Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | * Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar |
| 3 | * |
| 4 | * This file contains the lowest level x86-specific interrupt |
| 5 | * entry, irq-stacks and irq statistics code. All the remaining |
| 6 | * irq logic is done by the generic kernel/irq/ code and |
| 7 | * by the x86-specific irq controller code. (e.g. i8259.c and |
| 8 | * io_apic.c.) |
| 9 | */ |
| 10 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 11 | #include <linux/module.h> |
| 12 | #include <linux/seq_file.h> |
| 13 | #include <linux/interrupt.h> |
| 14 | #include <linux/kernel_stat.h> |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 15 | #include <linux/notifier.h> |
| 16 | #include <linux/cpu.h> |
| 17 | #include <linux/delay.h> |
Jaswinder Singh Rajput | 72ade5f | 2009-01-04 16:32:36 +0530 | [diff] [blame] | 18 | #include <linux/uaccess.h> |
Lai Jiangshan | 42f8fae | 2009-02-17 11:46:42 +0800 | [diff] [blame] | 19 | #include <linux/percpu.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | |
Thomas Gleixner | e05d723 | 2007-02-16 01:27:58 -0800 | [diff] [blame] | 21 | #include <asm/apic.h> |
Thomas Gleixner | e05d723 | 2007-02-16 01:27:58 -0800 | [diff] [blame] | 22 | |
Fenghua Yu | f34e3b6 | 2007-07-19 01:48:13 -0700 | [diff] [blame] | 23 | DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | EXPORT_PER_CPU_SYMBOL(irq_stat); |
| 25 | |
Jeremy Fitzhardinge | 7c3576d | 2007-05-02 19:27:16 +0200 | [diff] [blame] | 26 | DEFINE_PER_CPU(struct pt_regs *, irq_regs); |
| 27 | EXPORT_PER_CPU_SYMBOL(irq_regs); |
| 28 | |
Thomas Gleixner | de9b10a | 2008-05-05 15:58:15 +0200 | [diff] [blame] | 29 | #ifdef CONFIG_DEBUG_STACKOVERFLOW |
| 30 | /* Debugging check for stack overflow: is there less than 1KB free? */ |
| 31 | static int check_stack_overflow(void) |
| 32 | { |
| 33 | long sp; |
| 34 | |
| 35 | __asm__ __volatile__("andl %%esp,%0" : |
| 36 | "=r" (sp) : "0" (THREAD_SIZE - 1)); |
| 37 | |
| 38 | return sp < (sizeof(struct thread_info) + STACK_WARN); |
| 39 | } |
| 40 | |
| 41 | static void print_stack_overflow(void) |
| 42 | { |
| 43 | printk(KERN_WARNING "low stack detected by irq handler\n"); |
| 44 | dump_stack(); |
| 45 | } |
| 46 | |
| 47 | #else |
| 48 | static inline int check_stack_overflow(void) { return 0; } |
| 49 | static inline void print_stack_overflow(void) { } |
| 50 | #endif |
| 51 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | #ifdef CONFIG_4KSTACKS |
| 53 | /* |
| 54 | * per-CPU IRQ handling contexts (thread information and stack) |
| 55 | */ |
| 56 | union irq_ctx { |
| 57 | struct thread_info tinfo; |
| 58 | u32 stack[THREAD_SIZE/sizeof(u32)]; |
Lai Jiangshan | 42f8fae | 2009-02-17 11:46:42 +0800 | [diff] [blame] | 59 | } __attribute__((aligned(PAGE_SIZE))); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 60 | |
Lai Jiangshan | 42f8fae | 2009-02-17 11:46:42 +0800 | [diff] [blame] | 61 | static DEFINE_PER_CPU(union irq_ctx *, hardirq_ctx); |
| 62 | static DEFINE_PER_CPU(union irq_ctx *, softirq_ctx); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | |
Lai Jiangshan | 42f8fae | 2009-02-17 11:46:42 +0800 | [diff] [blame] | 64 | static DEFINE_PER_CPU_PAGE_ALIGNED(union irq_ctx, hardirq_stack); |
| 65 | static DEFINE_PER_CPU_PAGE_ALIGNED(union irq_ctx, softirq_stack); |
Thomas Gleixner | 403d8ef | 2008-05-05 18:13:50 +0200 | [diff] [blame] | 66 | |
| 67 | static void call_on_stack(void *func, void *stack) |
| 68 | { |
| 69 | asm volatile("xchgl %%ebx,%%esp \n" |
| 70 | "call *%%edi \n" |
| 71 | "movl %%ebx,%%esp \n" |
