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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>
80 lines
2.9 KiB
Makefile
80 lines
2.9 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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ifdef CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX
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# Safe for compiler to generate meminstrinsic calls in uninstrumented files.
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CFLAGS_KASAN_NOSANITIZE :=
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else
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# Don't let compiler generate memintrinsic calls in uninstrumented files
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# because they are instrumented.
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CFLAGS_KASAN_NOSANITIZE := -fno-builtin
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endif
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KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET)
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cc-param = $(call cc-option, -mllvm -$(1), $(call cc-option, --param $(1)))
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ifdef CONFIG_KASAN_STACK
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stack_enable := 1
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else
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stack_enable := 0
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endif
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ifdef CONFIG_KASAN_GENERIC
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ifdef CONFIG_KASAN_INLINE
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# When the number of memory accesses in a function is less than this
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# call threshold number, the compiler will use inline instrumentation.
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# 10000 is chosen offhand as a sufficiently large number to make all
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# kernel functions to be instrumented inline.
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call_threshold := 10000
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else
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call_threshold := 0
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endif
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# First, enable -fsanitize=kernel-address together with providing the shadow
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# mapping offset, as for GCC, -fasan-shadow-offset fails without -fsanitize
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# (GCC accepts the shadow mapping offset via -fasan-shadow-offset instead of
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# a --param like the other KASAN parameters).
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# Instead of ifdef-checking the compiler, rely on cc-option.
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CFLAGS_KASAN := $(call cc-option, -fsanitize=kernel-address \
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-fasan-shadow-offset=$(KASAN_SHADOW_OFFSET), \
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$(call cc-option, -fsanitize=kernel-address \
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-mllvm -asan-mapping-offset=$(KASAN_SHADOW_OFFSET)))
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# Now, add other parameters enabled similarly in both GCC and Clang.
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# As some of them are not supported by older compilers, use cc-param.
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CFLAGS_KASAN += $(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
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$(call cc-param,asan-stack=$(stack_enable)) \
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$(call cc-param,asan-instrument-allocas=1) \
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$(call cc-param,asan-globals=1)
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# Instrument memcpy/memset/memmove calls by using instrumented __asan_mem*()
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# instead. With compilers that don't support this option, compiler-inserted
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# memintrinsics won't be checked by KASAN on GENERIC_ENTRY architectures.
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CFLAGS_KASAN += $(call cc-param,asan-kernel-mem-intrinsic-prefix=1)
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endif # CONFIG_KASAN_GENERIC
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ifdef CONFIG_KASAN_SW_TAGS
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ifdef CONFIG_KASAN_INLINE
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instrumentation_flags := $(call cc-param,hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET))
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else
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instrumentation_flags := $(call cc-param,hwasan-instrument-with-calls=1)
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endif
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CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
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$(call cc-param,hwasan-instrument-stack=$(stack_enable)) \
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$(call cc-param,hwasan-use-short-granules=0) \
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$(call cc-param,hwasan-inline-all-checks=0) \
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$(instrumentation_flags)
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# Instrument memcpy/memset/memmove calls by using instrumented __hwasan_mem*().
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ifeq ($(call clang-min-version, 150000)$(call gcc-min-version, 130000),y)
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CFLAGS_KASAN += $(call cc-param,hwasan-kernel-mem-intrinsic-prefix=1)
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endif
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endif # CONFIG_KASAN_SW_TAGS
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export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE
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