7 files changed, 58 insertions, 38 deletions

diff --git a/arch/s390/oprofile/init.c b/arch/s390/oprofile/init.c
index a1e9d69a9c90..584b93674ea4 100644
--- a/arch/s390/oprofile/init.c
+++ b/arch/s390/oprofile/init.c
@@ -169,7 +169,7 @@ static ssize_t hw_interval_write(struct file *file, char const __user *buf,
         if (*offset)
                 return -EINVAL;
         retval = oprofilefs_ulong_from_user(&val, buf, count);
-        if (retval)
+        if (retval <= 0)
                 return retval;
         if (val < oprofile_min_interval)
                 oprofile_hw_interval = oprofile_min_interval;
@@ -212,7 +212,7 @@ static ssize_t hwsampler_zero_write(struct file *file, char const __user *buf,
                 return -EINVAL;
 
         retval = oprofilefs_ulong_from_user(&val, buf, count);
-        if (retval)
+        if (retval <= 0)
                 return retval;
         if (val != 0)
                 return -EINVAL;
@@ -243,7 +243,7 @@ static ssize_t hwsampler_kernel_write(struct file *file, char const __user *buf,
                 return -EINVAL;
 
         retval = oprofilefs_ulong_from_user(&val, buf, count);
-        if (retval)
+        if (retval <= 0)
                 return retval;
 
         if (val != 0 && val != 1)
@@ -278,7 +278,7 @@ static ssize_t hwsampler_user_write(struct file *file, char const __user *buf,
                 return -EINVAL;
 
         retval = oprofilefs_ulong_from_user(&val, buf, count);
-        if (retval)
+        if (retval <= 0)
                 return retval;
 
         if (val != 0 && val != 1)
@@ -317,7 +317,7 @@ static ssize_t timer_enabled_write(struct file *file, char const __user *buf,
                 return -EINVAL;
 
         retval = oprofilefs_ulong_from_user(&val, buf, count);
-        if (retval)
+        if (retval <= 0)
                 return retval;
 
         if (val != 0 && val != 1)
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index 7f2739e03e79..0d3d63afa76a 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -2008,6 +2008,7 @@ __init int intel_pmu_init(void)
                 break;
 
         case 28: /* Atom */
+        case 54: /* Cedariew */
                 memcpy(hw_cache_event_ids, atom_hw_cache_event_ids,
                        sizeof(hw_cache_event_ids));
 
diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
index 520b4265fcd2..da02e9cc3754 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
@@ -686,7 +686,8 @@ void intel_pmu_lbr_init_atom(void)
          * to have an operational LBR which can freeze
          * on PMU interrupt
          */
-        if (boot_cpu_data.x86_mask < 10) {
+        if (boot_cpu_data.x86_model == 28
+            && boot_cpu_data.x86_mask < 10) {
                 pr_cont("LBR disabled due to erratum");
                 return;
         }
diff --git a/arch/x86/kernel/microcode_core.c b/arch/x86/kernel/microcode_core.c
index 4873e62db6a1..9e5bcf1e2376 100644
--- a/arch/x86/kernel/microcode_core.c
+++ b/arch/x86/kernel/microcode_core.c
@@ -225,6 +225,9 @@ static ssize_t microcode_write(struct file *file, const char __user *buf,
         if (do_microcode_update(buf, len) == 0)
                 ret = (ssize_t)len;
 
+        if (ret > 0)
+                perf_check_microcode();
+
         mutex_unlock(&microcode_mutex);
         put_online_cpus();
 
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 7602ccb3f40e..33ed9d605f91 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -926,7 +926,7 @@ struct perf_event {
         struct hw_perf_event            hw;
 
         struct perf_event_context       *ctx;
-        struct file                     *filp;
+        atomic_long_t                   refcount;
 
