GCC 15 defaults to -std=gnu23. Hack in CSTD_FLAG to pass -std=gnu11

Signed-off-by: Mike Pagano <mpagano@gentoo.org>

2 files changed, 109 insertions, 0 deletions

diff --git a/0000_README b/0000_README
index 3ba43dfb..27b0205c 100644
--- a/0000_README
+++ b/0000_README
@@ -355,6 +355,10 @@ Patch:  2952_resolve-btfids-Fix-compiler-warnings.patch
 From:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/commit/?id=2c3d022abe6c3165109393b75a127b06c2c70063
 Desc:   resolve_btfids: Fix compiler warnings
 
+Patch:  2980_GCC15-gnu23-to-gnu11-fix.patch
+From:   https://lore.kernel.org/linux-kbuild/20241119044724.GA2246422@thelio-3990X/
+Desc:   GCC 15 defaults to -std=gnu23. Hack in CSTD_FLAG to pass -std=gnu11 everywhere.
+
 Patch:  2990_libbpf-v2-workaround-Wmaybe-uninitialized-false-pos.patch
 From:   https://lore.kernel.org/bpf/3ebbe7a4e93a5ddc3a26e2e11d329801d7c8de6b.1723217044.git.sam@gentoo.org/
 Desc:   libbpf: workaround -Wmaybe-uninitialized false positive
diff --git a/2980_GCC15-gnu23-to-gnu11-fix.patch b/2980_GCC15-gnu23-to-gnu11-fix.patch
new file mode 100644
index 00000000..1a4b594c
--- /dev/null
+++ b/2980_GCC15-gnu23-to-gnu11-fix.patch
@@ -0,0 +1,105 @@
+iGCC 15 defaults to -std=gnu23. While most of the kernel builds with -std=gnu11,
+some of it forgets to pass that flag. Hack in CSTD_FLAG to pass -std=gnu11
+everywhere.
+
+https://lore.kernel.org/linux-kbuild/20241119044724.GA2246422@thelio-3990X/
+--- a/Makefile
++++ b/Makefile
+@@ -416,6 +416,8 @@ export KCONFIG_CONFIG
+ # SHELL used by kbuild
+ CONFIG_SHELL := sh
+ 
++CSTD_FLAG := -std=gnu11
++
+ HOST_LFS_CFLAGS := $(shell getconf LFS_CFLAGS 2>/dev/null)
+ HOST_LFS_LDFLAGS := $(shell getconf LFS_LDFLAGS 2>/dev/null)
+ HOST_LFS_LIBS := $(shell getconf LFS_LIBS 2>/dev/null)
+@@ -437,7 +439,7 @@ HOSTRUSTC = rustc
+ HOSTPKG_CONFIG	= pkg-config
+ 
+ KBUILD_USERHOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \
+-			 -O2 -fomit-frame-pointer -std=gnu11
++			 -O2 -fomit-frame-pointer $(CSTD_FLAG)
+ KBUILD_USERCFLAGS  := $(KBUILD_USERHOSTCFLAGS) $(USERCFLAGS)
+ KBUILD_USERLDFLAGS := $(USERLDFLAGS)
+ 
+@@ -545,7 +547,7 @@ LINUXINCLUDE    := \
+ KBUILD_AFLAGS   := -D__ASSEMBLY__ -fno-PIE
+ 
+ KBUILD_CFLAGS :=
+-KBUILD_CFLAGS += -std=gnu11
++KBUILD_CFLAGS += $(CSTD_FLAG)
+ KBUILD_CFLAGS += -fshort-wchar
+ KBUILD_CFLAGS += -funsigned-char
+ KBUILD_CFLAGS += -fno-common
+@@ -589,7 +591,7 @@ export CPP AR NM STRIP OBJCOPY OBJDUMP READELF PAHOLE RESOLVE_BTFIDS LEX YACC AW
+ export PERL PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
+ export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ ZSTD
+ export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE
+-export KBUILD_USERCFLAGS KBUILD_USERLDFLAGS
++export KBUILD_USERCFLAGS KBUILD_USERLDFLAGS CSTD_FLAG
+ 
+ export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS
+ export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
+--- a/arch/arm64/kernel/vdso32/Makefile
++++ b/arch/arm64/kernel/vdso32/Makefile
+@@ -65,7 +65,7 @@ VDSO_CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
+                -fno-strict-aliasing -fno-common \
+                -Werror-implicit-function-declaration \
+                -Wno-format-security \
+-               -std=gnu11
++               $(CSTD_FLAG)
+ VDSO_CFLAGS  += -O2
+ # Some useful compiler-dependent flags from top-level Makefile
+ VDSO_CFLAGS += $(call cc32-option,-Wno-pointer-sign)
+--- a/arch/x86/Makefile	2024-11-19 14:12:02.692652332 -0500
++++ b/arch/x86/Makefile	2024-11-19 14:12:43.262934645 -0500
+@@ -43,7 +43,7 @@ endif
+ 
+ # How to compile the 16-bit code.  Note we always compile for -march=i386;
+ # that way we can complain to the user if the CPU is insufficient.
+-REALMODE_CFLAGS	:= -m16 -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS \
++REALMODE_CFLAGS  := $(CSTD_FLAG) -m16 -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS \
+ 		   -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \
+ 		   -fno-strict-aliasing -fomit-frame-pointer -fno-pic \
+ 		   -mno-mmx -mno-sse $(call cc-option,-fcf-protection=none)
+--- a/drivers/firmware/efi/libstub/Makefile
++++ b/drivers/firmware/efi/libstub/Makefile
+@@ -7,7 +7,7 @@
+ #
+ 
+ # non-x86 reuses KBUILD_CFLAGS, x86 does not
+-cflags-y			:= $(KBUILD_CFLAGS)
++cflags-y			:= $(KBUILD_CFLAGS) $(CSTD_FLAG)
+ 
+ cflags-$(CONFIG_X86_32)		:= -march=i386
+ cflags-$(CONFIG_X86_64)		:= -mcmodel=small
+@@ -18,7 +18,7 @@ cflags-$(CONFIG_X86)		+= -m$(BITS) -D__KERNEL__ \
+ 				   $(call cc-disable-warning, address-of-packed-member) \
+ 				   $(call cc-disable-warning, gnu) \
+ 				   -fno-asynchronous-unwind-tables \
+-				   $(CLANG_FLAGS)
++				   $(CLANG_FLAGS) $(CSTD_FLAG)
+ 
+ # arm64 uses the full KBUILD_CFLAGS so it's necessary to explicitly
+ # disable the stackleak plugin
+@@ -42,7 +42,7 @@ KBUILD_CFLAGS			:= $(subst $(CC_FLAGS_FTRACE),,$(cflags-y)) \
+ 				   -ffreestanding \
+ 				   -fno-stack-protector \
+ 				   $(call cc-option,-fno-addrsig) \
+-				   -D__DISABLE_EXPORTS
++				   -D__DISABLE_EXPORTS $(CSTD_FLAG)
+ 
+ #
+ # struct randomization only makes sense for Linux internal types, which the EFI
+--- a/arch/x86/boot/compressed/Makefile
++++ b/arch/x86/boot/compressed/Makefile
+@@ -24,7 +24,7 @@ targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \
+ # case of cross compiling, as it has the '--target=' flag, which is needed to
+ # avoid errors with '-march=i386', and future flags may depend on the target to
+ # be valid.
+-KBUILD_CFLAGS := -m$(BITS) -O2 $(CLANG_FLAGS)
++KBUILD_CFLAGS := -m$(BITS) -O2 $(CLANG_FLAGS) $(CSTD_FLAG)
+ KBUILD_CFLAGS += -fno-strict-aliasing -fPIE
+ KBUILD_CFLAGS += -Wundef
+ KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING