From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <peterz@infradead.org>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
Anton Arapov <anton@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Roland McGrath <roland@hack.frob.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/7] ptrace: Introduce set_task_blockstep() helper
Date: Fri, 7 Sep 2012 20:30:37 +0530 [thread overview]
Message-ID: <20120907150037.GP30238@linux.vnet.ibm.com> (raw)
In-Reply-To: <20120903152606.GA9068@redhat.com>
* Oleg Nesterov <oleg@redhat.com> [2012-09-03 17:26:06]:
> No functional changes, preparation for the next fix and for uprobes
> single-step fixes.
>
> Move the code playing with TIF_BLOCKSTEP/DEBUGCTLMSR_BTF into the
> new helper, set_task_blockstep().
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
> ---
> arch/x86/kernel/step.c | 41 +++++++++++++++++++++--------------------
> 1 files changed, 21 insertions(+), 20 deletions(-)
>
> diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c
> index c346d11..7a51498 100644
> --- a/arch/x86/kernel/step.c
> +++ b/arch/x86/kernel/step.c
> @@ -157,6 +157,21 @@ static int enable_single_step(struct task_struct *child)
> return 1;
> }
>
> +static void set_task_blockstep(struct task_struct *task, bool on)
> +{
> + unsigned long debugctl;
> +
> + debugctl = get_debugctlmsr();
> + if (on) {
> + debugctl |= DEBUGCTLMSR_BTF;
> + set_tsk_thread_flag(task, TIF_BLOCKSTEP);
> + } else {
> + debugctl &= ~DEBUGCTLMSR_BTF;
> + clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
> + }
> + update_debugctlmsr(debugctl);
> +}
> +
> /*
> * Enable single or block step.
> */
> @@ -169,19 +184,10 @@ static void enable_step(struct task_struct *child, bool block)
> * So no one should try to use debugger block stepping in a program
> * that uses user-mode single stepping itself.
> */
> - if (enable_single_step(child) && block) {
> - unsigned long debugctl = get_debugctlmsr();
> -
> - debugctl |= DEBUGCTLMSR_BTF;
> - update_debugctlmsr(debugctl);
> - set_tsk_thread_flag(child, TIF_BLOCKSTEP);
> - } else if (test_tsk_thread_flag(child, TIF_BLOCKSTEP)) {
> - unsigned long debugctl = get_debugctlmsr();
> -
> - debugctl &= ~DEBUGCTLMSR_BTF;
> - update_debugctlmsr(debugctl);
> - clear_tsk_thread_flag(child, TIF_BLOCKSTEP);
> - }
> + if (enable_single_step(child) && block)
> + set_task_blockstep(child, true);
> + else if (test_tsk_thread_flag(child, TIF_BLOCKSTEP))
> + set_task_blockstep(child, false);
> }
>
> void user_enable_single_step(struct task_struct *child)
> @@ -199,13 +205,8 @@ void user_disable_single_step(struct task_struct *child)
> /*
> * Make sure block stepping (BTF) is disabled.
> */
> - if (test_tsk_thread_flag(child, TIF_BLOCKSTEP)) {
> - unsigned long debugctl = get_debugctlmsr();
> -
> - debugctl &= ~DEBUGCTLMSR_BTF;
> - update_debugctlmsr(debugctl);
> - clear_tsk_thread_flag(child, TIF_BLOCKSTEP);
> - }
> + if (test_tsk_thread_flag(child, TIF_BLOCKSTEP))
> + set_task_blockstep(child, false);
>
> /* Always clear TIF_SINGLESTEP... */
> clear_tsk_thread_flag(child, TIF_SINGLESTEP);
> --
> 1.5.5.1
>
next prev parent reply other threads:[~2012-09-07 15:04 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-03 15:25 [PATCH 0/7] uprobes: single-step fixes Oleg Nesterov
2012-09-03 15:25 ` [PATCH 1/7] uprobes: Introduce arch_uprobe_enable/disable_step() Oleg Nesterov
2012-09-07 14:57 ` Srikar Dronamraju
2012-09-03 15:26 ` [PATCH 2/7] uprobes: x86: Implement x86 specific arch_uprobe_*_step Oleg Nesterov
2012-09-07 14:59 ` Srikar Dronamraju
2012-09-03 15:26 ` [PATCH 3/7] ptrace: Introduce set_task_blockstep() helper Oleg Nesterov
2012-09-07 15:00 ` Srikar Dronamraju [this message]
2012-09-03 15:26 ` [PATCH 4/7] ptrace: Partly fix set_task_blockstep()->update_debugctlmsr() logic Oleg Nesterov
2012-09-07 15:14 ` Srikar Dronamraju
2012-09-10 16:57 ` Sebastian Andrzej Siewior
2012-09-10 17:45 ` Peter Zijlstra
2012-09-10 17:27 ` Oleg Nesterov
2012-09-03 15:26 ` [PATCH 5/7] uprobes: Do not (ab)use TIF_SINGLESTEP/user_*_single_step() for single-stepping Oleg Nesterov
2012-09-07 15:11 ` Srikar Dronamraju
2012-09-07 15:50 ` Oleg Nesterov
2012-09-08 7:49 ` Srikar Dronamraju
2012-09-03 15:26 ` [PATCH 6/7] uprobes: Xol should send SIGTRAP if X86_EFLAGS_TF was set Oleg Nesterov
2012-09-12 12:08 ` Srikar Dronamraju
2012-09-12 14:45 ` Oleg Nesterov
2012-09-03 15:26 ` [PATCH 7/7] uprobes: Make arch_uprobe_task->saved_trap_nr "unsigned int" Oleg Nesterov
2012-09-12 12:27 ` Srikar Dronamraju
2012-09-08 17:06 ` [PATCH 0/7] uprobes: single-step fixes Oleg Nesterov
2012-09-12 12:33 ` Srikar Dronamraju
2012-09-08 17:06 ` [PATCH 8/7] uprobes: Fix arch_uprobe_disable_step() && UTASK_SSTEP_TRAPPED interaction Oleg Nesterov
2012-09-12 12:36 ` Srikar Dronamraju
2012-09-10 16:57 ` [PATCH 0/7] uprobes: single-step fixes Sebastian Andrzej Siewior
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