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>

18 files changed, 64 insertions, 6 deletions

diff --git a/arch/alpha/include/asm/thread_info.h b/arch/alpha/include/asm/thread_info.h
index 60c83abfde70..5076a8860b18 100644
--- a/arch/alpha/include/asm/thread_info.h
+++ b/arch/alpha/include/asm/thread_info.h
@@ -75,6 +75,7 @@ register struct thread_info *__current_thread_info __asm__("$8");
 #define TIF_UAC_SIGBUS          7
 #define TIF_MEMDIE              8
 #define TIF_RESTORE_SIGMASK     9       /* restore signal mask in do_signal */
+#define TIF_NOTIFY_RESUME       10      /* callback before returning to user */
 #define TIF_FREEZE              16      /* is freezing for suspend */
 
 #define _TIF_SYSCALL_TRACE      (1<<TIF_SYSCALL_TRACE)
@@ -82,10 +83,12 @@ register struct thread_info *__current_thread_info __asm__("$8");
 #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)
 
 /* Work to do on interrupt/exception return.  */
-#define _TIF_WORK_MASK          (_TIF_SIGPENDING | _TIF_NEED_RESCHED)
+#define _TIF_WORK_MASK          (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
+                                 _TIF_NOTIFY_RESUME)
 
 /* Work to do on any return to userspace.  */
 #define _TIF_ALLWORK_MASK       (_TIF_WORK_MASK         \
diff --git a/arch/alpha/kernel/signal.c b/arch/alpha/kernel/signal.c
index df65eaa84c4c..04e17c1f0f1b 100644
--- a/arch/alpha/kernel/signal.c
+++ b/arch/alpha/kernel/signal.c
@@ -683,4 +683,9 @@ do_notify_resume(struct pt_regs *regs, struct switch_stack *sw,
 {
         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
                 do_signal(regs, sw, r0, r19);
+
+        if (thread_info_flags & _TIF_NOTIFY_RESUME) {
+                clear_thread_flag(TIF_NOTIFY_RESUME);
+                tracehook_notify_resume(regs);
+        }
 }
diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
index 73394e50cbca..d3a39b1e6c0f 100644
--- a/arch/arm/include/asm/thread_info.h
+++ b/arch/arm/include/asm/thread_info.h
@@ -130,11 +130,13 @@ extern void vfp_sync_state(struct thread_info *thread);
  *  TIF_SYSCALL_TRACE   - syscall trace active
  *  TIF_SIGPENDING      - signal pending
  *  TIF_NEED_RESCHED    - rescheduling necessary
+ *  TIF_NOTIFY_RESUME   - callback before returning to user
  *  TIF_USEDFPU         - FPU was used by this task this quantum (SMP)
  *  TIF_POLLING_NRFLAG  - true if poll_idle() is polling TIF_NEED_RESCHED
  */
 #define TIF_SIGPENDING          0
 #define TIF_NEED_RESCHED        1
+#define TIF_NOTIFY_RESUME       2       /* callback before returning to user */
 #define TIF_SYSCALL_TRACE       8
 #define TIF_POLLING_NRFLAG      16
 #define TIF_USING_IWMMXT        17
@@ -143,6 +145,7 @@ extern void vfp_sync_state(struct thread_info *thread);
 
 #define _TIF_SIGPENDING         (1 << TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED       (1 << TIF_NEED_RESCHED)
+#define _TIF_NOTIFY_RESUME      (1 << TIF_NOTIFY_RESUME)
 #define _TIF_SYSCALL_TRACE      (1 << TIF_SYSCALL_TRACE)
 #define _TIF_POLLING_NRFLAG     (1 << TIF_POLLING_NRFLAG)
 #define _TIF_USING_IWMMXT       (1 << TIF_USING_IWMMXT)
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 8c3de1a350b5..7813ab782fda 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -51,7 +51,7 @@ fast_work_pending:
 work_pending:
         tst     r1, #_TIF_NEED_RESCHED
         bne     work_resched
-        tst     r1, #_TIF_SIGPENDING
+        tst     r1, #_TIF_SIGPENDING|_TIF_NOTIFY_RESUME
         beq     no_work_pending
         mov     r0, sp                          @ 'regs'
         mov     r2, why                         @ 'syscall'
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index f6bc5d442782..13dec276927a 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -707,4 +707,9 @@ do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
 {
         if (thread_flags & _TIF_SIGPENDING)
                 do_signal(&current->blocked, regs, syscall);
+
+        if (thread_flags & _TIF_NOTIFY_RESUME) {
+                clear_thread_flag(TIF_NOTIFY_RESUME);
+                tracehook_notify_resume(regs);
+        }
 }
diff --git a/arch/avr32/include/asm/thread_info.h b/arch/avr32/include/asm/thread_info.h
index fc42de5ca209..fd0c5d7e9337 100644
--- a/arch/avr32/include/asm/thread_info.h
+++ b/arch/avr32/include/asm/thread_info.h
@@ -84,6 +84,7 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_MEMDIE              6
 #define TIF_RESTORE_SIGMASK     7       /* restore signal mask in do_signal */
 #define TIF_CPU_GOING_TO_SLEEP  8       /* CPU is entering sleep 0 mode */
+#define TIF_NOTIFY_RESUME       9       /* callback before returning to user */
 #define TIF_FREEZE              29
 #define TIF_DEBUG               30      /* debugging enabled */
 #define TIF_USERSPACE           31      /* true if FS sets userspace */
@@ -96,6 +97,7 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_MEMDIE             (1 << TIF_MEMDIE)
 #define _TIF_RESTORE_SIGMASK    (1 << TIF_RESTORE_SIGMASK)
 #define _TIF_CPU_GOING_TO_SLEEP (1 << TIF_CPU_GOING_TO_SLEEP)
+#define _TIF_NOTIFY_RESUME      (1 << TIF_NOTIFY_RESUME)
 #define _TIF_FREEZE             (1 << TIF_FREEZE)
 
