Commit c0a66c28 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

x86/cpu/topology: Move registration out of APIC code 



The APIC/CPU registration sits in the middle of the APIC code. In fact this
is a topology evaluation function and has nothing to do with the inner
workings of the local APIC.

Move it out into a file which reflects what this is about.

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/20240213210251.543948812@linutronix.de
parent 1a5d0f62

arch/x86/include/asm/apic.h

+2 −0
Original line number Diff line number Diff line
@@ -171,6 +171,8 @@ extern bool apic_needs_pit(void); 


extern void apic_send_IPI_allbutself(unsigned int vector);



extern void topology_register_boot_apic(u32 apic_id);



#else /* !CONFIG_X86_LOCAL_APIC */

static inline void lapic_shutdown(void) { }

#define local_apic_timer_c2_ok		1

arch/x86/kernel/apic/apic.c

+2 −183
Original line number Diff line number Diff line
@@ -68,26 +68,12 @@ 


#include "local.h"



unsigned int num_processors;



unsigned disabled_cpus;



/* Processor that is doing the boot up */

u32 boot_cpu_physical_apicid __ro_after_init = BAD_APICID;

EXPORT_SYMBOL_GPL(boot_cpu_physical_apicid);



u8 boot_cpu_apic_version __ro_after_init;



/* Bitmap of physically present CPUs. */

DECLARE_BITMAP(phys_cpu_present_map, MAX_LOCAL_APIC);



/*

 * Processor to be disabled specified by kernel parameter

 * disable_cpu_apicid=<int>, mostly used for the kdump 2nd kernel to

 * avoid undefined behaviour caused by sending INIT from AP to BSP.

 */

static u32 disabled_cpu_apicid __ro_after_init = BAD_APICID;



/*

 * This variable controls which CPUs receive external NMIs.  By default,

 * external NMIs are delivered only to the BSP.
@@ -107,14 +93,6 @@ static inline bool apic_accessible(void) 
	return x2apic_mode || apic_mmio_base;

}



/*

 * Map cpu index to physical APIC ID

 */

DEFINE_EARLY_PER_CPU_READ_MOSTLY(u32, x86_cpu_to_apicid, BAD_APICID);

DEFINE_EARLY_PER_CPU_READ_MOSTLY(u32, x86_cpu_to_acpiid, CPU_ACPIID_INVALID);

EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_apicid);

EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_acpiid);



#ifdef CONFIG_X86_32

/* Local APIC was disabled by the BIOS and enabled by the kernel */

static int enabled_via_apicbase __ro_after_init;
@@ -1676,8 +1654,6 @@ void apic_ap_setup(void) 
	end_local_APIC_setup();

}



static __init void cpu_set_boot_apic(void);



static __init void apic_read_boot_cpu_id(bool x2apic)

{

	/*
@@ -1692,7 +1668,8 @@ static __init void apic_read_boot_cpu_id(bool x2apic) 
		boot_cpu_physical_apicid = read_apic_id();

		boot_cpu_apic_version = GET_APIC_VERSION(apic_read(APIC_LVR));

	}

	cpu_set_boot_apic();

	topology_register_boot_apic(boot_cpu_physical_apicid);

	x86_32_probe_bigsmp_early();

}



#ifdef CONFIG_X86_X2APIC
@@ -2291,155 +2268,6 @@ void disconnect_bsp_APIC(int virt_wire_setup) 
	apic_write(APIC_LVT1, value);

}



/*

 * 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;



/*

 * Used to store mapping between logical CPU IDs and APIC IDs.

 */

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



bool arch_match_cpu_phys_id(int cpu, u64 phys_id)

{

	return phys_id == (u64)cpuid_to_apicid[cpu];

}



#ifdef CONFIG_SMP

static void cpu_mark_primary_thread(unsigned int cpu, unsigned int apicid)

{

	/* Isolate the SMT bit(s) in the APICID and check for 0 */

	u32 mask = (1U << (fls(smp_num_siblings) - 1)) - 1;



	if (smp_num_siblings == 1 || !(apicid & mask))

		cpumask_set_cpu(cpu, &__cpu_primary_thread_mask);

}



/*

 * Due to the utter mess of CPUID evaluation smp_num_siblings is not valid

 * during early boot. Initialize the primary thread mask before SMP

 * bringup.

 */

static int __init smp_init_primary_thread_mask(void)

{

	unsigned int cpu;



	/*

	 * XEN/PV provides either none or useless topology information.

	 * Pretend that all vCPUs are primary threads.

