sparc64: tracehook: TIF_NOTIFY_RESUME

This adds TIF_NOTIFY_RESUME support for sparc64.
When set, we call tracehook_notify_resume() on the way to user mode.
Signed-off-by: Roland McGrath <roland@redhat.com>

arch/sparc/include/asm/thread_info_64.h

@@ -219,7 +219,7 @@ register struct thread_info *current_thread_info_reg asm("g6");
  *	 nop
  */
 #define TIF_SYSCALL_TRACE	0	/* syscall trace active */
-/* flags bit 1 is available */
+#define TIF_NOTIFY_RESUME	1	/* callback before returning to user */
 #define TIF_SIGPENDING		2	/* signal pending */
 #define TIF_NEED_RESCHED	3	/* rescheduling necessary */
 #define TIF_PERFCTR		4	/* performance counters active */
@@ -239,6 +239,7 @@ register struct thread_info *current_thread_info_reg asm("g6");
 #define TIF_POLLING_NRFLAG	14
 
 #define _TIF_SYSCALL_TRACE	(1<<TIF_SYSCALL_TRACE)
+#define _TIF_NOTIFY_RESUME	(1<<TIF_NOTIFY_RESUME)
 #define _TIF_SIGPENDING		(1<<TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED	(1<<TIF_NEED_RESCHED)
 #define _TIF_PERFCTR		(1<<TIF_PERFCTR)
@@ -250,8 +251,9 @@ register struct thread_info *current_thread_info_reg asm("g6");
 #define _TIF_POLLING_NRFLAG	(1<<TIF_POLLING_NRFLAG)
 
 #define _TIF_USER_WORK_MASK	((0xff << TI_FLAG_WSAVED_SHIFT) | \
-				 (_TIF_SIGPENDING | \
-				  _TIF_NEED_RESCHED | _TIF_PERFCTR))
+				 _TIF_DO_NOTIFY_RESUME_MASK | \
+				 _TIF_NEED_RESCHED | _TIF_PERFCTR)
+#define _TIF_DO_NOTIFY_RESUME_MASK	(_TIF_NOTIFY_RESUME | _TIF_SIGPENDING)
 
 /*
  * Thread-synchronous status.

arch/sparc64/kernel/rtrap.S

@@ -46,7 +46,7 @@ __handle_user_windows:
 		wrpr			%g0, RTRAP_PSTATE_IRQOFF, %pstate
 		ldx			[%g6 + TI_FLAGS], %l0
 
-1:		andcc			%l0, _TIF_SIGPENDING, %g0
+1:		andcc			%l0, _TIF_DO_NOTIFY_RESUME_MASK, %g0
 		be,pt			%xcc, __handle_user_windows_continue
 		 nop
 		mov			%l5, %o1
@@ -86,7 +86,7 @@ __handle_perfctrs:
 		 wrpr			%g0, RTRAP_PSTATE, %pstate
 		wrpr			%g0, RTRAP_PSTATE_IRQOFF, %pstate
 		ldx			[%g6 + TI_FLAGS], %l0
-1:		andcc			%l0, _TIF_SIGPENDING, %g0
+1:		andcc			%l0, _TIF_DO_NOTIFY_RESUME_MASK, %g0
 
 		be,pt			%xcc, __handle_perfctrs_continue
 		 sethi			%hi(TSTATE_PEF), %o0
@@ -195,7 +195,7 @@ __handle_preemption_continue:
 		 andcc			%l1, %o0, %g0
 		andcc			%l0, _TIF_NEED_RESCHED, %g0
 		bne,pn			%xcc, __handle_preemption
-		 andcc			%l0, _TIF_SIGPENDING, %g0
+		 andcc			%l0, _TIF_DO_NOTIFY_RESUME_MASK, %g0
 		bne,pn			%xcc, __handle_signal
 __handle_signal_continue:
 		 ldub			[%g6 + TI_WSAVED], %o2

arch/sparc64/kernel/signal.c

@@ -17,6 +17,7 @@
 #include <linux/errno.h>
 #include <linux/wait.h>
 #include <linux/ptrace.h>
+#include <linux/tracehook.h>
 #include <linux/unistd.h>
 #include <linux/mm.h>
 #include <linux/tty.h>
@@ -605,4 +606,8 @@ void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long
 {
 	if (thread_info_flags & _TIF_SIGPENDING)
 		do_signal(regs, orig_i0);
+	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
+		clear_thread_flag(TIF_NOTIFY_RESUME);
+		tracehook_notify_resume(regs);
+	}
 }