[tip: x86/apic] x86/smpboot: Make error message actually useful

[tip-bot2 for Thomas Gleixner]

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

Commit-ID:     6055f6cf0d462fa0d9212a8279b6b0d1130552e1
Gitweb:        https://git.kernel.org/tip/6055f6cf0d462fa0d9212a8279b6b0d1130552e1
Author:        Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate:    Tue, 13 Feb 2024 22:05:50 +01:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Thu, 15 Feb 2024 22:07:43 +01:00

x86/smpboot: Make error message actually useful

"smpboot: native_kick_ap: bad cpu 33" is absolutely useless information.

Replace it with something meaningful which allows to decode the failure
condition.

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/20240213210252.170806023@xxxxxxxxxxxxx



---
 arch/x86/kernel/smpboot.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index bfb99b5..d850fac 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1072,9 +1072,13 @@ int native_kick_ap(unsigned int cpu, struct task_struct *tidle)
 
 	pr_debug("++++++++++++++++++++=_---CPU UP  %u\n", cpu);
 
-	if (apicid == BAD_APICID || !test_bit(apicid, phys_cpu_present_map) ||
-	    !apic_id_valid(apicid)) {
-		pr_err("%s: bad cpu %d\n", __func__, cpu);
+	if (apicid == BAD_APICID || !apic_id_valid(apicid)) {
+		pr_err("CPU %u has invalid APIC ID %x. Aborting bringup\n", cpu, apicid);
+		return -EINVAL;
+	}
+
+	if (!test_bit(apicid, phys_cpu_present_map)) {
+		pr_err("CPU %u APIC ID %x is not present. Aborting bringup\n", cpu, apicid);
 		return -EINVAL;
 	}