         /*
          * These accumulate total time (in nanoseconds) that children
@@ -1296,6 +1296,7 @@ extern int perf_swevent_get_recursion_context(void);
 extern void perf_swevent_put_recursion_context(int rctx);
 extern void perf_event_enable(struct perf_event *event);
 extern void perf_event_disable(struct perf_event *event);
+extern int __perf_event_disable(void *info);
 extern void perf_event_task_tick(void);
 #else
 static inline void
@@ -1334,6 +1335,7 @@ static inline int  perf_swevent_get_recursion_context(void)		{ return -1; }
 static inline void perf_swevent_put_recursion_context(int rctx)         { }
 static inline void perf_event_enable(struct perf_event *event)          { }
 static inline void perf_event_disable(struct perf_event *event)         { }
+static inline int __perf_event_disable(void *info)                      { return -1; }
 static inline void perf_event_task_tick(void)                           { }
 #endif
 
diff --git a/kernel/events/core.c b/kernel/events/core.c
index b7935fcec7d9..7fee567153f0 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1253,7 +1253,7 @@ retry:
 /*
  * Cross CPU call to disable a performance event
  */
-static int __perf_event_disable(void *info)
+int __perf_event_disable(void *info)
 {
         struct perf_event *event = info;
         struct perf_event_context *ctx = event->ctx;
@@ -2935,12 +2935,12 @@ EXPORT_SYMBOL_GPL(perf_event_release_kernel);
 /*
  * Called when the last reference to the file is gone.
  */
-static int perf_release(struct inode *inode, struct file *file)
+static void put_event(struct perf_event *event)
 {
-        struct perf_event *event = file->private_data;
         struct task_struct *owner;
 
-        file->private_data = NULL;
+        if (!atomic_long_dec_and_test(&event->refcount))
+                return;
 
         rcu_read_lock();
         owner = ACCESS_ONCE(event->owner);
@@ -2975,7 +2975,13 @@ static int perf_release(struct inode *inode, struct file *file)
                 put_task_struct(owner);
         }
 
-        return perf_event_release_kernel(event);
+        perf_event_release_kernel(event);
+}
+
+static int perf_release(struct inode *inode, struct file *file)
+{
+        put_event(file->private_data);
+        return 0;
 }
 
 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
@@ -3227,7 +3233,7 @@ unlock:
 
 static const struct file_operations perf_fops;
 
-static struct perf_event *perf_fget_light(int fd, int *fput_needed)
+static struct file *perf_fget_light(int fd, int *fput_needed)
 {
         struct file *file;
 
@@ -3241,7 +3247,7 @@ static struct perf_event *perf_fget_light(int fd, int *fput_needed)
                 return ERR_PTR(-EBADF);
         }
 
-        return file->private_data;
+        return file;
 }
 
 static int perf_event_set_output(struct perf_event *event,
@@ -3273,19 +3279,21 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 
         case PERF_EVENT_IOC_SET_OUTPUT:
         {
+                struct file *output_file = NULL;
                 struct perf_event *output_event = NULL;
                 int fput_needed = 0;
                 int ret;
 
                 if (arg != -1) {
-                        output_event = perf_fget_light(arg, &fput_needed);
-                        if (IS_ERR(output_event))
-                                return PTR_ERR(output_event);
+                        output_file = perf_fget_light(arg, &fput_needed);
+                        if (IS_ERR(output_file))
+                                return PTR_ERR(output_file);
+                        output_event = output_file->private_data;
                 }
 
                 ret = perf_event_set_output(event, output_event);
                 if (output_event)
-                        fput_light(output_event->filp, fput_needed);
+                        fput_light(output_file, fput_needed);
 
                 return ret;
         }
@@ -5950,6 +5958,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
 
         mutex_init(&event->mmap_mutex);
 
+        atomic_long_set(&event->refcount, 1);
         event->cpu              = cpu;
         event->attr             = *attr;
         event->group_leader     = group_leader;
@@ -6260,12 +6269,12 @@ SYSCALL_DEFINE5(perf_event_open,
                 return event_fd;
 
         if (group_fd != -1) {
-                group_leader = perf_fget_light(group_fd, &fput_needed);
-                if (IS_ERR(group_leader)) {
-                        err = PTR_ERR(group_leader);
+                group_file = perf_fget_light(group_fd, &fput_needed);
+                if (IS_ERR(group_file)) {
+                        err = PTR_ERR(group_file);
                         goto err_fd;
                 }
-                group_file = group_leader->filp;
+                group_leader = group_file->private_data;
                 if (flags & PERF_FLAG_FD_OUTPUT)
                         output_event = group_leader;
                 if (flags & PERF_FLAG_FD_NO_GROUP)
@@ -6402,7 +6411,6 @@ SYSCALL_DEFINE5(perf_event_open,
                 put_ctx(gctx);
         }
 
-        event->filp = event_file;
         WARN_ON_ONCE(ctx->parent_ctx);
         mutex_lock(&ctx->mutex);
 
@@ -6496,7 +6504,6 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
                 goto err_free;
         }
 
-        event->filp = NULL;
         WARN_ON_ONCE(ctx->parent_ctx);
         mutex_lock(&ctx->mutex);
         perf_install_in_context(ctx, event, cpu);
@@ -6578,7 +6585,7 @@ static void sync_child_event(struct perf_event *child_event,
          * Release the parent event, if this was the last
          * reference to it.
          */
-        fput(parent_event->filp);
+        put_event(parent_event);
 }
 
 static void
@@ -6654,9 +6661,8 @@ static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
          *
          *   __perf_event_exit_task()
          *     sync_child_event()
-         *       fput(parent_event->filp)
-         *         perf_release()
-         *           mutex_lock(&ctx->mutex)
+         *       put_event()
+         *         mutex_lock(&ctx->mutex)
          *
          * But since its the parent context it won't be the same instance.
          */
@@ -6724,7 +6730,7 @@ static void perf_free_event(struct perf_event *event,
         list_del_init(&event->child_list);
         mutex_unlock(&parent->child_mutex);
 
-        fput(parent->filp);
+        put_event(parent);
 
         perf_group_detach(event);
         list_del_event(event, ctx);
@@ -6804,6 +6810,12 @@ inherit_event(struct perf_event *parent_event,
                                            NULL, NULL);
         if (IS_ERR(child_event))
                 return child_event;
+
+        if (!atomic_long_inc_not_zero(&parent_event->refcount)) {
+                free_event(child_event);
+                return NULL;
+        }
+
         get_ctx(child_ctx);
 
         /*
@@ -6845,14 +6857,6 @@ inherit_event(struct perf_event *parent_event,
         raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
 
         /*
-         * Get a reference to the parent filp - we will fput it
-         * when the child event exits. This is safe to do because
-         * we are in the parent and we know that the filp still
-         * exists and has a nonzero count:
-         */
-        atomic_long_inc(&parent_event->filp->f_count);
-
-        /*
          * Link this into the parent event's child list
          */
         WARN_ON_ONCE(parent_event->ctx->parent_ctx);
diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index bb38c4d3ee12..9a7b487c6fe2 100644
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -453,7 +453,16 @@ int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *att
         int old_type = bp->attr.bp_type;
         int err = 0;
 
-        perf_event_disable(bp);
+        /*
+         * modify_user_hw_breakpoint can be invoked with IRQs disabled and hence it
+         * will not be possible to raise IPIs that invoke __perf_event_disable.
+         * So call the function directly after making sure we are targeting the
+         * current task.
+         */
+        if (irqs_disabled() && bp->ctx && bp->ctx->task == current)
+                __perf_event_disable(bp);
+        else
+                perf_event_disable(bp);
 
         bp->attr.bp_addr = attr->bp_addr;
         bp->attr.bp_type = attr->bp_type;