2020-02-05 23:09:54

by Stefan Agner

[permalink] [raw]
Subject: [PATCH] ARM: kexec: drop invalid assembly argument

The tst menomic has only a single #<const> argument in Thumb mode. There
is an ARM variant which allows to write #<const> as #<byte>, #<rot>
which probably is where the current syntax comes from.

It seems that binutils does not care about the additional parameter.
Clang however complains in Thumb2 mode:
arch/arm/kernel/relocate_kernel.S:28:12: error: too many operands for
instruction
tst r3,#1,0
^

Drop the unnecessary parameter. This fixes building this file in Thumb2
mode with the Clang integrated assembler.

Link: https://github.com/ClangBuiltLinux/linux/issues/770
Signed-off-by: Stefan Agner <[email protected]>
---
arch/arm/kernel/relocate_kernel.S | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arm/kernel/relocate_kernel.S b/arch/arm/kernel/relocate_kernel.S
index 7eaa2ae7aff5..72a08786e16e 100644
--- a/arch/arm/kernel/relocate_kernel.S
+++ b/arch/arm/kernel/relocate_kernel.S
@@ -25,26 +25,26 @@ ENTRY(relocate_new_kernel)
ldr r3, [r0],#4

/* Is it a destination page. Put destination address to r4 */
- tst r3,#1,0
+ tst r3,#1
beq 1f
bic r4,r3,#1
b 0b
1:
/* Is it an indirection page */
- tst r3,#2,0
+ tst r3,#2
beq 1f
bic r0,r3,#2
b 0b
1:

/* are we done ? */
- tst r3,#4,0
+ tst r3,#4
beq 1f
b 2f

1:
/* is it source ? */
- tst r3,#8,0
+ tst r3,#8
beq 0b
bic r3,r3,#8
mov r6,#1024
--
2.25.0


2020-02-05 23:57:18

by Russell King (Oracle)

[permalink] [raw]
Subject: Re: [PATCH] ARM: kexec: drop invalid assembly argument

On Wed, Feb 05, 2020 at 11:59:26PM +0100, Stefan Agner wrote:
> The tst menomic has only a single #<const> argument in Thumb mode. There
> is an ARM variant which allows to write #<const> as #<byte>, #<rot>
> which probably is where the current syntax comes from.
>
> It seems that binutils does not care about the additional parameter.
> Clang however complains in Thumb2 mode:
> arch/arm/kernel/relocate_kernel.S:28:12: error: too many operands for
> instruction
> tst r3,#1,0
> ^
>
> Drop the unnecessary parameter. This fixes building this file in Thumb2
> mode with the Clang integrated assembler.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/770
> Signed-off-by: Stefan Agner <[email protected]>

Please drop it in the patch system, thanks.

> ---
> arch/arm/kernel/relocate_kernel.S | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/kernel/relocate_kernel.S b/arch/arm/kernel/relocate_kernel.S
> index 7eaa2ae7aff5..72a08786e16e 100644
> --- a/arch/arm/kernel/relocate_kernel.S
> +++ b/arch/arm/kernel/relocate_kernel.S
> @@ -25,26 +25,26 @@ ENTRY(relocate_new_kernel)
> ldr r3, [r0],#4
>
> /* Is it a destination page. Put destination address to r4 */
> - tst r3,#1,0
> + tst r3,#1
> beq 1f
> bic r4,r3,#1
> b 0b
> 1:
> /* Is it an indirection page */
> - tst r3,#2,0
> + tst r3,#2
> beq 1f
> bic r0,r3,#2
> b 0b
> 1:
>
> /* are we done ? */
> - tst r3,#4,0
> + tst r3,#4
> beq 1f
> b 2f
>
> 1:
> /* is it source ? */
> - tst r3,#8,0
> + tst r3,#8
> beq 0b
> bic r3,r3,#8
> mov r6,#1024
> --
> 2.25.0
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> [email protected]
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>

--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to speedtest.net: 11.9Mbps down 500kbps up

2020-02-21 21:10:17

by Nick Desaulniers

[permalink] [raw]
Subject: Re: [PATCH] ARM: kexec: drop invalid assembly argument

On Wed, Feb 5, 2020 at 3:54 PM Russell King - ARM Linux admin
<[email protected]> wrote:
>
> On Wed, Feb 05, 2020 at 11:59:26PM +0100, Stefan Agner wrote:
> > The tst menomic has only a single #<const> argument in Thumb mode. There
> > is an ARM variant which allows to write #<const> as #<byte>, #<rot>
> > which probably is where the current syntax comes from.
> >
> > It seems that binutils does not care about the additional parameter.
> > Clang however complains in Thumb2 mode:
> > arch/arm/kernel/relocate_kernel.S:28:12: error: too many operands for
> > instruction
> > tst r3,#1,0
> > ^
> >
> > Drop the unnecessary parameter. This fixes building this file in Thumb2
> > mode with the Clang integrated assembler.
> >
> > Link: https://github.com/ClangBuiltLinux/linux/issues/770
> > Signed-off-by: Stefan Agner <[email protected]>
>
> Please drop it in the patch system, thanks.

Hi Stefan, did you add this to the patch tracking system? Looks like a
bunch got accepted, but I didn't see it in:
https://www.armlinux.org.uk/developer/patches/section.php?section=20&page=132

>
> > ---
> > arch/arm/kernel/relocate_kernel.S | 8 ++++----
> > 1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/arm/kernel/relocate_kernel.S b/arch/arm/kernel/relocate_kernel.S
> > index 7eaa2ae7aff5..72a08786e16e 100644
> > --- a/arch/arm/kernel/relocate_kernel.S
> > +++ b/arch/arm/kernel/relocate_kernel.S
> > @@ -25,26 +25,26 @@ ENTRY(relocate_new_kernel)
> > ldr r3, [r0],#4
> >
> > /* Is it a destination page. Put destination address to r4 */
> > - tst r3,#1,0
> > + tst r3,#1
> > beq 1f
> > bic r4,r3,#1
> > b 0b
> > 1:
> > /* Is it an indirection page */
> > - tst r3,#2,0
> > + tst r3,#2
> > beq 1f
> > bic r0,r3,#2
> > b 0b
> > 1:
> >
> > /* are we done ? */
> > - tst r3,#4,0
> > + tst r3,#4
> > beq 1f
> > b 2f
> >
> > 1:
> > /* is it source ? */
> > - tst r3,#8,0
> > + tst r3,#8
> > beq 0b
> > bic r3,r3,#8
> > mov r6,#1024
> > --
> > 2.25.0
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > [email protected]
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> >
>
> --
> RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
> FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
> According to speedtest.net: 11.9Mbps down 500kbps up
>
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--
Thanks,
~Nick Desaulniers