[tip: x86/apic] x86/ioapic: Make io_apic_get_unique_id() simpler

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the x86/apic branch of tip:

Commit-ID:     533535afc079b745ae8a5fd06afd2ba51b3495fe
Gitweb:        https://git.kernel.org/tip/533535afc079b745ae8a5fd06afd2ba51b3495fe
Author:        Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate:    Tue, 13 Feb 2024 22:04:57 +01:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Thu, 15 Feb 2024 22:07:39 +01:00

x86/ioapic: Make io_apic_get_unique_id() simpler

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>
Tested-by: Michael Kelley <mhklinux@xxxxxxxxxxx>
Tested-by: Sohil Mehta <sohil.mehta@xxxxxxxxx>
Link: https://lore.kernel.org/r/20240212154639.119261725@xxxxxxxxxxxxx



---
 arch/x86/kernel/apic/io_apic.c | 22 +++++-----------------
 1 file changed, 5 insertions(+), 17 deletions(-)

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index a4219b9..8dc91d0 100644
--- 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 ioapic, int apic_id)
 	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 ioapic, int apic_id)
 		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;
 		}