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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@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <Konrad.wilk@oracle.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
This commit is contained in:
Daniel Kiper 2014-07-12 23:09:48 +02:00 committed by Matt Fleming
parent 57f7138d76
commit c7341d6a61
4 changed files with 53 additions and 14 deletions
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1
arch/x86/xen/Makefile
View File

@ -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

43
arch/x86/xen/efi.c Normal file
View File

@ -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);
}

15
arch/x86/xen/enlighten.c
View File

@ -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

8
arch/x86/xen/xen-ops.h
View File

@ -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, ...) \