From patchwork Wed Dec 23 15:57:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Chang S. Bae" X-Patchwork-Id: 11988605 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=-13.9 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNWANTED_LANGUAGE_BODY, URIBL_BLOCKED,USER_AGENT_GIT 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 D9747C4332D for ; Wed, 23 Dec 2020 16:03:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B1B1522D57 for ; Wed, 23 Dec 2020 16:03:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729168AbgLWQDe (ORCPT ); Wed, 23 Dec 2020 11:03:34 -0500 Received: from mga01.intel.com ([192.55.52.88]:1646 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728357AbgLWQDe (ORCPT ); Wed, 23 Dec 2020 11:03:34 -0500 IronPort-SDR: SBWieVz2UQbmgg+b6Sw7Xh2JzxAyWfRXsk8gVvVJNnO3SkdD6ImMUIAPLwk0olmGKrfVdwmMLl 4nbttDQa/rzA== X-IronPort-AV: E=McAfee;i="6000,8403,9844"; a="194483203" X-IronPort-AV: E=Sophos;i="5.78,441,1599548400"; d="scan'208";a="194483203" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Dec 2020 08:01:41 -0800 IronPort-SDR: anDQiVEKwCrnIDvgof9zLBKPiorNnVrSjbdjdkGuI2f56qVWlsbc4pEXOuJJEJZmWJl0GeJQcv qOaHpdGLVCEg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.78,441,1599548400"; d="scan'208";a="458028047" Received: from chang-linux-3.sc.intel.com ([172.25.66.175]) by fmsmga001.fm.intel.com with ESMTP; 23 Dec 2020 08:01:41 -0800 From: "Chang S. Bae" To: bp@suse.de, luto@kernel.org, tglx@linutronix.de, mingo@kernel.org, x86@kernel.org Cc: len.brown@intel.com, dave.hansen@intel.com, jing2.liu@intel.com, ravi.v.shankar@intel.com, linux-kernel@vger.kernel.org, chang.seok.bae@intel.com, linux-kselftest@vger.kernel.org Subject: [PATCH v3 19/21] selftest/x86/amx: Include test cases for the AMX state management Date: Wed, 23 Dec 2020 07:57:15 -0800 Message-Id: <20201223155717.19556-20-chang.seok.bae@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201223155717.19556-1-chang.seok.bae@intel.com> References: <20201223155717.19556-1-chang.seok.bae@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org This selftest exercises the kernel's behavior not to inherit AMX state and the ability to switch the context by verifying that they retain unique data between multiple threads. Also, ptrace() is used to insert AMX state into existing threads -- both before and after the existing thread has initialized its AMX state. Collect the test cases of validating those operations together, as they share some common setup for the AMX state. These test cases do not depend on AMX compiler support, as they employ user-space-XSAVE directly to access AMX state. Signed-off-by: Chang S. Bae Reviewed-by: Len Brown Cc: x86@kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-kselftest@vger.kernel.org --- Changes from v2: * Updated the test messages and the changelog as tile data is not inherited to a child anymore. * Removed bytecode for the instructions already supported by binutils. * Changed to check the XSAVE availability in a reliable way. Changes from v1: * Removed signal testing code --- tools/testing/selftests/x86/Makefile | 2 +- tools/testing/selftests/x86/amx.c | 677 +++++++++++++++++++++++++++ 2 files changed, 678 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/x86/amx.c diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile index 6703c7906b71..8408bbde788f 100644 --- a/tools/testing/selftests/x86/Makefile +++ b/tools/testing/selftests/x86/Makefile @@ -17,7 +17,7 @@ TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt test_mremap 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 +TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip syscall_numbering amx # 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/amx.c b/tools/testing/selftests/x86/amx.c new file mode 100644 index 000000000000..f4ecdfd27ae9 --- /dev/null +++ b/tools/testing/selftests/x86/amx.c @@ -0,0 +1,677 @@ +// SPDX-License-Identifier: GPL-2.0 + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#ifndef __x86_64__ +# error This test is 64-bit only +#endif + +typedef uint8_t u8; +typedef uint16_t u16; +typedef uint32_t u32; +typedef uint64_t u64; + +#define PAGE_SIZE (1 << 12) + +#define NUM_TILES 8 +#define TILE_SIZE 1024 +#define XSAVE_SIZE ((NUM_TILES * TILE_SIZE) + PAGE_SIZE) + +struct xsave_data { + u8 area[XSAVE_SIZE]; +} __attribute__((aligned(64))); + +/* Tile configuration associated: */ +#define MAX_TILES 16 +#define RESERVED_BYTES 14 + +struct tile_config { + u8 palette_id; + u8 start_row; + u8 reserved[RESERVED_BYTES]; + u16 colsb[MAX_TILES]; + u8 rows[MAX_TILES]; +}; + +struct tile_data { + u8 data[NUM_TILES * TILE_SIZE]; +}; + +static inline u64 __xgetbv(u32 index) +{ + u32 eax, edx; + + asm volatile("xgetbv;" + : "=a" (eax), "=d" (edx) + : "c" (index)); + return eax + ((u64)edx << 32); +} + +static inline void __cpuid(u32 *eax, u32 *ebx, u32 *ecx, u32 *edx) +{ + asm volatile("cpuid;" + : "=a" (*eax), "=b" (*ebx), "=c" (*ecx), "=d" (*edx) + : "0" (*eax), "2" (*ecx)); +} + +/* Load tile configuration */ +static inline void __ldtilecfg(void *cfg) +{ + asm volatile(".byte 0xc4,0xe2,0x78,0x49,0x00" + : : "a"(cfg)); +} + +/* Load tile data to %tmm0 register only */ +static inline void __tileloadd(void *tile) +{ + asm volatile(".byte 0xc4,0xe2,0x7b,0x4b,0x04,0x10" + : : "a"(tile), "d"(0)); +} + +/* Save extended states */ +static inline void __xsave(void *buffer, u32 lo, u32 hi) +{ + asm volatile("xsave (%%rdi)" + : : "D" (buffer), "a" (lo), "d" (hi) + : "memory"); +} + +/* Restore extended states */ +static inline void __xrstor(void *buffer, u32 lo, u32 hi) +{ + asm volatile("xrstor (%%rdi)" + : : "D" (buffer), "a" (lo), "d" (hi)); +} + +/* Release tile states to init values */ +static inline void __tilerelease(void) +{ + asm volatile(".byte 0xc4, 0xe2, 0x78, 0x49, 0xc0" ::); +} + +static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *), + int flags) +{ + struct sigaction sa; + + memset(&sa, 0, sizeof(sa)); + sa.sa_sigaction = handler; + sa.sa_flags = SA_SIGINFO | flags; + sigemptyset(&sa.sa_mask); + if (sigaction(sig, &sa, 0)) + err(1, "sigaction"); +} + +static void clearhandler(int sig) +{ + struct sigaction sa; + + memset(&sa, 0, sizeof(sa)); + sa.sa_handler = SIG_DFL; + sigemptyset(&sa.sa_mask); + if (sigaction(sig, &sa, 0)) + err(1, "sigaction"); +} + +/* Hardware info check: */ + +static jmp_buf jmpbuf; +static bool xsave_disabled; + +static void handle_sigill(int sig, siginfo_t *si, void *ctx_void) +{ + xsave_disabled = true; + siglongjmp(jmpbuf, 1); +} + +#define XFEATURE_XTILE_CFG 17 +#define XFEATURE_XTILE_DATA 18 +#define XFEATURE_MASK_XTILE ((1 << XFEATURE_XTILE_DATA) | \ + (1 << XFEATURE_XTILE_CFG)) + +static inline bool check_xsave_supports_xtile(void) +{ + bool supported = false; + + sethandler(SIGILL, handle_sigill, 0); + + if (!sigsetjmp(jmpbuf, 1)) + supported = __xgetbv(0) & XFEATURE_MASK_XTILE; + + clearhandler(SIGILL); + return supported; +} + +struct xtile_hwinfo { + struct { + u16 bytes_per_tile; + u16 bytes_per_row; + u16 max_names; + u16 max_rows; + } spec; + + struct { + u32 offset; + u32 size; + } xsave; +}; + +static struct xtile_hwinfo xtile; + +static bool __enum_xtile_config(void) +{ + u32 eax, ebx, ecx, edx; + u16 bytes_per_tile; + bool valid = false; + +#define TILE_CPUID 0x1d +#define TILE_PALETTE_CPUID_SUBLEAVE 0x1 + + eax = TILE_CPUID; + ecx = TILE_PALETTE_CPUID_SUBLEAVE; + + __cpuid(&eax, &ebx, &ecx, &edx); + if (!eax || !ebx || !ecx) + return valid; + + xtile.spec.max_names = ebx >> 16; + if (xtile.spec.max_names < NUM_TILES) + return valid; + + bytes_per_tile = eax >> 16; + if (bytes_per_tile < TILE_SIZE) + return valid; + + xtile.spec.bytes_per_row = ebx; + xtile.spec.max_rows = ecx; + valid = true; + + return valid; +} + +static bool __enum_xsave_tile(void) +{ + u32 eax, ebx, ecx, edx; + bool valid = false; + +#define XSTATE_CPUID 0xd +#define XSTATE_USER_STATE_SUBLEAVE 0x0 + + eax = XSTATE_CPUID; + ecx = XFEATURE_XTILE_DATA; + + __cpuid(&eax, &ebx, &ecx, &edx); + if (!eax || !ebx) + return valid; + + xtile.xsave.offset = ebx; + xtile.xsave.size = eax; + valid = true; + + return valid; +} + +static bool __check_xsave_size(void) +{ + u32 eax, ebx, ecx, edx; + bool valid = false; + + eax = XSTATE_CPUID; + ecx = XSTATE_USER_STATE_SUBLEAVE; + + __cpuid(&eax, &ebx, &ecx, &edx); + if (ebx && ebx <= XSAVE_SIZE) + valid = true; + + return valid; +} + +/* + * Check the hardware-provided tile state info and cross-check it with the + * hard-coded values: XSAVE_SIZE, NUM_TILES, and TILE_SIZE. + */ +static int check_xtile_hwinfo(void) +{ + bool success = false; + + if (!__check_xsave_size()) + return success; + + if (!__enum_xsave_tile()) + return success; + + if (!__enum_xtile_config()) + return success; + + if (sizeof(struct tile_data) >= xtile.xsave.size) + success = true; + + return success; +} + +/* The helpers for managing XSAVE buffer and tile states: */ + +/* Use the uncompacted format without 'init optimization' */ +static void save_xdata(void *data) +{ + __xsave(data, -1, -1); +} + +static void restore_xdata(void *data) +{ + __xrstor(data, -1, -1); +} + +static inline u64 __get_xsave_xstate_bv(void *data) +{ +#define XSAVE_HDR_OFFSET 512 + return *(u64 *)(data + XSAVE_HDR_OFFSET); +} + +static void set_tilecfg(struct tile_config *cfg) +{ + int i; + + memset(cfg, 0, sizeof(*cfg)); + /* The first implementation has one significant palette with id 1 */ + cfg->palette_id = 1; + for (i = 0; i < xtile.spec.max_names; i++) { + cfg->colsb[i] = xtile.spec.bytes_per_row; + cfg->rows[i] = xtile.spec.max_rows; + } +} + +static void load_tilecfg(struct tile_config *cfg) +{ + __ldtilecfg(cfg); +} + +static void make_tiles(void *tiles) +{ + u32 iterations = xtile.xsave.size / sizeof(u32); + static u32 value = 1; + u32 *ptr = tiles; + int i; + + for (i = 0, ptr = tiles; i < iterations; i++, ptr++) + *ptr = value; + value++; +} + +/* + * Initialize the XSAVE buffer: + * + * Make sure tile configuration loaded already. Load limited tile data (%tmm0 only) + * and save all the states. XSAVE buffer is ready to complete tile data. + */ +static void init_xdata(void *data) +{ + struct tile_data tiles; + + make_tiles(&tiles); + __tileloadd(&tiles); + __xsave(data, -1, -1); +} + +static inline void *__get_xsave_tile_data_addr(void *data) +{ + return data + xtile.xsave.offset; +} + +static void copy_tiles_to_xdata(void *xdata, void *tiles) +{ + void *dst = __get_xsave_tile_data_addr(xdata); + + memcpy(dst, tiles, xtile.xsave.size); +} + +static int compare_xdata_tiles(void *xdata, void *tiles) +{ + void *tile_data = __get_xsave_tile_data_addr(xdata); + + if (memcmp(tile_data, tiles, xtile.xsave.size)) + return 1; + + return 0; +} + +static int nerrs, errs; + +/* Testing tile data inheritance */ + +static void test_tile_data_inheritance(void) +{ + struct xsave_data xdata; + struct tile_data tiles; + struct tile_config cfg; + pid_t child; + int status; + + set_tilecfg(&cfg); + load_tilecfg(&cfg); + init_xdata(&xdata); + + make_tiles(&tiles); + copy_tiles_to_xdata(&xdata, &tiles); + restore_xdata(&xdata); + + errs = 0; + + child = fork(); + if (child < 