x86, ioapic: Fix non atomic allocation with interrupts disabled

Impact: fix possible race

save_mask_IO_APIC_setup() was using non atomic memory allocation while getting
called with interrupts disabled. Fix this by splitting this into two different
function. Allocation part save_IO_APIC_setup() now happens before
disabling interrupts.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 699f8cf76bbb..85eb8e100818 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1334,15 +1334,16 @@ void __init enable_IR_x2apic(void)
                 return;
         }
 
-        local_irq_save(flags);
-        mask_8259A();
-
-        ret = save_mask_IO_APIC_setup();
+        ret = save_IO_APIC_setup();
         if (ret) {
                 pr_info("Saving IO-APIC state failed: %d\n", ret);
                 goto end;
         }
 
+        local_irq_save(flags);
+        mask_IO_APIC_setup();
+        mask_8259A();
+
         ret = enable_intr_remapping(1);
 
         if (ret && x2apic_preenabled) {
@@ -1367,10 +1368,10 @@ end_restore:
         else
                 reinit_intr_remapped_IO_APIC(x2apic_preenabled);
 
-end:
         unmask_8259A();
         local_irq_restore(flags);
 
+end:
         if (!ret) {
                 if (!x2apic_preenabled)
                         pr_info("Enabled x2apic and interrupt-remapping\n");