perf/core improvements and fixes:

. Add libdw DWARF post unwind support for ARM (Jean Pihet)
 
 . Consolidate types.h for ARM and ARM64 (Jean Pihet)
 
 . Fix possible null pointer dereference in session.c (Masanari Iida)
 
 . Cleanup, remove unused variables in map_switch_event() (Dongsheng Yang)
 
 . Remove nr_state_machine_bugs in perf latency (Dongsheng Yang)
 
 . Remove usage of trace_sched_wakeup(.success) (Peter Zijlstra)
 
 Signed-off-by: Jiri Olsa <jolsa@kernel.org>
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Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf into perf/core

Pull perf/core improvements and fixes from Jiri Olsa:

  * Add libdw DWARF post unwind support for ARM (Jean Pihet)

  * Consolidate types.h for ARM and ARM64 (Jean Pihet)

  * Fix possible null pointer dereference in session.c (Masanari Iida)

  * Cleanup, remove unused variables in map_switch_event() (Dongsheng Yang)

  * Remove nr_state_machine_bugs in perf latency (Dongsheng Yang)

  * Remove usage of trace_sched_wakeup(.success) (Peter Zijlstra)

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

tools/perf/Makefile.perf

@@ -411,7 +411,7 @@ LIB_OBJS += $(OUTPUT)tests/code-reading.o
 LIB_OBJS += $(OUTPUT)tests/sample-parsing.o
 LIB_OBJS += $(OUTPUT)tests/parse-no-sample-id-all.o
 ifndef NO_DWARF_UNWIND
-ifeq ($(ARCH),x86)
+ifeq ($(ARCH),$(filter $(ARCH),x86 arm))
 LIB_OBJS += $(OUTPUT)tests/dwarf-unwind.o
 endif
 endif

tools/perf/arch/arm/Makefile

@@ -5,3 +5,10 @@ endif
 ifndef NO_LIBUNWIND
 LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/unwind-libunwind.o
 endif
+ifndef NO_LIBDW_DWARF_UNWIND
+LIB_OBJS += $(OUTPUT)arch/$(ARCH)/util/unwind-libdw.o
+endif
+ifndef NO_DWARF_UNWIND
+LIB_OBJS += $(OUTPUT)arch/$(ARCH)/tests/regs_load.o
+LIB_OBJS += $(OUTPUT)arch/$(ARCH)/tests/dwarf-unwind.o
+endif

tools/perf/arch/arm/include/perf_regs.h

@@ -2,10 +2,15 @@
 #define ARCH_PERF_REGS_H
 
 #include <stdlib.h>
-#include "../../util/types.h"
+#include <linux/types.h>
 #include <asm/perf_regs.h>
 
+void perf_regs_load(u64 *regs);
+
 #define PERF_REGS_MASK	((1ULL << PERF_REG_ARM_MAX) - 1)
+#define PERF_REGS_MAX	PERF_REG_ARM_MAX
+#define PERF_SAMPLE_REGS_ABI	PERF_SAMPLE_REGS_ABI_32
+
 #define PERF_REG_IP	PERF_REG_ARM_PC
 #define PERF_REG_SP	PERF_REG_ARM_SP
 

