/*
* New threads actually come through here on the way to the function
* they're supposed to start in. This is so when that function exits,
* thread_exit() can be called automatically.
*/
void
mi_threadstart(void *data1, unsigned long data2,
void (*func)(void *, unsigned long))
{
/* If we have an address space, activate it */
if (curthread->t_vmspace) {
as_activate(curthread->t_vmspace);
}
/* Enable interrupts */
spl0();
assert(curthread->pid >= 1);
//kprintf("curthread pid is %d\n",curthread->pid);
#if OPT_SYNCHPROBS
/* Yield a random number of times to get a good mix of threads */
{
int i, n;
n = random()%161 + random()%161;
for (i=0; i<n; i++) {
thread_yield();
}
}
#endif
#if OPT_A2
int result = conSetup(curthread); // stdin , stdout, stderr
if(result) panic("Out of Memory\n");
#endif
/* Call the function */
func(data1, data2);
/* Done. */
thread_exit();
}
void
md_forkentry(void * data1, unsigned long unused) {
//(void)unused;
struct fork_info * info = data1;
struct addrspace * new_as;
struct trapframe new_tf;
/* copy address space */
if (as_copy(info->parent->t_vmspace, &new_as)) {
info->child_pid = ENOMEM; // Means no memory for process
V(info->sem); // child is done, parent should resume.
thread_exit();
}
curthread->t_vmspace = new_as;
as_activate(new_as);
/* copy trap frame */
memcpy(&new_tf, info->tf, sizeof(struct trapframe));
/* change tf's registers to return values for syscall */
new_tf.tf_v0 = 0;
new_tf.tf_a3 = 0;
new_tf.tf_epc += 4;
/* create process and get the pid */
struct thread *new_process = kmalloc(sizeof(struct thread));
new_process->parent_pid = curthread->t_pid;
proc_table++;
new_process->t_pid = create_tpid();
proc_table++;
V(info->sem);
mips_usermode(&new_tf);
/* mips_usermode does not return */
}
int sys_fork(struct trapframe *tf)
{
struct thread* newthread;
struct trapframe* newtf;
struct addrspace* newas;
int result;
newtf = (struct trapframe*) kmalloc(sizeof(struct trapframe));
if (newtf == NULL){
return ENOMEM;
}
*newtf = *tf;
int err;
err= as_copy(curthread->t_vmspace,&newas);
if (err){
return ENOMEM;
}
as_activate(curthread->t_vmspace);
result = thread_fork(curthread->t_name, newtf,(unsigned long)newas,
(void (*)(void *, unsigned long)) md_forkentry,&newthread);
if (result)
return -ENOMEM;
return newthread->t_pid;
}
void forked_child_thread_entry(void * ptr, unsigned long val) {
(void)val;
as_activate();
KASSERT(ptr != NULL);
struct trapframe * tf = ptr;
enter_forked_process(tf);
}
/* This is the entry point of the forked child process */
int
md_forkentry(void* tf, unsigned long vmspace)
{
// int spl = splhigh();
//kprintf(" process %d is in enter md_forkentry\n",curthread->pID);
struct trapframe child_tf;
struct trapframe *tf_parent = (struct trapframe*) tf;
assert(tf_parent != NULL);
// memcpy(child_tf, tf, sizeof(struct trapframe));
tf_parent->tf_epc += 4;
//we set the return value to be 0.
tf_parent->tf_v0 = 0;
tf_parent->tf_a3 = 0;
// Load Address Space of Child and Activate it.
curthread->t_vmspace = (struct addrspace*)vmspace;
assert(curthread->t_vmspace != NULL);
as_activate(curthread->t_vmspace);
child_tf = *tf_parent;
mips_usermode(&child_tf);
// we should never reach here
panic("switching to user mode returned\n");
return 0;
}
void md_forkentry(struct trapframe *tf,unsigned long addrspace_copy)
{
/*
* This function is provided as a reminder. You need to write
* both it and the code that calls it.
*
* Thus, you can trash it and do things another way if you prefer.
