kbuild: make -Woverride-init warnings more consistent

The -Woverride-init warn about code that may be intentional or not,
but the inintentional ones tend to be real bugs, so there is a bit of
disagreement on whether this warning option should be enabled by default
and we have multiple settings in scripts/Makefile.extrawarn as well as
individual subsystems.

Older versions of clang only supported -Wno-initializer-overrides with
the same meaning as gcc's -Woverride-init, though all supported versions
now work with both. Because of this difference, an earlier cleanup of
mine accidentally turned the clang warning off for W=1 builds and only
left it on for W=2, while it's still enabled for gcc with W=1.

There is also one driver that only turns the warning off for newer
versions of gcc but not other compilers, and some but not all the
Makefiles still use a cc-disable-warning conditional that is no
longer needed with supported compilers here.

Address all of the above by removing the special cases for clang
and always turning the warning off unconditionally where it got
in the way, using the syntax that is supported by both compilers.

Fixes: 2cd3271b7a31 ("kbuild: avoid duplicate warning options")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Andrew Jeffery <andrew@codeconstruct.com.au>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

drivers/gpu/drm/amd/display/dc/dce110/Makefile

@@ -23,7 +23,7 @@
 # Makefile for the 'controller' sub-component of DAL.
 # It provides the control and status of HW CRTC block.
 
-CFLAGS_$(AMDDALPATH)/dc/dce110/dce110_resource.o = $(call cc-disable-warning, override-init)
+CFLAGS_$(AMDDALPATH)/dc/dce110/dce110_resource.o = -Wno-override-init
 
 DCE110 = dce110_timing_generator.o \
 dce110_compressor.o dce110_opp_regamma_v.o \

drivers/gpu/drm/amd/display/dc/dce112/Makefile

@@ -23,7 +23,7 @@
 # Makefile for the 'controller' sub-component of DAL.
 # It provides the control and status of HW CRTC block.
 
-CFLAGS_$(AMDDALPATH)/dc/dce112/dce112_resource.o = $(call cc-disable-warning, override-init)
+CFLAGS_$(AMDDALPATH)/dc/dce112/dce112_resource.o = -Wno-override-init
 
 DCE112 = dce112_compressor.o
 

drivers/gpu/drm/amd/display/dc/dce120/Makefile

@@ -24,7 +24,7 @@
 # It provides the control and status of HW CRTC block.
 
 
-CFLAGS_$(AMDDALPATH)/dc/dce120/dce120_resource.o = $(call cc-disable-warning, override-init)
+CFLAGS_$(AMDDALPATH)/dc/dce120/dce120_resource.o = -Wno-override-init
 
 DCE120 = dce120_timing_generator.o
 

drivers/gpu/drm/amd/display/dc/dce60/Makefile

@@ -23,7 +23,7 @@
 # Makefile for the 'controller' sub-component of DAL.
 # It provides the control and status of HW CRTC block.
 
-CFLAGS_$(AMDDALPATH)/dc/dce60/dce60_resource.o = $(call cc-disable-warning, override-init)
+CFLAGS_$(AMDDALPATH)/dc/dce60/dce60_resource.o = -Wno-override-init
 
 DCE60 = dce60_timing_generator.o dce60_hw_sequencer.o \
 	dce60_resource.o

drivers/gpu/drm/amd/display/dc/dce80/Makefile

@@ -23,7 +23,7 @@
 # Makefile for the 'controller' sub-component of DAL.
 # It provides the control and status of HW CRTC block.
 
-CFLAGS_$(AMDDALPATH)/dc/dce80/dce80_resource.o = $(call cc-disable-warning, override-init)
+CFLAGS_$(AMDDALPATH)/dc/dce80/dce80_resource.o = -Wno-override-init
 
 DCE80 = dce80_timing_generator.o
 

drivers/gpu/drm/i915/Makefile

@@ -33,9 +33,9 @@ endif
 subdir-ccflags-$(CONFIG_DRM_I915_WERROR) += -Werror
 
 # Fine grained warnings disable
-CFLAGS_i915_pci.o = $(call cc-disable-warning, override-init)
+CFLAGS_i915_pci.o = -Wno-override-init
-CFLAGS_display/intel_display_device.o = $(call cc-disable-warning, override-init)
+CFLAGS_display/intel_display_device.o = -Wno-override-init
-CFLAGS_display/intel_fbdev.o = $(call cc-disable-warning, override-init)
+CFLAGS_display/intel_fbdev.o = -Wno-override-init
 
 # Support compiling the display code separately for both i915 and xe
 # drivers. Define I915 when building i915.

drivers/gpu/drm/xe/Makefile

@@ -172,8 +172,8 @@ subdir-ccflags-$(CONFIG_DRM_XE_DISPLAY) += \
 	-Ddrm_i915_gem_object=xe_bo \
 	-Ddrm_i915_private=xe_device
 
