Blackfin: add support for TIF_NOTIFY_RESUME

Signed-off-by: Barry Song <barry.song@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

arch/blackfin/include/asm/thread_info.h

@@ -103,11 +103,13 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_RESTORE_SIGMASK	5	/* restore signal mask in do_signal() */
 #define TIF_FREEZE              6       /* is freezing for suspend */
 #define TIF_IRQ_SYNC            7       /* sync pipeline stage */
+#define TIF_NOTIFY_RESUME       8       /* callback before returning to user */
 
 /* as above, but as bit values */
 #define _TIF_SYSCALL_TRACE	(1<<TIF_SYSCALL_TRACE)
 #define _TIF_SIGPENDING		(1<<TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED	(1<<TIF_NEED_RESCHED)
+#define _TIF_NOTIFY_RESUME	(1<<TIF_NOTIFY_RESUME)
 #define _TIF_POLLING_NRFLAG	(1<<TIF_POLLING_NRFLAG)
 #define _TIF_RESTORE_SIGMASK	(1<<TIF_RESTORE_SIGMASK)
 #define _TIF_FREEZE             (1<<TIF_FREEZE)

arch/blackfin/kernel/signal.c

@@ -12,6 +12,7 @@
 #include <linux/binfmts.h>
 #include <linux/freezer.h>
 #include <linux/uaccess.h>
+#include <linux/tracehook.h>
 
 #include <asm/cacheflush.h>
 #include <asm/ucontext.h>
@@ -332,3 +333,20 @@ asmlinkage void do_signal(struct pt_regs *regs)
 		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 	}
 }
+
+/*
+ * notification of userspace execution resumption
+ */
+asmlinkage void do_notify_resume(struct pt_regs *regs)
+{
+	if (test_thread_flag(TIF_SIGPENDING) || test_thread_flag(TIF_RESTORE_SIGMASK))
+		do_signal(regs);
+
+	if (test_thread_flag(TIF_NOTIFY_RESUME)) {
+		clear_thread_flag(TIF_NOTIFY_RESUME);
+		tracehook_notify_resume(regs);
+		if (current->replacement_session_keyring)
+			key_replace_session_keyring();
+	}
+}
+

arch/blackfin/mach-common/entry.S

@@ -713,6 +713,8 @@ ENTRY(_system_call)
 	cc = BITTST(r7, TIF_RESTORE_SIGMASK);
 	if cc jump .Lsyscall_do_signals;
 	cc = BITTST(r7, TIF_SIGPENDING);
+	if cc jump .Lsyscall_do_signals;
+	cc = BITTST(r7, TIF_NOTIFY_RESUME);
 	if !cc jump .Lsyscall_really_exit;
 .Lsyscall_do_signals:
 	/* Reenable interrupts.  */
@@ -721,7 +723,7 @@ ENTRY(_system_call)
 
 	r0 = sp;
 	SP += -12;
-	call _do_signal;
+	call _do_notify_resume;
 	SP += 12;
 
 .Lsyscall_really_exit: