disable FB

hc

2024-01-04 1543e317f1da31b75942316931e8f491a8920811

 kernel/arch/x86/kernel/irq_64.c
..
..
@@ -18,72 +18,61 @@
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 #include <linux/uaccess.h>
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 #include <linux/smp.h>
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 #include <linux/sched/task_stack.h>
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+
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+#include <asm/cpu_entry_area.h>
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+#include <asm/irq_stack.h>
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 #include <asm/io_apic.h>
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 #include <asm/apic.h>
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26
 
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-int sysctl_panic_on_stackoverflow;
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+DEFINE_PER_CPU_PAGE_ALIGNED(struct irq_stack, irq_stack_backing_store) __visible;
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+DECLARE_INIT_PER_CPU(irq_stack_backing_store);
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29
 
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+#ifdef CONFIG_VMAP_STACK
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 /*
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- * Probabilistic stack overflow check:
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- *
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- * Regular device interrupts can enter on the following stacks:
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- *
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- * - User stack
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- *
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- * - Kernel task stack
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- *
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- * - Interrupt stack if a device driver reenables interrupts
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- *   which should only happen in really old drivers.
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- *
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- * - Debug IST stack
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- *
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- * All other contexts are invalid.
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+ * VMAP the backing store with guard pages
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  */
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-static inline void stack_overflow_check(struct pt_regs *regs)
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+static int map_irq_stack(unsigned int cpu)
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 {
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-#ifdef CONFIG_DEBUG_STACKOVERFLOW
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-#define STACK_TOP_MARGIN	128
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-	struct orig_ist *oist;
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-	u64 irq_stack_top, irq_stack_bottom;
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-	u64 estack_top, estack_bottom;
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-	u64 curbase = (u64)task_stack_page(current);
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+	char *stack = (char *)per_cpu_ptr(&irq_stack_backing_store, cpu);
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+	struct page *pages[IRQ_STACK_SIZE / PAGE_SIZE];
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+	void *va;
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+	int i;
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40
 
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-	if (user_mode(regs))
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-		return;
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+	for (i = 0; i < IRQ_STACK_SIZE / PAGE_SIZE; i++) {
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+		phys_addr_t pa = per_cpu_ptr_to_phys(stack + (i << PAGE_SHIFT));
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43
 
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-	if (regs->sp >= curbase + sizeof(struct pt_regs) + STACK_TOP_MARGIN &&
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-	    regs->sp <= curbase + THREAD_SIZE)
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-		return;
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+		pages[i] = pfn_to_page(pa >> PAGE_SHIFT);
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+	}
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-	irq_stack_top = (u64)this_cpu_ptr(irq_stack_union.irq_stack) +
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-			STACK_TOP_MARGIN;
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-	irq_stack_bottom = (u64)__this_cpu_read(irq_stack_ptr);
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-	if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
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-		return;
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+	va = vmap(pages, IRQ_STACK_SIZE / PAGE_SIZE, VM_MAP, PAGE_KERNEL);
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+	if (!va)
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+		return -ENOMEM;
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-	oist = this_cpu_ptr(&orig_ist);
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-	estack_bottom = (u64)oist->ist[DEBUG_STACK];
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-	estack_top = estack_bottom - DEBUG_STKSZ + STACK_TOP_MARGIN;
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-	if (regs->sp >= estack_top && regs->sp <= estack_bottom)
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-		return;
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+	per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE;
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+	return 0;
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+}
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+#else
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+/*
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+ * If VMAP stacks are disabled due to KASAN, just use the per cpu
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+ * backing store without guard pages.
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+ */
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+static int map_irq_stack(unsigned int cpu)
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+{
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+	void *va = per_cpu_ptr(&irq_stack_backing_store, cpu);
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62
 
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-	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",
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-		current->comm, curbase, regs->sp,
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-		irq_stack_top, irq_stack_bottom,
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-		estack_top, estack_bottom, (void *)regs->ip);
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-
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-	if (sysctl_panic_on_stackoverflow)
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-		panic("low stack detected by irq handler - check messages\n");
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+	per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE;
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+	return 0;
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+}
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 #endif
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+
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+int irq_init_percpu_irqstack(unsigned int cpu)
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+{
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+	if (per_cpu(hardirq_stack_ptr, cpu))
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+		return 0;
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+	return map_irq_stack(cpu);
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 }
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74
 
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-bool handle_irq(struct irq_desc *desc, struct pt_regs *regs)
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+void do_softirq_own_stack(void)
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 {
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-	stack_overflow_check(regs);
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-
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-	if (IS_ERR_OR_NULL(desc))
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-		return false;
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-
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-	generic_handle_irq_desc(desc);
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-	return true;
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+	run_on_irqstack_cond(__do_softirq, NULL);
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 }