From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753522AbbCZWfj (ORCPT ); Thu, 26 Mar 2015 18:35:39 -0400 Received: from mail.kernel.org ([198.145.29.136]:53087 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751900AbbCZWfh (ORCPT ); Thu, 26 Mar 2015 18:35:37 -0400 Message-ID: <551489B1.9020708@kernel.org> Date: Thu, 26 Mar 2015 15:35:29 -0700 From: Andy Lutomirski User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Dave Hansen , linux-kernel@vger.kernel.org CC: x86@kernel.org, tglx@linutronix.de, dave.hansen@linux.intel.com, oleg@redhat.com Subject: Re: [PATCH 09/17] x86: make is_64bit_mm() widely available References: <20150326183327.64807530@viggo.jf.intel.com> <20150326183345.6727B83D@viggo.jf.intel.com> In-Reply-To: <20150326183345.6727B83D@viggo.jf.intel.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/26/2015 11:33 AM, Dave Hansen wrote: > From: Dave Hansen > > The uprobes code has a nice helper, is_64bit_mm(), that consults both > the runtime and compile-time flags for 32-bit support. Instead of > reinventing the wheel, pull it in to an x86 header so we can use it > for MPX. > > I prefer passing the mm around to test_thread_flag(TIF_IA32) beacuse > it makes it explicit where the context is coming from. It will also > make it easier if we ever need to access the MPX structures from > another process. > > Signed-off-by: Dave Hansen > Cc: Oleg Nesterov I like this. Maybe we can remove TIF_IA32 entirely at some point based on this :) > --- > > b/arch/x86/include/asm/mmu_context.h | 13 +++++++++++++ > b/arch/x86/kernel/uprobes.c | 10 +--------- > 2 files changed, 14 insertions(+), 9 deletions(-) > > diff -puN arch/x86/include/asm/mmu_context.h~x86-make-is_64bit_mm-available arch/x86/include/asm/mmu_context.h > --- a/arch/x86/include/asm/mmu_context.h~x86-make-is_64bit_mm-available 2015-03-26 11:27:31.685419698 -0700 > +++ b/arch/x86/include/asm/mmu_context.h 2015-03-26 11:27:31.690419923 -0700 > @@ -142,6 +142,19 @@ static inline void arch_exit_mmap(struct > paravirt_arch_exit_mmap(mm); > } > > +#ifdef CONFIG_X86_64 > +static inline bool is_64bit_mm(struct mm_struct *mm) > +{ > + return !config_enabled(CONFIG_IA32_EMULATION) || > + !(mm->context.ia32_compat == TIF_IA32); > +} > +#else > +static inline bool is_64bit_mm(struct mm_struct *mm) > +{ > + return false; > +} > +#endif > + > static inline void arch_bprm_mm_init(struct mm_struct *mm, > struct vm_area_struct *vma) > { > diff -puN arch/x86/kernel/uprobes.c~x86-make-is_64bit_mm-available arch/x86/kernel/uprobes.c > --- a/arch/x86/kernel/uprobes.c~x86-make-is_64bit_mm-available 2015-03-26 11:27:31.687419788 -0700 > +++ b/arch/x86/kernel/uprobes.c 2015-03-26 11:27:31.690419923 -0700 > @@ -29,6 +29,7 @@ > #include > #include > #include > +#include > > /* Post-execution fixups. */ > > @@ -312,11 +313,6 @@ static int uprobe_init_insn(struct arch_ > } > > #ifdef CONFIG_X86_64 > -static inline bool is_64bit_mm(struct mm_struct *mm) > -{ > - return !config_enabled(CONFIG_IA32_EMULATION) || > - !(mm->context.ia32_compat == TIF_IA32); > -} > /* > * If arch_uprobe->insn doesn't use rip-relative addressing, return > * immediately. Otherwise, rewrite the instruction so that it accesses > @@ -497,10 +493,6 @@ static void riprel_post_xol(struct arch_ > } > } > #else /* 32-bit: */ > -static inline bool is_64bit_mm(struct mm_struct *mm) > -{ > - return false; > -} > /* > * No RIP-relative addressing on 32-bit > */ > _ >