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, 23 insertions, 11 deletions

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index cf27795c641..ff1759a1128 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -853,9 +853,9 @@ __setup("pirq=", ioapic_pirq_setup);
 static struct IO_APIC_route_entry *early_ioapic_entries[MAX_IO_APICS];
 
 /*
- * Saves and masks all the unmasked IO-APIC RTE's
+ * Saves all the IO-APIC RTE's
  */
-int save_mask_IO_APIC_setup(void)
+int save_IO_APIC_setup(void)
 {
         union IO_APIC_reg_01 reg_01;
         unsigned long flags;
@@ -880,16 +880,9 @@ int save_mask_IO_APIC_setup(void)
         }
 
         for (apic = 0; apic < nr_ioapics; apic++)
-                for (pin = 0; pin < nr_ioapic_registers[apic]; pin++) {
-                        struct IO_APIC_route_entry entry;
-
-                        entry = early_ioapic_entries[apic][pin] =
+                for (pin = 0; pin < nr_ioapic_registers[apic]; pin++)
+                        early_ioapic_entries[apic][pin] =
                                 ioapic_read_entry(apic, pin);
-                        if (!entry.mask) {
-                                entry.mask = 1;
-                                ioapic_write_entry(apic, pin, entry);
-                        }
-                }
 
         return 0;
 
@@ -902,6 +895,25 @@ nomem:
         return -ENOMEM;
 }
 
+void mask_IO_APIC_setup(void)
+{
+        int apic, pin;
+
+        for (apic = 0; apic < nr_ioapics; apic++) {
+                if (!early_ioapic_entries[apic])
+                        break;
+                for (pin = 0; pin < nr_ioapic_registers[apic]; pin++) {
+                        struct IO_APIC_route_entry entry;
+
+                        entry = early_ioapic_entries[apic][pin];
+                        if (!entry.mask) {
+                                entry.mask = 1;
+                                ioapic_write_entry(apic, pin, entry);
+                        }
+                }
+        }
+}
+
 void restore_IO_APIC_setup(void)
 {
         int apic, pin;