From: Wu Zhangjin <wuzhangjin@gmail.com>
To: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: Ralf Baechle <ralf@linux-mips.org>,
Linux-MIPS <linux-mips@linux-mips.org>,
Robert Richter <robert.richter@amd.com>,
chenj@lemote.com
Subject: Re: [PATCH -sfr.git] MIPS: zboot: indent the nop instruction in delay slot
Date: Thu, 29 Oct 2009 13:26:57 +0800 [thread overview]
Message-ID: <1256794017.6448.22.camel@falcon> (raw)
In-Reply-To: <alpine.LFD.2.00.0910290306490.9323@eddie.linux-mips.org>
Hi,
On Thu, 2009-10-29 at 03:12 +0000, Maciej W. Rozycki wrote:
> On Thu, 29 Oct 2009, Wu Zhangjin wrote:
>
> > diff --git a/arch/mips/boot/compressed/head.S b/arch/mips/boot/compressed/head.S
> > index e23f25e..29080f4 100644
> > --- a/arch/mips/boot/compressed/head.S
> > +++ b/arch/mips/boot/compressed/head.S
> > @@ -38,7 +38,7 @@ start:
> > PTR_LA ra, 2f
> > PTR_LA k0, decompress_kernel
> > jr k0
> > - nop
> > + nop
> > 2:
> > move a0, s0
> > move a1, s1
> > @@ -46,7 +46,7 @@ start:
> > move a3, s3
> > PTR_LI k0, KERNEL_ENTRY
> > jr k0
> > - nop
> > + nop
> > 3:
> > b 3b
need to add one nop here.
> > END(start)
>
> This piece of code looks unsafe to me. I'm not sure which tree this is
> against and certainly I don't have a local copy of the file,
This is against the of mips-for-linux-next branh of Ralf's
http://www.linux-mips.org/git?p=upstream-sfr.git;a=summary
> but based on
> the manual delay slot scheduling this is built with .set noreorder in
> effect
Yes, there is exactly a ".set noreorder" there:
arch/mips/boot/compressed/head.S:
[...]
17
18 .set noreorder
19 .cprestore
20 LEAF(start)
21 start:
22 /* Save boot rom start args */
23 move s0, a0
24 move s1, a1
25 move s2, a2
26 move s3, a3
27
28 /* Clear BSS */
[...]
> and as such the function lacks a delay slot fill for the trailing
> branch (which is also ill-formatted).
A new version will be sent out, thanks!
Regards,
Wu Zhangjin
prev parent reply other threads:[~2009-10-29 5:27 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-29 2:10 [PATCH -sfr.git] MIPS: zboot: indent the nop instruction in delay slot Wu Zhangjin
2009-10-29 3:12 ` Maciej W. Rozycki
2009-10-29 5:26 ` Wu Zhangjin [this message]
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