From: Sebastian Andrzej Siewior <bige...@linutronix.de>
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 <bige...@linutronix.de>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Acked-by: Mark Rutland <mark.rutl...@arm.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Will Deacon <will.dea...@arm.com>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Russell King <li...@armlinux.org.uk>
Cc: linux-arm-ker...@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();
