| Message ID | 20240814085618.968833-3-samuel.holland@sifive.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | kasan: RISC-V support for KASAN_SW_TAGS using pointer masking | expand |
On Wed, Aug 14, 2024 at 10:56 AM Samuel Holland <samuel.holland@sifive.com> wrote: > > On RISC-V, the ISA extension required to dereference tagged pointers is > optional, and the interface to enable pointer masking requires firmware > support. Therefore, we must detect at runtime if sw_tags is usable on a > given machine. Reuse the logic from hw_tags to dynamically enable KASAN. > > This commit makes no functional change to the KASAN_HW_TAGS code path. > > Signed-off-by: Samuel Holland <samuel.holland@sifive.com> > --- > > include/linux/kasan-enabled.h | 15 +++++---------- > mm/kasan/hw_tags.c | 10 ---------- > mm/kasan/tags.c | 10 ++++++++++ > 3 files changed, 15 insertions(+), 20 deletions(-) > > diff --git a/include/linux/kasan-enabled.h b/include/linux/kasan-enabled.h > index 6f612d69ea0c..648bda9495b7 100644 > --- a/include/linux/kasan-enabled.h > +++ b/include/linux/kasan-enabled.h > @@ -4,7 +4,7 @@ > > #include <linux/static_key.h> > > -#ifdef CONFIG_KASAN_HW_TAGS > +#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) > > DECLARE_STATIC_KEY_FALSE(kasan_flag_enabled); > > @@ -13,23 +13,18 @@ static __always_inline bool kasan_enabled(void) > return static_branch_likely(&kasan_flag_enabled); > } > > -static inline bool kasan_hw_tags_enabled(void) > -{ > - return kasan_enabled(); > -} > - > -#else /* CONFIG_KASAN_HW_TAGS */ > +#else /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */ > > static inline bool kasan_enabled(void) > { > return IS_ENABLED(CONFIG_KASAN); > } > > +#endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */ > + > static inline bool kasan_hw_tags_enabled(void) > { > - return false; > + return IS_ENABLED(CONFIG_KASAN_HW_TAGS) && kasan_enabled(); > } > > -#endif /* CONFIG_KASAN_HW_TAGS */ > - > #endif /* LINUX_KASAN_ENABLED_H */ > diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c > index 9958ebc15d38..c3beeb94efa5 100644 > --- a/mm/kasan/hw_tags.c > +++ b/mm/kasan/hw_tags.c > @@ -43,13 +43,6 @@ static enum kasan_arg kasan_arg __ro_after_init; > static enum kasan_arg_mode kasan_arg_mode __ro_after_init; > static enum kasan_arg_vmalloc kasan_arg_vmalloc __initdata; > > -/* > - * Whether KASAN is enabled at all. > - * The value remains false until KASAN is initialized by kasan_init_hw_tags(). > - */ > -DEFINE_STATIC_KEY_FALSE(kasan_flag_enabled); > -EXPORT_SYMBOL(kasan_flag_enabled); > - > /* > * Whether the selected mode is synchronous, asynchronous, or asymmetric. > * Defaults to KASAN_MODE_SYNC. > @@ -257,9 +250,6 @@ void __init kasan_init_hw_tags(void) > > kasan_init_tags(); > > - /* KASAN is now initialized, enable it. */ > - static_branch_enable(&kasan_flag_enabled); > - > pr_info("KernelAddressSanitizer initialized (hw-tags, mode=%s, vmalloc=%s, stacktrace=%s)\n", > kasan_mode_info(), > kasan_vmalloc_enabled() ? "on" : "off", > diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c > index d65d48b85f90..c111d98961ed 100644 > --- a/mm/kasan/tags.c > +++ b/mm/kasan/tags.c > @@ -32,6 +32,13 @@ enum kasan_arg_stacktrace { > > static enum kasan_arg_stacktrace kasan_arg_stacktrace __initdata; > > +/* > + * Whether KASAN is enabled at all. > + * The value remains false until KASAN is initialized by kasan_init_tags(). > + */ > +DEFINE_STATIC_KEY_FALSE(kasan_flag_enabled); > +EXPORT_SYMBOL(kasan_flag_enabled); > + > /* Whether to collect alloc/free stack traces. */ > DEFINE_STATIC_KEY_TRUE(kasan_flag_stacktrace); > > @@ -92,6 +99,9 @@ void __init kasan_init_tags(void) > if (WARN_ON(!stack_ring.entries)) > static_branch_disable(&kasan_flag_stacktrace); > } > + > + /* KASAN is now initialized, enable it. */ > + static_branch_enable(&kasan_flag_enabled); > } > > static void save_stack_info(struct kmem_cache *cache, void *object, > -- > 2.45.1 > Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
