Upgrade to 4.4.50-rt62

The current kernel is based on rt kernel v4.4.6-rt14. We will upgrade it
to 4.4.50-rt62.
The command to achieve it is:
a) Clone a git repo from
git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git

b) Get the diff between this two changesets:
git diff 640eca2901f3435e616157b11379d3223a44b391
705619beeea1b0b48219a683fd1a901a86fdaf5e

where the two commits are:
[yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only
640eca2901f3435e616157b11379d3223a44b391
640eca2901f3 v4.4.6-rt14
localversion-rt
[yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only
705619beeea1b0b48219a683fd1a901a86fdaf5e
705619beeea1 Linux 4.4.50-rt62
localversion-rt

c) One patch has been backported thus revert the patch before applying.

 filterdiff -p1 -x scripts/package/Makefile
~/tmp/v4.4.6-rt14-4.4.50-rt62.diff  |patch -p1 --dry-run

Upstream status: backport

Change-Id: I244d57a32f6066e5a5b9915f9fbf99e7bbca6e01
Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com>

17 files changed, 118 insertions, 41 deletions

diff --git a/kernel/tools/perf/Documentation/perf-stat.txt b/kernel/tools/perf/Documentation/perf-stat.txt
index 4e074a660..90c3558c2 100644
--- a/kernel/tools/perf/Documentation/perf-stat.txt
+++ b/kernel/tools/perf/Documentation/perf-stat.txt
@@ -62,6 +62,14 @@ OPTIONS
 --scale::
 	scale/normalize counter values
 
+-d::
+--detailed::
+	print more detailed statistics, can be specified up to 3 times
+
+	   -d:          detailed events, L1 and LLC data cache
+        -d -d:     more detailed events, dTLB and iTLB events
+     -d -d -d:     very detailed events, adding prefetch events
+
 -r::
 --repeat=<n>::
 	repeat command and print average + stddev (max: 100). 0 means forever.
diff --git a/kernel/tools/perf/Makefile.perf b/kernel/tools/perf/Makefile.perf
index 0d19d5447..929a32ba1 100644
--- a/kernel/tools/perf/Makefile.perf
+++ b/kernel/tools/perf/Makefile.perf
@@ -420,7 +420,7 @@ $(LIBTRACEEVENT)-clean:
 	$(call QUIET_CLEAN, libtraceevent)
 	$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) O=$(OUTPUT) clean >/dev/null
 
-install-traceevent-plugins: $(LIBTRACEEVENT)
+install-traceevent-plugins: libtraceevent_plugins
 	$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) $(LIBTRACEEVENT_FLAGS) O=$(OUTPUT) install_plugins
 
 $(LIBAPI): fixdep FORCE
diff --git a/kernel/tools/perf/arch/x86/util/intel-pt.c b/kernel/tools/perf/arch/x86/util/intel-pt.c
index b02af064f..c53f78767 100644
--- a/kernel/tools/perf/arch/x86/util/intel-pt.c
+++ b/kernel/tools/perf/arch/x86/util/intel-pt.c
@@ -499,7 +499,7 @@ static int intel_pt_recording_options(struct auxtrace_record *itr,
 	struct intel_pt_recording *ptr =
 			container_of(itr, struct intel_pt_recording, itr);
 	struct perf_pmu *intel_pt_pmu = ptr->intel_pt_pmu;
-	bool have_timing_info;
+	bool have_timing_info, need_immediate = false;
 	struct perf_evsel *evsel, *intel_pt_evsel = NULL;
 	const struct cpu_map *cpus = evlist->cpus;
 	bool privileged = geteuid() == 0 || perf_event_paranoid() < 0;
@@ -653,6 +653,7 @@ static int intel_pt_recording_options(struct auxtrace_record *itr,
 				ptr->have_sched_switch = 3;
 			} else {
 				opts->record_switch_events = true;
+				need_immediate = true;
 				if (cpu_wide)
 					ptr->have_sched_switch = 3;
 				else
@@ -698,6 +699,9 @@ static int intel_pt_recording_options(struct auxtrace_record *itr,
 		tracking_evsel->attr.freq = 0;
 		tracking_evsel->attr.sample_period = 1;
 
