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Message-ID: <20230724132045.302673759@linutronix.de>
From:   Thomas Gleixner <tglx@linutronix.de>
To:     LKML <linux-kernel@vger.kernel.org>
Cc:     x86@kernel.org, Andrew Cooper <andrew.cooper3@citrix.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Wei Liu <wei.liu@kernel.org>,
        Arjan van de Ven <arjan@linux.intel.com>,
        Juergen Gross <jgross@suse.com>,
        Michael Kelley <mikelley@microsoft.com>,
        Peter Keresztes Schmidt <peter@keresztesschmidt.de>,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>
Subject: [patch V2 12/58] x86/of: Fix the APIC address registration
References: <20230724131206.500814398@linutronix.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Date:   Mon, 24 Jul 2023 15:34:04 +0200 (CEST)
Precedence: bulk

The device tree APIC parser tries to force enable the local APIC when it is
not set in CPUID. apic_force_enable() registers the boot CPU apic on
success.

If that succeeds then dtb_lapic_setup() registers the local APIC again
eventually with a different address.

Rewrite the code so that it only registers it once.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/x86/kernel/devicetree.c |   14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

--- a/arch/x86/kernel/devicetree.c
+++ b/arch/x86/kernel/devicetree.c
@@ -157,19 +157,15 @@ static void __init dtb_lapic_setup(void)
 
 	/* Did the boot loader setup the local APIC ? */
 	if (!boot_cpu_has(X86_FEATURE_APIC)) {
+		/* Try force enabling, which registers the APIC address */
 		if (apic_force_enable(lapic_addr))
 			return;
-	}
-	smp_found_config = 1;
-	if (of_property_read_bool(dn, "intel,virtual-wire-mode")) {
-		pr_info("Virtual Wire compatibility mode.\n");
-		pic_mode = 0;
 	} else {
-		pr_info("IMCR and PIC compatibility mode.\n");
-		pic_mode = 1;
+		register_lapic_address(lapic_addr);
 	}
-
-	register_lapic_address(lapic_addr);
+	smp_found_config = 1;
+	pic_mode = !of_property_read_bool(dn, "intel,virtual-wire-mode");
+	pr_info("%s compatibility mode.\n", pic_mode ? "IMCR and PIC" : "Virtual Wire");
 }
 
 #endif /* CONFIG_X86_LOCAL_APIC */