linux-kernel - Re: [PATCH 3/5] scripts/gdb: Add io resource readers

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Date:	Sun, 24 Jan 2016 00:17:06 +0000
From:	Kieran Bingham <kieran.bingham@...aro.org>
To:	Jan Kiszka <jan.kiszka@...mens.com>
Cc:	linux-kernel@...r.kernel.org, maxime.coquelin@...com,
	peter.griffin@...aro.org, lee.jones@...aro.org
Subject: Re: [PATCH 3/5] scripts/gdb: Add io resource readers



On 23/01/16 15:12, Jan Kiszka wrote:
> On 2016-01-20 12:15, Kieran Bingham wrote:
>> Provide iomem_resource and ioports_resource printers and command hooks
>>
>> Signed-off-by: Kieran Bingham <kieran.bingham@...aro.org>
>>
>> ---
>>
>> These two readers are a useful extract of kernel information.
>> This shows the power of having these commands in gdb/scripts as you can
>> halt a kernel as it's booting and read these as the structures grow.
>>
>> It should be useful in the event that a kernel is not booting, you
>> can identify what memory resources have been registered
>>
> 
> Ack. Maybe provide this reasoning in the commit log? I explains why we
> want this which is too often lacking in the persistent logs...
> 

Perfect,
I'll update the commit for v2.

--
Kieran


>>
>>
>>  scripts/gdb/linux/proc.py | 57 +++++++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 57 insertions(+)
>>
>> diff --git a/scripts/gdb/linux/proc.py b/scripts/gdb/linux/proc.py
>> index 6e6709c1830c..d855b2fd9a06 100644
>> --- a/scripts/gdb/linux/proc.py
>> +++ b/scripts/gdb/linux/proc.py
>> @@ -39,3 +39,60 @@ class LxVersion(gdb.Command):
>>          gdb.write(gdb.parse_and_eval("linux_banner").string())
>>  
>>  LxVersion()
>> +
>> +
>> +# Resource Structure Printers
>> +#  /proc/iomem
>> +#  /proc/ioports
>> +
>> +def get_resources(resource, depth):
>> +    while resource:
>> +        yield resource, depth
>> +
>> +        child = resource['child']
>> +        if child:
>> +            for res, deep in get_resources(child, depth + 1):
>> +                yield res, deep
>> +
>> +        resource = resource['sibling']
>> +
>> +
>> +def show_lx_resources(resource_str):
>> +        resource = gdb.parse_and_eval(resource_str)
>> +        width = 4 if resource['end'] < 0x10000 else 8
>> +        # Iterate straight to the first child
>> +        for res, depth in get_resources(resource['child'], 0):
>> +            start = int(res['start'])
>> +            end = int(res['end'])
>> +            gdb.write(" " * depth * 2 +
>> +                      "{0:0{1}x}-".format(start, width) +
>> +                      "{0:0{1}x} : ".format(end, width) +
>> +                      res['name'].string() + "\n")
>> +
>> +
>> +class LxIOMem(gdb.Command):
>> +    """Identify the IO memory resource locations defined by the kernel
>> +
>> +Equivalent to cat /proc/iomem on a running target"""
>> +
>> +    def __init__(self):
>> +        super(LxIOMem, self).__init__("lx-iomem", gdb.COMMAND_DATA)
>> +
>> +    def invoke(self, arg, from_tty):
>> +        return show_lx_resources("iomem_resource")
>> +
>> +LxIOMem()
>> +
>> +
>> +class LxIOPorts(gdb.Command):
>> +    """Identify the IO port resource locations defined by the kernel
>> +
>> +Equivalent to cat /proc/ioports on a running target"""
>> +
>> +    def __init__(self):
>> +        super(LxIOPorts, self).__init__("lx-ioports", gdb.COMMAND_DATA)
>> +
>> +    def invoke(self, arg, from_tty):
>> +        return show_lx_resources("ioport_resource")
>> +
>> +LxIOPorts()
>>
> 
> Looks good to me.
> 
> Jan
>