*/
//(void)tf;
//kprintf("\n md_forkentry");
tf->tf_v0=0;
tf->tf_a3=0;
curthread->t_vmspace=(struct addrspace*)addrspace_copy;
if(curthread->t_vmspace!=NULL){
as_activate(curthread->t_vmspace);
}
//copy modified trap frame from kernel heap to stack
struct trapframe tf_temp=*tf;//=kmalloc(sizeof(struct trapframe));
tf_temp.tf_v0=tf->tf_v0;
tf_temp.tf_a0=tf->tf_a0;
tf_temp.tf_a1=tf->tf_a1;
tf_temp.tf_a2=tf->tf_a2;
tf_temp.tf_a3=tf->tf_a3;
tf->tf_epc+=4;
mips_usermode(&tf_temp);
}
/*
* This function is where new threads start running. The arguments
* ENTRYPOINT, DATA1, and DATA2 are passed through from thread_fork.
*
* Because new code comes here from inside the middle of
* thread_switch, the beginning part of this function must match the
* tail of thread_switch.
*/
void
thread_startup(void (*entrypoint)(void *data1, unsigned long data2),
void *data1, unsigned long data2)
{
struct thread *cur;
cur = curthread;
/* Clear the wait channel and set the thread state. */
cur->t_wchan_name = NULL;
cur->t_state = S_RUN;
/* Release the runqueue lock acquired in thread_switch. */
spinlock_release(&curcpu->c_runqueue_lock);
/* Activate our address space in the MMU. */
as_activate();
/* Clean up dead threads. */
exorcise();
/* Enable interrupts. */
spl0();
/* Call the function. */
entrypoint(data1, data2);
/* Done. */
thread_exit();
}
void
enter_process(void *tf,unsigned long addr)
{
struct trapframe *childframe,child_tf;
struct addrspace *childspace;
if(tf!=NULL)
{
tf = (struct trapframe *) tf;
childframe = tf;
//copy the trapframe info now into the child_tf
// child_tf = *childframe;
memcpy(&child_tf,tf,sizeof(struct trapframe));
child_tf.tf_a3=0;
child_tf.tf_v0=0;
child_tf.tf_epc +=4;
pid_t parentid = (pid_t)addr;
if(process_array[curthread->t_pid]->parent_id!=parentid)
process_array[curthread->t_pid]->parent_id=parentid;
if(!(curthread->t_addrspace==NULL))
{
childspace = curthread->t_addrspace;
as_activate(childspace);
}
mips_usermode(&child_tf);
}
}
void
md_forkentry(struct trapframe *tf, unsigned int vmspace)
{
struct trapframe child_kstack;
/* copy trapframe of parent to chile procss*/
memcpy(&child_kstack, tf, sizeof(struct trapframe));
/* release trapframe when allocated at function process*/
kfree(tf);
/* activate addrspace*/
as_activate((struct addrspace *)vmspace);
/* increment pc*/
child_kstack.tf_epc += 4;
child_kstack.tf_v0 = 0;
child_kstack.tf_a3 = 0;
/* release lock so that other process can execute process_fork*/
// lock_release(forklock);
/* execute chile process*/
mips_usermode(&child_kstack);
}
void
md_forkentry(struct trapframe *tf, unsigned long child_addr)
{
/*
this function is basically for the child thread, remember the threadfor in sys_fork, it calls the md_forkentry and passed in new TF and addressspace and the child_thread.
*/
//kprintf("just enter forkentry\n");
struct trapframe* modifiy_tf;
struct trapframe dumbvalue;
struct addrspace* new_addr = (struct addrspace*) child_addr;
modifiy_tf= kmalloc(sizeof(struct trapframe));
//kprintf("just enter memcpy modified tf and tf\n");
memcpy(modifiy_tf, tf, sizeof(struct trapframe));
//kprintf("just after memcpy modified tf and tf\n");
//*modifiy_tf = *tf;
modifiy_tf->tf_v0 = 0;
modifiy_tf->tf_a3 = 0;
modifiy_tf->tf_epc +=4;
curthread->t_vmspace = new_addr;
//activie the addressspace
//kprintf("activate thread -- pid: %d\n", curthread->t_pid);
as_activate(curthread->t_vmspace);
//memcpy(dumbvalue, tf, sizeof(struct trapframe));
//kprintf("just enter dumbvalue =*tf\n");
dumbvalue = *modifiy_tf;
//kprintf("just leave dumbvalue =*tf\n");
mips_usermode(&dumbvalue);
}
/*
* New threads actually come through here on the way to the function
* they're supposed to start in. This is so when that function exits,
* thread_exit() can be called automatically.
