Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755275AbaGKUCQ (ORCPT ); Fri, 11 Jul 2014 16:02:16 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:21420 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755027AbaGKUCP (ORCPT ); Fri, 11 Jul 2014 16:02:15 -0400 Message-ID: <53C04322.1050000@oracle.com> Date: Fri, 11 Jul 2014 16:03:46 -0400 From: Boris Ostrovsky User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Daniel Kiper , linux-kernel@vger.kernel.org, x86@kernel.org, xen-devel@lists.xenproject.org CC: andrew.cooper3@citrix.com, david.vrabel@citrix.com, hpa@zytor.com, ian.campbell@citrix.com, jbeulich@suse.com, jeremy@goop.org, konrad.wilk@oracle.com, matt.fleming@intel.com, mingo@redhat.com, stefano.stabellini@eu.citrix.com, tglx@linutronix.de Subject: Re: [PATCH 2/2] arch/x86/xen: Silence compiler warnings References: <1405108461-3223-1-git-send-email-daniel.kiper@oracle.com> <1405108461-3223-3-git-send-email-daniel.kiper@oracle.com> In-Reply-To: <1405108461-3223-3-git-send-email-daniel.kiper@oracle.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Source-IP: acsinet21.oracle.com [141.146.126.237] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/11/2014 03:54 PM, Daniel Kiper wrote: > 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 its body conditionally to avoid above > mentioned warning on x86 32-bit architecture. > > Signed-off-by: Daniel Kiper > --- > arch/x86/xen/enlighten.c | 35 ++++++++++++++++++++++------------- > 1 file changed, 22 insertions(+), 13 deletions(-) > > diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c > index bc89647..6abec74 100644 > --- a/arch/x86/xen/enlighten.c > +++ b/arch/x86/xen/enlighten.c > @@ -1516,12 +1516,32 @@ static void __init xen_pvh_early_guest_init(void) > #endif > } > > +static void __init xen_efi_init(void) > +{ > +#ifdef CONFIG_XEN_EFI > + 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); > +#endif > +} > + > /* First C function to be called on Xen boot */ > 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 +1737,7 @@ 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(); I'd put ifdef CONFIG_XEN_EFI around the call instead of having it inside the routine. -boris > > /* Start the world */ > #ifdef CONFIG_X86_32 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/