From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>, Yinghai Lu <yinghai.lu@sun.com>,
Yinghai Lu <yhlu.kernel@gmail.com>,
jbarnes@virtuousgeek.org
Subject: Re: [git pull] "big box" x86 changes, boot protocol
Date: Sat, 26 Apr 2008 16:37:43 -0700 [thread overview]
Message-ID: <4813BCC7.5040701@goop.org> (raw)
In-Reply-To: <20080426133928.a6f40caa.akpm@linux-foundation.org>
Andrew Morton wrote:
>> + memcpy(&early_res[i], &early_res[i + 1],
>> + (j - 1 - i) * sizeof(struct early_res));
>>
>
> nit: memcpy() shouldn't be used for overlapping copies. It happens to be
> OK (for dst<src) in the kernel implementations. We hope.
>
Definitely shouldn't be assumed. At one point in the distant past I had
a ppc memcpy which would clobber a destination cacheline before reading
the source, so source and dest within a cacheline's distance would be
trouble, regardless of the direction. Arch-specific code which knows
about the arch-specific details of memcpy might be safer, I guess, but
its still fairly brittle.
J
next prev parent reply other threads:[~2008-04-26 23:37 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-26 18:55 [RFC git pull] "big box" x86 changes Ingo Molnar
2008-04-26 19:05 ` Stefan Richter
2008-04-26 19:21 ` Ingo Molnar
2008-04-26 19:12 ` Linus Torvalds
2008-04-26 19:41 ` [git pull] "big box" x86 changes, bootmem/sparsemem Ingo Molnar
2008-04-26 19:52 ` Linus Torvalds
2008-04-26 20:07 ` Ingo Molnar
2008-04-26 20:08 ` [git pull] "big box" x86 changes, bootmem/sparsemem, #2 Ingo Molnar
2008-04-26 20:30 ` Linus Torvalds
2008-04-26 20:55 ` [git pull] "big box" x86 changes, bootmem/sparsemem, #3 Ingo Molnar
2008-04-27 22:48 ` [git pull] "big box" x86 changes, bootmem/sparsemem Johannes Weiner
2008-04-27 23:46 ` Ingo Molnar
2008-04-28 0:19 ` Johannes Weiner
2008-04-28 0:40 ` [patch] mm: node-setup agnostic free_bootmem() Ingo Molnar
2008-04-28 1:48 ` Yinghai Lu
2008-04-28 16:54 ` Johannes Weiner
2008-04-28 19:11 ` Yinghai Lu
2008-04-28 19:55 ` Yinghai Lu
2008-04-30 10:50 ` Johannes Weiner
2008-04-30 16:22 ` Yinghai Lu
2008-04-30 17:52 ` Johannes Weiner
2008-04-30 20:30 ` Yinghai Lu
2008-04-28 16:49 ` Johannes Weiner
2008-04-29 14:25 ` Ingo Molnar
2008-04-30 10:52 ` Johannes Weiner
2008-04-28 0:33 ` [git pull] "big box" x86 changes, bootmem/sparsemem Yinghai Lu
2008-04-28 16:58 ` Johannes Weiner
2008-04-26 19:54 ` [git pull] "big box" x86 changes, boot protocol Ingo Molnar
2008-04-26 20:39 ` Andrew Morton
2008-04-26 21:06 ` Adrian Bunk
2008-04-26 21:10 ` H. Peter Anvin
2008-04-26 21:11 ` Linus Torvalds
2008-04-26 21:17 ` Ingo Molnar
2008-04-26 23:37 ` Jeremy Fitzhardinge [this message]
2008-04-27 11:21 ` Ian Campbell
2008-04-27 19:29 ` H. Peter Anvin
2008-04-28 15:27 ` Ingo Molnar
2008-04-26 20:24 ` [RFC git pull] "big box" x86 changes, GART Ingo Molnar
2008-04-26 20:26 ` Ingo Molnar
2008-04-26 21:55 ` [git pull] "big box" x86 changes, PCI Ingo Molnar
2008-04-27 16:30 ` Jesse Barnes
2008-04-28 15:38 ` Ingo Molnar
2008-04-28 20:34 ` Jesse Barnes
2008-04-28 22:53 ` Yinghai Lu
2008-04-28 23:27 ` [PATCH] x86/pci: remove flag in pci_cfg_space_size_ext Yinghai Lu
2008-04-29 16:14 ` Jesse Barnes
2008-04-29 22:05 ` Ingo Molnar
2008-04-29 22:34 ` Jesse Barnes
2008-04-26 22:17 ` [RFC git pull] "big box" x86 changes Andi Kleen
2008-04-27 3:14 ` Yinghai Lu
2008-04-27 8:30 ` Andi Kleen
2008-04-27 8:32 ` [RFC git pull] "big box" x86 changes II Andi Kleen
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