[PATCH v2 4/4] kasan: use stack_trace_save_shadow

[andrey.konovalov@linux.dev]

From: Andrey Konovalov <andreyknvl@google.com>

Now that stack_trace_save_shadow() is implemented by arm64, use it
whenever CONFIG_HAVE_SHADOW_STACKTRACE is enabled. This improves the
boot time of a defconfig build by ~30% for all KASAN modes.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 mm/kasan/common.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index d9079ec11f31..8d9d35c6562b 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -33,10 +33,13 @@
 depot_stack_handle_t kasan_save_stack(gfp_t flags, bool can_alloc)
 {
 	unsigned long entries[KASAN_STACK_DEPTH];
-	unsigned int nr_entries;
+	unsigned int size;
 
-	nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
-	return __stack_depot_save(entries, nr_entries, flags, can_alloc);
+	if (IS_ENABLED(CONFIG_HAVE_SHADOW_STACKTRACE))
+		size = stack_trace_save_shadow(entries, ARRAY_SIZE(entries), 0);
+	else
+		size = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
+	return __stack_depot_save(entries, size, flags, can_alloc);
 }
 
 void kasan_set_track(struct kasan_track *track, gfp_t flags)
-- 
2.25.1