diff options
Diffstat (limited to 'util/cbmem/cbmem.py')
| -rwxr-xr-x | util/cbmem/cbmem.py | 267 |
1 files changed, 158 insertions, 109 deletions
diff --git a/util/cbmem/cbmem.py b/util/cbmem/cbmem.py index 3e8476dbec..f4f3e887e7 100755 --- a/util/cbmem/cbmem.py +++ b/util/cbmem/cbmem.py @@ -33,29 +33,46 @@ console sections. ''' import mmap -import re import struct import sys -import time -# These definitions follow src/include/cbmem.h -CBMEM_MAGIC = 0x434f5245 -CBMEM_MAX_ENTRIES = 16 +def get_phys_mem(addr, size): + '''Read size bytes from address addr by mmaping /dev/mem''' -CBMEM_ENTRY_FORMAT = '@LLQQ' -CONSOLE_HEADER_FORMAT = '@LL' -TIMESTAMP_HEADER_FORMAT = '@QLL' -TIMESTAMP_ENTRY_FORMAT = '@LQ' - -mf_fileno = 0 # File number of the file providing access to memory. - -def align_up(base, alignment): - '''Increment to the alignment boundary. - - Return the next integer larger than 'base' and divisible by 'alignment'. - ''' - - return base + alignment - base % alignment + mf = open("/dev/mem") + delta = addr % 4096 + mm = mmap.mmap(mf.fileno(), size + delta, + mmap.MAP_PRIVATE, offset=(addr - delta)) + buf = mm.read(size + delta) + mf.close() + return buf[delta:] + +# This class and metaclass make it easier to define and access structures +# which live in physical memory. To use them, inherit from CStruct and define +# a class member called struct_members which is a tuple of pairs. The first +# item in the pair is the type format specifier that should be used with +# struct.unpack to read that member from memory. The second item is the name +# that member should have in the resulting object. + +class MetaCStruct(type): + def __init__(cls, name, bases, dct): + struct_members = dct["struct_members"] + cls.struct_fmt = "@" + for char, name in struct_members: + cls.struct_fmt += char + cls.struct_len = struct.calcsize(cls.struct_fmt) + super(MetaCStruct, cls).__init__(name, bases, dct) + +class CStruct(object): + __metaclass__ = MetaCStruct + struct_members = () + + def __init__(self, addr): + self.raw_memory = get_phys_mem(addr, self.struct_len) + values = struct.unpack(self.struct_fmt, self.raw_memory) + names = (name for char, name in self.struct_members) + for name, value in zip(names, values): + setattr(self, name, value) def normalize_timer(value, freq): '''Convert timer reading into microseconds. @@ -96,109 +113,141 @@ def get_cpu_freq(): # Convert reading into Hertz return float(freq_str) * 1000.0 -def get_mem_size(): - '''Retrieve amount of memory available to the CPU from /proc/meminfo.''' - mult = { - 'kB': 1024 - } - meminfo = open('/proc/meminfo').read() - m = re.search('MemTotal:.*\n', meminfo) - mem_string = re.search('MemTotal:.*\n', meminfo).group(0) - (_, size, mult_name) = mem_string.split() - return int(size) * mult[mult_name] - -def parse_mem_at(addr, format): - '''Read and parse a memory location. - - This function reads memory at the passed in address, parses it according - to the passed in format specification and returns a list of values. - - The first value in the list is the size of data matching the format - expression, and the rest of the elements of the list are the actual values - retrieved using the format. - ''' - - size = struct.calcsize(format) - delta = addr % 4096 # mmap requires the offset to be page size aligned. - mm = mmap.mmap(mf_fileno, size + delta, - mmap.MAP_PRIVATE, offset=(addr - delta)) - buf = mm.read(size + delta) - mm.close() - rv = [size,] + list(struct.unpack(format, buf[delta:size + delta + 1])) - return rv - -def dprint(text): - '''Debug print function. - - Edit it to get the debug output. - ''' - - if False: - print text - def process_timers(base): '''Scan the array of timestamps found in CBMEM at address base. For each timestamp print the timer ID and the value in microseconds. ''' - (step, base_time, max_entr, entr) = parse_mem_at( - base, TIMESTAMP_HEADER_FORMAT) - - print('\ntime base %d, total entries %d' % (base_time, entr)) + class TimestampHeader(CStruct): + struct_members = ( + ("Q", "base_time"), + ("L", "max_entr"), + ("L", "entr") + ) + + class TimestampEntry(CStruct): + struct_members = ( + ("L", "timer_id"), + ("Q", "timer_value") + ) + + header = TimestampHeader(base) + print('\ntime base %d, total entries %d' % (header.base_time, header.entr)) clock_freq = get_cpu_freq() - base = base + step - for i in range(entr): - (step, timer_id, timer_value) = parse_mem_at( - base, TIMESTAMP_ENTRY_FORMAT) - print '%d:%s ' % (timer_id, normalize_timer(timer_value, clock_freq)), - base = base + step + base = base + header.struct_len + for i in range(header.entr): + timestamp = TimestampEntry(base) + print '%d:%s ' % (timestamp.timer_id, + normalize_timer(timestamp.timer_value, clock_freq)), + base = base + timestamp.struct_len print def process_console(base): '''Dump the console log buffer contents found at address base.''' - (step, size, cursor) = parse_mem_at(base, CONSOLE_HEADER_FORMAT) - print 'cursor at %d\n' % cursor + class ConsoleHeader(CStruct): + struct_members = ( + ("L", "size"), + ("L", "cursor") + ) - cons_string_format = '%ds' % min(cursor, size) - (_, cons_text) = parse_mem_at(base + step, cons_string_format) + header = ConsoleHeader(base) + print 'cursor at %d\n' % header.cursor + + cons_addr = base + header.struct_len + cons_length = min(header.cursor, header.size) + cons_text = get_phys_mem(cons_addr, cons_length) print cons_text print '\n' -mem_alignment = 1024 * 1024 * 1024 # 1 GBytes -table_alignment = 128 * 1024 - -mem_size = get_mem_size() - -# start at memory address aligned at 128K. -offset = align_up(mem_size, table_alignment) - -dprint('mem_size %x offset %x' %(mem_size, offset)) -mf = open("/dev/mem") -mf_fileno = mf.fileno() - -while offset % mem_alignment: # do not cross the 1G boundary while searching - (step, magic, mid, base, size) = parse_mem_at(offset, CBMEM_ENTRY_FORMAT) - if magic == CBMEM_MAGIC: - offset = offset + step - break - offset += table_alignment -else: - print 'Did not find the CBMEM' - sys.exit(0) - -for i in (range(1, CBMEM_MAX_ENTRIES)): - (_, magic, mid, base, size) = parse_mem_at(offset, CBMEM_ENTRY_FORMAT) - if mid == 0: - break - - print '%x, %x, %x' % (mid, base, size) - if mid == 0x54494d45: - process_timers(base) - if mid == 0x434f4e53: - process_console(base) - - offset = offset + step - -mf.close() +def ipchksum(buf): + '''Checksumming function used on the coreboot tables. The buffer being + checksummed is summed up as if it was an array of 16 bit unsigned + integers. If there are an odd number of bytes, the last element is zero + extended.''' + + size = len(buf) + odd = size % 2 + fmt = "<%dH" % ((size - odd) / 2) + if odd: + fmt += "B" + shorts = struct.unpack(fmt, buf) + checksum = sum(shorts) + checksum = (checksum >> 16) + (checksum & 0xffff) + checksum += (checksum >> 16) + checksum = ~checksum & 0xffff + return checksum + +def parse_tables(base, length): + '''Find the coreboot tables in memory and process whatever we can.''' + + class CBTableHeader(CStruct): + struct_members = ( + ("4s", "signature"), + ("I", "header_bytes"), + ("I", "header_checksum"), + ("I", "table_bytes"), + ("I", "table_checksum"), + ("I", "table_entries") + ) + + class CBTableEntry(CStruct): + struct_members = ( + ("I", "tag"), + ("I", "size") + ) + + class CBTableForward(CBTableEntry): + struct_members = CBTableEntry.struct_members + ( + ("Q", "forward"), + ) + + class CBMemTab(CBTableEntry): + struct_members = CBTableEntry.struct_members + ( + ("L", "cbmem_tab"), + ) + + for addr in range(base, base + length, 16): + header = CBTableHeader(addr) + if header.signature == "LBIO": + break + else: + return -1 + + if header.header_bytes == 0: + return -1 + + if ipchksum(header.raw_memory) != 0: + print "Bad header checksum" + return -1 + + addr += header.header_bytes + table = get_phys_mem(addr, header.table_bytes) + if ipchksum(table) != header.table_checksum: + print "Bad table checksum" + return -1 + + for i in range(header.table_entries): + entry = CBTableEntry(addr) + if entry.tag == 0x11: # Forwarding entry + return parse_tables(CBTableForward(addr).forward, length) + elif entry.tag == 0x16: # Timestamps + process_timers(CBMemTab(addr).cbmem_tab) + elif entry.tag == 0x17: # CBMEM console + process_console(CBMemTab(addr).cbmem_tab) + + addr += entry.size + + return 0 + +def main(): + for base, length in (0x00000000, 0x1000), (0x000f0000, 0x1000): + if parse_tables(base, length): + break + else: + print "Didn't find the coreboot tables" + return 0 + +if __name__ == "__main__": + sys.exit(main()) |