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/m32r/include/asm/thread_info.h b/arch/m32r/include/asm/thread_info.h
index 07bb5bd00e2..71578151a40 100644
--- a/arch/m32r/include/asm/thread_info.h
+++ b/arch/m32r/include/asm/thread_info.h
@@ -149,6 +149,7 @@ static inline unsigned int get_thread_fault_code(void)
 #define TIF_NEED_RESCHED        2       /* rescheduling necessary */
 #define TIF_SINGLESTEP          3       /* restore singlestep on return to user mode */
 #define TIF_IRET                4       /* return with iret */
+#define TIF_NOTIFY_RESUME       5       /* callback before returning to user */
 #define TIF_RESTORE_SIGMASK     8       /* restore signal mask in do_signal() */
 #define TIF_USEDFPU             16      /* FPU was used by this task this quantum (SMP) */
 #define TIF_POLLING_NRFLAG      17      /* true if poll_idle() is polling TIF_NEED_RESCHED */
@@ -160,6 +161,7 @@ static inline unsigned int get_thread_fault_code(void)
 #define _TIF_NEED_RESCHED       (1<<TIF_NEED_RESCHED)
 #define _TIF_SINGLESTEP         (1<<TIF_SINGLESTEP)
 #define _TIF_IRET               (1<<TIF_IRET)
+#define _TIF_NOTIFY_RESUME      (1<<TIF_NOTIFY_RESUME)
 #define _TIF_RESTORE_SIGMASK    (1<<TIF_RESTORE_SIGMASK)
 #define _TIF_USEDFPU            (1<<TIF_USEDFPU)
 #define _TIF_POLLING_NRFLAG     (1<<TIF_POLLING_NRFLAG)
diff --git a/arch/m32r/kernel/signal.c b/arch/m32r/kernel/signal.c
index 18124542a6e..3220258be18 100644
--- a/arch/m32r/kernel/signal.c
+++ b/arch/m32r/kernel/signal.c
@@ -408,5 +408,10 @@ void do_notify_resume(struct pt_regs *regs, sigset_t *oldset,
         if (thread_info_flags & _TIF_SIGPENDING)
                 do_signal(regs,oldset);
 
+        if (thread_info_flags & _TIF_NOTIFY_RESUME) {
+                clear_thread_flag(TIF_NOTIFY_RESUME);
+                tracehook_notify_resume(regs);
+        }
+
         clear_thread_flag(TIF_IRET);
 }