	 */

	if (xen_pv_domain()) {

		cpumask_copy(&__cpu_primary_thread_mask, cpu_possible_mask);

		return 0;

	}



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

		cpu_mark_primary_thread(cpu, cpuid_to_apicid[cpu]);

	return 0;

}

early_initcall(smp_init_primary_thread_mask);

#else

static inline void cpu_mark_primary_thread(unsigned int cpu, unsigned int apicid) { }

#endif



/*

 * Should use this API to allocate logical CPU IDs to keep nr_logical_cpuids

 * and cpuid_to_apicid[] synchronized.

 */

static int allocate_logical_cpuid(int apicid)

{

	int i;



	/*

	 * cpuid <-> apicid mapping is persistent, so when a cpu is up,

	 * check if the kernel has allocated a cpuid for it.

	 */

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

		if (cpuid_to_apicid[i] == apicid)

			return i;

	}



	/* Allocate a new cpuid. */

	if (nr_logical_cpuids >= nr_cpu_ids) {

		WARN_ONCE(1, "APIC: NR_CPUS/possible_cpus limit of %u reached. "

			     "Processor %d/0x%x and the rest are ignored.\n",

			     nr_cpu_ids, nr_logical_cpuids, apicid);

		return -EINVAL;

	}



	cpuid_to_apicid[nr_logical_cpuids] = apicid;

	return nr_logical_cpuids++;

}



static void cpu_update_apic(int cpu, u32 apicid)

{

#if defined(CONFIG_SMP) || defined(CONFIG_X86_64)

	early_per_cpu(x86_cpu_to_apicid, cpu) = apicid;

#endif

	set_cpu_possible(cpu, true);

	set_bit(apicid, phys_cpu_present_map);

	set_cpu_present(cpu, true);

	num_processors++;



	if (system_state != SYSTEM_BOOTING)

		cpu_mark_primary_thread(cpu, apicid);

}



static __init void cpu_set_boot_apic(void)

{

	cpuid_to_apicid[0] = boot_cpu_physical_apicid;

	cpu_update_apic(0, boot_cpu_physical_apicid);

	x86_32_probe_bigsmp_early();

}



int generic_processor_info(int apicid)

{

	int cpu, max = nr_cpu_ids;



	/* 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 = num_processors + disabled_cpus;



		pr_warn("APIC: Disabling requested cpu. Processor %d/0x%x ignored.\n",

			thiscpu, apicid);



		disabled_cpus++;

		return -ENODEV;

	}



	if (num_processors >= nr_cpu_ids) {

		int thiscpu = max + disabled_cpus;



		pr_warn("APIC: NR_CPUS/possible_cpus limit of %i reached. "

			"Processor %d/0x%x ignored.\n", max, thiscpu, apicid);



		disabled_cpus++;

		return -EINVAL;

	}



	cpu = allocate_logical_cpuid(apicid);

	if (cpu < 0) {

		disabled_cpus++;

		return -EINVAL;

	}



	cpu_update_apic(cpu, apicid);

	return cpu;

}





void __irq_msi_compose_msg(struct irq_cfg *cfg, struct msi_msg *msg,

			   bool dmar)

{
@@ -2828,15 +2656,6 @@ static int __init lapic_insert_resource(void) 
 */

late_initcall(lapic_insert_resource);



static int __init apic_set_disabled_cpu_apicid(char *arg)

{

	if (!arg || !get_option(&arg, &disabled_cpu_apicid))

		return -EINVAL;



	return 0;

}

early_param("disable_cpu_apicid", apic_set_disabled_cpu_apicid);



static int __init apic_set_extnmi(char *arg)

{

	if (!arg)

arch/x86/kernel/cpu/Makefile

+7 −5
Original line number Diff line number Diff line
@@ -26,9 +26,11 @@ obj-y += bugs.o 
obj-y			+= aperfmperf.o

obj-y			+= cpuid-deps.o

obj-y			+= umwait.o

obj-y 			+= capflags.o powerflags.o



obj-$(CONFIG_X86_LOCAL_APIC)		+= topology.o



obj-$(CONFIG_PROC_FS)			+= proc.o

obj-y += capflags.o powerflags.o



obj-$(CONFIG_IA32_FEAT_CTL)		+= feat_ctl.o

ifdef CONFIG_CPU_SUP_INTEL

arch/x86/kernel/cpu/topology.c

0 → 100644
+184 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only



#include <linux/cpu.h>



#include <xen/xen.h>



#include <asm/apic.h>

#include <asm/mpspec.h>

#include <asm/smp.h>



/*

 * Map cpu index to physical APIC ID

 */

DEFINE_EARLY_PER_CPU_READ_MOSTLY(u32, x86_cpu_to_apicid, BAD_APICID);

DEFINE_EARLY_PER_CPU_READ_MOSTLY(u32, x86_cpu_to_acpiid, CPU_ACPIID_INVALID);

EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_apicid);

EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_acpiid);



/* Bitmap of physically present CPUs. */

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, };



/*

 * Processor to be disabled specified by kernel parameter

 * disable_cpu_apicid=<int>, mostly used for the kdump 2nd kernel to

 * avoid undefined behaviour caused by sending INIT from AP to BSP.

