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From: Hari Bathini <hbathini@linux.ibm.com>
To: Mahesh Jagannath Salgaonkar <mahesh@linux.vnet.ibm.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	linuxppc-dev <linuxppc-dev@ozlabs.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.ibm.com>,
	Mahesh J Salgaonkar <mahesh@linux.ibm.com>,
	Nicholas Piggin <npiggin@gmail.com>, Oliver <oohall@gmail.com>,
	Vasant Hegde <hegdevasant@linux.ibm.com>,
	Daniel Axtens <dja@axtens.net>
Subject: Re: [PATCH v5 02/31] powerpc/fadump: move internal code to a new file
Date: Wed, 4 Sep 2019 23:56:44 +0530
Message-ID: <012215ea-99ab-1993-4eb2-0d3fc248a1ea@linux.ibm.com> (raw)
In-Reply-To: <3c6bacc2-777d-a66c-0c43-79b9fbe76c15@linux.vnet.ibm.com>



On 04/09/19 2:32 PM, Mahesh Jagannath Salgaonkar wrote:
> On 9/3/19 9:35 PM, Hari Bathini wrote:
>>
>>
>> On 03/09/19 4:39 PM, Michael Ellerman wrote:
>>> Hari Bathini <hbathini@linux.ibm.com> writes:
>>>> Make way for refactoring platform specific FADump code by moving code
>>>> that could be referenced from multiple places to fadump-common.c file.
>>>>
>>>> Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
>>>> ---
>>>>  arch/powerpc/kernel/Makefile        |    2 
>>>>  arch/powerpc/kernel/fadump-common.c |  140 ++++++++++++++++++++++++++++++++++
>>>>  arch/powerpc/kernel/fadump-common.h |    8 ++
>>>>  arch/powerpc/kernel/fadump.c        |  146 ++---------------------------------
>>>>  4 files changed, 158 insertions(+), 138 deletions(-)
>>>>  create mode 100644 arch/powerpc/kernel/fadump-common.c
>>>
>>> I don't understand why we need fadump.c and fadump-common.c? They're
>>> both common/shared across pseries & powernv aren't they?
>>
>> The convention I tried to follow to have fadump-common.c shared between fadump.c,
>> pseries & powernv code while pseries & powernv code take callback requests from
>> fadump.c and use fadump-common.c (shared by both platforms), if necessary to fullfil
>> those requests...
>>
>>> By the end of the series we end up with 149 lines in fadump-common.c
>>> which seems like a waste of time. Just put it all in fadump.c.
>>
>> Yeah. Probably not worth a new C file. Will just have two separate headers. One for
>> internal code and one for interfacing with other modules...
>>
>> [...]
>>
>>>> + * Copyright 2019, IBM Corp.
>>>> + * Author: Hari Bathini <hbathini@linux.ibm.com>
>>>
>>> These can just be:
>>>
>>>  * Copyright 2011, Mahesh Salgaonkar, IBM Corporation.
>>>  * Copyright 2019, Hari Bathini, IBM Corporation.
>>>
>>
>> Sure.
>>
>>>> + */
>>>> +
>>>> +#undef DEBUG
>>>
>>> Don't undef DEBUG please.
>>>
>>
>> Sorry! Seeing such thing in most files, I thought this was the convention. Will drop
>> this change in all the new files I added.
>>
>>>> +#define pr_fmt(fmt) "fadump: " fmt
>>>> +
>>>> +#include <linux/memblock.h>
>>>> +#include <linux/elf.h>
>>>> +#include <linux/mm.h>
>>>> +#include <linux/crash_core.h>
>>>> +
>>>> +#include "fadump-common.h"
>>>> +
>>>> +void *fadump_cpu_notes_buf_alloc(unsigned long size)
>>>> +{
>>>> +	void *vaddr;
>>>> +	struct page *page;
>>>> +	unsigned long order, count, i;
>>>> +
>>>> +	order = get_order(size);
>>>> +	vaddr = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, order);
>>>> +	if (!vaddr)
>>>> +		return NULL;
>>>> +
>>>> +	count = 1 << order;
>>>> +	page = virt_to_page(vaddr);
>>>> +	for (i = 0; i < count; i++)
>>>> +		SetPageReserved(page + i);
>>>> +	return vaddr;
>>>> +}
>>>
>>> I realise you're just moving this code, but why do we need all this hand
>>> rolled allocation stuff?
>>
>> Yeah, I think alloc_pages_exact() may be better here. Mahesh, am I missing something?
> 
> We hook up the physical address of this buffer to ELF core header as
> PT_NOTE section. Hence we don't want these pages to be moved around or
> reclaimed.

alloc_pages_exact() + mark_page_reserved() should take care of that, I guess..

