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Date: Sat, 12 Jul 2014 23:09:48 +0200
From: Daniel Kiper <daniel.kiper@...cle.com>
To: linux-kernel@...r.kernel.org, x86@...nel.org,
xen-devel@...ts.xenproject.org
Cc: andrew.cooper3@...rix.com, boris.ostrovsky@...cle.com,
david.vrabel@...rix.com, hpa@...or.com, ian.campbell@...rix.com,
jbeulich@...e.com, jeremy@...p.org, konrad.wilk@...cle.com,
matt.fleming@...el.com, mingo@...hat.com,
stefano.stabellini@...citrix.com, tglx@...utronix.de
Subject: [PATCH v2 2/2] arch/x86/xen: Silence compiler warnings
Compiler complains in the following way when x86 32-bit kernel
with Xen support is build:
CC arch/x86/xen/enlighten.o
arch/x86/xen/enlighten.c: In function ‘xen_start_kernel’:
arch/x86/xen/enlighten.c:1726:3: warning: right shift count >= width of type [enabled by default]
Such line contains following EFI initialization code:
boot_params.efi_info.efi_systab_hi = (__u32)(__pa(efi_systab_xen) >> 32);
There is no issue if x86 64-bit kernel is build. However, 32-bit case
generate warning (even if that code will not be executed because Xen
does not work on 32-bit EFI platforms) due to __pa() returning unsigned long
type which has 32-bits width. So move whole EFI initialization stuff
to separate function and build it conditionally to avoid above mentioned
warning on x86 32-bit architecture.
Signed-off-by: Daniel Kiper <daniel.kiper@...cle.com>
---
v2 - suggestions/fixes:
- move xen_efi_init() to separate module
(suggested by Konrad Rzeszutek Wilk).
---
arch/x86/xen/Makefile | 1 +
arch/x86/xen/efi.c | 43 +++++++++++++++++++++++++++++++++++++++++++
arch/x86/xen/enlighten.c | 15 +--------------
arch/x86/xen/xen-ops.h | 8 ++++++++
4 files changed, 53 insertions(+), 14 deletions(-)
create mode 100644 arch/x86/xen/efi.c
diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
index 96ab2c0..7322755 100644
--- a/arch/x86/xen/Makefile
+++ b/arch/x86/xen/Makefile
@@ -22,3 +22,4 @@ obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= spinlock.o
obj-$(CONFIG_XEN_DEBUG_FS) += debugfs.o
obj-$(CONFIG_XEN_DOM0) += apic.o vga.o
obj-$(CONFIG_SWIOTLB_XEN) += pci-swiotlb-xen.o
+obj-$(CONFIG_XEN_EFI) += efi.o
diff --git a/arch/x86/xen/efi.c b/arch/x86/xen/efi.c
new file mode 100644
index 0000000..a02e09e
--- /dev/null
+++ b/arch/x86/xen/efi.c
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2014 Oracle Co., Daniel Kiper
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/efi.h>
+#include <linux/init.h>
+#include <linux/string.h>
+
+#include <xen/xen-ops.h>
+
+#include <asm/setup.h>
+
+void __init xen_efi_init(void)
+{
+ efi_system_table_t *efi_systab_xen;
+
+ efi_systab_xen = xen_efi_probe();
+
+ if (efi_systab_xen == NULL)
+ return;
+
+ strncpy((char *)&boot_params.efi_info.efi_loader_signature, "Xen",
+ sizeof(boot_params.efi_info.efi_loader_signature));
+ boot_params.efi_info.efi_systab = (__u32)__pa(efi_systab_xen);
+ boot_params.efi_info.efi_systab_hi = (__u32)(__pa(efi_systab_xen) >> 32);
+
+ set_bit(EFI_BOOT, &efi.flags);
+ set_bit(EFI_PARAVIRT, &efi.flags);
+ set_bit(EFI_64BIT, &efi.flags);
+}
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index bc89647..2cd0463 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -32,7 +32,6 @@
#include <linux/gfp.h>
#include <linux/memblock.h>
#include <linux/edd.h>
-#include <linux/efi.h>
#include <xen/xen.h>
#include <xen/events.h>
@@ -1521,7 +1520,6 @@ asmlinkage __visible void __init xen_start_kernel(void)
{
struct physdev_set_iopl set_iopl;
int rc;
- efi_system_table_t *efi_systab_xen;
if (!xen_start_info)
return;
@@ -1717,18 +1715,7 @@ asmlinkage __visible void __init xen_start_kernel(void)
xen_setup_runstate_info(0);
- efi_systab_xen = xen_efi_probe();
-
- if (efi_systab_xen) {
- strncpy((char *)&boot_params.efi_info.efi_loader_signature, "Xen",
- sizeof(boot_params.efi_info.efi_loader_signature));
- boot_params.efi_info.efi_systab = (__u32)__pa(efi_systab_xen);
- boot_params.efi_info.efi_systab_hi = (__u32)(__pa(efi_systab_xen) >> 32);
-
- set_bit(EFI_BOOT, &efi.flags);
- set_bit(EFI_PARAVIRT, &efi.flags);
- set_bit(EFI_64BIT, &efi.flags);
- }
+ xen_efi_init();
/* Start the world */
#ifdef CONFIG_X86_32
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index c834d4b..75f98fe 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -104,6 +104,14 @@ static inline void __init xen_init_apic(void)
}
#endif
+#ifdef CONFIG_XEN_EFI
+extern void xen_efi_init(void);
+#else
+static inline void __init xen_efi_init(void)
+{
+}
+#endif
+
/* Declare an asm function, along with symbols needed to make it
inlineable */
#define DECL_ASM(ret, name, ...) \
--
1.7.10.4
--
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