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gen_kobject_list.py: device driver support

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Device drivers need to be treated like other kernel objects, with
thread-level permissions and validation of struct device pointers passed
in from userspace when making API calls.

However it's not sufficient to identify an object as a driver, we need
to know what subsystem it belongs to (if any) so that userspace cannot,
for example, make Ethernet driver API calls using a UART driver object.

Upon encountering a variable representing a device struct, we look at
the value of its driver_api member. If that corresponds to an instance
of a driver API struct belonging to a known subsystem, the proper
K_OBJ_DRIVER_* enumeration type will be associated with this device in
the generated gperf table.

If there is no API struct or it doesn't correspond to a known subsystem,
the device is omitted from the table; it's presumably used internally
by the kernel or is a singleton with specific APIs for it that do not
take a struct device parameter.

The list of kobjects and subsystems in the script is simplified since
the enumeration type name is strongly derived from the name of the data
structure.

A device object is marked as initialized after its init function has
been run at boot.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2017-09-27 12:59:28 -07:00 committed by Andrew Boie
parent fa94ee7460
commit 5bd891d3b6
4 changed files with 215 additions and 30 deletions
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28
include/kernel.h
View file

@ -124,7 +124,12 @@ struct k_timer;
struct k_poll_event;
struct k_poll_signal;
/* This enumeration needs to be kept in sync with the lists of kernel objects
* and subsystems in scripts/gen_kobject_list.py, as well as the otype_to_str()
* function in kernel/userspace.c
*/
enum k_objects {
/* Core kernel objects */
K_OBJ_ALERT,
K_OBJ_DELAYED_WORK,
K_OBJ_MEM_SLAB,
@ -138,6 +143,29 @@ enum k_objects {
K_OBJ_WORK,
K_OBJ_WORK_Q,
/* Driver subsystems */
K_OBJ_DRIVER_ADC,
K_OBJ_DRIVER_AIO_CMP,
K_OBJ_DRIVER_CLOCK_CONTROL,
K_OBJ_DRIVER_COUNTER,
K_OBJ_DRIVER_CRYPTO,
K_OBJ_DRIVER_DMA,
K_OBJ_DRIVER_ETH,
K_OBJ_DRIVER_FLASH,
K_OBJ_DRIVER_GPIO,
K_OBJ_DRIVER_I2C,
K_OBJ_DRIVER_I2S,
K_OBJ_DRIVER_IPM,
K_OBJ_DRIVER_PINMUX,
K_OBJ_DRIVER_PWM,
K_OBJ_DRIVER_RANDOM,
K_OBJ_DRIVER_RTC,
K_OBJ_DRIVER_SENSOR,
K_OBJ_DRIVER_SHARED_IRQ,
K_OBJ_DRIVER_SPI,
K_OBJ_DRIVER_UART,
K_OBJ_DRIVER_WDT,
K_OBJ_LAST
};

1
kernel/device.c
View file

@ -52,6 +52,7 @@ void _sys_device_do_config_level(int level)
struct device_config *device = info->config;
device->init(info);
_k_object_init(info);
}
}

45
kernel/userspace.c
View file

@ -33,6 +33,7 @@ const char *otype_to_str(enum k_objects otype)
*/
#ifdef CONFIG_PRINTK
switch (otype) {
/* Core kernel objects */
case K_OBJ_ALERT:
return "k_alert";
case K_OBJ_DELAYED_WORK:
@ -57,6 +58,50 @@ const char *otype_to_str(enum k_objects otype)
return "k_work";
case K_OBJ_WORK_Q:
return "k_work_q";
/* Driver subsystems */
case K_OBJ_DRIVER_ADC:
return "adc driver";
case K_OBJ_DRIVER_AIO_CMP:
return "aio comparator driver";
case K_OBJ_DRIVER_CLOCK_CONTROL:
return "clock control driver";
case K_OBJ_DRIVER_COUNTER:
return "counter driver";
case K_OBJ_DRIVER_CRYPTO:
return "crypto driver";
case K_OBJ_DRIVER_DMA:
return "dma driver";
case K_OBJ_DRIVER_ETH:
return "ethernet driver";
case K_OBJ_DRIVER_FLASH:
return "flash driver";
case K_OBJ_DRIVER_GPIO:
return "gpio driver";
case K_OBJ_DRIVER_I2C:
return "i2c driver";
case K_OBJ_DRIVER_I2S:
return "i2s driver";
case K_OBJ_DRIVER_IPM:
return "ipm driver";
case K_OBJ_DRIVER_PINMUX:
return "pinmux driver";
case K_OBJ_DRIVER_PWM:
return "pwm driver";
case K_OBJ_DRIVER_RANDOM:
return "random driver";
case K_OBJ_DRIVER_RTC:
return "realtime clock driver";
case K_OBJ_DRIVER_SENSOR:
return "sensor driver";
case K_OBJ_DRIVER_SHARED_IRQ:
return "shared irq driver";
case K_OBJ_DRIVER_SPI:
return "spi driver";
case K_OBJ_DRIVER_UART:
return "uart driver";
case K_OBJ_DRIVER_WDT:
return "watchdog timer driver";
default:
return "?";
}

171
scripts/gen_kobject_list.py
View file

@ -20,20 +20,52 @@ if LooseVersion(elftools.__version__) < LooseVersion('0.24'):
sys.stderr.write("pyelftools is out of date, need version 0.24 or later\n")
sys.exit(1)
kobjects = {
"k_alert" : "K_OBJ_ALERT",
"k_delayed_work" : "K_OBJ_DELAYED_WORK",
"k_mem_slab" : "K_OBJ_MEM_SLAB",
"k_msgq" : "K_OBJ_MSGQ",
"k_mutex" : "K_OBJ_MUTEX",
"k_pipe" : "K_OBJ_PIPE",
"k_sem" : "K_OBJ_SEM",
"k_stack" : "K_OBJ_STACK",
"k_thread" : "K_OBJ_THREAD",
"k_timer" : "K_OBJ_TIMER",
"k_work" : "K_OBJ_WORK",
"k_work_q" : "K_OBJ_WORK_Q",
}
kobjects = [
"k_alert",
"k_delayed_work",
"k_mem_slab",
"k_msgq",
"k_mutex",
"k_pipe",
"k_sem",
"k_stack",
"k_thread",
"k_timer",
"k_work",
"k_work_q",
"device"
]
subsystems = [
"adc_driver_api",
"aio_cmp_driver_api",
"clock_control_driver_api",
"counter_driver_api",
"crypto_driver_api",
"dma_driver_api",
"eth_driver_api",
"flash_driver_api",
"gpio_driver_api",
"i2c_driver_api",
"i2s_driver_api",
"ipm_driver_api",
"pinmux_driver_api",
"pwm_driver_api",
"random_driver_api",
"rtc_driver_api",
"sensor_driver_api",
"shared_irq_driver_api",
"spi_driver_api",
"uart_driver_api",
"wdt_driver_api",
]
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
@ -43,7 +75,7 @@ type_env = {}
# --- debug stuff ---
scr = os.path.basename(sys.argv[0])
scr = os.path.basename(sys.argv[0])
def debug(text):
if not args.verbose:
@ -81,10 +113,10 @@ class ArrayType:
def get_kobjects(self, addr):
mt = type_env[self.member_type]
objs = []
objs = {}
for i in range(self.num_members):
objs.extend(mt.get_kobjects(addr + (i * mt.size)))
objs.update(mt.get_kobjects(addr + (i * mt.size)))
return objs
@ -109,6 +141,23 @@ class AggregateTypeMember:
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
@ -140,17 +189,18 @@ class AggregateType:
return result
def get_kobjects(self, addr):
objs = []
objs = {}
for member in self.members:
objs.extend(member.get_kobjects(addr))
objs.update(member.get_kobjects(addr))
return objs
class KobjectType:
def __init__(self, offset, name, size):
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
@ -159,7 +209,7 @@ class KobjectType:
return True
def get_kobjects(self, addr):
return [(addr, kobjects[self.name])]
return {addr: self}
# --- helper functions for getting data from DIEs ---
@ -170,6 +220,9 @@ def die_get_name(die):
def die_get_type_offset(die):
if not 'DW_AT_type' in die.attributes:
return 0
return die.attributes["DW_AT_type"].value + die.cu.cu_offset
@ -188,7 +241,11 @@ def analyze_die_struct(die):
if not size:
return
if name not in kobjects:
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
@ -204,7 +261,13 @@ def analyze_die_struct(die):
return
type_env[offset] = KobjectType(offset, name, size)
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):
@ -231,6 +294,24 @@ def analyze_die_array(die):
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 = section.data()
offset = addr - start
return struct.unpack("<I" if args.little_endian else ">I",
data[offset:offset+4])[0]
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(die.cu).header
files = lp_header["file_entry"]
@ -252,6 +333,8 @@ def find_kobjects(elf, syms):
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()
@ -268,6 +351,8 @@ def find_kobjects(elf, syms):
# 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_variable":
@ -285,7 +370,7 @@ def find_kobjects(elf, syms):
# Step 3: Now that we know all the types we are looking for, examine
# all variables
all_objs = []
all_objs = {}
# Gross hack, see below
work_q_found = False
@ -336,7 +421,8 @@ def find_kobjects(elf, syms):
addr = (loc.value[1] | (loc.value[2] << 8) | (loc.value[3] << 16) |
(loc.value[4] << 24))
if addr < kram_start or addr >= kram_end:
if ((addr < kram_start or addr >= kram_end)
and (addr < krom_start or addr >= krom_end)):
if addr == 0:
# Never linked; gc-sections deleted it
continue
@ -347,13 +433,38 @@ def find_kobjects(elf, syms):
type_obj = type_env[type_offset]
objs = type_obj.get_kobjects(addr)
all_objs.extend(objs)
all_objs.update(objs)
debug("symbol '%s' at %s contains %d object(s)" % (name, hex(addr),
len(objs)))
len(objs)))
debug("found %d kernel object instances total" % len(all_objs))
return all_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.api:
continue
if ko.name != "device":
# Not a device struct so we immediately know its type
ret[addr] = kobject_to_enum(ko.name)
continue
# 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
continue
apiobj = all_objs[apiaddr]
ret[addr] = subsystem_to_enum(apiobj.name)
debug("found %d kernel object instances total" % len(ret))
return ret
header = """%compare-lengths
@ -383,7 +494,7 @@ struct _k_object *_k_object_find(void *obj)
def write_gperf_table(fp, objs, static_begin, static_end):
fp.write(header)
for obj_addr, obj_type in objs:
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