Upgrade to 4.4.50-rt62

The current kernel is based on rt kernel v4.4.6-rt14. We will upgrade it
to 4.4.50-rt62.
The command to achieve it is:
a) Clone a git repo from
git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git

b) Get the diff between this two changesets:
git diff 640eca2901f3435e616157b11379d3223a44b391
705619beeea1b0b48219a683fd1a901a86fdaf5e

where the two commits are:
[yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only
640eca2901f3435e616157b11379d3223a44b391
640eca2901f3 v4.4.6-rt14
localversion-rt
[yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only
705619beeea1b0b48219a683fd1a901a86fdaf5e
705619beeea1 Linux 4.4.50-rt62
localversion-rt

c) One patch has been backported thus revert the patch before applying.

 filterdiff -p1 -x scripts/package/Makefile
~/tmp/v4.4.6-rt14-4.4.50-rt62.diff  |patch -p1 --dry-run

Upstream status: backport

Change-Id: I244d57a32f6066e5a5b9915f9fbf99e7bbca6e01
Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com>

7 files changed, 51 insertions, 46 deletions

diff --git a/kernel/include/asm-generic/bitops/lock.h b/kernel/include/asm-generic/bitops/lock.h
index c30266e94..8ef0ccbf8 100644
--- a/kernel/include/asm-generic/bitops/lock.h
+++ b/kernel/include/asm-generic/bitops/lock.h
@@ -29,16 +29,16 @@ do {					\
  * @nr: the bit to set
  * @addr: the address to start counting from
  *
- * This operation is like clear_bit_unlock, however it is not atomic.
- * It does provide release barrier semantics so it can be used to unlock
- * a bit lock, however it would only be used if no other CPU can modify
- * any bits in the memory until the lock is released (a good example is
- * if the bit lock itself protects access to the other bits in the word).
+ * A weaker form of clear_bit_unlock() as used by __bit_lock_unlock(). If all
+ * the bits in the word are protected by this lock some archs can use weaker
+ * ops to safely unlock.
+ *
+ * See for example x86's implementation.
  */
 #define __clear_bit_unlock(nr, addr)	\
 do {					\
-	smp_mb();			\
-	__clear_bit(nr, addr);		\
+	smp_mb__before_atomic();	\
+	clear_bit(nr, addr);		\
 } while (0)
 
 #endif /* _ASM_GENERIC_BITOPS_LOCK_H_ */
diff --git a/kernel/include/asm-generic/futex.h b/kernel/include/asm-generic/futex.h
index e56272c91..bf2d34c9d 100644
--- a/kernel/include/asm-generic/futex.h
+++ b/kernel/include/asm-generic/futex.h
@@ -108,11 +108,15 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
 	u32 val;
 
 	preempt_disable();
-	if (unlikely(get_user(val, uaddr) != 0))
+	if (unlikely(get_user(val, uaddr) != 0)) {
+		preempt_enable();
 		return -EFAULT;
+	}
 
-	if (val == oldval && unlikely(put_user(newval, uaddr) != 0))
+	if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) {
+		preempt_enable();
 		return -EFAULT;
+	}
 
 	*uval = val;
 	preempt_enable();
diff --git a/kernel/include/asm-generic/preempt.h b/kernel/include/asm-generic/preempt.h
index 5d8ffa3e6..c1cde3577 100644
--- a/kernel/include/asm-generic/preempt.h
+++ b/kernel/include/asm-generic/preempt.h
@@ -7,10 +7,10 @@
 
 static __always_inline int preempt_count(void)
 {
-	return current_thread_info()->preempt_count;
+	return READ_ONCE(current_thread_info()->preempt_count);
 }
 
-static __always_inline int *preempt_count_ptr(void)
+static __always_inline volatile int *preempt_count_ptr(void)
 {
 	return &current_thread_info()->preempt_count;
 }
diff --git a/kernel/include/asm-generic/qspinlock.h b/kernel/include/asm-generic/qspinlock.h
index e2aadbc71..1885fc44b 100644
--- a/kernel/include/asm-generic/qspinlock.h
+++ b/kernel/include/asm-generic/qspinlock.h
@@ -21,14 +21,33 @@
 #include <asm-generic/qspinlock_types.h>
 
 /**
+ * queued_spin_unlock_wait - wait until the _current_ lock holder releases the lock
+ * @lock : Pointer to queued spinlock structure
+ *
+ * There is a very slight possibility of live-lock if the lockers keep coming
+ * and the waiter is just unfortunate enough to not see any unlock state.
+ */
+#ifndef queued_spin_unlock_wait
+extern void queued_spin_unlock_wait(struct qspinlock *lock);
+#endif
+
+/**
  * queued_spin_is_locked - is the spinlock locked?
  * @lock: Pointer to queued spinlock structure
  * Return: 1 if it is locked, 0 otherwise
  */
+#ifndef queued_spin_is_locked
 static __always_inline int queued_spin_is_locked(struct qspinlock *lock)
 {
+	/*
+	 * See queued_spin_unlock_wait().
+	 *
+	 * Any !0 state indicates it is locked, even if _Q_LOCKED_VAL
+	 * isn't immediately observable.
+	 */
 	return atomic_read(&lock->val);
 }
+#endif
 
