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Date:   Tue, 10 Nov 2020 23:20:12 +0100
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Subject: [PATCH v2 08/20] kasan: inline random_tag for HW_TAGS
From:   Andrey Konovalov <andreyknvl@google.com>
To:     Dmitry Vyukov <dvyukov@google.com>,
        Alexander Potapenko <glider@google.com>,
        Marco Elver <elver@google.com>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Branislav Rankov <Branislav.Rankov@arm.com>,
        Kevin Brodsky <kevin.brodsky@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Andrey Konovalov <andreyknvl@google.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Using random_tag() currently results in a function call. Move its
definition to mm/kasan/kasan.h and turn it into a static inline function
for hardware tag-based mode to avoid uneeded function calls.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Link: https://linux-review.googlesource.com/id/Iac5b2faf9a912900e16cca6834d621f5d4abf427
---
 mm/kasan/hw_tags.c |  5 -----
 mm/kasan/kasan.h   | 34 +++++++++++++++++-----------------
 2 files changed, 17 insertions(+), 22 deletions(-)

diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
index 49ea5f5c5643..1476ac07666e 100644
--- a/mm/kasan/hw_tags.c
+++ b/mm/kasan/hw_tags.c
@@ -42,11 +42,6 @@ void kasan_unpoison_memory(const void *address, size_t size)
 			round_up(size, KASAN_GRANULE_SIZE), get_tag(address));
 }
 
-u8 random_tag(void)
-{
-	return hw_get_random_tag();
-}
-
 bool check_invalid_free(void *addr)
 {
 	u8 ptr_tag = get_tag(addr);
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 8a5501ef2339..7498839a15d3 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -188,6 +188,12 @@ static inline bool addr_has_metadata(const void *addr)
 
 #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
 
+#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
+void print_tags(u8 addr_tag, const void *addr);
+#else
+static inline void print_tags(u8 addr_tag, const void *addr) { }
+#endif
+
 bool check_invalid_free(void *addr);
 
 void *find_first_bad_addr(void *addr, size_t size);
@@ -223,23 +229,6 @@ static inline void quarantine_reduce(void) { }
 static inline void quarantine_remove_cache(struct kmem_cache *cache) { }
 #endif
 
-#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
-
-void print_tags(u8 addr_tag, const void *addr);
-
-u8 random_tag(void);
-
-#else
-
-static inline void print_tags(u8 addr_tag, const void *addr) { }
-
-static inline u8 random_tag(void)
-{
-	return 0;
-}
-
-#endif
-
 #ifndef arch_kasan_set_tag
 static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
 {
@@ -279,6 +268,17 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
 
 #endif /* CONFIG_KASAN_HW_TAGS */
 
+#ifdef CONFIG_KASAN_SW_TAGS
+u8 random_tag(void);
+#elif defined(CONFIG_KASAN_HW_TAGS)
+#define random_tag() hw_get_random_tag()
+#else
+static inline u8 random_tag(void)
+{
+	return 0;
+}
+#endif
+
 /*
  * Exported functions for interfaces called from assembly or from generated
  * code. Declarations here to avoid warning about missing declarations.
-- 
2.29.2.222.g5d2a92d10f8-goog