From patchwork Sun Feb 21 18:56:36 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Chang S. Bae" X-Patchwork-Id: 12097589 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=-16.8 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 17FDDC433E0 for ; Sun, 21 Feb 2021 19:03:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E2BDC64EDE for ; Sun, 21 Feb 2021 19:03:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231193AbhBUTDV (ORCPT ); Sun, 21 Feb 2021 14:03:21 -0500 Received: from mga07.intel.com ([134.134.136.100]:53159 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230494AbhBUTCy (ORCPT ); Sun, 21 Feb 2021 14:02:54 -0500 IronPort-SDR: Yl6MvMmXhr/R0ymCVEEEPv12ghG7K3Kx1XuHw/hSHt5RtBuaU4Px+eX3wL7Y61Tjq4X/zdJamy 83dxijdcCsWA== X-IronPort-AV: E=McAfee;i="6000,8403,9902"; a="248330336" X-IronPort-AV: E=Sophos;i="5.81,195,1610438400"; d="scan'208";a="248330336" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Feb 2021 11:01:29 -0800 IronPort-SDR: +SSKlxcFeCzaDrYZnsGUhFio2Qjl2wWWV8oSe2FjNHOdzQxyeLwcyhf2Sx/3Wc2lAWgPrSHZbs prsDzTOE/scw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.81,195,1610438400"; d="scan'208";a="429792146" Received: from chang-linux-3.sc.intel.com ([172.25.66.175]) by FMSMGA003.fm.intel.com with ESMTP; 21 Feb 2021 11:01:29 -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 v4 21/22] x86/fpu/xstate: Support dynamic user state in the signal handling path Date: Sun, 21 Feb 2021 10:56:36 -0800 Message-Id: <20210221185637.19281-22-chang.seok.bae@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210221185637.19281-1-chang.seok.bae@intel.com> References: <20210221185637.19281-1-chang.seok.bae@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Entering a signal handler, the kernel saves xstate in signal frame. 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. 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 v3: * Removed 'no functional changes' in the changelog. (Borislav Petkov) Changes from v1: * Made it revertable (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 c467312d38d8..090eb5bb277b 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -354,7 +354,7 @@ 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; }