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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E27AAC19F2C for ; Tue, 16 Aug 2022 06:18:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229976AbiHPGSB (ORCPT ); Tue, 16 Aug 2022 02:18:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45138 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229957AbiHPGRn (ORCPT ); Tue, 16 Aug 2022 02:17:43 -0400 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8CA92170D2E for ; Mon, 15 Aug 2022 17:07:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1660608444; x=1692144444; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Dm62JUBwIyAaLuk4bDQ0xZJ3mBhSTUqA23F0UfzoqnQ=; b=AMEFF4G/QIpJ3YMXbjJ0lX34EVPu5ut2MssRo9IFbiDdXFQX7TmwchGu lRaspzmeqigi8gGfBOlRs/fBdkf0foFBBvDzHBOEWE6K00iluqBPQcnNM sHUTqyb/uM37hWTeGFq9UaDkVeJGrLrZ98QRoPPYZorI1QGU2Rr0gHpDH urBw/W2uPx3XeH9sLAGo42/vKWFFk3DdHJcPlUOfvXxNV959ihXG8R0hJ zY3+67/rXMtUmLV/ljprGMX5e2BAOiywENbvikf1oYMpQB0PYOEZGj/g2 r3tpWMVD2OKd2iJsgW4yKeH1ro7H3rSpXZ8xfNMauy0koWwFFHbGVyiZz g==; X-IronPort-AV: E=McAfee;i="6400,9594,10440"; a="271857089" X-IronPort-AV: E=Sophos;i="5.93,239,1654585200"; d="scan'208";a="271857089" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2022 17:07:23 -0700 X-IronPort-AV: E=Sophos;i="5.93,239,1654585200"; d="scan'208";a="696145142" Received: from mpetrica-mobl.ger.corp.intel.com (HELO box.shutemov.name) ([10.252.38.195]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2022 17:07:19 -0700 Received: by box.shutemov.name (Postfix, from userid 1000) id CDA15104A4B; Tue, 16 Aug 2022 03:10:22 +0300 (+03) From: "Kirill A. Shutemov" To: kirill.shutemov@linux.intel.com Cc: ak@linux.intel.com, andreyknvl@gmail.com, dave.hansen@linux.intel.com, dvyukov@google.com, glider@google.com, hjl.tools@gmail.com, kcc@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, luto@kernel.org, peterz@infradead.org, rick.p.edgecombe@intel.com, ryabinin.a.a@gmail.com, tarasmadan@google.com, x86@kernel.org Subject: [PATCHv6.1 06/11] x86/mm: Provide arch_prctl() interface for LAM Date: Tue, 16 Aug 2022 03:10:21 +0300 Message-Id: <20220816001021.9476-1-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220815041803.17954-7-kirill.shutemov@linux.intel.com> References: <20220815041803.17954-7-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add a couple of arch_prctl() handles: - ARCH_ENABLE_TAGGED_ADDR enabled LAM. The argument is required number of tag bits. It is rounded up to the nearest LAM mode that can provide it. For now only LAM_U57 is supported, with 6 tag bits. - ARCH_GET_UNTAG_MASK returns untag mask. It can indicates where tag bits located in the address. - ARCH_GET_MAX_TAG_BITS returns the maximum tag bits user can request. Zero if LAM is not supported. Signed-off-by: Kirill A. Shutemov --- v6.1: - Drop redundant smb_mb() in prctl_enable_tagged_addr(); --- arch/x86/include/uapi/asm/prctl.h | 4 ++ arch/x86/kernel/process_64.c | 62 ++++++++++++++++++++++++++++++- 2 files changed, 65 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/uapi/asm/prctl.h b/arch/x86/include/uapi/asm/prctl.h index 500b96e71f18..a31e27b95b19 100644 --- a/arch/x86/include/uapi/asm/prctl.h +++ b/arch/x86/include/uapi/asm/prctl.h @@ -20,4 +20,8 @@ #define ARCH_MAP_VDSO_32 0x2002 #define ARCH_MAP_VDSO_64 0x2003 +#define ARCH_GET_UNTAG_MASK 0x4001 +#define ARCH_ENABLE_TAGGED_ADDR 0x4002 +#define ARCH_GET_MAX_TAG_BITS 0x4003 + #endif /* _ASM_X86_PRCTL_H */ diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 1962008fe743..28b9657ce2d0 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -742,6 +742,57 @@ static long prctl_map_vdso(const struct vdso_image *image, unsigned long addr) } #endif +static void enable_lam_func(void *mm) +{ + struct mm_struct *loaded_mm = this_cpu_read(cpu_tlbstate.loaded_mm); + unsigned long lam_mask; + unsigned long cr3; + + if (loaded_mm != mm) + return; + + lam_mask = READ_ONCE(loaded_mm->context.lam_cr3_mask); + + /* Update CR3 to get LAM active on the CPU */ + cr3 = __read_cr3(); + cr3 &= ~(X86_CR3_LAM_U48 | X86_CR3_LAM_U57); + cr3 |= lam_mask; + write_cr3(cr3); + set_tlbstate_cr3_lam_mask(lam_mask); +} + +static int prctl_enable_tagged_addr(struct mm_struct *mm, unsigned long nr_bits) +{ + int ret = 0; + + if (!cpu_feature_enabled(X86_FEATURE_LAM)) + return -ENODEV; + + mutex_lock(&mm->context.lock); + + /* Already enabled? */ + if (mm->context.lam_cr3_mask) { + ret = -EBUSY; + goto out; + } + + if (!nr_bits) { + ret = -EINVAL; + goto out; + } else if (nr_bits <= 6) { + mm->context.lam_cr3_mask = X86_CR3_LAM_U57; + mm->context.untag_mask = ~GENMASK(62, 57); + } else { + ret = -EINVAL; + goto out; + } + + on_each_cpu_mask(mm_cpumask(mm), enable_lam_func, mm, true); +out: + mutex_unlock(&mm->context.lock); + return ret; +} + long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2) { int ret = 0; @@ -829,7 +880,16 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2) case ARCH_MAP_VDSO_64: return prctl_map_vdso(&vdso_image_64, arg2); #endif - + case ARCH_GET_UNTAG_MASK: + return put_user(task->mm->context.untag_mask, + (unsigned long __user *)arg2); + case ARCH_ENABLE_TAGGED_ADDR: + return prctl_enable_tagged_addr(task->mm, arg2); + case ARCH_GET_MAX_TAG_BITS: + if (!cpu_feature_enabled(X86_FEATURE_LAM)) + return put_user(0, (unsigned long __user *)arg2); + else + return put_user(6, (unsigned long __user *)arg2); default: ret = -EINVAL; break; -- 2.35.1