Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Fri, 14 Aug 2020 19:26:45 +0200
In-Reply-To: <cover.1597425745.git.andreyknvl@google.com>
Message-Id: <272b331db9919432cd6467a0bd5ce73ffc46fc97.1597425745.git.andreyknvl@google.com>
Mime-Version: 1.0
References: <cover.1597425745.git.andreyknvl@google.com>
Subject: [PATCH 03/35] kasan: shadow declarations only for software modes
From:   Andrey Konovalov <andreyknvl@google.com>
To:     Dmitry Vyukov <dvyukov@google.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        kasan-dev@googlegroups.com
Cc:     Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Marco Elver <elver@google.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Elena Petrova <lenaptr@google.com>,
        Branislav Rankov <Branislav.Rankov@arm.com>,
        Kevin Brodsky <kevin.brodsky@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        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"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.

Group shadow-related KASAN function declarations and only define them
for the two existing software modes.

No functional changes for software modes.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 include/linux/kasan.h | 44 ++++++++++++++++++++++++++-----------------
 1 file changed, 27 insertions(+), 17 deletions(-)

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index bd5b4965a269..44a9aae44138 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -3,16 +3,24 @@
 #define _LINUX_KASAN_H
 
 #include <linux/types.h>
+#include <asm/kasan.h>
 
 struct kmem_cache;
 struct page;
 struct vm_struct;
 struct task_struct;
 
-#ifdef CONFIG_KASAN
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
 
 #include <linux/pgtable.h>
-#include <asm/kasan.h>
+
+/* Software KASAN implementations use shadow memory. */
+
+#ifdef CONFIG_KASAN_SW_TAGS
+#define KASAN_SHADOW_INIT 0xFF
+#else
+#define KASAN_SHADOW_INIT 0
+#endif
 
 extern unsigned char kasan_early_shadow_page[PAGE_SIZE];
 extern pte_t kasan_early_shadow_pte[PTRS_PER_PTE];
@@ -29,6 +37,23 @@ static inline void *kasan_mem_to_shadow(const void *addr)
 		+ KASAN_SHADOW_OFFSET;
 }
 
+int kasan_add_zero_shadow(void *start, unsigned long size);
+void kasan_remove_zero_shadow(void *start, unsigned long size);
+
+#else /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
+
+static inline int kasan_add_zero_shadow(void *start, unsigned long size)
+{
+	return 0;
+}
+static inline void kasan_remove_zero_shadow(void *start,
+					unsigned long size)
+{}
+
+#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
+
+#ifdef CONFIG_KASAN
+
 /* Enable reporting bugs after kasan_disable_current() */
 extern void kasan_enable_current(void);
 
@@ -69,9 +94,6 @@ struct kasan_cache {
 	int free_meta_offset;
 };
 
-int kasan_add_zero_shadow(void *start, unsigned long size);
-void kasan_remove_zero_shadow(void *start, unsigned long size);
-
 size_t __ksize(const void *);
 static inline void kasan_unpoison_slab(const void *ptr)
 {
@@ -137,14 +159,6 @@ static inline bool kasan_slab_free(struct kmem_cache *s, void *object,
 	return false;
 }
 
-static inline int kasan_add_zero_shadow(void *start, unsigned long size)
-{
-	return 0;
-}
-static inline void kasan_remove_zero_shadow(void *start,
-					unsigned long size)
-{}
-
 static inline void kasan_unpoison_slab(const void *ptr) { }
 static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
 
@@ -152,8 +166,6 @@ static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
 
 #ifdef CONFIG_KASAN_GENERIC
 
-#define KASAN_SHADOW_INIT 0
-
 void kasan_cache_shrink(struct kmem_cache *cache);
 void kasan_cache_shutdown(struct kmem_cache *cache);
 void kasan_record_aux_stack(void *ptr);
@@ -168,8 +180,6 @@ static inline void kasan_record_aux_stack(void *ptr) {}
 
 #ifdef CONFIG_KASAN_SW_TAGS
 
-#define KASAN_SHADOW_INIT 0xFF
-
 void kasan_init_tags(void);
 
 void *kasan_reset_tag(const void *addr);
-- 
2.28.0.220.ged08abb693-goog