4.9-stable review patch. If anyone has any objections, please let me know.
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From: Arnd Bergmann arnd@arndb.de
commit 8c97023cf0518f172b8cb7a9fffc28b89401abbf upstream.
Commit 971a69db7dc0 ("Xen: don't warn about 2-byte wchar_t in efi") 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: 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@arndb.de Acked-by: David Vrabel david.vrabel@citrix.com Signed-off-by: Masahiro Yamada yamada.masahiro@socionext.com Signed-off-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- Makefile | 2 +- drivers/xen/Makefile | 3 --- 2 files changed, 1 insertion(+), 4 deletions(-)
--- a/Makefile +++ b/Makefile @@ -394,7 +394,7 @@ LINUXINCLUDE += $(filter-out $(LINUXINCL
KBUILD_AFLAGS := -D__ASSEMBLY__ 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 --- a/drivers/xen/Makefile +++ b/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