linux-kernel - Re: [PATCH 08/15] powerpc/watchpoint: Disable all available watchpoints when !dawr_force

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Date:   Tue, 17 Mar 2020 11:35:22 +0100
From:   Christophe Leroy <christophe.leroy@....fr>
To:     Ravi Bangoria <ravi.bangoria@...ux.ibm.com>, mpe@...erman.id.au,
        mikey@...ling.org
Cc:     apopple@...ux.ibm.com, paulus@...ba.org, npiggin@...il.com,
        naveen.n.rao@...ux.vnet.ibm.com, peterz@...radead.org,
        jolsa@...nel.org, oleg@...hat.com, fweisbec@...il.com,
        mingo@...nel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 08/15] powerpc/watchpoint: Disable all available
 watchpoints when !dawr_force_enable



Le 09/03/2020 à 09:57, Ravi Bangoria a écrit :
> Instead of disabling only first watchpoint, disable all available
> watchpoints while clearing dawr_force_enable.
> 
> Signed-off-by: Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
> ---
>   arch/powerpc/kernel/dawr.c | 10 +++++++---
>   1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/dawr.c b/arch/powerpc/kernel/dawr.c
> index 311e51ee09f4..5c882f07ac7d 100644
> --- a/arch/powerpc/kernel/dawr.c
> +++ b/arch/powerpc/kernel/dawr.c
> @@ -50,9 +50,13 @@ int set_dawr(struct arch_hw_breakpoint *brk, int nr)
>   	return 0;
>   }
>   
> -static void set_dawr_cb(void *info)
> +static void disable_dawrs(void *info)

Can you explain a bit more what you do exactly ? Why do you change the 
name of the function and why the parameter becomes NULL ? And why it 
doens't take into account the parameter anymore ?

>   {
> -	set_dawr(info, 0);
> +	struct arch_hw_breakpoint null_brk = {0};
> +	int i;
> +
> +	for (i = 0; i < nr_wp_slots(); i++)
> +		set_dawr(&null_brk, i);
>   }
>   
>   static ssize_t dawr_write_file_bool(struct file *file,
> @@ -74,7 +78,7 @@ static ssize_t dawr_write_file_bool(struct file *file,
>   
>   	/* If we are clearing, make sure all CPUs have the DAWR cleared */
>   	if (!dawr_force_enable)
> -		smp_call_function(set_dawr_cb, &null_brk, 0);
> +		smp_call_function(disable_dawrs, NULL, 0);
>   
>   	return rc;
>   }
> 

Christophe