On Tue, Jun 27, 2017 at 07:22:16PM +0000, Karl Beldan wrote:
> In this sequence the 'move' is assumed in the delay slot of the 'beq',
> but head.S is in reorder mode and the former gets pushed one 'nop'
> farther by the assembler.
>
> The corrected behavior made booting with an UHI supplied dtb erratic.
>
> Fixes: 15f37e158892 ("MIPS: store the appended dtb address in a variable")
> Cc: <stable@xxxxxxxxxxxxxxx>
> Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
> Cc: Jonas Gorski <jogo@xxxxxxxxxxx>
> Signed-off-by: Karl Beldan <karl.beldan+oss@xxxxxxxxx>
Ouch, nice catch.
Reviewed-by: James Hogan <james.hogan@xxxxxxxxxx>
Cheers
James
> ---
> arch/mips/kernel/head.S | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/mips/kernel/head.S b/arch/mips/kernel/head.S
> index cf05220..d1bb506 100644
> --- a/arch/mips/kernel/head.S
> +++ b/arch/mips/kernel/head.S
> @@ -106,8 +106,8 @@ NESTED(kernel_entry, 16, sp) # kernel entry point
> beq t0, t1, dtb_found
> #endif
> li t1, -2
> - beq a0, t1, dtb_found
> move t2, a1
> + beq a0, t1, dtb_found
>
> li t2, 0
> dtb_found:
> --
> 2.10.1
>
>
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