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Commit 9be72339 authored by Chaumont Aymeric's avatar Chaumont Aymeric
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completed activity 7.2

parent 20f00294
Branches tp2-a-7-2
Tags tp2-act-7-2
No related merge requests found
......@@ -20,36 +20,45 @@ extern int devintr();
static const char *
scause_desc(uint64 stval);
void
trapinit(void)
void trapinit(void)
{
initlock(&tickslock, "time");
}
// set up to take exceptions and traps while in the kernel.
void
trapinithart(void)
void trapinithart(void)
{
w_stvec((uint64)kernelvec);
}
int handle_page_fault(struct proc* p, uint64 scause, uint64 stval, uint64 sepc){
int handle_page_fault(struct proc *p, uint64 scause, uint64 stval, uint64 sepc)
{
uint64 addr = PGROUNDDOWN(stval);
acquire(&p->vma_lock);
printf("handle_page_fault pid=%d (%s), scause=%p, stval=%p, sepc=%p\n", p->pid, p->name, scause, stval, sepc);
// proc_vmprint(p);
int flags = do_allocate(p->pagetable, p, addr, CAUSE_R);
release(&p->vma_lock);
if(flags < 0){
if(flags == ENOVMA){
if (flags < 0)
{
if (flags == ENOVMA)
{
printf("Could not find VMA associated with addr=%p\n", addr);
} else if (flags == ENOMEM){
}
else if (flags == ENOMEM)
{
printf("No more memory could be allocated from the kernel\n");
} else if (flags == ENOFILE){
}
else if (flags == ENOFILE)
{
printf("Could not read file associated with memory area\n");
} else if (flags == EMAPFAILED){
}
else if (flags == EMAPFAILED)
{
printf("mappages failed for an unknown reason\n");
} else if (flags == EBADPERM){
}
else if (flags == EBADPERM)
{
printf("Bad permission addr=%p, scause=%p\n", addr, scause);
}
......@@ -66,12 +75,11 @@ int handle_page_fault(struct proc* p, uint64 scause, uint64 stval, uint64 sepc){
// handle an interrupt, exception, or system call from user space.
// called from trampoline.S
//
void
usertrap(void)
void usertrap(void)
{
int which_dev = 0;
if((r_sstatus() & SSTATUS_SPP) != 0)
if ((r_sstatus() & SSTATUS_SPP) != 0)
panic("usertrap: not from user mode");
// send interrupts and exceptions to kerneltrap(),
......@@ -79,16 +87,17 @@ usertrap(void)
w_stvec((uint64)kernelvec);
struct proc *p = myproc();
// save user program counter.
p->tf->epc = r_sepc();
uint64 scause = r_scause();
if(scause == 8){
if (scause == 8)
{
// system call
if(p->killed)
if (p->killed)
exit(-1);
// sepc points to the ecall instruction,
......@@ -100,21 +109,27 @@ usertrap(void)
intr_on();
syscall();
} else if (scause == 0xf || scause == 0xd) {
}
else if (scause == 0xf || scause == 0xd || scause == 0xc)
{
handle_page_fault(p, scause, r_stval(), r_sepc());
} else if((which_dev = devintr()) != 0){
}
else if ((which_dev = devintr()) != 0)
{
// ok
} else {
}
else
{
printf("usertrap(): unexpected scause %p (%s) pid=%d\n", r_scause(), scause_desc(r_scause()), p->pid);
printf(" sepc=%p stval=%p\n", r_sepc(), r_stval());
p->killed = 1;
}
if(p->killed)
if (p->killed)
exit(-1);
// give up the CPU if this is a timer interrupt.
if(which_dev == 2)
if (which_dev == 2)
yield();
usertrapret();
......@@ -123,8 +138,7 @@ usertrap(void)
//
// return to user space
//
void
usertrapret(void)
void usertrapret(void)
{
struct proc *p = myproc();
......@@ -140,11 +154,11 @@ usertrapret(void)
p->tf->kernel_satp = r_satp(); // kernel page table
p->tf->kernel_sp = p->kstack + PGSIZE; // process's kernel stack
p->tf->kernel_trap = (uint64)usertrap;
p->tf->kernel_hartid = r_tp(); // hartid for cpuid()
p->tf->kernel_hartid = r_tp(); // hartid for cpuid()
// set up the registers that trampoline.S's sret will use
// to get to user space.
// set S Previous Privilege mode to User.
unsigned long x = r_sstatus();
x &= ~SSTATUS_SPP; // clear SPP to 0 for user mode
......@@ -157,36 +171,36 @@ usertrapret(void)
// tell trampoline.S the user page table to switch to.
uint64 satp = MAKE_SATP(p->pagetable);
// jump to trampoline.S at the top of memory, which
// jump to trampoline.S at the top of memory, which
// switches to the user page table, restores user registers,
// and switches to user mode with sret.
uint64 fn = TRAMPOLINE + (userret - trampoline);
((void (*)(uint64,uint64))fn)(TRAPFRAME, satp);
((void (*)(uint64, uint64))fn)(TRAPFRAME, satp);
}
// interrupts and exceptions from kernel code go here via kernelvec,
// on whatever the current kernel stack is.
void
kerneltrap()
void kerneltrap()
{
int which_dev = 0;
uint64 sepc = r_sepc();
uint64 sstatus = r_sstatus();
uint64 scause = r_scause();
if((sstatus & SSTATUS_SPP) == 0)
if ((sstatus & SSTATUS_SPP) == 0)
panic("kerneltrap: not from supervisor mode");
if(intr_get() != 0)
if (intr_get() != 0)
panic("kerneltrap: interrupts enabled");
if((which_dev = devintr()) == 0){
if ((which_dev = devintr()) == 0)
{
printf("scause %p (%s)\n", scause, scause_desc(scause));
printf("sepc=%p stval=%p\n", r_sepc(), r_stval());
panic("kerneltrap");
}
// give up the CPU if this is a timer interrupt.
