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authorAndrey Konovalov <andreyknvl@gmail.com>2024-08-14 00:40:27 +0200
committerAndrew Morton <akpm@linux-foundation.org>2024-09-04 06:15:35 +0200
commit78788c3ede90727ffb7b17287468a08b4e78ee3d (patch)
tree94b1d3f806d7fd708536ee773fb0299eb609ec7f /scripts/Makefile.kasan
parentmm: shmem: support large folio swap out (diff)
downloadlinux-78788c3ede90727ffb7b17287468a08b4e78ee3d.tar.xz
linux-78788c3ede90727ffb7b17287468a08b4e78ee3d.zip
kasan: simplify and clarify Makefile
When KASAN support was being added to the Linux kernel, GCC did not yet support all of the KASAN-related compiler options. Thus, the KASAN Makefile had to probe the compiler for supported options. Nowadays, the Linux kernel GCC version requirement is 5.1+, and thus we don't need the probing of the -fasan-shadow-offset parameter: it exists in all 5.1+ GCCs. Simplify the KASAN Makefile to drop CFLAGS_KASAN_MINIMAL. Also add a few more comments and unify the indentation. [andreyknvl@gmail.com: comments fixes per Miguel] Link: https://lkml.kernel.org/r/20240814161052.10374-1-andrey.konovalov@linux.dev Link: https://lkml.kernel.org/r/20240813224027.84503-1-andrey.konovalov@linux.dev Signed-off-by: Andrey Konovalov <andreyknvl@gmail.com> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Acked-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Matthew Maurer <mmaurer@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to '')
-rw-r--r--scripts/Makefile.kasan45
1 files changed, 23 insertions, 22 deletions
diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
index 390658a2d5b7..aab4154af00a 100644
--- a/scripts/Makefile.kasan
+++ b/scripts/Makefile.kasan
@@ -22,30 +22,31 @@ endif
ifdef CONFIG_KASAN_GENERIC
ifdef CONFIG_KASAN_INLINE
+ # When the number of memory accesses in a function is less than this
+ # call threshold number, the compiler will use inline instrumentation.
+ # 10000 is chosen offhand as a sufficiently large number to make all
+ # kernel functions to be instrumented inline.
call_threshold := 10000
else
call_threshold := 0
endif
-CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-address
-
-# -fasan-shadow-offset fails without -fsanitize
-CFLAGS_KASAN_SHADOW := $(call cc-option, -fsanitize=kernel-address \
- -fasan-shadow-offset=$(KASAN_SHADOW_OFFSET), \
- $(call cc-option, -fsanitize=kernel-address \
- -mllvm -asan-mapping-offset=$(KASAN_SHADOW_OFFSET)))
-
-ifeq ($(strip $(CFLAGS_KASAN_SHADOW)),)
- CFLAGS_KASAN := $(CFLAGS_KASAN_MINIMAL)
-else
- # Now add all the compiler specific options that are valid standalone
- 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-instrument-allocas=1)
-endif
-
-CFLAGS_KASAN += $(call cc-param,asan-stack=$(stack_enable))
+# First, enable -fsanitize=kernel-address together with providing the shadow
+# mapping offset, as for GCC, -fasan-shadow-offset fails without -fsanitize
+# (GCC accepts the shadow mapping offset via -fasan-shadow-offset instead of
+# a --param like the other KASAN parameters).
+# Instead of ifdef-checking the compiler, rely on cc-option.
+CFLAGS_KASAN := $(call cc-option, -fsanitize=kernel-address \
+ -fasan-shadow-offset=$(KASAN_SHADOW_OFFSET), \
+ $(call cc-option, -fsanitize=kernel-address \
+ -mllvm -asan-mapping-offset=$(KASAN_SHADOW_OFFSET)))
+
+# Now, add other parameters enabled similarly in both GCC and Clang.
+# As some of them are not supported by older compilers, use cc-param.
+CFLAGS_KASAN += $(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
+ $(call cc-param,asan-stack=$(stack_enable)) \
+ $(call cc-param,asan-instrument-allocas=1) \
+ $(call cc-param,asan-globals=1)
# Instrument memcpy/memset/memmove calls by using instrumented __asan_mem*()
# instead. With compilers that don't support this option, compiler-inserted
@@ -57,9 +58,9 @@ endif # CONFIG_KASAN_GENERIC
ifdef CONFIG_KASAN_SW_TAGS
ifdef CONFIG_KASAN_INLINE
- instrumentation_flags := $(call cc-param,hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET))
+ instrumentation_flags := $(call cc-param,hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET))
else
- instrumentation_flags := $(call cc-param,hwasan-instrument-with-calls=1)
+ instrumentation_flags := $(call cc-param,hwasan-instrument-with-calls=1)
endif
CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
@@ -70,7 +71,7 @@ CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
# Instrument memcpy/memset/memmove calls by using instrumented __hwasan_mem*().
ifeq ($(call clang-min-version, 150000)$(call gcc-min-version, 130000),y)
-CFLAGS_KASAN += $(call cc-param,hwasan-kernel-mem-intrinsic-prefix=1)
+ CFLAGS_KASAN += $(call cc-param,hwasan-kernel-mem-intrinsic-prefix=1)
endif
endif # CONFIG_KASAN_SW_TAGS