From mboxrd@z Thu Jan 1 00:00:00 1970 From: tglx@linutronix.de (Thomas Gleixner) Date: Wed, 24 May 2017 10:15:25 +0200 Subject: [patch V3 14/32] ARM/hw_breakpoint: Use cpuhp_setup_state_cpuslocked() References: <20170524081511.203800767@linutronix.de> Message-ID: <20170524081548.170940729@linutronix.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Sebastian Andrzej Siewior arch_hw_breakpoint_init() holds get_online_cpus() while registerring the hotplug callbacks. cpuhp_setup_state() invokes get_online_cpus() as well. This is correct, but prevents the conversion of the hotplug locking to a percpu rwsem. Use cpuhp_setup_state_cpuslocked() to avoid the nested call. Convert *_online_cpus() to the new interfaces while at it. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Acked-by: Mark Rutland Cc: Peter Zijlstra Cc: Will Deacon Cc: Steven Rostedt Cc: Russell King Cc: linux-arm-kernel at lists.infradead.org --- arch/arm/kernel/hw_breakpoint.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) --- a/arch/arm/kernel/hw_breakpoint.c +++ b/arch/arm/kernel/hw_breakpoint.c @@ -1090,7 +1090,7 @@ static int __init arch_hw_breakpoint_ini * driven low on this core and there isn't an architected way to * determine that. */ - get_online_cpus(); + cpus_read_lock(); register_undef_hook(&debug_reg_hook); /* @@ -1098,15 +1098,16 @@ static int __init arch_hw_breakpoint_ini * assume that a halting debugger will leave the world in a nice state * for us. */ - ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "arm/hw_breakpoint:online", - dbg_reset_online, NULL); + ret = cpuhp_setup_state_cpuslocked(CPUHP_AP_ONLINE_DYN, + "arm/hw_breakpoint:online", + dbg_reset_online, NULL); unregister_undef_hook(&debug_reg_hook); if (WARN_ON(ret < 0) || !cpumask_empty(&debug_err_mask)) { core_num_brps = 0; core_num_wrps = 0; if (ret > 0) cpuhp_remove_state_nocalls(ret); - put_online_cpus(); + cpus_read_unlock(); return 0; } @@ -1124,7 +1125,7 @@ static int __init arch_hw_breakpoint_ini TRAP_HWBKPT, "watchpoint debug exception"); hook_ifault_code(FAULT_CODE_DEBUG, hw_breakpoint_pending, SIGTRAP, TRAP_HWBKPT, "breakpoint debug exception"); - put_online_cpus(); + cpus_read_unlock(); /* Register PM notifiers. */ pm_init(); From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765612AbdEXI02 (ORCPT ); Wed, 24 May 2017 04:26:28 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:57975 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1764984AbdEXI0W (ORCPT ); Wed, 24 May 2017 04:26:22 -0400 Message-Id: <20170524081548.170940729@linutronix.de> User-Agent: quilt/0.63-1 Date: Wed, 24 May 2017 10:15:25 +0200 From: Thomas Gleixner To: LKML Cc: Peter Zijlstra , Ingo Molnar , Steven Rostedt , Sebastian Siewior , Paul McKenney , Mark Rutland , Will Deacon , Russell King , linux-arm-kernel@lists.infradead.org Subject: [patch V3 14/32] ARM/hw_breakpoint: Use cpuhp_setup_state_cpuslocked() References: <20170524081511.203800767@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=ARMhw_breakpoint_Use_cpuhp_setup_state_cpuslocked().patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sebastian Andrzej Siewior arch_hw_breakpoint_init() holds get_online_cpus() while registerring the hotplug callbacks. cpuhp_setup_state() invokes get_online_cpus() as well. This is correct, but prevents the conversion of the hotplug locking to a percpu rwsem. Use cpuhp_setup_state_cpuslocked() to avoid the nested call. Convert *_online_cpus() to the new interfaces while at it. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Acked-by: Mark Rutland Cc: Peter Zijlstra Cc: Will Deacon Cc: Steven Rostedt Cc: Russell King Cc: linux-arm-kernel@lists.infradead.org --- arch/arm/kernel/hw_breakpoint.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) --- a/arch/arm/kernel/hw_breakpoint.c +++ b/arch/arm/kernel/hw_breakpoint.c @@ -1090,7 +1090,7 @@ static int __init arch_hw_breakpoint_ini * driven low on this core and there isn't an architected way to * determine that. */ - get_online_cpus(); + cpus_read_lock(); register_undef_hook(&debug_reg_hook); /* @@ -1098,15 +1098,16 @@ static int __init arch_hw_breakpoint_ini * assume that a halting debugger will leave the world in a nice state * for us. */ - ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "arm/hw_breakpoint:online", - dbg_reset_online, NULL); + ret = cpuhp_setup_state_cpuslocked(CPUHP_AP_ONLINE_DYN, + "arm/hw_breakpoint:online", + dbg_reset_online, NULL); unregister_undef_hook(&debug_reg_hook); if (WARN_ON(ret < 0) || !cpumask_empty(&debug_err_mask)) { core_num_brps = 0; core_num_wrps = 0; if (ret > 0) cpuhp_remove_state_nocalls(ret); - put_online_cpus(); + cpus_read_unlock(); return 0; } @@ -1124,7 +1125,7 @@ static int __init arch_hw_breakpoint_ini TRAP_HWBKPT, "watchpoint debug exception"); hook_ifault_code(FAULT_CODE_DEBUG, hw_breakpoint_pending, SIGTRAP, TRAP_HWBKPT, "breakpoint debug exception"); - put_online_cpus(); + cpus_read_unlock(); /* Register PM notifiers. */ pm_init();