x64, x2apic/intr-remap: ioapic routines which deal with initial io-apic RTE setup

Generic ioapic specific routines which be used later during enabling
interrupt-remapping.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 66 insertions, 0 deletions

diff --git a/arch/x86/kernel/io_apic_64.c b/arch/x86/kernel/io_apic_64.c
index 9e645cba11c4..84dd63c13d63 100644
--- a/arch/x86/kernel/io_apic_64.c
+++ b/arch/x86/kernel/io_apic_64.c
@@ -114,6 +114,9 @@ DEFINE_SPINLOCK(vector_lock);
  */
 int nr_ioapic_registers[MAX_IO_APICS];
 
+/* I/O APIC RTE contents at the OS boot up */
+struct IO_APIC_route_entry *early_ioapic_entries[MAX_IO_APICS];
+
 /* I/O APIC entries */
 struct mp_config_ioapic mp_ioapics[MAX_IO_APICS];
 int nr_ioapics;
@@ -446,6 +449,69 @@ static void clear_IO_APIC (void)
                         clear_IO_APIC_pin(apic, pin);
 }
 
+/*
+ * Saves and masks all the unmasked IO-APIC RTE's
+ */
+int save_mask_IO_APIC_setup(void)
+{
+        union IO_APIC_reg_01 reg_01;
+        unsigned long flags;
+        int apic, pin;
+
+        /*
+         * The number of IO-APIC IRQ registers (== #pins):
+         */
+        for (apic = 0; apic < nr_ioapics; apic++) {
+                spin_lock_irqsave(&ioapic_lock, flags);
+                reg_01.raw = io_apic_read(apic, 1);
+                spin_unlock_irqrestore(&ioapic_lock, flags);
+                nr_ioapic_registers[apic] = reg_01.bits.entries+1;
+        }
+
+        for (apic = 0; apic < nr_ioapics; apic++) {
+                early_ioapic_entries[apic] =
+                        kzalloc(sizeof(struct IO_APIC_route_entry) *
+                                nr_ioapic_registers[apic], GFP_KERNEL);
+                if (!early_ioapic_entries[apic])
+                        return -ENOMEM;
+        }
+
+        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] =
+                                ioapic_read_entry(apic, pin);
+                        if (!entry.mask) {
+                                entry.mask = 1;
+                                ioapic_write_entry(apic, pin, entry);
+                        }
+                }
+        return 0;
+}
+
+void restore_IO_APIC_setup(void)
+{
+        int apic, pin;
+
+        for (apic = 0; apic < nr_ioapics; apic++)
+                for (pin = 0; pin < nr_ioapic_registers[apic]; pin++)
+                        ioapic_write_entry(apic, pin,
+                                           early_ioapic_entries[apic][pin]);
+}
+
+void reinit_intr_remapped_IO_APIC(int intr_remapping)
+{
+        /*
+         * for now plain restore of previous settings.
+         * TBD: In the case of OS enabling interrupt-remapping,
+         * IO-APIC RTE's need to be setup to point to interrupt-remapping
+         * table entries. for now, do a plain restore, and wait for
+         * the setup_IO_APIC_irqs() to do proper initialization.
+         */
+        restore_IO_APIC_setup();
+}
+
 int skip_ioapic_setup;
 int ioapic_force;