Kbuild: use -fshort-wchar globally

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>

diff --git a/Makefile b/Makefile
index c05f0762fd7ade6a6605b022abdcb187906b3a0a..1282afb5566b51102ce30ba055973dc7406589a3 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -394,7 +394,7 @@ LINUXINCLUDE        += $(filter-out $(LINUXINCLUDE),$(USERINCLUDE))
 
 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

diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 8feab810aed9222b97bd5959b42e6f09ffaaf83d..7f188b8d0c6703dda0ed4ae7647d7b082c429933 100644 (file)
--- 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