feat: input device subsystem to resolve race condition on polling input

[lunaix-os.git] / lunaix-os / kernel / sched.c

diff --git a/lunaix-os/kernel/sched.c b/lunaix-os/kernel/sched.c
index ed2cc74a2b02b813d9578d81af5eb36b88774d6c..2274238061df347181a092c2008b560d2af46ddf 100644 (file)
--- a/lunaix-os/kernel/sched.c
+++ b/lunaix-os/kernel/sched.c
@@ -1,120 +1,383 @@
-#include <lunaix/process.h>
-#include <lunaix/sched.h>
-#include <lunaix/mm/vmm.h>
-#include <hal/cpu.h>

 #include <arch/x86/interrupts.h>
 #include <arch/x86/interrupts.h>

+#include <arch/x86/tss.h>
+

 #include <hal/apic.h>
 #include <hal/apic.h>

+#include <hal/cpu.h>

 
 

+#include <lunaix/mm/kalloc.h>
+#include <lunaix/mm/pmm.h>
+#include <lunaix/mm/valloc.h>
+#include <lunaix/mm/vmm.h>
+#include <lunaix/process.h>
+#include <lunaix/sched.h>
+#include <lunaix/signal.h>

 #include <lunaix/spike.h>
 #include <lunaix/status.h>
 #include <lunaix/spike.h>
 #include <lunaix/status.h>

+#include <lunaix/syscall.h>

 #include <lunaix/syslog.h>
 
 #define MAX_PROCESS 512
 
 #include <lunaix/syslog.h>
 
 #define MAX_PROCESS 512
 

-struct proc_info* __current;
-struct proc_info dummy;
+volatile struct proc_info* __current;

 
 

-extern void __proc_table;
+struct proc_info dummy;

 
 struct scheduler sched_ctx;
 
 LOG_MODULE("SCHED")
 
 
 struct scheduler sched_ctx;
 
 LOG_MODULE("SCHED")
 

-void sched_init() {
+void
+sched_init()
+{

     size_t pg_size = ROUNDUP(sizeof(struct proc_info) * MAX_PROCESS, 0x1000);
     size_t pg_size = ROUNDUP(sizeof(struct proc_info) * MAX_PROCESS, 0x1000);

-    assert_msg(
-        vmm_alloc_pages(KERNEL_PID, &__proc_table, pg_size, PG_PREM_RW, PP_FGPERSIST), 
-        "Fail to allocate proc table"
-    );
-    
-    sched_ctx = (struct scheduler) {
-        ._procs = (struct proc_info*) &__proc_table,
-        .ptable_len = 0,
-        .procs_index = 0
-    };

 
 