tools/perf/arch/arm/tests/dwarf-unwind.c

@@ -0,0 +1,60 @@
+#include <string.h>
+#include "perf_regs.h"
+#include "thread.h"
+#include "map.h"
+#include "event.h"
+#include "tests/tests.h"
+
+#define STACK_SIZE 8192
+
+static int sample_ustack(struct perf_sample *sample,
+			 struct thread *thread, u64 *regs)
+{
+	struct stack_dump *stack = &sample->user_stack;
+	struct map *map;
+	unsigned long sp;
+	u64 stack_size, *buf;
+
+	buf = malloc(STACK_SIZE);
+	if (!buf) {
+		pr_debug("failed to allocate sample uregs data\n");
+		return -1;
+	}
+
+	sp = (unsigned long) regs[PERF_REG_ARM_SP];
+
+	map = map_groups__find(thread->mg, MAP__VARIABLE, (u64) sp);
+	if (!map) {
+		pr_debug("failed to get stack map\n");
+		free(buf);
+		return -1;
+	}
+
+	stack_size = map->end - sp;
+	stack_size = stack_size > STACK_SIZE ? STACK_SIZE : stack_size;
+
+	memcpy(buf, (void *) sp, stack_size);
+	stack->data = (char *) buf;
+	stack->size = stack_size;
+	return 0;
+}
+
+int test__arch_unwind_sample(struct perf_sample *sample,
+			     struct thread *thread)
+{
+	struct regs_dump *regs = &sample->user_regs;
+	u64 *buf;
+
+	buf = calloc(1, sizeof(u64) * PERF_REGS_MAX);
+	if (!buf) {
+		pr_debug("failed to allocate sample uregs data\n");
+		return -1;
+	}
+
+	perf_regs_load(buf);
+	regs->abi  = PERF_SAMPLE_REGS_ABI;
+	regs->regs = buf;
+	regs->mask = PERF_REGS_MASK;
+
+	return sample_ustack(sample, thread, buf);
+}

tools/perf/arch/arm/tests/regs_load.S

@@ -0,0 +1,58 @@
+#include <linux/linkage.h>
+
+#define R0 0x00
+#define R1 0x08
+#define R2 0x10
+#define R3 0x18
+#define R4 0x20
+#define R5 0x28
+#define R6 0x30
+#define R7 0x38
+#define R8 0x40
+#define R9 0x48
+#define SL 0x50
+#define FP 0x58
+#define IP 0x60
+#define SP 0x68
+#define LR 0x70
+#define PC 0x78
+
+/*
+ * Implementation of void perf_regs_load(u64 *regs);
+ *
+ * This functions fills in the 'regs' buffer from the actual registers values,
+ * in the way the perf built-in unwinding test expects them:
+ * - the PC at the time at the call to this function. Since this function
+ *   is called using a bl instruction, the PC value is taken from LR.
+ * The built-in unwinding test then unwinds the call stack from the dwarf
+ * information in unwind__get_entries.
+ *
+ * Notes:
+ * - the 8 bytes stride in the registers offsets comes from the fact
+ * that the registers are stored in an u64 array (u64 *regs),
+ * - the regs buffer needs to be zeroed before the call to this function,
+ * in this case using a calloc in dwarf-unwind.c.
+ */
+
+.text
+.type perf_regs_load,%function
+ENTRY(perf_regs_load)
+	str r0, [r0, #R0]
+	str r1, [r0, #R1]
+	str r2, [r0, #R2]
+	str r3, [r0, #R3]
+	str r4, [r0, #R4]
+	str r5, [r0, #R5]
+	str r6, [r0, #R6]
+	str r7, [r0, #R7]
+	str r8, [r0, #R8]
+	str r9, [r0, #R9]
+	str sl, [r0, #SL]
+	str fp, [r0, #FP]
+	str ip, [r0, #IP]
+	str sp, [r0, #SP]
+	str lr, [r0, #LR]
+	str lr, [r0, #PC]	// store pc as lr in order to skip the call
+	                        //  to this function
+	mov pc, lr
+ENDPROC(perf_regs_load)

