[PATCH 1/2] scripts/gdb: add lx-fdtdump command

[PATCH 1/2] scripts/gdb: add lx-fdtdump command

[Peter Griffin]

lx-fdtdump dumps the flatenned device tree passed to the kernel
from the bootloader to a file called fdtdump.dtb to allow 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.

Signed-off-by: Peter Griffin <peter.griffin-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
 scripts/gdb/linux/constants.py.in |  8 +++++
 scripts/gdb/linux/proc.py         | 70 ++++++++++++++++++++++++++++++++++++++-
 2 files changed, 77 insertions(+), 1 deletion(-)

diff --git a/scripts/gdb/linux/constants.py.in b/scripts/gdb/linux/constants.py.in
index 7986f4e..43c6241 100644
--- a/scripts/gdb/linux/constants.py.in
+++ b/scripts/gdb/linux/constants.py.in
@@ -14,6 +14,7 @@
 
 #include <linux/fs.h>
 #include <linux/mount.h>
+#include <linux/of_fdt.h>
 
 /* We need to stringify expanded macros so that they can be parsed */
 
@@ -50,3 +51,10 @@ LX_VALUE(MNT_NOEXEC)
 LX_VALUE(MNT_NOATIME)
 LX_VALUE(MNT_NODIRATIME)
 LX_VALUE(MNT_RELATIME)
+
+/* linux/of_fdt.h> */
+LX_VALUE(OF_DT_HEADER)
+
+/* Kernel Configs */
+LX_CONFIG(CONFIG_OF)
+
diff --git a/scripts/gdb/linux/proc.py b/scripts/gdb/linux/proc.py
index 38b1f09..f20fcfa 100644
--- a/scripts/gdb/linux/proc.py
+++ b/scripts/gdb/linux/proc.py
@@ -16,7 +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):
     """ Report the Linux Commandline used in the current kernel.
@@ -195,3 +195,71 @@ 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 a file
+       Equivalent to 'cat /proc/fdt > fdtdump.dtb' on a running target"""
+
+    def __init__(self):
+        super(LxFdtDump, self).__init__("lx-fdtdump", gdb.COMMAND_DATA)
+
+    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 constants.LX_CONFIG_OF:
+
+            filename = "fdtdump.dtb"
+
+            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 to " + filename + "\n")
+
+        else:
+            gdb.write("Kernel not compiled with CONFIG_OF\n")
+
+LxFdtDump()
-- 
1.9.1

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[PATCH 2/2] scripts/gdb: fixup some pep8 errors in proc.py

[Peter Griffin]

proc.py:22:1: E302 expected 2 blank lines, found 1
proc.py:200:1: E302 expected 2 blank lines, found 1

Signed-off-by: Peter Griffin <peter.griffin-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
 scripts/gdb/linux/proc.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/scripts/gdb/linux/proc.py b/scripts/gdb/linux/proc.py
index f20fcfa..2d6f74e 100644
--- a/scripts/gdb/linux/proc.py
+++ b/scripts/gdb/linux/proc.py
@@ -18,6 +18,7 @@ from linux import tasks
 from linux import lists
 from struct import *
 
+
 class LxCmdLine(gdb.Command):
     """ Report the Linux Commandline used in the current kernel.
         Equivalent to cat /proc/cmdline on a running target"""
@@ -196,6 +197,7 @@ values of that process namespace"""
 
 LxMounts()
 
+
 class LxFdtDump(gdb.Command):
     """Output Flattened Device Tree header and dump FDT blob to a file
        Equivalent to 'cat /proc/fdt > fdtdump.dtb' on a running target"""
-- 
1.9.1

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Re: [PATCH 2/2] scripts/gdb: fixup some pep8 errors in proc.py

[Kieran Bingham]

Hi Pete,

On 18/10/16 16:07, Peter Griffin wrote:
> proc.py:22:1: E302 expected 2 blank lines, found 1
> proc.py:200:1: E302 expected 2 blank lines, found 1
> 
> Signed-off-by: Peter Griffin <peter.griffin-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> ---
>  scripts/gdb/linux/proc.py | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/scripts/gdb/linux/proc.py b/scripts/gdb/linux/proc.py
> index f20fcfa..2d6f74e 100644
> --- a/scripts/gdb/linux/proc.py
> +++ b/scripts/gdb/linux/proc.py
> @@ -18,6 +18,7 @@ from linux import tasks
>  from linux import lists
>  from struct import *
>  
> +

This was added by patch 1, and can be squashed there.

