目錄

• • • • 1、linux kernel arm32的中斷函數處理流程
      • • (1)、irq_handler宏
        • (2)、arch_irq_handler_default 宏
        • (3)、調用了asm_do_IRQ
      • 2、linux kernel arm64的中斷函數處理流程
      • • (1)、irq_handler宏 調用handle_arch_irq
        • (2)、handle_arch_irq
        • (3)、gic_handle_irq()
        • (4)、handle_domain_irq()---->__handle_domain_irq()---->generic_handle_irq()---->generic_handle_irq_desc()

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1、linux kernel arm32的中斷函數處理流程

我們從irq_handler宏函數看起

(1)、irq_handler宏

注意CONFIG_MULTI_IRQ_HANDLER宏表示"允許每臺機器在運行時指定它自己的IRQ處理程序"，當前默認是不開啟的.
所以走else的arch_irq_handler_default邏輯

(arch/arm/kernel/entry-armV.S) /** Interrupt handling.*/.macro irq_handler #ifdef CONFIG_MULTI_IRQ_HANDLERldr r1, =handle_arch_irqmov r0, spbadr lr, 9997fldr pc, [r1] #elsearch_irq_handler_default #endif 9997:.endm

(2)、arch_irq_handler_default 宏

arch_irq_handler_default 宏 調用了asm_do_IRQ或do_IPI

(arch/arm/include/asr/entry-macro-multi.S) /** Interrupt handling. Preserves r7, r8, r9*/.macro arch_irq_handler_defaultget_irqnr_preamble r6, lr 1: get_irqnr_and_base r0, r2, r6, lrmovne r1, sp@@ routine called with r0 = irq number, r1 = struct pt_regs *@badrne lr, 1bbne asm_do_IRQ#ifdef CONFIG_SMP/** XXX** this macro assumes that irqstat (r2) and base (r6) are* preserved from get_irqnr_and_base above*/ALT_SMP(test_for_ipi r0, r2, r6, lr)ALT_UP_B(9997f)movne r1, spbadrne lr, 1bbne do_IPI #endif 9997:.endm

(3)、調用了asm_do_IRQ

asm_do_IRQ()—>handle_IRQ()—>__handle_domain_irq()—>generic_handle_irq()—>調用用戶request_irq注冊的中斷處理函數

void handle_IRQ(unsigned int irq, struct pt_regs *regs) {__handle_domain_irq(NULL, irq, false, regs); } /** asm_do_IRQ is the interface to be used from assembly code.*/ asmlinkage void __exception_irq_entry asm_do_IRQ(unsigned int irq, struct pt_regs *regs) {handle_IRQ(irq, regs); } int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq,bool lookup, struct pt_regs *regs) {struct pt_regs *old_regs = set_irq_regs(regs);unsigned int irq = hwirq;int ret = 0;irq_enter();#ifdef CONFIG_IRQ_DOMAINif (lookup)irq = irq_find_mapping(domain, hwirq); #endif/** Some hardware gives randomly wrong interrupts. Rather* than crashing, do something sensible.*/if (unlikely(!irq || irq >= nr_irqs)) {ack_bad_irq(irq);ret = -EINVAL;} else {generic_handle_irq(irq);}irq_exit();set_irq_regs(old_regs);return ret; } (kernel/irq/irqdesc.c) int generic_handle_irq(unsigned int irq) {struct irq_desc *desc = irq_to_desc(irq);if (!desc)return -EINVAL;generic_handle_irq_desc(desc);return 0; } EXPORT_SYMBOL_GPL(generic_handle_irq); (kernel/include/linux/irqdesc.h) static inline void generic_handle_irq_desc(struct irq_desc *desc) {desc->handle_irq(desc); // 這里真正調用到，用戶request_irq注冊的中斷處理函數 }

2、linux kernel arm64的中斷函數處理流程

我們依然從irq_handler宏函數看起

(1)、irq_handler宏 調用handle_arch_irq

(arch/arm/kernel/entry.S) /** Interrupt handling.*/.macro irq_handlerldr_l x1, handle_arch_irqmov x0, spirq_stack_entryblr x1irq_stack_exit.endm

(2)、handle_arch_irq

handle_arch_irq是在set_handle_irq()設置的handle地址

void __init set_handle_irq(void (*handle_irq)(struct pt_regs *)) {if (handle_arch_irq)return;handle_arch_irq = handle_irq; }

(3)、gic_handle_irq()

在gic_of_init初始化的時候，將gic_handle_irq()地址賦給了handle_arch_irq

static int __init gic_of_init(struct device_node *node, struct device_node *parent) { ......set_handle_irq(gic_handle_irq); ...... }

進入gic中的gic_handle_irq處理函數
在這里會調用handle_domain_irq函數或者handle_IPI函數

static asmlinkage void __exception_irq_entry gic_handle_irq(struct pt_regs *regs) {u32 irqnr;do {irqnr = gic_read_iar();if (likely(irqnr > 15 && irqnr < 1020) || irqnr >= 8192) {int err;if (static_key_true(&supports_deactivate))gic_write_eoir(irqnr);err = handle_domain_irq(gic_data.domain, irqnr, regs);if (err) {WARN_ONCE(true, "Unexpected interrupt received!\n");if (static_key_true(&supports_deactivate)) {if (irqnr < 8192)gic_write_dir(irqnr);} else {gic_write_eoir(irqnr);}}continue;}if (irqnr < 16) {gic_write_eoir(irqnr);if (static_key_true(&supports_deactivate))gic_write_dir(irqnr); #ifdef CONFIG_SMP/** Unlike GICv2, we don't need an smp_rmb() here.* The control dependency from gic_read_iar to* the ISB in gic_write_eoir is enough to ensure* that any shared data read by handle_IPI will* be read after the ACK.*/handle_IPI(irqnr, regs); #elseWARN_ONCE(true, "Unexpected SGI received!\n"); #endifcontinue;}} while (irqnr != ICC_IAR1_EL1_SPURIOUS); }

(4)、handle_domain_irq()---->__handle_domain_irq()---->generic_handle_irq()---->generic_handle_irq_desc()

int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq,bool lookup, struct pt_regs *regs) {struct pt_regs *old_regs = set_irq_regs(regs);unsigned int irq = hwirq;int ret = 0;irq_enter();#ifdef CONFIG_IRQ_DOMAINif (lookup)irq = irq_find_mapping(domain, hwirq); #endif/** Some hardware gives randomly wrong interrupts. Rather* than crashing, do something sensible.*/if (unlikely(!irq || irq >= nr_irqs)) {ack_bad_irq(irq);ret = -EINVAL;} else {generic_handle_irq(irq);}irq_exit();set_irq_regs(old_regs);return ret; } int generic_handle_irq(unsigned int irq) {struct irq_desc *desc = irq_to_desc(irq);if (!desc)return -EINVAL;generic_handle_irq_desc(desc);return 0; } EXPORT_SYMBOL_GPL(generic_handle_irq);static inline void generic_handle_irq_desc(struct irq_desc *desc) {desc->handle_irq(desc); }

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