From patchwork Mon Aug 15 04:18:00 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Kirill A. Shutemov" X-Patchwork-Id: 12943090 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 53645C25B0E for ; Mon, 15 Aug 2022 04:15:21 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B12898E0001; Mon, 15 Aug 2022 00:15:14 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A9D188E0006; Mon, 15 Aug 2022 00:15:14 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 89EF08E0005; Mon, 15 Aug 2022 00:15:14 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 7200D8E0001 for ; Mon, 15 Aug 2022 00:15:14 -0400 (EDT) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 4684640C66 for ; Mon, 15 Aug 2022 04:15:14 +0000 (UTC) X-FDA: 79800512148.01.490F7B8 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by imf20.hostedemail.com (Postfix) with ESMTP id 82ACD1C0083 for ; Mon, 15 Aug 2022 04:15:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1660536913; x=1692072913; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=3EjyBFdwK4uZ3bVM+MhvlpEXA4APOBBafZji25n6VHM=; b=hFMNPjBJ5NYZlHJ60TdpFvPEY/We/qu2byIozTKRLxV+q99GFV51g2nq 3F/+4vKwdjceHyD3xxfqZnMj9u1olVuBtXNkr1V3/eE/NCj0lXWYTCVvG AwkZksrpebRwm97wwPmP9muJuMeL04MTdDO2zJYQZIRF7z4BgJmkdyuHc R9fWlJBx6iGj8ePgI+ue/8+EAPDg+HXcnC+WJ0a9/+t3z6tOrMasDtcBS j6fLhMcjW5JkZ3sV2xx63AV3QU2JcE1M8s2zeXlRpWFCDLGQXBRjO5cHO MEP+Q63L6G22YYWc4DLwoqGGfatFFB2YMQHLPT0kjA6M1rYAEl2Lvnlak Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10439"; a="292682701" X-IronPort-AV: E=Sophos;i="5.93,237,1654585200"; d="scan'208";a="292682701" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Aug 2022 21:15:11 -0700 X-IronPort-AV: E=Sophos;i="5.93,237,1654585200"; d="scan'208";a="674717535" Received: from dmalka-mobl.ger.corp.intel.com (HELO box.shutemov.name) ([10.249.42.26]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Aug 2022 21:15:07 -0700 Received: by box.shutemov.name (Postfix, from userid 1000) id 7C3F5104A6D; Mon, 15 Aug 2022 07:18:04 +0300 (+03) From: "Kirill A. Shutemov" To: Dave Hansen , Andy Lutomirski , Peter Zijlstra Cc: x86@kernel.org, Kostya Serebryany , Andrey Ryabinin , Andrey Konovalov , Alexander Potapenko , Taras Madan , Dmitry Vyukov , "H . J . Lu" , Andi Kleen , Rick Edgecombe , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Weihong Zhang , "Kirill A . Shutemov" Subject: [PATCHv6 08/11] selftests/x86/lam: Add malloc and tag-bits test cases for linear-address masking Date: Mon, 15 Aug 2022 07:18:00 +0300 Message-Id: <20220815041803.17954-9-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220815041803.17954-1-kirill.shutemov@linux.intel.com> References: <20220815041803.17954-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1660536913; a=rsa-sha256; cv=none; b=NiziNB65WBw1hT1IyX0gXVufQCsn9eW9LSNdBrfWkvEh43pR5GqvyAhY61qH0ae6zNT12T L9MYSRRQiY7K5MlhLP7SQUrrpp5PUQA/1hRbFxkDOkPtXmT/zeJiUjYeufkLaZgHW6T3g9 AtGSMX0irijC7zD9soY7j0CL5+v7++8= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1660536913; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Z4uz4IofWFydTuyzs8/tPvTjAgB+dcvop3gbaqRi21E=; b=YgpdBPbcxBfE5qJJavErjRUxz0mnu3piLcAY6bbzHkLpZjuBCCoVaxElgUUhZCMBeyszkO l/hLUiS5mwkvnFsQF/DIGEErIIy22ZcbZI3Kp/DUZIiz9mqscnoAQD7uBGrKrCWKEswgKz boPbSI6L1pwCkph/M1gcPbK0bKNm1Aw= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=hFMNPjBJ; spf=none (imf20.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 134.134.136.24) smtp.mailfrom=kirill.shutemov@linux.intel.com; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none) X-Stat-Signature: bwicccj4ipnbgmgis3hgqa5bksunw4yz X-Rspamd-Queue-Id: 82ACD1C0083 Authentication-Results: imf20.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=hFMNPjBJ; spf=none (imf20.