| 72 | : "=b" (stack) |
| 73 | : "0" (stack), |
| 74 | "D"(func) |
| 75 | : "memory", "cc", "edx", "ecx", "eax"); |
Andi Kleen | 04b361a | 2008-05-05 12:36:38 +0200 | [diff] [blame] | 76 | } |
| 77 | |
Thomas Gleixner | de9b10a | 2008-05-05 15:58:15 +0200 | [diff] [blame] | 78 | static inline int |
| 79 | execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq) |
| 80 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | union irq_ctx *curctx, *irqctx; |
Thomas Gleixner | 403d8ef | 2008-05-05 18:13:50 +0200 | [diff] [blame] | 82 | u32 *isp, arg1, arg2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 83 | |
| 84 | curctx = (union irq_ctx *) current_thread_info(); |
Lai Jiangshan | 42f8fae | 2009-02-17 11:46:42 +0800 | [diff] [blame] | 85 | irqctx = __get_cpu_var(hardirq_ctx); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | |
| 87 | /* |
| 88 | * this is where we switch to the IRQ stack. However, if we are |
| 89 | * already using the IRQ stack (because we interrupted a hardirq |
| 90 | * handler) we can't do that and just have to keep using the |
| 91 | * current stack (which is the irq stack already after all) |
| 92 | */ |
Thomas Gleixner | de9b10a | 2008-05-05 15:58:15 +0200 | [diff] [blame] | 93 | if (unlikely(curctx == irqctx)) |
| 94 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 95 | |
Thomas Gleixner | de9b10a | 2008-05-05 15:58:15 +0200 | [diff] [blame] | 96 | /* build the stack frame on the IRQ stack */ |
Jaswinder Singh Rajput | 72ade5f | 2009-01-04 16:32:36 +0530 | [diff] [blame] | 97 | isp = (u32 *) ((char *)irqctx + sizeof(*irqctx)); |
Thomas Gleixner | de9b10a | 2008-05-05 15:58:15 +0200 | [diff] [blame] | 98 | irqctx->tinfo.task = curctx->tinfo.task; |
| 99 | irqctx->tinfo.previous_esp = current_stack_pointer; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 100 | |
Thomas Gleixner | de9b10a | 2008-05-05 15:58:15 +0200 | [diff] [blame] | 101 | /* |
| 102 | * Copy the softirq bits in preempt_count so that the |
| 103 | * softirq checks work in the hardirq context. |
| 104 | */ |
| 105 | irqctx->tinfo.preempt_count = |
| 106 | (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) | |
| 107 | (curctx->tinfo.preempt_count & SOFTIRQ_MASK); |
Björn Steinbrink | a5d157e | 2006-06-25 16:24:40 +0200 | [diff] [blame] | 108 | |
Thomas Gleixner | de9b10a | 2008-05-05 15:58:15 +0200 | [diff] [blame] | 109 | if (unlikely(overflow)) |
Thomas Gleixner | 403d8ef | 2008-05-05 18:13:50 +0200 | [diff] [blame] | 110 | call_on_stack(print_stack_overflow, isp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 111 | |
Thomas Gleixner | 403d8ef | 2008-05-05 18:13:50 +0200 | [diff] [blame] | 112 | asm volatile("xchgl %%ebx,%%esp \n" |
| 113 | "call *%%edi \n" |
| 114 | "movl %%ebx,%%esp \n" |
| 115 | : "=a" (arg1), "=d" (arg2), "=b" (isp) |
| 116 | : "0" (irq), "1" (desc), "2" (isp), |
| 117 | "D" (desc->handle_irq) |
| 118 | : "memory", "cc", "ecx"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 119 | return 1; |
| 120 | } |
| 121 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 122 | /* |
| 123 | * allocate per-cpu stacks for hardirq and for softirq processing |
| 124 | */ |
Thomas Gleixner | 403d8ef | 2008-05-05 18:13:50 +0200 | [diff] [blame] | 125 | void __cpuinit irq_ctx_init(int cpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | { |
| 127 | union irq_ctx *irqctx; |
| 128 | |
Lai Jiangshan | 42f8fae | 2009-02-17 11:46:42 +0800 | [diff] [blame] | 129 | if (per_cpu(hardirq_ctx, cpu)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | return; |
| 131 | |