*/
void
mi_threadstart(void *data1, unsigned long data2,
void (*func)(void *, unsigned long))
{
/* If we have an address space, activate it */
if (curthread->t_vmspace) {
as_activate(curthread->t_vmspace);
}
/* Enable interrupts */
spl0();
#if OPT_SYNCHPROBS
/* Yield a random number of times to get a good mix of threads */
{
int i, n;
n = random()%161 + random()%161;
for (i=0; i<n; i++) {
thread_yield();
}
}
#endif
/* Call the function */
func(data1, data2);
/* Done. */
thread_exit(0);
}
int
runprogram(char *progname)
{
struct addrspace *as;
struct vnode *v;
vaddr_t entrypoint, stackptr;
int result;
/* Open the file. */
result = vfs_open(progname, O_RDONLY, 0, &v);
if (result) {
return result;
}
/* We should be a new process. */
KASSERT(curproc_getas() == NULL);
/* Create a new address space. */
#if OPT_A3
as = as_create(progname);
#else
as = as_create();
#endif
if (as ==NULL) {
vfs_close(v);
return ENOMEM;
}
/* Switch to it and activate it. */
curproc_setas(as);
as_activate();
/* Load the executable. */
result = load_elf(v, &entrypoint);
if (result) {
/* p_addrspace will go away when curproc is destroyed */
vfs_close(v);
return result;
}
/* Done with the file now. */
vfs_close(v);
/* Define the user stack in the address space */
result = as_define_stack(as, &stackptr);
if (result) {
/* p_addrspace will go away when curproc is destroyed */
return result;
}
/* Warp to user mode. */
enter_new_process(0 /*argc*/, NULL /*userspace addr of argv*/,
stackptr, entrypoint);
/* enter_new_process does not return. */
panic("enter_new_process returned\n");
return EINVAL;
}
/*
* Load program "progname" and start running it in usermode.
* Does not return except on error.
*
* Calls vfs_open on progname and thus may destroy it.
*/
int
runprogram(char *progname)
{
struct vnode *v;
vaddr_t entrypoint, stackptr;
int result;
/* Open the file. */
result = vfs_open(progname, O_RDONLY, 0, &v);
if (result) {
return result;
}
/* We should be a new thread. */
KASSERT(curthread->t_addrspace == NULL);
/* Create a new address space. */
curthread->t_addrspace = as_create();
if (curthread->t_addrspace==NULL) {
vfs_close(v);
return ENOMEM;
}
curthread->t_filetable = filetable_create();
if(curthread->t_filetable == NULL){
return ENOMEM;
}
/* Activate it. */
as_activate(curthread->t_addrspace);
/* Load the executable. */
result = load_elf(v, &entrypoint);
if (result) {
/* thread_exit destroys curthread->t_addrspace */
vfs_close(v);
return result;
}
/* Done with the file now. */
vfs_close(v);
/* Define the user stack in the address space */
result = as_define_stack(curthread->t_addrspace, &stackptr);
if (result) {
/* thread_exit destroys curthread->t_addrspace */
return result;
}
/* Warp to user mode. */
enter_new_process(0 /*argc*/, NULL /*userspace addr of argv*/,
stackptr, entrypoint);
/* enter_new_process does not return. */
panic("enter_new_process returned\n");
return EINVAL;
}
/*
* Load program "progname" and start running it in usermode.
* Does not return except on error.
*
* Calls vfs_open on progname and thus may destroy it.
