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,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 CB2F6C4338F for ; Wed, 25 Aug 2021 16:02:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A5515613CD for ; Wed, 25 Aug 2021 16:02:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240786AbhHYQDG (ORCPT ); Wed, 25 Aug 2021 12:03:06 -0400 Received: from mga07.intel.com ([134.134.136.100]:32818 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242131AbhHYQCI (ORCPT ); Wed, 25 Aug 2021 12:02:08 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10087"; a="281267329" X-IronPort-AV: E=Sophos;i="5.84,351,1620716400"; d="scan'208";a="281267329" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Aug 2021 09:00:49 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.84,351,1620716400"; d="scan'208";a="494317341" Received: from chang-linux-3.sc.intel.com ([172.25.66.175]) by fmsmga008.fm.intel.com with ESMTP; 25 Aug 2021 09:00:48 -0700 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, lenb@kernel.org, dave.hansen@intel.com, thiago.macieira@intel.com, jing2.liu@intel.com, ravi.v.shankar@intel.com, linux-kernel@vger.kernel.org, chang.seok.bae@intel.com Subject: [PATCH v10 28/28] x86/arch_prctl: ARCH_GET_FEATURES_WITH_KERNEL_ASSISTANCE Date: Wed, 25 Aug 2021 08:54:13 -0700 Message-Id: <20210825155413.19673-29-chang.seok.bae@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210825155413.19673-1-chang.seok.bae@intel.com> References: <20210825155413.19673-1-chang.seok.bae@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org arch_prctl(ARCH_GET_FEATURES_WITH_KERNEL_ASSISTANCE, u64 *bitmask) Return the bitmask of the kernel-supported features. If XSAVE is disabled, the bitmask indicates only legacy states. Suggested-by: Borislav Petkov Signed-off-by: Chang S. Bae Cc: x86@kernel.org Cc: linux-kernel@vger.kernel.org --- Changes from v9: * Add as a new patch. (Thiago Macieira and Borislav Petkov) --- arch/x86/include/asm/fpu/xstate.h | 1 + arch/x86/include/uapi/asm/prctl.h | 23 ++++++++--------- arch/x86/kernel/fpu/xstate.c | 41 +++++++++++++++++++------------ arch/x86/kernel/process.c | 2 ++ 4 files changed, 40 insertions(+), 27 deletions(-) diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index 013478c1aa42..4aa7049cc079 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -194,6 +194,7 @@ static inline bool dynamic_state_permitted(struct task_struct *tsk, u64 state_ma } void reset_dynamic_state_perm(struct task_struct *tsk); +u64 get_features_mask_uabi(void); long set_group_state_perm(struct task_struct *tsk, u64 state_perm); u64 get_group_state_perm(struct task_struct *tsk); diff --git a/arch/x86/include/uapi/asm/prctl.h b/arch/x86/include/uapi/asm/prctl.h index c73e141ce90a..6912d5fe85f3 100644 --- a/arch/x86/include/uapi/asm/prctl.h +++ b/arch/x86/include/uapi/asm/prctl.h @@ -2,19 +2,20 @@ #ifndef _ASM_X86_PRCTL_H #define _ASM_X86_PRCTL_H -#define ARCH_SET_GS 0x1001 -#define ARCH_SET_FS 0x1002 -#define ARCH_GET_FS 0x1003 -#define ARCH_GET_GS 0x1004 +#define ARCH_SET_GS 0x1001 +#define ARCH_SET_FS 0x1002 +#define ARCH_GET_FS 0x1003 +#define ARCH_GET_GS 0x1004 -#define ARCH_GET_CPUID 0x1011 -#define ARCH_SET_CPUID 0x1012 +#define ARCH_GET_CPUID 0x1011 +#define ARCH_SET_CPUID 0x1012 -#define ARCH_SET_STATE_ENABLE 0x1021 -#define ARCH_GET_STATE_ENABLE 0x1022 +#define ARCH_GET_FEATURES_WITH_KERNEL_ASSISTANCE 0x1020 +#define ARCH_SET_STATE_ENABLE 0x1021 +#define ARCH_GET_STATE_ENABLE 0x1022 -#define ARCH_MAP_VDSO_X32 0x2001 -#define ARCH_MAP_VDSO_32 0x2002 -#define ARCH_MAP_VDSO_64 0x2003 +#define ARCH_MAP_VDSO_X32 0x2001 +#define ARCH_MAP_VDSO_32 0x2002 +#define ARCH_MAP_VDSO_64 0x2003 #endif /* _ASM_X86_PRCTL_H */ diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 2c62872e4fef..6622366d51ae 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -1297,6 +1297,25 @@ int realloc_xstate_buffer(struct fpu *fpu, u64 mask) return 0; } +/** + * get_features_mask_uabi - Get feature list that the kernel supports + * Return: A bitmap to indicate which state is available + * + */ +u64 get_features_mask_uabi(void) +{ + if (!cpu_feature_enabled(X86_FEATURE_FPU)) + return 0; + + if (use_xsave()) + return xfeatures_mask_uabi(); + + if (use_fxsr()) + return XFEATURE_MASK_FPSSE; + + return XFEATURE_MASK_FP; +} + /** * set_group_state_perm - Set a per-process permission for dynamic user * states. @@ -1306,16 +1325,7 @@ int realloc_xstate_buffer(struct fpu *fpu, u64 mask) */ long set_group_state_perm(struct task_struct *tsk, u64 state_perm) { - u64 features_mask; - - if (!cpu_feature_enabled(X86_FEATURE_FPU)) - features_mask = 0; - else if (use_xsave()) - features_mask = xfeatures_mask_uabi(); - else if (use_fxsr()) - features_mask = XFEATURE_MASK_FPSSE; - else - features_mask = XFEATURE_MASK_FP; + u64 features_mask = get_features_mask_uabi(); if (state_perm & ~features_mask) return -EINVAL; @@ -1365,17 +1375,16 @@ void reset_dynamic_state_perm(struct task_struct *tsk) */ u64 get_group_state_perm(struct task_struct *tsk) { + u64 mask = get_features_mask_uabi(); + if (!cpu_feature_enabled(X86_FEATURE_FPU)) return 0; if (use_xsave()) - return (xfeatures_mask_uabi() & ~xfeatures_mask_user_dynamic) | + return (mask & ~xfeatures_mask_user_dynamic) | get_group_dynamic_state_perm(tsk); - - if (use_fxsr()) - return XFEATURE_MASK_FPSSE; - - return XFEATURE_MASK_FP; + else + return mask; } static void copy_feature(bool from_xstate, struct membuf *to, void *xstate, diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index beab1bf76d1a..544b0c4f3aed 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -1023,6 +1023,8 @@ long do_arch_prctl_common(struct task_struct *task, int option, return get_cpuid_mode(); case ARCH_SET_CPUID: return set_cpuid_mode(task, arg2); + case ARCH_GET_FEATURES_WITH_KERNEL_ASSISTANCE: + return put_user(get_features_mask_uabi(), (unsigned long __user *)arg2); case ARCH_SET_STATE_ENABLE: return set_group_state_perm(task, arg2); case ARCH_GET_STATE_ENABLE: -- 2.17.1