From 76cb841cb886eef6b3bee341a2266c76578724ad Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Mon, 6 May 2024 03:02:30 +0200
Subject: Adding upstream version 4.19.249.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 arch/x86/kernel/irq_64.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)
 create mode 100644 arch/x86/kernel/irq_64.c

(limited to 'arch/x86/kernel/irq_64.c')

diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
new file mode 100644
index 000000000..b50ac9c73
--- /dev/null
+++ b/arch/x86/kernel/irq_64.c
@@ -0,0 +1,89 @@
+// 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/io_apic.h>
+#include <asm/apic.h>
+
+int sysctl_panic_on_stackoverflow;
+
+/*
+ * Probabilistic stack overflow check:
+ *
+ * Regular device interrupts can enter on the following stacks:
+ *
+ * - User stack
+ *
+ * - Kernel task stack
+ *
+ * - Interrupt stack if a device driver reenables interrupts
+ *   which should only happen in really old drivers.
+ *
+ * - Debug IST stack
+ *
+ * All other contexts are invalid.
+ */
+static inline void stack_overflow_check(struct pt_regs *regs)
+{
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
+#define STACK_TOP_MARGIN	128
+	struct orig_ist *oist;
+	u64 irq_stack_top, irq_stack_bottom;
+	u64 estack_top, estack_bottom;
+	u64 curbase = (u64)task_stack_page(current);
+
+	if (user_mode(regs))
+		return;
+
+	if (regs->sp >= curbase + sizeof(struct pt_regs) + STACK_TOP_MARGIN &&
+	    regs->sp <= curbase + THREAD_SIZE)
+		return;
+
+	irq_stack_top = (u64)this_cpu_ptr(irq_stack_union.irq_stack) +
+			STACK_TOP_MARGIN;
+	irq_stack_bottom = (u64)__this_cpu_read(irq_stack_ptr);
+	if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
+		return;
+
+	oist = this_cpu_ptr(&orig_ist);
+	estack_bottom = (u64)oist->ist[DEBUG_STACK];
+	estack_top = estack_bottom - DEBUG_STKSZ + STACK_TOP_MARGIN;
+	if (regs->sp >= estack_top && regs->sp <= estack_bottom)
+		return;
+
+	WARN_ONCE(1, "do_IRQ(): %s has overflown the kernel stack (cur:%Lx,sp:%lx,irq stk top-bottom:%Lx-%Lx,exception stk top-bottom:%Lx-%Lx,ip:%pF)\n",
+		current->comm, curbase, regs->sp,
+		irq_stack_top, irq_stack_bottom,
+		estack_top, estack_bottom, (void *)regs->ip);
+
+	if (sysctl_panic_on_stackoverflow)
+		panic("low stack detected by irq handler - check messages\n");
+#endif
+}
+
+bool handle_irq(struct irq_desc *desc, struct pt_regs *regs)
+{
+	stack_overflow_check(regs);
+
+	if (IS_ERR_OR_NULL(desc))
+		return false;
+
+	generic_handle_irq_desc(desc);
+	return true;
+}
-- 
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