>  class LxCmdLine(gdb.Command):
>      """ Report the Linux Commandline used in the current kernel.
>          Equivalent to cat /proc/cmdline on a running target"""
> @@ -196,6 +197,7 @@ values of that process namespace"""
>  
>  LxMounts()
>  
> +

Likewise...

>  class LxFdtDump(gdb.Command):
>      """Output Flattened Device Tree header and dump FDT blob to a file
>         Equivalent to 'cat /proc/fdt > fdtdump.dtb' on a running target"""
> 

-- 
Regards

Kieran Bingham
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Re: [PATCH 2/2] scripts/gdb: fixup some pep8 errors in proc.py

[Peter Griffin]

Hi Kieran,

On Tue, 18 Oct 2016, Kieran Bingham wrote:

> Hi Pete,
> 
> On 18/10/16 16:07, Peter Griffin wrote:
> > proc.py:22:1: E302 expected 2 blank lines, found 1
> > proc.py:200:1: E302 expected 2 blank lines, found 1
> > 
> > Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
> > ---
> >  scripts/gdb/linux/proc.py | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/scripts/gdb/linux/proc.py b/scripts/gdb/linux/proc.py
> > index f20fcfa..2d6f74e 100644
> > --- a/scripts/gdb/linux/proc.py
> > +++ b/scripts/gdb/linux/proc.py
> > @@ -18,6 +18,7 @@ from linux import tasks
> >  from linux import lists
> >  from struct import *
> >  
> > +
> 
> This was added by patch 1, and can be squashed there.

Doh, I had deliberately done it as a separate commit, as I thought it was
a pre-existing pep8 error.

Will squash in v2.

regards,

Peter.

Re: [PATCH 1/2] scripts/gdb: add lx-fdtdump command

[Kieran Bingham]

Hi Pete,

Thanks for your patch.

On 18/10/16 16:07, Peter Griffin wrote:
> lx-fdtdump dumps the flatenned device tree passed to the kernel

s/flatenned/flattened/

> from the bootloader to a file called fdtdump.dtb to allow further
> post processing on the machine running GDB. The fdt header is also
> also printed in the GDB console. For example:
> 

Excellent - I've been looking forward to this

General comment: It would be good to see the output filename
configurable as a parameter, defaulting to fdtdump.dtb if none provided.

Is this something you have time to add?

> (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.
> 
> Signed-off-by: Peter Griffin <peter.griffin-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> ---
>  scripts/gdb/linux/constants.py.in |  8 +++++
>  scripts/gdb/linux/proc.py         | 70 ++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 77 insertions(+), 1 deletion(-)
> 
> diff --git a/scripts/gdb/linux/constants.py.in b/scripts/gdb/linux/constants.py.in
> index 7986f4e..43c6241 100644
> --- a/scripts/gdb/linux/constants.py.in
> +++ b/scripts/gdb/linux/constants.py.in
> @@ -14,6 +14,7 @@
>  
>  #include <linux/fs.h>
>  #include <linux/mount.h>
> +#include <linux/of_fdt.h>
>  
>  /* We need to stringify expanded macros so that they can be parsed */
>  
> @@ -50,3 +51,10 @@ LX_VALUE(MNT_NOEXEC)
>  LX_VALUE(MNT_NOATIME)
>  LX_VALUE(MNT_NODIRATIME)
>  LX_VALUE(MNT_RELATIME)
> +
> +/* linux/of_fdt.h> */
> +LX_VALUE(OF_DT_HEADER)
> +
> +/* Kernel Configs */
> +LX_CONFIG(CONFIG_OF)
> +
> diff --git a/scripts/gdb/linux/proc.py b/scripts/gdb/linux/proc.py
> index 38b1f09..f20fcfa 100644
> --- a/scripts/gdb/linux/proc.py
> +++ b/scripts/gdb/linux/proc.py
> @@ -16,7 +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):
>      """ Report the Linux Commandline used in the current kernel.
> @@ -195,3 +195,71 @@ 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 a file
> +       Equivalent to 'cat /proc/fdt > fdtdump.dtb' on a running target"""
> +
> +    def __init__(self):
> +        super(LxFdtDump, self).__init__("lx-fdtdump", gdb.COMMAND_DATA)
> +
> +    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 constants.LX_CONFIG_OF:
> +
> +            filename = "fdtdump.dtb"
> +

