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arch/x86/xen: Silence compiler warnings

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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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15
arch/x86/xen/enlighten.c
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@@ -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