Lai Jiangshan | 42f8fae | 2009-02-17 11:46:42 +0800 | [diff] [blame] | 132 | irqctx = &per_cpu(hardirq_stack, cpu); |
Thomas Gleixner | 403d8ef | 2008-05-05 18:13:50 +0200 | [diff] [blame] | 133 | irqctx->tinfo.task = NULL; |
| 134 | irqctx->tinfo.exec_domain = NULL; |
| 135 | irqctx->tinfo.cpu = cpu; |
| 136 | irqctx->tinfo.preempt_count = HARDIRQ_OFFSET; |
| 137 | irqctx->tinfo.addr_limit = MAKE_MM_SEG(0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 138 | |
Lai Jiangshan | 42f8fae | 2009-02-17 11:46:42 +0800 | [diff] [blame] | 139 | per_cpu(hardirq_ctx, cpu) = irqctx; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 140 | |
Lai Jiangshan | 42f8fae | 2009-02-17 11:46:42 +0800 | [diff] [blame] | 141 | irqctx = &per_cpu(softirq_stack, cpu); |
Thomas Gleixner | 403d8ef | 2008-05-05 18:13:50 +0200 | [diff] [blame] | 142 | irqctx->tinfo.task = NULL; |
| 143 | irqctx->tinfo.exec_domain = NULL; |
| 144 | irqctx->tinfo.cpu = cpu; |
| 145 | irqctx->tinfo.preempt_count = 0; |
| 146 | irqctx->tinfo.addr_limit = MAKE_MM_SEG(0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 147 | |
Lai Jiangshan | 42f8fae | 2009-02-17 11:46:42 +0800 | [diff] [blame] | 148 | per_cpu(softirq_ctx, cpu) = irqctx; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 149 | |
Thomas Gleixner | 403d8ef | 2008-05-05 18:13:50 +0200 | [diff] [blame] | 150 | printk(KERN_DEBUG "CPU %u irqstacks, hard=%p soft=%p\n", |
Lai Jiangshan | 42f8fae | 2009-02-17 11:46:42 +0800 | [diff] [blame] | 151 | cpu, per_cpu(hardirq_ctx, cpu), per_cpu(softirq_ctx, cpu)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 152 | } |
| 153 | |
Li Shaohua | e1367da | 2005-06-25 14:54:56 -0700 | [diff] [blame] | 154 | void irq_ctx_exit(int cpu) |
| 155 | { |
Lai Jiangshan | 42f8fae | 2009-02-17 11:46:42 +0800 | [diff] [blame] | 156 | per_cpu(hardirq_ctx, cpu) = NULL; |
Li Shaohua | e1367da | 2005-06-25 14:54:56 -0700 | [diff] [blame] | 157 | } |
| 158 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 159 | asmlinkage void do_softirq(void) |
| 160 | { |
| 161 | unsigned long flags; |
| 162 | struct thread_info *curctx; |
| 163 | union irq_ctx *irqctx; |
| 164 | u32 *isp; |
| 165 | |
| 166 | if (in_interrupt()) |
| 167 | return; |
| 168 | |
| 169 | local_irq_save(flags); |
| 170 | |
| 171 | if (local_softirq_pending()) { |
| 172 | curctx = current_thread_info(); |
Lai Jiangshan | 42f8fae | 2009-02-17 11:46:42 +0800 | [diff] [blame] | 173 | irqctx = __get_cpu_var(softirq_ctx); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 174 | irqctx->tinfo.task = curctx->task; |
| 175 | irqctx->tinfo.previous_esp = current_stack_pointer; |
| 176 | |
| 177 | /* build the stack frame on the softirq stack */ |
Jaswinder Singh Rajput | 72ade5f | 2009-01-04 16:32:36 +0530 | [diff] [blame] | 178 | isp = (u32 *) ((char *)irqctx + sizeof(*irqctx)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 | |
Thomas Gleixner | 403d8ef | 2008-05-05 18:13:50 +0200 | [diff] [blame] | 180 | call_on_stack(__do_softirq, isp); |
Ingo Molnar | 55f327f | 2006-07-03 00:24:43 -0700 | [diff] [blame] | 181 | /* |
| 182 | * Shouldnt happen, we returned above if in_interrupt(): |
Thomas Gleixner | 403d8ef | 2008-05-05 18:13:50 +0200 | [diff] [blame] | 183 | */ |
Ingo Molnar | 55f327f | 2006-07-03 00:24:43 -0700 | [diff] [blame] | 184 | WARN_ON_ONCE(softirq_count()); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 185 | } |
| 186 | |
| 187 | local_irq_restore(flags); |
| 188 | } |
Thomas Gleixner | 403d8ef | 2008-05-05 18:13:50 +0200 | [diff] [blame] | 189 | |
