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https://github.com/torvalds/linux
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117ed45485
All stack types on x86 64-bit have guard pages now. So there is no point in executing probabilistic overflow checks as the guard pages are a accurate and reliable overflow prevention. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Nicolai Stange <nstange@suse.de> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20190414160146.466354762@linutronix.de
82 lines
1.9 KiB
C
82 lines
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
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*
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* This file contains the lowest level x86_64-specific interrupt
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* entry and irq statistics code. All the remaining irq logic is
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* done by the generic kernel/irq/ code and in the
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* x86_64-specific irq controller code. (e.g. i8259.c and
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* io_apic.c.)
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*/
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#include <linux/kernel_stat.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/seq_file.h>
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#include <linux/delay.h>
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#include <linux/ftrace.h>
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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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#include <asm/cpu_entry_area.h>
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#include <asm/io_apic.h>
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#include <asm/apic.h>
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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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bool handle_irq(struct irq_desc *desc, struct pt_regs *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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generic_handle_irq_desc(desc);
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return true;
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}
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#ifdef CONFIG_VMAP_STACK
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/*
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* VMAP the backing store with 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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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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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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pages[i] = pfn_to_page(pa >> PAGE_SHIFT);
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}
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va = vmap(pages, IRQ_STACK_SIZE / PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
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if (!va)
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return -ENOMEM;
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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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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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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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