+		if (need_immediate)
+			tracking_evsel->immediate = true;
+
 		/* In per-cpu case, always need the time of mmap events etc */
 		if (!cpu_map__empty(cpus)) {
 			perf_evsel__set_sample_bit(tracking_evsel, TIME);
diff --git a/kernel/tools/perf/tests/bpf.c b/kernel/tools/perf/tests/bpf.c
index ec16f7812..6ebfdee3e 100644
--- a/kernel/tools/perf/tests/bpf.c
+++ b/kernel/tools/perf/tests/bpf.c
@@ -146,7 +146,7 @@ prepare_bpf(void *obj_buf, size_t obj_buf_sz, const char *name)
 	return obj;
 }
 
-static int __test__bpf(int index)
+static int __test__bpf(int idx)
 {
 	int ret;
 	void *obj_buf;
@@ -154,27 +154,27 @@ static int __test__bpf(int index)
 	struct bpf_object *obj;
 
 	ret = test_llvm__fetch_bpf_obj(&obj_buf, &obj_buf_sz,
-				       bpf_testcase_table[index].prog_id,
+				       bpf_testcase_table[idx].prog_id,
 				       true);
 	if (ret != TEST_OK || !obj_buf || !obj_buf_sz) {
 		pr_debug("Unable to get BPF object, %s\n",
-			 bpf_testcase_table[index].msg_compile_fail);
-		if (index == 0)
+			 bpf_testcase_table[idx].msg_compile_fail);
+		if (idx == 0)
 			return TEST_SKIP;
 		else
 			return TEST_FAIL;
 	}
 
 	obj = prepare_bpf(obj_buf, obj_buf_sz,
-			  bpf_testcase_table[index].name);
+			  bpf_testcase_table[idx].name);
 	if (!obj) {
 		ret = TEST_FAIL;
 		goto out;
 	}
 
 	ret = do_test(obj,
-		      bpf_testcase_table[index].target_func,
-		      bpf_testcase_table[index].expect_result);
+		      bpf_testcase_table[idx].target_func,
+		      bpf_testcase_table[idx].expect_result);
 out:
 	bpf__clear();
 	return ret;
diff --git a/kernel/tools/perf/tests/llvm.c b/kernel/tools/perf/tests/llvm.c
index bc4cf507c..366e38ba8 100644
--- a/kernel/tools/perf/tests/llvm.c
+++ b/kernel/tools/perf/tests/llvm.c
@@ -50,7 +50,7 @@ static struct {
 int
 test_llvm__fetch_bpf_obj(void **p_obj_buf,
 			 size_t *p_obj_buf_sz,
-			 enum test_llvm__testcase index,
+			 enum test_llvm__testcase idx,
 			 bool force)
 {
 	const char *source;
@@ -59,11 +59,11 @@ test_llvm__fetch_bpf_obj(void **p_obj_buf,
 	char *tmpl_new = NULL, *clang_opt_new = NULL;
 	int err, old_verbose, ret = TEST_FAIL;
 
-	if (index >= __LLVM_TESTCASE_MAX)
+	if (idx >= __LLVM_TESTCASE_MAX)
 		return TEST_FAIL;
 
-	source = bpf_source_table[index].source;
-	desc = bpf_source_table[index].desc;
+	source = bpf_source_table[idx].source;
+	desc = bpf_source_table[idx].desc;
 
 	perf_config(perf_config_cb, NULL);
 
diff --git a/kernel/tools/perf/ui/browsers/hists.c b/kernel/tools/perf/ui/browsers/hists.c
index 81def6c3f..d80293864 100644
--- a/kernel/tools/perf/ui/browsers/hists.c
+++ b/kernel/tools/perf/ui/browsers/hists.c
@@ -684,7 +684,6 @@ static int __hpp__slsmg_color_printf(struct perf_hpp *hpp, const char *fmt, ...)
 	ret = scnprintf(hpp->buf, hpp->size, fmt, len, percent);
 	ui_browser__printf(arg->b, "%s", hpp->buf);
 