 /**
  * queued_spin_value_unlocked - is the spinlock structure unlocked?
@@ -98,19 +117,6 @@ static __always_inline void queued_spin_unlock(struct qspinlock *lock)
 }
 #endif
 
-/**
- * queued_spin_unlock_wait - wait until current lock holder releases the lock
- * @lock : Pointer to queued spinlock structure
- *
- * There is a very slight possibility of live-lock if the lockers keep coming
- * and the waiter is just unfortunate enough to not see any unlock state.
- */
-static inline void queued_spin_unlock_wait(struct qspinlock *lock)
-{
-	while (atomic_read(&lock->val) & _Q_LOCKED_MASK)
-		cpu_relax();
-}
-
 #ifndef virt_spin_lock
 static __always_inline bool virt_spin_lock(struct qspinlock *lock)
 {
diff --git a/kernel/include/asm-generic/siginfo.h b/kernel/include/asm-generic/siginfo.h
index 3d1a3af5c..a2508a8f9 100644
--- a/kernel/include/asm-generic/siginfo.h
+++ b/kernel/include/asm-generic/siginfo.h
@@ -17,21 +17,6 @@
 struct siginfo;
 void do_schedule_next_timer(struct siginfo *info);
 
-#ifndef HAVE_ARCH_COPY_SIGINFO
-
-#include <linux/string.h>
-
-static inline void copy_siginfo(struct siginfo *to, struct siginfo *from)
-{
-	if (from->si_code < 0)
-		memcpy(to, from, sizeof(*to));
-	else
-		/* _sigchld is currently the largest know union member */
-		memcpy(to, from, __ARCH_SI_PREAMBLE_SIZE + sizeof(from->_sifields._sigchld));
-}
-
-#endif
-
 extern int copy_siginfo_to_user(struct siginfo __user *to, const struct siginfo *from);
 
 #endif
diff --git a/kernel/include/asm-generic/uaccess.h b/kernel/include/asm-generic/uaccess.h
index 1bfa60295..32901d11f 100644
--- a/kernel/include/asm-generic/uaccess.h
+++ b/kernel/include/asm-generic/uaccess.h
@@ -230,14 +230,18 @@ extern int __put_user_bad(void) __attribute__((noreturn));
 	might_fault();						\
 	access_ok(VERIFY_READ, __p, sizeof(*ptr)) ?		\
 		__get_user((x), (__typeof__(*(ptr)) *)__p) :	\
-		-EFAULT;					\
+		((x) = (__typeof__(*(ptr)))0,-EFAULT);		\
 })
 
 #ifndef __get_user_fn
 static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
 {
-	size = __copy_from_user(x, ptr, size);
-	return size ? -EFAULT : size;
+	size_t n = __copy_from_user(x, ptr, size);
+	if (unlikely(n)) {
+		memset(x + (size - n), 0, n);
+		return -EFAULT;
+	}
+	return 0;
 }
 
 #define __get_user_fn(sz, u, k)	__get_user_fn(sz, u, k)
@@ -257,11 +261,13 @@ extern int __get_user_bad(void) __attribute__((noreturn));
 static inline long copy_from_user(void *to,
 		const void __user * from, unsigned long n)
 {
+	unsigned long res = n;
 	might_fault();
-	if (access_ok(VERIFY_READ, from, n))
-		return __copy_from_user(to, from, n);
-	else
-		return n;
+	if (likely(access_ok(VERIFY_READ, from, n)))
+		res = __copy_from_user(to, from, n);
+	if (unlikely(res))
+		memset(to + (n - res), 0, res);
+	return res;
 }
 
 static inline long copy_to_user(void __user *to,
diff --git a/kernel/include/asm-generic/vmlinux.lds.h b/kernel/include/asm-generic/vmlinux.lds.h
index c4bd0e2c1..ef2e8c97e 100644
--- a/kernel/include/asm-generic/vmlinux.lds.h
+++ b/kernel/include/asm-generic/vmlinux.lds.h
@@ -531,15 +531,19 @@
 
 #define INIT_TEXT							\
 	*(.init.text)							\
+	*(.text.startup)						\
 	MEM_DISCARD(init.text)
 
 #define EXIT_DATA							\
 	*(.exit.data)							\
+	*(.fini_array)							\
+	*(.dtors)							\
 	MEM_DISCARD(exit.data)						\
 	MEM_DISCARD(exit.rodata)
 
 #define EXIT_TEXT							\
 	*(.exit.text)							\
+	*(.text.exit)							\
 	MEM_DISCARD(exit.text)
 
 #define EXIT_CALL							\