1 files changed, 76 insertions, 0 deletions
diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
new file mode 100644
index 0000000000..fe0c859873
--- /dev/null
+++ b/arch/x86/kernel/irq_64.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *	Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
+ *
+ * This file contains the lowest level x86_64-specific interrupt
+ * entry and irq statistics code. All the remaining irq logic is
+ * done by the generic kernel/irq/ code and in the
+ * x86_64-specific irq controller code. (e.g. i8259.c and
+ * io_apic.c.)
+ */
+
+#include <linux/kernel_stat.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/seq_file.h>
+#include <linux/delay.h>
+#include <linux/ftrace.h>
+#include <linux/uaccess.h>
+#include <linux/smp.h>
+#include <linux/sched/task_stack.h>
+
+#include <asm/cpu_entry_area.h>
+#include <asm/softirq_stack.h>
+#include <asm/irq_stack.h>
+#include <asm/io_apic.h>
+#include <asm/apic.h>
+
+DEFINE_PER_CPU_PAGE_ALIGNED(struct irq_stack, irq_stack_backing_store) __visible;
+DECLARE_INIT_PER_CPU(irq_stack_backing_store);
+
+#ifdef CONFIG_VMAP_STACK
+/*
+ * VMAP the backing store with guard pages
+ */
+static int map_irq_stack(unsigned int cpu)
+{
+	char *stack = (char *)per_cpu_ptr(&irq_stack_backing_store, cpu);
+	struct page *pages[IRQ_STACK_SIZE / PAGE_SIZE];
+	void *va;
+	int i;
+
+	for (i = 0; i < IRQ_STACK_SIZE / PAGE_SIZE; i++) {
+		phys_addr_t pa = per_cpu_ptr_to_phys(stack + (i << PAGE_SHIFT));
+
+		pages[i] = pfn_to_page(pa >> PAGE_SHIFT);
+	}
+
+	va = vmap(pages, IRQ_STACK_SIZE / PAGE_SIZE, VM_MAP, PAGE_KERNEL);
+	if (!va)
+		return -ENOMEM;
+
+	/* Store actual TOS to avoid adjustment in the hotpath */
+	per_cpu(pcpu_hot.hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE - 8;
+	return 0;
+}
+#else
+/*
+ * If VMAP stacks are disabled due to KASAN, just use the per cpu
+ * backing store without guard pages.
+ */
+static int map_irq_stack(unsigned int cpu)
+{
+	void *va = per_cpu_ptr(&irq_stack_backing_store, cpu);
+
+	/* Store actual TOS to avoid adjustment in the hotpath */
+	per_cpu(pcpu_hot.hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE - 8;
+	return 0;
+}
+#endif
+
+int irq_init_percpu_irqstack(unsigned int cpu)
+{
+	if (per_cpu(pcpu_hot.hardirq_stack_ptr, cpu))
+		return 0;
+	return map_irq_stack(cpu);
+}