From 848e8f5f0ad3169560c516fff6471be65f76e69f Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 3 Aug 2012 17:31:46 +0200 Subject: [PATCH] ptrace/x86: Introduce set_task_blockstep() helper 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 --- arch/x86/kernel/step.c | 41 +++++++++++++++++++++-------------------- 1 file changed, 21 insertions(+), 20 deletions(-) diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c index c346d116148..7a514986ca0 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);