From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Hugh Dickins <hughd@google.com>,
Dave Hansen <dave@linux.vnet.ibm.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Paul Mundt <lethal@linux-sh.org>
Subject: Re: mm: convert vma->vm_flags to 64bit
Date: Tue, 12 Apr 2011 21:30:58 +0100 [thread overview]
Message-ID: <20110412203058.GC7806@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20110411233358.dd400e59.akpm@linux-foundation.org>
On Mon, Apr 11, 2011 at 11:33:58PM -0700, Andrew Morton wrote:
> How the heck did we end up using 32 flags??
Good question.
> > @@ -217,7 +217,7 @@ vivt_flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned
> > {
> > if (cpumask_test_cpu(smp_processor_id(), mm_cpumask(vma->vm_mm)))
> > __cpuc_flush_user_range(start & PAGE_MASK, PAGE_ALIGN(end),
> > - vma->vm_flags);
> > + (unsigned long)vma->vm_flags);
> > }
>
> I'm surprised this change (and similar) are needed?
>
> Is it risky? What happens if we add yet another vm_flags bit and
> __cpuc_flush_user_range() wants to use it? I guess when that happens,
> __cpuc_flush_user_range() needs to be changed to take a ull.
The truncation is fine provided VM_EXEC is within the least significant
word. If it isn't, then we'll blow up when the cache handling assembly
gets parsed by the assembler as the VM_EXEC value will overflow.
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next prev parent reply other threads:[~2011-04-12 20:31 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-12 6:10 mm: convert vma->vm_flags to 64bit KOSAKI Motohiro
2011-04-12 6:33 ` Andrew Morton
2011-04-12 7:12 ` KOSAKI Motohiro
2011-04-12 11:06 ` Alexey Dobriyan
2011-04-12 11:11 ` Alexey Dobriyan
2011-04-12 22:07 ` Benjamin Herrenschmidt
2011-04-13 0:13 ` KOSAKI Motohiro
2011-04-13 6:44 ` Alexey Dobriyan
2011-04-13 7:00 ` Benjamin Herrenschmidt
2011-04-13 7:29 ` Russell King - ARM Linux
2011-04-13 8:56 ` Benjamin Herrenschmidt
2011-04-13 8:34 ` KOSAKI Motohiro
2011-04-13 7:04 ` KOSAKI Motohiro
2011-04-12 23:41 ` KOSAKI Motohiro
2011-04-13 2:19 ` [PATCH 1/3] mm: add __nocast attribute to vm_flags KOSAKI Motohiro
2011-04-13 2:20 ` [PATCH 2/3] fremap: convert vm_flags to unsigned long long KOSAKI Motohiro
2011-04-13 2:21 ` [PATCH 3/3] procfs: " KOSAKI Motohiro
2011-04-12 20:30 ` Russell King - ARM Linux [this message]
2011-04-18 0:26 ` mm: convert vma->vm_flags to 64bit Hugh Dickins
2011-04-18 1:21 ` KOSAKI Motohiro
2011-04-18 1:45 ` Benjamin Herrenschmidt
2011-04-18 3:34 ` KOSAKI Motohiro
2011-11-10 4:09 ` Nai Xia
2011-11-10 4:49 ` David Rientjes
2011-11-11 8:52 ` Russell King - ARM Linux
2011-11-10 17:22 ` KOSAKI Motohiro
2011-11-10 21:12 ` Benjamin Herrenschmidt
2011-11-10 21:49 ` KOSAKI Motohiro
2011-11-11 8:42 ` Russell King - ARM Linux
2011-11-11 2:09 ` Hugh Dickins
2011-11-11 4:31 ` Benjamin Herrenschmidt
2011-11-11 8:38 ` Nai Xia
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