*/
int
runprogram(char *progname)
{
struct vnode *v;
vaddr_t entrypoint, stackptr;
int result;
/* Open the file. */
result = vfs_open(progname, O_RDONLY, &v);
if (result) {
return result;
}
/* We should be a new thread. */
assert(curthread->t_vmspace == NULL);
/* Create a new address space. */
curthread->t_vmspace = as_create();
if (curthread->t_vmspace==NULL) {
vfs_close(v);
return ENOMEM;
}
//kprintf("\n in runprogram");
assignPid();
/* Activate it. */
as_activate(curthread->t_vmspace);
/* Load the executable. */
result = load_elf(v, &entrypoint);
if (result) {
/* thread_exit destroys curthread->t_vmspace */
vfs_close(v);
return result;
}
/* Done with the file now. */
vfs_close(v);
/* Define the user stack in the address space */
result = as_define_stack(curthread->t_vmspace, &stackptr);
if (result) {
/* thread_exit destroys curthread->t_vmspace */
return result;
}
/* Warp to user mode. */
md_usermode(0 /*argc*/, NULL /*userspace addr of argv*/,
stackptr, entrypoint);
/* md_usermode does not return */
panic("md_usermode returned\n");
return EINVAL;
}
/*
* Enter user mode for a newly forked process.
*
* This function is provided as a reminder. You need to write
* both it and the code that calls it.
*
* Thus, you can trash it and do things another way if you prefer.
*/
void
enter_forked_process(struct trapframe *tf)
{
//kprintf("enter_forked_process \n");
#if OPT_A2
struct trapframe thisTF = *tf; //create tf on stack
thisTF.tf_v0 =0; //child returns with 0
thisTF.tf_a3 =0; //error coding
thisTF.tf_epc +=4; //counter
as_activate();
mips_usermode(&thisTF);
panic("Should not return from mips usermode\n");
#else
(void)tf;
#endif
}
void child_process_entry(void *data1, unsigned long data2)
{
struct trapframe *tf = (struct trapframe *)data1 ;
curthread->t_addrspace = (struct addrspace *)data2 ;
as_activate(curthread->t_addrspace) ;
struct trapframe usertf ;
usertf = *tf;
//memcpy(&usertf,tf ,sizeof(struct trapframe ));
usertf.tf_v0 = 0 ;
usertf.tf_a3 = 0 ;
usertf.tf_epc += 4 ;
kfree(tf) ;
mips_usermode(&usertf) ;
}
void child_fork_entry(void *data1, unsigned long data2)
{
struct trapframe *ctf = (struct trapframe *)data1;
struct addrspace *caddr = (struct addrspace *)data2;
ctf->tf_a3= 0;
ctf->tf_v0= 0;
ctf->tf_epc = ctf->tf_epc+4;
curthread->t_addrspace = caddr;
as_activate(curthread->t_addrspace);
struct trapframe tf;
memcpy(&tf,ctf,sizeof(struct trapframe));
mips_usermode(&tf);
//KASSERT(SAME_STACK(cpustacks[curcpu->c_number]-1, (vaddr_t)tf_copy));
}
/*
* Enter user mode for a newly forked process.
*
* This function is provided as a reminder. You need to write
* both it and the code that calls it.
*
* Thus, you can trash it and do things another way if you prefer.
*/
void
enter_forked_process(struct trapframe *tf)
{
#if OPT_A2
struct trapframe forkTf = *tf;
forkTf.tf_a3 = 0; //signal no error
forkTf.tf_v0 = 0;
forkTf.tf_epc += 4; //advance the PC, to avoid the syscall again
as_activate();
mips_usermode(&forkTf);
panic("can't come here");
#else
(void)tf;
#endif //OPT_A2
}
/*
* Enter user mode for a newly forked process.
*
* This function is provided as a reminder. You need to write
* both it and the code that calls it.
*
* Thus, you can trash it and do things another way if you prefer.
