linux-kernel - Re: [PATCH 1/2] riscv: Fix building error in entry.S when CONFIG_RISCV_M

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Message-ID: <mhng-f7d831a1-d892-4c55-82e9-4427539f1337@palmerdabbelt-glaptop1>
Date:   Mon, 13 Jul 2020 13:11:05 -0700 (PDT)
From:   Palmer Dabbelt <palmer@...belt.com>
To:     greentime.hu@...ive.com
CC:     greentime.hu@...ive.com, linux-riscv@...ts.infradead.org,
        linux-kernel@...r.kernel.org, aou@...s.berkeley.edu,
        Paul Walmsley <paul.walmsley@...ive.com>, lkp@...el.com
Subject:     Re: [PATCH 1/2] riscv: Fix building error in entry.S when CONFIG_RISCV_M_MODE is enabled

On Mon, 13 Jul 2020 01:32:15 PDT (-0700), greentime.hu@...ive.com wrote:
> arch/riscv/kernel/entry.S: Assembler messages:
> arch/riscv/kernel/entry.S:106: Error: illegal operands `andi a0,s1,0x00001800'
>
> This building error is because of the SR_MPP value is too large to be used
> as an immediate value for andi. To fix this issue I use li to set the
> immediate value to t0, then it can use t0 and s1 to do and operation.

Thanks.  I guess I must have something wrong with my build tests, as it's
supposed to be building the NOMMU stuff.  I was just about to fix this up in
the patch, looks like I also lost my own Signed-off-by so I have to ammend it
anyway.

>
> Reported-by: kernel test robot <lkp@...el.com>
> Signed-off-by: Greentime Hu <greentime.hu@...ive.com>
> ---
>  arch/riscv/kernel/entry.S | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
> index 6ed579fc1073..000984695cd6 100644
> --- a/arch/riscv/kernel/entry.S
> +++ b/arch/riscv/kernel/entry.S
> @@ -99,7 +99,8 @@ _save_context:
>
>  #ifdef CONFIG_CONTEXT_TRACKING
>  	/* If previous state is in user mode, call context_tracking_user_exit. */
> -	andi a0, s1, SR_SPP
> +	li t0, SR_PP
> +	and a0, s1, t0
>  	bnez a0, skip_context_tracking
>  	call context_tracking_user_exit