ubsan: enable for all*config builds

With UBSAN_OBJECT_SIZE disabled for GCC, only UBSAN_ALIGNMENT remained a
noisy UBSAN option.  Disable it for COMPILE_TEST so the rest of UBSAN can
be used for full all*config builds or other large combinations.

[sfr@canb.auug.org.au: add .data..Lubsan_data*/.data..Lubsan_type* sections explicitly]
  Link: https://lkml.kernel.org/r/20201208230157.42c42789@canb.auug.org.au

Link: https://lore.kernel.org/lkml/CAHk-=wgXW=YLxGN0QVpp-1w5GDd2pf1W-FqY15poKzoVfik2qA@mail.gmail.com/
Link: https://lkml.kernel.org/r/20201203004437.389959-6-keescook@chromium.orgSigned-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: George Popescu <georgepope@android.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Marco Elver <elver@google.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/powerpc/kernel/vmlinux.lds.S

@@ -313,6 +313,10 @@ SECTIONS
 #else
 	.data : AT(ADDR(.data) - LOAD_OFFSET) {
 		DATA_DATA
+#ifdef CONFIG_UBSAN
+		*(.data..Lubsan_data*)
+		*(.data..Lubsan_type*)
+#endif
 		*(.data.rel*)
 		*(.toc1)
 		*(.branch_lt)

lib/Kconfig.ubsan

@@ -130,7 +130,6 @@ config UBSAN_ENUM
 config UBSAN_SANITIZE_ALL
 	bool "Enable instrumentation for the entire kernel"
 	depends on ARCH_HAS_UBSAN_SANITIZE_ALL
-	depends on !COMPILE_TEST
 	default y
 	help
 	  This option activates instrumentation for the entire kernel.
@@ -142,7 +141,7 @@ config UBSAN_SANITIZE_ALL
 config UBSAN_ALIGNMENT
 	bool "Enable checks for pointers alignment"
 	default !HAVE_EFFICIENT_UNALIGNED_ACCESS
-	depends on !UBSAN_TRAP
+	depends on !UBSAN_TRAP && !COMPILE_TEST
 	depends on $(cc-option,-fsanitize=alignment)
 	help
 	  This option enables the check of unaligned memory accesses.