*/
void
enter_forked_process(void* ptr, unsigned long args)
{
//panic("test");
//while(1) {}
struct trapframe childtf;
bzero(&childtf, sizeof(childtf));
childtf = *(struct trapframe *) ptr;
childtf.tf_v0 = 0;
childtf.tf_a3 = 0;
childtf.tf_epc += 4;
kfree(ptr);
// load and activate the address space
struct addrspace* as = (struct addrspace *) args;
proc_setas(as);
as_activate();
mips_usermode(&childtf);
}
void
enter_forked_process(void *data1, unsigned long data2){
struct trapframe *childtf = ((void **)data1)[0];
struct addrspace *childas = ((void **)data1)[1];
// using local variable to put tf on stack
struct trapframe local = *childtf;
// switch to childas
curproc_setas(childas);
as_activate();
// set register
local.tf_epc += 4;
local.tf_v0 = 0;
local.tf_a3 = 0;
(void)data2;
mips_usermode(&local);
}
void
child_forkentry(void *data1, unsigned long data2){
struct trapframe st_trapframe;
struct trapframe* childtf = (struct trapframe*) data1;
struct addrspace* childaddr = (struct addrspace*) data2;
childtf->tf_v0 = 0;
childtf->tf_a3 = 0;
childtf->tf_epc += 4;
memcpy(&st_trapframe, childtf, sizeof(struct trapframe));
kfree(childtf);
childtf = NULL;
curproc->p_addrspace = childaddr;
as_activate();
mips_usermode(&st_trapframe);
};
void
md_forkentry(struct fork_data *fd, unsigned long un)
{
(void) un;
struct trapframe local_tf;
local_tf = *(fd->tf);
curthread->t_vmspace = fd->addr;
as_activate(curthread->t_vmspace);
kfree(fd->tf);
kfree(fd);
local_tf.tf_epc += 4;
local_tf.tf_a3 = 0;
local_tf.tf_v0 = 0;
mips_usermode(&local_tf);
}
/*
* This function is where new threads start running. The arguments
* ENTRYPOINT, DATA1, and DATA2 are passed through from thread_fork.
*
* Because new code comes here from inside the middle of
* thread_switch, the beginning part of this function must match the
* tail of thread_switch.
*/
void
thread_startup(void (*entrypoint)(void *data1, unsigned long data2),
void *data1, unsigned long data2)
{
struct thread *cur;
cur = curthread;
/* Clear the wait channel and set the thread state. */
cur->t_wchan_name = NULL;
cur->t_state = S_RUN;
/* Release the runqueue lock acquired in thread_switch. */
spinlock_release(&curcpu->c_runqueue_lock);
/* Activate our address space in the MMU. */
as_activate();
/* Clean up dead threads. */
exorcise();
/* Enable interrupts. */
spl0();
#if OPT_SYNCHPROBS
/* Yield a random number of times to get a good mix of threads. */
{
int i, n;
n = random()%161 + random()%161;
for (i=0; i<n; i++) {
thread_yield();
}
}
#endif
/* Call the function. */
entrypoint(data1, data2);
/* Done. */
thread_exit();
}
/*
* Enter user mode for a newly forked process.
*
* This function is provided as a reminder. You need to write
* both it and the code that calls it.
*
* Thus, you can trash it and do things another way if you prefer.
