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

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Date:	Sat, 23 Jan 2016 16:12:01 +0100
From:	Jan Kiszka <jan.kiszka@...mens.com>
To:	Kieran Bingham <kieran.bingham@...aro.org>
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 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...

> 
> 
>  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

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