[patch V2 05/22] x86/ioapic: Make io_apic_get_unique_id() simpler

From: Thomas Gleixner
Date: Tue Jan 23 2024 - 08:11:19 EST


From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

No need to go through APIC callbacks. It's already established that this is
an ancient APIC. So just copy the present mask and use the direct physid*
functions all over the place.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

---
arch/x86/kernel/apic/io_apic.c | 22 +++++-----------------
1 file changed, 5 insertions(+), 17 deletions(-)
---
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -2498,17 +2498,9 @@ static int io_apic_get_unique_id(int ioa
unsigned long flags;
int i = 0;

- /*
- * The P4 platform supports up to 256 APIC IDs on two separate APIC
- * buses (one for LAPICs, one for IOAPICs), where predecessors only
- * supports up to 16 on one shared APIC bus.
- *
- * TBD: Expand LAPIC/IOAPIC support on P4-class systems to take full
- * advantage of new APIC bus architecture.
- */
-
+ /* Initialize the ID map */
if (physids_empty(apic_id_map))
- apic->ioapic_phys_id_map(&phys_cpu_present_map, &apic_id_map);
+ apic_id_map = phys_cpu_present_map;

raw_spin_lock_irqsave(&ioapic_lock, flags);
reg_00.raw = io_apic_read(ioapic, 0);
@@ -2520,14 +2512,10 @@ static int io_apic_get_unique_id(int ioa
apic_id = reg_00.bits.ID;
}

- /*
- * Every APIC in a system must have a unique ID or we get lots of nice
- * 'stuck on smp_invalidate_needed IPI wait' messages.
- */
- if (apic->check_apicid_used(&apic_id_map, apic_id)) {
-
+ /* Every APIC in a system must have a unique ID */
+ if (physid_isset(apic_id, apic_id_map)) {
for (i = 0; i < broadcast_id; i++) {
- if (!apic->check_apicid_used(&apic_id_map, i))
+ if (!physid_isset(i, apic_id_map))
break;
}