kasan: remove redundant config option

CONFIG_KASAN_STACK and CONFIG_KASAN_STACK_ENABLE both enable KASAN stack
instrumentation, but we should only need one config, so that we remove
CONFIG_KASAN_STACK_ENABLE and make CONFIG_KASAN_STACK workable.  see [1].

When enable KASAN stack instrumentation, then for gcc we could do no
prompt and default value y, and for clang prompt and default value n.

This patch fixes the following compilation warning:

  include/linux/kasan.h:333:30: warning: 'CONFIG_KASAN_STACK' is not defined, evaluates to 0 [-Wundef]

[akpm@linux-foundation.org: fix merge snafu]

Link: https://bugzilla.kernel.org/show_bug.cgi?id=210221
Link: https://lkml.kernel.org/r/20210226012531.29231-1-walter-zh.wu@mediatek.com
Fixes: d9b571c885a8 ("kasan: fix KASAN_STACK dependency for HW_TAGS")
Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com>
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S
index 5bfd9b8..4ea9392 100644 (file)
--- a/arch/arm64/kernel/sleep.S
+++ b/arch/arm64/kernel/sleep.S
@@ -134,7 +134,7 @@ SYM_FUNC_START(_cpu_resume)
         */
        bl      cpu_do_resume
 
-#if defined(CONFIG_KASAN) && CONFIG_KASAN_STACK
+#if defined(CONFIG_KASAN) && defined(CONFIG_KASAN_STACK)
        mov     x0, sp
        bl      kasan_unpoison_task_stack_below
 #endif

diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S
index 56b6865..d5d8a35 100644 (file)
--- a/arch/x86/kernel/acpi/wakeup_64.S
+++ b/arch/x86/kernel/acpi/wakeup_64.S
@@ -115,7 +115,7 @@ SYM_FUNC_START(do_suspend_lowlevel)
        movq    pt_regs_r14(%rax), %r14
        movq    pt_regs_r15(%rax), %r15
 
-#if defined(CONFIG_KASAN) && CONFIG_KASAN_STACK
+#if defined(CONFIG_KASAN) && defined(CONFIG_KASAN_STACK)
        /*
         * The suspend path may have poisoned some areas deeper in the stack,
         * which we now need to unpoison.

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index b91732b..14f72ec 100644 (file)
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -330,7 +330,7 @@ static inline bool kasan_check_byte(const void *address)
 
 #endif /* CONFIG_KASAN */
 
-#if defined(CONFIG_KASAN) && CONFIG_KASAN_STACK
+#if defined(CONFIG_KASAN) && defined(CONFIG_KASAN_STACK)
 void kasan_unpoison_task_stack(struct task_struct *task);
 #else
 static inline void kasan_unpoison_task_stack(struct task_struct *task) {}

diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index fba9909..cffc2eb 100644 (file)
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan
@@ -138,9 +138,10 @@ config KASAN_INLINE
 
 endchoice
 
-config KASAN_STACK_ENABLE
+config KASAN_STACK
        bool "Enable stack instrumentation (unsafe)" if CC_IS_CLANG && !COMPILE_TEST
        depends on KASAN_GENERIC || KASAN_SW_TAGS
+       default y if CC_IS_GCC
        help
          The LLVM stack address sanitizer has a know problem that
          causes excessive stack usage in a lot of functions, see
@@ -154,12 +155,6 @@ config KASAN_STACK_ENABLE
          CONFIG_COMPILE_TEST.  On gcc it is assumed to always be safe
          to use and enabled by default.
 
