diff options
| -rw-r--r-- | kernel/kernelvec.S | 2 | ||||
| -rw-r--r-- | kernel/pipe.c | 82 | ||||
| -rw-r--r-- | kernel/proc.c | 40 |
3 files changed, 57 insertions, 67 deletions
diff --git a/kernel/kernelvec.S b/kernel/kernelvec.S index e9b0ced..0efde8b 100644 --- a/kernel/kernelvec.S +++ b/kernel/kernelvec.S @@ -90,7 +90,6 @@ machinevec: sd a1, 0(a0) sd a2, 8(a0) sd a3, 16(a0) - sd a4, 24(a0) # add another second to mtimecmp0. ld a1, 32(a0) # CLINT_MTIMECMP(hart) @@ -103,7 +102,6 @@ machinevec: li a1, 2 csrw sip, a1 - ld a4, 24(a0) ld a3, 16(a0) ld a2, 8(a0) ld a1, 0(a0) diff --git a/kernel/pipe.c b/kernel/pipe.c index eca5959..2fcb2ee 100644 --- a/kernel/pipe.c +++ b/kernel/pipe.c @@ -22,33 +22,33 @@ struct pipe { int pipealloc(struct file **f0, struct file **f1) { - struct pipe *p; + struct pipe *pi; - p = 0; + pi = 0; *f0 = *f1 = 0; if((*f0 = filealloc()) == 0 || (*f1 = filealloc()) == 0) goto bad; - if((p = (struct pipe*)kalloc()) == 0) + if((pi = (struct pipe*)kalloc()) == 0) goto bad; - p->readopen = 1; - p->writeopen = 1; - p->nwrite = 0; - p->nread = 0; - initlock(&p->lock, "pipe"); + pi->readopen = 1; + pi->writeopen = 1; + pi->nwrite = 0; + pi->nread = 0; + initlock(&pi->lock, "pipe"); (*f0)->type = FD_PIPE; (*f0)->readable = 1; (*f0)->writable = 0; - (*f0)->pipe = p; + (*f0)->pipe = pi; (*f1)->type = FD_PIPE; (*f1)->readable = 0; (*f1)->writable = 1; - (*f1)->pipe = p; + (*f1)->pipe = pi; return 0; //PAGEBREAK: 20 bad: - if(p) - kfree((char*)p); + if(pi) + kfree((char*)pi); if(*f0) fileclose(*f0); if(*f1) @@ -57,73 +57,73 @@ pipealloc(struct file **f0, struct file **f1) } void -pipeclose(struct pipe *p, int writable) +pipeclose(struct pipe *pi, int writable) { - acquire(&p->lock); + acquire(&pi->lock); if(writable){ - p->writeopen = 0; - wakeup(&p->nread); + pi->writeopen = 0; + wakeup(&pi->nread); } else { - p->readopen = 0; - wakeup(&p->nwrite); + pi->readopen = 0; + wakeup(&pi->nwrite); } - if(p->readopen == 0 && p->writeopen == 0){ - release(&p->lock); - kfree((char*)p); + if(pi->readopen == 0 && pi->writeopen == 0){ + release(&pi->lock); + kfree((char*)pi); } else - release(&p->lock); + release(&pi->lock); } //PAGEBREAK: 40 int -pipewrite(struct pipe *p, uint64 addr, int n) +pipewrite(struct pipe *pi, uint64 addr, int n) { int i; char ch; struct proc *pr = myproc(); - acquire(&p->lock); + acquire(&pi->lock); for(i = 0; i < n; i++){ - while(p->nwrite == p->nread + PIPESIZE){ //DOC: pipewrite-full - if(p->readopen == 0 || myproc()->killed){ - release(&p->lock); + while(pi->nwrite == pi->nread + PIPESIZE){ //DOC: pipewrite-full + if(pi->readopen == 0 || myproc()->killed){ + release(&pi->lock); return -1; } - wakeup(&p->nread); - sleep(&p->nwrite, &p->lock); //DOC: pipewrite-sleep + wakeup(&pi->nread); + sleep(&pi->nwrite, &pi->lock); //DOC: pipewrite-sleep } if(copyin(pr->pagetable, &ch, addr + i, 1) == -1) break; - p->data[p->nwrite++ % PIPESIZE] = ch; + pi->data[pi->nwrite++ % PIPESIZE] = ch; } - wakeup(&p->nread); //DOC: pipewrite-wakeup1 - release(&p->lock); + wakeup(&pi->nread); //DOC: pipewrite-wakeup1 + release(&pi->lock); return n; } int -piperead(struct pipe *p, uint64 addr, int n) +piperead(struct pipe *pi, uint64 addr, int n) { int i; struct proc *pr = myproc(); char ch; - acquire(&p->lock); - while(p->nread == p->nwrite && p->writeopen){ //DOC: pipe-empty + acquire(&pi->lock); + while(pi->nread == pi->nwrite && pi->writeopen){ //DOC: pipe-empty if(myproc()->killed){ - release(&p->lock); + release(&pi->lock); return -1; } - sleep(&p->nread, &p->lock); //DOC: piperead-sleep + sleep(&pi->nread, &pi->lock); //DOC: piperead-sleep } for(i = 0; i < n; i++){ //DOC: piperead-copy - if(p->nread == p->nwrite) + if(pi->nread == pi->nwrite) break; - ch = p->data[p->nread++ % PIPESIZE]; + ch = pi->data[pi->nread++ % PIPESIZE]; if(copyout(pr->pagetable, addr + i, &ch, 1) == -1) break; } - wakeup(&p->nwrite); //DOC: piperead-wakeup - release(&p->lock); + wakeup(&pi->nwrite); //DOC: piperead-wakeup + release(&pi->lock); return i; } diff --git a/kernel/proc.c b/kernel/proc.c index 087d504..b9babed 100644 --- a/kernel/proc.c +++ b/kernel/proc.c @@ -55,7 +55,7 @@ mycpu(void) { return c; } -// Return the current struct proc *. +// Return the current struct proc *, or zero if none. struct proc* myproc(void) { push_off(); @@ -314,13 +314,12 @@ void exit(void) { struct proc *p = myproc(); - int fd; if(p == initproc) panic("init exiting"); // Close all open files. - for(fd = 0; fd < NOFILE; fd++){ + for(int fd = 0; fd < NOFILE; fd++){ if(p->ofile[fd]){ struct file *f = p->ofile[fd]; fileclose(f); @@ -337,14 +336,14 @@ exit(void) acquire(&p->lock); - // Give our children to init. + // Give any children to init. reparent(p, p->parent); - p->state = ZOMBIE; - // Parent might be sleeping in wait(). wakeup1(p->parent); + p->state = ZOMBIE; + release(&p->parent->lock); // Jump into the scheduler, never to return. @@ -416,7 +415,7 @@ scheduler(void) c->proc = 0; for(;;){ - // Give devices a brief chance to interrupt. + // Avoid deadlock by ensuring that devices can interrupt. intr_on(); for(p = proc; p < &proc[NPROC]; p++) { @@ -505,12 +504,6 @@ sleep(void *chan, struct spinlock *lk) { struct proc *p = myproc(); - if(p == 0) - panic("sleep"); - - if(lk == 0) - panic("sleep without lk"); - // Must acquire p->lock in order to // change p->state and then call sched. // Once we hold p->lock, we can be @@ -538,17 +531,6 @@ sleep(void *chan, struct spinlock *lk) } } -//PAGEBREAK! -// Wake up p if it is sleeping in wait(); used by exit(). -// Caller must hold p->lock. -static void -wakeup1(struct proc *p) -{ - if(p->chan == p && p->state == SLEEPING) { - p->state = RUNNABLE; - } -} - // Wake up all processes sleeping on chan. // Must be called without any p->lock. void @@ -565,6 +547,16 @@ wakeup(void *chan) } } +// Wake up p if it is sleeping in wait(); used by exit(). +// Caller must hold p->lock. +static void +wakeup1(struct proc *p) +{ + if(p->chan == p && p->state == SLEEPING) { + p->state = RUNNABLE; + } +} + // Kill the process with the given pid. // The victim won't exit until it tries to return // to user space (see usertrap() in trap.c). |