Re: [PATCH v8 01/16] scripts: link-vmlinux: Don't pass page offset to kallsyms if XIP Kernel

From: Andreas Färber
Date: Fri May 22 2015 - 16:21:08 EST


Am 21.05.2015 um 01:04 schrieb Andreas Färber:
> Hi,
>
> Am 18.05.2015 um 13:47 schrieb Maxime Coquelin:
>> 2015-05-09 9:53 GMT+02:00 Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx>:
>>> When Kernel is executed in place from ROM, the symbol addresses can be
>>> lower than the page offset.
>>>
>>> Tested-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
>>> Signed-off-by: Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx>
[...]
> Back then on STM32F4 I debugged that disabling KALLSYMS works around it.
>
> Now on a different XIP target I have confirmed this patch to help show a
> stacktrace (my clk driver was missing some CLK_DIVIDER_ALLOW_ZEROs) ...
> although my earlyprintk serial output still gets stuck further down the
> stacktrace - probably unrelated.

FTR confirming my suspicion: insufficient power supply. ;)

Andreas

> [ 0.000000] ------------[ cut here ]------------
> [ 0.000000] WARNING: CPU: 0 PID: 0 at drivers/clk/clk-divider.c:126
> divider_recalc_rate+0x2b/0x44()
> [ 0.000000] SYS: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set
> [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted
> 4.1.0-rc4-next-20150519+ #23
> [ 0.000000] Hardware name: XMC4000 (Device Tree Support)
> [ 0.000000] [<0800bd5d>] (unwind_backtrace) from [<0800b0cb>]
> (show_stack+0xb/0xc)
> [ 0.000000] [<0800b0cb>] (show_stack) from [<0800e0a5>]
> (warn_slowpath_common+0x55/0x78)
> [ 0.000000] [<0800e0a5>] (warn_slowpath_common) from [<0800e103>]
> (warn_slowpath_fmt+0x1b/0x24)
> [ 0.000000] [<0800e103>] (warn_slowpath_fmt) from [<080942e3>] (divide
>
> But this is definitely an improvement for ARMv7-M debugging,
>
> Tested-by: Andreas Färber <afaerber@xxxxxxx>

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