1 files changed, 140 insertions, 0 deletions
diff --git a/arch/x86/kernel/apic/probe_32.c b/arch/x86/kernel/apic/probe_32.c
new file mode 100644
index 000000000..9a06df6cd
--- /dev/null
+++ b/arch/x86/kernel/apic/probe_32.c
@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Default generic APIC driver. This handles up to 8 CPUs.
+ *
+ * Copyright 2003 Andi Kleen, SuSE Labs.
+ *
+ * Generic x86 APIC driver probe layer.
+ */
+#include <linux/export.h>
+#include <linux/errno.h>
+#include <linux/smp.h>
+
+#include <xen/xen.h>
+
+#include <asm/io_apic.h>
+#include <asm/apic.h>
+#include <asm/acpi.h>
+
+#include "local.h"
+
+static int default_phys_pkg_id(int cpuid_apic, int index_msb)
+{
+	return cpuid_apic >> index_msb;
+}
+
+/* should be called last. */
+static int probe_default(void)
+{
+	return 1;
+}
+
+static struct apic apic_default __ro_after_init = {
+
+	.name				= "default",
+	.probe				= probe_default,
+	.apic_id_registered		= default_apic_id_registered,
+
+	.delivery_mode			= APIC_DELIVERY_MODE_FIXED,
+	.dest_mode_logical		= true,
+
+	.disable_esr			= 0,
+
+	.check_apicid_used		= default_check_apicid_used,
+	.init_apic_ldr			= default_init_apic_ldr,
+	.ioapic_phys_id_map		= default_ioapic_phys_id_map,
+	.cpu_present_to_apicid		= default_cpu_present_to_apicid,
+	.phys_pkg_id			= default_phys_pkg_id,
+
+	.max_apic_id			= 0xFE,
+	.get_apic_id			= default_get_apic_id,
+
+	.calc_dest_apicid		= apic_flat_calc_apicid,
+
+	.send_IPI			= default_send_IPI_single,
+	.send_IPI_mask			= default_send_IPI_mask_logical,
+	.send_IPI_mask_allbutself	= default_send_IPI_mask_allbutself_logical,
+	.send_IPI_allbutself		= default_send_IPI_allbutself,
+	.send_IPI_all			= default_send_IPI_all,
+	.send_IPI_self			= default_send_IPI_self,
+
+	.read				= native_apic_mem_read,
+	.write				= native_apic_mem_write,
+	.eoi				= native_apic_mem_eoi,
+	.icr_read			= native_apic_icr_read,
+	.icr_write			= native_apic_icr_write,
+	.wait_icr_idle			= apic_mem_wait_icr_idle,
+	.safe_wait_icr_idle		= apic_mem_wait_icr_idle_timeout,
+};
+
+apic_driver(apic_default);
+
+struct apic *apic __ro_after_init = &apic_default;
+EXPORT_SYMBOL_GPL(apic);
+
+static int cmdline_apic __initdata;
+static int __init parse_apic(char *arg)
+{
+	struct apic **drv;
+
+	if (!arg)
+		return -EINVAL;
+
+	for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
+		if (!strcmp((*drv)->name, arg)) {
+			apic_install_driver(*drv);
+			cmdline_apic = 1;
+			return 0;
+		}
+	}
+
+	/* Parsed again by __setup for debug/verbose */
+	return 0;
+}
+early_param("apic", parse_apic);
+
+void __init x86_32_probe_bigsmp_early(void)
+{
+	if (nr_cpu_ids <= 8 || xen_pv_domain())
+		return;
+
+	if (IS_ENABLED(CONFIG_X86_BIGSMP)) {
+		switch (boot_cpu_data.x86_vendor) {
+		case X86_VENDOR_INTEL:
+			if (!APIC_XAPIC(boot_cpu_apic_version))
+				break;
+			/* P4 and above */
+			fallthrough;
+		case X86_VENDOR_HYGON:
+		case X86_VENDOR_AMD:
+			if (apic_bigsmp_possible(cmdline_apic))
+				return;
+			break;
+		}
+	}
+	pr_info("Limiting to 8 possible CPUs\n");
+	set_nr_cpu_ids(8);
+}
+
+void __init x86_32_install_bigsmp(void)
+{
+	if (nr_cpu_ids > 8 && !xen_pv_domain())
+		apic_bigsmp_force();
+}
+
+void __init x86_32_probe_apic(void)
+{
+	if (!cmdline_apic) {
+		struct apic **drv;
+
+		for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
+			if ((*drv)->probe()) {
+				apic_install_driver(*drv);
+				break;
+			}
+		}
+		/* Not visible without early console */
+		if (drv == __apicdrivers_end)
+			panic("Didn't find an APIC driver");
+	}
+}