Add sched_yield(2)

arch/amd64/syscall.c

@@ -73,6 +73,7 @@ void *syscall_table[256] = {
     // Process control
     [SYSCALL_NRX_SIGENTRY] =        sys_sigentry,
     [SYSCALL_NR_EXECVE] =           sys_execve,
+    [SYSCALL_NR_YIELD] =            sys_yield,
     [SYSCALL_NR_GETPID] =           sys_getpid,
     [SYSCALL_NR_CLONE] =            sys_clone,
     [SYSCALL_NR_KILL] =             sys_kill,

include/sys/sys_proc.h

@@ -19,6 +19,8 @@ int sys_setgid(gid_t gid);
 
 int sys_sigaltstack(const struct user_stack *ss, struct user_stack *old_ss);
 
+void sys_yield(void);
+
 int sys_waitpid(pid_t pid, int *status, int flags);
 pid_t sys_getpgid(pid_t pid);
 int sys_setpgid(pid_t pid, pid_t pgrp);

sys/thread.c

@@ -85,7 +85,6 @@ void proc_add_entry(struct process *proc) {
 
     proc_ensure_dir();
 
-    kdebug("BEGIN ADD ENTRY %d\n", proc->pid);
     snprintf(name, sizeof(name), "%d", proc->pid);
     _assert(sysfs_add_dir(g_sysfs_proc_dir, name, &proc->fs_entry) == 0);
 
@@ -95,15 +94,12 @@ void proc_add_entry(struct process *proc) {
                                       proc, sysfs_proc_parent, NULL) == 0);
     _assert(sysfs_add_config_endpoint(proc->fs_entry, "ioctx", SYSFS_MODE_DEFAULT, 64,
                                       proc, sysfs_proc_ioctx, NULL) == 0);
-    kdebug("END ADD ENTRY %d\n", proc->pid);
 }
 
 void proc_del_entry(struct process *proc) {
     _assert(proc && !(proc->flags & THREAD_KERNEL));
     _assert(proc->pid > 0);
-    kdebug("BEGIN DEL ENTRY %d\n", proc->pid);
     sysfs_del_ent(proc->fs_entry);
-    kdebug("END DEL ENTRY %d\n", proc->pid);
 }
 
 void context_save_fpu(struct thread *new, struct thread *old) {
@@ -754,6 +750,10 @@ __attribute__((noreturn)) void sys_exit(int status) {
     panic("This code shouldn't run\n");
 }
 
+void sys_yield(void) {
+    yield();
+}
+
 void sys_sigreturn(void) {
     context_sigreturn();
 }