 /* Note: The masks below must never span more than 16 bits! */
@@ -103,13 +105,15 @@ static inline struct thread_info *current_thread_info(void)
 /* work to do on interrupt/exception return */
 #define _TIF_WORK_MASK                          \
         ((1 << TIF_SIGPENDING)                  \
+         | _TIF_NOTIFY_RESUME                   \
          | (1 << TIF_NEED_RESCHED)              \
          | (1 << TIF_POLLING_NRFLAG)            \
          | (1 << TIF_BREAKPOINT)                \
          | (1 << TIF_RESTORE_SIGMASK))
 
 /* work to do on any return to userspace */
-#define _TIF_ALLWORK_MASK       (_TIF_WORK_MASK | (1 << TIF_SYSCALL_TRACE))
+#define _TIF_ALLWORK_MASK       (_TIF_WORK_MASK | (1 << TIF_SYSCALL_TRACE) | \
+                                 _TIF_NOTIFY_RESUME)
 /* work to do on return from debug mode */
 #define _TIF_DBGWORK_MASK       (_TIF_WORK_MASK & ~(1 << TIF_BREAKPOINT))
 
diff --git a/arch/avr32/kernel/entry-avr32b.S b/arch/avr32/kernel/entry-avr32b.S
index 009a80155d67..169268c40ae2 100644
--- a/arch/avr32/kernel/entry-avr32b.S
+++ b/arch/avr32/kernel/entry-avr32b.S
@@ -281,7 +281,7 @@ syscall_exit_work:
         ld.w    r1, r0[TI_flags]
         rjmp    1b
 
-2:      mov     r2, _TIF_SIGPENDING | _TIF_RESTORE_SIGMASK
+2:      mov     r2, _TIF_SIGPENDING | _TIF_RESTORE_SIGMASK | _TIF_NOTIFY_RESUME
         tst     r1, r2
         breq    3f
         unmask_interrupts
diff --git a/arch/avr32/kernel/signal.c b/arch/avr32/kernel/signal.c
index 27227561bad6..62d242e2d033 100644
--- a/arch/avr32/kernel/signal.c
+++ b/arch/avr32/kernel/signal.c
@@ -322,4 +322,9 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, struct thread_info *ti)
 
