From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Oleg Nesterov , Srikar Dronamraju , Ben Hutchings , Rui Xiang Subject: [PATCH 3.4 139/214] ptrace/x86: Introduce set_task_blockstep() helper Date: Wed, 4 Jun 2014 21:18:22 -0700 Message-Id: <20140605041658.446516319@linuxfoundation.org> In-Reply-To: <20140605041639.638675216@linuxfoundation.org> References: <20140605041639.638675216@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Oleg Nesterov commit 848e8f5f0ad3169560c516fff6471be65f76e69f upstream. 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 Acked-by: Srikar Dronamraju Signed-off-by: Ben Hutchings Cc: Rui Xiang Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/step.c | 41 +++++++++++++++++++++-------------------- 1 file changed, 21 insertions(+), 20 deletions(-) --- a/arch/x86/kernel/step.c +++ b/arch/x86/kernel/step.c @@ -157,6 +157,21 @@ static int enable_single_step(struct tas 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_stru * 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 tas /* * 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);