Fix sparse checks processing

A lot of errors are encountered when building with sparse checking
activated (make C=1 or make C=2).

Many of them are fixed in Linux.

Resynchronise Makefile and include/linux/build_bug.h with Linux
kernel sources by porting the following Linux commits into u-boot:
- 6c49f359ca14 ("kbuild: disable sparse warnings about unknown attributes")
- 80591e61a0f7 ("kbuild: tell sparse about the $ARCH")
- 8788994376d8 ("linux/build_bug.h: change type to int")
- 527edbc18a70 ("build_bug.h: remove most of dummy BUILD_BUG_ON stubs for Sparse")
- c60d3b79423a ("build_bug.h: remove negative-array fallback for BUILD_BUG_ON()")
- 14e83077d55f ("include: drop pointless __compiler_offsetof indirection")

Also revert commit aa9e891c63 ("include/linux/stddef.h: avoid
'warning: preprocessor token offsetof redefined'") because the
error it creates is worse than the warning it is trying to fix.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>

1 files changed, 5 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index fb02bba08fb..3f5249ceb52 100644
--- a/Makefile
+++ b/Makefile
@@ -423,7 +423,8 @@ DTC_MIN_VERSION	:= 010406
 CHECK		= sparse
 
 CHECKFLAGS     := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \
-		  -Wbitwise -Wno-return-void -D__CHECK_ENDIAN__ $(CF)
+		  -Wbitwise -Wno-return-void -Wno-unknown-attribute \
+		  -D__CHECK_ENDIAN__ $(CF)
 
 KBUILD_CPPFLAGS := -D__KERNEL__ -D__UBOOT__
 
@@ -1032,6 +1033,9 @@ ifeq ($(CONFIG_ARC)$(CONFIG_NIOS2)$(CONFIG_X86)$(CONFIG_XTENSA),)
 LDFLAGS_u-boot += -Ttext $(CONFIG_TEXT_BASE)
 endif
 
+# make the checker run with the right architecture
+CHECKFLAGS += --arch=$(ARCH)
+
 # insure the checker run with the right endianness
 CHECKFLAGS += $(if $(CONFIG_CPU_BIG_ENDIAN),-mbig-endian,-mlittle-endian)