From: Arnd Bergmann <arnd@arndb.de>
To: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: vgoyal@redhat.com, ebiederm@xmission.com,
akpm@linux-foundation.org, cpw@sgi.com,
kumagai-atsushi@mxc.nes.nec.co.jp, lisa.mitchell@hp.com,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
zhangyanfei@cn.fujitsu.com, jingbai.ma@hp.com,
linux-mm@kvack.org, riel@redhat.com, walken@google.com,
hughd@google.com, kosaki.motohiro@jp.fujitsu.com
Subject: Re: [PATCH v8 9/9] vmcore: support mmap() on /proc/vmcore
Date: Thu, 06 Jun 2013 23:31:41 +0200 [thread overview]
Message-ID: <10307835.fkACLi6FUD@wuerfel> (raw)
In-Reply-To: <20130523052547.13864.83306.stgit@localhost6.localdomain6>
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
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next prev parent reply other threads:[~2013-06-06 21:31 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-23 5:24 [PATCH v8 0/9] kdump, " 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
2013-05-24 9:02 ` Maxim Uvarov
2013-05-27 1:49 ` HATAYAMA Daisuke
2013-05-30 9:14 ` Maxim Uvarov
2013-05-30 9:26 ` Zhang Yanfei
2013-05-30 10:30 ` Maxim Uvarov
2013-06-03 8:43 ` Atsushi Kumagai
2013-06-04 15:34 ` Maxim Uvarov
2013-06-07 1:11 ` Zhang Yanfei
2013-06-28 16:40 ` Maxim Uvarov
2013-06-30 23:53 ` HATAYAMA Daisuke
2013-07-01 14:34 ` Maxim Uvarov
2013-07-01 19:53 ` Andrew Morton
2013-07-02 7:00 ` Maxim Uvarov
2013-06-06 21:31 ` Arnd Bergmann [this message]
2013-06-07 1:01 ` HATAYAMA Daisuke
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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