0) + err(1, "fork"); + + if (child == 0) { + memset(&xdata, 0, sizeof(xdata)); + save_xdata(&xdata); + if (compare_xdata_tiles(&xdata, &tiles)) { + printf("[OK]\tchild didn't inherit tile data at fork()\n"); + } else { + printf("[FAIL]\tchild inherited tile data at fork()\n"); + nerrs++; + } + _exit(0); + } + wait(&status); +} + +static void test_fork(void) +{ + pid_t child; + int status; + + child = fork(); + if (child < 0) + err(1, "fork"); + + if (child == 0) { + test_tile_data_inheritance(); + _exit(0); + } + + wait(&status); +} + +/* Context switching test */ + +#define ITERATIONS 10 +#define NUM_THREADS 5 + +struct futex_info { + int current; + int next; + int *futex; +}; + +static inline void command_wait(struct futex_info *info, int value) +{ + do { + sched_yield(); + } while (syscall(SYS_futex, info->futex, FUTEX_WAIT, value, 0, 0, 0)); +} + +static inline void command_wake(struct futex_info *info, int value) +{ + do { + *info->futex = value; + while (!syscall(SYS_futex, info->futex, FUTEX_WAKE, 1, 0, 0, 0)) + sched_yield(); + } while (0); +} + +static inline int get_iterative_value(int id) +{ + return ((id << 1) & ~0x1); +} + +static inline int get_endpoint_value(int id) +{ + return ((id << 1) | 0x1); +} + +static void *check_tiles(void *info) +{ + struct futex_info *finfo = (struct futex_info *)info; + struct xsave_data xdata; + struct tile_data tiles; + struct tile_config cfg; + int i; + + set_tilecfg(&cfg); + load_tilecfg(&cfg); + init_xdata(&xdata); + + make_tiles(&tiles); + copy_tiles_to_xdata(&xdata, &tiles); + restore_xdata(&xdata); + + for (i = 0; i < ITERATIONS; i++) { + command_wait(finfo, get_iterative_value(finfo->current)); + + memset(&xdata, 0, sizeof(xdata)); + save_xdata(&xdata); + errs += compare_xdata_tiles(&xdata, &tiles); + + make_tiles(&tiles); + copy_tiles_to_xdata(&xdata, &tiles); + restore_xdata(&xdata); + + command_wake(finfo, get_iterative_value(finfo->next)); + } + + command_wait(finfo, get_endpoint_value(finfo->current)); + __tilerelease(); + return NULL; +} + +static int create_children(int num, struct futex_info *finfo) +{ + const int shm_id = shmget(IPC_PRIVATE, sizeof(int), IPC_CREAT | 0666); + int *futex = shmat(shm_id, NULL, 0); + pthread_t thread; + int i; + + for (i = 0; i < num; i++) { + finfo[i].futex = futex; + finfo[i].current = i + 1; + finfo[i].next = (i + 2) % (num + 1); + + if (pthread_create(&thread, NULL, check_tiles, &finfo[i])) { + err(1, "pthread_create"); + return 1; + } + } + return 0; +} + +static void test_context_switch(void) +{ + struct futex_info *finfo; + cpu_set_t cpuset; + int i; + + printf("[RUN]\t%u context switches of tile states in %d threads\n", + ITERATIONS * NUM_THREADS, NUM_THREADS); + + errs = 0; + + CPU_ZERO(&cpuset); + CPU_SET(0, &cpuset); + if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0) + err(1, "sched_setaffinity to CPU 0"); + + finfo = malloc(sizeof(*finfo) * NUM_THREADS); + + if (create_children(NUM_THREADS, finfo)) + return; + + for (i = 0; i < ITERATIONS; i++) { + command_wake(finfo, get_iterative_value(1)); + command_wait(finfo, get_iterative_value(0)); + } + + for (i = 1; i <= NUM_THREADS; i++) + command_wake(finfo, get_endpoint_value(i)); + + if (errs) { + printf("[FAIL]\t%u incorrect tile states\n", errs); + nerrs += errs; + return; + } + + printf("[OK]\tall tile states are correct\n"); +} + +/* Ptrace test */ + +static inline long get_tile_state(pid_t child, struct iovec *iov) +{ + return ptrace(PTRACE_GETREGSET, child, (u32)NT_X86_XSTATE, iov); +} + +static inline long set_tile_state(pid_t child, struct iovec *iov) +{ + return ptrace(PTRACE_SETREGSET, child, (u32)NT_X86_XSTATE, iov); +} + +static int write_tile_state(bool load_tile, pid_t