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23066c3f4e
Commit 217c3e0196 ("disable stringop truncation warnings for now")
disabled -Wstringop-truncation since it was too noisy.
Having __nonstring available allows us to let GCC know that a string
is not meant to be NUL-terminated, which helps suppressing some
-Wstringop-truncation warnings.
Note that using __nonstring actually triggers other warnings
(-Wstringop-overflow, which is on by default) which may be real
problems. Therefore, cleaning up -Wstringop-truncation warnings
also buys us the ability to uncover further potential problems.
To encourage the use of __nonstring, we put the warning back at W=1.
In the future, if we end up with a fairly warning-free tree,
we might want to enable it by default.
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # on top of v4.19-rc5, clang 7
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
78 lines
2.8 KiB
Makefile
78 lines
2.8 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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# ==========================================================================
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#
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# make W=... settings
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#
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# W=1 - warnings that may be relevant and does not occur too often
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# W=2 - warnings that occur quite often but may still be relevant
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# W=3 - the more obscure warnings, can most likely be ignored
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#
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# $(call cc-option, -W...) handles gcc -W.. options which
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# are not supported by all versions of the compiler
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# ==========================================================================
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KBUILD_CFLAGS += $(call cc-disable-warning, packed-not-aligned)
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ifeq ("$(origin W)", "command line")
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export KBUILD_ENABLE_EXTRA_GCC_CHECKS := $(W)
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endif
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ifdef KBUILD_ENABLE_EXTRA_GCC_CHECKS
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warning- := $(empty)
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warning-1 := -Wextra -Wunused -Wno-unused-parameter
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warning-1 += -Wmissing-declarations
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warning-1 += -Wmissing-format-attribute
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warning-1 += $(call cc-option, -Wmissing-prototypes)
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warning-1 += -Wold-style-definition
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warning-1 += $(call cc-option, -Wmissing-include-dirs)
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warning-1 += $(call cc-option, -Wunused-but-set-variable)
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warning-1 += $(call cc-option, -Wunused-const-variable)
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warning-1 += $(call cc-option, -Wpacked-not-aligned)
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warning-1 += $(call cc-option, -Wstringop-truncation)
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warning-1 += $(call cc-disable-warning, missing-field-initializers)
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warning-1 += $(call cc-disable-warning, sign-compare)
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warning-2 := -Waggregate-return
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warning-2 += -Wcast-align
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warning-2 += -Wdisabled-optimization
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warning-2 += -Wnested-externs
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warning-2 += -Wshadow
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warning-2 += $(call cc-option, -Wlogical-op)
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warning-2 += $(call cc-option, -Wmissing-field-initializers)
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warning-2 += $(call cc-option, -Wsign-compare)
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warning-2 += $(call cc-option, -Wmaybe-uninitialized)
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warning-2 += $(call cc-option, -Wunused-macros)
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warning-3 := -Wbad-function-cast
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warning-3 += -Wcast-qual
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warning-3 += -Wconversion
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warning-3 += -Wpacked
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warning-3 += -Wpadded
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warning-3 += -Wpointer-arith
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warning-3 += -Wredundant-decls
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warning-3 += -Wswitch-default
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warning-3 += $(call cc-option, -Wpacked-bitfield-compat)
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warning-3 += $(call cc-option, -Wvla)
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warning := $(warning-$(findstring 1, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
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warning += $(warning-$(findstring 2, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
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warning += $(warning-$(findstring 3, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
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ifeq ("$(strip $(warning))","")
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$(error W=$(KBUILD_ENABLE_EXTRA_GCC_CHECKS) is unknown)
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endif
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KBUILD_CFLAGS += $(warning)
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else
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ifeq ($(cc-name),clang)
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KBUILD_CFLAGS += $(call cc-disable-warning, initializer-overrides)
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KBUILD_CFLAGS += $(call cc-disable-warning, unused-value)
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KBUILD_CFLAGS += $(call cc-disable-warning, format)
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KBUILD_CFLAGS += $(call cc-disable-warning, sign-compare)
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KBUILD_CFLAGS += $(call cc-disable-warning, format-zero-length)
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KBUILD_CFLAGS += $(call cc-disable-warning, uninitialized)
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endif
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endif
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