-config KASAN_STACK
-       int
-       depends on KASAN_GENERIC || KASAN_SW_TAGS
-       default 1 if KASAN_STACK_ENABLE || CC_IS_GCC
-       default 0
-
 config KASAN_SW_TAGS_IDENTIFY
        bool "Enable memory corruption identification"
        depends on KASAN_SW_TAGS

diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index b5e08d4..7b53291 100644 (file)
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -63,7 +63,7 @@ void __kasan_unpoison_range(const void *address, size_t size)
        kasan_unpoison(address, size);
 }
 
-#if CONFIG_KASAN_STACK
+#ifdef CONFIG_KASAN_STACK
 /* Unpoison the entire stack for a task. */
 void kasan_unpoison_task_stack(struct task_struct *task)
 {

diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 8c55634..3436c6b 100644 (file)
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -231,7 +231,7 @@ void *kasan_find_first_bad_addr(void *addr, size_t size);
 const char *kasan_get_bug_type(struct kasan_access_info *info);
 void kasan_metadata_fetch_row(char *buffer, void *row);
 
-#if defined(CONFIG_KASAN_GENERIC) && CONFIG_KASAN_STACK
+#if defined(CONFIG_KASAN_GENERIC) && defined(CONFIG_KASAN_STACK)
 void kasan_print_address_stack_frame(const void *addr);
 #else
 static inline void kasan_print_address_stack_frame(const void *addr) { }

diff --git a/mm/kasan/report_generic.c b/mm/kasan/report_generic.c
index 41f3745..de732bc 100644 (file)
--- a/mm/kasan/report_generic.c
+++ b/mm/kasan/report_generic.c
@@ -128,7 +128,7 @@ void kasan_metadata_fetch_row(char *buffer, void *row)
        memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW);
 }
 
-#if CONFIG_KASAN_STACK
+#ifdef CONFIG_KASAN_STACK
 static bool __must_check tokenize_frame_descr(const char **frame_descr,
                                              char *token, size_t max_tok_len,
                                              unsigned long *value)

diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
index 127012f..3d79190 100644 (file)
--- a/scripts/Makefile.kasan
+++ b/scripts/Makefile.kasan
@@ -4,6 +4,12 @@ KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET)
 
 cc-param = $(call cc-option, -mllvm -$(1), $(call cc-option, --param $(1)))
 
+ifdef CONFIG_KASAN_STACK
+       stack_enable := 1
+else
+       stack_enable := 0
+endif
+
 ifdef CONFIG_KASAN_GENERIC
 
 ifdef CONFIG_KASAN_INLINE
@@ -27,7 +33,7 @@ else
        CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW) \
         $(call cc-param,asan-globals=1) \
         $(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
-        $(call cc-param,asan-stack=$(CONFIG_KASAN_STACK)) \
+        $(call cc-param,asan-stack=$(stack_enable)) \
         $(call cc-param,asan-instrument-allocas=1)
 endif
 
@@ -42,7 +48,7 @@ else
 endif
 
 CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
-               $(call cc-param,hwasan-instrument-stack=$(CONFIG_KASAN_STACK)) \
+               $(call cc-param,hwasan-instrument-stack=$(stack_enable)) \
                $(call cc-param,hwasan-use-short-granules=0) \
                $(instrumentation_flags)
 

diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening
index 269967c..a56c364 100644 (file)
--- a/security/Kconfig.hardening
+++ b/security/Kconfig.hardening
@@ -64,7 +64,7 @@ choice
        config GCC_PLUGIN_STRUCTLEAK_BYREF
                bool "zero-init structs passed by reference (strong)"
                depends on GCC_PLUGINS
-               depends on !(KASAN && KASAN_STACK=1)
+               depends on !(KASAN && KASAN_STACK)
                select GCC_PLUGIN_STRUCTLEAK
                help
                  Zero-initialize any structures on the stack that may
@@ -82,7 +82,7 @@ choice
        config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
                bool "zero-init anything passed by reference (very strong)"
                depends on GCC_PLUGINS
-               depends on !(KASAN && KASAN_STACK=1)
+               depends on !(KASAN && KASAN_STACK)
                select GCC_PLUGIN_STRUCTLEAK
                help
                  Zero-initialize any stack variables that may be passed