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authorNicholas Piggin <npiggin@gmail.com>2019-10-22 21:58:14 +1000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-11-06 13:06:30 +0100
commit8f5603029223a169ab2e73334a3bcaa7b2c3a60b (patch)
treef025d3cd3311e4943695bd371f9e3c378606ed16
parent92930e9223994a4e26e9743e4131ad78d3f27ef0 (diff)
powerpc/powernv: Fix CPU idle to be called with IRQs disabled
[ Upstream commit 7d6475051fb3d9339c5c760ed9883bc0a9048b21 ] Commit e78a7614f3876 ("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 2525db04d1cc5 ("powerpc/powernv: Simplify lazy IRQ handling in CPU offline"). Fixes: e78a7614f3876 ("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 Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--arch/powerpc/platforms/powernv/smp.c53
1 files changed, 37 insertions, 16 deletions
diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c
index db09c7022635..fdd9577d1798 100644
--- a/arch/powerpc/platforms/powernv/smp.c
+++ b/arch/powerpc/platforms/powernv/smp.c
@@ -150,20 +150,25 @@ 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 */
@@ -177,6 +182,27 @@ static void pnv_smp_cpu_kill_self(void)
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
* LPCR_PECE_HVEE on P9) enabled so as to let IPIs in.
@@ -201,6 +227,7 @@ static void pnv_smp_cpu_kill_self(void)
srr1 = pnv_cpu_offline(cpu);
+ WARN_ON_ONCE(!irqs_disabled());
WARN_ON(lazy_irq_pending());
/*
@@ -216,13 +243,7 @@ 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));
@@ -270,7 +291,7 @@ 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);
}