[PATCH] powerpc: fix regression in arch_initr_trap()

[Stefan Roese]

Hi Matt,

On 17.05.21 19:32, Matt Merhar wrote:
> The assembly output of the arch_initr_trap() function differed by a
> single byte after common.h was removed from traps.c:
> 
>   fff49a18 <arch_initr_trap>:
>   fff49a18:      94 21 ff f0     stwu    r1,-16(r1)
>   fff49a1c:      7c 08 02 a6     mflr    r0
>   fff49a20:      90 01 00 14     stw     r0,20(r1)
> -fff49a24:      80 62 00 44     lwz     r3,68(r2)
> +fff49a24:      80 62 00 38     lwz     r3,56(r2)
>   fff49a28:      4b ff 76 19     bl      fff41040 <trap_init>
>   fff49a2c:      80 01 00 14     lwz     r0,20(r1)
>   fff49a30:      38 60 00 00     li      r3,0
>   fff49a34:      38 21 00 10     addi    r1,r1,16
>   fff49a38:      7c 08 03 a6     mtlr    r0
> 
> This was causing a consistent hard lockup during the MMC read / loading
> of the QoriQ FMan firmware on a P2041RDB board.
> 
> Re-adding the header causes identical assembly to be emitted and allows
> the firmware loading and subsequent boot to succeed.
> 
> Fixes: 401d1c4f5d ("common: Drop asm/global_data.h from common header")
> Signed-off-by: Matt Merhar <mattmerhar at protonmail.com>

Did you try to investigate what exactly causes this difference in the
assembly code, when the header is not included? Re-adding this header
seems like "papering over" the real problem to me.

Thanks,
Stefan

> ---
> 
>   arch/powerpc/lib/traps.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/arch/powerpc/lib/traps.c b/arch/powerpc/lib/traps.c
> index c7bce82a44..ab8ca269a5 100644
> --- a/arch/powerpc/lib/traps.c
> +++ b/arch/powerpc/lib/traps.c
> @@ -4,6 +4,7 @@
>    * Wolfgang Denk, DENX Software Engineering, wd at denx.de.
>    */
>   
> +#include <common.h>
>   #include <init.h>
>   #include <asm/global_data.h>
>   
> 


Viele Grüße,
Stefan

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