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=-13.5 required=3.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED,DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 634F3C433ED for ; Tue, 18 May 2021 09:07:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 46A7D60720 for ; Tue, 18 May 2021 09:07:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347791AbhERJJN (ORCPT ); Tue, 18 May 2021 05:09:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37606 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347725AbhERJI2 (ORCPT ); Tue, 18 May 2021 05:08:28 -0400 Received: from mail-wr1-x431.google.com (mail-wr1-x431.google.com [IPv6:2a00:1450:4864:20::431]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A5D6EC061345 for ; Tue, 18 May 2021 02:07:10 -0700 (PDT) Received: by mail-wr1-x431.google.com with SMTP id v12so9329551wrq.6 for ; Tue, 18 May 2021 02:07:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=9rGi608qIyo5wwTAfm/9KSh42lmNIqRVhptkNqcqKak=; b=boNwMh1++w7TDzmUAg3tAWQaAtUpXq0nkaVL4P8ywlxWnnj3GizxF9D5FCopHzYH0l M392UtjwRQdiPZV4Nn5JI2GOdJ+18ZnwwY/Yc6DCynMepnDHLpTnHR3bvKPB7oR+QqB3 NBfxlbpLCIbfsyf5AfcoHUKdJmvEg7e3mj7gSeG+XZjVzDwRkLWQrIb6xdqcAXzDQK9C 2W6K257G0wB0LkXgThuBcB8JyHIKqqpKgI0qn8GOQ1KhMSM5Vqr5kOxyNL290VammKg/ t4LRWs1m68gYzNU0jl8giZsH9bb5PWDXWl4afmWTENaBJ7sJmnugegUMu/LWG9Hs/JXo 7tow== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=9rGi608qIyo5wwTAfm/9KSh42lmNIqRVhptkNqcqKak=; b=cMtsA/rFIyPHpHuI0AOpCGwMhwwJHMeIV7/BW7viVefqJndyF+Nyj/BLsrE048eG7w 85Lj3/onpx+BeCd+yVRzXrb/sKIaE1Koo2fI36x9UAv/74ZQ/QSeKucKl+gAb9hu+ZmI TheEE6KwcOpv3jTEIHX43RypyqamH/KoZWYETRyYiWstF89u7hNArZsUcO5fWlf22ZZ2 /6/kcctSvBNo9jEnCncTR/0zmjq7aqurFSxlgsXVcmMyr63dvgk3Jc2zxVIue4CPBwtt 3Tu/cUrkU4ZSHcYAdsbkmwd85gvMQHHINb3tZzkLEWg4Ac8Z+q6z/JHZBJ1MAgFIBncx kzMA== X-Gm-Message-State: AOAM5317JXsi8ZNXi0E0pM+BkOhjGI0KRqQPUOttBoCXPADfXwN3Blxl UfCxKuFfbh9W1CwtzA8Gp4gOyHNvv2rnS7g+ X-Google-Smtp-Source: ABdhPJwS9MdO+Qwxpqf9XZbH6OCB7DYTmx7uZPYqKcZVbpPMaJnWz94YV9xSRF/j8QdMOHfyvwkbnw== X-Received: by 2002:a5d:658e:: with SMTP id q14mr5355475wru.81.1621328829488; Tue, 18 May 2021 02:07:09 -0700 (PDT) Received: from amanieu-laptop.home ([2a00:23c6:f081:f801:91cf:b949:c46c:f5a9]) by smtp.gmail.com with ESMTPSA id z17sm7520306wrt.81.2021.05.18.02.07.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 18 May 2021 02:07:08 -0700 (PDT) From: Amanieu d'Antras Cc: Amanieu d'Antras , Ryan Houdek , Catalin Marinas , Will Deacon , Mark Rutland , Steven Price , Arnd Bergmann , David Laight , Mark Brown , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [RESEND PATCH v4 3/8] mm: Support mmap_compat_base with the generic layout Date: Tue, 18 May 2021 10:06:53 +0100 Message-Id: <20210518090658.9519-4-amanieu@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210518090658.9519-1-amanieu@gmail.com> References: <20210518090658.9519-1-amanieu@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This enables architectures using the generic mmap layout to support 32-bit mmap calls from 64-bit processes and vice-versa. Architectures using this must define separate 32-bit and 64-bit versions of