Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf updates from Ingo Molnar:
 "Features:

   - Add "uretprobes" - an optimization to uprobes, like kretprobes are
     an optimization to kprobes.  "perf probe -x file sym%return" now
     works like kretprobes.  By Oleg Nesterov.

   - Introduce per core aggregation in 'perf stat', from Stephane
     Eranian.

   - Add memory profiling via PEBS, from Stephane Eranian.

   - Event group view for 'annotate' in --stdio, --tui and --gtk, from
     Namhyung Kim.

   - Add support for AMD NB and L2I "uncore" counters, by Jacob Shin.

   - Add Ivy Bridge-EP uncore support, by Zheng Yan

   - IBM zEnterprise EC12 oprofile support patchlet from Robert Richter.

   - Add perf test entries for checking breakpoint overflow signal
     handler issues, from Jiri Olsa.

   - Add perf test entry for for checking number of EXIT events, from
     Namhyung Kim.

   - Add perf test entries for checking --cpu in record and stat, from
     Jiri Olsa.

   - Introduce perf stat --repeat forever, from Frederik Deweerdt.

   - Add --no-demangle to report/top, from Namhyung Kim.

   - PowerPC fixes plus a couple of cleanups/optimizations in uprobes
     and trace_uprobes, by Oleg Nesterov.

  Various fixes and refactorings:

   - Fix dependency of the python binding wrt libtraceevent, from
     Naohiro Aota.

   - Simplify some perf_evlist methods and to allow 'stat' to share code
     with 'record' and 'trace', by Arnaldo Carvalho de Melo.

   - Remove dead code in related to libtraceevent integration, from
     Namhyung Kim.

   - Revert "perf sched: Handle PERF_RECORD_EXIT events" to get 'perf
     sched lat' back working, by Arnaldo Carvalho de Melo

   - We don't use Newt anymore, just plain libslang, by Arnaldo Carvalho
     de Melo.

   - Kill a bunch of die() calls, from Namhyung Kim.

   - Fix build on non-glibc systems due to libio.h absence, from Cody P
     Schafer.

   - Remove some perf_session and tracing dead code, from David Ahern.

   - Honor parallel jobs, fix from Borislav Petkov

   - Introduce tools/lib/lk library, initially just removing duplication
     among tools/perf and tools/vm.  from Borislav Petkov

  ... and many more I missed to list, see the shortlog and git log for
  more details."

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (136 commits)
  perf/x86/intel/P4: Robistify P4 PMU types
  perf/x86/amd: Fix AMD NB and L2I "uncore" support
  perf/x86/amd: Remove old-style NB counter support from perf_event_amd.c
  perf/x86: Check all MSRs before passing hw check
  perf/x86/amd: Add support for AMD NB and L2I "uncore" counters
  perf/x86/intel: Add Ivy Bridge-EP uncore support
  perf/x86/intel: Fix SNB-EP CBO and PCU uncore PMU filter management
  perf/x86: Avoid kfree() in CPU_{STARTING,DYING}
  uprobes/perf: Avoid perf_trace_buf_prepare/submit if ->perf_events is empty
  uprobes/tracing: Don't pass addr=ip to perf_trace_buf_submit()
  uprobes/tracing: Change create_trace_uprobe() to support uretprobes
  uprobes/tracing: Make seq_printf() code uretprobe-friendly
  uprobes/tracing: Make register_uprobe_event() paths uretprobe-friendly
  uprobes/tracing: Make uprobe_{trace,perf}_print() uretprobe-friendly
  uprobes/tracing: Introduce is_ret_probe() and uretprobe_dispatcher()
  uprobes/tracing: Introduce uprobe_{trace,perf}_print() helpers
  uprobes/tracing: Generalize struct uprobe_trace_entry_head
  uprobes/tracing: Kill the pointless local_save_flags/preempt_count calls
  uprobes/tracing: Kill the pointless seq_print_ip_sym() call
  uprobes/tracing: Kill the pointless task_pt_regs() calls
  ...

