[PATCH V2 07/10] kasan: Make INLINE KASan support arch selectable

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

Some of the archs, may find it difficult to support inline KASan
mode. Add HAVE_ARCH_KASAN_INLINE so that we can disable inline
support at config time.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/x86/Kconfig       |  1 +
 lib/Kconfig.kasan      |  2 ++
 scripts/Makefile.kasan | 28 ++++++++++++++--------------
 3 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b3a1a5d77d92..4416f80580fb 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -78,6 +78,7 @@ config X86
 	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
 	select HAVE_ARCH_JUMP_LABEL
 	select HAVE_ARCH_KASAN			if X86_64 && SPARSEMEM_VMEMMAP
+	select HAVE_ARCH_KASAN_INLINE			if X86_64 && SPARSEMEM_VMEMMAP
 	select HAVE_ARCH_KGDB
 	select HAVE_ARCH_KMEMCHECK
 	select HAVE_ARCH_SECCOMP_FILTER
diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index 39f24d6721e5..e9d1bb1175b8 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan
@@ -32,6 +32,7 @@ config KASAN_OUTLINE
 	  however it doesn't bloat size of kernel's .text section so
 	  much as inline does.
 
+if HAVE_ARCH_KASAN_INLINE
 config KASAN_INLINE
 	bool "Inline instrumentation"
 	help
@@ -40,6 +41,7 @@ config KASAN_INLINE
 	  it gives about x2 boost over outline instrumentation), but
 	  make kernel's .text size much bigger.
 	  This requires a gcc version of 5.0 or later.
+endif
 
 endchoice
 
diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
index 3f874d24234f..c1c06e9e107a 100644
--- a/scripts/Makefile.kasan
+++ b/scripts/Makefile.kasan
@@ -1,29 +1,29 @@
 ifdef CONFIG_KASAN
-ifdef CONFIG_KASAN_INLINE
-	call_threshold := 10000
-else
-	call_threshold := 0
-endif
-
-CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-address
 
 CFLAGS_KASAN := $(call cc-option, -fsanitize=kernel-address \
-		-fasan-shadow-offset=$(CONFIG_KASAN_SHADOW_OFFSET) \
-		--param asan-stack=1 --param asan-globals=1 \
-		--param asan-instrumentation-with-call-threshold=$(call_threshold))
-
-ifeq ($(call cc-option, $(CFLAGS_KASAN_MINIMAL) -Werror),)
+                   --param asan-instrumentation-with-call-threshold=0)
+ifeq ($(CFLAGS_KASAN),)
    ifneq ($(CONFIG_COMPILE_TEST),y)
         $(warning Cannot use CONFIG_KASAN: \
             -fsanitize=kernel-address is not supported by compiler)
    endif
 else
-    ifeq ($(CFLAGS_KASAN),)
+
+   ifdef CONFIG_KASAN_INLINE
+   CFLAGS_KASAN_INLINE := $(call cc-option, -fsanitize=kernel-address \
+                        -fasan-shadow-offset=$(CONFIG_KASAN_SHADOW_OFFSET) \
+                        --param asan-stack=1 --param asan-globals=1 \
+                        --param asan-instrumentation-with-call-threshold=10000)
+
+    ifeq ($(CFLAGS_KASAN_INLINE),)
         ifneq ($(CONFIG_COMPILE_TEST),y)
             $(warning CONFIG_KASAN: compiler does not support all options.\
                 Trying minimal configuration)
         endif
-        CFLAGS_KASAN := $(CFLAGS_KASAN_MINIMAL)
+    else
+        CFLAGS_KASAN := $(CFLAGS_KASAN_INLINE)
     endif
+    endif
+
 endif
 endif
-- 
2.5.0