-	advance_hpp(hpp, ret);
 	return ret;
 }
 
@@ -2059,10 +2058,12 @@ skip_annotation:
 			 *
 			 * See hist_browser__show_entry.
 			 */
-			nr_options += add_script_opt(browser,
-						     &actions[nr_options],
-						     &options[nr_options],
-						     NULL, browser->selection->sym);
+			if (sort__has_sym && browser->selection->sym) {
+				nr_options += add_script_opt(browser,
+							     &actions[nr_options],
+							     &options[nr_options],
+							     NULL, browser->selection->sym);
+			}
 		}
 		nr_options += add_script_opt(browser, &actions[nr_options],
 					     &options[nr_options], NULL, NULL);
diff --git a/kernel/tools/perf/util/event.c b/kernel/tools/perf/util/event.c
index 8b10621b4..956187bf1 100644
--- a/kernel/tools/perf/util/event.c
+++ b/kernel/tools/perf/util/event.c
@@ -274,7 +274,7 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
 		strcpy(execname, "");
 
 		/* 00400000-0040c000 r-xp 00000000 fd:01 41038  /bin/cat */
-		n = sscanf(bf, "%"PRIx64"-%"PRIx64" %s %"PRIx64" %x:%x %u %s\n",
+		n = sscanf(bf, "%"PRIx64"-%"PRIx64" %s %"PRIx64" %x:%x %u %[^\n]\n",
 		       &event->mmap2.start, &event->mmap2.len, prot,
 		       &event->mmap2.pgoff, &event->mmap2.maj,
 		       &event->mmap2.min,
diff --git a/kernel/tools/perf/util/evlist.c b/kernel/tools/perf/util/evlist.c
index d1392194a..b4b96120f 100644
--- a/kernel/tools/perf/util/evlist.c
+++ b/kernel/tools/perf/util/evlist.c
@@ -1211,12 +1211,12 @@ void perf_evlist__set_maps(struct perf_evlist *evlist, struct cpu_map *cpus,
 	 */
 	if (cpus != evlist->cpus) {
 		cpu_map__put(evlist->cpus);
-		evlist->cpus = cpus;
+		evlist->cpus = cpu_map__get(cpus);
 	}
 
 	if (threads != evlist->threads) {
 		thread_map__put(evlist->threads);
-		evlist->threads = threads;
+		evlist->threads = thread_map__get(threads);
 	}
 
 	perf_evlist__propagate_maps(evlist);
diff --git a/kernel/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c b/kernel/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
index 9409d014b..71df7acf8 100644
--- a/kernel/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
+++ b/kernel/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
@@ -89,6 +89,7 @@ struct intel_pt_decoder {
 	bool pge;
 	bool have_tma;
 	bool have_cyc;
+	bool fixup_last_mtc;
 	uint64_t pos;
 	uint64_t last_ip;
 	uint64_t ip;
@@ -584,10 +585,31 @@ struct intel_pt_calc_cyc_to_tsc_info {
 	uint64_t        tsc_timestamp;
 	uint64_t        timestamp;
 	bool            have_tma;
+	bool            fixup_last_mtc;
 	bool            from_mtc;
 	double          cbr_cyc_to_tsc;
 };
 
+/*
+ * MTC provides a 8-bit slice of CTC but the TMA packet only provides the lower
+ * 16 bits of CTC. If mtc_shift > 8 then some of the MTC bits are not in the CTC
+ * provided by the TMA packet. Fix-up the last_mtc calculated from the TMA
+ * packet by copying the missing bits from the current MTC assuming the least
+ * difference between the two, and that the current MTC comes after last_mtc.
+ */
+static void intel_pt_fixup_last_mtc(uint32_t mtc, int mtc_shift,
+				    uint32_t *last_mtc)
+{
+	uint32_t first_missing_bit = 1U << (16 - mtc_shift);
+	uint32_t mask = ~(first_missing_bit - 1);
+
+	*last_mtc |= mtc & mask;
+	if (*last_mtc >= mtc) {
+		*last_mtc -= first_missing_bit;
+		*last_mtc &= 0xff;
+	}
+}
+
 static int intel_pt_calc_cyc_cb(struct intel_pt_pkt_info *pkt_info)
 {
 	struct intel_pt_decoder *decoder = pkt_info->decoder;
@@ -617,6 +639,11 @@ static int intel_pt_calc_cyc_cb(struct intel_pt_pkt_info *pkt_info)
 			return 0;
 
