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=-11.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 7B45FC432C3 for ; Sat, 16 Nov 2019 11:52:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5C1EA206A4 for ; Sat, 16 Nov 2019 11:52:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727836AbfKPLwh (ORCPT ); Sat, 16 Nov 2019 06:52:37 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:45241 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727510AbfKPLv1 (ORCPT ); Sat, 16 Nov 2019 06:51:27 -0500 Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1iVwbs-00027S-Lg; Sat, 16 Nov 2019 12:51:24 +0100 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 078761C1902; Sat, 16 Nov 2019 12:51:23 +0100 (CET) Date: Sat, 16 Nov 2019 11:51:22 -0000 From: "tip-bot2 for Thomas Gleixner" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/iopl] x86/ioperm: Remove bitmap if all permissions dropped Cc: Thomas Gleixner , Andy Lutomirski , Ingo Molnar , Borislav Petkov , linux-kernel@vger.kernel.org MIME-Version: 1.0 Message-ID: <157390508298.12247.1768616194723624483.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/iopl branch of tip: Commit-ID: ea5f1cd7ab494f65f50f338299eabb40ad6a1767 Gitweb: https://git.kernel.org/tip/ea5f1cd7ab494f65f50f338299eabb40ad6a1767 Author: Thomas Gleixner AuthorDate: Mon, 11 Nov 2019 23:03:24 +01:00 Committer: Thomas Gleixner CommitterDate: Sat, 16 Nov 2019 11:24:03 +01:00 x86/ioperm: Remove bitmap if all permissions dropped If ioperm() results in a bitmap with all bits set (no permissions to any I/O port), then handling that bitmap on context switch and exit to user mode is pointless. Drop it. Move the bitmap exit handling to the ioport code and reuse it for both the thread exit path and dropping it. This allows to reuse this code for the upcoming iopl() emulation. Signed-off-by: Thomas Gleixner Acked-by: Andy Lutomirski --- arch/x86/include/asm/io_bitmap.h | 2 ++ arch/x86/kernel/ioport.c | 19 ++++++++++++++++++- arch/x86/kernel/process.c | 17 +++-------------- 3 files changed, 23 insertions(+), 15 deletions(-) diff --git a/arch/x86/include/asm/io_bitmap.h b/arch/x86/include/asm/io_bitmap.h index 6d82a37..784a88e 100644 --- a/arch/x86/include/asm/io_bitmap.h +++ b/arch/x86/include/asm/io_bitmap.h @@ -11,6 +11,8 @@ struct io_bitmap { unsigned long bitmap[IO_BITMAP_LONGS]; }; +void io_bitmap_exit(void); + void tss_update_io_bitmap(void); #endif diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c index 198bead..f9fc69a 100644 --- a/arch/x86/kernel/ioport.c +++ b/arch/x86/kernel/ioport.c @@ -16,6 +16,18 @@ static atomic64_t io_bitmap_sequence; +void io_bitmap_exit(void) +{ + struct io_bitmap *iobm = current->thread.io_bitmap; + + current->thread.io_bitmap = NULL; + clear_thread_flag(TIF_IO_BITMAP); + preempt_disable(); + tss_update_io_bitmap(); + preempt_enable(); + kfree(iobm); +} + /* * this changes the io permissions bitmap in the current task. */ @@ -61,11 +73,16 @@ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on) * Search for a (possibly new) maximum. This is simple and stupid, * to keep it obviously correct: */ - max_long = 0; + max_long = UINT_MAX; for (i = 0; i < IO_BITMAP_LONGS; i++) { if (iobm->bitmap[i] != ~0UL) max_long = i; } + /* All permissions dropped? */ + if (max_long == UINT_MAX) { + io_bitmap_exit(); + return 0; + } iobm->max = (max_long + 1) * sizeof(unsigned long); diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 108af91..7ba4d54 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -102,21 +102,10 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) void exit_thread(struct task_struct *tsk) { struct thread_struct *t = &tsk->thread; - struct io_bitmap *iobm = t->io_bitmap; struct fpu *fpu = &t->fpu; - struct tss_struct *tss; - - if (iobm) { - preempt_disable(); - tss = this_cpu_ptr(&cpu_tss_rw); - - t->io_bitmap = NULL; - clear_thread_flag(TIF_IO_BITMAP); - /* Invalidate the io bitmap base in the TSS */ - tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_INVALID; - preempt_enable(); - kfree(iobm); - } + + if (test_thread_flag(TIF_IO_BITMAP)) + io_bitmap_exit(); free_vm86(t);