diff options
Diffstat (limited to 'arch/x86/kernel/step.c')
| -rw-r--r-- | arch/x86/kernel/step.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c index f55c003f5b6..21ea22fda5f 100644 --- a/arch/x86/kernel/step.c +++ b/arch/x86/kernel/step.c @@ -169,9 +169,14 @@ static void enable_step(struct task_struct *child, bool block) */ if (enable_single_step(child) && block) { set_tsk_thread_flag(child, TIF_DEBUGCTLMSR); - write_debugctlmsr(child, DEBUGCTLMSR_BTF); - } else if (test_and_clear_tsk_thread_flag(child, TIF_DEBUGCTLMSR)) { - write_debugctlmsr(child, 0); + write_debugctlmsr(child, + child->thread.debugctlmsr | DEBUGCTLMSR_BTF); + } else { + write_debugctlmsr(child, + child->thread.debugctlmsr & ~TIF_DEBUGCTLMSR); + + if (!child->thread.debugctlmsr) + clear_tsk_thread_flag(child, TIF_DEBUGCTLMSR); } } @@ -190,8 +195,11 @@ void user_disable_single_step(struct task_struct *child) /* * Make sure block stepping (BTF) is disabled. */ - if (test_and_clear_tsk_thread_flag(child, TIF_DEBUGCTLMSR)) - write_debugctlmsr(child, 0); + write_debugctlmsr(child, + child->thread.debugctlmsr & ~TIF_DEBUGCTLMSR); + + if (!child->thread.debugctlmsr) + clear_tsk_thread_flag(child, TIF_DEBUGCTLMSR); /* Always clear TIF_SINGLESTEP... */ clear_tsk_thread_flag(child, TIF_SINGLESTEP); |