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[IA64] Synchronize RBS on PTRACE_ATTACH

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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>
This commit is contained in:
Petr Tesarik 2007-12-12 15:24:25 +01:00 committed by Tony Luck
parent 3b2ce0b178
commit aa91a2e900
2 changed files with 61 additions and 0 deletions
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57
arch/ia64/kernel/ptrace.c
View file

@ -613,6 +613,63 @@ void ia64_sync_krbs(void)
unw_init_running(do_sync_rbs, ia64_sync_kernel_rbs);
}
/*
* After PTRACE_ATTACH, a thread's register backing store area in user
* space is assumed to contain correct data whenever the thread is
* stopped. arch_ptrace_stop takes care of this on tracing stops.
* But if the child was already stopped for job control when we attach
* to it, then it might not ever get into ptrace_stop by the time we
* want to examine the user memory containing the RBS.
*/
void
ptrace_attach_sync_user_rbs (struct task_struct *child)
{
int stopped = 0;
struct unw_frame_info info;
/*
* If the child is in TASK_STOPPED, we need to change that to
* TASK_TRACED momentarily while we operate on it. This ensures
* that the child won't be woken up and return to user mode while
* we are doing the sync. (It can only be woken up for SIGKILL.)
*/
read_lock(&tasklist_lock);
if (child->signal) {
spin_lock_irq(&child->sighand->siglock);
if (child->state == TASK_STOPPED &&
!test_and_set_tsk_thread_flag(child, TIF_RESTORE_RSE)) {
tsk_set_notify_resume(child);
child->state = TASK_TRACED;
stopped = 1;
}
spin_unlock_irq(&child->sighand->siglock);
}
read_unlock(&tasklist_lock);
if (!stopped)
return;
unw_init_from_blocked_task(&info, child);
do_sync_rbs(&info, ia64_sync_user_rbs);
/*
* Now move the child back into TASK_STOPPED if it should be in a
* job control stop, so that SIGCONT can be used to wake it up.
*/
read_lock(&tasklist_lock);
if (child->signal) {
spin_lock_irq(&child->sighand->siglock);
if (child->state == TASK_TRACED &&
(child->signal->flags & SIGNAL_STOP_STOPPED)) {
child->state = TASK_STOPPED;
}
spin_unlock_irq(&child->sighand->siglock);
}
read_unlock(&tasklist_lock);
}
static inline int
thread_matches (struct task_struct *thread, unsigned long addr)
{

4
include/asm-ia64/ptrace.h
View file

@ -310,6 +310,10 @@ struct switch_stack {
#define arch_ptrace_stop_needed(code, info) \
(!test_thread_flag(TIF_RESTORE_RSE))
extern void ptrace_attach_sync_user_rbs (struct task_struct *);
#define arch_ptrace_attach(child) \
ptrace_attach_sync_user_rbs(child)
#endif /* !__KERNEL__ */
/* pt_all_user_regs is used for PTRACE_GETREGS PTRACE_SETREGS */