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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2010-03-25 14:51:51 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-03-26 11:33:57 +0100 |
| commit | ea8e61b7bbc4a2faef77db34eb2db2a2c2372ff6 (patch) | |
| tree | df2998225dc10245ce3d392576a724ab788e456c /arch/x86/kernel/step.c | |
| parent | x86, perf, bts, mm: Delete the never used BTS-ptrace code (diff) | |
| download | linux-ea8e61b7bbc4a2faef77db34eb2db2a2c2372ff6.tar.xz linux-ea8e61b7bbc4a2faef77db34eb2db2a2c2372ff6.zip | |
x86, ptrace: Fix block-step
Implement ptrace-block-step using TIF_BLOCKSTEP which will set
DEBUGCTLMSR_BTF when set for a task while preserving any other
DEBUGCTLMSR bits.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100325135414.017536066@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/step.c')
| -rw-r--r-- | arch/x86/kernel/step.c | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c index 7beba0769a8c..58de45ee08b6 100644 --- a/arch/x86/kernel/step.c +++ b/arch/x86/kernel/step.c @@ -169,9 +169,19 @@ static void enable_step(struct task_struct *child, bool block) * So noone should try to use debugger block stepping in a program * that uses user-mode single stepping itself. */ - if (!enable_single_step(child)) - return; - /* XXX */ + 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); + } } void user_enable_single_step(struct task_struct *child) @@ -189,7 +199,13 @@ void user_disable_single_step(struct task_struct *child) /* * Make sure block stepping (BTF) is disabled. */ - /* XXX */ + 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); + } /* Always clear TIF_SINGLESTEP... */ clear_tsk_thread_flag(child, TIF_SINGLESTEP); |