-CFLAGS_i915-display/intel_fbdev.o = $(call cc-disable-warning, override-init)
+CFLAGS_i915-display/intel_fbdev.o = -Wno-override-init
-CFLAGS_i915-display/intel_display_device.o = $(call cc-disable-warning, override-init)
+CFLAGS_i915-display/intel_display_device.o = -Wno-override-init
 
 # Rule to build SOC code shared with i915
 $(obj)/i915-soc/%.o: $(srctree)/drivers/gpu/drm/i915/soc/%.c FORCE

drivers/net/ethernet/renesas/sh_eth.c

@@ -50,7 +50,7 @@
  * the macros available to do this only define GCC 8.
  */
 __diag_push();
-__diag_ignore(GCC, 8, "-Woverride-init",
+__diag_ignore_all("-Woverride-init",
 	      "logic to initialize all and then override some is OK");
 static const u16 sh_eth_offset_gigabit[SH_ETH_MAX_REGISTER_OFFSET] = {
 	SH_ETH_OFFSET_DEFAULTS,

drivers/pinctrl/aspeed/Makefile

@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 # Aspeed pinctrl support
 
-ccflags-y += $(call cc-option,-Woverride-init)
+ccflags-y += -Woverride-init
 obj-$(CONFIG_PINCTRL_ASPEED)	+= pinctrl-aspeed.o pinmux-aspeed.o
 obj-$(CONFIG_PINCTRL_ASPEED_G4)	+= pinctrl-aspeed-g4.o
 obj-$(CONFIG_PINCTRL_ASPEED_G5)	+= pinctrl-aspeed-g5.o

fs/proc/Makefile

@@ -5,7 +5,7 @@
 
 obj-y   += proc.o
 
-CFLAGS_task_mmu.o	+= $(call cc-option,-Wno-override-init,)
+CFLAGS_task_mmu.o	+= -Wno-override-init
 proc-y			:= nommu.o task_nommu.o
 proc-$(CONFIG_MMU)	:= task_mmu.o
 

kernel/bpf/Makefile

@@ -4,7 +4,7 @@ ifneq ($(CONFIG_BPF_JIT_ALWAYS_ON),y)
 # ___bpf_prog_run() needs GCSE disabled on x86; see 3193c0836f203 for details
 cflags-nogcse-$(CONFIG_X86)$(CONFIG_CC_IS_GCC) := -fno-gcse
 endif
-CFLAGS_core.o += $(call cc-disable-warning, override-init) $(cflags-nogcse-yy)
+CFLAGS_core.o += -Wno-override-init $(cflags-nogcse-yy)
 
 obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o log.o token.o
 obj-$(CONFIG_BPF_SYSCALL) += bpf_iter.o map_iter.o task_iter.o prog_iter.o link_iter.o

mm/Makefile

@@ -29,8 +29,7 @@ KCOV_INSTRUMENT_mmzone.o := n
 KCOV_INSTRUMENT_vmstat.o := n
 KCOV_INSTRUMENT_failslab.o := n
 
-CFLAGS_init-mm.o += $(call cc-disable-warning, override-init)
+CFLAGS_init-mm.o += -Wno-override-init
-CFLAGS_init-mm.o += $(call cc-disable-warning, initializer-overrides)
 
 mmu-y			:= nommu.o
 mmu-$(CONFIG_MMU)	:= highmem.o memory.o mincore.o \

scripts/Makefile.extrawarn

@@ -114,6 +114,8 @@ KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow)
 KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation)
 KBUILD_CFLAGS += $(call cc-disable-warning, stringop-truncation)
 
+KBUILD_CFLAGS += -Wno-override-init # alias for -Wno-initializer-overrides in clang
+
 ifdef CONFIG_CC_IS_CLANG
 # Clang before clang-16 would warn on default argument promotions.
 ifneq ($(call clang-min-version, 160000),y)
@@ -151,10 +153,6 @@ KBUILD_CFLAGS += -Wtype-limits
 KBUILD_CFLAGS += $(call cc-option, -Wmaybe-uninitialized)
 KBUILD_CFLAGS += $(call cc-option, -Wunused-macros)
 
-ifdef CONFIG_CC_IS_CLANG
-KBUILD_CFLAGS += -Winitializer-overrides
-endif
-
 KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN2
 
 else
@@ -164,9 +162,7 @@ KBUILD_CFLAGS += -Wno-missing-field-initializers
 KBUILD_CFLAGS += -Wno-type-limits
 KBUILD_CFLAGS += -Wno-shift-negative-value
 
-ifdef CONFIG_CC_IS_CLANG
+ifdef CONFIG_CC_IS_GCC
-KBUILD_CFLAGS += -Wno-initializer-overrides
-else
 KBUILD_CFLAGS += -Wno-maybe-uninitialized
 endif