From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f71.google.com (mail-it0-f71.google.com [209.85.214.71]) by kanga.kvack.org (Postfix) with ESMTP id AC7306B03B2 for ; Tue, 14 Feb 2017 13:40:25 -0500 (EST) Received: by mail-it0-f71.google.com with SMTP id h10so39801569ith.2 for ; Tue, 14 Feb 2017 10:40:25 -0800 (PST) Received: from EUR01-DB5-obe.outbound.protection.outlook.com (mail-db5eur01on0106.outbound.protection.outlook.com. [104.47.2.106]) by mx.google.com with ESMTPS id e196si3650532ita.89.2017.02.14.10.40.24 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 14 Feb 2017 10:40:24 -0800 (PST) From: Dmitry Safonov Subject: [PATCHv5 0/5] Fix compatible mmap() return pointer over 4Gb Date: Tue, 14 Feb 2017 21:36:16 +0300 Message-ID: <20170214183621.2537-1-dsafonov@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: 0x7f454c46@gmail.com, Dmitry Safonov , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Andy Lutomirski , Borislav Petkov , x86@kernel.org, linux-mm@kvack.org, Cyrill Gorcunov , Shuah Khan , linux-kselftest@vger.kernel.org There are a couple of fixes related to x86 mmap(): o 1-2 are just preparation to introduce new mmap bases o 3 fixes 32-bit syscall returning address over 4Gb in applications, launched from 64-bit binaries. This is done by introducing new bases: mmap_compat_base and mmap_compat_legacy_base. Those bases are separated from 64-bit ones, which allows to use mmap base according to bitness of the syscall. Which makes the behavior of 32-bit syscalls the same independently of launched binary's bitness (the same for 64-bit syscalls). It also makes possible to allocate with 64-bit mmap() address higher than 4Gb in compat ELFs - that may be used when 4Gb is not enough or with MAP_FIXED for hiding that mapping from 32-bit address space. o 4 fixes behavior of MAP_32BIT - at this moment it's related to the bitness of executed binary, not of the syscall. o 5 is a selftest to check that 32-bit mmap() does return 32-bit pointer. Changes since v4 (Thomas's review): - rewrote changelogs (so they should be readable by humans also) - made code simpler (fighting to ifdef horror, etc) Changes since v3: - fixed usage of 64-bit random mask for 32-bit mm->mmap_compat_base, during introducing mmap_compat{_legacy,}_base Changes since v2: - don't distinguish native and compat tasks by TIF_ADDR32, introduced mmap_compat{_legacy,}_base which allows to treat them the same - fixed kbuild errors Changes since v1: - Recalculate mmap_base instead of using max possible virtual address for compat/native syscall. That will make policy for allocation the same in 32-bit binaries and in 32-bit syscalls in 64-bit binaries. I need this because sys_mmap() in restored 32-bit process shouldn't hit the stack area. - Fixed mmap() with MAP_32BIT flag in the same usecases - used in_compat_syscall() helper rather TS_COMPAT check (Andy noticed) - introduced find_top() helper as suggested by Andy to simplify code - fixed test error-handeling: it checked the result of sys_mmap() with MMAP_FAILED, which is not correct, as it calls raw syscall - now checks return value to be aligned to PAGE_SIZE. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Andy Lutomirski Cc: Borislav Petkov Cc: x86@kernel.org Cc: linux-mm@kvack.org Cc: Cyrill Gorcunov Dmitry Safonov (5): x86/mm: introduce arch_rnd() to compute 32/64 mmap rnd x86/mm: add task_size parameter to mmap_base() x86/mm: introduce mmap_compat_base for 32-bit mmap() x86/mm: check in_compat_syscall() instead TIF_ADDR32 for mmap(MAP_32BIT) selftests/x86: add test for 32-bit mmap() return addr arch/Kconfig | 7 + arch/x86/Kconfig | 1 + arch/x86/include/asm/elf.h | 27 ++-- arch/x86/include/asm/processor.h | 4 +- arch/x86/kernel/sys_x86_64.c | 27 +++- arch/x86/mm/mmap.c | 109 ++++++++----- include/linux/mm_types.h | 5 + tools/testing/selftests/x86/Makefile | 2 +- tools/testing/selftests/x86/test_compat_mmap.c | 208 +++++++++++++++++++++++++ 9 files changed, 332 insertions(+), 58 deletions(-) create mode 100644 tools/testing/selftests/x86/test_compat_mmap.c -- 2.11.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org