 		mtc = pkt_info->packet.payload;
+		if (decoder->mtc_shift > 8 && data->fixup_last_mtc) {
+			data->fixup_last_mtc = false;
+			intel_pt_fixup_last_mtc(mtc, decoder->mtc_shift,
+						&data->last_mtc);
+		}
 		if (mtc > data->last_mtc)
 			mtc_delta = mtc - data->last_mtc;
 		else
@@ -685,6 +712,7 @@ static int intel_pt_calc_cyc_cb(struct intel_pt_pkt_info *pkt_info)
 
 		data->ctc_delta = 0;
 		data->have_tma = true;
+		data->fixup_last_mtc = true;
 
 		return 0;
 
@@ -751,6 +779,7 @@ static void intel_pt_calc_cyc_to_tsc(struct intel_pt_decoder *decoder,
 		.tsc_timestamp  = decoder->tsc_timestamp,
 		.timestamp      = decoder->timestamp,
 		.have_tma       = decoder->have_tma,
+		.fixup_last_mtc = decoder->fixup_last_mtc,
 		.from_mtc       = from_mtc,
 		.cbr_cyc_to_tsc = 0,
 	};
@@ -1241,6 +1270,7 @@ static void intel_pt_calc_tma(struct intel_pt_decoder *decoder)
 	}
 	decoder->ctc_delta = 0;
 	decoder->have_tma = true;
+	decoder->fixup_last_mtc = true;
 	intel_pt_log("CTC timestamp " x64_fmt " last MTC %#x  CTC rem %#x\n",
 		     decoder->ctc_timestamp, decoder->last_mtc, ctc_rem);
 }
@@ -1255,6 +1285,12 @@ static void intel_pt_calc_mtc_timestamp(struct intel_pt_decoder *decoder)
 
 	mtc = decoder->packet.payload;
 
+	if (decoder->mtc_shift > 8 && decoder->fixup_last_mtc) {
+		decoder->fixup_last_mtc = false;
+		intel_pt_fixup_last_mtc(mtc, decoder->mtc_shift,
+					&decoder->last_mtc);
+	}
+
 	if (mtc > decoder->last_mtc)
 		mtc_delta = mtc - decoder->last_mtc;
 	else
@@ -1323,6 +1359,8 @@ static void intel_pt_calc_cyc_timestamp(struct intel_pt_decoder *decoder)
 			     timestamp, decoder->timestamp);
 	else
 		decoder->timestamp = timestamp;
+
+	decoder->timestamp_insn_cnt = 0;
 }
 
 /* Walk PSB+ packets when already in sync. */
diff --git a/kernel/tools/perf/util/intel-pt.c b/kernel/tools/perf/util/intel-pt.c
index 97f963a3d..89927b5be 100644
--- a/kernel/tools/perf/util/intel-pt.c
+++ b/kernel/tools/perf/util/intel-pt.c
@@ -238,7 +238,7 @@ static int intel_pt_get_trace(struct intel_pt_buffer *b, void *data)
 	}
 
 	queue = &ptq->pt->queues.queue_array[ptq->queue_nr];
-
+next:
 	buffer = auxtrace_buffer__next(queue, buffer);
 	if (!buffer) {
 		if (old_buffer)
@@ -261,9 +261,6 @@ static int intel_pt_get_trace(struct intel_pt_buffer *b, void *data)
 	    intel_pt_do_fix_overlap(ptq->pt, old_buffer, buffer))
 		return -ENOMEM;
 
-	if (old_buffer)
-		auxtrace_buffer__drop_data(old_buffer);
-
 	if (buffer->use_data) {
 		b->len = buffer->use_size;
 		b->buf = buffer->use_data;
@@ -273,6 +270,16 @@ static int intel_pt_get_trace(struct intel_pt_buffer *b, void *data)
 	}
 	b->ref_timestamp = buffer->reference;
 
+	/*
+	 * If in snapshot mode and the buffer has no usable data, get next
+	 * buffer and again check overlap against old_buffer.
+	 */
+	if (ptq->pt->snapshot_mode && !b->len)
+		goto next;
+
+	if (old_buffer)
+		auxtrace_buffer__drop_data(old_buffer);
+
 	if (!old_buffer || ptq->pt->sampling_mode || (ptq->pt->snapshot_mode &&
 						      !buffer->consecutive)) {
 		b->consecutive = false;
@@ -1127,7 +1134,7 @@ static int intel_pt_synth_transaction_sample(struct intel_pt_queue *ptq)
 		pr_err("Intel Processor Trace: failed to deliver transaction event, error %d\n",
 		       ret);
 
-	if (pt->synth_opts.callchain)
+	if (pt->synth_opts.last_branch)
 		intel_pt_reset_last_branch_rb(ptq);
 
 	return ret;
diff --git a/kernel/tools/perf/util/parse-events.c b/kernel/tools/perf/util/parse-events.c
index b48e87693..a35db828b 100644
--- a/kernel/tools/perf/util/parse-events.c
+++ b/kernel/tools/perf/util/parse-events.c
@@ -2101,11 +2101,11 @@ char *parse_events_formats_error_string(char *additional_terms)
 
 	/* valid terms */
 	if (additional_terms) {
-		if (!asprintf(&str, "valid terms: %s,%s",
-			      additional_terms, static_terms))
+		if (asprintf(&str, "valid terms: %s,%s",
+			     additional_terms, static_terms) < 0)
 			goto fail;
 	} else {
-		if (!asprintf(&str, "valid terms: %s", static_terms))
+		if (asprintf(&str, "valid terms: %s", static_terms) < 0)
 			goto fail;
 	}
 	return str;
diff --git a/kernel/tools/perf/util/pmu.c b/kernel/tools/perf/util/pmu.c
index e4b173dec..6f2a02794 100644
--- a/kernel/tools/perf/util/pmu.c
+++ b/kernel/tools/perf/util/pmu.c
@@ -283,13 +283,12 @@ static int pmu_aliases_parse(char *dir, struct list_head *head)
 {
 	struct dirent *evt_ent;
 	DIR *event_dir;
-	int ret = 0;
 
 	event_dir = opendir(dir);
 	if (!event_dir)
 		return -EINVAL;
 
-	while (!ret && (evt_ent = readdir(event_dir))) {
+	while ((evt_ent = readdir(event_dir))) {
 		char path[PATH_MAX];
 		char *name = evt_ent->d_name;
 		FILE *file;
@@ -305,17 +304,19 @@ static int pmu_aliases_parse(char *dir, struct list_head *head)
 
 		snprintf(path, PATH_MAX, "%s/%s", dir, name);
 
-		ret = -EINVAL;
 		file = fopen(path, "r");
-		if (!file)
-			break;
+		if (!file) {
+			pr_debug("Cannot open %s\n", path);
+			continue;
+		}
 
-		ret = perf_pmu__new_alias(head, dir, name, file);
+		if (perf_pmu__new_alias(head, dir, name, file) < 0)
+			pr_debug("Cannot set up %s\n", name);
 		fclose(file);
 	}
 
 	closedir(event_dir);
-	return ret;
+	return 0;
 }
 
 /*
diff --git a/kernel/tools/perf/util/setup.py b/kernel/tools/perf/util/setup.py
index 183310376..c8680984d 100644
--- a/kernel/tools/perf/util/setup.py
+++ b/kernel/tools/perf/util/setup.py
@@ -22,6 +22,7 @@ cflags = getenv('CFLAGS', '').split()
 # switch off several checks (need to be at the end of cflags list)
 cflags += ['-fno-strict-aliasing', '-Wno-write-strings', '-Wno-unused-parameter' ]
 
+src_perf  = getenv('srctree') + '/tools/perf'
 build_lib = getenv('PYTHON_EXTBUILD_LIB')
 build_tmp = getenv('PYTHON_EXTBUILD_TMP')
 libtraceevent = getenv('LIBTRACEEVENT')
@@ -30,6 +31,9 @@ libapikfs = getenv('LIBAPI')
 ext_sources = [f.strip() for f in file('util/python-ext-sources')
 				if len(f.strip()) > 0 and f[0] != '#']
 
