x86, irq, ACPI: Introduce a mutex to protect IOAPIC operations from hotplug
We are going to support ACPI based IOAPIC hotplug, so introduce a mutex
to protect IOAPIC data structures from IOAPIC hotplug. We choose to
serialize in ACPI instead of in the IOAPIC core because:
1) currently we only plan to support ACPI based IOAPIC hotplug
2) it's much more cleaner and easier
3) It does't affect IOAPIC discovered by devicetree, SFI and mpparse.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Link: http://lkml.kernel.org/r/1414908273-7552-15-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 6ddeba31..2d76f02 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -76,6 +76,19 @@
static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE;
#endif
+/*
+ * Locks related to IOAPIC hotplug
+ * Hotplug side:
+ * ->device_hotplug_lock
+ * ->acpi_ioapic_lock
+ * ->ioapic_lock
+ * Interrupt mapping side:
+ * ->acpi_ioapic_lock
+ * ->ioapic_mutex
+ * ->ioapic_lock
+ */
+static DEFINE_MUTEX(acpi_ioapic_lock);
+
/* --------------------------------------------------------------------------
Boot-time Configuration
-------------------------------------------------------------------------- */
@@ -609,8 +622,10 @@
if (acpi_irq_model == ACPI_IRQ_MODEL_PIC) {
*irqp = gsi;
} else {
+ mutex_lock(&acpi_ioapic_lock);
irq = mp_map_gsi_to_irq(gsi,
IOAPIC_MAP_ALLOC | IOAPIC_MAP_CHECK);
+ mutex_unlock(&acpi_ioapic_lock);
if (irq < 0)
return -1;
*irqp = irq;
@@ -650,7 +665,9 @@
int irq = gsi;
#ifdef CONFIG_X86_IO_APIC
+ mutex_lock(&acpi_ioapic_lock);
irq = mp_register_gsi(dev, gsi, trigger, polarity);
+ mutex_unlock(&acpi_ioapic_lock);
#endif
return irq;
@@ -659,7 +676,9 @@
static void acpi_unregister_gsi_ioapic(u32 gsi)
{
#ifdef CONFIG_X86_IO_APIC
+ mutex_lock(&acpi_ioapic_lock);
mp_unregister_gsi(gsi);
+ mutex_unlock(&acpi_ioapic_lock);
#endif
}
@@ -1187,7 +1206,9 @@
/*
* Parse MADT IO-APIC entries
*/
+ mutex_lock(&acpi_ioapic_lock);
error = acpi_parse_madt_ioapic_entries();
+ mutex_unlock(&acpi_ioapic_lock);
if (!error) {
acpi_set_irq_model_ioapic();