STACK_TOP, TASK_UNMAPPED_BASE and STACK_RND_MASK. Signed-off-by: Amanieu d'Antras Co-developed-by: Ryan Houdek Signed-off-by: Ryan Houdek --- mm/util.c | 46 ++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 38 insertions(+), 8 deletions(-) diff --git a/mm/util.c b/mm/util.c index 54870226cea6..37bd764174b5 100644 --- a/mm/util.c +++ b/mm/util.c @@ -353,12 +353,12 @@ unsigned long arch_randomize_brk(struct mm_struct *mm) return randomize_page(mm->brk, SZ_1G); } -unsigned long arch_mmap_rnd(void) +static unsigned long mmap_rnd(bool compat) { unsigned long rnd; #ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS - if (is_compat_task()) + if (compat) rnd = get_random_long() & ((1UL << mmap_rnd_compat_bits) - 1); else #endif /* CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS */ @@ -367,6 +367,11 @@ unsigned long arch_mmap_rnd(void) return rnd << PAGE_SHIFT; } +unsigned long arch_mmap_rnd(void) +{ + return mmap_rnd(is_compat_task()); +} + static int mmap_is_legacy(struct rlimit *rlim_stack) { if (current->personality & ADDR_COMPAT_LAYOUT) @@ -383,16 +388,17 @@ static int mmap_is_legacy(struct rlimit *rlim_stack) * the face of randomisation. */ #define MIN_GAP (SZ_128M) -#define MAX_GAP (STACK_TOP / 6 * 5) +#define MAX_GAP (stack_top / 6 * 5) -static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack) +static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack, + unsigned long stack_top, unsigned long stack_rnd_mask) { 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); + pad += (stack_rnd_mask << PAGE_SHIFT); /* Values close to RLIM_INFINITY can overflow. */ if (gap + pad > gap) @@ -403,21 +409,45 @@ static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack) else if (gap > MAX_GAP) gap = MAX_GAP; - return PAGE_ALIGN(STACK_TOP - gap - rnd); + return PAGE_ALIGN(stack_top - gap - rnd); } void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack) { unsigned long random_factor = 0UL; +#ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES + unsigned long compat_random_factor = 0UL; +#endif - if (current->flags & PF_RANDOMIZE) + if (current->flags & PF_RANDOMIZE) { +#ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES + random_factor = mmap_rnd(false); + compat_random_factor = mmap_rnd(true); +#else random_factor = arch_mmap_rnd(); +#endif + } if (mmap_is_legacy(rlim_stack)) { +#ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES + mm->mmap_base = TASK_UNMAPPED_BASE_64 + random_factor; + mm->mmap_compat_base = + TASK_UNMAPPED_BASE_32 + compat_random_factor; +#else mm->mmap_base = TASK_UNMAPPED_BASE + random_factor; +#endif mm->get_unmapped_area = arch_get_unmapped_area; } else { - mm->mmap_base = mmap_base(random_factor, rlim_stack); +#ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES + mm->mmap_base = mmap_base(random_factor, rlim_stack, + STACK_TOP_64, STACK_RND_MASK_64); + mm->mmap_compat_base = mmap_base(compat_random_factor, + rlim_stack, STACK_TOP_32, + STACK_RND_MASK_32); +#else + mm->mmap_base = mmap_base(random_factor, rlim_stack, STACK_TOP, + STACK_RND_MASK); +#endif mm->get_unmapped_area = arch_get_unmapped_area_topdown; } } -- 2.31.1