 */

static u32 disabled_cpu_apicid __ro_after_init = BAD_APICID;



unsigned int num_processors;

unsigned 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];

}



#ifdef CONFIG_SMP

static void cpu_mark_primary_thread(unsigned int cpu, unsigned int apicid)

{

	/* Isolate the SMT bit(s) in the APICID and check for 0 */

	u32 mask = (1U << (fls(smp_num_siblings) - 1)) - 1;



	if (smp_num_siblings == 1 || !(apicid & mask))

		cpumask_set_cpu(cpu, &__cpu_primary_thread_mask);

}



/*

 * Due to the utter mess of CPUID evaluation smp_num_siblings is not valid

 * during early boot. Initialize the primary thread mask before SMP

 * bringup.

 */

static int __init smp_init_primary_thread_mask(void)

{

	unsigned int cpu;



	/*

	 * XEN/PV provides either none or useless topology information.

	 * Pretend that all vCPUs are primary threads.

	 */

	if (xen_pv_domain()) {

		cpumask_copy(&__cpu_primary_thread_mask, cpu_possible_mask);

		return 0;

	}



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

		cpu_mark_primary_thread(cpu, cpuid_to_apicid[cpu]);

	return 0;

}

early_initcall(smp_init_primary_thread_mask);

#else

static inline void cpu_mark_primary_thread(unsigned int cpu, unsigned int apicid) { }

#endif



/*

 * Should use this API to allocate logical CPU IDs to keep nr_logical_cpuids

 * and cpuid_to_apicid[] synchronized.

 */

static int allocate_logical_cpuid(int apicid)

{

	int i;



	/*

	 * cpuid <-> apicid mapping is persistent, so when a cpu is up,

	 * check if the kernel has allocated a cpuid for it.

	 */

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

		if (cpuid_to_apicid[i] == apicid)

			return i;

	}



	/* Allocate a new cpuid. */

	if (nr_logical_cpuids >= nr_cpu_ids) {

		WARN_ONCE(1, "APIC: NR_CPUS/possible_cpus limit of %u reached. "

			     "Processor %d/0x%x and the rest are ignored.\n",

			     nr_cpu_ids, nr_logical_cpuids, apicid);

		return -EINVAL;

	}



	cpuid_to_apicid[nr_logical_cpuids] = apicid;

	return nr_logical_cpuids++;

}



static void cpu_update_apic(int cpu, u32 apicid)

{

#if defined(CONFIG_SMP) || defined(CONFIG_X86_64)

	early_per_cpu(x86_cpu_to_apicid, cpu) = apicid;

#endif

	set_cpu_possible(cpu, true);

	set_bit(apicid, phys_cpu_present_map);

	set_cpu_present(cpu, true);

	num_processors++;



	if (system_state != SYSTEM_BOOTING)

		cpu_mark_primary_thread(cpu, apicid);

}



void __init topology_register_boot_apic(u32 apic_id)

{

	cpuid_to_apicid[0] = apic_id;

	cpu_update_apic(0, apic_id);

}



int generic_processor_info(int apicid)

{

	int cpu, max = nr_cpu_ids;



	/* 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 = num_processors + disabled_cpus;



		pr_warn("APIC: Disabling requested cpu. Processor %d/0x%x ignored.\n",

			thiscpu, apicid);



		disabled_cpus++;

		return -ENODEV;

	}



	if (num_processors >= nr_cpu_ids) {

		int thiscpu = max + disabled_cpus;



		pr_warn("APIC: NR_CPUS/possible_cpus limit of %i reached. "

			"Processor %d/0x%x ignored.\n", max, thiscpu, apicid);



		disabled_cpus++;

		return -EINVAL;

	}



	cpu = allocate_logical_cpuid(apicid);

	if (cpu < 0) {

		disabled_cpus++;

		return -EINVAL;

	}



	cpu_update_apic(cpu, apicid);

	return cpu;

}



static int __init apic_set_disabled_cpu_apicid(char *arg)

{

	if (!arg || !get_option(&arg, &disabled_cpu_apicid))

		return -EINVAL;



	return 0;

}

early_param("disable_cpu_apicid", apic_set_disabled_cpu_apicid);