From patchwork Thu Nov 19 23:32:56 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: 328742 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 AD968C64E75 for ; Thu, 19 Nov 2020 23:38:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 63D8A208FE for ; Thu, 19 Nov 2020 23:38:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725843AbgKSXhb (ORCPT ); Thu, 19 Nov 2020 18:37:31 -0500 Received: from mga09.intel.com ([134.134.136.24]:7299 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727136AbgKSXhH (ORCPT ); Thu, 19 Nov 2020 18:37:07 -0500 IronPort-SDR: oos1ALgB7mowvDkalLNG2aBpznIzot5iUnQbft+ZBHo58JKwUHWIHhm6Sh5ncdZ+laPf3uP+Yf K1+RYPiKwlGQ== X-IronPort-AV: E=McAfee;i="6000,8403,9810"; a="171552666" X-IronPort-AV: E=Sophos;i="5.78,354,1599548400"; d="scan'208";a="171552666" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Nov 2020 15:37:04 -0800 IronPort-SDR: rKqAXp2x/M9MbnVBsgDBH66SipKhyB7k8J35fj5bF8Fu+R5Hr4sYf/iznv5eL2t55aQwS/FNn9 QdELojc+ZOSw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.78,354,1599548400"; d="scan'208";a="431392255" Received: from chang-linux-3.sc.intel.com ([172.25.66.175]) by fmsmga001.fm.intel.com with ESMTP; 19 Nov 2020 15:37:03 -0800 From: "Chang S. Bae" To: tglx@linutronix.de, mingo@kernel.org, bp@suse.de, luto@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 v2 21/22] x86/fpu/xstate: Support dynamic user state in the signal handling path Date: Thu, 19 Nov 2020 15:32:56 -0800 Message-Id: <20201119233257.2939-22-chang.seok.bae@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201119233257.2939-1-chang.seok.bae@intel.com> References: <20201119233257.2939-1-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 area. 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 test case --- arch/x86/include/asm/fpu/internal.h | 2 +- tools/testing/selftests/x86/amx.c | 89 +++++++++++++++++++++++++++++ 2 files changed, 90 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index ede3f88bdc52..d8e56e96df49 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 dce3b298f043..bf766b22cf77 100644 --- a/tools/testing/selftests/x86/amx.c +++ b/tools/testing/selftests/x86/amx.c @@ -623,6 +623,94 @@ 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 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"); +} + +static void sighandler(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 }; + + clearhandler(SIGTRAP); + sethandler(SIGTRAP, sighandler, 1); + 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"); + } +} + int main(void) { /* Check hardware availability at first */ @@ -642,6 +730,7 @@ int main(void) test_fork(); test_context_switch(); test_ptrace(); + test_signal_handling(); return nerrs ? 1 : 0; }