Re: [RFC PATCH v2 10/12] powerpc/ptrace: create ptrace_get_debugreg()

From: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
To: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	mikey@neuling.org, linux-kernel@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org,
	Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Subject: Re: [RFC PATCH v2 10/12] powerpc/ptrace: create ptrace_get_debugreg()
Date: Wed, 3 Jul 2019 08:33:42 +0530	[thread overview]
Message-ID: <6d47ed55-2b55-4c48-71cd-ef9d420a388d@linux.ibm.com> (raw)
In-Reply-To: <483ffd1c62d270d7079b41e1747f34d254390c24.1561735588.git.christophe.leroy@c-s.fr>


On 6/28/19 9:17 PM, Christophe Leroy wrote:
> Create ptrace_get_debugreg() to handle PTRACE_GET_DEBUGREG and
> reduce ifdef mess
> 
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
>  arch/powerpc/kernel/ptrace/ptrace-adv.c   |  9 +++++++++
>  arch/powerpc/kernel/ptrace/ptrace-decl.h  |  2 ++
>  arch/powerpc/kernel/ptrace/ptrace-noadv.c | 13 +++++++++++++
>  arch/powerpc/kernel/ptrace/ptrace.c       | 18 ++----------------
>  4 files changed, 26 insertions(+), 16 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/ptrace/ptrace-adv.c b/arch/powerpc/kernel/ptrace/ptrace-adv.c
> index 86e71fa6c5c8..dcc765940344 100644
> --- a/arch/powerpc/kernel/ptrace/ptrace-adv.c
> +++ b/arch/powerpc/kernel/ptrace/ptrace-adv.c
> @@ -83,6 +83,15 @@ void user_disable_single_step(struct task_struct *task)
>  	clear_tsk_thread_flag(task, TIF_SINGLESTEP);
>  }
>  
> +int ptrace_get_debugreg(struct task_struct *child, unsigned long addr,
> +			unsigned long __user *datalp)
> +{
> +	/* We only support one DABR and no IABRS at the moment */

No DABR / IABR in ptrace-adv.c

> +	if (addr > 0)
> +		return -EINVAL;
> +	return put_user(child->thread.debug.dac1, datalp);
> +}
> +
>  int ptrace_set_debugreg(struct task_struct *task, unsigned long addr, unsigned long data)
>  {
>  	/* For ppc64 we support one DABR and no IABR's at the moment (ppc64).
> diff --git a/arch/powerpc/kernel/ptrace/ptrace-decl.h b/arch/powerpc/kernel/ptrace/ptrace-decl.h
> index bdba09a87aea..4b4b6a1d508a 100644
> --- a/arch/powerpc/kernel/ptrace/ptrace-decl.h
> +++ b/arch/powerpc/kernel/ptrace/ptrace-decl.h
> @@ -176,6 +176,8 @@ int tm_cgpr32_set(struct task_struct *target, const struct user_regset *regset,
>  extern const struct user_regset_view user_ppc_native_view;
>  
>  /* ptrace-(no)adv */
> +int ptrace_get_debugreg(struct task_struct *child, unsigned long addr,
> +			unsigned long __user *datalp);
>  int ptrace_set_debugreg(struct task_struct *task, unsigned long addr, unsigned long data);
>  long ppc_set_hwdebug(struct task_struct *child, struct ppc_hw_breakpoint *bp_info);
>  long ppc_del_hwdebug(struct task_struct *child, long data);
> diff --git a/arch/powerpc/kernel/ptrace/ptrace-noadv.c b/arch/powerpc/kernel/ptrace/ptrace-noadv.c
> index 7db330c94538..985cca136f85 100644
> --- a/arch/powerpc/kernel/ptrace/ptrace-noadv.c
> +++ b/arch/powerpc/kernel/ptrace/ptrace-noadv.c
> @@ -64,6 +64,19 @@ void user_disable_single_step(struct task_struct *task)
>  	clear_tsk_thread_flag(task, TIF_SINGLESTEP);
>  }
>  
> +int ptrace_get_debugreg(struct task_struct *child, unsigned long addr,
> +			unsigned long __user *datalp)
> +{
> +	unsigned long dabr_fake;
> +
> +	/* We only support one DABR and no IABRS at the moment */
> +	if (addr > 0)
> +		return -EINVAL;
> +	dabr_fake = ((child->thread.hw_brk.address & (~HW_BRK_TYPE_DABR)) |
> +		     (child->thread.hw_brk.type & HW_BRK_TYPE_DABR));
> +	return put_user(dabr_fake, datalp);
> +}
> +
>  int ptrace_set_debugreg(struct task_struct *task, unsigned long addr, unsigned long data)
>  {
>  #ifdef CONFIG_HAVE_HW_BREAKPOINT
> diff --git a/arch/powerpc/kernel/ptrace/ptrace.c b/arch/powerpc/kernel/ptrace/ptrace.c
> index 377e0e541d5f..e789afae6f56 100644
> --- a/arch/powerpc/kernel/ptrace/ptrace.c
> +++ b/arch/powerpc/kernel/ptrace/ptrace.c
> @@ -211,23 +211,9 @@ long arch_ptrace(struct task_struct *child, long request,
>  		break;
>  	}
>  
> -	case PTRACE_GET_DEBUGREG: {
> -#ifndef CONFIG_PPC_ADV_DEBUG_REGS
> -		unsigned long dabr_fake;
> -#endif
> -		ret = -EINVAL;
> -		/* We only support one DABR and no IABRS at the moment */
> -		if (addr > 0)
> -			break;
> -#ifdef CONFIG_PPC_ADV_DEBUG_REGS
> -		ret = put_user(child->thread.debug.dac1, datalp);
> -#else
> -		dabr_fake = ((child->thread.hw_brk.address & (~HW_BRK_TYPE_DABR)) |
> -			     (child->thread.hw_brk.type & HW_BRK_TYPE_DABR));
> -		ret = put_user(dabr_fake, datalp);
> -#endif
> +	case PTRACE_GET_DEBUGREG:
> +		ret = ptrace_get_debugreg(child, addr, datalp);
>  		break;
> -	}
>  
>  	case PTRACE_SET_DEBUGREG:
>  		ret = ptrace_set_debugreg(child, addr, data);
> 

Otherwise,

Reviewed-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>