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From: Wu Fengguang <fengguang.wu@intel.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>, Tejun Heo <tj@kernel.org>,
	Ingo Molnar <mingo@elte.hu>, Andi Kleen <andi@firstfloor.org>,
	Hugh Dickins <hugh.dickins@tiscali.co.uk>,
	Christoph Lameter <cl@linux-foundation.org>,
	Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: [PATCH 5/8] vmalloc: simplify vread()/vwrite()
Date: Thu, 21 Jan 2010 13:49:32 +0800	[thread overview]
Message-ID: <20100121054932.GD24236@localhost> (raw)
In-Reply-To: <20100121142106.c13c2bbf.kamezawa.hiroyu@jp.fujitsu.com>

On Wed, Jan 20, 2010 at 10:21:06PM -0700, KAMEZAWA Hiroyuki wrote:
> On Thu, 21 Jan 2010 13:05:21 +0800
> Wu Fengguang <fengguang.wu@intel.com> wrote:
> 
> > On Mon, Jan 18, 2010 at 07:23:43PM -0700, KAMEZAWA Hiroyuki wrote:

> > I did some audit and find that
> > 
> > - set_memory_uc(), set_memory_array_uc(), set_pages_uc(),
> >   set_pages_array_uc() are called EFI code and various video drivers,
> >   all of them don't touch HIGHMEM RAM
> > 
> > - Kame: ioremap() won't allow remap of physical RAM
> > 
> > So kmap_atomic() is safe.  Let's just settle on this patch?
> > 
> I recommend you to keep check on VM_IOREMAP. That was checked far before
> I started to see Linux. Some _unknown_ driver can call get_vm_area() and
> map arbitrary pages there.

OK, I'll turn this patch into a less radical one.

Thanks,
Fengguang

WARNING: multiple messages have this Message-ID (diff)
From: Wu Fengguang <fengguang.wu@intel.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>, Tejun Heo <tj@kernel.org>,
	Ingo Molnar <mingo@elte.hu>, Andi Kleen <andi@firstfloor.org>,
	Hugh Dickins <hugh.dickins@tiscali.co.uk>,
	Christoph Lameter <cl@linux-foundation.org>,
	Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: [PATCH 5/8] vmalloc: simplify vread()/vwrite()
Date: Thu, 21 Jan 2010 13:49:32 +0800	[thread overview]
Message-ID: <20100121054932.GD24236@localhost> (raw)
In-Reply-To: <20100121142106.c13c2bbf.kamezawa.hiroyu@jp.fujitsu.com>

On Wed, Jan 20, 2010 at 10:21:06PM -0700, KAMEZAWA Hiroyuki wrote:
> On Thu, 21 Jan 2010 13:05:21 +0800
> Wu Fengguang <fengguang.wu@intel.com> wrote:
> 
> > On Mon, Jan 18, 2010 at 07:23:43PM -0700, KAMEZAWA Hiroyuki wrote:

> > I did some audit and find that
> > 
> > - set_memory_uc(), set_memory_array_uc(), set_pages_uc(),
> >   set_pages_array_uc() are called EFI code and various video drivers,
> >   all of them don't touch HIGHMEM RAM
> > 
> > - Kame: ioremap() won't allow remap of physical RAM
> > 
> > So kmap_atomic() is safe.  Let's just settle on this patch?
> > 
> I recommend you to keep check on VM_IOREMAP. That was checked far before
> I started to see Linux. Some _unknown_ driver can call get_vm_area() and
> map arbitrary pages there.

OK, I'll turn this patch into a less radical one.

Thanks,
Fengguang

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  reply	other threads:[~2010-01-21  5:49 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-13 13:53 [PATCH 0/8] devmem/kmem/kcore fixes, cleanups and hwpoison checks Wu Fengguang
2010-01-13 13:53 ` Wu Fengguang
2010-01-13 13:53 ` [PATCH 1/8] vfs: fix too big f_pos handling Wu Fengguang
2010-01-13 13:53   ` Wu Fengguang
2010-01-13 13:53 ` [PATCH 2/8] devmem: check vmalloc address on kmem read/write Wu Fengguang
2010-01-13 13:53   ` Wu Fengguang
2010-01-13 13:53 ` [PATCH 3/8] devmem: fix kmem write bug on memory holes Wu Fengguang
2010-01-13 13:53   ` Wu Fengguang
2010-01-13 13:53 ` [PATCH 4/8] resources: introduce generic page_is_ram() Wu Fengguang
2010-01-13 13:53   ` Wu Fengguang
2010-01-13 13:53   ` Wu Fengguang
2010-01-13 14:29   ` Américo Wang
2010-01-13 14:29     ` Américo Wang
2010-01-14  3:29     ` Wu Fengguang
2010-01-14  3:29       ` Wu Fengguang
2010-01-13 13:53 ` [PATCH 5/8] vmalloc: simplify vread()/vwrite() Wu Fengguang
2010-01-13 13:53   ` Wu Fengguang
2010-01-14 12:45   ` Nick Piggin
2010-01-14 12:45     ` Nick Piggin
2010-01-18 13:35     ` Wu Fengguang
2010-01-18 13:35       ` Wu Fengguang
2010-01-18 14:23       ` Nick Piggin
2010-01-18 14:23         ` Nick Piggin
2010-01-19  1:33         ` Wu Fengguang
2010-01-19  1:33           ` Wu Fengguang
2010-01-19  2:23           ` KAMEZAWA Hiroyuki
2010-01-19  2:23             ` KAMEZAWA Hiroyuki
2010-01-21  5:05             ` Wu Fengguang
2010-01-21  5:05               ` Wu Fengguang
2010-01-21  5:21               ` KAMEZAWA Hiroyuki
2010-01-21  5:21                 ` KAMEZAWA Hiroyuki
2010-01-21  5:49                 ` Wu Fengguang [this message]
2010-01-21  5:49                   ` Wu Fengguang
2010-01-13 13:53 ` [PATCH 6/8] hwpoison: prevent /dev/kmem from accessing hwpoison pages Wu Fengguang
2010-01-13 13:53   ` Wu Fengguang
2010-01-13 13:53 ` [PATCH 7/8] hwpoison: prevent /dev/mem " Wu Fengguang
2010-01-13 13:53   ` Wu Fengguang
2010-01-13 13:53 ` [PATCH 8/8] hwpoison: prevent /dev/kcore " Wu Fengguang
2010-01-13 13:53   ` Wu Fengguang
2010-01-13 14:23   ` Américo Wang
2010-01-13 14:23     ` Américo Wang

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