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348b64ebb0
The j6tw (j6 table walk) command to debug page tables was throwing an exception for an integer that was too big when the default radix was 16, because it would interpret ints as hex even without the 0x prefix. Now j6tw explicitly converts to hex and uses the prefix to be explicit.
138 lines
3.7 KiB
Python
138 lines
3.7 KiB
Python
import gdb
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class PrintStackCommand(gdb.Command):
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def __init__(self):
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super().__init__("j6stack", gdb.COMMAND_DATA)
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def invoke(self, arg, from_tty):
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args = gdb.string_to_argv(arg)
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base = "$rsp"
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if len(args) > 0:
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base = args[0]
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depth = 22
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if len(args) > 1:
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depth = int(args[1])
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for i in range(depth-1, -1, -1):
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try:
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offset = i * 8
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base_addr = gdb.parse_and_eval(base)
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value = gdb.parse_and_eval(f"*(uint64_t*)({base} + 0x{offset:x})")
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print("{:016x} (+{:04x}): {:016x}".format(int(base_addr) + offset, offset, int(value)))
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except Exception as e:
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print(e)
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continue
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class PrintBacktraceCommand(gdb.Command):
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def __init__(self):
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super().__init__("j6bt", gdb.COMMAND_DATA)
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def invoke(self, arg, from_tty):
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args = gdb.string_to_argv(arg)
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depth = 30
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if len(args) > 0:
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depth = int(args[0])
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frame = "$rbp"
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if len(args) > 1:
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frame = args[1]
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frame = gdb.parse_and_eval(f"{frame}")
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for i in range(depth-1, -1, -1):
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ret = gdb.parse_and_eval(f"*(uint64_t*)({frame} + 0x8)")
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name = ""
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try:
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block = gdb.block_for_pc(int(ret))
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if block:
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name = block.function or ""
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except RuntimeError:
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pass
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print("{:016x}: {:016x} {}".format(int(frame), int(ret), name))
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frame = gdb.parse_and_eval(f"*(uint64_t*)({frame})")
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if frame == 0 or ret == 0:
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return
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class TableWalkCommand(gdb.Command):
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def __init__(self):
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super().__init__("j6tw", gdb.COMMAND_DATA)
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def invoke(self, arg, from_tty):
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args = gdb.string_to_argv(arg)
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if len(args) < 2:
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raise Exception("Must be: j6tw <pml4> <addr>")
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pml4 = int(gdb.parse_and_eval(args[0]))
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addr = int(gdb.parse_and_eval(args[1]))
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indices = [
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(addr >> 39) & 0x1ff,
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(addr >> 30) & 0x1ff,
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(addr >> 21) & 0x1ff,
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(addr >> 12) & 0x1ff,
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]
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names = ["PML4", "PDP", "PD", "PT"]
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table_flags = [
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(0x0001, "present"),
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(0x0002, "write"),
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(0x0004, "user"),
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(0x0008, "pwt"),
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(0x0010, "pcd"),
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(0x0020, "accessed"),
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(0x0040, "dirty"),
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(0x0080, "largepage"),
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(0x0100, "global"),
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(0x1080, "pat"),
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((1<<63), "xd"),
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]
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page_flags = [
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(0x0001, "present"),
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(0x0002, "write"),
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(0x0004, "user"),
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(0x0008, "pwt"),
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(0x0010, "pcd"),
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(0x0020, "accessed"),
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(0x0040, "dirty"),
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(0x0080, "pat"),
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(0x0100, "global"),
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((1<<63), "xd"),
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]
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flagsets = [table_flags, table_flags, table_flags, page_flags]
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table = pml4
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entry = 0
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for i in range(len(indices)):
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entry = int(gdb.parse_and_eval(f'((uint64_t*)0x{table:x})[0x{indices[i]:x}]'))
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flagset = flagsets[i]
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flag_names = " | ".join([f[1] for f in flagset if (entry & f[0]) == f[0]])
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print(f"{names[i]:>4}: {table:016x}")
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print(f" index: {indices[i]:3} {entry:016x}")
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print(f" flags: {flag_names}")
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if (entry & 1) == 0 or (i < 3 and (entry & 0x80)):
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break
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table = (entry & 0x7ffffffffffffe00) | 0xffffc00000000000
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PrintStackCommand()
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PrintBacktraceCommand()
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TableWalkCommand()
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gdb.execute("target remote :1234")
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gdb.execute("display/i $rip")
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