From nobody Sun Feb 8 20:13:25 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 2F1E4C6FD1C for ; Wed, 22 Mar 2023 17:05:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229796AbjCVRFj (ORCPT ); Wed, 22 Mar 2023 13:05:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59310 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231477AbjCVREt (ORCPT ); Wed, 22 Mar 2023 13:04:49 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4FEF9664C1; Wed, 22 Mar 2023 10:04:01 -0700 (PDT) Date: Wed, 22 Mar 2023 17:03:08 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1679504589; 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=pr1emCY0QATpNZW2xfHtncUuLHRp40r3mqoT3B56WhI=; b=1Og4YKI9KdUOl/x+FdtpEARyno1MugJHoj8VVs1M3C5Xfq2jFdLZ6Zv1pIwN5jkpmbACSK dnyBUNzlVzwVxYpwrpQQcI+d6vwxtDDPH5CfCtM76uHDHaPE7HdNe4yx58+yVlSivQNnnT b/s4zJAF4xTn98uDEuhp3qzxbKGW8GRnVFIVBGR4Cc7cx2WTl+sxBrw3rVfNF1e7FvVH39 w3DXVA+7Ver0o5VZ1mTEY+V1FMaoNnD9yW5Dy1lQSMD+Mfn2d4axmwjTvZLDPTG/RZ8/cb 1RRP0Q+vsQVGVj2HwuU6tC7GqramEDUVGemv2tHqD7LZBiWPuqYyG7LsPySabg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1679504589; 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=pr1emCY0QATpNZW2xfHtncUuLHRp40r3mqoT3B56WhI=; b=XF22txeVufV7LoP+SN+QLacx1ZkW6i5bNaK/NgGQEuCxnaqk0pdnP8ZiIzKgnDEdPGqALG 58P47G9sHDE8GuCg== From: "tip-bot2 for Kirill A. Shutemov" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/mm] x86: Allow atomic MM_CONTEXT flags setting Cc: "Kirill A. Shutemov" , Dave Hansen , "Peter Zijlstra (Intel)" , Alexander Potapenko , x86@kernel.org, linux-kernel@vger.kernel.org MIME-Version: 1.0 Message-ID: <167950458866.5837.13516431668563411441.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/mm branch of tip: Commit-ID: 5ef495e55f07aa117fdd8e187c9901cefc02fe0a Gitweb: https://git.kernel.org/tip/5ef495e55f07aa117fdd8e187c9901cef= c02fe0a Author: Kirill A. Shutemov AuthorDate: Sun, 12 Mar 2023 14:25:57 +03:00 Committer: Dave Hansen CommitterDate: Thu, 16 Mar 2023 13:08:39 -07:00 x86: Allow atomic MM_CONTEXT flags setting So far there's no need in atomic setting of MM context flags in mm_context_t::flags. The flags set early in exec and never change after that. LAM enabling requires atomic flag setting. The upcoming flag MM_CONTEXT_FORCE_TAGGED_SVA can be set much later in the process lifetime where multiple threads exist. Convert the field to unsigned long and do MM_CONTEXT_* accesses with __set_bit() and test_bit(). No functional changes. Signed-off-by: Kirill A. Shutemov Signed-off-by: Dave Hansen Acked-by: Peter Zijlstra (Intel) Tested-by: Alexander Potapenko Link: https://lore.kernel.org/all/20230312112612.31869-3-kirill.shutemov%40= linux.intel.com --- arch/x86/entry/vsyscall/vsyscall_64.c | 2 +- arch/x86/include/asm/mmu.h | 6 +++--- arch/x86/include/asm/mmu_context.h | 2 +- arch/x86/kernel/process_64.c | 4 ++-- 4 files changed, 7 insertions(+), 7 deletions(-) diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c b/arch/x86/entry/vsyscal= l/vsyscall_64.c index d234ca7..e0ca812 100644 --- a/arch/x86/entry/vsyscall/vsyscall_64.c +++ b/arch/x86/entry/vsyscall/vsyscall_64.c @@ -317,7 +317,7 @@ static struct vm_area_struct gate_vma __ro_after_init = =3D { struct vm_area_struct *get_gate_vma(struct mm_struct *mm) { #ifdef CONFIG_COMPAT - if (!mm || !(mm->context.flags & MM_CONTEXT_HAS_VSYSCALL)) + if (!mm || !test_bit(MM_CONTEXT_HAS_VSYSCALL, &mm->context.flags)) return NULL; #endif if (vsyscall_mode =3D=3D NONE) diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h index 5d74946..efa3eae 100644 --- a/arch/x86/include/asm/mmu.h +++ b/arch/x86/include/asm/mmu.h @@ -9,9 +9,9 @@ #include =20 /* Uprobes on this MM assume 32-bit code */ -#define MM_CONTEXT_UPROBE_IA32 BIT(0) +#define MM_CONTEXT_UPROBE_IA32 0 /* vsyscall page is accessible on this MM */ -#define MM_CONTEXT_HAS_VSYSCALL BIT(1) +#define MM_CONTEXT_HAS_VSYSCALL 1 =20 /* * x86 has arch-specific MMU state beyond what lives in mm_struct. @@ -39,7 +39,7 @@ typedef struct { #endif =20 #ifdef CONFIG_X86_64 - unsigned short flags; + unsigned long flags; #endif =20 struct mutex lock; diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_= context.h index e01aa74..b4e4a0c 100644 --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -182,7 +182,7 @@ static inline void arch_exit_mmap(struct mm_struct *mm) static inline bool is_64bit_mm(struct mm_struct *mm) { return !IS_ENABLED(CONFIG_IA32_EMULATION) || - !(mm->context.flags & MM_CONTEXT_UPROBE_IA32); + !test_bit(MM_CONTEXT_UPROBE_IA32, &mm->context.flags); } #else static inline bool is_64bit_mm(struct mm_struct *mm) diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index bb65a68..cd34bcf 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -671,7 +671,7 @@ void set_personality_64bit(void) task_pt_regs(current)->orig_ax =3D __NR_execve; current_thread_info()->status &=3D ~TS_COMPAT; if (current->mm) - current->mm->context.flags =3D MM_CONTEXT_HAS_VSYSCALL; + __set_bit(MM_CONTEXT_HAS_VSYSCALL, ¤t->mm->context.flags); =20 /* TBD: overwrites user setup. Should have two bits. But 64bit processes have always behaved this way, @@ -708,7 +708,7 @@ static void __set_personality_ia32(void) * uprobes applied to this MM need to know this and * cannot use user_64bit_mode() at that time. */ - current->mm->context.flags =3D MM_CONTEXT_UPROBE_IA32; + __set_bit(MM_CONTEXT_UPROBE_IA32, ¤t->mm->context.flags); } =20 current->personality |=3D force_personality32;