child) +{ + struct xsave_data xdata; + struct tile_data tiles; + struct iovec iov; + + iov.iov_base = &xdata; + iov.iov_len = sizeof(xdata); + + if (get_tile_state(child, &iov)) + err(1, "PTRACE_GETREGSET"); + + make_tiles(&tiles); + copy_tiles_to_xdata(&xdata, &tiles); + if (set_tile_state(child, &iov)) + err(1, "PTRACE_SETREGSET"); + + memset(&xdata, 0, sizeof(xdata)); + if (get_tile_state(child, &iov)) + err(1, "PTRACE_GETREGSET"); + + if (!load_tile) + memset(&tiles, 0, sizeof(tiles)); + + return compare_xdata_tiles(&xdata, &tiles); +} + +static void test_tile_state_write(bool load_tile) +{ + pid_t child; + int status; + + child = fork(); + if (child < 0) + err(1, "fork"); + + if (child == 0) { + printf("[RUN]\tPtrace-induced tile state write, "); + printf("%s tile data loaded\n", load_tile ? "with" : "without"); + + if (ptrace(PTRACE_TRACEME, 0, NULL, NULL)) + err(1, "PTRACE_TRACEME"); + + if (load_tile) { + struct tile_config cfg; + struct tile_data tiles; + + set_tilecfg(&cfg); + load_tilecfg(&cfg); + make_tiles(&tiles); + /* Load only %tmm0 but inducing the #NM */ + __tileloadd(&tiles); + } + + raise(SIGTRAP); + _exit(0); + } + + do { + wait(&status); + } while (WSTOPSIG(status) != SIGTRAP); + + errs = write_tile_state(load_tile, child); + if (errs) { + nerrs++; + printf("[FAIL]\t%s write\n", load_tile ? "incorrect" : "unexpected"); + } else { + printf("[OK]\t%s write\n", load_tile ? "correct" : "no"); + } + + ptrace(PTRACE_DETACH, child, NULL, NULL); + wait(&status); +} + +static void test_ptrace(void) +{ + bool ptracee_loads_tiles; + + ptracee_loads_tiles = true; + test_tile_state_write(ptracee_loads_tiles); + + ptracee_loads_tiles = false; + test_tile_state_write(ptracee_loads_tiles); +} + +int main(void) +{ + /* Check hardware availability at first */ + + if (!check_xsave_supports_xtile()) { + if (xsave_disabled) + printf("XSAVE disabled.\n"); + else + printf("Tile data not available.\n"); + return 0; + } + + if (!check_xtile_hwinfo()) { + printf("Available tile state size is insufficient to test.\n"); + return 0; + } + + nerrs = 0; + + test_fork(); + test_context_switch(); + test_ptrace(); + + return nerrs ? 1 : 0; +} From patchwork Wed Dec 23 15:57:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Chang S. Bae" X-Patchwork-Id: 11988603 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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 DEBC7C433E9 for ; Wed, 23 Dec 2020 16:02:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BBF0422202 for ; Wed, 23 Dec 2020 16:02:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728465AbgLWQCY (ORCPT ); Wed, 23 Dec 2020 11:02:24 -0500 Received: from mga03.intel.com ([134.134.136.65]:51477 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728421AbgLWQCX (ORCPT ); Wed, 23 Dec 2020 11:02:23 -0500 IronPort-SDR: t6n7CF+SbtZu1Il8qkPopvGUP5qkyTYu1Bxx+xUar4O0/hGpCHi2tj9cSuuJiHxTJNCacEIgRW iUqsS++SmHsg== X-IronPort-AV: E=McAfee;i="6000,8403,9844"; a="176130532" X-IronPort-AV: E=Sophos;i="5.78,441,1599548400"; d="scan'208";a="176130532" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Dec 2020 08:01:42 -0800 IronPort-SDR: NgGIVCZ9caVTBX6CI/hQAb3UKswkGndWj0MAsGfGCNhlBRlIwACEqCq1zNt0Wo2SS/5B5LuPZF tAgnQte2g6EQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.78,441,1599548400"; d="scan'208";a="458028061" Received: from chang-linux-3.sc.intel.com ([172.25.66.175]) by fmsmga001.fm.intel.com with ESMTP; 23 Dec 2020 08:01:41 -0800 From: "Chang S. Bae" To: bp@suse.de, luto@kernel.org, tglx@linutronix.de, mingo@kernel.org, x86@kernel.org Cc: len.brown@intel.com, dave.hansen@intel.com, jing2.liu@intel.com, ravi.v.shankar@intel.com, linux-kernel@vger.kernel.org, chang.seok.bae@intel.com, linux-kselftest@vger.kernel.org