2 files changed, 146 insertions, 62 deletions

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 9e014582e763..711ca7d3e7f1 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -109,11 +109,6 @@ struct kretprobe_trace_entry_head {
         unsigned long           ret_ip;
 };
 
-struct uprobe_trace_entry_head {
-        struct trace_entry      ent;
-        unsigned long           ip;
-};
-
 /*
  * trace_flag_type is an enumeration that holds different
  * states when a trace occurs. These are:
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 8dad2a92dee9..32494fb0ee64 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -28,6 +28,18 @@
 
 #define UPROBE_EVENT_SYSTEM     "uprobes"
 
+struct uprobe_trace_entry_head {
+        struct trace_entry      ent;
+        unsigned long           vaddr[];
+};
+
+#define SIZEOF_TRACE_ENTRY(is_return)                   \
+        (sizeof(struct uprobe_trace_entry_head) +       \
+         sizeof(unsigned long) * (is_return ? 2 : 1))
+
+#define DATAOF_TRACE_ENTRY(entry, is_return)            \
+        ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return))
+
 struct trace_uprobe_filter {
         rwlock_t                rwlock;
         int                     nr_systemwide;
@@ -64,6 +76,8 @@ static DEFINE_MUTEX(uprobe_lock);
 static LIST_HEAD(uprobe_list);
 
 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
+static int uretprobe_dispatcher(struct uprobe_consumer *con,
+                                unsigned long func, struct pt_regs *regs);
 
 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
 {
@@ -77,11 +91,16 @@ static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
         return !filter->nr_systemwide && list_empty(&filter->perf_events);
 }
 
+static inline bool is_ret_probe(struct trace_uprobe *tu)
+{
+        return tu->consumer.ret_handler != NULL;
+}
+
 /*
  * Allocate new trace_uprobe and initialize it (including uprobes).
  */
 static struct trace_uprobe *
-alloc_trace_uprobe(const char *group, const char *event, int nargs)
+alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
 {
         struct trace_uprobe *tu;
 
@@ -106,6 +125,8 @@ alloc_trace_uprobe(const char *group, const char *event, int nargs)
 
         INIT_LIST_HEAD(&tu->list);
         tu->consumer.handler = uprobe_dispatcher;
+        if (is_ret)
+                tu->consumer.ret_handler = uretprobe_dispatcher;
         init_trace_uprobe_filter(&tu->filter);
         return tu;
 
@@ -180,7 +201,7 @@ end:
 
 /*
  * Argument syntax:
- *  - Add uprobe: p[:[GRP/]EVENT] PATH:SYMBOL[+offs] [FETCHARGS]
+ *  - Add uprobe: p|r[:[GRP/]EVENT] PATH:SYMBOL [FETCHARGS]
  *
  *  - Remove uprobe: -:[GRP/]EVENT
  */
@@ -192,20 +213,23 @@ static int create_trace_uprobe(int argc, char **argv)
         char buf[MAX_EVENT_NAME_LEN];
         struct path path;
         unsigned long offset;
-        bool is_delete;
+        bool is_delete, is_return;
         int i, ret;
 
         inode = NULL;
         ret = 0;
         is_delete = false;
+        is_return = false;
         event = NULL;
         group = NULL;
 
         /* argc must be >= 1 */
         if (argv[0][0] == '-')
                 is_delete = true;
+        else if (argv[0][0] == 'r')
+                is_return = true;
         else if (argv[0][0] != 'p') {
-                pr_info("Probe definition must be started with 'p' or '-'.\n");
+                pr_info("Probe definition must be started with 'p', 'r' or '-'.\n");
                 return -EINVAL;
         }
 
@@ -303,7 +327,7 @@ static int create_trace_uprobe(int argc, char **argv)
                 kfree(tail);
         }
 
-        tu = alloc_trace_uprobe(group, event, argc);
+        tu = alloc_trace_uprobe(group, event, argc, is_return);
         if (IS_ERR(tu)) {
                 pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
                 ret = PTR_ERR(tu);
@@ -414,9 +438,10 @@ static void probes_seq_stop(struct seq_file *m, void *v)
 static int probes_seq_show(struct seq_file *m, void *v)
 {
         struct trace_uprobe *tu = v;
+        char c = is_ret_probe(tu) ? 'r' : 'p';
         int i;
 
-        seq_printf(m, "p:%s/%s", tu->call.class->system, tu->call.name);
+        seq_printf(m, "%c:%s/%s", c, tu->call.class->system, tu->call.name);
         seq_printf(m, " %s:0x%p", tu->filename, (void *)tu->offset);
 
         for (i = 0; i < tu->nr_args; i++)
@@ -485,65 +510,81 @@ static const struct file_operations uprobe_profile_ops = {
         .release        = seq_release,
 };
 
