From eee3af4a2c83a97fff107ddc445d9df6fded9ce4 Mon Sep 17 00:00:00 2001 From: Markus Metzger Date: Wed, 30 Jan 2008 13:31:09 +0100 Subject: x86, ptrace: support for branch trace store(BTS) Resend using different mail client Changes to the last version: - split implementation into two layers: ds/bts and ptrace - renamed TIF's - save/restore ds save area msr in __switch_to_xtra() - make block-stepping only look at BTF bit Signed-off-by: Markus Metzger Signed-off-by: Suresh Siddha Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/kernel/step.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) (limited to 'arch/x86/kernel/step.c') 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); -- cgit v1.2.3