diff --git a/include/linux/kasan-enabled.h b/include/linux/kasan-enabled.h index 6f612d69ea0c..648bda9495b7 100644 --- a/include/linux/kasan-enabled.h +++ b/include/linux/kasan-enabled.h @@ -4,7 +4,7 @@ #include <linux/static_key.h> -#ifdef CONFIG_KASAN_HW_TAGS +#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) DECLARE_STATIC_KEY_FALSE(kasan_flag_enabled); @@ -13,23 +13,18 @@ static __always_inline bool kasan_enabled(void) return static_branch_likely(&kasan_flag_enabled); } -static inline bool kasan_hw_tags_enabled(void) -{ - return kasan_enabled(); -} - -#else /* CONFIG_KASAN_HW_TAGS */ +#else /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */ static inline bool kasan_enabled(void) { return IS_ENABLED(CONFIG_KASAN); } +#endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */ + static inline bool kasan_hw_tags_enabled(void) { - return false; + return IS_ENABLED(CONFIG_KASAN_HW_TAGS) && kasan_enabled(); } -#endif /* CONFIG_KASAN_HW_TAGS */ - #endif /* LINUX_KASAN_ENABLED_H */ diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c index 9958ebc15d38..c3beeb94efa5 100644 --- a/mm/kasan/hw_tags.c +++ b/mm/kasan/hw_tags.c @@ -43,13 +43,6 @@ static enum kasan_arg kasan_arg __ro_after_init; static enum kasan_arg_mode kasan_arg_mode __ro_after_init; static enum kasan_arg_vmalloc kasan_arg_vmalloc __initdata; -/* - * Whether KASAN is enabled at all. - * The value remains false until KASAN is initialized by kasan_init_hw_tags(). - */ -DEFINE_STATIC_KEY_FALSE(kasan_flag_enabled); -EXPORT_SYMBOL(kasan_flag_enabled); - /* * Whether the selected mode is synchronous, asynchronous, or asymmetric. * Defaults to KASAN_MODE_SYNC. @@ -257,9 +250,6 @@ void __init kasan_init_hw_tags(void) kasan_init_tags(); - /* KASAN is now initialized, enable it. */ - static_branch_enable(&kasan_flag_enabled); - pr_info("KernelAddressSanitizer initialized (hw-tags, mode=%s, vmalloc=%s, stacktrace=%s)\n", kasan_mode_info(), kasan_vmalloc_enabled() ? "on" : "off", diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c index d65d48b85f90..c111d98961ed 100644 --- a/mm/kasan/tags.c +++ b/mm/kasan/tags.c @@ -32,6 +32,13 @@ enum kasan_arg_stacktrace { static enum kasan_arg_stacktrace kasan_arg_stacktrace __initdata; +/* + * Whether KASAN is enabled at all. + * The value remains false until KASAN is initialized by kasan_init_tags(). + */ +DEFINE_STATIC_KEY_FALSE(kasan_flag_enabled); +EXPORT_SYMBOL(kasan_flag_enabled); + /* Whether to collect alloc/free stack traces. */ DEFINE_STATIC_KEY_TRUE(kasan_flag_stacktrace); @@ -92,6 +99,9 @@ void __init kasan_init_tags(void) if (WARN_ON(!stack_ring.entries)) static_branch_disable(&kasan_flag_stacktrace); } + + /* KASAN is now initialized, enable it. */ + static_branch_enable(&kasan_flag_enabled); } static void save_stack_info(struct kmem_cache *cache, void *object,
On RISC-V, the ISA extension required to dereference tagged pointers is optional, and the interface to enable pointer masking requires firmware support. Therefore, we must detect at runtime if sw_tags is usable on a given machine. Reuse the logic from hw_tags to dynamically enable KASAN. This commit makes no functional change to the KASAN_HW_TAGS code path. Signed-off-by: Samuel Holland <samuel.holland@sifive.com> --- include/linux/kasan-enabled.h | 15 +++++---------- mm/kasan/hw_tags.c | 10 ---------- mm/kasan/tags.c | 10 ++++++++++ 3 files changed, 15 insertions(+), 20 deletions(-)