         if (ti->flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
                 do_signal(regs, &current->blocked, syscall);
+
+        if (ti->flags & _TIF_NOTIFY_RESUME) {
+                clear_thread_flag(TIF_NOTIFY_RESUME);
+                tracehook_notify_resume(regs);
+        }
 }
diff --git a/arch/cris/kernel/ptrace.c b/arch/cris/kernel/ptrace.c
index b326023baab2..4f06d7fb43dd 100644
--- a/arch/cris/kernel/ptrace.c
+++ b/arch/cris/kernel/ptrace.c
@@ -36,4 +36,9 @@ void do_notify_resume(int canrestart, struct pt_regs *regs,
         /* deal with pending signal delivery */
         if (thread_info_flags & _TIF_SIGPENDING)
                 do_signal(canrestart,regs);
+
+        if (thread_info_flags & _TIF_NOTIFY_RESUME) {
+                clear_thread_flag(TIF_NOTIFY_RESUME);
+                tracehook_notify_resume(regs);
+        }
 }
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);
+        }
 }
diff --git a/arch/m32r/include/asm/thread_info.h b/arch/m32r/include/asm/thread_info.h
index 07bb5bd00e2a..71578151a403 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 18124542a6eb..3220258be188 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);
 }
diff --git a/arch/mips/include/asm/thread_info.h b/arch/mips/include/asm/thread_info.h
index f9df720d2e40..01cc1630b66c 100644
--- a/arch/mips/include/asm/thread_info.h
+++ b/arch/mips/include/asm/thread_info.h
@@ -115,6 +115,7 @@ register struct thread_info *__current_thread_info __asm__("$28");
 #define TIF_NEED_RESCHED        2       /* rescheduling necessary */
 #define TIF_SYSCALL_AUDIT       3       /* syscall auditing active */
 #define TIF_SECCOMP             4       /* secure computing */
+#define TIF_NOTIFY_RESUME       5       /* callback before returning to user */
 #define TIF_RESTORE_SIGMASK     9       /* 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 */
@@ -139,6 +140,7 @@ register struct thread_info *__current_thread_info __asm__("$28");
 #define _TIF_NEED_RESCHED       (1<<TIF_NEED_RESCHED)
 #define _TIF_SYSCALL_AUDIT      (1<<TIF_SYSCALL_AUDIT)
 #define _TIF_SECCOMP            (1<<TIF_SECCOMP)
+#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/mips/kernel/signal.c b/arch/mips/kernel/signal.c
index 830c5ef9932b..a3d1015471de 100644
--- a/arch/mips/kernel/signal.c
+++ b/arch/mips/kernel/signal.c
@@ -700,4 +700,9 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
         /* deal with pending signal delivery */
         if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
                 do_signal(regs);
+
+        if (thread_info_flags & _TIF_NOTIFY_RESUME) {
+                clear_thread_flag(TIF_NOTIFY_RESUME);
+                tracehook_notify_resume(regs);
+        }
 }
diff --git a/arch/parisc/include/asm/thread_info.h b/arch/parisc/include/asm/thread_info.h
index 4ce0edfbe969..ac775a76bff7 100644
--- a/arch/parisc/include/asm/thread_info.h
+++ b/arch/parisc/include/asm/thread_info.h
@@ -59,6 +59,7 @@ struct thread_info {
 #define TIF_MEMDIE              5
 #define TIF_RESTORE_SIGMASK     6       /* restore saved signal mask */
 #define TIF_FREEZE              7       /* is freezing for suspend */
+#define TIF_NOTIFY_RESUME       8       /* callback before returning to user */
 
 #define _TIF_SYSCALL_TRACE      (1 << TIF_SYSCALL_TRACE)
 #define _TIF_SIGPENDING         (1 << TIF_SIGPENDING)
@@ -67,8 +68,9 @@ struct thread_info {
 #define _TIF_32BIT              (1 << TIF_32BIT)
 #define _TIF_RESTORE_SIGMASK    (1 << TIF_RESTORE_SIGMASK)
 #define _TIF_FREEZE             (1 << TIF_FREEZE)
+#define _TIF_NOTIFY_RESUME      (1 << TIF_NOTIFY_RESUME)
 
-#define _TIF_USER_WORK_MASK     (_TIF_SIGPENDING | \
+#define _TIF_USER_WORK_MASK     (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | \
                                  _TIF_NEED_RESCHED | _TIF_RESTORE_SIGMASK)
 
 #endif /* __KERNEL__ */
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index e552e547cb93..8c4712b74dc1 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -948,7 +948,7 @@ intr_check_sig:
         /* As above */
         mfctl   %cr30,%r1
         LDREG   TI_FLAGS(%r1),%r19
-        ldi     (_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK), %r20
+        ldi     (_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK|_TIF_NOTIFY_RESUME), %r20
         and,COND(<>)    %r19, %r20, %r0
         b,n     intr_restore    /* skip past if we've nothing to do */
 
diff --git a/arch/parisc/kernel/signal.c b/arch/parisc/kernel/signal.c
index f82544225e8e..b3bfc4326703 100644
--- a/arch/parisc/kernel/signal.c
+++ b/arch/parisc/kernel/signal.c
@@ -645,4 +645,9 @@ void do_notify_resume(struct pt_regs *regs, long in_syscall)
         if (test_thread_flag(TIF_SIGPENDING) ||
             test_thread_flag(TIF_RESTORE_SIGMASK))
                 do_signal(regs, in_syscall);
+
+        if (test_thread_flag(TIF_NOTIFY_RESUME)) {
+                clear_thread_flag(TIF_NOTIFY_RESUME);
+                tracehook_notify_resume(regs);
+        }
 }