From: Thiago Jung Bauermann <bauerman@linux.ibm.com>
To: Hari Bathini <hbathini@linux.ibm.com>
Cc: Pingfan Liu <piliu@redhat.com>, Nayna Jain <nayna@linux.ibm.com>,
Kexec-ml <kexec@lists.infradead.org>,
Mahesh J Salgaonkar <mahesh@linux.ibm.com>,
Mimi Zohar <zohar@linux.ibm.com>,
lkml <linux-kernel@vger.kernel.org>,
linuxppc-dev <linuxppc-dev@ozlabs.org>,
Sourabh Jain <sourabhjain@linux.ibm.com>,
Petr Tesarik <ptesarik@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
Dave Young <dyoung@redhat.com>, Vivek Goyal <vgoyal@redhat.com>,
Eric Biederman <ebiederm@xmission.com>
Subject: Re: [PATCH v3 10/12] ppc64/kexec_file: prepare elfcore header for crashing kernel
Date: Thu, 16 Jul 2020 18:57:15 -0300 [thread overview]
Message-ID: <87a6zzcedg.fsf@morokweng.localdomain> (raw)
In-Reply-To: <929db6fe-b221-a514-8ea1-93227f8d47b0@linux.ibm.com>
Hari Bathini <hbathini@linux.ibm.com> writes:
> On 16/07/20 7:52 am, Thiago Jung Bauermann wrote:
>>
>> Hari Bathini <hbathini@linux.ibm.com> writes:
>>
>>> /**
>>> + * get_crash_memory_ranges - Get crash memory ranges. This list includes
>>> + * first/crashing kernel's memory regions that
>>> + * would be exported via an elfcore.
>>> + * @mem_ranges: Range list to add the memory ranges to.
>>> + *
>>> + * Returns 0 on success, negative errno on error.
>>> + */
>>> +static int get_crash_memory_ranges(struct crash_mem **mem_ranges)
>>> +{
>>> + struct memblock_region *reg;
>>> + struct crash_mem *tmem;
>>> + int ret;
>>> +
>>> + for_each_memblock(memory, reg) {
>>> + u64 base, size;
>>> +
>>> + base = (u64)reg->base;
>>> + size = (u64)reg->size;
>>> +
>>> + /* Skip backup memory region, which needs a separate entry */
>>> + if (base == BACKUP_SRC_START) {
>>> + if (size > BACKUP_SRC_SIZE) {
>>> + base = BACKUP_SRC_END + 1;
>>> + size -= BACKUP_SRC_SIZE;
>>> + } else
>>> + continue;
>>> + }
>>> +
>>> + ret = add_mem_range(mem_ranges, base, size);
>>> + if (ret)
>>> + goto out;
>>> +
>>> + /* Try merging adjacent ranges before reallocation attempt */
>>> + if ((*mem_ranges)->nr_ranges == (*mem_ranges)->max_nr_ranges)
>>> + sort_memory_ranges(*mem_ranges, true);
>>> + }
>>> +
>>> + /* Reallocate memory ranges if there is no space to split ranges */
>>> + tmem = *mem_ranges;
>>> + if (tmem && (tmem->nr_ranges == tmem->max_nr_ranges)) {
>>> + tmem = realloc_mem_ranges(mem_ranges);
>>> + if (!tmem)
>>> + goto out;
>>> + }
>>> +
>>> + /* Exclude crashkernel region */
>>> + ret = crash_exclude_mem_range(tmem, crashk_res.start, crashk_res.end);
>>> + if (ret)
>>> + goto out;
>>> +
>>> + ret = add_rtas_mem_range(mem_ranges);
>>> + if (ret)
>>> + goto out;
>>> +
>>> + ret = add_opal_mem_range(mem_ranges);
>>> + if (ret)
>>> + goto out;
>>
>> Maybe I'm confused, but don't you add the RTAS and OPAL regions as
>> usable memory for the crashkernel? In that case they shouldn't show up
>> in the core file.
>
> kexec-tools does the same thing. I am not endorsing it but I was trying to stay
> in parity to avoid breaking any userspace tools/commands. But as you rightly
> pointed, this is NOT right. The right thing to do, to get the rtas/opal data at
> the time of crash, is to have a backup region for them just like we have for
> the first 64K memory. I was hoping to do that later.
