linux-kernel - Re: [PATCH v4 13/13] powerpc/ptrace: move ptrace_triggered() into hw

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Message-ID: <4e528bf2-2b53-ae93-cdcc-0c80953f40f2@c-s.fr>
Date:   Thu, 27 Feb 2020 18:09:20 +0100
From:   Christophe Leroy <christophe.leroy@....fr>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>, mikey@...ling.org,
        Russell Currey <ruscur@...sell.cc>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH v4 13/13] powerpc/ptrace: move ptrace_triggered() into
 hw_breakpoint.c

Russel,

Le 27/02/2020 à 12:49, Christophe Leroy a écrit :
> ptrace_triggered() is declared in asm/hw_breakpoint.h and
> only needed when CONFIG_HW_BREAKPOINT is set, so move it
> into hw_breakpoint.c

My series v4 is definitely buggy (I included ptrace_decl.h instead 
instead of ptrace-decl.h), how can Snowpatch say build succeeded 
(https://patchwork.ozlabs.org/patch/1245807/) ?

It fails at least on pmac32_defconfig and ppc64_defconfig, see:

http://kisskb.ellerman.id.au/kisskb/head/d45c91cf5f83424b8f3989b7ead28c50d8d765a9/

Christophe

> 
> Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
> ---
> v4: removing inclusing of hw_breakpoint.h now. Previously it was done too early.
> ---
>   arch/powerpc/kernel/hw_breakpoint.c | 16 ++++++++++++++++
>   arch/powerpc/kernel/ptrace/ptrace.c | 19 -------------------
>   2 files changed, 16 insertions(+), 19 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
> index 2462cd7c565c..2c0be9d941cf 100644
> --- a/arch/powerpc/kernel/hw_breakpoint.c
> +++ b/arch/powerpc/kernel/hw_breakpoint.c
> @@ -427,3 +427,19 @@ void hw_breakpoint_pmu_read(struct perf_event *bp)
>   {
>   	/* TODO */
>   }
> +
> +void ptrace_triggered(struct perf_event *bp,
> +		      struct perf_sample_data *data, struct pt_regs *regs)
> +{
> +	struct perf_event_attr attr;
> +
> +	/*
> +	 * Disable the breakpoint request here since ptrace has defined a
> +	 * one-shot behaviour for breakpoint exceptions in PPC64.
> +	 * The SIGTRAP signal is generated automatically for us in do_dabr().
> +	 * We don't have to do anything about that here
> +	 */
> +	attr = bp->attr;
> +	attr.disabled = true;
> +	modify_user_hw_breakpoint(bp, &attr);
> +}
> diff --git a/arch/powerpc/kernel/ptrace/ptrace.c b/arch/powerpc/kernel/ptrace/ptrace.c
> index a44f6e5e05ff..f6e51be47c6e 100644
> --- a/arch/powerpc/kernel/ptrace/ptrace.c
> +++ b/arch/powerpc/kernel/ptrace/ptrace.c
> @@ -18,7 +18,6 @@
>   #include <linux/regset.h>
>   #include <linux/tracehook.h>
>   #include <linux/audit.h>
> -#include <linux/hw_breakpoint.h>
>   #include <linux/context_tracking.h>
>   #include <linux/syscalls.h>
>   
> @@ -31,24 +30,6 @@
>   
>   #include "ptrace-decl.h"
>   
> -#ifdef CONFIG_HAVE_HW_BREAKPOINT
> -void ptrace_triggered(struct perf_event *bp,
> -		      struct perf_sample_data *data, struct pt_regs *regs)
> -{
> -	struct perf_event_attr attr;
> -
> -	/*
> -	 * Disable the breakpoint request here since ptrace has defined a
> -	 * one-shot behaviour for breakpoint exceptions in PPC64.
> -	 * The SIGTRAP signal is generated automatically for us in do_dabr().
> -	 * We don't have to do anything about that here
> -	 */
> -	attr = bp->attr;
> -	attr.disabled = true;
> -	modify_user_hw_breakpoint(bp, &attr);
> -}
> -#endif /* CONFIG_HAVE_HW_BREAKPOINT */
> -
>   /*
>    * Called by kernel/ptrace.c when detaching..
>    *
>