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powerpc/powernv: Fix CPU idle to be called with IRQs disabled

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Commit e78a7614f3 ("idle: Prevent late-arriving interrupts from
disrupting offline") changes arch_cpu_idle_dead to be called with
interrupts disabled, which triggers the WARN in pnv_smp_cpu_kill_self.

Fix this by fixing up irq_happened after hard disabling, rather than
requiring there are no pending interrupts, similarly to what was done
done until commit 2525db04d1 ("powerpc/powernv: Simplify lazy IRQ
handling in CPU offline").

Fixes: e78a7614f3 ("idle: Prevent late-arriving interrupts from disrupting offline")
Reported-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Add unexpected_mask rather than checking for known bad values,
      change the WARN_ON() to a WARN_ON_ONCE()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191022115814.22456-1-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2019-10-22 21:58:14 +10:00 committed by Michael Ellerman
parent 05d9a95283
commit 7d6475051f
1 changed files with 37 additions and 16 deletions
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53
arch/powerpc/platforms/powernv/smp.c
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@ -146,20 +146,25 @@ static int pnv_smp_cpu_disable(void)
return 0;
}
static void pnv_flush_interrupts(void)
{
if (cpu_has_feature(CPU_FTR_ARCH_300)) {
if (xive_enabled())
xive_flush_interrupt();
else
icp_opal_flush_interrupt();
} else {
icp_native_flush_interrupt();
}
}
static void pnv_smp_cpu_kill_self(void)
{
unsigned long srr1, unexpected_mask, wmask;
unsigned int cpu;
unsigned long srr1, wmask;
u64 lpcr_val;
/* Standard hot unplug procedure */
/*
* This hard disables local interurpts, ensuring we have no lazy
* irqs pending.
*/
WARN_ON(irqs_disabled());
hard_irq_disable();
WARN_ON(lazy_irq_pending());
idle_task_exit();
current->active_mm = NULL; /* for sanity */
@ -172,6 +177,27 @@ static void pnv_smp_cpu_kill_self(void)
if (cpu_has_feature(CPU_FTR_ARCH_207S))
wmask = SRR1_WAKEMASK_P8;
/*
* This turns the irq soft-disabled state we're called with, into a
* hard-disabled state with pending irq_happened interrupts cleared.
*
* PACA_IRQ_DEC - Decrementer should be ignored.
* PACA_IRQ_HMI - Can be ignored, processing is done in real mode.
* PACA_IRQ_DBELL, EE, PMI - Unexpected.
*/
hard_irq_disable();
if (generic_check_cpu_restart(cpu))
goto out;
unexpected_mask = ~(PACA_IRQ_DEC | PACA_IRQ_HMI | PACA_IRQ_HARD_DIS);
if (local_paca->irq_happened & unexpected_mask) {
if (local_paca->irq_happened & PACA_IRQ_EE)
pnv_flush_interrupts();
DBG("CPU%d Unexpected exit while offline irq_happened=%lx!\n",
cpu, local_paca->irq_happened);
}
local_paca->irq_happened = PACA_IRQ_HARD_DIS;
/*
* We don't want to take decrementer interrupts while we are
* offline, so clear LPCR:PECE1. We keep PECE2 (and
@ -197,6 +223,7 @@ static void pnv_smp_cpu_kill_self(void)
srr1 = pnv_cpu_offline(cpu);
WARN_ON_ONCE(!irqs_disabled());
WARN_ON(lazy_irq_pending());
/*
@ -212,13 +239,7 @@ static void pnv_smp_cpu_kill_self(void)
*/
if (((srr1 & wmask) == SRR1_WAKEEE) ||
((srr1 & wmask) == SRR1_WAKEHVI)) {
if (cpu_has_feature(CPU_FTR_ARCH_300)) {
if (xive_enabled())
xive_flush_interrupt();
else
icp_opal_flush_interrupt();
} else
icp_native_flush_interrupt();
pnv_flush_interrupts();
} else if ((srr1 & wmask) == SRR1_WAKEHDBELL) {
unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER);
asm volatile(PPC_MSGCLR(%0) : : "r" (msg));
@ -266,7 +287,7 @@ static void pnv_smp_cpu_kill_self(void)
*/
lpcr_val = mfspr(SPRN_LPCR) | (u64)LPCR_PECE1;
pnv_program_cpu_hotplug_lpcr(cpu, lpcr_val);
out:
DBG("CPU%d coming online...\n", cpu);
}