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=-8.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 A45BCC433E0 for ; Fri, 12 Feb 2021 00:04:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7D74264E4B for ; Fri, 12 Feb 2021 00:04:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229872AbhBLAEj convert rfc822-to-8bit (ORCPT ); Thu, 11 Feb 2021 19:04:39 -0500 Received: from szxga02-in.huawei.com ([45.249.212.188]:3018 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229623AbhBLAEh (ORCPT ); Thu, 11 Feb 2021 19:04:37 -0500 Received: from DGGEMM402-HUB.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4DcDG32f6fzR6mN; Fri, 12 Feb 2021 08:02:35 +0800 (CST) Received: from dggemi711-chm.china.huawei.com (10.3.20.110) by DGGEMM402-HUB.china.huawei.com (10.3.20.210) with Microsoft SMTP Server (TLS) id 14.3.498.0; Fri, 12 Feb 2021 08:03:52 +0800 Received: from dggemi761-chm.china.huawei.com (10.1.198.147) by dggemi711-chm.china.huawei.com (10.3.20.110) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2106.2; Fri, 12 Feb 2021 08:03:52 +0800 Received: from dggemi761-chm.china.huawei.com ([10.9.49.202]) by dggemi761-chm.china.huawei.com ([10.9.49.202]) with mapi id 15.01.2106.006; Fri, 12 Feb 2021 08:03:52 +0800 From: "Song Bao Hua (Barry Song)" To: Finn Thain CC: tanxiaofei , "jejb@linux.ibm.com" , "martin.petersen@oracle.com" , "linux-scsi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linuxarm@openeuler.org" , "linux-m68k@vger.kernel.org" Subject: RE: Re: [PATCH for-next 00/32] spin lock usage optimization for SCSI drivers Thread-Topic: Re: [PATCH for-next 00/32] spin lock usage optimization for SCSI drivers Thread-Index: AdcAYpckfegWyL1RTeK8yhWOZkcCaAAK/seAABDAZzA= Date: Fri, 12 Feb 2021 00:03:52 +0000 Message-ID: <0d104f0e26134b1ea9c530be895e65d1@hisilicon.com> References: <417fa728c3ff4418ac87e0d409b5a084@hisilicon.com> In-Reply-To: Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.126.201.23] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org > -----Original Message----- > From: Finn Thain [mailto:fthain@telegraphics.com.au] > Sent: Friday, February 12, 2021 12:57 PM > To: Song Bao Hua (Barry Song) > Cc: tanxiaofei ; jejb@linux.ibm.com; > martin.petersen@oracle.com; linux-scsi@vger.kernel.org; > linux-kernel@vger.kernel.org; linuxarm@openeuler.org; > linux-m68k@vger.kernel.org > Subject: RE: Re: [PATCH for-next 00/32] spin lock usage optimization for SCSI > drivers > > > On Thu, 11 Feb 2021, Song Bao Hua (Barry Song) wrote: > > > > > Actually in m68k, I also saw its IRQ entry disabled interrupts by > > ' move #0x2700,%sr /* disable intrs */' > > > > arch/m68k/include/asm/entry.h: > > > > .macro SAVE_ALL_SYS > > move #0x2700,%sr /* disable intrs */ > > btst #5,%sp@(2) /* from user? */ > > bnes 6f /* no, skip */ > > movel %sp,sw_usp /* save user sp */ > > ... > > > > .macro SAVE_ALL_INT > > SAVE_ALL_SYS > > moveq #-1,%d0 /* not system call entry */ > > movel %d0,%sp@(PT_OFF_ORIG_D0) > > .endm > > > > arch/m68k/kernel/entry.S: > > > > /* This is the main interrupt handler for autovector interrupts */ > > > > ENTRY(auto_inthandler) > > SAVE_ALL_INT > > GET_CURRENT(%d0) > > | put exception # in d0 > > bfextu %sp@(PT_OFF_FORMATVEC){#4,#10},%d0 > > subw #VEC_SPUR,%d0 > > > > movel %sp,%sp@- > > movel %d0,%sp@- | put vector # on stack > > auto_irqhandler_fixup = . + 2 > > jsr do_IRQ | process the IRQ > > addql #8,%sp | pop parameters off stack > > jra ret_from_exception > > > > So my question is that " move #0x2700,%sr" is actually disabling > > all interrupts? And is m68k actually running irq handlers > > with interrupts disabled? > > > > When sonic_interrupt() executes, the IPL is 2 or 3 (since either IRQ may > be involved). That is, SR & 0x700 is 0x200 or 0x300. The level 3 interrupt > may interrupt execution of the level 2 handler so an irq lock is used to > avoid re-entrance. > > This patch, > > diff --git a/drivers/net/ethernet/natsemi/sonic.c > b/drivers/net/ethernet/natsemi/sonic.c > index d17d1b4f2585..041354647bad 100644 > --- a/drivers/net/ethernet/natsemi/sonic.c > +++ b/drivers/net/ethernet/natsemi/sonic.c > @@ -355,6 +355,8 @@ static irqreturn_t sonic_interrupt(int irq, void *dev_id) > */ > spin_lock_irqsave(&lp->lock, flags); > > + printk_once(KERN_INFO "%s: %08lx\n", __func__, flags); > + > status = SONIC_READ(SONIC_ISR) & SONIC_IMR_DEFAULT; > if (!status) { > spin_unlock_irqrestore(&lp->lock, flags); > > produces this output, > > [ 3.800000] sonic_interrupt: 00002300 I actually hope you can directly read the register rather than reading a flag which might be a software one not from register. > > I ran that code in QEMU, but experience shows that Apple hardware works > exactly the same. Please do confirm this for yourself, if you still think > the code and comments in sonic_interrupt are wrong. > > > Best Regards > > Barry > > Thanks Barry