The patch titled Subject: Kbuild: use -fshort-wchar globally has been added to the -mm tree. Its filename is kbuild-use-fshort-wchar-globally.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/kbuild-use-fshort-wchar-globally.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/kbuild-use-fshort-wchar-globally.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Arnd Bergmann <arnd@xxxxxxxx> Subject: Kbuild: use -fshort-wchar globally A previous patch added the --no-wchar-size-warning to the Makefile to avoid this harmless warning: arm-linux-gnueabi-ld: warning: drivers/xen/efi.o uses 2-byte wchar_t yet the output is to use 4-byte wchar_t; use of wchar_t values across objects may fail Changing kbuild to use thin archives instead of recursive linking unfortunately brings the same warning back during the final link. The kernel does not use wchar_t string literals at this point, and xen does not use wchar_t at all (only efi_char16_t), so the flag has no effect, but as pointed out by Jan Beulich, adding a wchar_t string literal would be bad here. Since wchar_t is always defined as u16, independent of the toolchain default, always passing -fshort-wchar is correct and lets us remove the Xen specific hack along with fixing the warning. Link: http://lkml.kernel.org/r/20170726133655.2137437-1-arnd@xxxxxxxx Link: https://patchwork.kernel.org/patch/9275217/ Fixes: 971a69db7dc0 ("Xen: don't warn about 2-byte wchar_t in efi") Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Acked-by: David Vrabel <david.vrabel@xxxxxxxxxx> Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> Cc: Michal Marek <mmarek@xxxxxxxx> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> Cc: Juergen Gross <jgross@xxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Makefile | 2 +- drivers/xen/Makefile | 3 --- 2 files changed, 1 insertion(+), 4 deletions(-) diff -puN Makefile~kbuild-use-fshort-wchar-globally Makefile --- a/Makefile~kbuild-use-fshort-wchar-globally +++ a/Makefile @@ -396,7 +396,7 @@ LINUXINCLUDE := \ KBUILD_CPPFLAGS := -D__KERNEL__ KBUILD_CFLAGS := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \ - -fno-strict-aliasing -fno-common \ + -fno-strict-aliasing -fno-common -fshort-wchar \ -Werror-implicit-function-declaration \ -Wno-format-security \ -std=gnu89 $(call cc-option,-fno-PIE) diff -puN drivers/xen/Makefile~kbuild-use-fshort-wchar-globally drivers/xen/Makefile --- a/drivers/xen/Makefile~kbuild-use-fshort-wchar-globally +++ a/drivers/xen/Makefile @@ -7,9 +7,6 @@ obj-y += xenbus/ nostackp := $(call cc-option, -fno-stack-protector) CFLAGS_features.o := $(nostackp) -CFLAGS_efi.o += -fshort-wchar -LDFLAGS += $(call ld-option, --no-wchar-size-warning) - dom0-$(CONFIG_ARM64) += arm-device.o dom0-$(CONFIG_PCI) += pci.o dom0-$(CONFIG_USB_SUPPORT) += dbgp.o _ Patches currently in -mm which might be from arnd@xxxxxxxx are kasan-avoid-wmaybe-uninitialized-warning-v3.patch block-dac960-shut-up-format-overflow-warning.patch fscache-fix-fscache_objlist_show-format-processing.patch ib-mlx4-fix-sprintf-format-warning.patch iopoll-avoid-wint-in-bool-context-warning.patch kbuild-use-fshort-wchar-globally.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html