linux-kernel - Re: [PATCH] ARM: OMAP2+: drop unnecessary adrl

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Message-ID: <CAKwvOdkyOW6RXTOCt1xMp2H+uH28ofByQOjyx776t8RDxTED2w@mail.gmail.com>
Date:   Wed, 1 Apr 2020 11:02:03 -0700
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     Stefan Agner <stefan@...er.ch>
Cc:     tony@...mide.com, Russell King <linux@...linux.org.uk>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        linux-omap@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
        clang-built-linux <clang-built-linux@...glegroups.com>
Subject: Re: [PATCH] ARM: OMAP2+: drop unnecessary adrl

On Sun, Mar 29, 2020 at 1:33 PM Stefan Agner <stefan@...er.ch> wrote:
>
> The adrl instruction has been introduced with commit dd31394779aa ("ARM:
> omap3: Thumb-2 compatibility for sleep34xx.S"), back when this assembly
> file was considerably longer. Today adr seems to have enough reach, even
> when inserting about 60 instructions between the use site and the label.
> Replace adrl with conventional adr instruction.
>
> This allows to build this file using Clang's integrated assembler (which
> does not support the adrl pseudo instruction).

Context: https://github.com/ClangBuiltLinux/linux/issues/430#issuecomment-476124724
If Peter says it's difficult to implement, I trust him.
Reviewed-by: Nick Desaulniers <ndesaulniers@...gle.com>

>
> Link: https://github.com/ClangBuiltLinux/linux/issues/430
> Signed-off-by: Stefan Agner <stefan@...er.ch>
> ---
>  arch/arm/mach-omap2/sleep34xx.S | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm/mach-omap2/sleep34xx.S b/arch/arm/mach-omap2/sleep34xx.S
> index ac1324c6453b..c4e97d35c310 100644
> --- a/arch/arm/mach-omap2/sleep34xx.S
> +++ b/arch/arm/mach-omap2/sleep34xx.S
> @@ -72,7 +72,7 @@ ENTRY(enable_omap3630_toggle_l2_on_restore)
>         stmfd   sp!, {lr}       @ save registers on stack
>         /* Setup so that we will disable and enable l2 */
>         mov     r1, #0x1
> -       adrl    r3, l2dis_3630_offset   @ may be too distant for plain adr
> +       adr     r3, l2dis_3630_offset
>         ldr     r2, [r3]                @ value for offset
>         str     r1, [r2, r3]            @ write to l2dis_3630
>         ldmfd   sp!, {pc}       @ restore regs and return
> --
> 2.25.1
>
> --
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-- 
Thanks,
~Nick Desaulniers