[IA64] Synchronize RBS on PTRACE_ATTACH
When attaching to a stopped process, the RSE must be explicitly synced to user-space, so the debugger can read the correct values. Signed-off-by: Petr Tesarik <ptesarik@suse.cz> CC: Roland McGrath <roland@redhat.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
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@ -613,6 +613,63 @@ void ia64_sync_krbs(void)
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unw_init_running(do_sync_rbs, ia64_sync_kernel_rbs);
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}
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/*
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* After PTRACE_ATTACH, a thread's register backing store area in user
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* space is assumed to contain correct data whenever the thread is
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* stopped. arch_ptrace_stop takes care of this on tracing stops.
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* But if the child was already stopped for job control when we attach
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* to it, then it might not ever get into ptrace_stop by the time we
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* want to examine the user memory containing the RBS.
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*/
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void
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ptrace_attach_sync_user_rbs (struct task_struct *child)
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{
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int stopped = 0;
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struct unw_frame_info info;
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/*
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* If the child is in TASK_STOPPED, we need to change that to
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* TASK_TRACED momentarily while we operate on it. This ensures
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* that the child won't be woken up and return to user mode while
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* we are doing the sync. (It can only be woken up for SIGKILL.)
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*/
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read_lock(&tasklist_lock);
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if (child->signal) {
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spin_lock_irq(&child->sighand->siglock);
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if (child->state == TASK_STOPPED &&
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!test_and_set_tsk_thread_flag(child, TIF_RESTORE_RSE)) {
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tsk_set_notify_resume(child);
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child->state = TASK_TRACED;
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stopped = 1;
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}
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spin_unlock_irq(&child->sighand->siglock);
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}
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read_unlock(&tasklist_lock);
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if (!stopped)
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return;
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unw_init_from_blocked_task(&info, child);
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do_sync_rbs(&info, ia64_sync_user_rbs);
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/*
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* Now move the child back into TASK_STOPPED if it should be in a
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* job control stop, so that SIGCONT can be used to wake it up.
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*/
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read_lock(&tasklist_lock);
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if (child->signal) {
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spin_lock_irq(&child->sighand->siglock);
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if (child->state == TASK_TRACED &&
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(child->signal->flags & SIGNAL_STOP_STOPPED)) {
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child->state = TASK_STOPPED;
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}
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spin_unlock_irq(&child->sighand->siglock);
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}
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read_unlock(&tasklist_lock);
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}
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static inline int
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thread_matches (struct task_struct *thread, unsigned long addr)
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{
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@ -310,6 +310,10 @@ struct switch_stack {
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#define arch_ptrace_stop_needed(code, info) \
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(!test_thread_flag(TIF_RESTORE_RSE))
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extern void ptrace_attach_sync_user_rbs (struct task_struct *);
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#define arch_ptrace_attach(child) \
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ptrace_attach_sync_user_rbs(child)
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#endif /* !__KERNEL__ */
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/* pt_all_user_regs is used for PTRACE_GETREGS PTRACE_SETREGS */
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