tools/perf/arch/arm/util/unwind-libdw.c

@@ -0,0 +1,36 @@
+#include <elfutils/libdwfl.h>
+#include "../../util/unwind-libdw.h"
+#include "../../util/perf_regs.h"
+
+bool libdw__arch_set_initial_registers(Dwfl_Thread *thread, void *arg)
+{
+	struct unwind_info *ui = arg;
+	struct regs_dump *user_regs = &ui->sample->user_regs;
+	Dwarf_Word dwarf_regs[PERF_REG_ARM_MAX];
+
+#define REG(r) ({						\
+	Dwarf_Word val = 0;					\
+	perf_reg_value(&val, user_regs, PERF_REG_ARM_##r);	\
+	val;							\
+})
+
+	dwarf_regs[0]  = REG(R0);
+	dwarf_regs[1]  = REG(R1);
+	dwarf_regs[2]  = REG(R2);
+	dwarf_regs[3]  = REG(R3);
+	dwarf_regs[4]  = REG(R4);
+	dwarf_regs[5]  = REG(R5);
+	dwarf_regs[6]  = REG(R6);
+	dwarf_regs[7]  = REG(R7);
+	dwarf_regs[8]  = REG(R8);
+	dwarf_regs[9]  = REG(R9);
+	dwarf_regs[10] = REG(R10);
+	dwarf_regs[11] = REG(FP);
+	dwarf_regs[12] = REG(IP);
+	dwarf_regs[13] = REG(SP);
+	dwarf_regs[14] = REG(LR);
+	dwarf_regs[15] = REG(PC);
+
+	return dwfl_thread_state_registers(thread, 0, PERF_REG_ARM_MAX,
+					   dwarf_regs);
+}

tools/perf/arch/arm64/include/perf_regs.h

@@ -2,7 +2,7 @@
 #define ARCH_PERF_REGS_H
 
 #include <stdlib.h>
-#include "../../util/types.h"
+#include <linux/types.h>
 #include <asm/perf_regs.h>
 
 #define PERF_REGS_MASK	((1ULL << PERF_REG_ARM64_MAX) - 1)

tools/perf/builtin-sched.c

@@ -149,7 +149,6 @@ struct perf_sched {
 	unsigned long	 nr_runs;
 	unsigned long	 nr_timestamps;
 	unsigned long	 nr_unordered_timestamps;
-	unsigned long	 nr_state_machine_bugs;
 	unsigned long	 nr_context_switch_bugs;
 	unsigned long	 nr_events;
 	unsigned long	 nr_lost_chunks;
@@ -1007,17 +1006,12 @@ static int latency_wakeup_event(struct perf_sched *sched,
 				struct perf_sample *sample,
 				struct machine *machine)
 {
-	const u32 pid	  = perf_evsel__intval(evsel, sample, "pid"),
-		  success = perf_evsel__intval(evsel, sample, "success");
+	const u32 pid	  = perf_evsel__intval(evsel, sample, "pid");
 	struct work_atoms *atoms;
 	struct work_atom *atom;
 	struct thread *wakee;
 	u64 timestamp = sample->time;
 
-	/* Note for later, it may be interesting to observe the failing cases */
-	if (!success)
-		return 0;
-
 	wakee = machine__findnew_thread(machine, 0, pid);
 	atoms = thread_atoms_search(&sched->atom_root, wakee, &sched->cmp_pid);
 	if (!atoms) {
@@ -1037,12 +1031,18 @@ static int latency_wakeup_event(struct perf_sched *sched,
 	atom = list_entry(atoms->work_list.prev, struct work_atom, list);
 
 	/*
+	 * As we do not guarantee the wakeup event happens when
+	 * task is out of run queue, also may happen when task is
+	 * on run queue and wakeup only change ->state to TASK_RUNNING,
+	 * then we should not set the ->wake_up_time when wake up a
+	 * task which is on run queue.
+	 *
 	 * You WILL be missing events if you've recorded only
 	 * one CPU, or are only looking at only one, so don't
-	 * make useless noise.
+	 * skip in this case.
 	 */
 	if (sched->profile_cpu == -1 && atom->state != THREAD_SLEEPING)
-		sched->nr_state_machine_bugs++;
+		return 0;
 
 	sched->nr_timestamps++;
 	if (atom->sched_out_time > timestamp) {
@@ -1266,9 +1266,8 @@ static int process_sched_wakeup_event(struct perf_tool *tool,
 static int map_switch_event(struct perf_sched *sched, struct perf_evsel *evsel,
 			    struct perf_sample *sample, struct machine *machine)
 {
-	const u32 prev_pid = perf_evsel__intval(evsel, sample, "prev_pid"),
-		  next_pid = perf_evsel__intval(evsel, sample, "next_pid");
-	struct thread *sched_out __maybe_unused, *sched_in;
+	const u32 next_pid = perf_evsel__intval(evsel, sample, "next_pid");
+	struct thread *sched_in;
 	int new_shortname;
 	u64 timestamp0, timestamp = sample->time;
 	s64 delta;
@@ -1291,7 +1290,6 @@ static int map_switch_event(struct perf_sched *sched, struct perf_evsel *evsel,
 		return -1;
 	}
 
