From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f199.google.com (mail-ob0-f199.google.com [209.85.214.199]) by kanga.kvack.org (Postfix) with ESMTP id 310DE6B025E for ; Tue, 17 May 2016 08:15:17 -0400 (EDT) Received: by mail-ob0-f199.google.com with SMTP id w8so17761858obg.0 for ; Tue, 17 May 2016 05:15:17 -0700 (PDT) Received: from EUR01-HE1-obe.outbound.protection.outlook.com (mail-he1eur01on0117.outbound.protection.outlook.com. [104.47.0.117]) by mx.google.com with ESMTPS id dh8si1130744oec.66.2016.05.17.05.15.14 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 17 May 2016 05:15:14 -0700 (PDT) From: Dmitry Safonov Subject: [PATCHv9 2/2] selftest/x86: add mremap vdso test Date: Tue, 17 May 2016 15:13:52 +0300 Message-ID: <1463487232-4377-3-git-send-email-dsafonov@virtuozzo.com> In-Reply-To: <1463487232-4377-1-git-send-email-dsafonov@virtuozzo.com> References: <1463487232-4377-1-git-send-email-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, mingo@redhat.com Cc: luto@amacapital.net, tglx@linutronix.de, hpa@zytor.com, x86@kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org, 0x7f454c46@gmail.com, Dmitry Safonov , Shuah Khan , linux-kselftest@vger.kernel.org Should print on success: [root@localhost ~]# ./test_mremap_vdso_32 AT_SYSINFO_EHDR is 0xf773f000 [NOTE] Moving vDSO: [f773f000, f7740000] -> [a000000, a001000] [OK] Or segfault if landing was bad (before patches): [root@localhost ~]# ./test_mremap_vdso_32 AT_SYSINFO_EHDR is 0xf774f000 [NOTE] Moving vDSO: [f774f000, f7750000] -> [a000000, a001000] Segmentation fault (core dumped) Cc: Shuah Khan Cc: linux-kselftest@vger.kernel.org Suggested-by: Andy Lutomirski Signed-off-by: Dmitry Safonov Acked-by: Andy Lutomirski --- tools/testing/selftests/x86/Makefile | 2 +- tools/testing/selftests/x86/test_mremap_vdso.c | 99 ++++++++++++++++++++++++++ 2 files changed, 100 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/x86/test_mremap_vdso.c diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile index c73425de3cfe..a691cdeb1fef 100644 --- a/tools/testing/selftests/x86/Makefile +++ b/tools/testing/selftests/x86/Makefile @@ -5,7 +5,7 @@ include ../lib.mk .PHONY: all all_32 all_64 warn_32bit_failure clean TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt ptrace_syscall \ - check_initial_reg_state sigreturn ldt_gdt iopl + check_initial_reg_state sigreturn ldt_gdt iopl test_mremap_vdso TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault test_syscall_vdso unwind_vdso \ test_FCMOV test_FCOMI test_FISTTP \ vdso_restorer diff --git a/tools/testing/selftests/x86/test_mremap_vdso.c b/tools/testing/selftests/x86/test_mremap_vdso.c new file mode 100644 index 000000000000..831e2e0107d9 --- /dev/null +++ b/tools/testing/selftests/x86/test_mremap_vdso.c @@ -0,0 +1,99 @@ +/* + * 32-bit test to check vdso mremap. + * + * Copyright (c) 2016 Dmitry Safonov + * Suggested-by: Andrew Lutomirski + * + * This program is free software; you can redistribute it and/or modify + * it under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + */ +/* + * Can be built statically: + * gcc -Os -Wall -static -m32 test_mremap_vdso.c + */ +#define _GNU_SOURCE +#include +#include +#include +#include + +#include +#include +#include + +#define PAGE_SIZE 4096 + +static int try_to_remap(void *vdso_addr, unsigned long size) +{ + void *dest_addr, *new_addr; + + dest_addr = mmap(0, size, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); + if (dest_addr == MAP_FAILED) { + printf("[WARN]\tmmap failed (%d): %m\n", errno); + return 0; + } + + printf("[NOTE]\tMoving vDSO: [%p, %#lx] -> [%p, %#lx]\n", + vdso_addr, (unsigned long)vdso_addr + size, + dest_addr, (unsigned long)dest_addr + size); + fflush(stdout); + + new_addr = mremap(vdso_addr, size, size, + MREMAP_FIXED|MREMAP_MAYMOVE, dest_addr); + if ((unsigned long)new_addr == (unsigned long)-1) { + munmap(dest_addr, size); + if (errno == EINVAL) { + printf("[NOTE]\tvDSO partial move failed, will try with bigger size\n"); + return -1; /* retry with larger */ + } + printf("[FAIL]\tmremap failed (%d): %m\n", errno); + return 1; + } + + return 0; + +} + +int main(int argc, char **argv, char **envp) +{ + unsigned long auxval; + const char *ok_string = "[OK]\n"; + int ret = -1; + unsigned long vdso_size = PAGE_SIZE; + + auxval = getauxval(AT_SYSINFO_EHDR); + printf("\tAT_SYSINFO_EHDR is %#lx\n", auxval); + if (!auxval || auxval == -ENOENT) { + printf("[WARN]\tgetauxval failed\n"); + return 0; + } + + /* simpler than parsing ELF header */ + while (ret < 0) { + ret = try_to_remap((void *)auxval, vdso_size); + vdso_size += PAGE_SIZE; + } + + if (!ret) +#if defined(__i386__) + asm volatile ("int $0x80" : : + "a" (__NR_write), "b" (STDOUT_FILENO), + "c" (ok_string), "d" (strlen(ok_string))); + + asm volatile ("int $0x80" : : "a" (__NR_exit), "b" (!!ret)); +#else + asm volatile ("syscall" : : + "a" (__NR_write), "D" (STDOUT_FILENO), + "S" (ok_string), "d" (strlen(ok_string))); + + asm volatile ("syscall" : : "a" (__NR_exit), "D" (!!ret)); +#endif + + return 0; +} -- 2.8.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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