-    __current = &dummy;
+    for (size_t i = 0; i <= pg_size; i += 4096) {
+        uintptr_t pa = pmm_alloc_page(KERNEL_PID, PP_FGPERSIST);
+        vmm_set_mapping(
+          PD_REFERENCED, PROC_START + i, pa, PG_PREM_RW, VMAP_NULL);
+    }
+
+    sched_ctx = (struct scheduler){ ._procs = (struct proc_info*)PROC_START,
+                                    .ptable_len = 0,
+                                    .procs_index = 0 };
+}
+
+void
+run(struct proc_info* proc)
+{
+    proc->state = PS_RUNNING;
+
+    /*
+        将tss.esp0设置为上次调度前的esp值。
+        当处理信号时，上下文信息是不会恢复的，而是保存在用户栈中，然后直接跳转进位于用户空间的sig_wrapper进行
+          信号的处理。当用户自定义的信号处理函数返回时，sigreturn的系统调用才开始进行上下文的恢复（或者说是进行
+          另一次调度。
+        由于这中间没有进行地址空间的交换，所以第二次跳转使用的是同一个内核栈，而之前默认tss.esp0的值是永远指向最顶部
+        这样一来就有可能会覆盖更早的上下文信息（比如嵌套的信号捕获函数）
+    */
+    tss_update_esp(proc->intr_ctx.registers.esp);
+
+    apic_done_servicing();
+
+    asm volatile("pushl %0\n"
+                 "jmp switch_to\n" ::"r"(proc)
+                 : "memory"); // kernel/asm/x86/interrupt.S
+}
+
+int
+can_schedule(struct proc_info* proc)
+{
+    if (__SIGTEST(proc->sig_pending, _SIGCONT)) {
+        __SIGCLEAR(proc->sig_pending, _SIGSTOP);
+    } else if (__SIGTEST(proc->sig_pending, _SIGSTOP)) {
+        // 如果进程受到SIGSTOP，则该进程不给予调度。
+        return 0;
+    }
+
+    return 1;
+}
+
+void
+check_sleepers()
+{
+    struct proc_info* leader = &sched_ctx._procs[0];
+    struct proc_info *pos, *n;
+    time_t now = clock_systime();
+    llist_for_each(pos, n, &leader->sleep.sleepers, sleep.sleepers)
+    {
+        if (PROC_TERMINATED(pos->state)) {
+            goto del;
+        }
+
+        time_t wtime = pos->sleep.wakeup_time;
+        time_t atime = pos->sleep.alarm_time;
+
+        if (wtime && now >= wtime) {
+            pos->sleep.wakeup_time = 0;
+            pos->state = PS_READY;
+        }
+
+        if (atime && now >= atime) {
+            pos->sleep.alarm_time = 0;
+            __SIGSET(pos->sig_pending, _SIGALRM);
+        }
+
+        if (!wtime && !atime) {
+        del:
+            llist_delete(&pos->sleep.sleepers);
+        }
+    }

 }
 
 }
 

-void schedule() {
+void
+schedule()
+{

     if (!sched_ctx.ptable_len) {
         return;
     }
 
     if (!sched_ctx.ptable_len) {
         return;
     }
 

+    // 上下文切换相当的敏感！我们不希望任何的中断打乱栈的顺序……
+    cpu_disable_interrupt();

     struct proc_info* next;
     int prev_ptr = sched_ctx.procs_index;
     int ptr = prev_ptr;
     struct proc_info* next;
     int prev_ptr = sched_ctx.procs_index;
     int ptr = prev_ptr;

+
+    if (!(__current->state & ~PS_RUNNING)) {
+        __current->state = PS_READY;
+    }
+
+    check_sleepers();
+

     // round-robin scheduler
     // round-robin scheduler

+redo:

     do {
         ptr = (ptr + 1) % sched_ctx.ptable_len;
         next = &sched_ctx._procs[ptr];
     do {
         ptr = (ptr + 1) % sched_ctx.ptable_len;
         next = &sched_ctx._procs[ptr];

-    } while((next->state != PROC_STOPPED && next->state != PROC_CREATED) && ptr != prev_ptr);
-    
+    } while (next->state != PS_READY && ptr != prev_ptr);
+

     sched_ctx.procs_index = ptr;
     sched_ctx.procs_index = ptr;

-    
-    __current->state = PROC_STOPPED;
-    next->state = PROC_RUNNING;
-    
-    __current = next;

 
 

-    cpu_lcr3(__current->page_table);
+    if (!can_schedule(next)) {
+        // 如果该进程不给予调度，则尝试重新选择
+        goto redo;
+    }

 
 

-    apic_done_servicing();
+    run(next);
+}
+
+void
+sched_yieldk()
+{
+    cpu_enable_interrupt();
+    cpu_int(LUNAIX_SCHED);
+}
+
+__DEFINE_LXSYSCALL1(unsigned int, sleep, unsigned int, seconds)
+{
+    if (!seconds) {
+        return 0;
+    }
+
+    if (__current->sleep.wakeup_time) {
+        return (__current->sleep.wakeup_time - clock_systime()) / 1000U;
+    }
+
+    __current->sleep.wakeup_time = clock_systime() + seconds * 1000;
+    llist_append(&sched_ctx._procs[0].sleep.sleepers,
+                 &__current->sleep.sleepers);
+
+    __current->intr_ctx.registers.eax = seconds;
+    __current->state = PS_BLOCKED;
+    schedule();
+}
+
+__DEFINE_LXSYSCALL1(unsigned int, alarm, unsigned int, seconds)
+{
+    time_t prev_ddl = __current->sleep.alarm_time;
+    time_t now = clock_systime();
+
+    __current->sleep.alarm_time = seconds ? now + seconds * 1000 : 0;

