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161 lines
4.0 KiB
161 lines
4.0 KiB
// 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-specific interrupt |
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* entry, irq-stacks and irq statistics code. All the remaining |
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* irq logic is done by the generic kernel/irq/ code and |
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* by the x86-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/seq_file.h> |
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#include <linux/interrupt.h> |
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#include <linux/irq.h> |
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#include <linux/kernel_stat.h> |
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#include <linux/notifier.h> |
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#include <linux/cpu.h> |
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#include <linux/delay.h> |
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#include <linux/uaccess.h> |
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#include <linux/percpu.h> |
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#include <linux/mm.h> |
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#include <asm/apic.h> |
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#include <asm/nospec-branch.h> |
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#include <asm/softirq_stack.h> |
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#ifdef CONFIG_DEBUG_STACKOVERFLOW |
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int sysctl_panic_on_stackoverflow __read_mostly; |
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/* Debugging check for stack overflow: is there less than 1KB free? */ |
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static int check_stack_overflow(void) |
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{ |
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long sp; |
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__asm__ __volatile__("andl %%esp,%0" : |
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"=r" (sp) : "0" (THREAD_SIZE - 1)); |
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return sp < (sizeof(struct thread_info) + STACK_WARN); |
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} |
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static void print_stack_overflow(void) |
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{ |
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printk(KERN_WARNING "low stack detected by irq handler\n"); |
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dump_stack(); |
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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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} |
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#else |
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static inline int check_stack_overflow(void) { return 0; } |
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static inline void print_stack_overflow(void) { } |
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#endif |
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DEFINE_PER_CPU(struct irq_stack *, hardirq_stack_ptr); |
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DEFINE_PER_CPU(struct irq_stack *, softirq_stack_ptr); |
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static void call_on_stack(void *func, void *stack) |
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{ |
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asm volatile("xchgl %%ebx,%%esp \n" |
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CALL_NOSPEC |
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"movl %%ebx,%%esp \n" |
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: "=b" (stack) |
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: "0" (stack), |
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[thunk_target] "D"(func) |
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: "memory", "cc", "edx", "ecx", "eax"); |
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} |
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static inline void *current_stack(void) |
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{ |
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return (void *)(current_stack_pointer & ~(THREAD_SIZE - 1)); |
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} |
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static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc) |
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{ |
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struct irq_stack *curstk, *irqstk; |
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u32 *isp, *prev_esp, arg1; |
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curstk = (struct irq_stack *) current_stack(); |
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irqstk = __this_cpu_read(hardirq_stack_ptr); |
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/* |
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* this is where we switch to the IRQ stack. However, if we are |
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* already using the IRQ stack (because we interrupted a hardirq |
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* handler) we can't do that and just have to keep using the |
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* current stack (which is the irq stack already after all) |
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*/ |
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if (unlikely(curstk == irqstk)) |
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return 0; |
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isp = (u32 *) ((char *)irqstk + sizeof(*irqstk)); |
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/* Save the next esp at the bottom of the stack */ |
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prev_esp = (u32 *)irqstk; |
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*prev_esp = current_stack_pointer; |
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if (unlikely(overflow)) |
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call_on_stack(print_stack_overflow, isp); |
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asm volatile("xchgl %%ebx,%%esp \n" |
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CALL_NOSPEC |
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"movl %%ebx,%%esp \n" |
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: "=a" (arg1), "=b" (isp) |
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: "0" (desc), "1" (isp), |
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[thunk_target] "D" (desc->handle_irq) |
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: "memory", "cc", "ecx"); |
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return 1; |
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} |
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/* |
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* Allocate per-cpu stacks for hardirq and softirq processing |
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*/ |
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int irq_init_percpu_irqstack(unsigned int cpu) |
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{ |
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int node = cpu_to_node(cpu); |
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struct page *ph, *ps; |
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if (per_cpu(hardirq_stack_ptr, cpu)) |
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return 0; |
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ph = alloc_pages_node(node, THREADINFO_GFP, THREAD_SIZE_ORDER); |
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if (!ph) |
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return -ENOMEM; |
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ps = alloc_pages_node(node, THREADINFO_GFP, THREAD_SIZE_ORDER); |
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if (!ps) { |
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__free_pages(ph, THREAD_SIZE_ORDER); |
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return -ENOMEM; |
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} |
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per_cpu(hardirq_stack_ptr, cpu) = page_address(ph); |
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per_cpu(softirq_stack_ptr, cpu) = page_address(ps); |
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return 0; |
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} |
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void do_softirq_own_stack(void) |
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{ |
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struct irq_stack *irqstk; |
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u32 *isp, *prev_esp; |
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irqstk = __this_cpu_read(softirq_stack_ptr); |
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/* build the stack frame on the softirq stack */ |
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isp = (u32 *) ((char *)irqstk + sizeof(*irqstk)); |
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/* Push the previous esp onto the stack */ |
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prev_esp = (u32 *)irqstk; |
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*prev_esp = current_stack_pointer; |
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call_on_stack(__do_softirq, isp); |
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} |
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void __handle_irq(struct irq_desc *desc, struct pt_regs *regs) |
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{ |
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int overflow = check_stack_overflow(); |
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if (user_mode(regs) || !execute_on_irq_stack(overflow, desc)) { |
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if (unlikely(overflow)) |
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print_stack_overflow(); |
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generic_handle_irq_desc(desc); |
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} |
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}
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