if(which_dev == 2 && myproc() != 0 && myproc()->state == RUNNING)
if (which_dev == 2 && myproc() != 0 && myproc()->state == RUNNING)
yield();
// the yield() may have caused some traps to occur,
......@@ -195,12 +209,12 @@ kerneltrap()
w_sstatus(sstatus);
}
void
clockintr()
void clockintr()
{
acquire(&watchdog_lock);
acquire(&tickslock);
if (watchdog_time && ticks - watchdog_value > watchdog_time){
if (watchdog_time && ticks - watchdog_value > watchdog_time)
{
panic("watchdog !!!");
}
ticks++;
......@@ -214,45 +228,55 @@ clockintr()
// returns 2 if timer interrupt,
// 1 if other device,
// 0 if not recognized.
int
devintr()
int devintr()
{
uint64 scause = r_scause();
if((scause & 0x8000000000000000L) &&
(scause & 0xff) == 9){
if ((scause & 0x8000000000000000L) &&
(scause & 0xff) == 9)
{
// this is a supervisor external interrupt, via PLIC.
// irq indicates which device interrupted.
int irq = plic_claim();
if(irq == UART0_IRQ){
if (irq == UART0_IRQ)
{
uartintr();
} else if(irq == VIRTIO0_IRQ || irq == VIRTIO1_IRQ ){
}
else if (irq == VIRTIO0_IRQ || irq == VIRTIO1_IRQ)
{
virtio_disk_intr(irq - VIRTIO0_IRQ);
} else {
}
else
{
// the PLIC sends each device interrupt to every core,
// which generates a lot of interrupts with irq==0.
}
if(irq)
if (irq)
plic_complete(irq);
return 1;
} else if(scause == 0x8000000000000001L){
}
else if (scause == 0x8000000000000001L)
{
// software interrupt from a machine-mode timer interrupt,
// forwarded by timervec in kernelvec.S.
if(cpuid() == 0){
if (cpuid() == 0)
{
clockintr();
}
// acknowledge the software interrupt by clearing
// the SSIP bit in sip.
w_sip(r_sip() & ~2);
return 2;
} else {
}
else
{
return 0;
}
}
......@@ -261,61 +285,78 @@ static const char *
scause_desc(uint64 stval)
{
static const char *intr_desc[16] = {
[0] "user software interrupt",
[1] "supervisor software interrupt",
[2] "<reserved for future standard use>",
[3] "<reserved for future standard use>",
[4] "user timer interrupt",
[5] "supervisor timer interrupt",
[6] "<reserved for future standard use>",
[7] "<reserved for future standard use>",
[8] "user external interrupt",
[9] "supervisor external interrupt",
[10] "<reserved for future standard use>",
[11] "<reserved for future standard use>",
[12] "<reserved for future standard use>",
[13] "<reserved for future standard use>",
[14] "<reserved for future standard use>",
[15] "<reserved for future standard use>",
[0] "user software interrupt",
[1] "supervisor software interrupt",
[2] "<reserved for future standard use>",
[3] "<reserved for future standard use>",
[4] "user timer interrupt",
[5] "supervisor timer interrupt",
[6] "<reserved for future standard use>",
[7] "<reserved for future standard use>",
[8] "user external interrupt",
[9] "supervisor external interrupt",
[10] "<reserved for future standard use>",
[11] "<reserved for future standard use>",
[12] "<reserved for future standard use>",
[13] "<reserved for future standard use>",
[14] "<reserved for future standard use>",
[15] "<reserved for future standard use>",
};
static const char *nointr_desc[16] = {
[0] "instruction address misaligned",
[1] "instruction access fault",
[2] "illegal instruction",
[3] "breakpoint",
[4] "load address misaligned",
[5] "load access fault",
[6] "store/AMO address misaligned",
[7] "store/AMO access fault",
[8] "environment call from U-mode",
[9] "environment call from S-mode",
[10] "<reserved for future standard use>",
[11] "<reserved for future standard use>",
[12] "instruction page fault",
[13] "load page fault",
[14] "<reserved for future standard use>",
[15] "store/AMO page fault",
[0] "instruction address misaligned",
[1] "instruction access fault",
[2] "illegal instruction",
[3] "breakpoint",
[4] "load address misaligned",
[5] "load access fault",
[6] "store/AMO address misaligned",
[7] "store/AMO access fault",
[8] "environment call from U-mode",
[9] "environment call from S-mode",
[10] "<reserved for future standard use>",
[11] "<reserved for future standard use>",
[12] "instruction page fault",
[13] "load page fault",
[14] "<reserved for future standard use>",
[15] "store/AMO page fault",
};
uint64 interrupt = stval & 0x8000000000000000L;
uint64 code = stval & ~0x8000000000000000L;
if (interrupt) {
if (code < NELEM(intr_desc)) {
if (interrupt)
{
if (code < NELEM(intr_desc))
{
return intr_desc[code];
} else {
}
else
{
return "<reserved for platform use>";
}
} else {
if (code < NELEM(nointr_desc)) {
}
else
{
if (code < NELEM(nointr_desc))
{
return nointr_desc[code];
} else if (code <= 23) {
}
else if (code <= 23)
{
return "<reserved for future standard use>";
} else if (code <= 31) {
}
else if (code <= 31)
{
return "<reserved for custom use>";
} else if (code <= 47) {
}
else if (code <= 47)
{
return "<reserved for future standard use>";
} else if (code <= 63) {
}
else if (code <= 63)
{
return "<reserved for custom use>";
} else {
}
else
{
return "<reserved for future standard use>";
}
}
......
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