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Commit c7341d6a authored by Daniel Kiper's avatar Daniel Kiper Committed by Matt Fleming
Browse files

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: default avatarDaniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: default avatarKonrad Rzeszutek Wilk <Konrad.wilk@oracle.com>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
parent 57f7138d

arch/x86/xen/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/x86/xen/efi.c

0 → 100644
+43 −0
Original line number Diff line number Diff line 
/*

 * 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);

}

arch/x86/xen/enlighten.c

+1 −14
Original line number Diff line number Diff line
@@ -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

arch/x86/xen/xen-ops.h

+8 −0
Original line number Diff line number Diff line
@@ -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, ...)		\