-	sched_out = machine__findnew_thread(machine, 0, prev_pid);
 	sched_in = machine__findnew_thread(machine, 0, next_pid);
 
 	sched->curr_thread[this_cpu] = sched_in;
@@ -1501,14 +1499,6 @@ static void print_bad_events(struct perf_sched *sched)
 			(double)sched->nr_lost_events/(double)sched->nr_events * 100.0,
 			sched->nr_lost_events, sched->nr_events, sched->nr_lost_chunks);
 	}
-	if (sched->nr_state_machine_bugs && sched->nr_timestamps) {
-		printf("  INFO: %.3f%% state machine bugs (%ld out of %ld)",
-			(double)sched->nr_state_machine_bugs/(double)sched->nr_timestamps*100.0,
-			sched->nr_state_machine_bugs, sched->nr_timestamps);
-		if (sched->nr_lost_events)
-			printf(" (due to lost events?)");
-		printf("\n");
-	}
 	if (sched->nr_context_switch_bugs && sched->nr_timestamps) {
 		printf("  INFO: %.3f%% context switch bugs (%ld out of %ld)",
 			(double)sched->nr_context_switch_bugs/(double)sched->nr_timestamps*100.0,

tools/perf/config/Makefile

@@ -40,11 +40,11 @@ ifeq ($(ARCH),arm64)
   LIBUNWIND_LIBS = -lunwind -lunwind-aarch64
 endif
 
-# So far there's only x86 libdw unwind support merged in perf.
+# So far there's only x86 and arm libdw unwind support merged in perf.
 # Disable it on all other architectures in case libdw unwind
 # support is detected in system. Add supported architectures
 # to the check.
-ifneq ($(ARCH),x86)
+ifneq ($(ARCH),$(filter $(ARCH),x86 arm))
   NO_LIBDW_DWARF_UNWIND := 1
 endif
 

tools/perf/tests/builtin-test.c

@@ -115,7 +115,7 @@ static struct test {
 		.desc = "Test parsing with no sample_id_all bit set",
 		.func = test__parse_no_sample_id_all,
 	},
-#if defined(__x86_64__) || defined(__i386__)
+#if defined(__x86_64__) || defined(__i386__) || defined(__arm__)
 #ifdef HAVE_DWARF_UNWIND_SUPPORT
 	{
 		.desc = "Test dwarf unwind",

tools/perf/tests/evsel-tp-sched.c

@@ -74,9 +74,6 @@ int test__perf_evsel__tp_sched_test(void)
 	if (perf_evsel__test_field(evsel, "prio", 4, true))
 		ret = -1;
 
-	if (perf_evsel__test_field(evsel, "success", 4, true))
-		ret = -1;
-
 	if (perf_evsel__test_field(evsel, "target_cpu", 4, true))
 		ret = -1;
 

tools/perf/tests/tests.h

@@ -45,7 +45,7 @@ int test__hists_filter(void);
 int test__mmap_thread_lookup(void);
 int test__thread_mg_share(void);
 
-#if defined(__x86_64__) || defined(__i386__)
+#if defined(__x86_64__) || defined(__i386__) || defined(__arm__)
 #ifdef HAVE_DWARF_UNWIND_SUPPORT
 struct thread;
 struct perf_sample;

tools/perf/util/session.c

@@ -1625,13 +1625,14 @@ out_delete_map:
 void perf_session__fprintf_info(struct perf_session *session, FILE *fp,
 				bool full)
 {
-	int fd = perf_data_file__fd(session->file);
 	struct stat st;
-	int ret;
+	int fd, ret;
 
 	if (session == NULL || fp == NULL)
 		return;
 
+	fd = perf_data_file__fd(session->file);
+
 	ret = fstat(fd, &st);
 	if (ret == -1)
 		return;