 
 

-    asm volatile ("pushl %0\n jmp soft_iret\n"::"r"(&__current->intr_ctx): "memory");
+    if (llist_empty(&__current->sleep.sleepers)) {
+        llist_append(&sched_ctx._procs[0].sleep.sleepers,
+                     &__current->sleep.sleepers);
+    }
+
+    return prev_ddl ? (prev_ddl - now) / 1000 : 0;
+}
+
+__DEFINE_LXSYSCALL1(void, exit, int, status)
+{
+    terminate_proc(status);
+    schedule();
+}
+
+__DEFINE_LXSYSCALL(void, yield)
+{
+    schedule();
+}
+
+pid_t
+_wait(pid_t wpid, int* status, int options);
+
+__DEFINE_LXSYSCALL1(pid_t, wait, int*, status)
+{
+    return _wait(-1, status, 0);
+}
+
+__DEFINE_LXSYSCALL3(pid_t, waitpid, pid_t, pid, int*, status, int, options)
+{
+    return _wait(pid, status, options);

 }
 
 }
 

-pid_t alloc_pid() {
+__DEFINE_LXSYSCALL(int, geterrno)
+{
+    return __current->k_status;
+}
+
+pid_t
+_wait(pid_t wpid, int* status, int options)
+{
+    pid_t cur = __current->pid;
+    int status_flags = 0;
+    struct proc_info *proc, *n;
+    if (llist_empty(&__current->children)) {
+        return -1;
+    }
+
+    wpid = wpid ? wpid : -__current->pgid;
+repeat:
+    llist_for_each(proc, n, &__current->children, siblings)
+    {
+        if (!~wpid || proc->pid == wpid || proc->pgid == -wpid) {
+            if (proc->state == PS_TERMNAT && !options) {
+                status_flags |= PEXITTERM;
+                goto done;
+            }
+            if (proc->state == PS_READY && (options & WUNTRACED)) {
+                status_flags |= PEXITSTOP;
+                goto done;
+            }
+        }
+    }
+    if ((options & WNOHANG)) {
+        return 0;
+    }
+    // 放弃当前的运行机会
+    sched_yieldk();
+    goto repeat;
+
+done:
+    status_flags |= PEXITSIG * (proc->sig_inprogress != 0);
+    if (status) {
+        *status = proc->exit_code | status_flags;
+    }
+    return destroy_process(proc->pid);
+}
+
+struct proc_info*
+alloc_process()
+{

     pid_t i = 0;
     pid_t i = 0;

-    for (; i < sched_ctx.ptable_len && sched_ctx._procs[i].state != PROC_DESTROY; i++);
+    for (; i < sched_ctx.ptable_len && sched_ctx._procs[i].state != PS_DESTROY;
+         i++)
+        ;

 
     if (i == MAX_PROCESS) {
 
     if (i == MAX_PROCESS) {

-        __current->k_status = LXPROCFULL;
-        return -1;
+        panick("Panic in Ponyville shimmer!");

     }
     }

-    return i + 1;
+
+    if (i == sched_ctx.ptable_len) {
+        sched_ctx.ptable_len++;
+    }
+
+    struct proc_info* proc = &sched_ctx._procs[i];
+    memset(proc, 0, sizeof(*proc));
+
+    proc->state = PS_CREATED;
+    proc->pid = i;
+    proc->created = clock_systime();
+    proc->pgid = proc->pid;
+    proc->fdtable = vzalloc(sizeof(struct v_fdtable));
+
+    llist_init_head(&proc->mm.regions.head);
+    llist_init_head(&proc->children);
+    llist_init_head(&proc->grp_member);
+    llist_init_head(&proc->sleep.sleepers);
+    waitq_init(&proc->waitqueue);
+
+    return proc;

