From: "Mingarelli, Thomas" <Thomas.Mingarelli@hp.com>
To: Wim Van Sebroeck <wim@iguana.be>,
Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maxim Uvarov <maxim.uvarov@oracle.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
dann frazier <dannf@hp.com>
Subject: RE: [PATCH] hpwdt: clean up set_memory_x call for 32 bit
Date: Tue, 24 Jan 2012 21:05:53 +0000 [thread overview]
Message-ID: <9774516974AF5F4C8A2C3C69CD3412332032E846@G9W0755.americas.hpqcorp.net> (raw)
In-Reply-To: <20120124203738.GA27296@infomag.iguana.be>
Yes I agree that Maxim's patch is correct. The original set_memory_x call for 64 bit was done correctly and the newer calls are wrong.
The 2 pages for the BIOS SD is a known value so it should be safe to use as is.
Tom
-----Original Message-----
From: Wim Van Sebroeck [mailto:wim@iguana.be]
Sent: Tuesday, January 24, 2012 2:38 PM
To: Linus Torvalds
Cc: Maxim Uvarov; linux-kernel@vger.kernel.org; akpm@linux-foundation.org; stable@vger.kernel.org; Mingarelli, Thomas; dann frazier
Subject: Re: [PATCH] hpwdt: clean up set_memory_x call for 32 bit
Hi Linus,
> So I don't know who is supposed to be handling this (Wim?), but the
> patch itself looks suspicious.
I asked Tom to look at Maxim's patch and see what it does. Tom was going to look at the patch and
I'm waiting on feedback from him first. (That's why I din't sent it upstream yet).
> On Sun, Jan 15, 2012 at 8:02 PM, Maxim Uvarov <maxim.uvarov@oracle.com> wrote:
> > - set_memory_x((unsigned long)bios32_entrypoint, (2 * PAGE_SIZE));
> > + set_memory_x((unsigned long)bios32_entrypoint & PAGE_MASK, 2);
>
> If it wasn't page-aligned to begin with, then maybe it needs three pages now?
>
> > - set_memory_x((unsigned long)cru_rom_addr, cru_length);
> > + set_memory_x((unsigned long)cru_rom_addr & PAGE_MASK, cru_length >> PAGE_SHIFT);
>
> Same here. If we align the start address down, we should fix up the
> length. And should we not align the number of pages up?
>
> In general, a "start/length" conversion to a "page/nr" model needs to be roughly
>
> len += start & ~PAGE_MASK;
> start &= PAGE_MASK;
> nr_pages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
>
> to do things right. But I don't know where those magic numbers come
> from. Maybe the "2" is already due to the code possibly traversing a
> page boundary, and has already been fixed up. Somebody who knows the
> driver and the requirements should take a look at this.
Valid comments indeed. Tom please take Linus comments with you when you look at the patch.
Dan: I put you in Cc: also so that you can have a look at it also.
Kind regards,
Wim.
next prev parent reply other threads:[~2012-01-24 21:06 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-16 4:02 hpwdt: clean up set_memory_x call for 32 bit Maxim Uvarov
2012-01-16 4:02 ` [PATCH] " Maxim Uvarov
2012-01-24 20:20 ` Linus Torvalds
2012-01-24 20:37 ` Wim Van Sebroeck
2012-01-24 21:05 ` Mingarelli, Thomas [this message]
2012-01-25 23:21 ` Maxim Uvarov
2012-01-26 0:01 ` Mingarelli, Thomas
2012-01-27 16:49 ` Wim Van Sebroeck
2012-01-27 16:55 ` Mingarelli, Thomas
2012-01-27 18:33 ` Maxim Uvarov
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