-/* uprobe handler */
-static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
+static void uprobe_trace_print(struct trace_uprobe *tu,
+                                unsigned long func, struct pt_regs *regs)
 {
         struct uprobe_trace_entry_head *entry;
         struct ring_buffer_event *event;
         struct ring_buffer *buffer;
-        u8 *data;
-        int size, i, pc;
-        unsigned long irq_flags;
+        void *data;
+        int size, i;
         struct ftrace_event_call *call = &tu->call;
 
-        local_save_flags(irq_flags);
-        pc = preempt_count();
-
-        size = sizeof(*entry) + tu->size;
-
+        size = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
         event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
-                                                  size, irq_flags, pc);
+                                                  size + tu->size, 0, 0);
         if (!event)
-                return 0;
+                return;
 
         entry = ring_buffer_event_data(event);
-        entry->ip = instruction_pointer(task_pt_regs(current));
-        data = (u8 *)&entry[1];
+        if (is_ret_probe(tu)) {
+                entry->vaddr[0] = func;
+                entry->vaddr[1] = instruction_pointer(regs);
+                data = DATAOF_TRACE_ENTRY(entry, true);
+        } else {
+                entry->vaddr[0] = instruction_pointer(regs);
+                data = DATAOF_TRACE_ENTRY(entry, false);
+        }
+
         for (i = 0; i < tu->nr_args; i++)
                 call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
 
         if (!filter_current_check_discard(buffer, call, entry, event))
-                trace_buffer_unlock_commit(buffer, event, irq_flags, pc);
+                trace_buffer_unlock_commit(buffer, event, 0, 0);
+}
 
+/* uprobe handler */
+static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
+{
+        if (!is_ret_probe(tu))
+                uprobe_trace_print(tu, 0, regs);
         return 0;
 }
 
+static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
+                                struct pt_regs *regs)
+{
+        uprobe_trace_print(tu, func, regs);
+}
+
 /* Event entry printers */
 static enum print_line_t
 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
 {
-        struct uprobe_trace_entry_head *field;
+        struct uprobe_trace_entry_head *entry;
         struct trace_seq *s = &iter->seq;
         struct trace_uprobe *tu;
         u8 *data;
         int i;
 
-        field = (struct uprobe_trace_entry_head *)iter->ent;
+        entry = (struct uprobe_trace_entry_head *)iter->ent;
         tu = container_of(event, struct trace_uprobe, call.event);
 
-        if (!trace_seq_printf(s, "%s: (", tu->call.name))
-                goto partial;
-
-        if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
-                goto partial;
-
-        if (!trace_seq_puts(s, ")"))
-                goto partial;
+        if (is_ret_probe(tu)) {
+                if (!trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)", tu->call.name,
+                                        entry->vaddr[1], entry->vaddr[0]))
+                        goto partial;
+                data = DATAOF_TRACE_ENTRY(entry, true);
+        } else {
+                if (!trace_seq_printf(s, "%s: (0x%lx)", tu->call.name,
+                                        entry->vaddr[0]))
+                        goto partial;
+                data = DATAOF_TRACE_ENTRY(entry, false);
+        }
 
-        data = (u8 *)&field[1];
         for (i = 0; i < tu->nr_args; i++) {
                 if (!tu->args[i].type->print(s, tu->args[i].name,
-                                             data + tu->args[i].offset, field))
+                                             data + tu->args[i].offset, entry))
                         goto partial;
         }
 
@@ -595,16 +636,23 @@ static void probe_event_disable(struct trace_uprobe *tu, int flag)
 
 static int uprobe_event_define_fields(struct ftrace_event_call *event_call)
 {
-        int ret, i;
+        int ret, i, size;
         struct uprobe_trace_entry_head field;
-        struct trace_uprobe *tu = (struct trace_uprobe *)event_call->data;
+        struct trace_uprobe *tu = event_call->data;
 
