linux-kernel - [patch V4 14/41] x86/apic: Use BAD

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Message-ID: <20230814085112.862835121@linutronix.de>
Date:   Mon, 14 Aug 2023 10:53:56 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, Tom Lendacky <thomas.lendacky@....com>,
        Andrew Cooper <andrew.cooper3@...rix.com>,
        Arjan van de Ven <arjan@...ux.intel.com>,
        Huang Rui <ray.huang@....com>, Juergen Gross <jgross@...e.com>,
        Dimitri Sivanich <dimitri.sivanich@....com>,
        Michael Kelley <mikelley@...rosoft.com>,
        Wei Liu <wei.liu@...nel.org>, Pu Wen <puwen@...on.cn>,
        Qiuxu Zhuo <qiuxu.zhuo@...el.com>,
        Sohil Mehta <sohil.mehta@...el.com>
Subject: [patch V4 14/41] x86/apic: Use BAD_APICID consistently

APIC ID checks compare with BAD_APICID all over the place, but some
initializers and some code which fiddles with global data structure use
-1[U] instead. That simply cannot work at all.

Fix it up and use BAD_APICID consistently all over the place.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Tested-by: Juergen Gross <jgross@...e.com>
Tested-by: Sohil Mehta <sohil.mehta@...el.com>
Tested-by: Michael Kelley <mikelley@...rosoft.com>

---
V3: Fixed changelog typos - Sohil
---
 arch/x86/kernel/acpi/boot.c |    2 +-
 arch/x86/kernel/apic/apic.c |    6 ++----
 2 files changed, 3 insertions(+), 5 deletions(-)

--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -852,7 +852,7 @@ int acpi_unmap_cpu(int cpu)
 	set_apicid_to_node(per_cpu(x86_cpu_to_apicid, cpu), NUMA_NO_NODE);
 #endif
 
-	per_cpu(x86_cpu_to_apicid, cpu) = -1;
+	per_cpu(x86_cpu_to_apicid, cpu) = BAD_APICID;
 	set_cpu_present(cpu, false);
 	num_processors--;
 
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -72,7 +72,7 @@ unsigned int num_processors;
 unsigned disabled_cpus;
 
 /* Processor that is doing the boot up */
-unsigned int boot_cpu_physical_apicid __ro_after_init = -1U;
+unsigned int boot_cpu_physical_apicid __ro_after_init = BAD_APICID;
 EXPORT_SYMBOL_GPL(boot_cpu_physical_apicid);
 
 u8 boot_cpu_apic_version __ro_after_init;
@@ -2318,9 +2318,7 @@ static int nr_logical_cpuids = 1;
 /*
  * Used to store mapping between logical CPU IDs and APIC IDs.
  */
-int cpuid_to_apicid[] = {
-	[0 ... NR_CPUS - 1] = -1,
-};
+int cpuid_to_apicid[] = { [0 ... NR_CPUS - 1] = BAD_APICID, };
 
 bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
 {