linux-kernel - [PATCH] Xen: don't warn about 2-byte wchar

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Date:	Wed, 11 May 2016 14:47:59 +0200
From:	Arnd Bergmann <arnd@...db.de>
To:	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	David Vrabel <david.vrabel@...rix.com>,
	Juergen Gross <jgross@...e.com>
Cc:	Arnd Bergmann <arnd@...db.de>,
	Stefano Stabellini <stefano.stabellini@...citrix.com>,
	Ian Campbell <ian.campbell@...rix.com>,
	Shannon Zhao <shannon.zhao@...aro.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org
Subject: [PATCH] Xen: don't warn about 2-byte wchar_t in efi

The XEN UEFI code has become available on the ARM architecture
recently, but now causes a link-time warning:

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

This seems harmless, because the efi code only uses 2-byte
characters when interacting with EFI, so we don't pass on those
strings to elsewhere in the system, and we just need to
silence the warning.

It is not clear to me whether we actually need to build the file
with the -fshort-wchar flag, but if we do, then we should also
pass --no-wchar-size-warning to the linker, to avoid the warning.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
Fixes: 37060935dc04 ("ARM64: XEN: Add a function to initialize Xen specific UEFI runtime services")
---
 drivers/xen/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 415f2869054b..8feab810aed9 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -8,6 +8,7 @@ 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
-- 
2.7.0