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=-16.7 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 6BD7EC43331 for ; Wed, 23 Dec 2020 16:03:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 48F1322202 for ; Wed, 23 Dec 2020 16:03:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728955AbgLWQC4 (ORCPT ); Wed, 23 Dec 2020 11:02:56 -0500 Received: from mga01.intel.com ([192.55.52.88]:1574 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728899AbgLWQCx (ORCPT ); Wed, 23 Dec 2020 11:02:53 -0500 IronPort-SDR: BwfgESa8TRUx14kZUHSKUAu+XyrpSb4UFRonUPwNiSPww+E5Dwx9ytCVNXLjbGC3+Ok5jUnAPG JC9JT5aA7gAA== X-IronPort-AV: E=McAfee;i="6000,8403,9844"; a="194483187" X-IronPort-AV: E=Sophos;i="5.78,441,1599548400"; d="scan'208";a="194483187" 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 08:01:40 -0800 IronPort-SDR: J7Rn1MsgdJh5mnJ5S9h2WjqaarqWpXluYoYUxITZDL79xGaslaLHPQE8Z0uDbOhuEHrbPM0Br4 i0eFIWp0MbLg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.78,441,1599548400"; d="scan'208";a="458027991" Received: from chang-linux-3.sc.intel.com ([172.25.66.175]) by fmsmga001.fm.intel.com with ESMTP; 23 Dec 2020 08:01:40 -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 v3 12/21] x86/fpu/xstate: Update xstate context copy function to support dynamic buffer Date: Wed, 23 Dec 2020 07:57:08 -0800 Message-Id: <20201223155717.19556-13-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-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. No functional change until the kernel supports dynamic user states. Signed-off-by: Chang S. Bae Reviewed-by: Len Brown Cc: x86@kernel.org Cc: linux-kernel@vger.kernel.org --- Changes from v2: * Updated the changelog with task->fpu removed. (Boris Petkov) --- arch/x86/kernel/fpu/xstate.c | 55 +++++++++++++++++++++++++++--------- 1 file changed, 41 insertions(+), 14 deletions(-) diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 6b863b2ca405..1d7d0cce6cc5 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -248,12 +248,14 @@ void fpstate_sanitize_xstate(struct fpu *fpu) if (!(xfeatures & XFEATURE_MASK_SSE)) memset(&fx->xmm_space[0], 0, 256); + /* Make sure 'xfeatures' to be a subset of fpu->state_mask */ + xfeatures = ((xfeatures_mask_user() & fpu->state_mask) & ~xfeatures); /* * First two features are FPU and SSE, which above we handled * in a special way already: */ feature_bit = 0x2; - xfeatures = (xfeatures_mask_user() & ~xfeatures) >> 2; + xfeatures >>= 0x2; /* * Update all the remaining memory layouts according to their @@ -262,12 +264,15 @@ void fpstate_sanitize_xstate(struct fpu *fpu) */ while (xfeatures) { if (xfeatures & 0x1) { - int offset = xstate_comp_offsets[feature_bit]; - int size = xstate_sizes[feature_bit]; - - memcpy((void *)xsave + offset, - (void *)&init_fpstate.xsave + offset, - size); + unsigned int offset = get_xstate_comp_offset(fpu, feature_bit); + unsigned int size = xstate_sizes[feature_bit]; + + if (get_init_fpstate_mask() & BIT_ULL(feature_bit)) + memcpy((void *)xsave + offset, + (void *)&init_fpstate.xsave + offset, + size); + else + memset((void *)xsave + offset, 0, size); } xfeatures >>= 1; @@ -1232,7 +1237,10 @@ 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); + if (offset <= get_init_fpstate_size()) + membuf_write(to, (void *)&init_fpstate.xsave + *last, offset - *last); + else + membuf_zero(to, offset - *last); *last = offset; } @@ -1240,7 +1248,10 @@ 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; } @@ -1292,12 +1303,22 @@ 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; /* - * Copy only in-use xstates: + * Copy only in-use xstate at first. If the feature is enabled, + * find the init value, whether stored in init_fpstate or simply + * zeros, and then copy them. */ - if ((header.xfeatures >> i) & 1) { - void *src = __raw_xsave_addr(fpu, i); - + if (header.xfeatures & mask) { + src = __raw_xsave_addr(fpu, i); + copy_part(&to, &last, xstate_offsets[i], + xstate_sizes[i], src); + } else if (xfeatures_mask_user() & mask) { + if (get_init_fpstate_mask() & mask) + src = (void *)&init_fpstate.xsave + last; + else + src = NULL; copy_part(&to, &last, xstate_offsets[i], xstate_sizes[i], src); } @@ -1331,6 +1352,9 @@ 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]; @@ -1388,6 +1412,9 @@ 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]; @@ -1470,7 +1497,7 @@ 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, i), xbuf + xstate_supervisor_only_offsets[i], xstate_sizes[i]); } -- 2.17.1