- Hari


  reply index

Thread overview: 74+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-20 12:04 [PATCH v5 00/31] Add FADump support on PowerNV platform Hari Bathini
2019-08-20 12:04 ` [PATCH v5 01/31] powerpc/fadump: move internal macros/definitions to a new header Hari Bathini
2019-09-03 11:09   ` Michael Ellerman
2019-09-03 16:05     ` Hari Bathini
2019-08-20 12:04 ` [PATCH v5 02/31] powerpc/fadump: move internal code to a new file Hari Bathini
2019-09-03 11:09   ` Michael Ellerman
2019-09-03 16:05     ` Hari Bathini
2019-09-04  9:02       ` Mahesh Jagannath Salgaonkar
2019-09-04 18:26         ` Hari Bathini [this message]
2019-08-20 12:04 ` [PATCH v5 03/31] powerpc/fadump: Improve fadump documentation Hari Bathini
2019-08-20 12:04 ` [PATCH v5 04/31] pseries/fadump: move rtas specific definitions to platform code Hari Bathini
2019-08-20 12:04 ` [PATCH v5 05/31] pseries/fadump: introduce callbacks for platform specific operations Hari Bathini
2019-09-03 11:10   ` Michael Ellerman
2019-09-03 16:06     ` Hari Bathini
2019-09-06  6:39       ` Hari Bathini
2019-08-20 12:04 ` [PATCH v5 06/31] pseries/fadump: define register/un-register callback functions Hari Bathini
2019-09-03 11:10   ` Michael Ellerman
2019-09-03 17:15     ` Hari Bathini
2019-08-20 12:04 ` [PATCH v5 07/31] powerpc/fadump: release all the memory above boot memory size Hari Bathini
2019-09-03 11:10   ` Michael Ellerman
2019-09-03 16:27     ` Hari Bathini
2019-08-20 12:05 ` [PATCH v5 08/31] pseries/fadump: move out platform specific support from generic code Hari Bathini
2019-08-20 12:05 ` [PATCH v5 09/31] powerpc/fadump: use FADump instead of fadump for how it is pronounced Hari Bathini
2019-08-20 12:05 ` [PATCH v5 10/31] opal: add MPIPL interface definitions Hari Bathini
2019-09-03 11:10   ` Michael Ellerman
2019-09-03 16:28     ` Hari Bathini
2019-09-04 11:03       ` Michael Ellerman
2019-09-04 11:05   ` Michael Ellerman
2019-08-20 12:05 ` [PATCH v5 11/31] powernv/fadump: add fadump support on powernv Hari Bathini
2019-09-03 11:10   ` Michael Ellerman
2019-09-03 16:31     ` Hari Bathini
2019-09-04 14:33       ` Hari Bathini
2019-09-05  3:11         ` Michael Ellerman
2019-08-20 12:05 ` [PATCH v5 12/31] powernv/fadump: register kernel metadata address with opal Hari Bathini
2019-09-04 11:25   ` Michael Ellerman
2019-08-20 12:05 ` [PATCH v5 13/31] powernv/fadump: reset metadata address during clean up Hari Bathini
2019-08-27 12:00   ` Hari Bathini
2019-08-20 12:05 ` [PATCH v5 14/31] powernv/fadump: define register/un-register callback functions Hari Bathini
2019-09-05  4:15   ` Michael Ellerman
2019-09-05  7:23   ` Michael Ellerman
2019-09-05  9:54     ` Hari Bathini
2019-08-20 12:05 ` [PATCH v5 15/31] powernv/fadump: support copying multiple kernel boot memory regions Hari Bathini
2019-09-04 11:30   ` Michael Ellerman
2019-09-04 20:20     ` Hari Bathini
2019-09-05  3:13       ` Michael Ellerman
2019-08-20 12:06 ` [PATCH v5 16/31] powernv/fadump: process the crashdump by exporting it as /proc/vmcore Hari Bathini
2019-09-04 11:42   ` Michael Ellerman
2019-09-04 21:01     ` Hari Bathini
2019-08-20 12:06 ` [PATCH v5 17/31] powernv/fadump: Warn before processing partial crashdump Hari Bathini
2019-09-04 11:48   ` Michael Ellerman
2019-08-20 12:06 ` [PATCH v5 18/31] powernv/fadump: handle invalidation of crashdump and re-registraion Hari Bathini
2019-08-20 12:06 ` [PATCH v5 19/31] powerpc/fadump: Update documentation about OPAL platform support Hari Bathini
2019-09-04 11:51   ` Michael Ellerman
2019-09-04 12:08     ` Oliver O'Halloran
2019-09-05  3:15       ` Michael Ellerman
2019-08-20 12:06 ` [PATCH v5 20/31] powerpc/fadump: use smaller offset while finding memory for reservation Hari Bathini
2019-09-04 11:54   ` Michael Ellerman
2019-08-20 12:06 ` [PATCH v5 21/31] powernv/fadump: process architected register state data provided by firmware Hari Bathini
2019-09-04 12:20   ` Michael Ellerman
2019-09-09 13:23     ` Hari Bathini
2019-09-09 15:33       ` Oliver O'Halloran
2019-09-10  8:48         ` Hari Bathini
2019-09-10 14:05           ` Michael Ellerman
2019-09-10 16:10             ` Hari Bathini
2019-08-20 12:06 ` [PATCH v5 22/31] powerpc/fadump: make crash memory ranges array allocation generic Hari Bathini
2019-08-20 12:06 ` [PATCH v5 23/31] powerpc/fadump: consider reserved ranges while releasing memory Hari Bathini
2019-08-20 12:07 ` [PATCH v5 24/31] powerpc/fadump: improve how crashed kernel's memory is reserved Hari Bathini
2019-08-20 12:07 ` [PATCH v5 25/31] powernv/fadump: add support to preserve crash data on FADUMP disabled kernel Hari Bathini
2019-08-20 12:07 ` [PATCH v5 26/31] powerpc/fadump: update documentation about CONFIG_PRESERVE_FA_DUMP Hari Bathini
2019-08-20 12:07 ` [PATCH v5 27/31] powernv/opalcore: export /sys/firmware/opal/core for analysing opal crashes Hari Bathini
2019-08-20 12:07 ` [PATCH v5 28/31] powernv/opalcore: provide an option to invalidate /sys/firmware/opal/core file Hari Bathini
2019-08-20 12:07 ` [PATCH v5 29/31] powerpc/fadump: consider f/w load area Hari Bathini
2019-08-20 12:07 ` [PATCH v5 30/31] powernv/fadump: update documentation about option to release opalcore Hari Bathini
2019-08-20 12:07 ` [PATCH v5 31/31] powernv/fadump: support holes in kernel boot memory area Hari Bathini

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