Commit 72530464 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

x86/cpu/topology: Use a data structure for topology info 



Put the processor accounting into a data structure, which will gain more
topology related information in the next steps, and sanitize the accounting.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarMichael Kelley <mhklinux@outlook.com>
Tested-by: default avatarSohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20240213210252.111451909@linutronix.de
parent 4c4c6f38

arch/x86/kernel/cpu/topology.c

+29 −30
Original line number Diff line number Diff line
@@ -22,6 +22,18 @@ DECLARE_BITMAP(phys_cpu_present_map, MAX_LOCAL_APIC) __read_mostly; 
/* Used for CPU number allocation and parallel CPU bringup */

u32 cpuid_to_apicid[] __read_mostly = { [0 ... NR_CPUS - 1] = BAD_APICID, };



/*

 * Keep track of assigned, disabled and rejected CPUs. Present assigned

 * with 1 as CPU #0 is reserved for the boot CPU.

 */

static struct {

	unsigned int		nr_assigned_cpus;

	unsigned int		nr_disabled_cpus;

	unsigned int		nr_rejected_cpus;

} topo_info __read_mostly = {

	.nr_assigned_cpus	= 1,

};



/*

 * Processor to be disabled specified by kernel parameter

 * disable_cpu_apicid=<int>, mostly used for the kdump 2nd kernel to
@@ -29,19 +41,6 @@ u32 cpuid_to_apicid[] __read_mostly = { [0 ... NR_CPUS - 1] = BAD_APICID, }; 
 */

static u32 disabled_cpu_apicid __ro_after_init = BAD_APICID;



static unsigned int num_processors;

static unsigned int disabled_cpus;



/*

 * The number of allocated logical CPU IDs. Since logical CPU IDs are allocated

 * contiguously, it equals to current allocated max logical CPU ID plus 1.

 * All allocated CPU IDs should be in the [0, nr_logical_cpuids) range,

 * so the maximum of nr_logical_cpuids is nr_cpu_ids.

 *

 * NOTE: Reserve 0 for BSP.

 */

static int nr_logical_cpuids = 1;



bool arch_match_cpu_phys_id(int cpu, u64 phys_id)

{

	return phys_id == (u64)cpuid_to_apicid[cpu];
@@ -75,7 +74,7 @@ static int __init smp_init_primary_thread_mask(void) 
		return 0;

	}



	for (cpu = 0; cpu < nr_logical_cpuids; cpu++)

	for (cpu = 0; cpu < topo_info.nr_assigned_cpus; cpu++)

		cpu_mark_primary_thread(cpu, cpuid_to_apicid[cpu]);

	return 0;

}
@@ -89,7 +88,7 @@ static int topo_lookup_cpuid(u32 apic_id) 
	int i;



	/* CPU# to APICID mapping is persistent once it is established */

	for (i = 0; i < nr_logical_cpuids; i++) {

	for (i = 0; i < topo_info.nr_assigned_cpus; i++) {

		if (cpuid_to_apicid[i] == apic_id)

			return i;

	}
@@ -107,22 +106,21 @@ static int allocate_logical_cpuid(u32 apic_id) 
	if (cpu >= 0)

		return cpu;



	cpuid_to_apicid[nr_logical_cpuids] = apic_id;

	return nr_logical_cpuids++;

	return topo_info.nr_assigned_cpus++;

}



static void cpu_update_apic(int cpu, u32 apicid)

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) = apicid;

	early_per_cpu(x86_cpu_to_apicid, cpu) = apic_id;

#endif

	cpuid_to_apicid[cpu] = apic_id;

	set_cpu_possible(cpu, true);

	set_bit(apicid, phys_cpu_present_map);

	set_bit(apic_id, phys_cpu_present_map);

	set_cpu_present(cpu, true);

	num_processors++;



	if (system_state != SYSTEM_BOOTING)

		cpu_mark_primary_thread(cpu, apicid);

		cpu_mark_primary_thread(cpu, apic_id);

}



static int generic_processor_info(int apicid)
@@ -137,18 +135,18 @@ static int generic_processor_info(int apicid) 
		return 0;



	if (disabled_cpu_apicid == apicid) {

		int thiscpu = num_processors + disabled_cpus;

		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);



		disabled_cpus++;

		topo_info.nr_rejected_cpus++;

		return -ENODEV;

	}



	if (num_processors >= nr_cpu_ids) {

	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);

		disabled_cpus++;

		topo_info.nr_rejected_cpus++;

		return -ENOSPC;

	}
@@ -178,14 +176,16 @@ static int __initdata setup_possible_cpus = -1; 
 */

__init void prefill_possible_map(void)

{

	unsigned int num_processors = topo_info.nr_assigned_cpus;

	unsigned int disabled_cpus = topo_info.nr_disabled_cpus;

	int i, possible;



	i = setup_max_cpus ?: 1;

	if (setup_possible_cpus == -1) {

		possible = num_processors;

		possible = topo_info.nr_assigned_cpus;

#ifdef CONFIG_HOTPLUG_CPU

		if (setup_max_cpus)

			possible += disabled_cpus;

			possible += num_processors;

#else

		if (possible > i)

			possible = i;
@@ -238,7 +238,7 @@ void __init topology_register_apic(u32 apic_id, u32 acpi_id, bool present) 
	}



	if (!present) {

		disabled_cpus++;

		topo_info.nr_disabled_cpus++;

		return;

	}
@@ -295,7 +295,6 @@ void topology_hotunplug_apic(unsigned int cpu) 
	per_cpu(x86_cpu_to_apicid, cpu) = BAD_APICID;

	clear_bit(apic_id, phys_cpu_present_map);

	set_cpu_present(cpu, false);

	num_processors--;

}

#endif