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authorPeter Griffin <peter.griffin@linaro.org>2017-07-12 14:34:13 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-12 16:26:00 -0700
commit821f74402a4c67de63cb6bab5bae7c7a3b298ac2 (patch)
treefcd6b0920d7de0d5d0e1975083696ae259d2cf40 /scripts/gdb/linux/proc.py
parent59224ac1cf9cacf76a82266854921ca6c9887f20 (diff)
download96b-common-821f74402a4c67de63cb6bab5bae7c7a3b298ac2.tar.gz
scripts/gdb: add lx-fdtdump command
lx-fdtdump dumps the flattened device tree passed to the kernel from the bootloader to the filename specified as the command argument. If no argument is provided it defaults to fdtdump.dtb. This then allows further post processing on the machine running GDB. The fdt header is also also printed in the GDB console. For example: (gdb) lx-fdtdump fdt_magic: 0xD00DFEED fdt_totalsize: 0xC108 off_dt_struct: 0x38 off_dt_strings: 0x3804 off_mem_rsvmap: 0x28 version: 17 last_comp_version: 16 Dumped fdt to fdtdump.dtb >fdtdump fdtdump.dtb | less This command is useful as the bootloader can often re-write parts of the device tree, and this can sometimes cause the kernel to not boot. Link: http://lkml.kernel.org/r/1481280065-5336-2-git-send-email-kbingham@kernel.org Signed-off-by: Peter Griffin <peter.griffin@linaro.org> Signed-off-by: Kieran Bingham <kbingham@kernel.org> Cc: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'scripts/gdb/linux/proc.py')
-rw-r--r--scripts/gdb/linux/proc.py73
1 files changed, 73 insertions, 0 deletions
diff --git a/scripts/gdb/linux/proc.py b/scripts/gdb/linux/proc.py
index 38b1f09d1cd9..086d27223c0c 100644
--- a/scripts/gdb/linux/proc.py
+++ b/scripts/gdb/linux/proc.py
@@ -16,6 +16,7 @@ from linux import constants
from linux import utils
from linux import tasks
from linux import lists
+from struct import *
class LxCmdLine(gdb.Command):
@@ -195,3 +196,75 @@ values of that process namespace"""
info_opts(MNT_INFO, m_flags)))
LxMounts()
+
+
+class LxFdtDump(gdb.Command):
+ """Output Flattened Device Tree header and dump FDT blob to the filename
+ specified as the command argument. Equivalent to
+ 'cat /proc/fdt > fdtdump.dtb' on a running target"""
+
+ def __init__(self):
+ super(LxFdtDump, self).__init__("lx-fdtdump", gdb.COMMAND_DATA,
+ gdb.COMPLETE_FILENAME)
+
+ def fdthdr_to_cpu(self, fdt_header):
+
+ fdt_header_be = ">IIIIIII"
+ fdt_header_le = "<IIIIIII"
+
+ if utils.get_target_endianness() == 1:
+ output_fmt = fdt_header_le
+ else:
+ output_fmt = fdt_header_be
+
+ return unpack(output_fmt, pack(fdt_header_be,
+ fdt_header['magic'],
+ fdt_header['totalsize'],
+ fdt_header['off_dt_struct'],
+ fdt_header['off_dt_strings'],
+ fdt_header['off_mem_rsvmap'],
+ fdt_header['version'],
+ fdt_header['last_comp_version']))
+
+ def invoke(self, arg, from_tty):
+
+ if not constants.LX_CONFIG_OF:
+ raise gdb.GdbError("Kernel not compiled with CONFIG_OF\n")
+
+ if len(arg) == 0:
+ filename = "fdtdump.dtb"
+ else:
+ filename = arg
+
+ py_fdt_header_ptr = gdb.parse_and_eval(
+ "(const struct fdt_header *) initial_boot_params")
+ py_fdt_header = py_fdt_header_ptr.dereference()
+
+ fdt_header = self.fdthdr_to_cpu(py_fdt_header)
+
+ if fdt_header[0] != constants.LX_OF_DT_HEADER:
+ raise gdb.GdbError("No flattened device tree magic found\n")
+
+ gdb.write("fdt_magic: 0x{:02X}\n".format(fdt_header[0]))
+ gdb.write("fdt_totalsize: 0x{:02X}\n".format(fdt_header[1]))
+ gdb.write("off_dt_struct: 0x{:02X}\n".format(fdt_header[2]))
+ gdb.write("off_dt_strings: 0x{:02X}\n".format(fdt_header[3]))
+ gdb.write("off_mem_rsvmap: 0x{:02X}\n".format(fdt_header[4]))
+ gdb.write("version: {}\n".format(fdt_header[5]))
+ gdb.write("last_comp_version: {}\n".format(fdt_header[6]))
+
+ inf = gdb.inferiors()[0]
+ fdt_buf = utils.read_memoryview(inf, py_fdt_header_ptr,
+ fdt_header[1]).tobytes()
+
+ try:
+ f = open(filename, 'wb')
+ except:
+ raise gdb.GdbError("Could not open file to dump fdt")
+
+ f.write(fdt_buf)
+ f.close()
+
+ gdb.write("Dumped fdt blob to " + filename + "\n")
+
+LxFdtDump()