You could parse the arguments here to allow users to write to their own
file / path ... arg is just a string, so you can either parse it as such
or convert to argv with
	argv = gdb.string_to_argv(arg)


Aha - I see Jan beat me to it :)


> +            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 to " + filename + "\n")
> +
> +        else:
> +            gdb.write("Kernel not compiled with CONFIG_OF\n")

Would it be cleaner to write
  if not constants.LX_CONFIG_OF:
      raise gdb.GdbError("Kernel not compiled with CONFIG_OF\n")

at the beginning, and reduce the indentation level required ?

> +
> +LxFdtDump()
> 

-- 
Regards

Kieran Bingham
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Re: [PATCH 1/2] scripts/gdb: add lx-fdtdump command

[Peter Griffin]

Hi Kieran,

Thanks for reviewing.

On Tue, 18 Oct 2016, Kieran Bingham wrote:

> Hi Pete,
> 
> Thanks for your patch.
> 
> On 18/10/16 16:07, Peter Griffin wrote:
> > lx-fdtdump dumps the flatenned device tree passed to the kernel
> 
> s/flatenned/flattened/
> 
> > from the bootloader to a file called fdtdump.dtb to allow further
> > post processing on the machine running GDB. The fdt header is also
> > also printed in the GDB console. For example:
> > 
> 
> Excellent - I've been looking forward to this
> 
> General comment: It would be good to see the output filename
> configurable as a parameter, defaulting to fdtdump.dtb if none provided.
> 
> Is this something you have time to add?

Have added this in v2 :)

> 
> > (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.
> > 
> > Signed-off-by: Peter Griffin <peter.griffin-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> > ---
> >  scripts/gdb/linux/constants.py.in |  8 +++++
> >  scripts/gdb/linux/proc.py         | 70 ++++++++++++++++++++++++++++++++++++++-
> >  2 files changed, 77 insertions(+), 1 deletion(-)
> > 
> > diff --git a/scripts/gdb/linux/constants.py.in b/scripts/gdb/linux/constants.py.in
> > index 7986f4e..43c6241 100644
> > --- a/scripts/gdb/linux/constants.py.in
> > +++ b/scripts/gdb/linux/constants.py.in
> > @@ -14,6 +14,7 @@
> >  
> >  #include <linux/fs.h>
> >  #include <linux/mount.h>
> > +#include <linux/of_fdt.h>
> >  
> >  /* We need to stringify expanded macros so that they can be parsed */
> >  
> > @@ -50,3 +51,10 @@ LX_VALUE(MNT_NOEXEC)
> >  LX_VALUE(MNT_NOATIME)
> >  LX_VALUE(MNT_NODIRATIME)
> >  LX_VALUE(MNT_RELATIME)
> > +
> > +/* linux/of_fdt.h> */
> > +LX_VALUE(OF_DT_HEADER)
> > +
> > +/* Kernel Configs */
> > +LX_CONFIG(CONFIG_OF)
> > +
> > diff --git a/scripts/gdb/linux/proc.py b/scripts/gdb/linux/proc.py
> > index 38b1f09..f20fcfa 100644
> > --- a/scripts/gdb/linux/proc.py
> > +++ b/scripts/gdb/linux/proc.py
> > @@ -16,7 +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):
> >      """ Report the Linux Commandline used in the current kernel.
> > @@ -195,3 +195,71 @@ 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 a file
> > +       Equivalent to 'cat /proc/fdt > fdtdump.dtb' on a running target"""
> > +
> > +    def __init__(self):
> > +        super(LxFdtDump, self).__init__("lx-fdtdump", gdb.COMMAND_DATA)
> > +
> > +    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 constants.LX_CONFIG_OF:
> > +
> > +            filename = "fdtdump.dtb"
> > +
> 
> You could parse the arguments here to allow users to write to their own
> file / path ... arg is just a string, so you can either parse it as such
> or convert to argv with
> 	argv = gdb.string_to_argv(arg)
> 
> 
> Aha - I see Jan beat me to it :)
> 
> 
> > +            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 to " + filename + "\n")
> > +
> > +        else:
> > +            gdb.write("Kernel not compiled with CONFIG_OF\n")
> 
> Would it be cleaner to write
>   if not constants.LX_CONFIG_OF:
>       raise gdb.GdbError("Kernel not compiled with CONFIG_OF\n")
> 
> at the beginning, and reduce the indentation level required ?

