In commit 8b202ee21839 ("s390: disable -Warray-bounds") the s390 people disabled the '-Warray-bounds' warning for gcc-12, because the new logic in gcc would cause warnings for their use of the S390_lowcore macro, which accesses absolute pointers. It turns out gcc-12 has many other issues in this area, so this takes that s390 warning disable logic, and turns it into a kernel build config entry instead. Part of the intent is that we can make this all much more targeted, and use this conflig flag to disable it in only particular configurations that cause problems, with the s390 case as an example: select GCC12_NO_ARRAY_BOUNDS and we could do that for other configuration cases that cause issues. Or we could possibly use the CONFIG_CC_NO_ARRAY_BOUNDS thing in a more targeted way, and disable the warning only for particular uses: again the s390 case as an example: KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_CC_NO_ARRAY_BOUNDS),-Wno-array-bounds) but this ends up just doing it globally in the top-level Makefile, since the current issues are spread fairly widely all over: KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds We'll try to limit this later, since the gcc-12 problems are rare enough that *much* of the kernel can be built with it without disabling this warning.
Unified · Split
| @@ -788,6 +788,7 @@ stackp-flags-$(CONFIG_STACKPROTECTOR_STRONG) := -fstack-protector-strong · 787 unmodified lines | |||
| 788 | KBUILD_CFLAGS += $(stackp-flags-y) | 788 | KBUILD_CFLAGS += $(stackp-flags-y) |
| 789 | 789 | ||
| 790 | KBUILD_CFLAGS-$(CONFIG_WERROR) += -Werror | 790 | KBUILD_CFLAGS-$(CONFIG_WERROR) += -Werror |
| 791 | KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds | ||
| 791 | KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_CC_IMPLICIT_FALLTHROUGH) | 792 | KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_CC_IMPLICIT_FALLTHROUGH) |
| 792 | 793 | ||
| 793 | ifdef CONFIG_CC_IS_CLANG | 794 | ifdef CONFIG_CC_IS_CLANG |
| @@ -125,6 +125,7 @@ config S390 · 124 unmodified lines | |||
| 125 | select CLONE_BACKWARDS2 | 125 | select CLONE_BACKWARDS2 |
| 126 | select DMA_OPS if PCI | 126 | select DMA_OPS if PCI |
| 127 | select DYNAMIC_FTRACE if FUNCTION_TRACER | 127 | select DYNAMIC_FTRACE if FUNCTION_TRACER |
| 128 | select GCC12_NO_ARRAY_BOUNDS | ||
| 128 | select GENERIC_ALLOCATOR | 129 | select GENERIC_ALLOCATOR |
| 129 | select GENERIC_CPU_AUTOPROBE | 130 | select GENERIC_CPU_AUTOPROBE |
| 130 | select GENERIC_CPU_VULNERABILITIES | 131 | select GENERIC_CPU_VULNERABILITIES |
| @@ -32,15 +32,7 @@ KBUILD_CFLAGS_DECOMPRESSOR += -fno-stack-protector · 31 unmodified lines | |||
| 32 | KBUILD_CFLAGS_DECOMPRESSOR += $(call cc-disable-warning, address-of-packed-member) | 32 | KBUILD_CFLAGS_DECOMPRESSOR += $(call cc-disable-warning, address-of-packed-member) |
| 33 | KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO),-g) | 33 | KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO),-g) |
| 34 | KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO_DWARF4), $(call cc-option, -gdwarf-4,)) | 34 | KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO_DWARF4), $(call cc-option, -gdwarf-4,)) |
| 35 | 35 | KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_CC_NO_ARRAY_BOUNDS),-Wno-array-bounds) | |
| 36 | ifdef CONFIG_CC_IS_GCC | ||
| 37 | ifeq ($(call cc-ifversion, -ge, 1200, y), y) | ||
| 38 | ifeq ($(call cc-ifversion, -lt, 1300, y), y) | ||
| 39 | KBUILD_CFLAGS += $(call cc-disable-warning, array-bounds) | ||
| 40 | KBUILD_CFLAGS_DECOMPRESSOR += $(call cc-disable-warning, array-bounds) | ||
| 41 | endif | ||
| 42 | endif | ||
| 43 | endif | ||
| 44 | 36 | ||
| 45 | UTS_MACHINE := s390x | 37 | UTS_MACHINE := s390x |
| 46 | STACK_SIZE := $(if $(CONFIG_KASAN),65536,16384) | 38 | STACK_SIZE := $(if $(CONFIG_KASAN),65536,16384) |
| @@ -885,6 +885,15 @@ config CC_IMPLICIT_FALLTHROUGH · 884 unmodified lines | |||
| 885 | default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) | 885 | default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) |
| 886 | default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) | 886 | default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) |
| 887 | 887 | ||
| 888 | # Currently, disable gcc-12 array-bounds globally. | ||
| 889 | # We may want to target only particular configurations some day. | ||
| 890 | config GCC12_NO_ARRAY_BOUNDS | ||
| 891 | def_bool y | ||
| 892 | |||
| 893 | config CC_NO_ARRAY_BOUNDS | ||
| 894 | bool | ||
| 895 | default y if CC_IS_GCC && GCC_VERSION >= 120000 && GCC_VERSION < 130000 && GCC12_NO_ARRAY_BOUNDS | ||
| 896 | |||
| 888 | # | 897 | # |
| 889 | # For architectures that know their GCC __int128 support is sound | 898 | # For architectures that know their GCC __int128 support is sound |
| 890 | # | 899 | # |