1 files changed, 117 insertions, 9 deletions

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index b75b487574c..15dd0a9691c 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -12,6 +12,7 @@
 #include <stdbool.h>
 #include <symbol/kallsyms.h>
 #include "unwind.h"
+#include "linux/hash.h"
 
 static void dsos__init(struct dsos *dsos)
 {
@@ -1391,7 +1392,11 @@ static int add_callchain_ip(struct thread *thread,
 
 	al.filtered = 0;
 	al.sym = NULL;
-	thread__find_addr_location(thread, cpumode, MAP__FUNCTION,
+	if (cpumode == -1)
+		thread__find_cpumode_addr_location(thread, MAP__FUNCTION,
+						   ip, &al);
+	else
+		thread__find_addr_location(thread, cpumode, MAP__FUNCTION,
 				   ip, &al);
 	if (al.sym != NULL) {
 		if (sort__has_parent && !*parent &&
@@ -1427,8 +1432,50 @@ struct branch_info *sample__resolve_bstack(struct perf_sample *sample,
 	return bi;
 }
 
+#define CHASHSZ 127
+#define CHASHBITS 7
+#define NO_ENTRY 0xff
+
+#define PERF_MAX_BRANCH_DEPTH 127
+
+/* Remove loops. */
+static int remove_loops(struct branch_entry *l, int nr)
+{
+	int i, j, off;
+	unsigned char chash[CHASHSZ];
+
+	memset(chash, NO_ENTRY, sizeof(chash));
+
+	BUG_ON(PERF_MAX_BRANCH_DEPTH > 255);
+
+	for (i = 0; i < nr; i++) {
+		int h = hash_64(l[i].from, CHASHBITS) % CHASHSZ;
+
+		/* no collision handling for now */
+		if (chash[h] == NO_ENTRY) {
+			chash[h] = i;
+		} else if (l[chash[h]].from == l[i].from) {
+			bool is_loop = true;
+			/* check if it is a real loop */
+			off = 0;
+			for (j = chash[h]; j < i && i + off < nr; j++, off++)
+				if (l[j].from != l[i + off].from) {
+					is_loop = false;
+					break;
+				}
+			if (is_loop) {
+				memmove(l + i, l + i + off,
+					(nr - (i + off)) * sizeof(*l));
+				nr -= off;
+			}
+		}
+	}
+	return nr;
+}
+
 static int thread__resolve_callchain_sample(struct thread *thread,
 					     struct ip_callchain *chain,
+					     struct branch_stack *branch,
 					     struct symbol **parent,
 					     struct addr_location *root_al,
 					     int max_stack)
@@ -1438,22 +1485,82 @@ static int thread__resolve_callchain_sample(struct thread *thread,
 	int i;
 	int j;
 	int err;
-	int skip_idx __maybe_unused;
+	int skip_idx = -1;
+	int first_call = 0;
+
+	/*
+	 * Based on DWARF debug information, some architectures skip
+	 * a callchain entry saved by the kernel.
+	 */
+	if (chain->nr < PERF_MAX_STACK_DEPTH)
+		skip_idx = arch_skip_callchain_idx(thread, chain);
 
 	callchain_cursor_reset(&callchain_cursor);
 
+	/*
+	 * Add branches to call stack for easier browsing. This gives
+	 * more context for a sample than just the callers.
+	 *
+	 * This uses individual histograms of paths compared to the
+	 * aggregated histograms the normal LBR mode uses.
+	 *
+	 * Limitations for now:
+	 * - No extra filters
+	 * - No annotations (should annotate somehow)
+	 */
+
+	if (branch && callchain_param.branch_callstack) {
+		int nr = min(max_stack, (int)branch->nr);
+		struct branch_entry be[nr];
+
+		if (branch->nr > PERF_MAX_BRANCH_DEPTH) {
+			pr_warning("corrupted branch chain. skipping...\n");
+			goto check_calls;
+		}
+
+		for (i = 0; i < nr; i++) {
+			if (callchain_param.order == ORDER_CALLEE) {
+				be[i] = branch->entries[i];
+				/*
+				 * Check for overlap into the callchain.
+				 * The return address is one off compared to
+				 * the branch entry. To adjust for this
+				 * assume the calling instruction is not longer
+				 * than 8 bytes.
+				 */
+				if (i == skip_idx ||
+				    chain->ips[first_call] >= PERF_CONTEXT_MAX)
+					first_call++;
+				else if (be[i].from < chain->ips[first_call] &&
+				    be[i].from >= chain->ips[first_call] - 8)
+					first_call++;
+			} else
+				be[i] = branch->entries[branch->nr - i - 1];
+		}
+
+		nr = remove_loops(be, nr);
+
+		for (i = 0; i < nr; i++) {
+			err = add_callchain_ip(thread, parent, root_al,
+					       -1, be[i].to);
+			if (!err)
+				err = add_callchain_ip(thread, parent, root_al,
+						       -1, be[i].from);
+			if (err == -EINVAL)
+				break;
+			if (err)
+				return err;
+		}
+		chain_nr -= nr;
+	}
+
+check_calls:
 	if (chain->nr > PERF_MAX_STACK_DEPTH) {
 		pr_warning("corrupted callchain. skipping...\n");
 		return 0;
 	}
 
-	/*
-	 * Based on DWARF debug information, some architectures skip
-	 * a callchain entry saved by the kernel.
-	 */
-	skip_idx = arch_skip_callchain_idx(thread, chain);
-
-	for (i = 0; i < chain_nr; i++) {
+	for (i = first_call; i < chain_nr; i++) {
 		u64 ip;
 
 		if (callchain_param.order == ORDER_CALLEE)
@@ -1517,6 +1624,7 @@ int thread__resolve_callchain(struct thread *thread,
 			      int max_stack)
 {
 	int ret = thread__resolve_callchain_sample(thread, sample->callchain,
+						   sample->branch_stack,
 						   parent, root_al, max_stack);
 	if (ret)
 		return ret;