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From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: x86@kernel.org,
 Tom Lendacky <thomas.lendacky@amd.com>,
 Andrew Cooper <andrew.cooper3@citrix.com>,
 Arjan van de Ven <arjan@linux.intel.com>,
 Huang Rui <ray.huang@amd.com>,
 Juergen Gross <jgross@suse.com>,
 Dimitri Sivanich <dimitri.sivanich@hpe.com>,
 Sohil Mehta <sohil.mehta@intel.com>,
 K Prateek Nayak <kprateek.nayak@amd.com>,
 Kan Liang <kan.liang@linux.intel.com>,
 Zhang Rui <rui.zhang@intel.com>,
 "Paul E. McKenney" <paulmck@kernel.org>,
 Feng Tang <feng.tang@intel.com>,
 Andy Shevchenko <andy@infradead.org>,
 Michael Kelley <mhklinux@outlook.com>,
 "Peter Zijlstra (Intel)" <peterz@infradead.org>
Subject: [patch v2 12/30] x86/smpboot: Make error message actually useful
References: <20240118123127.055361964@linutronix.de>
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Date: Tue, 23 Jan 2024 14:11:09 +0100 (CET)

From: Thomas Gleixner <tglx@linutronix.de>

"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@linutronix.de>

---
 arch/x86/kernel/smpboot.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)
---
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1072,9 +1072,13 @@ int native_kick_ap(unsigned int cpu, str
 
 	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;
 	}