From nobody Sun Feb 8 11:59:18 2026 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 CB049EB64D7 for ; Fri, 16 Jun 2023 19:17:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343842AbjFPTRZ (ORCPT ); Fri, 16 Jun 2023 15:17:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47938 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233340AbjFPTQ5 (ORCPT ); Fri, 16 Jun 2023 15:16:57 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 87BB13A8D; Fri, 16 Jun 2023 12:16:55 -0700 (PDT) Date: Fri, 16 Jun 2023 19:16:53 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1686943014; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=9RGa4VIIDFiHWyfftGTzzfEoJi9C11JmGHAo2XjXk4Y=; b=dGf1xmstP0MrdO9iao1Vgav9l0nnH6xVZ1cxTTipfppvgqC26pGJykdQnm+ZwQEWvM8BIF iWUo4H3asZk6OPeBy/N4l8sR7GLylqcilgs76YHedRxIE8kjF1qFoahoRXeG8kW9td3V5m yqivJQweqKg/z4NThQhk2K1PnO+ZdpWJH6GFLbUuDSTU+ODiOaeOKDP4naAl78YicZC+TY n+M3qrbNpiv7h4a1jWbdQ75nqpgZ/MfQFnbcc6dY2JuXS59OhMrtHG5C3k0QdSXAyVIKfy 6SY91gHH6FEdXgbORY8aXkBsxP180rU9KgIEYyjj8VVWnwhFa1uWaKGYAGFC+w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1686943014; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=9RGa4VIIDFiHWyfftGTzzfEoJi9C11JmGHAo2XjXk4Y=; b=JSQxx+Bep9aSokVJaXquW1kGQVX7dBdU7xZUdf+UFGJEOM011SzpGyF0Zoq7RgjnoZP2q5 YHJG2CI+RX4r9qAw== From: "tip-bot2 for Rick Edgecombe" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/shstk] x86: Expose thread features in /proc/$PID/status Cc: "Kirill A. Shutemov" , Rick Edgecombe , Dave Hansen , "Borislav Petkov (AMD)" , Kees Cook , "Mike Rapoport (IBM)" , Pengfei Xu , John Allen , x86@kernel.org, linux-kernel@vger.kernel.org MIME-Version: 1.0 Message-ID: <168694301349.404.16571113627709344472.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/shstk branch of tip: Commit-ID: eec387cbf905036a3f6322c6e3b83d03ff9d19fb Gitweb: https://git.kernel.org/tip/eec387cbf905036a3f6322c6e3b83d03f= f9d19fb Author: Rick Edgecombe AuthorDate: Mon, 12 Jun 2023 17:11:02 -07:00 Committer: Dave Hansen CommitterDate: Thu, 15 Jun 2023 16:31:34 -07:00 x86: Expose thread features in /proc/$PID/status Applications and loaders can have logic to decide whether to enable shadow stack. They usually don't report whether shadow stack has been enabled or not, so there is no way to verify whether an application actually is protected by shadow stack. Add two lines in /proc/$PID/status to report enabled and locked features. Since, this involves referring to arch specific defines in asm/prctl.h, implement an arch breakout to emit the feature lines. [Switched to CET, added to commit log] Co-developed-by: Kirill A. Shutemov Signed-off-by: Kirill A. Shutemov Signed-off-by: Rick Edgecombe Signed-off-by: Dave Hansen Reviewed-by: Borislav Petkov (AMD) Reviewed-by: Kees Cook Acked-by: Mike Rapoport (IBM) Tested-by: Pengfei Xu Tested-by: John Allen Tested-by: Kees Cook Link: https://lore.kernel.org/all/20230613001108.3040476-37-rick.p.edgecomb= e%40intel.com --- arch/x86/kernel/cpu/proc.c | 23 +++++++++++++++++++++++ fs/proc/array.c | 6 ++++++ include/linux/proc_fs.h | 2 ++ 3 files changed, 31 insertions(+) diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c index 099b6f0..31c0e68 100644 --- a/arch/x86/kernel/cpu/proc.c +++ b/arch/x86/kernel/cpu/proc.c @@ -4,6 +4,8 @@ #include #include #include +#include +#include =20 #include "cpu.h" =20 @@ -175,3 +177,24 @@ const struct seq_operations cpuinfo_op =3D { .stop =3D c_stop, .show =3D show_cpuinfo, }; + +#ifdef CONFIG_X86_USER_SHADOW_STACK +static void dump_x86_features(struct seq_file *m, unsigned long features) +{ + if (features & ARCH_SHSTK_SHSTK) + seq_puts(m, "shstk "); + if (features & ARCH_SHSTK_WRSS) + seq_puts(m, "wrss "); +} + +void arch_proc_pid_thread_features(struct seq_file *m, struct task_struct = *task) +{ + seq_puts(m, "x86_Thread_features:\t"); + dump_x86_features(m, task->thread.features); + seq_putc(m, '\n'); + + seq_puts(m, "x86_Thread_features_locked:\t"); + dump_x86_features(m, task->thread.features_locked); + seq_putc(m, '\n'); +} +#endif /* CONFIG_X86_USER_SHADOW_STACK */ diff --git a/fs/proc/array.c b/fs/proc/array.c index d35bbf3..2c2efbe 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -431,6 +431,11 @@ static inline void task_untag_mask(struct seq_file *m,= struct mm_struct *mm) seq_printf(m, "untag_mask:\t%#lx\n", mm_untag_mask(mm)); } =20 +__weak void arch_proc_pid_thread_features(struct seq_file *m, + struct task_struct *task) +{ +} + int proc_pid_status(struct seq_file *m, struct pid_namespace *ns, struct pid *pid, struct task_struct *task) { @@ -455,6 +460,7 @@ int proc_pid_status(struct seq_file *m, struct pid_name= space *ns, task_cpus_allowed(m, task); cpuset_task_status_allowed(m, task); task_context_switch_counts(m, task); + arch_proc_pid_thread_features(m, task); return 0; } =20 diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index 0260f5e..80ff8e5 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -158,6 +158,8 @@ int proc_pid_arch_status(struct seq_file *m, struct pid= _namespace *ns, struct pid *pid, struct task_struct *task); #endif /* CONFIG_PROC_PID_ARCH_STATUS */ =20 +void arch_proc_pid_thread_features(struct seq_file *m, struct task_struct = *task); + #else /* CONFIG_PROC_FS */ =20 static inline void proc_root_init(void)