Kbuild: use -fshort-wchar globally

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>

diff --git a/Makefile b/Makefile
index 473f1aa76f6de7c44e3ec2f0c780df87c61b812f..4dac1107913bf9bf78fc0d68948aa9fdfe011e19 100644 (file)
--- a/Makefile
+++ b/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 --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