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>
Some bright sparks have decided that a cast on a constant cannot be a
constant, so offsetof() produces this warning on clang-10:
include/intel_gnvs.h:113:1: error: static_assert expression is not an
integral constant expression
check_member(acpi_global_nvs, unused2, GNVS_CHROMEOS_ACPI_OFFSET);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/kernel.h:284:2: note: expanded from macro 'check_member'
offsetof(struct structure, member) == (offset), \
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/stddef.h:20:32: note: expanded from macro 'offsetof'
^
include/intel_gnvs.h:113:1: note: cast that performs the conversions of
a reinterpret_cast is ot allowed in a constant expression
include/linux/stddef.h:20:33: note: expanded from macro 'offsetof'
Fix it by using the compiler built-in version, if available. This syncs
the function to the same implementation as Linux v5.16 in this header
file.
Signed-off-by: Simon Glass <sjg@chromium.org>
