3 files changed, 78 insertions, 2 deletions

diff --git a/arch/s390/include/asm/setup.h b/arch/s390/include/asm/setup.h
index 8bc87dcb10eb..2eb0c8a7b664 100644
--- a/arch/s390/include/asm/setup.h
+++ b/arch/s390/include/asm/setup.h
@@ -36,7 +36,7 @@
 #define MACHINE_FLAG_SCC        _BITUL(17)
 
 #define LPP_MAGIC               _BITUL(31)
-#define LPP_PFAULT_PID_MASK     _AC(0xffffffff, UL)
+#define LPP_PID_MASK            _AC(0xffffffff, UL)
 
 #ifndef __ASSEMBLY__
 
diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c
index dbb62c05805d..227b38bd82c9 100644
--- a/arch/s390/kernel/perf_cpum_sf.c
+++ b/arch/s390/kernel/perf_cpum_sf.c
@@ -15,6 +15,7 @@
 #include <linux/kernel_stat.h>
 #include <linux/perf_event.h>
 #include <linux/percpu.h>
+#include <linux/pid.h>
 #include <linux/notifier.h>
 #include <linux/export.h>
 #include <linux/slab.h>
@@ -615,6 +616,67 @@ static unsigned long hw_limit_rate(const struct hws_qsi_info_block *si,
                        si->min_sampl_rate, si->max_sampl_rate);
 }
 
+static u32 cpumsf_pid_type(struct perf_event *event,
+                           u32 pid, enum pid_type type)
+{
+        struct task_struct *tsk;
+
+        /* Idle process */
+        if (!pid)
+                goto out;
+
+        tsk = find_task_by_pid_ns(pid, &init_pid_ns);
+        pid = -1;
+        if (tsk) {
+                /*
+                 * Only top level events contain the pid namespace in which
+                 * they are created.
+                 */
+                if (event->parent)
+                        event = event->parent;
+                pid = __task_pid_nr_ns(tsk, type, event->ns);
+                /*
+                 * See also 1d953111b648
+                 * "perf/core: Don't report zero PIDs for exiting tasks".
+                 */
+                if (!pid && !pid_alive(tsk))
+                        pid = -1;
+        }
+out:
+        return pid;
+}
+
+static void cpumsf_output_event_pid(struct perf_event *event,
+                                    struct perf_sample_data *data,
+                                    struct pt_regs *regs)
+{
+        u32 pid;
+        struct perf_event_header header;
+        struct perf_output_handle handle;
+
+        /*
+         * Obtain the PID from the basic-sampling data entry and
+         * correct the data->tid_entry.pid value.
+         */
+        pid = data->tid_entry.pid;
+
+        /* Protect callchain buffers, tasks */
+        rcu_read_lock();
+
+        perf_prepare_sample(&header, data, event, regs);
+        if (perf_output_begin(&handle, event, header.size))
+                goto out;
+
+        /* Update the process ID (see also kernel/events/core.c) */
+        data->tid_entry.pid = cpumsf_pid_type(event, pid, __PIDTYPE_TGID);
+        data->tid_entry.tid = cpumsf_pid_type(event, pid, PIDTYPE_PID);
+
+        perf_output_sample(&handle, &header, data, event);
+        perf_output_end(&handle);
+out:
+        rcu_read_unlock();
+}
+
 static int __hw_perf_event_init(struct perf_event *event)
 {
         struct cpu_hw_sf *cpuhw;
@@ -748,6 +810,14 @@ static int __hw_perf_event_init(struct perf_event *event)
                                 break;
                 }
         }
+
+        /* If PID/TID sampling is active, replace the default overflow
+         * handler to extract and resolve the PIDs from the basic-sampling
+         * data entries.
+         */
+        if (event->attr.sample_type & PERF_SAMPLE_TID)
+                if (is_default_overflow_handler(event))
+                        event->overflow_handler = cpumsf_output_event_pid;
 out:
         return err;
 }
@@ -985,6 +1055,12 @@ static int perf_push_sample(struct perf_event *event,
                 break;
         }
 
+        /*
+         * Store the PID value from the sample-data-entry to be
+         * processed and resolved by cpumsf_output_event_pid().
+         */
+        data.tid_entry.pid = basic->hpp & LPP_PID_MASK;
+
         overflow = 0;
         if (perf_exclude_event(event, &regs, sde_regs))
                 goto out;
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 14654007dce4..93faeca52284 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -728,7 +728,7 @@ static void pfault_interrupt(struct ext_code ext_code,
                 return;
         inc_irq_stat(IRQEXT_PFL);
         /* Get the token (= pid of the affected task). */
-        pid = param64 & LPP_PFAULT_PID_MASK;
+        pid = param64 & LPP_PID_MASK;
         rcu_read_lock();
         tsk = find_task_by_pid_ns(pid, &init_pid_ns);
         if (tsk)