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 134.134.136.24) smtp.mailfrom=kirill.shutemov@linux.intel.com; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none) X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1660536913-28469 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Weihong Zhang LAM is supported only in 64-bit mode and applies only addresses used for data accesses. In 64-bit mode, linear address have 64 bits. LAM is applied to 64-bit linear address and allow software to use high bits for metadata. LAM supports configurations that differ regarding which pointer bits are masked and can be used for metadata. LAM includes following mode: - LAM_U57, pointer bits in positions 62:57 are masked (LAM width 6), allows bits 62:57 of a user pointer to be used as metadata. There are two arch_prctls: ARCH_ENABLE_TAGGED_ADDR: enable LAM mode, mask high bits of a user pointer. ARCH_GET_UNTAG_MASK: get current untagged mask. ARCH_GET_MAX_TAG_BITS: the maximum tag bits user can request. zero if LAM is not supported. The LAM mode is for pre-process, a process has only one chance to set LAM mode. But there is no API to disable LAM mode. So all of test cases are run under child process. Functions of this test: MALLOC - LAM_U57 masks bits 57:62 of a user pointer. Process on user space can dereference such pointers. - Disable LAM, dereference a pointer with metadata above 48 bit or 57 bit lead to trigger SIGSEGV. TAG_BITS - Max tag bits of LAM_U57 is 6. Signed-off-by: Weihong Zhang Signed-off-by: Kirill A. Shutemov --- tools/testing/selftests/x86/Makefile | 2 +- tools/testing/selftests/x86/lam.c | 317 +++++++++++++++++++++++++++ 2 files changed, 318 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/x86/lam.c diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile index 0388c4d60af0..c1a16a9d4f2f 100644 --- a/tools/testing/selftests/x86/Makefile +++ b/tools/testing/selftests/x86/Makefile @@ -18,7 +18,7 @@ TARGETS_C_32BIT_ONLY := entry_from_vm86 test_syscall_vdso unwind_vdso \ test_FCMOV test_FCOMI test_FISTTP \ vdso_restorer TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip syscall_numbering \ - corrupt_xstate_header amx + corrupt_xstate_header amx lam # Some selftests require 32bit support enabled also on 64bit systems TARGETS_C_32BIT_NEEDED := ldt_gdt ptrace_syscall diff --git a/tools/testing/selftests/x86/lam.c b/tools/testing/selftests/x86/lam.c new file mode 100644 index 000000000000..4c6c6dbf7db6 --- /dev/null +++ b/tools/testing/selftests/x86/lam.c @@ -0,0 +1,317 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "../kselftest.h" + +#ifndef __x86_64__ +# error This test is 64-bit only +#endif + +/* LAM modes, these definitions were copied from kernel code */ +#define LAM_NONE 0 +#define LAM_U57_BITS 6 +/* arch prctl for LAM */ +#define ARCH_GET_UNTAG_MASK 0x4001 +#define ARCH_ENABLE_TAGGED_ADDR 0x4002 +#define ARCH_GET_MAX_TAG_BITS 0x4003 + +/* Specified test function bits */ +#define FUNC_MALLOC 0x1 +#define FUNC_BITS 0x2 + +#define TEST_MASK 0x3 + +#define MALLOC_LEN 32 + +struct testcases { + unsigned int later; + int expected; /* 2: SIGSEGV Error; 1: other errors */ + unsigned long lam; + uint64_t addr; + int (*test_func)(struct testcases *test); + const char *msg; +}; + +int tests_cnt; +jmp_buf segv_env; + +static void segv_handler(int sig) +{ + ksft_print_msg("Get segmentation fault(%d).", sig); + siglongjmp(segv_env, 1); +} + +static inline int cpu_has_lam(void) +{ + unsigned int cpuinfo[4]; + + __cpuid_count(0x7, 1, cpuinfo[0], cpuinfo[1], cpuinfo[2], cpuinfo[3]); + + return (cpuinfo[0] & (1 << 26)); +} + +/* + * Set tagged address and read back untag mask. + * check if the untagged mask is expected. + */ +static int set_lam(unsigned long lam) +{ + int ret = 0; + uint64_t ptr = 0; + + if (lam != LAM_U57_BITS && lam != LAM_NONE) + return -1; + + /* Skip check return */ + syscall(SYS_arch_prctl, ARCH_ENABLE_TAGGED_ADDR, lam); + + /* Get untagged mask */ + syscall(SYS_arch_prctl, ARCH_GET_UNTAG_MASK, &ptr); + + /* Check mask returned is expected */ + if (lam == LAM_U57_BITS) + ret = (ptr != ~(0x3fULL << 57)); + else if (lam == LAM_NONE) + ret = (ptr != -1ULL); + + return ret; +} + +static unsigned long get_default_tag_bits(void) +{ + pid_t pid; + int lam = LAM_NONE; + int ret = 0; + + pid = fork(); + if (pid < 0) { + perror("Fork failed."); + ret = 1; + } else if (pid == 0) { + /* Set LAM mode in parent process */ + if (set_lam(LAM_U57_BITS) == 0) + lam = LAM_U57_BITS; + else + lam = LAM_NONE; + exit(lam); + } else { + wait(&ret); + lam = WEXITSTATUS(ret); + } + + return