Good idea, have updated like you suggest in V2 and reduced the
indentation.

regards,

Peter
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Re: [PATCH 1/2] scripts/gdb: add lx-fdtdump command

[Jan Kiszka]

On 2016-10-18 17:07, Peter Griffin wrote:
> lx-fdtdump dumps the flatenned device tree passed to the kernel
> from the bootloader to a file called fdtdump.dtb to allow 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.
> 
> Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
> ---
>  scripts/gdb/linux/constants.py.in |  8 +++++
>  scripts/gdb/linux/proc.py         | 70 ++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 77 insertions(+), 1 deletion(-)
> 
> diff --git a/scripts/gdb/linux/constants.py.in b/scripts/gdb/linux/constants.py.in
> index 7986f4e..43c6241 100644
> --- a/scripts/gdb/linux/constants.py.in
> +++ b/scripts/gdb/linux/constants.py.in
> @@ -14,6 +14,7 @@
>  
>  #include <linux/fs.h>
>  #include <linux/mount.h>
> +#include <linux/of_fdt.h>
>  
>  /* We need to stringify expanded macros so that they can be parsed */
>  
> @@ -50,3 +51,10 @@ LX_VALUE(MNT_NOEXEC)
>  LX_VALUE(MNT_NOATIME)
>  LX_VALUE(MNT_NODIRATIME)
>  LX_VALUE(MNT_RELATIME)
> +
> +/* linux/of_fdt.h> */
> +LX_VALUE(OF_DT_HEADER)
> +
> +/* Kernel Configs */
> +LX_CONFIG(CONFIG_OF)
> +
> diff --git a/scripts/gdb/linux/proc.py b/scripts/gdb/linux/proc.py
> index 38b1f09..f20fcfa 100644
> --- a/scripts/gdb/linux/proc.py
> +++ b/scripts/gdb/linux/proc.py
> @@ -16,7 +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):
>      """ Report the Linux Commandline used in the current kernel.
> @@ -195,3 +195,71 @@ 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 a file
> +       Equivalent to 'cat /proc/fdt > fdtdump.dtb' on a running target"""
> +
> +    def __init__(self):
> +        super(LxFdtDump, self).__init__("lx-fdtdump", gdb.COMMAND_DATA)
> +
> +    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 constants.LX_CONFIG_OF:
> +
> +            filename = "fdtdump.dtb"

Why not specifying the file name as argument? Safer than silently
overwriting potentially pre-existing files or failing without
alternatives if the current directory is not writable.

> +
> +            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 to " + filename + "\n")
> +
> +        else:
> +            gdb.write("Kernel not compiled with CONFIG_OF\n")
> +
> +LxFdtDump()
> 

Jan

-- 
Siemens AG, Corporate Technology, CT RDA ITP SES-DE
Corporate Competence Center Embedded Linux

Re: [PATCH 1/2] scripts/gdb: add lx-fdtdump command

[Peter Griffin]

Hi Jan,

On Tue, 18 Oct 2016, Jan Kiszka wrote:

