KEYS: Extend TIF_NOTIFY_RESUME to (almost) all architectures [try #6]

Implement TIF_NOTIFY_RESUME for most of those architectures in which isn't yet
available, and, whilst we're at it, have it call the appropriate tracehook.

After this patch, blackfin, m68k* and xtensa still lack support and need
alteration of assembly code to make it work.

Resume notification can then be used (by a later patch) to install a new
session keyring on the parent of a process.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>

cc: linux-arch@vger.kernel.org
Signed-off-by: James Morris <jmorris@namei.org>

2 files changed, 7 insertions, 0 deletions

diff --git a/arch/h8300/include/asm/thread_info.h b/arch/h8300/include/asm/thread_info.h
index 8bbc8b0ee45d..70e67e47d020 100644
--- a/arch/h8300/include/asm/thread_info.h
+++ b/arch/h8300/include/asm/thread_info.h
@@ -89,6 +89,7 @@ static inline struct thread_info *current_thread_info(void)
                                            TIF_NEED_RESCHED */
 #define TIF_MEMDIE              4
 #define TIF_RESTORE_SIGMASK     5       /* restore signal mask in do_signal() */
+#define TIF_NOTIFY_RESUME       6       /* callback before returning to user */
 #define TIF_FREEZE              16      /* is freezing for suspend */
 
 /* as above, but as bit values */
@@ -97,6 +98,7 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_NEED_RESCHED       (1<<TIF_NEED_RESCHED)
 #define _TIF_POLLING_NRFLAG     (1<<TIF_POLLING_NRFLAG)
 #define _TIF_RESTORE_SIGMASK    (1<<TIF_RESTORE_SIGMASK)
+#define _TIF_NOTIFY_RESUME      (1 << TIF_NOTIFY_RESUME)
 #define _TIF_FREEZE             (1<<TIF_FREEZE)
 
 #define _TIF_WORK_MASK          0x0000FFFE      /* work to do on interrupt/exception return */
diff --git a/arch/h8300/kernel/signal.c b/arch/h8300/kernel/signal.c
index cf3472f7389b..56b3ab7dbbb0 100644
--- a/arch/h8300/kernel/signal.c
+++ b/arch/h8300/kernel/signal.c
@@ -552,4 +552,9 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags)
 {
         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
                 do_signal(regs, NULL);
+
+        if (thread_info_flags & _TIF_NOTIFY_RESUME) {
+                clear_thread_flag(TIF_NOTIFY_RESUME);
+                tracehook_notify_resume(regs);
+        }
 }