Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit fb912568 authored by Li Zhong's avatar Li Zhong Committed by Benjamin Herrenschmidt
Browse files

powerpc: Fix a lazy irq related WARING in arch_local_irq_restore() 



The pseries CPU hotplug code uses cede_processor without properly
synchronizing the SW and HW interrupt enable state. This fixes
it using the same helpers that were written for the idle code.

Signed-off-by: default avatarLi Zhong <zhong@linux.vnet.ibm.com>

=======================
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 323a6bf1

arch/powerpc/platforms/pseries/hotplug-cpu.c

+8 −0
Original line number Diff line number Diff line
@@ -127,9 +127,16 @@ static void pseries_mach_cpu_die(void) 
			get_lppaca()->donate_dedicated_cpu = 1;



		while (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) {

			while (!prep_irq_for_idle()) {

				local_irq_enable();

				local_irq_disable();

			}



			extended_cede_processor(cede_latency_hint);

		}



		local_irq_disable();



		if (!get_lppaca()->shared_proc)

			get_lppaca()->donate_dedicated_cpu = 0;

		get_lppaca()->idle = 0;
@@ -137,6 +144,7 @@ static void pseries_mach_cpu_die(void) 
		if (get_preferred_offline_state(cpu) == CPU_STATE_ONLINE) {

			unregister_slb_shadow(hwcpu);



			hard_irq_disable();

			/*

			 * Call to start_secondary_resume() will not return.

			 * Kernel stack will be reset and start_secondary()

arch/powerpc/platforms/pseries/plpar_wrappers.h

+8 −0
Original line number Diff line number Diff line
@@ -2,6 +2,7 @@ 
#define _PSERIES_PLPAR_WRAPPERS_H



#include <linux/string.h>

#include <linux/irqflags.h>



#include <asm/hvcall.h>

#include <asm/paca.h>
@@ -41,7 +42,14 @@ static inline long extended_cede_processor(unsigned long latency_hint) 
	u8 old_latency_hint = get_cede_latency_hint();



	set_cede_latency_hint(latency_hint);



	rc = cede_processor();

#ifdef CONFIG_TRACE_IRQFLAGS

		/* Ensure that H_CEDE returns with IRQs on */

		if (WARN_ON(!(mfmsr() & MSR_EE)))

			__hard_irq_enable();

#endif



	set_cede_latency_hint(old_latency_hint);



	return rc;