*/
void
enter_forked_process(void *tf, unsigned long arg)
{
#if OPT_A2
(void) arg;
as_activate(); //activate the address space
struct trapframe stacktf;
stacktf = *(struct trapframe *) tf; //copy the trapframe
stacktf.tf_v0 = 0;
stacktf.tf_a3 = 0;
stacktf.tf_epc = stacktf.tf_epc + 4;
kfree(tf);
mips_usermode(&stacktf);
return;
#else
(void)tf;
(void)arg;
#endif
}
void
md_forkentry(struct trapframe *tf,unsigned long as_data)
{
struct trapframe tf_local;
struct trapframe *newtf;
struct addrspace *newas = (struct addrspace*) as_data;
tf_local = *tf;
newtf = &tf_local;
newtf->tf_v0 = 0;
newtf->tf_a3 = 0;
newtf->tf_epc += 4;
kfree(tf);
curthread->t_vmspace = newas;
as_activate(curthread->t_vmspace);
mips_usermode(&tf_local);
}
void
md_forkentry(struct trapframe *tf)
{
/*
* This function is used to copy the trap frame of the parent process into
* the the child's and return the child process to user mode
*/
//int spl;
// disable interrupts
//spl = splhigh();
//new trap frame for the child
struct trapframe newtf;
// copy the trap frame
memcpy (&newtf, tf, sizeof(struct trapframe));
//newtf = *tf;
newtf.tf_v0 = 0; // return value of the child process should be 0
newtf.tf_epc += 4; // advance the PC to avoid redo of the syscall
newtf.tf_a3 = 0; // indicate that there are no errors
curthread->t_vmspace = (struct addrspace*)tf->tf_a0;
//memcpy (curthread->t_vmspace, (struct addrspace*) tf->tf_a0, sizeof(struct addrspace*));
//kprintf ("BEOFRE");
//struct addrspace *temp = (struct addrspace*) tf->tf_a0;
//int test = as_copy(curthread->t_vmspace, &temp);
//kprintf ("as_copy: %d\n", test);
//kprintf ("TESTING HERE");
as_activate(curthread->t_vmspace);
kfree (tf);
V(curthread->t_sem_fork);
//kprintf ("md_forkentry childpid: %d\n", curthread->t_pid);
// re-enable interrupts
//splx(spl);
// Warp to user mode
mips_usermode(&newtf);
}
static
void md_forkentry(struct trapframe *tf, unsigned long vmspace)
{
// disable interrupt
struct addrspace *t_vmspace = (struct addrspace*)vmspace;
splhigh();
if (t_vmspace == NULL) {
thread_exit();
}
assert(curthread->t_vmspace == NULL);
curthread->t_vmspace = t_vmspace;
// copy the trapframe to our own stack and free it
struct trapframe mytf;
memmove(&mytf, tf, sizeof(mytf));
kfree(tf);
// set the return value to 0
mytf.tf_v0 = 0;
mytf.tf_a3 = 0;
// next instruction
mytf.tf_epc += 4;
/* Activate it. */
// as_hold(curthread->t_vmspace);
as_activate(curthread->t_vmspace);
// kprintf("sw to user mode.\n");
// switch to usermode
mips_usermode(&mytf);
// should not come here
assert(0);
}
void entrypoint(void* data1, unsigned long data2) {
struct trapframe *tf, tfnew;
struct addrspace * addr;
tf = (struct trapframe *) data1;
addr = (struct addrspace *) data2;
tf->tf_a3 = 0;
tf->tf_v0 = 0;
tf->tf_epc += 4;
//kprintf(" LMAO ");
curproc->p_addrspace = addr;
//kprintf(" rekt ");
//memcpy(tfnew, tf, sizeof(struct trapframe));
as_activate();
//kprintf(" nips ");
tfnew = *tf;
//kprintf(" nips ");
mips_usermode(&tfnew);
//kprintf(" SWAG ");
}
/*
* Load program "progname" and start running it in usermode.
* Does not return except on error.
*
* Calls vfs_open on progname and thus may destroy it.