>
> Will check how userspace tools respond to dropping these regions. If that makes
> the tools unhappy, will retain the regions with a FIXME. Sorry about the confusion.
No problem, thanks for the clarification.
--
Thiago Jung Bauermann
IBM Linux Technology Center
next prev parent reply other threads:[~2020-07-16 21:57 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-13 17:20 [PATCH v3 00/12] ppc64: enable kdump support for kexec_file_load syscall Hari Bathini
2020-07-13 17:20 ` [PATCH v3 01/12] kexec_file: allow archs to handle special regions while locating memory hole Hari Bathini
2020-07-14 21:00 ` Thiago Jung Bauermann
2020-07-13 17:21 ` [PATCH v3 02/12] powerpc/kexec_file: mark PPC64 specific code Hari Bathini
2020-07-16 1:49 ` Thiago Jung Bauermann
2020-07-17 4:46 ` Hari Bathini
2020-07-17 18:34 ` Thiago Jung Bauermann
2020-07-13 17:21 ` [PATCH v3 03/12] powerpc/kexec_file: add helper functions for getting memory ranges Hari Bathini
2020-07-14 23:49 ` Thiago Jung Bauermann
2020-07-16 21:08 ` Hari Bathini
2020-07-17 4:32 ` Hari Bathini
2020-07-17 20:00 ` Hari Bathini
2020-07-13 17:21 ` [PATCH v3 04/12] ppc64/kexec_file: avoid stomping memory used by special regions Hari Bathini
2020-07-15 2:39 ` Thiago Jung Bauermann
2020-07-16 5:58 ` Thiago Jung Bauermann
2020-07-16 21:09 ` Hari Bathini
2020-07-16 21:59 ` Thiago Jung Bauermann
2020-07-13 17:21 ` [PATCH v3 05/12] powerpc/drmem: make lmb walk a bit more flexible Hari Bathini
2020-07-15 3:50 ` Thiago Jung Bauermann
2020-07-16 21:09 ` Hari Bathini
2020-07-16 22:01 ` Thiago Jung Bauermann
2020-07-13 17:22 ` [PATCH v3 06/12] ppc64/kexec_file: restrict memory usage of kdump kernel Hari Bathini
2020-07-15 22:52 ` Thiago Jung Bauermann
2020-07-16 21:10 ` Hari Bathini
2020-07-16 22:03 ` Thiago Jung Bauermann
2020-07-17 4:17 ` Hari Bathini
2020-07-13 17:22 ` [PATCH v3 07/12] ppc64/kexec_file: add support to relocate purgatory Hari Bathini
2020-07-16 0:20 ` Thiago Jung Bauermann
2020-07-16 21:11 ` Hari Bathini
2020-07-16 22:12 ` Thiago Jung Bauermann
2020-07-13 17:22 ` [PATCH v3 08/12] ppc64/kexec_file: setup the stack for purgatory Hari Bathini
2020-07-16 0:35 ` Thiago Jung Bauermann
2020-07-16 1:40 ` Thiago Jung Bauermann
2020-07-13 17:22 ` [PATCH v3 09/12] ppc64/kexec_file: setup backup region for kdump kernel Hari Bathini
2020-07-16 1:38 ` Thiago Jung Bauermann
2020-07-16 21:10 ` Hari Bathini
2020-07-16 22:06 ` Thiago Jung Bauermann
2020-07-13 17:23 ` [PATCH v3 10/12] ppc64/kexec_file: prepare elfcore header for crashing kernel Hari Bathini
2020-07-16 2:22 ` Thiago Jung Bauermann
2020-07-16 21:07 ` Hari Bathini
2020-07-16 21:57 ` Thiago Jung Bauermann [this message]
2020-07-13 17:23 ` [PATCH v3 11/12] ppc64/kexec_file: add appropriate regions for memory reserve map Hari Bathini
2020-07-16 2:27 ` Thiago Jung Bauermann
2020-07-13 17:23 ` [PATCH v3 12/12] ppc64/kexec_file: fix kexec load failure with lack of memory hole Hari Bathini
2020-07-16 5:43 ` Thiago Jung Bauermann
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