scripts/Makefile.kasan

   1 # SPDX-License-Identifier: GPL-2.0
   2
   3 ifdef CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX
   4 # Safe for compiler to generate meminstrinsic calls in uninstrumented files.
   5 CFLAGS_KASAN_NOSANITIZE :=
   6 else
   7 # Don't let compiler generate memintrinsic calls in uninstrumented files
   8 # because they are instrumented.
   9 CFLAGS_KASAN_NOSANITIZE := -fno-builtin
  10 endif
  11
  12 KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET)
  13
  14 cc-param = $(call cc-option, -mllvm -$(1), $(call cc-option, --param $(1)))
  15
  16 ifdef CONFIG_KASAN_STACK
  17         stack_enable := 1
  18 else
  19         stack_enable := 0
  20 endif
  21
  22 ifdef CONFIG_KASAN_GENERIC
  23
  24 ifdef CONFIG_KASAN_INLINE
  25         # When the number of memory accesses in a function is less than this
  26         # call threshold number, the compiler will use inline instrumentation.
  27         # 10000 is chosen offhand as a sufficiently large number to make all
  28         # kernel functions to be instrumented inline.
  29         call_threshold := 10000
  30 else
  31         call_threshold := 0
  32 endif
  33
  34 # First, enable -fsanitize=kernel-address together with providing the shadow
  35 # mapping offset, as for GCC, -fasan-shadow-offset fails without -fsanitize
  36 # (GCC accepts the shadow mapping offset via -fasan-shadow-offset instead of
  37 # a --param like the other KASAN parameters).
  38 # Instead of ifdef-checking the compiler, rely on cc-option.
  39 CFLAGS_KASAN := $(call cc-option, -fsanitize=kernel-address \
  40                 -fasan-shadow-offset=$(KASAN_SHADOW_OFFSET), \
  41                 $(call cc-option, -fsanitize=kernel-address \
  42                 -mllvm -asan-mapping-offset=$(KASAN_SHADOW_OFFSET)))
  43
  44 # Now, add other parameters enabled similarly in both GCC and Clang.
  45 # As some of them are not supported by older compilers, use cc-param.
  46 CFLAGS_KASAN += $(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
  47                 $(call cc-param,asan-stack=$(stack_enable)) \
  48                 $(call cc-param,asan-instrument-allocas=1) \
  49                 $(call cc-param,asan-globals=1)
  50
  51 # Instrument memcpy/memset/memmove calls by using instrumented __asan_mem*()
  52 # instead. With compilers that don't support this option, compiler-inserted
  53 # memintrinsics won't be checked by KASAN on GENERIC_ENTRY architectures.
  54 CFLAGS_KASAN += $(call cc-param,asan-kernel-mem-intrinsic-prefix=1)
  55
  56 endif # CONFIG_KASAN_GENERIC
  57
  58 ifdef CONFIG_KASAN_SW_TAGS
  59
  60 ifdef CONFIG_KASAN_INLINE
  61         instrumentation_flags := $(call cc-param,hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET))
  62 else
  63         instrumentation_flags := $(call cc-param,hwasan-instrument-with-calls=1)
  64 endif
  65
  66 CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
  67                 $(call cc-param,hwasan-instrument-stack=$(stack_enable)) \
  68                 $(call cc-param,hwasan-use-short-granules=0) \
  69                 $(call cc-param,hwasan-inline-all-checks=0) \
  70                 $(instrumentation_flags)
  71
  72 # Instrument memcpy/memset/memmove calls by using instrumented __hwasan_mem*().
  73 ifeq ($(call clang-min-version, 150000)$(call gcc-min-version, 130000),y)
  74         CFLAGS_KASAN += $(call cc-param,hwasan-kernel-mem-intrinsic-prefix=1)
  75 endif
  76
  77 endif # CONFIG_KASAN_SW_TAGS
  78
  79 export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE