[PATCH -sfr.git] MIPS: zboot: indent the nop instruction in delay slot

[PATCH -sfr.git] MIPS: zboot: indent the nop instruction in delay slot

[Wu Zhangjin]

This is for the commit c6adcc73663a71f2aa9e66796a9bd57fcb6a349a(MIPS:
add support for gzip/bzip2/lzma compressed kernel images)

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
---
 arch/mips/boot/compressed/head.S |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

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
 	END(start)
-- 
1.6.2.1

Re: [PATCH -sfr.git] MIPS: zboot: indent the nop instruction in delay slot

[Maciej W. Rozycki]

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
>  	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, but based on 
the manual delay slot scheduling this is built with .set noreorder in 
effect and as such the function lacks a delay slot fill for the trailing 
branch (which is also ill-formatted).

  Maciej

Re: [PATCH -sfr.git] MIPS: zboot: indent the nop instruction in delay slot

[Wu Zhangjin]

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