linux-kernel - Re: [PATCH 2/2] MIPS: Watch: Avoid duplication of bits in mips_read_watch

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Date:   Fri, 5 Jan 2018 10:11:46 -0800
From:   David Daney <ddaney@...iumnetworks.com>
To:     Matt Redfearn <matt.redfearn@...s.com>, ralf@...ux-mips.org
Cc:     linux-mips@...ux-mips.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] MIPS: Watch: Avoid duplication of bits in
 mips_read_watch_registers

On 01/02/2018 03:31 AM, Matt Redfearn wrote:
> Currently the bits to be masked when watchhi is read is defined inline
> for each register. To avoid this, define the bits once and mask each
> register with that value.
> 
> Signed-off-by: Matt Redfearn <matt.redfearn@...s.com>

Acked-by: David Daney <david.daney@...ium.com>


> ---
> 
>   arch/mips/kernel/watch.c | 14 ++++++--------
>   1 file changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/mips/kernel/watch.c b/arch/mips/kernel/watch.c
> index 329d2209521d..0e61a5b7647f 100644
> --- a/arch/mips/kernel/watch.c
> +++ b/arch/mips/kernel/watch.c
> @@ -48,21 +48,19 @@ void mips_read_watch_registers(void)
>   {
>   	struct mips3264_watch_reg_state *watches =
>   		&current->thread.watch.mips3264;
> +	unsigned int watchhi_mask = MIPS_WATCHHI_MASK | MIPS_WATCHHI_IRW;
> +
>   	switch (current_cpu_data.watch_reg_use_cnt) {
>   	default:
>   		BUG();
>   	case 4:
> -		watches->watchhi[3] = (read_c0_watchhi3() &
> -				       (MIPS_WATCHHI_MASK | MIPS_WATCHHI_IRW));
> +		watches->watchhi[3] = (read_c0_watchhi3() & watchhi_mask);
>   	case 3:
> -		watches->watchhi[2] = (read_c0_watchhi2() &
> -				       (MIPS_WATCHHI_MASK | MIPS_WATCHHI_IRW));
> +		watches->watchhi[2] = (read_c0_watchhi2() & watchhi_mask);
>   	case 2:
> -		watches->watchhi[1] = (read_c0_watchhi1() &
> -				       (MIPS_WATCHHI_MASK | MIPS_WATCHHI_IRW));
> +		watches->watchhi[1] = (read_c0_watchhi1() & watchhi_mask);
>   	case 1:
> -		watches->watchhi[0] = (read_c0_watchhi0() &
> -				       (MIPS_WATCHHI_MASK | MIPS_WATCHHI_IRW));
> +		watches->watchhi[0] = (read_c0_watchhi0() & watchhi_mask);
>   	}
>   	if (current_cpu_data.watch_reg_use_cnt == 1 &&
>   	    (watches->watchhi[0] & MIPS_WATCHHI_IRW) == 0) {
>