From patchwork Tue Jan 5 16:22:18 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 7956191 Return-Path: X-Original-To: patchwork-linux-sh@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 6F2E5BEEE5 for ; Tue, 5 Jan 2016 16:22:24 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 8D73320219 for ; Tue, 5 Jan 2016 16:22:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 86F4420225 for ; Tue, 5 Jan 2016 16:22:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751868AbcAEQWW (ORCPT ); Tue, 5 Jan 2016 11:22:22 -0500 Received: from mx1.redhat.com ([209.132.183.28]:57831 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751704AbcAEQWV (ORCPT ); Tue, 5 Jan 2016 11:22:21 -0500 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (Postfix) with ESMTPS id 66649461C4; Tue, 5 Jan 2016 16:22:21 +0000 (UTC) Received: from redhat.com (vpn1-5-187.ams2.redhat.com [10.36.5.187]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with SMTP id u05GMIKs007738; Tue, 5 Jan 2016 11:22:19 -0500 Date: Tue, 5 Jan 2016 18:22:18 +0200 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Thomas Gleixner , linux-sh@vger.kernel.org Subject: [PATCH] sh: support a 2-byte xchg Message-ID: <1452010849-25546-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Disposition: inline X-Mutt-Fcc: =sent X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP At the moment, xchg on sh only supports 4 and 1 byte values, so using it from smp_store_mb means attempts to store a 2 byte value using this macro fail. And this happens to be exactly what virtio drivers want to do. Add a 2-byte xchg variant. Suggested-by: Peter Zijlstra Signed-off-by: Michael S. Tsirkin --- Notes: - compiled only - arch maintainers, this is a dependency of virtio driver work, so please ack, do not cherry-pick arch/sh/include/asm/cmpxchg-grb.h | 22 ++++++++++++++++++++++ arch/sh/include/asm/cmpxchg-irq.h | 11 +++++++++++ arch/sh/include/asm/cmpxchg-llsc.h | 21 +++++++++++++++++++++ arch/sh/include/asm/cmpxchg.h | 3 +++ 4 files changed, 57 insertions(+) diff --git a/arch/sh/include/asm/cmpxchg-grb.h b/arch/sh/include/asm/cmpxchg-grb.h index f848dec..2ed557b 100644 --- a/arch/sh/include/asm/cmpxchg-grb.h +++ b/arch/sh/include/asm/cmpxchg-grb.h @@ -23,6 +23,28 @@ static inline unsigned long xchg_u32(volatile u32 *m, unsigned long val) return retval; } +static inline unsigned long xchg_u16(volatile u16 *m, unsigned long val) +{ + unsigned long retval; + + __asm__ __volatile__ ( + " .align 2 \n\t" + " mova 1f, r0 \n\t" /* r0 = end point */ + " mov r15, r1 \n\t" /* r1 = saved sp */ + " mov #-6, r15 \n\t" /* LOGIN */ + " mov.w @%1, %0 \n\t" /* load old value */ + " extu.w %0, %0 \n\t" /* extend as unsigned */ + " mov.w %2, @%1 \n\t" /* store new value */ + "1: mov r1, r15 \n\t" /* LOGOUT */ + : "=&r" (retval), + "+r" (m), + "+r" (val) /* inhibit r15 overloading */ + : + : "memory" , "r0", "r1"); + + return retval; +} + static inline unsigned long xchg_u8(volatile u8 *m, unsigned long val) { unsigned long retval; diff --git a/arch/sh/include/asm/cmpxchg-irq.h b/arch/sh/include/asm/cmpxchg-irq.h index bd11f63..f888772 100644 --- a/arch/sh/include/asm/cmpxchg-irq.h +++ b/arch/sh/include/asm/cmpxchg-irq.h @@ -14,6 +14,17 @@ static inline unsigned long xchg_u32(volatile u32 *m, unsigned long val) return retval; } +static inline unsigned long xchg_u16(volatile u16 *m, unsigned long val) +{ + unsigned long flags, retval; + + local_irq_save(flags); + retval = *m; + *m = val; + local_irq_restore(flags); + return retval; +} + static inline unsigned long xchg_u8(volatile u8 *m, unsigned long val) { unsigned long flags, retval; diff --git a/arch/sh/include/asm/cmpxchg-llsc.h b/arch/sh/include/asm/cmpxchg-llsc.h index 4713666..dab6c58 100644 --- a/arch/sh/include/asm/cmpxchg-llsc.h +++ b/arch/sh/include/asm/cmpxchg-llsc.h @@ -22,6 +22,27 @@ static inline unsigned long xchg_u32(volatile u32 *m, unsigned long val) return retval; } +static inline unsigned long xchg_u16(volatile u16 *m, unsigned long val) +{ + unsigned long retval; + unsigned long tmp; + + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%2, %0 ! xchg_u16 \n\t" + "mov %0, %1 \n\t" + "mov %3, %0 \n\t" + "movco.l %0, @%2 \n\t" + "bf 1b \n\t" + "synco \n\t" + : "=&z"(tmp), "=&r" (retval) + : "r" (m), "r" (val & 0xffff) + : "t", "memory" + ); + + return retval; +} + static inline unsigned long xchg_u8(volatile u8 *m, unsigned long val) { unsigned long retval; diff --git a/arch/sh/include/asm/cmpxchg.h b/arch/sh/include/asm/cmpxchg.h index 85c97b18..5225916 100644 --- a/arch/sh/include/asm/cmpxchg.h +++ b/arch/sh/include/asm/cmpxchg.h @@ -27,6 +27,9 @@ extern void __xchg_called_with_bad_pointer(void); case 4: \ __xchg__res = xchg_u32(__xchg_ptr, x); \ break; \ + case 2: \ + __xchg__res = xchg_u16(__xchg_ptr, x); \ + break; \ case 1: \ __xchg__res = xchg_u8(__xchg_ptr, x); \ break; \