kasan, arm64: only use kasan_depth for software modes

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

Hardware tag-based KASAN won't use kasan_depth.  Only define and use it
when one of the software KASAN modes are enabled.

No functional changes for software modes.

Link: https://lkml.kernel.org/r/e16f15aeda90bc7fb4dfc2e243a14b74cc5c8219.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index ffeb80d5aa8d42a1932616d2c4ab95e7af6a4e16..5172799f831f90ab779f97bfd233671349dfeef8 100644 (file)
--- a/arch/arm64/mm/kasan_init.c
+++ b/arch/arm64/mm/kasan_init.c
@@ -273,17 +273,22 @@ static void __init kasan_init_shadow(void)
        cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
 }
 
+static void __init kasan_init_depth(void)
+{
+       init_task.kasan_depth = 0;
+}
+
 #else /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS) */
 
 static inline void __init kasan_init_shadow(void) { }
 
+static inline void __init kasan_init_depth(void) { }
+
 #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
 
 void __init kasan_init(void)
 {
        kasan_init_shadow();
-
-       /* At this point kasan is fully initialized. Enable error messages */
-       init_task.kasan_depth = 0;
+       kasan_init_depth();
        pr_info("KernelAddressSanitizer initialized\n");
 }

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 9740c06a04a14458f2e319ac23d28d7985a18531..b272960e8396b148ca5dd7d26a4c814623cabef0 100644 (file)
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -52,6 +52,12 @@ static inline void *kasan_mem_to_shadow(const void *addr)
 int kasan_add_zero_shadow(void *start, unsigned long size);
 void kasan_remove_zero_shadow(void *start, unsigned long size);
 
+/* Enable reporting bugs after kasan_disable_current() */
+extern void kasan_enable_current(void);
+
+/* Disable reporting bugs for current task */
+extern void kasan_disable_current(void);
+
 #else /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
 
 static inline int kasan_add_zero_shadow(void *start, unsigned long size)
@@ -62,16 +68,13 @@ static inline void kasan_remove_zero_shadow(void *start,
                                        unsigned long size)
 {}
 
+static inline void kasan_enable_current(void) {}
+static inline void kasan_disable_current(void) {}
+
 #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
 
 #ifdef CONFIG_KASAN
 
-/* Enable reporting bugs after kasan_disable_current() */
-extern void kasan_enable_current(void);
-
-/* Disable reporting bugs for current task */
-extern void kasan_disable_current(void);
-
 void kasan_unpoison_range(const void *address, size_t size);
 
 void kasan_unpoison_task_stack(struct task_struct *task);
@@ -122,9 +125,6 @@ static inline void kasan_unpoison_range(const void *address, size_t size) {}
 
 static inline void kasan_unpoison_task_stack(struct task_struct *task) {}
 
-static inline void kasan_enable_current(void) {}
-static inline void kasan_disable_current(void) {}
-
 static inline void kasan_alloc_pages(struct page *page, unsigned int order) {}
 static inline void kasan_free_pages(struct page *page, unsigned int order) {}
 

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 51d535b69bd6fce5253c09a7a6c01c9087c7f365..6e3a5eeec509a193b5f2f3d07348a68f188a6f18 100644 (file)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1234,7 +1234,7 @@ struct task_struct {
        u64                             timer_slack_ns;
        u64                             default_timer_slack_ns;
 
-#ifdef CONFIG_KASAN
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
        unsigned int                    kasan_depth;
 #endif
 

diff --git a/init/init_task.c b/init/init_task.c
index 15f6eb93a04fa2f01989c5f5316206e2d00da8d7..8a992d73e6fb7027e0b7b642b3935d81cb518fec 100644 (file)
--- a/init/init_task.c
+++ b/init/init_task.c
@@ -176,7 +176,7 @@ struct task_struct init_task
        .numa_group     = NULL,
        .numa_faults    = NULL,
 #endif
-#ifdef CONFIG_KASAN
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
        .kasan_depth    = 1,
 #endif
 #ifdef CONFIG_KCSAN

diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 663ffa71cd20a58f5c78e9c0e949b44809a17a2c..d5f23b2f170ab9b87461a4ea1daec707599a4f03 100644 (file)
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -46,6 +46,7 @@ void kasan_set_track(struct kasan_track *track, gfp_t flags)
        track->stack = kasan_save_stack(flags);
 }
 
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
 void kasan_enable_current(void)
 {
        current->kasan_depth++;
@@ -55,6 +56,7 @@ void kasan_disable_current(void)
 {
        current->kasan_depth--;
 }
+#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
 
 void kasan_unpoison_range(const void *address, size_t size)
 {

diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index d140d26cfb316a3fdbc9413773e123e0929a6d81..914ab5cfc3ea26b9c404571b5b90df2c3561f0b4 100644 (file)
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -292,8 +292,10 @@ static void print_shadow_for_address(const void *addr)
 
 static bool report_enabled(void)
 {
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
        if (current->kasan_depth)
                return false;
+#endif
        if (test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags))
                return true;
        return !test_and_set_bit(KASAN_BIT_REPORTED, &kasan_flags);