arm: use generic ptrace_resume code

Use the generic ptrace_resume code for PTRACE_SYSCALL, PTRACE_CONT,
PTRACE_KILL and PTRACE_SINGLESTEP.  This implies defining
arch_has_single_step in <asm/ptrace.h> and implementing the
user_enable_single_step and user_disable_single_step functions, which also
causes the breakpoint information to be cleared on fork, which could be
considered a bug fix.

Also the TIF_SYSCALL_TRACE thread flag is now cleared on PTRACE_KILL which
it previously wasn't and the single stepping disable only happens if the
tracee process isn't a zombie yet, which is consistent with all
architectures using the modern ptrace code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 14 deletions

diff --git a/arch/arm/kernel/ptrace.h b/arch/arm/kernel/ptrace.h
index def3b6184a79..3926605b82ea 100644
--- a/arch/arm/kernel/ptrace.h
+++ b/arch/arm/kernel/ptrace.h
@@ -14,20 +14,6 @@ extern void ptrace_set_bpt(struct task_struct *);
 extern void ptrace_break(struct task_struct *, struct pt_regs *);
 
 /*
- * make sure single-step breakpoint is gone.
- */
-static inline void single_step_disable(struct task_struct *task)
-{
-        task->ptrace &= ~PT_SINGLESTEP;
-        ptrace_cancel_bpt(task);
-}
-
-static inline void single_step_enable(struct task_struct *task)
-{
-        task->ptrace |= PT_SINGLESTEP;
-}
-
-/*
  * Send SIGTRAP if we're single-stepping
  */
 static inline void single_step_trap(struct task_struct *task)