From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 565F1C10F0B for ; Thu, 18 Apr 2019 06:06:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2454B204FD for ; Thu, 18 Apr 2019 06:06:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731254AbfDRGGQ (ORCPT ); Thu, 18 Apr 2019 02:06:16 -0400 Received: from relay11.mail.gandi.net ([217.70.178.231]:50541 "EHLO relay11.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725876AbfDRGGQ (ORCPT ); Thu, 18 Apr 2019 02:06:16 -0400 Received: from [192.168.0.11] (127.19.86.79.rev.sfr.net [79.86.19.127]) (Authenticated sender: alex@ghiti.fr) by relay11.mail.gandi.net (Postfix) with ESMTPSA id 6DE99100004; Thu, 18 Apr 2019 06:06:06 +0000 (UTC) Subject: Re: [PATCH v3 07/11] arm: Use generic mmap top-down layout To: Kees Cook Cc: Andrew Morton , Christoph Hellwig , Russell King , Catalin Marinas , Will Deacon , Ralf Baechle , Paul Burton , James Hogan , Palmer Dabbelt , Albert Ou , Alexander Viro , Luis Chamberlain , LKML , linux-arm-kernel , linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org, "linux-fsdevel@vger.kernel.org" , Linux-MM References: <20190417052247.17809-1-alex@ghiti.fr> <20190417052247.17809-8-alex@ghiti.fr> From: Alex Ghiti Message-ID: <5d0385b0-c03b-f4c7-45fa-4d97677cf816@ghiti.fr> Date: Thu, 18 Apr 2019 02:06:06 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: sv-FI Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 4/18/19 1:28 AM, Kees Cook wrote: > On Wed, Apr 17, 2019 at 12:30 AM Alexandre Ghiti wrote: >> arm uses a top-down mmap layout by default that exactly fits the generic >> functions, so get rid of arch specific code and use the generic version >> by selecting ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT. >> >> Signed-off-by: Alexandre Ghiti > Acked-by: Kees Cook Thanks ! > > -Kees > >> --- >> arch/arm/Kconfig | 1 + >> arch/arm/include/asm/processor.h | 2 -- >> arch/arm/mm/mmap.c | 62 -------------------------------- >> 3 files changed, 1 insertion(+), 64 deletions(-) >> >> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig >> index 850b4805e2d1..f8f603da181f 100644 >> --- a/arch/arm/Kconfig >> +++ b/arch/arm/Kconfig >> @@ -28,6 +28,7 @@ config ARM >> select ARCH_SUPPORTS_ATOMIC_RMW >> select ARCH_USE_BUILTIN_BSWAP >> select ARCH_USE_CMPXCHG_LOCKREF >> + select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU >> select ARCH_WANT_IPC_PARSE_VERSION >> select BUILDTIME_EXTABLE_SORT if MMU >> select CLONE_BACKWARDS >> diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h >> index 57fe73ea0f72..944ef1fb1237 100644 >> --- a/arch/arm/include/asm/processor.h >> +++ b/arch/arm/include/asm/processor.h >> @@ -143,8 +143,6 @@ static inline void prefetchw(const void *ptr) >> #endif >> #endif >> >> -#define HAVE_ARCH_PICK_MMAP_LAYOUT >> - >> #endif >> >> #endif /* __ASM_ARM_PROCESSOR_H */ >> diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c >> index 0b94b674aa91..b8d912ac9e61 100644 >> --- a/arch/arm/mm/mmap.c >> +++ b/arch/arm/mm/mmap.c >> @@ -17,43 +17,6 @@ >> ((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \ >> (((pgoff)<> >> -/* gap between mmap and stack */ >> -#define MIN_GAP (128*1024*1024UL) >> -#define MAX_GAP ((STACK_TOP)/6*5) >> -#define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12)) >> - >> -static int mmap_is_legacy(struct rlimit *rlim_stack) >> -{ >> - if (current->personality & ADDR_COMPAT_LAYOUT) >> - return 1; >> - >> - if (rlim_stack->rlim_cur == RLIM_INFINITY) >> - return 1; >> - >> - return sysctl_legacy_va_layout; >> -} >> - >> -static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack) >> -{ >> - unsigned long gap = rlim_stack->rlim_cur; >> - unsigned long pad = stack_guard_gap; >> - >> - /* Account for stack randomization if necessary */ >> - if (current->flags & PF_RANDOMIZE) >> - pad += (STACK_RND_MASK << PAGE_SHIFT); >> - >> - /* Values close to RLIM_INFINITY can overflow. */ >> - if (gap + pad > gap) >> - gap += pad; >> - >> - if (gap < MIN_GAP) >> - gap = MIN_GAP; >> - else if (gap > MAX_GAP) >> - gap = MAX_GAP; >> - >> - return PAGE_ALIGN(STACK_TOP - gap - rnd); >> -} >> - >> /* >> * We need to ensure that shared mappings are correctly aligned to >> * avoid aliasing issues with VIPT caches. We need to ensure that >> @@ -181,31 +144,6 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, >> return addr; >> } >> >> -unsigned long arch_mmap_rnd(void) >> -{ >> - unsigned long rnd; >> - >> - rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1); >> - >> - return rnd << PAGE_SHIFT; >> -} >> - >> -void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack) >> -{ >> - unsigned long random_factor = 0UL; >> - >> - if (current->flags & PF_RANDOMIZE) >> - random_factor = arch_mmap_rnd(); >> - >> - if (mmap_is_legacy(rlim_stack)) { >> - mm->mmap_base = TASK_UNMAPPED_BASE + random_factor; >> - mm->get_unmapped_area = arch_get_unmapped_area; >> - } else { >> - mm->mmap_base = mmap_base(random_factor, rlim_stack); >> - mm->get_unmapped_area = arch_get_unmapped_area_topdown; >> - } >> -} >> - >> /* >> * You really shouldn't be using read() or write() on /dev/mem. This >> * might go away in the future. >> -- >> 2.20.1 >> >