*/
int runprogram(char *progname, char **args, unsigned long nargs) {
struct vnode *v;
vaddr_t entrypoint, stackptr;
int result;
/*Initialize Console*/
char *consolein;
char *consoleout;
char *consoleerr;
consolein = kstrdup("con:");
consoleout = kstrdup("con:");
consoleerr = kstrdup("con:");
curthread->t_fdtable[0] = (struct fdesc*) kmalloc(sizeof(struct fdesc));
if (vfs_open(consolein, O_RDONLY, 0664, &(curthread->t_fdtable[0]->vn))) {
return EINVAL;
}
curthread->t_fdtable[0]->name = consolein;
curthread->t_fdtable[0]->flag = O_RDONLY;
curthread->t_fdtable[0]->ref_count = 1;
curthread->t_fdtable[0]->filelock = lock_create("STDIN");
kfree(consolein);
curthread->t_fdtable[1] = (struct fdesc*) kmalloc(sizeof(struct fdesc));
if (vfs_open(consoleout, O_WRONLY, 0664, &(curthread->t_fdtable[1]->vn))) {
return EINVAL;
}
curthread->t_fdtable[1]->name = consoleout;
curthread->t_fdtable[1]->flag = O_WRONLY;
curthread->t_fdtable[1]->ref_count = 1;
curthread->t_fdtable[1]->filelock = lock_create("STDOUT");
kfree(consoleout);
curthread->t_fdtable[2] = (struct fdesc*) kmalloc(sizeof(struct fdesc));
if (vfs_open(consoleerr, O_WRONLY, 0664, &(curthread->t_fdtable[2]->vn))) {
return EINVAL;
}
curthread->t_fdtable[2]->name = consoleerr;
curthread->t_fdtable[2]->flag = O_WRONLY;
curthread->t_fdtable[2]->ref_count = 1;
curthread->t_fdtable[2]->filelock = lock_create("STDERR");
kfree(consoleerr);
/*Console Initialized*/
/* Open the file. */
result = vfs_open(progname, O_RDONLY, 0, &v);
if (result) {
return result;
}
/* We should be a new thread. */
KASSERT(curthread->t_addrspace == NULL);
/* Create a new address space. */
curthread->t_addrspace = as_create();
if (curthread->t_addrspace == NULL ) {
vfs_close(v);
return ENOMEM;
}
/* Activate it. */
as_activate(curthread->t_addrspace);
/* Load the executable. */
result = load_elf(v, &entrypoint);
if (result) {
/* thread_exit destroys curthread->t_addrspace */
vfs_close(v);
return result;
}
/* Done with the file now. */
vfs_close(v);
/* Define the user stack in the address space */
result = as_define_stack(curthread->t_addrspace, &stackptr);
if (result) {
/* thread_exit destroys curthread->t_addrspace */
return result;
}
int argc = (signed) nargs;
int err;
char** argv;
//kmalloc argv with size of char* times nargs+1
argv = kmalloc((nargs + 1) * sizeof(userptr_t));
size_t len;
for (int i = 0; i < argc; i++) {
len = strlen(args[i]) + 1;
len = (len + 4 - 1) & ~(size_t) (4 - 1);
stackptr -= len;
if ((err = copyout(args[i], (userptr_t) stackptr, len)) != 0) {
kprintf("error copyout");
}
argv[i] = (char*) stackptr;
}
argv[nargs] = NULL;
stackptr -= (nargs + 1) * sizeof(userptr_t);
if ((err = copyout(argv, (userptr_t) stackptr, (nargs + 1) * sizeof(char*)))) {
kprintf("error copying");
}
/* Warp to user mode. */
enter_new_process(argc, (userptr_t) stackptr /*userspace addr of argv*/,
stackptr, entrypoint);
/* enter_new_process does not return. */
panic("enter_new_process returned\n");
return EINVAL;
}
/*
* High level, machine-independent context switch code.
*
* The current thread is queued appropriately and its state is changed
* to NEWSTATE; another thread to run is selected and switched to.
*
* If NEWSTATE is S_SLEEP, the thread is queued on the wait channel
* WC, protected by the spinlock LK. Otherwise WC and Lk should be
* NULL.
*/
static
void
thread_switch(threadstate_t newstate, struct wchan *wc, struct spinlock *lk)
{
struct thread *cur, *next;
int spl;
DEBUGASSERT(curcpu->c_curthread == curthread);
DEBUGASSERT(curthread->t_cpu == curcpu->c_self);
/* Explicitly disable interrupts on this processor */
spl = splhigh();
cur = curthread;
/*
* If we're idle, return without doing anything. This happens
* when the timer interrupt interrupts the idle loop.
