arch/x86/kernel/apic/x2apic_phys.c

Source file repositories/reference/linux-study-clean/arch/x86/kernel/apic/x2apic_phys.c

File Facts

System
Linux kernel
Corpus path
arch/x86/kernel/apic/x2apic_phys.c
Extension
.c
Size
3656 bytes
Lines
160
Domain
Architecture Layer
Bucket
arch/x86
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0

#include <linux/cpumask.h>
#include <linux/acpi.h>

#include "local.h"

int x2apic_phys;

static struct apic apic_x2apic_phys;
u32 x2apic_max_apicid __ro_after_init = UINT_MAX;

void __init x2apic_set_max_apicid(u32 apicid)
{
	x2apic_max_apicid = apicid;
	if (apic->x2apic_set_max_apicid)
		apic->max_apic_id = apicid;
}

static int __init set_x2apic_phys_mode(char *arg)
{
	x2apic_phys = 1;
	return 0;
}
early_param("x2apic_phys", set_x2apic_phys_mode);

static bool x2apic_fadt_phys(void)
{
#ifdef CONFIG_ACPI
	if ((acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID) &&
		(acpi_gbl_FADT.flags & ACPI_FADT_APIC_PHYSICAL)) {
		printk(KERN_DEBUG "System requires x2apic physical mode\n");
		return true;
	}
#endif
	return false;
}

static int x2apic_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
{
	return x2apic_enabled() && (x2apic_phys || x2apic_fadt_phys());
}

static void x2apic_send_IPI(int cpu, int vector)
{
	u32 dest = per_cpu(x86_cpu_to_apicid, cpu);

	/* x2apic MSRs are special and need a special fence: */
	weak_wrmsr_fence();
	__x2apic_send_IPI_dest(dest, vector, APIC_DEST_PHYSICAL);
}

static void
__x2apic_send_IPI_mask(const struct cpumask *mask, int vector, int apic_dest)
{
	unsigned long query_cpu;
	unsigned long this_cpu;
	unsigned long flags;

	/* x2apic MSRs are special and need a special fence: */
	weak_wrmsr_fence();

	local_irq_save(flags);

	this_cpu = smp_processor_id();
	for_each_cpu(query_cpu, mask) {
		if (apic_dest == APIC_DEST_ALLBUT && this_cpu == query_cpu)
			continue;
		__x2apic_send_IPI_dest(per_cpu(x86_cpu_to_apicid, query_cpu),
				       vector, APIC_DEST_PHYSICAL);
	}
	local_irq_restore(flags);
}

static void x2apic_send_IPI_mask(const struct cpumask *mask, int vector)
{
	__x2apic_send_IPI_mask(mask, vector, APIC_DEST_ALLINC);
}

static void
 x2apic_send_IPI_mask_allbutself(const struct cpumask *mask, int vector)
{
	__x2apic_send_IPI_mask(mask, vector, APIC_DEST_ALLBUT);
}

static void __x2apic_send_IPI_shorthand(int vector, u32 which)
{
	unsigned long cfg = __prepare_ICR(which, vector, 0);

	/* x2apic MSRs are special and need a special fence: */

Annotation

Implementation Notes