From mboxrd@z Thu Jan 1 00:00:00 1970 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 D4F41C433DB for ; Sun, 21 Feb 2021 19:08:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9A56464EBE for ; Sun, 21 Feb 2021 19:08:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231184AbhBUTHo (ORCPT ); Sun, 21 Feb 2021 14:07:44 -0500 Received: from mga09.intel.com ([134.134.136.24]:2102 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230489AbhBUTCt (ORCPT ); Sun, 21 Feb 2021 14:02:49 -0500 IronPort-SDR: v2K388FoOp+YwJCmpgVALKWDYeBYF9Vp+pUQJuMv0sLYceadl03YUaAbT5JH/yi/dZNANQIgEq GOz8xv7Xi2ig== X-IronPort-AV: E=McAfee;i="6000,8403,9902"; a="184382828" X-IronPort-AV: E=Sophos;i="5.81,195,1610438400"; d="scan'208";a="184382828" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Feb 2021 11:01:29 -0800 IronPort-SDR: IKM2npi+IW40bLIDIhUdRXe17q9KYc8lYKScauePByQSZlwTikVOShQP+gf/zYCuXo/kh3zBU6 igBt24Xj+6Wg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.81,195,1610438400"; d="scan'208";a="429792118" Received: from chang-linux-3.sc.intel.com ([172.25.66.175]) by FMSMGA003.fm.intel.com with ESMTP; 21 Feb 2021 11:01:27 -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 Subject: [PATCH v4 13/22] x86/fpu/xstate: Update the xstate context copy function to support dynamic states Date: Sun, 21 Feb 2021 10:56:28 -0800 Message-Id: <20210221185637.19281-14-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-kernel@vger.kernel.org ptrace() and signal return paths use xstate context copy functions. They allow callers to read (or write) xstate values in the target's buffer. With dynamic user states, a component's position in the buffer may vary and the initial value is not always stored in init_fpstate. Change the helpers to find a component's offset accordingly. When copying an initial value, explicitly check the init_fpstate coverage. If not found, reset the memory in the destination. Otherwise, copy values from init_fpstate. Signed-off-by: Chang S. Bae Reviewed-by: Len Brown Cc: x86@kernel.org Cc: linux-kernel@vger.kernel.org --- Changes from v3: * Cleaned up the code change with more comments. * Removed 'no functional change' in the changelog. (Borislav Petkov) Changes from v2: * Updated the changelog with task->fpu removed. (Borislav Petkov) --- arch/x86/kernel/fpu/xstate.c | 69 ++++++++++++++++++++++++++++-------- 1 file changed, 55 insertions(+), 14 deletions(-) diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 84b55f51bdb7..c57877df797d 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -301,7 +301,7 @@ void fpstate_sanitize_xstate(struct fpu *fpu) * in a special way already: */ feature_bit = 0x2; - xfeatures = (xfeatures_mask_user() & ~xfeatures) >> 2; + xfeatures = (xfeatures_mask_user() & fpu->state_mask & ~xfeatures) >> feature_bit; /* * Update all the remaining memory layouts according to their @@ -310,12 +310,19 @@ void fpstate_sanitize_xstate(struct fpu *fpu) */ while (xfeatures) { if (xfeatures & 0x1) { - int offset = xstate_comp_offsets[feature_bit]; + int offset = get_xstate_comp_offset(fpu->state_mask, feature_bit); int size = xstate_sizes[feature_bit]; - memcpy((void *)fx + offset, - (void *)&init_fpstate.xsave + offset, - size); + /* + * init_fpstate does not include the dynamic user states + * as having initial values with zeros. + */ + if (xfeatures_mask_user_dynamic & BIT_ULL(feature_bit)) + memset((void *)fx + offset, 0, size); + else + memcpy((void *)fx + offset, + (void *)&init_fpstate.xsave + offset, + size); } xfeatures >>= 1; @@ -1291,15 +1298,31 @@ static void fill_gap(struct membuf *to, unsigned *last, unsigned offset) { if (*last >= offset) return; - membuf_write(to, (void *)&init_fpstate.xsave + *last, offset - *last); + + /* + * Copy initial data. + * + * init_fpstate buffer has the minimum size as excluding the dynamic user + * states. But their initial values are zeros. + */ + if (offset <= get_xstate_config(XSTATE_MIN_SIZE)) + membuf_write(to, (void *)&init_fpstate.xsave + *last, offset - *last); + else + membuf_zero(to, offset - *last); *last = offset; } +/* + * @from: If NULL, copy zeros. + */ static void copy_part(struct membuf *to, unsigned *last, unsigned offset, unsigned size, void *from) { fill_gap(to, last, offset); - membuf_write(to, from, size); + if (from) + membuf_write(to, from, size); + else + membuf_zero(to, size); *last = offset + size; } @@ -1351,15 +1374,27 @@ void copy_xstate_to_kernel(struct membuf to, struct fpu *fpu) sizeof(header), &header); for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { + u64 mask = BIT_ULL(i); + void *src; + + if (!(xfeatures_mask_user() & mask)) + continue; + /* - * Copy only in-use xstates: + * Copy states if used. Otherwise, copy the initial data. */ - if ((header.xfeatures >> i) & 1) { - void *src = __raw_xsave_addr(fpu, i); - copy_part(&to, &last, xstate_offsets[i], - xstate_sizes[i], src); - } + if (header.xfeatures & mask) + src = __raw_xsave_addr(fpu, i); + else + /* + * init_fpstate buffer does not include the dynamic + * user state data as having initial values with zeros. + */ + src = (xfeatures_mask_user_dynamic & mask) ? + NULL : (void *)&init_fpstate.xsave + last; + + copy_part(&to, &last, xstate_offsets[i], xstate_sizes[i], src); } fill_gap(&to, &last, size); @@ -1392,6 +1427,9 @@ int copy_kernel_to_xstate(struct fpu *fpu, const void *kbuf) if (hdr.xfeatures & mask) { void *dst = __raw_xsave_addr(fpu, i); + if (!dst) + continue; + offset = xstate_offsets[i]; size = xstate_sizes[i]; @@ -1449,6 +1487,9 @@ int copy_user_to_xstate(struct fpu *fpu, const void __user *ubuf) if (hdr.xfeatures & mask) { void *dst = __raw_xsave_addr(fpu, i); + if (!dst) + continue; + offset = xstate_offsets[i]; size = xstate_sizes[i]; @@ -1529,7 +1570,7 @@ void copy_supervisor_to_kernel(struct fpu *fpu) continue; /* Move xfeature 'i' into its normal location */ - memmove(xbuf + xstate_comp_offsets[i], + memmove(xbuf + get_xstate_comp_offset(fpu->state_mask, i), xbuf + xstate_supervisor_only_offsets[i], xstate_sizes[i]); } -- 2.17.1