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Date: Fri, 16 Feb 2024 15:16:59 -0000
From: "tip-bot2 for Thomas Gleixner" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Thomas Gleixner <tglx@...utronix.de>,
Michael Kelley <mhklinux@...look.com>, Sohil Mehta <sohil.mehta@...el.com>,
x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/apic] x86/cpu/topology: Sanitize the APIC admission logic
The following commit has been merged into the x86/apic branch of tip:
Commit-ID: 0e53e7b656cf5aa67c08eca381cec858478195a7
Gitweb: https://git.kernel.org/tip/0e53e7b656cf5aa67c08eca381cec858478195a7
Author: Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Tue, 13 Feb 2024 22:05:52 +01:00
Committer: Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Thu, 15 Feb 2024 22:07:43 +01:00
x86/cpu/topology: Sanitize the APIC admission logic
Move the actually required content of generic_processor_id() into the call
sites and use common helper functions for them. This separates the early
boot registration and the ACPI hotplug mechanism completely which allows
further cleanups and improvements.
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Tested-by: Michael Kelley <mhklinux@...look.com>
Tested-by: Sohil Mehta <sohil.mehta@...el.com>
Link: https://lore.kernel.org/r/20240213210252.230433953@linutronix.de
---
arch/x86/kernel/cpu/topology.c | 159 +++++++++++++++-----------------
1 file changed, 77 insertions(+), 82 deletions(-)
diff --git a/arch/x86/kernel/cpu/topology.c b/arch/x86/kernel/cpu/topology.c
index 815e3ee..80625f4 100644
--- a/arch/x86/kernel/cpu/topology.c
+++ b/arch/x86/kernel/cpu/topology.c
@@ -30,8 +30,10 @@ static struct {
unsigned int nr_assigned_cpus;
unsigned int nr_disabled_cpus;
unsigned int nr_rejected_cpus;
+ u32 boot_cpu_apic_id;
} topo_info __read_mostly = {
.nr_assigned_cpus = 1,
+ .boot_cpu_apic_id = BAD_APICID,
};
/*
@@ -83,78 +85,6 @@ early_initcall(smp_init_primary_thread_mask);
static inline void cpu_mark_primary_thread(unsigned int cpu, unsigned int apicid) { }
#endif
-static int topo_lookup_cpuid(u32 apic_id)
-{
- int i;
-
- /* CPU# to APICID mapping is persistent once it is established */
- for (i = 0; i < topo_info.nr_assigned_cpus; i++) {
- if (cpuid_to_apicid[i] == apic_id)
- return i;
- }
- return -ENODEV;
-}
-
-/*
- * Should use this API to allocate logical CPU IDs to keep nr_logical_cpuids
- * and cpuid_to_apicid[] synchronized.
- */
-static int allocate_logical_cpuid(u32 apic_id)
-{
- int cpu = topo_lookup_cpuid(apic_id);
-
- if (cpu >= 0)
- return cpu;
-
- return topo_info.nr_assigned_cpus++;
-}
-
-static void cpu_update_apic(unsigned int cpu, u32 apic_id)
-{
-#if defined(CONFIG_SMP) || defined(CONFIG_X86_64)
- early_per_cpu(x86_cpu_to_apicid, cpu) = apic_id;
-#endif
- cpuid_to_apicid[cpu] = apic_id;
- set_cpu_possible(cpu, true);
- set_bit(apic_id, phys_cpu_present_map);
- set_cpu_present(cpu, true);
-
- if (system_state != SYSTEM_BOOTING)
- cpu_mark_primary_thread(cpu, apic_id);
-}
-
-static int generic_processor_info(int apicid)
-{
- int cpu;
-
- /* The boot CPU must be set before MADT/MPTABLE parsing happens */
- if (cpuid_to_apicid[0] == BAD_APICID)
- panic("Boot CPU APIC not registered yet\n");
-
- if (apicid == boot_cpu_physical_apicid)
- return 0;
-
- if (disabled_cpu_apicid == apicid) {
- int thiscpu = topo_info.nr_assigned_cpus + topo_info.nr_disabled_cpus;
-
- pr_warn("APIC: Disabling requested cpu. Processor %d/0x%x ignored.\n",
- thiscpu, apicid);
-
- topo_info.nr_rejected_cpus++;
- return -ENODEV;
- }
-
