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

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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: Li Zhong <zhong@linux.vnet.ibm.com>

=======================
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Li Zhong 2012-10-17 21:30:13 +00:00 committed by Benjamin Herrenschmidt
parent 323a6bf1d6
commit fb9125680d
2 changed files with 16 additions and 0 deletions
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8
arch/powerpc/platforms/pseries/hotplug-cpu.c
View file

@ -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()

8
arch/powerpc/platforms/pseries/plpar_wrappers.h
View file

@ -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;