![\"\"](\"http:\/\/pareto.fun\/wp-content\/uploads\/2020\/10\/image002-12.gif\")
<\/figure>\n\n\n\nhttps:\/\/book.aikaiyuan.com\/kernel\/3.1.4.htm<\/a><\/p>\n\n\n\n \u4e3b\u8981\u8bb2\u56db\u4e2a\u5b57\u6bb5,\u95e8\u7c7b\u578b , \u4e2d\u65ad\u53f7 , \u8df3\u8f6c\u5730\u5740 DPI<\/p>\n\n\n\n intel\u63d0\u4f9b\u4e09\u79cd\u95e8\u7c7b\u578b:<\/p>\n\n\n\n \u5b9e\u9645\u4e0alinux\u63d0\u4f9b\u4e86\u4e94\u79cd\u95e8:<\/p>\n\n\n\n \u7b80\u5355\u8bf4\u5c31\u662f\u4e2d\u65ad\u53f7\u4e3a0x80 \u7684\u8f6f\u4e2d\u65ad. \u5165\u53e3\u51fd\u6570\u4fdd\u5b58\u73b0\u573a\uff0c\u8c03\u7528\u8c03\u7528\u53f7\u7684\u5730\u5740\uff0c\u7ed3\u675f\u540e\u8fd8\u539f\u73b0\u573a\u3002<\/p>\n\n\n\n \u5185\u6838\u5728\u542f\u52a8\u65f6\uff0c\u5728trap_init\u8fc7\u7a0b\u4e2d\u5bf9\u53ef\u7f16\u7a0b\u4e2d\u65ad\u63a7\u5236\u5668(pic)\u8fdb\u884c\u521d\u59cb\u5316\u786e\u5b9a\u4e2d\u65ad\u77e2\u91cf\u8c03\u7528\u7684\u5730\u5740\u3002<\/p>\n\n\n\n \u521d\u59cb\u5316\u8fc7\u7a0b\u7ed3\u675f\u540e\uff0c\u5f53\u8fd9\u53d1\u751f\u4e2d\u65ad\u77e2\u91cf\u4e3a0x80\u65f6\uff0c\u5c31\u4f1a\u8df3\u8f6c\u5230entry_INT80_compat\u5165\u53e3\u51fd\u6570\u53bb\uff0c\u8fd9\u4e2a\u8df3\u8f6c\u7684\u8fc7\u7a0b\u7531\u53ef\u7f16\u7a0b\u4e2d\u65ad\u63a7\u5236\u5668\u5b8c\u6210\u3002set_system_intr_gate \u4e3alinux\u63d0\u4f9b\u7684\u7cfb\u7edf\u4e2d\u65ad\u95e8\uff0c\u5185\u6838\u63d0\u4f9b\u7ed9linux\u7528\u6237\u6001\u7684\u63a5\u53e3\uff0c\u8868\u793a\u7528\u6237\u6001\u7a0b\u5e8f\u4f7f\u7528\u8be5\u4e2d\u65ad\u53f7\u53ef\u4ee5\u8fdb\u5165\u5230\u5185\u6838\u6001\u3002\u4e2d\u65ad\u4e2d\u65ad\u95e8 \u9664\u4e860x80 \u4ee5\u4e3a\u8fd8\u67090x3 \u3002<\/p>\n\n\n\n \u8df3\u8f6c\u5230\u7cfb\u7edf\u8c03\u7528\u5904\u7406\u51fd\u6570\uff0c<\/p>\n\n\n\n \u5df2\u77e5\u4e86\u5176\u4ed6\u51fd\u6570\u7684\u4f5c\u7528\uff0c\u6211\u4eec\u5c31\u628a\u91cd\u5fc3\u653e\u5728wake_up_process() \u4e0a\u3002wake_up_process \u8c03\u7528\u4e86try_to_wake_up() \u51fd\u6570\u8fc7\u7a0b\u3002<\/p>\n\n\n\n wake_up_process() \u8c03\u7528try_to_wake_up(),try_wake_up() \u51fd\u6570\u4f4d\u4e8ekernel\/sched.c<\/strong><\/a><\/p>\n\n\n\n \u8c03\u8bd5\u8fc7\u7a0b\u4e2d\uff0c\u6392\u9664\u5176\u4ed6\u51fd\u6570\uff0c\u5b9a\u4f4d\u5230resched_task() \u51fd\u6570\uff0c\u8fc7\u7a0b\u6d89\u53ca\u5230\u8fdb\u7a0b\u5207\u6362\uff0c\u5f53\u524d\u6c34\u5e73\u4e0d\u591f\uff0c\u5b66\u4e60Task_struct\u540e\u518d\u6765\u5c1d\u8bd5\u3002<\/p>\n\n\n\n https:\/\/blog.csdn.net\/hq815601489\/article\/details\/80009791<\/a> Linux\u7cfb\u7edf\u8c03\u7528\uff1a\u4f7f\u7528int 0x80<\/p> https:\/\/blog.csdn.net\/weixin_33850890\/article\/details\/92823320<\/a> Linux\u7cfb\u7edf\u8c03\u7528\u4e0eptrace\u5206\u6790<\/p>\u7cfb\u7edf\u8c03\u7528<\/h3>\n\n\n\n
\u4e2d\u65ad\u5230\u7cfb\u7edf\u8c03\u7528\u7684\u8fc7\u7a0b<\/h2>\n\n\n\n
void __init trap_init(void)
{
...