> On 2016-10-18 17:07, Peter Griffin wrote:
> > lx-fdtdump dumps the flatenned device tree passed to the kernel
> > from the bootloader to a file called fdtdump.dtb to allow 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.
> > 
> > Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
> > ---
> >  scripts/gdb/linux/constants.py.in |  8 +++++
> >  scripts/gdb/linux/proc.py         | 70 ++++++++++++++++++++++++++++++++++++++-
> >  2 files changed, 77 insertions(+), 1 deletion(-)
> > 
> > diff --git a/scripts/gdb/linux/constants.py.in b/scripts/gdb/linux/constants.py.in
> > index 7986f4e..43c6241 100644
> > --- a/scripts/gdb/linux/constants.py.in
> > +++ b/scripts/gdb/linux/constants.py.in
> > @@ -14,6 +14,7 @@
> >  
> >  #include <linux/fs.h>
> >  #include <linux/mount.h>
> > +#include <linux/of_fdt.h>
> >  
> >  /* We need to stringify expanded macros so that they can be parsed */
> >  
> > @@ -50,3 +51,10 @@ LX_VALUE(MNT_NOEXEC)
> >  LX_VALUE(MNT_NOATIME)
> >  LX_VALUE(MNT_NODIRATIME)
> >  LX_VALUE(MNT_RELATIME)
> > +
> > +/* linux/of_fdt.h> */
> > +LX_VALUE(OF_DT_HEADER)
> > +
> > +/* Kernel Configs */
> > +LX_CONFIG(CONFIG_OF)
> > +
> > diff --git a/scripts/gdb/linux/proc.py b/scripts/gdb/linux/proc.py
> > index 38b1f09..f20fcfa 100644
> > --- a/scripts/gdb/linux/proc.py
> > +++ b/scripts/gdb/linux/proc.py
> > @@ -16,7 +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):
> >      """ Report the Linux Commandline used in the current kernel.
> > @@ -195,3 +195,71 @@ 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 a file
> > +       Equivalent to 'cat /proc/fdt > fdtdump.dtb' on a running target"""
> > +
> > +    def __init__(self):
> > +        super(LxFdtDump, self).__init__("lx-fdtdump", gdb.COMMAND_DATA)
> > +
> > +    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 constants.LX_CONFIG_OF:
> > +
> > +            filename = "fdtdump.dtb"
> 
> Why not specifying the file name as argument? Safer than silently
> overwriting potentially pre-existing files or failing without
> alternatives if the current directory is not writable.

Good idea, I will update to have the filename as the command argument in v2.

regards,

Peter

Re: [PATCH 1/2] scripts/gdb: add lx-fdtdump command

[Jan Kiszka]

On 2016-10-18 18:06, Peter Griffin wrote:
> Hi Jan,
> 
> On Tue, 18 Oct 2016, Jan Kiszka wrote:
> 
>> On 2016-10-18 17:07, Peter Griffin wrote:
>>> lx-fdtdump dumps the flatenned device tree passed to the kernel
>>> from the bootloader to a file called fdtdump.dtb to allow 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.
>>>
>>> Signed-off-by: Peter Griffin <peter.griffin-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
>>> ---
>>>  scripts/gdb/linux/constants.py.in |  8 +++++
>>>  scripts/gdb/linux/proc.py         | 70 ++++++++++++++++++++++++++++++++++++++-
>>>  2 files changed, 77 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/scripts/gdb/linux/constants.py.in b/scripts/gdb/linux/constants.py.in
>>> index 7986f4e..43c6241 100644
>>> --- a/scripts/gdb/linux/constants.py.in
>>> +++ b/scripts/gdb/linux/constants.py.in
>>> @@ -14,6 +14,7 @@
>>>  
>>>  #include <linux/fs.h>
>>>  #include <linux/mount.h>
>>> +#include <linux/of_fdt.h>
>>>  
>>>  /* We need to stringify expanded macros so that they can be parsed */
>>>  
>>> @@ -50,3 +51,10 @@ LX_VALUE(MNT_NOEXEC)
>>>  LX_VALUE(MNT_NOATIME)
>>>  LX_VALUE(MNT_NODIRATIME)
>>>  LX_VALUE(MNT_RELATIME)
>>> +
>>> +/* linux/of_fdt.h> */
>>> +LX_VALUE(OF_DT_HEADER)
>>> +
>>> +/* Kernel Configs */
>>> +LX_CONFIG(CONFIG_OF)
>>> +
>>> diff --git a/scripts/gdb/linux/proc.py b/scripts/gdb/linux/proc.py
>>> index 38b1f09..f20fcfa 100644
>>> --- a/scripts/gdb/linux/proc.py
>>> +++ b/scripts/gdb/linux/proc.py
>>> @@ -16,7 +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):
>>>      """ Report the Linux Commandline used in the current kernel.
>>> @@ -195,3 +195,71 @@ 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 a file
>>> +       Equivalent to 'cat /proc/fdt > fdtdump.dtb' on a running target"""
>>> +
>>> +    def __init__(self):
>>> +        super(LxFdtDump, self).__init__("lx-fdtdump", gdb.COMMAND_DATA)
>>> +
>>> +    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 constants.LX_CONFIG_OF:
>>> +
>>> +            filename = "fdtdump.dtb"
>>
>> Why not specifying the file name as argument? Safer than silently
>> overwriting potentially pre-existing files or failing without
>> alternatives if the current directory is not writable.
> 
> Good idea, I will update to have the filename as the command argument in v2.
> 

