Re: [PATCHv2 0/8] arm64: ftrace cleanup + FTRACE_WITH_REGS

[Amit Kachhap <Amit.Kachhap@arm.com>]

On 11/4/19 6:26 PM, Will Deacon wrote:
> On Sat, Nov 02, 2019 at 05:42:25PM +0530, Amit Daniel Kachhap wrote:
>> On 10/29/19 10:28 PM, Mark Rutland wrote:
>>> This series is a reworked version of Torsten's FTRACE_WITH_REGS series
>>> [1]. I've tried to rework the existing code in preparatory patches so
>>> that the patchable-function-entry bits slot in with fewer surprises.
>>> This version is based on v5.4-rc3, and can be found in my
>>> arm64/ftrace-with-regs branch [2].
>>>
>>> Patch 1 adds an (optional) ftrace_init_nop(), which the core code uses
>>> to initialize callsites. This allows us to avoid a synthetic MCOUNT_ADDR
>>> symbol, and more cleanly separates the one-time initialization of the
>>> callsite from dynamic NOP<->CALL modification. Architectures which don't
>>> implement this get the existing ftrace_make_nop() with MCOUNT_ADDR.
>>>
>>> Recently parisc gained ftrace support using patchable-function-entry.
>>> Patch 2 makes the handling of module callsite locations common in
>>> kernel/module.c with a new FTRACE_CALLSITE_SECTION definition, and
>>> removed the newly redundant bits from arch/parisc.
>>>
>>> Patches 3 and 4 move the module PLT initialization to module load time,
>>> which simplifies runtime callsite modification. This also means that we
>>> don't transitently mark the module text RW, and will allow for the
>>> removal of module_disable_ro().
>>>
>>> Patches 5 and 6 add some trivial infrastructure, with patch 7 finally
>>> adding FTRACE_WITH_REGS support. Additional work will be required for
>>> livepatching (e.g. implementing reliable stack trace), which is
>>> commented as part of patch 7.
>>>
>>> Patch 8 is a trivial cleanup atop of the rest of the series, making the
>>> code easier to read and less susceptible to config-specific breakage.
>> I tested the whole series with my latest in-kernel ptrauth patches [1]
>> and graph_tracer/function_graph_tracer works fine, So for the whole series,
>> Tested-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
>>
>> Also I gave few minor comments in the individual patches. With those
>> comments,
>> Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Oops sorry I meant,
Reviewed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
>
> I don't think this means what you think it means. Please read:
Thanks for pointing it.
>
> Documentation/process/submitting-patches.rst
>
> Will
>
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