From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3yH92c2F9zzDqJ7 for ; Wed, 18 Oct 2017 22:34:47 +1100 (AEDT) Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v9IBY9b7051853 for ; Wed, 18 Oct 2017 07:34:45 -0400 Received: from e18.ny.us.ibm.com (e18.ny.us.ibm.com [129.33.205.208]) by mx0a-001b2d01.pphosted.com with ESMTP id 2dp5fm3cqr-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 18 Oct 2017 07:34:45 -0400 Received: from localhost by e18.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 18 Oct 2017 07:34:44 -0400 From: "Guilherme G. Piccoli" To: linuxppc-dev@lists.ozlabs.org Cc: gpiccoli@linux.vnet.ibm.com, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, brking@linux.vnet.ibm.com Subject: [PATCH] powerpc/xmon: Always enable xmon sysrq trigger Date: Wed, 18 Oct 2017 09:34:36 -0200 Message-Id: <20171018113436.16112-1-gpiccoli@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Distros vary the way they enable SysRq by default - mostly they seem to enable some mask and then majority of the SysRq functions are disabled. For instance, xmon does not even have a mask, and unsless SysRq are completely enabled ( == 1), xmon trigger keeps disabled. Countless times while investigating hangs we needed xmon and it was disabled - machine just got hung and while in serial console, we just couldn't drop to xmon, forcing to a new attempt to reproduce the issue with SysRq fully enabled. This patch "fixes" this by having xmon enabled in all possible masks of SysRq. In other words, xmon trigger will only be disabled if SysRq is 0 (completely disabled). So, while debugging a hung, when one tries to drop to xmon this patch prevents the frustrating message: "This sysrq operation is disabled". Signed-off-by: Guilherme G. Piccoli --- Patch built and tested against powerpc/next. arch/powerpc/xmon/xmon.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 4679aeb84767..780d708472a2 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -3514,6 +3514,7 @@ static struct sysrq_key_op sysrq_xmon_op = { .handler = sysrq_handle_xmon, .help_msg = "xmon(x)", .action_msg = "Entering xmon", + .enable_mask = 0xFFFF, }; static int __init setup_xmon_sysrq(void) -- 2.14.2