Thomas Gleixner | de9b10a | 2008-05-05 15:58:15 +0200 | [diff] [blame] | 190 | #else |
| 191 | static inline int |
| 192 | execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq) { return 0; } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 193 | #endif |
| 194 | |
Jeremy Fitzhardinge | 9b2b76a | 2009-02-06 14:09:40 -0800 | [diff] [blame] | 195 | bool handle_irq(unsigned irq, struct pt_regs *regs) |
| 196 | { |
| 197 | struct irq_desc *desc; |
| 198 | int overflow; |
| 199 | |
| 200 | overflow = check_stack_overflow(); |
| 201 | |
| 202 | desc = irq_to_desc(irq); |
| 203 | if (unlikely(!desc)) |
| 204 | return false; |
| 205 | |
| 206 | if (!execute_on_irq_stack(overflow, desc, irq)) { |
| 207 | if (unlikely(overflow)) |
| 208 | print_stack_overflow(); |
| 209 | desc->handle_irq(irq, desc); |
| 210 | } |
| 211 | |
| 212 | return true; |
| 213 | } |
| 214 | |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 215 | #ifdef CONFIG_HOTPLUG_CPU |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 216 | |
Mike Travis | d7b381b | 2008-12-16 17:33:58 -0800 | [diff] [blame] | 217 | /* A cpu has been removed from cpu_online_mask. Reset irq affinities. */ |
| 218 | void fixup_irqs(void) |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 219 | { |
| 220 | unsigned int irq; |
| 221 | static int warned; |
Yinghai Lu | 199751d | 2008-08-19 20:50:27 -0700 | [diff] [blame] | 222 | struct irq_desc *desc; |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 223 | |
Yinghai Lu | 199751d | 2008-08-19 20:50:27 -0700 | [diff] [blame] | 224 | for_each_irq_desc(irq, desc) { |
Mike Travis | d7b381b | 2008-12-16 17:33:58 -0800 | [diff] [blame] | 225 | const struct cpumask *affinity; |
Yinghai Lu | 08678b0 | 2008-08-19 20:50:05 -0700 | [diff] [blame] | 226 | |
Yinghai Lu | 0b8f1ef | 2008-12-05 18:58:31 -0800 | [diff] [blame] | 227 | if (!desc) |
| 228 | continue; |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 229 | if (irq == 2) |
| 230 | continue; |
| 231 | |
Mike Travis | 7f7ace0 | 2009-01-10 21:58:08 -0800 | [diff] [blame] | 232 | affinity = desc->affinity; |
Mike Travis | d7b381b | 2008-12-16 17:33:58 -0800 | [diff] [blame] | 233 | if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) { |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 234 | printk("Breaking affinity for irq %i\n", irq); |
Mike Travis | d7b381b | 2008-12-16 17:33:58 -0800 | [diff] [blame] | 235 | affinity = cpu_all_mask; |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 236 | } |
Yinghai Lu | 08678b0 | 2008-08-19 20:50:05 -0700 | [diff] [blame] | 237 | if (desc->chip->set_affinity) |
Mike Travis | d7b381b | 2008-12-16 17:33:58 -0800 | [diff] [blame] | 238 | desc->chip->set_affinity(irq, affinity); |
Yinghai Lu | 08678b0 | 2008-08-19 20:50:05 -0700 | [diff] [blame] | 239 | else if (desc->action && !(warned++)) |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 240 | printk("Cannot set affinity for irq %i\n", irq); |
| 241 | } |
| 242 | |
| 243 | #if 0 |
| 244 | barrier(); |
| 245 | /* Ingo Molnar says: "after the IO-APIC masks have been redirected |
| 246 | [note the nop - the interrupt-enable boundary on x86 is two |
| 247 | instructions from sti] - to flush out pending hardirqs and |
| 248 | IPIs. After this point nothing is supposed to reach this CPU." */ |
| 249 | __asm__ __volatile__("sti; nop; cli"); |
| 250 | barrier(); |
| 251 | #else |
| 252 | /* That doesn't seem sufficient. Give it 1ms. */ |
| 253 | local_irq_enable(); |
| 254 | mdelay(1); |
| 255 | local_irq_disable(); |
| 256 | #endif |
| 257 | } |
| 258 | #endif |
| 259 | |