From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 3vpKTs2hNtzDq7Z for ; Thu, 23 Mar 2017 06:28:17 +1100 (AEDT) Received: from pps.filterd (m0098414.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v2MJNfCf085596 for ; Wed, 22 Mar 2017 15:28:12 -0400 Received: from e24smtp02.br.ibm.com (e24smtp02.br.ibm.com [32.104.18.86]) by mx0b-001b2d01.pphosted.com with ESMTP id 29bxhytj1h-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 22 Mar 2017 15:28:12 -0400 Received: from localhost by e24smtp02.br.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 22 Mar 2017 16:28:10 -0300 Received: from d24av04.br.ibm.com (d24av04.br.ibm.com [9.8.31.97]) by d24relay04.br.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v2MJS78736503590 for ; Wed, 22 Mar 2017 16:28:07 -0300 Received: from d24av04.br.ibm.com (localhost [127.0.0.1]) by d24av04.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id v2MJS6dJ030390 for ; Wed, 22 Mar 2017 16:28:07 -0300 From: "Guilherme G. Piccoli" To: linuxppc-dev@lists.ozlabs.org Cc: gpiccoli@linux.vnet.ibm.com, xinhui.pan@linux.vnet.ibm.com, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au Subject: [PATCH v4 1/3] powerpc/xmon: Fix an unexpected xmon on/off state change Date: Wed, 22 Mar 2017 16:27:49 -0300 In-Reply-To: <20170322192751.30531-1-gpiccoli@linux.vnet.ibm.com> References: <20170322192751.30531-1-gpiccoli@linux.vnet.ibm.com> Message-Id: <20170322192751.30531-2-gpiccoli@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Pan Xinhui Once xmon is triggered by sysrq-x, it is enabled always afterwards even if it is disabled during boot. This will cause a system reset interrupt fail to dump. So keep xmon in its original state after exit. We have several ways to set xmon on or off. 1) by a build config CONFIG_XMON_DEFAULT. 2) by a boot cmdline with xmon or xmon=early or xmon=on to enable xmon and xmon=off to disable xmon. This value will override that in step 1. 3) by a debugfs interface, as proposed in this patchset. And this value can override those in step 1 and 2. Signed-off-by: Pan Xinhui Signed-off-by: Guilherme G. Piccoli --- v3: changed xmon_off to xmon_on, simplifying the logic [mpe suggestion]. arch/powerpc/xmon/xmon.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 16321ad9e70c..a89db1b3f66d 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -76,6 +76,7 @@ static int xmon_gate; #endif /* CONFIG_SMP */ static unsigned long in_xmon __read_mostly = 0; +static int xmon_on = IS_ENABLED(CONFIG_XMON_DEFAULT); static unsigned long adrs; static int size = 1; @@ -3302,6 +3303,8 @@ static void sysrq_handle_xmon(int key) /* ensure xmon is enabled */ xmon_init(1); debugger(get_irq_regs()); + if (!xmon_on) + xmon_init(0); } static struct sysrq_key_op sysrq_xmon_op = { @@ -3318,7 +3321,7 @@ static int __init setup_xmon_sysrq(void) __initcall(setup_xmon_sysrq); #endif /* CONFIG_MAGIC_SYSRQ */ -static int __initdata xmon_early, xmon_off; +static int __initdata xmon_early; static int __init early_parse_xmon(char *p) { @@ -3326,10 +3329,12 @@ static int __init early_parse_xmon(char *p) /* just "xmon" is equivalent to "xmon=early" */ xmon_init(1); xmon_early = 1; - } else if (strncmp(p, "on", 2) == 0) + xmon_on = 1; + } else if (strncmp(p, "on", 2) == 0) { xmon_init(1); - else if (strncmp(p, "off", 3) == 0) - xmon_off = 1; + xmon_on = 1; + } else if (strncmp(p, "off", 3) == 0) + xmon_on = 0; else if (strncmp(p, "nobt", 4) == 0) xmon_no_auto_backtrace = 1; else @@ -3341,10 +3346,8 @@ early_param("xmon", early_parse_xmon); void __init xmon_setup(void) { -#ifdef CONFIG_XMON_DEFAULT - if (!xmon_off) + if (xmon_on) xmon_init(1); -#endif if (xmon_early) debugger(NULL); } -- 2.11.0