lam; +} + +/* According to LAM mode, set metadata in high bits */ +static uint64_t get_metadata(uint64_t src, unsigned long lam) +{ + uint64_t metadata; + + srand(time(NULL)); + /* Get a random value as metadata */ + metadata = rand(); + + switch (lam) { + case LAM_U57_BITS: /* Set metadata in bits 62:57 */ + metadata = (src & ~(0x3fULL << 57)) | ((metadata & 0x3f) << 57); + break; + default: + metadata = src; + break; + } + + return metadata; +} + +/* + * Set metadata in user pointer, compare new pointer with original pointer. + * both pointers should point to the same address. + */ +static int handle_lam_test(void *src, unsigned int lam) +{ + char *ptr; + + strcpy((char *)src, "USER POINTER"); + + ptr = (char *)get_metadata((uint64_t)src, lam); + if (src == ptr) + return 0; + + /* Copy a string into the pointer with metadata */ + strcpy((char *)ptr, "METADATA POINTER"); + + return (!!strcmp((char *)src, (char *)ptr)); +} + + +int handle_max_bits(struct testcases *test) +{ + unsigned long exp_bits = get_default_tag_bits(); + unsigned long bits = 0; + + if (exp_bits != LAM_NONE) + exp_bits = LAM_U57_BITS; + + /* Get LAM max tag bits */ + if (syscall(SYS_arch_prctl, ARCH_GET_MAX_TAG_BITS, &bits) == -1) + return 1; + + return (exp_bits != bits); +} + +/* + * Test lam feature through dereference pointer get from malloc. + * @return 0: Pass test. 1: Get failure during test 2: Get SIGSEGV + */ +static int handle_malloc(struct testcases *test) +{ + char *ptr = NULL; + int ret = 0; + + if (test->later == 0 && test->lam != 0) + if (set_lam(test->lam) == -1) + return 1; + + ptr = (char *)malloc(MALLOC_LEN); + if (ptr == NULL) { + perror("malloc() failure\n"); + return 1; + } + + /* Set signal handler */ + if (sigsetjmp(segv_env, 1) == 0) { + signal(SIGSEGV, segv_handler); + ret = handle_lam_test(ptr, test->lam); + } else { + ret = 2; + } + + if (test->later != 0 && test->lam != 0) + if (set_lam(test->lam) == -1 && ret == 0) + ret = 1; + + free(ptr); + + return ret; +} + +static int fork_test(struct testcases *test) +{ + int ret, child_ret; + pid_t pid; + + pid = fork(); + if (pid < 0) { + perror("Fork failed."); + ret = 1; + } else if (pid == 0) { + ret = test->test_func(test); + exit(ret); + } else { + wait(&child_ret); + ret = WEXITSTATUS(child_ret); + } + + return ret; +} + +static void run_test(struct testcases *test, int count) +{ + int i, ret = 0; + + for (i = 0; i < count; i++) { + struct testcases *t = test + i; + + /* fork a process to run test case */ + ret = fork_test(t); + if (ret != 0) + ret = (t->expected == ret); + else + ret = !(t->expected); + + tests_cnt++; + ksft_test_result(ret, t->msg); + } +} + +static struct testcases malloc_cases[] = { + { + .later = 0, + .lam = LAM_U57_BITS, + .test_func = handle_malloc, + .msg = "MALLOC: LAM_U57. Dereferencing pointer with metadata\n", + }, + { + .later = 1, + .expected = 2, + .lam = LAM_U57_BITS, + .test_func = handle_malloc, + .msg = "MALLOC:[Negtive] Disable LAM. Dereferencing pointer with metadata.\n", + }, +}; + + +static struct testcases bits_cases[] = { + { + .test_func = handle_max_bits, + .msg = "BITS: Check default tag bits\n", + }, +}; + +static void cmd_help(void) +{ + printf("usage: lam [-h] [-t test list]\n"); + printf("\t-t test list: run tests specified in the test list, default:0x%x\n", TEST_MASK); + printf("\t\t0x1:malloc; 0x2:max_bits;\n"); + printf("\t-h: help\n"); +} + +int main(int argc, char **argv) +{ + int c = 0; + unsigned int tests = TEST_MASK; + + tests_cnt = 0; + + if (!cpu_has_lam()) { + ksft_print_msg("Unsupported LAM feature!\n"); + return -1; + } + + while ((c = getopt(argc, argv, "ht:")) != -1) { + switch (c) { + case 't': + tests = strtoul(optarg, NULL, 16); + if (!(tests & TEST_MASK)) { + ksft_print_msg("Invalid argument!\n"); + return -1; + } + break; + case 'h': + cmd_help(); + return 0; + default: + ksft_print_msg("Invalid argument\n"); + return -1; + } + } + + if (tests & FUNC_MALLOC) + run_test(malloc_cases, ARRAY_SIZE(malloc_cases)); + + if (tests & FUNC_BITS) + run_test(bits_cases, ARRAY_SIZE(bits_cases)); + + ksft_set_plan(tests_cnt); + + return ksft_exit_pass(); +}