3 files changed, 46 insertions, 17 deletions

diff --git a/arch/s390/lib/Makefile b/arch/s390/lib/Makefile
index 97975ec7a274..cd54a1c352af 100644
--- a/arch/s390/lib/Makefile
+++ b/arch/s390/lib/Makefile
@@ -2,7 +2,7 @@
 # Makefile for s390-specific library files..
 #
 
-lib-y += delay.o string.o uaccess_std.o uaccess_pt.o
+lib-y += delay.o string.o uaccess_std.o uaccess_pt.o usercopy.o
 obj-$(CONFIG_32BIT) += div64.o qrnnd.o ucmpdi2.o
 lib-$(CONFIG_64BIT) += uaccess_mvcos.o
 lib-$(CONFIG_SMP) += spinlock.o
diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c
index cff327f109a8..91754ffb9203 100644
--- a/arch/s390/lib/spinlock.c
+++ b/arch/s390/lib/spinlock.c
@@ -43,16 +43,24 @@ void arch_spin_lock_wait(arch_spinlock_t *lp)
 {
         int count = spin_retry;
         unsigned int cpu = ~smp_processor_id();
+        unsigned int owner;
 
         while (1) {
-                if (count-- <= 0) {
-                        unsigned int owner = lp->owner_cpu;
-                        if (owner != 0)
-                                _raw_yield_cpu(~owner);
-                        count = spin_retry;
+                owner = lp->owner_cpu;
+                if (!owner || smp_vcpu_scheduled(~owner)) {
+                        for (count = spin_retry; count > 0; count--) {
+                                if (arch_spin_is_locked(lp))
+                                        continue;
+                                if (_raw_compare_and_swap(&lp->owner_cpu, 0,
+                                                          cpu) == 0)
+                                        return;
+                        }
+                        if (MACHINE_IS_LPAR)
+                                continue;
                 }
-                if (arch_spin_is_locked(lp))
-                        continue;
+                owner = lp->owner_cpu;
+                if (owner)
+                        _raw_yield_cpu(~owner);
                 if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0)
                         return;
         }
@@ -63,17 +71,27 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags)
 {
         int count = spin_retry;
         unsigned int cpu = ~smp_processor_id();
+        unsigned int owner;
 
         local_irq_restore(flags);
         while (1) {
-                if (count-- <= 0) {
-                        unsigned int owner = lp->owner_cpu;
-                        if (owner != 0)
-                                _raw_yield_cpu(~owner);
-                        count = spin_retry;
+                owner = lp->owner_cpu;
+                if (!owner || smp_vcpu_scheduled(~owner)) {
+                        for (count = spin_retry; count > 0; count--) {
+                                if (arch_spin_is_locked(lp))
+                                        continue;
+                                local_irq_disable();
+                                if (_raw_compare_and_swap(&lp->owner_cpu, 0,
+                                                          cpu) == 0)
+                                        return;
+                                local_irq_restore(flags);
+                        }
+                        if (MACHINE_IS_LPAR)
+                                continue;
                 }
-                if (arch_spin_is_locked(lp))
-                        continue;
+                owner = lp->owner_cpu;
+                if (owner)
+                        _raw_yield_cpu(~owner);
                 local_irq_disable();
                 if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0)
                         return;
@@ -100,8 +118,11 @@ EXPORT_SYMBOL(arch_spin_trylock_retry);
 void arch_spin_relax(arch_spinlock_t *lock)
 {
         unsigned int cpu = lock->owner_cpu;
-        if (cpu != 0)
-                _raw_yield_cpu(~cpu);
+        if (cpu != 0) {
+                if (MACHINE_IS_VM || MACHINE_IS_KVM ||
+                    !smp_vcpu_scheduled(~cpu))
+                        _raw_yield_cpu(~cpu);
+        }
 }
 EXPORT_SYMBOL(arch_spin_relax);
 
diff --git a/arch/s390/lib/usercopy.c b/arch/s390/lib/usercopy.c
new file mode 100644
index 000000000000..14b363fec8a2
--- /dev/null
+++ b/arch/s390/lib/usercopy.c
@@ -0,0 +1,8 @@
+#include <linux/module.h>
+#include <linux/bug.h>
+
+void copy_from_user_overflow(void)
+{
+        WARN(1, "Buffer overflow detected!\n");
+}
+EXPORT_SYMBOL(copy_from_user_overflow);