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

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Date:   Mon, 22 Jan 2018 21:18:07 +0000
From:   James Hogan <jhogan@...nel.org>
To:     Matt Redfearn <matt.redfearn@...s.com>
Cc:     ralf@...ux-mips.org, 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 Tue, Jan 02, 2018 at 11:31:22AM +0000, 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>

Reviewed-by: James Hogan <jhogan@...nel.org>

Cheers
James

> ---
> 
>  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) {
> -- 
> 2.7.4
> 
> 

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