Also check gdb.COMPLETE_FILENAME [1] at that chance. :)

Jan

[1]
https://sourceware.org/gdb/onlinedocs/gdb/Commands-In-Python.html#Commands-In-Python

-- 
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Corporate Competence Center Embedded Linux
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Re: [PATCH 1/2] scripts/gdb: add lx-fdtdump command

[Peter Griffin]

Hi Jan,

On Tue, 18 Oct 2016, Jan Kiszka wrote:

> On 2016-10-18 18:06, Peter Griffin wrote:
> > Hi Jan,
> > 
> > On Tue, 18 Oct 2016, Jan Kiszka wrote:
> > 
> >> On 2016-10-18 17:07, Peter Griffin wrote:
> >>> lx-fdtdump dumps the flatenned device tree passed to the kernel
> >>> from the bootloader to a file called fdtdump.dtb to allow 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.
> >>>
> >>> Signed-off-by: Peter Griffin <peter.griffin-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> >>> ---
> >>>  scripts/gdb/linux/constants.py.in |  8 +++++
> >>>  scripts/gdb/linux/proc.py         | 70 ++++++++++++++++++++++++++++++++++++++-
> >>>  2 files changed, 77 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/scripts/gdb/linux/constants.py.in b/scripts/gdb/linux/constants.py.in
> >>> index 7986f4e..43c6241 100644
> >>> --- a/scripts/gdb/linux/constants.py.in
> >>> +++ b/scripts/gdb/linux/constants.py.in
> >>> @@ -14,6 +14,7 @@
> >>>  
> >>>  #include <linux/fs.h>
> >>>  #include <linux/mount.h>
> >>> +#include <linux/of_fdt.h>
> >>>  
> >>>  /* We need to stringify expanded macros so that they can be parsed */
> >>>  
> >>> @@ -50,3 +51,10 @@ LX_VALUE(MNT_NOEXEC)
> >>>  LX_VALUE(MNT_NOATIME)
> >>>  LX_VALUE(MNT_NODIRATIME)
> >>>  LX_VALUE(MNT_RELATIME)
> >>> +
> >>> +/* linux/of_fdt.h> */
> >>> +LX_VALUE(OF_DT_HEADER)
> >>> +
> >>> +/* Kernel Configs */
> >>> +LX_CONFIG(CONFIG_OF)
> >>> +
> >>> diff --git a/scripts/gdb/linux/proc.py b/scripts/gdb/linux/proc.py
> >>> index 38b1f09..f20fcfa 100644
> >>> --- a/scripts/gdb/linux/proc.py
> >>> +++ b/scripts/gdb/linux/proc.py
> >>> @@ -16,7 +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):
> >>>      """ Report the Linux Commandline used in the current kernel.
> >>> @@ -195,3 +195,71 @@ 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 a file
> >>> +       Equivalent to 'cat /proc/fdt > fdtdump.dtb' on a running target"""
> >>> +
> >>> +    def __init__(self):
> >>> +        super(LxFdtDump, self).__init__("lx-fdtdump", gdb.COMMAND_DATA)
> >>> +
> >>> +    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 constants.LX_CONFIG_OF:
> >>> +
> >>> +            filename = "fdtdump.dtb"
> >>
> >> Why not specifying the file name as argument? Safer than silently
> >> overwriting potentially pre-existing files or failing without
> >> alternatives if the current directory is not writable.
> > 
> > Good idea, I will update to have the filename as the command argument in v2.
> > 
> 
> Also check gdb.COMPLETE_FILENAME [1] at that chance. :)
> 
> Jan
> 
> [1]
> https://sourceware.org/gdb/onlinedocs/gdb/Commands-In-Python.html#Commands-In-Python
> 

Thanks for the tip, that is very cool!

Will add gdb.COMPLETE_FILENAME in V2.

regads,

Peter.
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