-        DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
+        if (is_ret_probe(tu)) {
+                DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
+                DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
+                size = SIZEOF_TRACE_ENTRY(true);
+        } else {
+                DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
+                size = SIZEOF_TRACE_ENTRY(false);
+        }
         /* Set argument names as fields */
         for (i = 0; i < tu->nr_args; i++) {
                 ret = trace_define_field(event_call, tu->args[i].type->fmttype,
                                          tu->args[i].name,
-                                         sizeof(field) + tu->args[i].offset,
+                                         size + tu->args[i].offset,
                                          tu->args[i].type->size,
                                          tu->args[i].type->is_signed,
                                          FILTER_OTHER);
@@ -622,8 +670,13 @@ static int __set_print_fmt(struct trace_uprobe *tu, char *buf, int len)
         int i;
         int pos = 0;
 
-        fmt = "(%lx)";
-        arg = "REC->" FIELD_STRING_IP;
+        if (is_ret_probe(tu)) {
+                fmt = "(%lx <- %lx)";
+                arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
+        } else {
+                fmt = "(%lx)";
+                arg = "REC->" FIELD_STRING_IP;
+        }
 
         /* When len=0, we just calculate the needed length */
 
@@ -752,49 +805,68 @@ static bool uprobe_perf_filter(struct uprobe_consumer *uc,
         return ret;
 }
 
-/* uprobe profile handler */
-static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
+static void uprobe_perf_print(struct trace_uprobe *tu,
+                                unsigned long func, struct pt_regs *regs)
 {
         struct ftrace_event_call *call = &tu->call;
         struct uprobe_trace_entry_head *entry;
         struct hlist_head *head;
-        u8 *data;
-        int size, __size, i;
-        int rctx;
+        void *data;
+        int size, rctx, i;
 
-        if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
-                return UPROBE_HANDLER_REMOVE;
-
-        __size = sizeof(*entry) + tu->size;
-        size = ALIGN(__size + sizeof(u32), sizeof(u64));
-        size -= sizeof(u32);
+        size = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
+        size = ALIGN(size + tu->size + sizeof(u32), sizeof(u64)) - sizeof(u32);
         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
-                return 0;
+                return;
 
         preempt_disable();
+        head = this_cpu_ptr(call->perf_events);
+        if (hlist_empty(head))
+                goto out;
 
         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
         if (!entry)
                 goto out;
 
-        entry->ip = instruction_pointer(task_pt_regs(current));
-        data = (u8 *)&entry[1];
+        if (is_ret_probe(tu)) {
+                entry->vaddr[0] = func;
+                entry->vaddr[1] = instruction_pointer(regs);
+                data = DATAOF_TRACE_ENTRY(entry, true);
+        } else {
+                entry->vaddr[0] = instruction_pointer(regs);
+                data = DATAOF_TRACE_ENTRY(entry, false);
+        }
+
         for (i = 0; i < tu->nr_args; i++)
                 call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
 
-        head = this_cpu_ptr(call->perf_events);
-        perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head, NULL);
-
+        perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
  out:
         preempt_enable();
+}
+
+/* uprobe profile handler */
+static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
+{
+        if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
+                return UPROBE_HANDLER_REMOVE;
+
+        if (!is_ret_probe(tu))
+                uprobe_perf_print(tu, 0, regs);
         return 0;
 }
+
+static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
+                                struct pt_regs *regs)
+{
+        uprobe_perf_print(tu, func, regs);
+}
 #endif  /* CONFIG_PERF_EVENTS */
 
 static
 int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, void *data)
 {
-        struct trace_uprobe *tu = (struct trace_uprobe *)event->data;
+        struct trace_uprobe *tu = event->data;
 
         switch (type) {
         case TRACE_REG_REGISTER:
@@ -843,6 +915,23 @@ static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
         return ret;
 }
 
+static int uretprobe_dispatcher(struct uprobe_consumer *con,
+                                unsigned long func, struct pt_regs *regs)
+{
+        struct trace_uprobe *tu;
+
+        tu = container_of(con, struct trace_uprobe, consumer);
+
+        if (tu->flags & TP_FLAG_TRACE)
+                uretprobe_trace_func(tu, func, regs);
+
+#ifdef CONFIG_PERF_EVENTS
+        if (tu->flags & TP_FLAG_PROFILE)
+                uretprobe_perf_func(tu, func, regs);
+#endif
+        return 0;
+}
+
 static struct trace_event_functions uprobe_funcs = {
         .trace          = print_uprobe_event
 };