*/
if (curcpu->c_isidle) {
splx(spl);
return;
}
/* Check the stack guard band. */
thread_checkstack(cur);
/* Lock the run queue. */
spinlock_acquire(&curcpu->c_runqueue_lock);
/* Micro-optimization: if nothing to do, just return */
if (newstate == S_READY && threadlist_isempty(&curcpu->c_runqueue)) {
spinlock_release(&curcpu->c_runqueue_lock);
splx(spl);
return;
}
/* Put the thread in the right place. */
switch (newstate) {
case S_RUN:
panic("Illegal S_RUN in thread_switch\n");
case S_READY:
thread_make_runnable(cur, true /*have lock*/);
break;
case S_SLEEP:
cur->t_wchan_name = wc->wc_name;
/*
* Add the thread to the list in the wait channel, and
* unlock same. To avoid a race with someone else
* calling wchan_wake*, we must keep the wchan's
* associated spinlock locked from the point the
* caller of wchan_sleep locked it until the thread is
* on the list.
*/
threadlist_addtail(&wc->wc_threads, cur);
spinlock_release(lk);
break;
case S_ZOMBIE:
cur->t_wchan_name = "ZOMBIE";
threadlist_addtail(&curcpu->c_zombies, cur);
break;
}
cur->t_state = newstate;
/*
* Get the next thread. While there isn't one, call md_idle().
* curcpu->c_isidle must be true when md_idle is
* called. Unlock the runqueue while idling too, to make sure
* things can be added to it.
*
* Note that we don't need to unlock the runqueue atomically
* with idling; becoming unidle requires receiving an
* interrupt (either a hardware interrupt or an interprocessor
* interrupt from another cpu posting a wakeup) and idling
* *is* atomic with respect to re-enabling interrupts.
*
* Note that c_isidle becomes true briefly even if we don't go
* idle. However, because one is supposed to hold the runqueue
* lock to look at it, this should not be visible or matter.
*/
/* The current cpu is now idle. */
curcpu->c_isidle = true;
do {
next = threadlist_remhead(&curcpu->c_runqueue);
if (next == NULL) {
spinlock_release(&curcpu->c_runqueue_lock);
cpu_idle();
spinlock_acquire(&curcpu->c_runqueue_lock);
}
} while (next == NULL);
curcpu->c_isidle = false;
/*
* Note that curcpu->c_curthread may be the same variable as
* curthread and it may not be, depending on how curthread and
* curcpu are defined by the MD code. We'll assign both and
* assume the compiler will optimize one away if they're the
* same.
*/
curcpu->c_curthread = next;
curthread = next;
/* do the switch (in assembler in switch.S) */
switchframe_switch(&cur->t_context, &next->t_context);
/*
* When we get to this point we are either running in the next
* thread, or have come back to the same thread again,
* depending on how you look at it. That is,
* switchframe_switch returns immediately in another thread
* context, which in general will be executing here with a
* different stack and different values in the local
* variables. (Although new threads go to thread_startup
* instead.) But, later on when the processor, or some
* processor, comes back to the previous thread, it's also
* executing here with the *same* value in the local
* variables.
*
* The upshot, however, is as follows:
*
* - The thread now currently running is "cur", not "next",
* because when we return from switchrame_switch on the
* same stack, we're back to the thread that
* switchframe_switch call switched away from, which is
* "cur".
*
* - "cur" is _not_ the thread that just *called*
* switchframe_switch.
*
* - If newstate is S_ZOMB we never get back here in that
* context at all.
*
* - If the thread just chosen to run ("next") was a new
* thread, we don't get to this code again until
* *another* context switch happens, because when new
* threads return from switchframe_switch they teleport
* to thread_startup.
*
* - At this point the thread whose stack we're now on may
* have been migrated to another cpu since it last ran.
*
* The above is inherently confusing and will probably take a
* while to get used to.
*
* However, the important part is that code placed here, after
* the call to switchframe_switch, does not necessarily run on
* every context switch. Thus any such code must be either
* skippable on some switches or also called from
* thread_startup.
*/
/* Clear the wait channel and set the thread state. */
cur->t_wchan_name = NULL;
cur->t_state = S_RUN;
/* Unlock the run queue. */
spinlock_release(&curcpu->c_runqueue_lock);
/* Activate our address space in the MMU. */
as_activate();
/* Clean up dead threads. */
exorcise();
/* Turn interrupts back on. */
splx(spl);
}