#ifdef CONFIG_X86_32
printk(\"CONFIG_X86_32\");
set_system_intr_gate(IA32_SYSCALL_VECTOR, entry_INT80_32);
set_bit(IA32_SYSCALL_VECTOR, used_vectors);
#endif
...
}<\/pre>\n\n\n\nENTRY(entry_INT80_32)
ASM_CLAC
pushl %eax \/* pt_regs->orig_ax *\/
SAVE_ALL pt_regs_ax=$-ENOSYS \/* save rest *\/
\u200b
\/*
* User mode is traced as though IRQs are on, and the interrupt gate
* turned them off.
*\/
TRACE_IRQS_OFF
movl %esp, %eax
call do_int80_syscall_32 #
.Lsyscall_32_done:<\/pre>\n\n\n\n\u200b
\/* Handles int $0x80 *\/
__visible void do_int80_syscall_32(struct pt_regs *regs)
{
enter_from_user_mode();
local_irq_enable(); \/\/\u542f\u7528\u4e2d\u65ad
do_syscall_32_irqs_on(regs); \/\/\u91cd\u70b9
}<\/pre>\n\n\n\nstatic __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
{
struct thread_info *ti = current_thread_info();
unsigned int nr = (unsigned int)regs->orig_ax; \/\/\u83b7\u53d6\u7cfb\u7edf\u8c03\u7528\u53f7
\u200b
#ifdef CONFIG_IA32_EMULATION
current->thread.status |= TS_COMPAT;
#endif
\u200b
if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY) {
\/*
* Subtlety here: if ptrace pokes something larger than
* 2^32-1 into orig_ax, this truncates it. This may or
* may not be necessary, but it matches the old asm
* behavior.
*\/
nr = syscall_trace_enter(regs);
}
\u200b
if (likely(nr < IA32_NR_syscalls)) {
\/*
* It's possible that a 32-bit syscall implementation
* takes a 64-bit parameter but nonetheless assumes that
* the high bits are zero. Make sure we zero-extend all
* of the args.