+# use full paths with source files
+ext_sources = map(lambda x: '%s/%s' % (src_perf, x) , ext_sources)
+
 perf = Extension('perf',
 		  sources = ext_sources,
 		  include_dirs = ['util/include'],
diff --git a/kernel/tools/perf/util/stat.c b/kernel/tools/perf/util/stat.c
index 4a3a72cb5..6ce624cb7 100644
--- a/kernel/tools/perf/util/stat.c
+++ b/kernel/tools/perf/util/stat.c
@@ -311,6 +311,16 @@ int perf_stat_process_counter(struct perf_stat_config *config,
 
 	aggr->val = aggr->ena = aggr->run = 0;
 
+	/*
+	 * We calculate counter's data every interval,
+	 * and the display code shows ps->res_stats
+	 * avg value. We need to zero the stats for
+	 * interval mode, otherwise overall avg running
+	 * averages will be shown for each interval.
+	 */
+	if (config->interval)
+		init_stats(ps->res_stats);
+
 	if (counter->per_pkg)
 		zero_per_pkg(counter);
 
diff --git a/kernel/tools/perf/util/symbol-elf.c b/kernel/tools/perf/util/symbol-elf.c
index 475d88d0a..27ae382fe 100644
--- a/kernel/tools/perf/util/symbol-elf.c
+++ b/kernel/tools/perf/util/symbol-elf.c
@@ -1091,9 +1091,8 @@ new_symbol:
 	 * For misannotated, zeroed, ASM function sizes.
 	 */
 	if (nr > 0) {
-		if (!symbol_conf.allow_aliases)
-			symbols__fixup_duplicate(&dso->symbols[map->type]);
 		symbols__fixup_end(&dso->symbols[map->type]);
+		symbols__fixup_duplicate(&dso->symbols[map->type]);
 		if (kmap) {
 			/*
 			 * We need to fixup this here too because we create new
diff --git a/kernel/tools/perf/util/symbol.c b/kernel/tools/perf/util/symbol.c
index cd08027a6..520a32a12 100644
--- a/kernel/tools/perf/util/symbol.c
+++ b/kernel/tools/perf/util/symbol.c
@@ -151,6 +151,9 @@ void symbols__fixup_duplicate(struct rb_root *symbols)
 	struct rb_node *nd;
 	struct symbol *curr, *next;
 
+	if (symbol_conf.allow_aliases)
+		return;
+
 	nd = rb_first(symbols);
 
 	while (nd) {
@@ -1275,8 +1278,8 @@ int dso__load_kallsyms(struct dso *dso, const char *filename,
 	if (kallsyms__delta(map, filename, &delta))
 		return -1;
 
-	symbols__fixup_duplicate(&dso->symbols[map->type]);
 	symbols__fixup_end(&dso->symbols[map->type]);
+	symbols__fixup_duplicate(&dso->symbols[map->type]);
 
 	if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
 		dso->symtab_type = DSO_BINARY_TYPE__GUEST_KALLSYMS;
diff --git a/kernel/tools/perf/util/trace-event-scripting.c b/kernel/tools/perf/util/trace-event-scripting.c
index 9df61059a..a2fd6e79d 100644
--- a/kernel/tools/perf/util/trace-event-scripting.c
+++ b/kernel/tools/perf/util/trace-event-scripting.c
@@ -95,7 +95,8 @@ static void register_python_scripting(struct scripting_ops *scripting_ops)
 	if (err)
 		die("error registering py script extension");
 
-	scripting_context = malloc(sizeof(struct scripting_context));
+	if (scripting_context == NULL)
+		scripting_context = malloc(sizeof(*scripting_context));
 }
 
 #ifdef NO_LIBPYTHON
@@ -159,7 +160,8 @@ static void register_perl_scripting(struct scripting_ops *scripting_ops)
 	if (err)
 		die("error registering pl script extension");
 
-	scripting_context = malloc(sizeof(struct scripting_context));
+	if (scripting_context == NULL)
+		scripting_context = malloc(sizeof(*scripting_context));
 }
 
 #ifdef NO_LIBPERL