| From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| Date: Wed, 24 May 2017 10:15:25 +0200 |
| Subject: [PATCH 14/32] ARM/hw_breakpoint: Use cpuhp_setup_state_cpuslocked() |
| |
| 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 <bigeasy@linutronix.de> |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| Acked-by: Ingo Molnar <mingo@kernel.org> |
| Acked-by: Mark Rutland <mark.rutland@arm.com> |
| Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> |
| Cc: Peter Zijlstra <peterz@infradead.org> |
| Cc: Will Deacon <will.deacon@arm.com> |
| Cc: Steven Rostedt <rostedt@goodmis.org> |
| Cc: Russell King <linux@armlinux.org.uk> |
| Cc: linux-arm-kernel@lists.infradead.org |
| Link: http://lkml.kernel.org/r/20170524081548.170940729@linutronix.de |
| --- |
| 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(); |