Subject: [PATCH v3 20/21] x86/fpu/xstate: Support dynamic user state in the signal handling path Date: Wed, 23 Dec 2020 07:57:16 -0800 Message-Id: <20201223155717.19556-21-chang.seok.bae@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201223155717.19556-1-chang.seok.bae@intel.com> References: <20201223155717.19556-1-chang.seok.bae@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Entering a signal handler, the kernel saves the XSAVE buffer. The dynamic user state is better to be saved only when used. fpu->state_mask can help to exclude unused states. Returning from a signal handler, XRSTOR re-initializes the excluded state components. Add a test case to verify in the signal handler that the signal frame excludes AMX data when the signaled thread has initialized AMX state. No functional change until the kernel supports the dynamic user states. Signed-off-by: Chang S. Bae Reviewed-by: Len Brown Cc: x86@kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-kselftest@vger.kernel.org --- Changes from v1: * Made it revertible (moved close to the end of the series). * Included the test case. --- arch/x86/include/asm/fpu/internal.h | 2 +- tools/testing/selftests/x86/amx.c | 66 +++++++++++++++++++++++++++++ 2 files changed, 67 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 5eba9a466249..202874bb79da 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -369,7 +369,7 @@ static inline void copy_kernel_to_xregs(struct xregs_state *xstate, u64 mask) */ static inline int copy_xregs_to_user(struct xregs_state __user *buf) { - u64 mask = xfeatures_mask_user(); + u64 mask = current->thread.fpu.state_mask; u32 lmask = mask; u32 hmask = mask >> 32; int err; diff --git a/tools/testing/selftests/x86/amx.c b/tools/testing/selftests/x86/amx.c index f4ecdfd27ae9..a7386b886532 100644 --- a/tools/testing/selftests/x86/amx.c +++ b/tools/testing/selftests/x86/amx.c @@ -650,6 +650,71 @@ static void test_ptrace(void) test_tile_state_write(ptracee_loads_tiles); } +/* Signal handling test */ + +static int sigtrapped; +struct tile_data sig_tiles, sighdl_tiles; + +static void handle_sigtrap(int sig, siginfo_t *info, void *ctx_void) +{ + ucontext_t *uctxt = (ucontext_t *)ctx_void; + struct xsave_data xdata; + struct tile_config cfg; + struct tile_data tiles; + u64 header; + + header = __get_xsave_xstate_bv((void *)uctxt->uc_mcontext.fpregs); + + if (header & (1 << XFEATURE_XTILE_DATA)) + printf("[FAIL]\ttile data was written in sigframe\n"); + else + printf("[OK]\ttile data was skipped in sigframe\n"); + + set_tilecfg(&cfg); + load_tilecfg(&cfg); + init_xdata(&xdata); + + make_tiles(&tiles); + copy_tiles_to_xdata(&xdata, &tiles); + restore_xdata(&xdata); + + save_xdata(&xdata); + if (compare_xdata_tiles(&xdata, &tiles)) + err(1, "tile load file"); + + printf("\tsignal handler: load tile data\n"); + + sigtrapped = sig; +} + +static void test_signal_handling(void) +{ + struct xsave_data xdata = { 0 }; + struct tile_data tiles = { 0 }; + + sethandler(SIGTRAP, handle_sigtrap, 0); + sigtrapped = 0; + + printf("[RUN]\tCheck tile state management in handling signal\n"); + + printf("\tbefore signal: initial tile data state\n"); + + raise(SIGTRAP); + + if (sigtrapped == 0) + err(1, "sigtrap"); + + save_xdata(&xdata); + if (compare_xdata_tiles(&xdata, &tiles)) { + printf("[FAIL]\ttile data was not loaded at sigreturn\n"); + nerrs++; + } else { + printf("[OK]\ttile data was re-initialized at sigreturn\n"); + } + + clearhandler(SIGTRAP); +} + int main(void) { /* Check hardware availability at first */ @@ -672,6 +737,7 @@ int main(void) test_fork(); test_context_switch(); test_ptrace(); + test_signal_handling(); return nerrs ? 1 : 0; }