x86, ioapic: Teach mp_register_ioapic to compute a global gsi_end

Add the global variable gsi_end and teach mp_register_ioapic
to keep it uptodate as we add more ioapics into the system.

ioapics can only be added early in boot so the code that
runs later can treat gsi_end as a constant.

Remove the have hacks in sfi.c to second guess mp_register_ioapic
by keeping t's own running total of how many gsi's have been seen,
and instead use the gsi_end.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <1269936436-7039-9-git-send-email-ebiederm@xmission.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 9ab97622b8e..f8072557157 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -89,6 +89,9 @@ int nr_ioapics;
 /* IO APIC gsi routing info */
 struct mp_ioapic_gsi  mp_gsi_routing[MAX_IO_APICS];
 
+/* The last gsi number used */
+u32 gsi_end;
+
 /* MP IRQ source entries */
 struct mpc_intsrc mp_irqs[MAX_IRQ_SOURCES];
 
@@ -4312,6 +4315,9 @@ void __init mp_register_ioapic(int id, u32 address, u32 gsi_base)
         mp_gsi_routing[idx].gsi_end = gsi_base +
             io_apic_get_redir_entries(idx) - 1;
 
+        if (mp_gsi_routing[idx].gsi_end > gsi_end)
+                gsi_end = mp_gsi_routing[idx].gsi_end;
+
         printk(KERN_INFO "IOAPIC[%d]: apic_id %d, version %d, address 0x%x, "
                "GSI %d-%d\n", idx, mp_ioapics[idx].apicid,
                mp_ioapics[idx].apicver, mp_ioapics[idx].apicaddr,