| for subsystem in subsystems: |
| subsystem = subsystem.replace("_driver_api", "").upper() |
| fp.write("K_OBJ_DRIVER_%s,\n" % subsystem) |
| |
| |
| def write_kobj_otype_output(fp): |
| fp.write("/* Core kernel objects */\n") |
| for kobj, obj_info in kobjects.items(): |
| dep, _ = obj_info |
| if kobj == "device": |
| continue |
| |
| if dep: |
| fp.write("#ifdef %s\n" % dep) |
| |
| fp.write('case %s: ret = "%s"; break;\n' % |
| (kobject_to_enum(kobj), kobj)) |
| if dep: |
| fp.write("#endif\n") |
| |
| fp.write("/* Driver subsystems */\n") |
| for subsystem in subsystems: |
| subsystem = subsystem.replace("_driver_api", "") |
| fp.write('case K_OBJ_DRIVER_%s: ret = "%s driver"; break;\n' % ( |
| subsystem.upper(), |
| subsystem |
| )) |
| |
| |
| def write_kobj_size_output(fp): |
| fp.write("/* Non device/stack objects */\n") |
| for kobj, obj_info in kobjects.items(): |
| dep, _ = obj_info |
| # device handled by default case. Stacks are not currently handled, |
| # if they eventually are it will be a special case. |
| if kobj == "device" or kobj == "_k_thread_stack_element": |
| continue |
| |
| if dep: |
| fp.write("#ifdef %s\n" % dep) |
| |
| fp.write('case %s: ret = sizeof(struct %s); break;\n' % |
| (kobject_to_enum(kobj), kobj)) |
| if dep: |
| fp.write("#endif\n") |
| |
| |
| def parse_args(): |
| global args |
| |
| parser = argparse.ArgumentParser( |
| description=__doc__, |
| formatter_class=argparse.RawDescriptionHelpFormatter) |
| |
| parser.add_argument("-k", "--kernel", required=False, |
| help="Input zephyr ELF binary") |
| parser.add_argument( |
| "-g", "--gperf-output", required=False, |
| help="Output list of kernel object addresses for gperf use") |
| parser.add_argument( |
| "-V", "--validation-output", required=False, |
| help="Output driver validation macros") |
| parser.add_argument( |
| "-K", "--kobj-types-output", required=False, |
| help="Output k_object enum constants") |
| parser.add_argument( |
| "-S", "--kobj-otype-output", required=False, |
| help="Output case statements for otype_to_str()") |
| parser.add_argument( |
| "-Z", "--kobj-size-output", required=False, |
| help="Output case statements for obj_size_get()") |
| parser.add_argument("-v", "--verbose", action="store_true", |
| help="Print extra debugging information") |
| args = parser.parse_args() |
| if "VERBOSE" in os.environ: |
| args.verbose = 1 |
| |
| |
| def main(): |
| parse_args() |
| |
| if args.gperf_output: |
| assert args.kernel, "--kernel ELF required for --gperf-output" |
| eh = ElfHelper(args.kernel, args.verbose, kobjects, subsystems) |
| syms = eh.get_symbols() |
| max_threads = syms["CONFIG_MAX_THREAD_BYTES"] * 8 |
| objs = eh.find_kobjects(syms) |
| if not objs: |
| sys.stderr.write("WARNING: zero kobject found in %s\n" |
| % args.kernel) |
| |
| thread_counter = eh.get_thread_counter() |
| if thread_counter > max_threads: |
| sys.stderr.write("Too many thread objects (%d)\n" % thread_counter) |
| sys.stderr.write("Increase CONFIG_MAX_THREAD_BYTES to %d\n" % |
| -(-thread_counter // 8)) |
| sys.exit(1) |
| |
| with open(args.gperf_output, "w") as fp: |
| write_gperf_table(fp, eh, objs, |
| syms["_static_kernel_objects_begin"], |
| syms["_static_kernel_objects_end"]) |
| |
| if args.validation_output: |
| with open(args.validation_output, "w") as fp: |
| write_validation_output(fp) |
| |
| if args.kobj_types_output: |
| with open(args.kobj_types_output, "w") as fp: |
| write_kobj_types_output(fp) |
| |
| if args.kobj_otype_output: |
| with open(args.kobj_otype_output, "w") as fp: |
| write_kobj_otype_output(fp) |
| |
| if args.kobj_size_output: |
| with open(args.kobj_size_output, "w") as fp: |
| write_kobj_size_output(fp) |
| |
| |
| if __name__ == "__main__": |
| main() |
