arch/x86/kernel/vsmp_64.c

Source file repositories/reference/linux-study-clean/arch/x86/kernel/vsmp_64.c

File Facts

System
Linux kernel
Corpus path
arch/x86/kernel/vsmp_64.c
Extension
.c
Size
3058 bytes
Lines
140
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-only
/*
 * vSMPowered(tm) systems specific initialization
 * Copyright (C) 2005 ScaleMP Inc.
 *
 * Ravikiran Thirumalai <kiran@scalemp.com>,
 * Shai Fultheim <shai@scalemp.com>
 * Paravirt ops integration: Glauber de Oliveira Costa <gcosta@redhat.com>,
 *			     Ravikiran Thirumalai <kiran@scalemp.com>
 */

#include <linux/init.h>
#include <linux/pci_ids.h>
#include <linux/pci_regs.h>
#include <linux/smp.h>
#include <linux/irq.h>

#include <asm/apic.h>
#include <asm/pci-direct.h>
#include <asm/io.h>
#include <asm/setup.h>

#define TOPOLOGY_REGISTER_OFFSET 0x10

#ifdef CONFIG_PCI
static void __init set_vsmp_ctl(void)
{
	void __iomem *address;
	unsigned int cap, ctl, cfg;

	/* set vSMP magic bits to indicate vSMP capable kernel */
	cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
	address = early_ioremap(cfg, 8);
	cap = readl(address);
	ctl = readl(address + 4);
	printk(KERN_INFO "vSMP CTL: capabilities:0x%08x  control:0x%08x\n",
	       cap, ctl);

	/* If possible, let the vSMP foundation route the interrupt optimally */
#ifdef CONFIG_SMP
	if (cap & ctl & BIT(8)) {
		ctl &= ~BIT(8);

#ifdef CONFIG_PROC_FS
		/* Don't let users change irq affinity via procfs */
		no_irq_affinity = 1;
#endif
	}
#endif

	writel(ctl, address + 4);
	ctl = readl(address + 4);
	pr_info("vSMP CTL: control set to:0x%08x\n", ctl);

	early_iounmap(address, 8);
}
static int is_vsmp = -1;

static void __init detect_vsmp_box(void)
{
	is_vsmp = 0;

	if (!early_pci_allowed())
		return;

	/* Check if we are running on a ScaleMP vSMPowered box */
	if (read_pci_config(0, 0x1f, 0, PCI_VENDOR_ID) ==
	     (PCI_VENDOR_ID_SCALEMP | (PCI_DEVICE_ID_SCALEMP_VSMP_CTL << 16)))
		is_vsmp = 1;
}

static int is_vsmp_box(void)
{
	if (is_vsmp != -1)
		return is_vsmp;
	else {
		WARN_ON_ONCE(1);
		return 0;
	}
}

#else
static void __init detect_vsmp_box(void)
{
}
static int is_vsmp_box(void)
{
	return 0;
}
static void __init set_vsmp_ctl(void)

Annotation

Implementation Notes