Use memory barriers to protect searching side code when hot-plugging
IOAPICs.
Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
---
arch/x86/kernel/apic/io_apic.c | 25 ++++++++++++++++++-------
1 files changed, 18 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 9c2ac7b..49c016a 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -352,12 +352,15 @@ static void free_ioapic_gsi_irq_base(int idx)
static void alloc_ioapic_saved_registers(int idx)
{
+ struct mp_ioapic_gsi *gsi_cfg = mp_ioapic_gsi_routing(idx);
+ int irq_cnt = gsi_cfg->gsi_end - gsi_cfg->gsi_base + 1;
+
if (ioapics[idx].saved_registers)
return;
ioapics[idx].saved_registers =
kzalloc(sizeof(struct IO_APIC_route_entry) *
- ioapics[idx].nr_registers, GFP_KERNEL);
+ irq_cnt, GFP_KERNEL);
if (!ioapics[idx].saved_registers)
pr_err("IOAPIC %d: suspend/resume impossible!\n", idx);
@@ -1174,6 +1177,8 @@ int IO_APIC_get_PCI_irq_vector(int bus, int slot, int pin,
for (ioapic_idx = 0; ioapic_idx < nr_ioapics; ioapic_idx++) {
if (!ioapics[ioapic_idx].nr_registers)
continue;
+
+ smp_rmb();
if (mpc_ioapic_id(ioapic_idx) == mp_irqs[i].dstapic ||
mp_irqs[i].dstapic == MP_APIC_ALL)
break;
@@ -2083,7 +2088,7 @@ void __init enable_IO_APIC(void)
if (!legacy_pic->nr_legacy_irqs)
return;
- for(apic = 0; apic < nr_ioapics; apic++) {
+ for (apic = 0; apic < nr_ioapics; apic++) {
int pin;
/* See if any of the pins is in ExtINT mode */
for (pin = 0; pin < ioapics[apic].nr_registers; pin++) {
@@ -4134,6 +4139,7 @@ int mp_find_ioapic(u32 gsi)
if (!ioapics[i].nr_registers)
continue;
+ smp_rmb();
if ((gsi >= gsi_cfg->gsi_base) && (gsi <= gsi_cfg->gsi_end))
return i;
}
@@ -4214,11 +4220,6 @@ int __mp_register_ioapic(int id, u32 address, u32 gsi_base, bool hotadd)
gsi_cfg->gsi_base = gsi_base;
gsi_cfg->gsi_end = gsi_base + entries - 1;
- /*
- * The number of IO-APIC IRQ registers (== #pins):
- */
- ioapics[idx].nr_registers = entries;
-
if (!hotadd) {
/*
* irqs will be reserved in arch_early_irq_init()
@@ -4247,6 +4248,13 @@ int __mp_register_ioapic(int id, u32 address, u32 gsi_base, bool hotadd)
if (idx == nr_ioapics)
nr_ioapics++;
+ smp_wmb();
+
+ /*
+ * The number of IO-APIC IRQ registers (== #pins):
+ */
+ ioapics[idx].nr_registers = entries;
+
return 0;
failed:
@@ -4270,6 +4278,9 @@ int mp_unregister_ioapic(u32 gsi_base)
if (idx < 0)
return -EINVAL;
+ ioapics[idx].nr_registers = 0;
+ smp_wmb();
+
free_ioapic_saved_registers(idx);
free_ioapic_gsi_irq_base(idx);
--
1.7.5.4
--
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