*\/
\/\/ \u51fd\u6570\u6307\u9488\u8868 \uff0c\u901a\u8fc7nr\u6307\u5230\u8c03\u7528\u7684\u5730\u5740\u3002
regs->ax = ia32_sys_call_table[nr](
(unsigned int)regs->bx, (unsigned int)regs->cx,
(unsigned int)regs->dx, (unsigned int)regs->si,
(unsigned int)regs->di, (unsigned int)regs->bp); \/\/\u4fdd\u5b58\u53c2\u6570\uff0c\u6267\u884c\u7cfb\u7edf\u8c03\u7528
}
\u200b
syscall_return_slowpath(regs);
}
\u200b<\/pre>\n\n\n\nptrace\u8fc7\u7a0b<\/h2>\n\n\n\n
\u51e0\u4e2a\u5173\u952e\u51fd\u6570\u6216\u8005\u5b8f<\/h3>\n\n\n\n
\/*
\u5199\u8005\u4e5f\u53ef\u4ee5\u7528\u5b83\u6765\u83b7\u5f97\u9501\uff0c\u4e0ewrite_lock\u4e0d\u540c\u7684\u662f\uff0c\u8be5\u5b8f\u8fd8\u540c\u65f6\u5931\u6548\u4e86\u672c\u5730\u4e2d\u65ad\u3002\u8be5\u5b8f\u4e0ewrite_lock_irqsave\u7684\u4e0d\u540c\u4e4b\u5904\u662f\uff0c\u5b83\u6ca1\u6709\u4fdd\u5b58\u6807\u5fd7\u5bc4\u5b58\u5668\u3002
*\/
#define write_lock_irq(lock) \\
do { \\
local_irq_disable(); \\
preempt_disable(); \\
_raw_write_lock(lock); \\
} while (0)
\/*
\u200b
*\/
#define write_unlock_irq(lock) \\
do { \\
_raw_write_unlock(lock); \\
local_irq_enable(); \\
preempt_enable(); \\
} while (0)
\/*
\u5c06\u5176\u653e\u4f1a\u5230\u539f\u7236\u8fdb\u7a0b\u4e4b\u4e0b\uff0c\u5e76\u4e14\u4eceptrace list \u5217\u8868\u4e2d\u79fb\u9664
*\/
void __ptrace_unlink(task_t *child)
{
if (!child->ptrace)
BUG();
child->ptrace = 0;
if (list_empty(&child->ptrace_list))
return;
list_del_init(&child->ptrace_list);
REMOVE_LINKS(child);
child->parent = child->real_parent;
SET_LINKS(child);
}
\u200b<\/pre>\n\n\n\nDetach \u8fc7\u7a0b<\/h1>\n\n\n\n
int ptrace_detach(struct task_struct *child, unsigned int data)
{
if ((unsigned long) data > _NSIG)
return -EIO;
\u200b
\/* Architecture-specific hardware disable .. *\/
ptrace_disable(child);
\u200b
\/* .. re-parent .. *\/
child->exit_code = data;
\u200b
write_lock_irq(&tasklist_lock);
__ptrace_unlink(child);
\/* .. and wake it up. *\/
if (child->state != TASK_ZOMBIE)
wake_up_process(child);
write_unlock_irq(&tasklist_lock);
\u200b
return 0;
}<\/pre>\n\n\n\nstatic int try_to_wake_up(task_t * p, unsigned int state, int sync)
{
unsigned long flags;
int success = 0;
long old_state;
runqueue_t *rq;
\u200b
repeat_lock_task:
\/\/\u7981\u6b62\u672c\u5730\u4e2d\u65ad
rq = task_rq_lock(p, &flags);
old_state = p->state;
if (old_state & state) {
\/\/\u5982\u679cp->array\u5b57\u6bb5\u4e0d\u7b49\u4e8eNULL\uff0c\u90a3\u4e48\u8fdb\u7a0b\u5df2\u7ecf\u5c5e\u4e8e\u67d0\u4e2a\u8fd0\u884c\u961f\u5217
if (!p->array) {
\/*
* Fast-migrate the task if it's not running or runnable
* currently. Do not violate hard affinity.
*\/
if (unlikely(sync && !task_running(rq, p) &&
(task_cpu(p) != smp_processor_id()) &&
cpu_isset(smp_processor_id(), p->cpus_allowed))) {
\u200b
set_task_cpu(p, smp_processor_id());
task_rq_unlock(rq, &flags);
goto repeat_lock_task;
}
\/\/\u8fdb\u7a0b\u5904\u4e8e\u4e0d\u53ef\u4e2d\u65ad\u72b6\u6001\u3002
if (old_state == TASK_UNINTERRUPTIBLE){
rq->nr_uninterruptible--;
\/*
* Tasks on involuntary sleep don't earn
* sleep_avg beyond just interactive state.
*\/
p->activated = -1;
}
if (sync && (task_cpu(p) == smp_processor_id()))
__activate_task(p, rq);
else {
activate_task(p, rq);
if (TASK_PREEMPTS_CURR(p, rq))
resched_task(rq->curr);
}
success = 1;
}
p->state = TASK_RUNNING;
}
task_rq_unlock(rq, &flags);
\u200b
return success;
}<\/pre>\n\n\n\n