- if (topo_info.nr_assigned_cpus >= nr_cpu_ids) {
- pr_warn_once("APIC: CPU limit of %d reached. Ignoring further CPUs\n", nr_cpu_ids);
- topo_info.nr_rejected_cpus++;
- return -ENOSPC;
- }
-
- cpu = allocate_logical_cpuid(apicid);
- cpu_update_apic(cpu, apicid);
- return cpu;
-}
-
static int __initdata setup_possible_cpus = -1;
/*
@@ -222,6 +152,43 @@ __init void prefill_possible_map(void)
set_cpu_possible(i, true);
}
+static int topo_lookup_cpuid(u32 apic_id)
+{
+ int i;
+
+ /* CPU# to APICID mapping is persistent once it is established */
+ for (i = 0; i < topo_info.nr_assigned_cpus; i++) {
+ if (cpuid_to_apicid[i] == apic_id)
+ return i;
+ }
+ return -ENODEV;
+}
+
+static int topo_get_cpunr(u32 apic_id)
+{
+ int cpu = topo_lookup_cpuid(apic_id);
+
+ if (cpu >= 0)
+ return cpu;
+
+ return topo_info.nr_assigned_cpus++;
+}
+
+static void topo_set_cpuids(unsigned int cpu, u32 apic_id, u32 acpi_id)
+{
+#if defined(CONFIG_SMP) || defined(CONFIG_X86_64)
+ early_per_cpu(x86_cpu_to_apicid, cpu) = apic_id;
+ early_per_cpu(x86_cpu_to_acpiid, cpu) = acpi_id;
+#endif
+ cpuid_to_apicid[cpu] = apic_id;
+
+ set_cpu_possible(cpu, true);
+ set_cpu_present(cpu, true);
+
+ if (system_state != SYSTEM_BOOTING)
+ cpu_mark_primary_thread(cpu, apic_id);
+}
+
/**
* topology_register_apic - Register an APIC in early topology maps
* @apic_id: The APIC ID to set up
@@ -234,17 +201,40 @@ void __init topology_register_apic(u32 apic_id, u32 acpi_id, bool present)
if (apic_id >= MAX_LOCAL_APIC) {
pr_err_once("APIC ID %x exceeds kernel limit of: %x\n", apic_id, MAX_LOCAL_APIC - 1);
+ topo_info.nr_rejected_cpus++;
return;
}
- if (!present) {
- topo_info.nr_disabled_cpus++;
+ if (disabled_cpu_apicid == apic_id) {
+ pr_info("Disabling CPU as requested via 'disable_cpu_apicid=0x%x'.\n", apic_id);
+ topo_info.nr_rejected_cpus++;
return;
}
- cpu = generic_processor_info(apic_id);
- if (cpu >= 0)
- early_per_cpu(x86_cpu_to_acpiid, cpu) = acpi_id;
+ /* CPU numbers exhausted? */
+ if (apic_id != topo_info.boot_cpu_apic_id && topo_info.nr_assigned_cpus >= nr_cpu_ids) {
+ pr_warn_once("CPU limit of %d reached. Ignoring further CPUs\n", nr_cpu_ids);
+ topo_info.nr_rejected_cpus++;
+ return;
+ }
+
+ if (present) {
+ set_bit(apic_id, phys_cpu_present_map);
+
+ /*
+ * Double registration is valid in case of the boot CPU
+ * APIC because that is registered before the enumeration
+ * of the APICs via firmware parsers or VM guest
+ * mechanisms.
+ */
+ if (apic_id == topo_info.boot_cpu_apic_id)
+ cpu = 0;
+ else
+ cpu = topo_get_cpunr(apic_id);
+ topo_set_cpuids(cpu, apic_id, acpi_id);
+ } else {
+ topo_info.nr_disabled_cpus++;
+ }
}
/**
@@ -255,8 +245,10 @@ void __init topology_register_apic(u32 apic_id, u32 acpi_id, bool present)
*/
void __init topology_register_boot_apic(u32 apic_id)
{
- cpuid_to_apicid[0] = apic_id;
- cpu_update_apic(0, apic_id);
+ WARN_ON_ONCE(topo_info.boot_cpu_apic_id != BAD_APICID);
+
+ topo_info.boot_cpu_apic_id = apic_id;
+ topology_register_apic(apic_id, CPU_ACPIID_INVALID, true);
}
#ifdef CONFIG_ACPI_HOTPLUG_CPU
@@ -274,10 +266,13 @@ int topology_hotplug_apic(u32 apic_id, u32 acpi_id)
cpu = topo_lookup_cpuid(apic_id);
if (cpu < 0) {
- cpu = generic_processor_info(apic_id);
- if (cpu >= 0)
- per_cpu(x86_cpu_to_acpiid, cpu) = acpi_id;
+ if (topo_info.nr_assigned_cpus >= nr_cpu_ids)
+ return -ENOSPC;
+
+ cpu = topo_assign_cpunr(apic_id);
}
+ set_bit(apic_id, phys_cpu_present_map);
+ topo_set_cpuids(cpu, apic_id, acpi_id);
return cpu;
}
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