From: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: riel@redhat.com, hughd@google.com, jingbai.ma@hp.com,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
lisa.mitchell@hp.com, linux-mm@kvack.org,
kumagai-atsushi@mxc.nes.nec.co.jp, ebiederm@xmission.com,
kosaki.motohiro@jp.fujitsu.com, zhangyanfei@cn.fujitsu.com,
akpm@linux-foundation.org, walken@google.com, cpw@sgi.com,
vgoyal@redhat.com
Subject: Re: [PATCH v8 9/9] vmcore: support mmap() on /proc/vmcore
Date: Fri, 07 Jun 2013 10:01:45 +0900 [thread overview]
Message-ID: <51B130F9.8070408@jp.fujitsu.com> (raw)
In-Reply-To: <10307835.fkACLi6FUD@wuerfel>
(2013/06/07 6:31), Arnd Bergmann wrote:
> On Thursday 23 May 2013 14:25:48 HATAYAMA Daisuke wrote:
>> This patch introduces mmap_vmcore().
>>
>> Don't permit writable nor executable mapping even with mprotect()
>> because this mmap() is aimed at reading crash dump memory.
>> Non-writable mapping is also requirement of remap_pfn_range() when
>> mapping linear pages on non-consecutive physical pages; see
>> is_cow_mapping().
>>
>> Set VM_MIXEDMAP flag to remap memory by remap_pfn_range and by
>> remap_vmalloc_range_pertial at the same time for a single
>> vma. do_munmap() can correctly clean partially remapped vma with two
>> functions in abnormal case. See zap_pte_range(), vm_normal_page() and
>> their comments for details.
>>
>> On x86-32 PAE kernels, mmap() supports at most 16TB memory only. This
>> limitation comes from the fact that the third argument of
>> remap_pfn_range(), pfn, is of 32-bit length on x86-32: unsigned long.
>>
>> Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
>> Acked-by: Vivek Goyal <vgoyal@redhat.com>
>
> I get build errors on 'make randconfig' from this, when building
> NOMMU kernels on ARM. I suppose the new feature should be hidden
> in #ifdef CONFIG_MMU.
>
> Arnd
>
Thanks for trying the build and your report!
OTOH, I don't have no-MMU architectures; x86 box only. I cannot reproduce this build error. Could you give me your build log? I want to use it to detect what part depends on CONFIG_MMU.
--
Thanks.
HATAYAMA, Daisuke
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next prev parent reply other threads:[~2013-06-07 1:02 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-23 5:24 [PATCH v8 0/9] kdump, vmcore: support mmap() on /proc/vmcore HATAYAMA Daisuke
2013-05-23 5:25 ` [PATCH v8 1/9] vmcore: clean up read_vmcore() HATAYAMA Daisuke
2013-05-23 5:25 ` [PATCH v8 2/9] vmcore: allocate buffer for ELF headers on page-size alignment HATAYAMA Daisuke
2013-05-23 14:22 ` Vivek Goyal
2013-05-23 21:46 ` Andrew Morton
2013-05-23 5:25 ` [PATCH v8 3/9] vmcore: treat memory chunks referenced by PT_LOAD program header entries in page-size boundary in vmcore_list HATAYAMA Daisuke
2013-05-23 21:49 ` Andrew Morton
2013-05-24 13:12 ` Vivek Goyal
2013-05-27 0:13 ` HATAYAMA Daisuke
2013-05-23 5:25 ` [PATCH v8 4/9] vmalloc: make find_vm_area check in range HATAYAMA Daisuke
2013-05-23 5:25 ` [PATCH v8 5/9] vmalloc: introduce remap_vmalloc_range_partial HATAYAMA Daisuke
2013-05-23 22:00 ` Andrew Morton
2013-05-23 5:25 ` [PATCH v8 6/9] vmcore: allocate ELF note segment in the 2nd kernel vmalloc memory HATAYAMA Daisuke
2013-05-23 14:28 ` Vivek Goyal
2013-05-23 22:17 ` Andrew Morton
2013-05-23 5:25 ` [PATCH v8 7/9] vmcore: Allow user process to remap ELF note segment buffer HATAYAMA Daisuke
2013-05-23 14:32 ` Vivek Goyal
2013-05-23 5:25 ` [PATCH v8 8/9] vmcore: calculate vmcore file size from buffer size and total size of vmcore objects HATAYAMA Daisuke
2013-05-23 14:34 ` Vivek Goyal
2013-05-23 5:25 ` [PATCH v8 9/9] vmcore: support mmap() on /proc/vmcore HATAYAMA Daisuke
2013-05-23 22:24 ` Andrew Morton
[not found] ` <CAJGZr0LwivLTH+E7WAR1B9_6B4e=jv04KgCUL_PdVpi9JjDpBw@mail.gmail.com>
2013-05-27 1:49 ` HATAYAMA Daisuke
[not found] ` <CAJGZr0LmsFXEgb3UXVb+rqo1aq5KJyNxyNAD+DG+3KnJm_ZncQ@mail.gmail.com>
2013-05-30 9:26 ` Zhang Yanfei
[not found] ` <CAJGZr0Ld6Q4a4f-VObAbvqCp=+fTFNEc6M-Fdnhh28GTcSm1=w@mail.gmail.com>
2013-06-03 8:43 ` Atsushi Kumagai
[not found] ` <CAJGZr0KV9hmdFWQE5Z9kOieHSPhGKLAhsw1Me2RE2ADsbU=b7w@mail.gmail.com>
2013-06-07 1:11 ` Zhang Yanfei
[not found] ` <CAJGZr0+9VUweN1Ssdq6P9Lug1GnTB3+RPv77JLRmnw=rpd9+Dw@mail.gmail.com>
2013-06-30 23:53 ` HATAYAMA Daisuke
[not found] ` <CAJGZr0Jwy6OLADBO9GExWVbwG_LMk41ZsSMZKvWmwcA9StVZQA@mail.gmail.com>
2013-07-01 19:53 ` Andrew Morton
2013-06-06 21:31 ` Arnd Bergmann
2013-06-07 1:01 ` HATAYAMA Daisuke [this message]
2013-06-07 18:34 ` Arnd Bergmann
2013-06-08 10:42 ` HATAYAMA Daisuke
2013-05-23 14:35 ` [PATCH v8 0/9] kdump, " Vivek Goyal
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