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Currently arm64 supports per-CPU IRQ stack, but softirqs are still handled in the task context. Since any call to local_bh_enable() at any level in the task's call stack may trigger a softirq processing run, which could potentially cause a task stack overflow if the combined stack footprints exceed the stack's size, let's run these softirqs on the IRQ stack as well. Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20220815124739.15948-1-zhengqi.arch@bytedance.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
136 lines
3.1 KiB
C
136 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Based on arch/arm/kernel/irq.c
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*
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* Copyright (C) 1992 Linus Torvalds
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* Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
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* Support for Dynamic Tick Timer Copyright (C) 2004-2005 Nokia Corporation.
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* Dynamic Tick Timer written by Tony Lindgren <tony@atomide.com> and
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* Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>.
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* Copyright (C) 2012 ARM Ltd.
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*/
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#include <linux/irq.h>
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#include <linux/memory.h>
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#include <linux/smp.h>
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#include <linux/hardirq.h>
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#include <linux/init.h>
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#include <linux/irqchip.h>
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#include <linux/kprobes.h>
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#include <linux/scs.h>
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#include <linux/seq_file.h>
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#include <linux/vmalloc.h>
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#include <asm/daifflags.h>
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#include <asm/exception.h>
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#include <asm/vmap_stack.h>
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#include <asm/softirq_stack.h>
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/* Only access this in an NMI enter/exit */
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DEFINE_PER_CPU(struct nmi_ctx, nmi_contexts);
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DEFINE_PER_CPU(unsigned long *, irq_stack_ptr);
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DECLARE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr);
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#ifdef CONFIG_SHADOW_CALL_STACK
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DEFINE_PER_CPU(unsigned long *, irq_shadow_call_stack_ptr);
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#endif
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static void init_irq_scs(void)
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{
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int cpu;
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if (!IS_ENABLED(CONFIG_SHADOW_CALL_STACK))
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return;
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for_each_possible_cpu(cpu)
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per_cpu(irq_shadow_call_stack_ptr, cpu) =
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scs_alloc(cpu_to_node(cpu));
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}
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#ifdef CONFIG_VMAP_STACK
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static void init_irq_stacks(void)
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{
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int cpu;
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unsigned long *p;
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for_each_possible_cpu(cpu) {
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p = arch_alloc_vmap_stack(IRQ_STACK_SIZE, cpu_to_node(cpu));
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per_cpu(irq_stack_ptr, cpu) = p;
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}
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}
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#else
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/* irq stack only needs to be 16 byte aligned - not IRQ_STACK_SIZE aligned. */
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DEFINE_PER_CPU_ALIGNED(unsigned long [IRQ_STACK_SIZE/sizeof(long)], irq_stack);
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static void init_irq_stacks(void)
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{
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int cpu;
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for_each_possible_cpu(cpu)
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per_cpu(irq_stack_ptr, cpu) = per_cpu(irq_stack, cpu);
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}
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#endif
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#ifndef CONFIG_PREEMPT_RT
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static void ____do_softirq(struct pt_regs *regs)
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{
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__do_softirq();
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}
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void do_softirq_own_stack(void)
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{
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call_on_irq_stack(NULL, ____do_softirq);
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}
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#endif
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static void default_handle_irq(struct pt_regs *regs)
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{
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panic("IRQ taken without a root IRQ handler\n");
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}
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static void default_handle_fiq(struct pt_regs *regs)
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{
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panic("FIQ taken without a root FIQ handler\n");
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}
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void (*handle_arch_irq)(struct pt_regs *) __ro_after_init = default_handle_irq;
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void (*handle_arch_fiq)(struct pt_regs *) __ro_after_init = default_handle_fiq;
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int __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
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{
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if (handle_arch_irq != default_handle_irq)
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return -EBUSY;
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handle_arch_irq = handle_irq;
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pr_info("Root IRQ handler: %ps\n", handle_irq);
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return 0;
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}
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int __init set_handle_fiq(void (*handle_fiq)(struct pt_regs *))
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{
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if (handle_arch_fiq != default_handle_fiq)
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return -EBUSY;
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handle_arch_fiq = handle_fiq;
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pr_info("Root FIQ handler: %ps\n", handle_fiq);
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return 0;
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}
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void __init init_IRQ(void)
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{
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init_irq_stacks();
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init_irq_scs();
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irqchip_init();
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if (system_uses_irq_prio_masking()) {
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/*
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* Now that we have a stack for our IRQ handler, set
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* the PMR/PSR pair to a consistent state.
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*/
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WARN_ON(read_sysreg(daif) & PSR_A_BIT);
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local_daif_restore(DAIF_PROCCTX_NOIRQ);
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}
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}
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