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x86/cpu/topology: Sanitize the APIC admission logic

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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@linutronix.de>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20240213210252.230433953@linutronix.de
This commit is contained in:
Thomas Gleixner 2024-02-13 22:05:52 +01:00
parent 6055f6cf0d
commit 0e53e7b656
1 changed files with 78 additions and 83 deletions
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161
arch/x86/kernel/cpu/topology.c
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@ -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) {
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 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++;
return;
}
cpu = generic_processor_info(apic_id);
if (cpu >= 0)
early_per_cpu(x86_cpu_to_acpiid, cpu) = acpi_id;
}
/**
@ -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;
}