 }
 
 }
 

-void push_process(struct proc_info* process) {
-    int index = process->pid - 1;
-    if (index < 0 || index > sched_ctx.ptable_len) {
-        __current->k_status = LXINVLDPID;
+void
+commit_process(struct proc_info* process)
+{
+    assert(process == &sched_ctx._procs[process->pid]);
+
+    if (process->state != PS_CREATED) {
+        __current->k_status = EINVAL;

         return;
     }
         return;
     }

-    
-    if (index == sched_ctx.ptable_len) {
-        sched_ctx.ptable_len++;
+
+    // every process is the child of first process (pid=1)
+    if (!process->parent) {
+        process->parent = &sched_ctx._procs[1];

     }
     }

-    
-    process->parent = __current->pid;
-    process->state = PROC_CREATED;

 
 

-    sched_ctx._procs[index] = *process;
+    llist_append(&process->parent->children, &process->siblings);
+
+    process->state = PS_READY;

 }
 
 }
 

-void destroy_process(pid_t pid) {
-    int index = pid - 1;
-    if (index < 0 || index > sched_ctx.ptable_len) {
-        __current->k_status = LXINVLDPID;
+// from <kernel/process.c>
+extern void
+__del_pagetable(pid_t pid, uintptr_t mount_point);
+
+pid_t
+destroy_process(pid_t pid)
+{
+    int index = pid;
+    if (index <= 0 || index > sched_ctx.ptable_len) {
+        __current->k_status = EINVAL;

         return;
     }
         return;
     }

+    struct proc_info* proc = &sched_ctx._procs[index];
+    proc->state = PS_DESTROY;
+    llist_delete(&proc->siblings);
+
+    for (size_t i = 0; i < VFS_MAX_FD; i++) {
+        struct v_fd* fd = proc->fdtable->fds[i];
+        if (fd)
+            vfs_close(fd->file);
+    }
+
+    vfree(proc->fdtable);
+
+    struct mm_region *pos, *n;
+    llist_for_each(pos, n, &proc->mm.regions.head, head)
+    {
+        vfree(pos);
+    }

 
 

-    sched_ctx._procs[index].state = PROC_DESTROY;
+    vmm_mount_pd(PD_MOUNT_1, proc->page_table);

 
 

-    // TODO: recycle the physical pages used by page tables
+    __del_pagetable(pid, PD_MOUNT_1);
+
+    vmm_unmount_pd(PD_MOUNT_1);
+
+    return pid;

 }
 
 }
 

-void terminate_process(int exit_code) {
-    __current->state = PROC_TERMNAT;
+void
+terminate_proc(int exit_code)
+{
+    __current->state = PS_TERMNAT;

     __current->exit_code = exit_code;
 
     __current->exit_code = exit_code;
 

-    schedule();
+    __SIGSET(__current->parent->sig_pending, _SIGCHLD);

 }
 
 }
 

-struct proc_info* get_process(pid_t pid) {
-    int index = pid - 1;
+struct proc_info*
+get_process(pid_t pid)
+{
+    int index = pid;

     if (index < 0 || index > sched_ctx.ptable_len) {
         return NULL;
     }
     return &sched_ctx._procs[index];
     if (index < 0 || index > sched_ctx.ptable_len) {
         return NULL;
     }
     return &sched_ctx._procs[index];

+}
+
+int
+orphaned_proc(pid_t pid)
+{
+    if (!pid)
+        return 0;
+    if (pid >= sched_ctx.ptable_len)
+        return 0;
+    struct proc_info* proc = &sched_ctx._procs[pid];
+    struct proc_info* parent = proc->parent;
+
+    // 如果其父进程的状态是terminated 或 destroy中的一种
+    // 或者其父进程是在该进程之后创建的，那么该进程为孤儿进程
+    return PROC_TERMINATED(parent->state) || parent->created > proc->created;

 }
\ No newline at end of file
 }
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