diff options
| -rw-r--r-- | kernel.ld | 7 | ||||
| -rw-r--r-- | proc.c | 16 | ||||
| -rw-r--r-- | trapasm.S | 11 |
3 files changed, 22 insertions, 12 deletions
@@ -41,9 +41,10 @@ SECTIONS .data : { *(.data) } - PROVIDE(edata = .); - .bss : { + bss : { + PROVIDE(edata = .); *(.bss) + *(COMMON) + PROVIDE(end = .); } - PROVIDE(end = .); } @@ -6,7 +6,6 @@ #include "x86.h" #include "proc.h" #include "spinlock.h" -#include "msr.h" struct { struct spinlock lock; @@ -17,7 +16,11 @@ static struct proc *initproc; int nextpid = 1; extern void forkret(void); + +// we can return two ways out of the kernel and +// for new processes we can choose either way extern void sysexit(void); +extern void trapret(void); static void wakeup1(void *chan); @@ -101,6 +104,10 @@ found: // Leave room for trap frame. sp -= sizeof *p->tf; + + if ((uint64) sp % 16) + panic("misaligned sp"); + p->tf = (struct trapframe*)sp; // Set up new context to start executing at forkret, @@ -132,6 +139,8 @@ userinit(void) inituvm(p->pgdir, _binary_initcode_start, (uint64)_binary_initcode_size); p->sz = PGSIZE; memset(p->tf, 0, sizeof(*p->tf)); + p->tf->cs = UCSEG | 0x3; + p->tf->ss = UDSEG | 0x3; p->tf->r11 = FL_IF; p->tf->rsp = PGSIZE; p->tf->rcx = 0; // beginning of initcode.S @@ -321,12 +330,12 @@ scheduler(void) { struct proc *p; struct cpu *c = mycpu(); + c->proc = 0; - for(;;){ // Enable interrupts on this processor. sti(); - + // Loop over process table looking for process to run. acquire(&ptable.lock); for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){ @@ -336,7 +345,6 @@ scheduler(void) // Switch to chosen process. It is the process's job // to release ptable.lock and then reacquire it // before jumping back to us. - c->proc = p; switchuvm(p); p->state = RUNNING; @@ -22,7 +22,7 @@ alltraps: push %rbx push %rax - cmpw $KCSEG, 32(%rsp) # compare to saved cs + cmpw $KCSEG, 144(%rsp) # compare to saved cs jz 1f swapgs @@ -33,7 +33,7 @@ alltraps: .globl trapret trapret: cli - cmpw $KCSEG, 32(%rsp) # compare to saved cs + cmpw $KCSEG, 144(%rsp) # compare to saved cs jz 1f swapgs @@ -72,12 +72,12 @@ sysentry: # Build trap frame. movq %rax, %rsp movq %gs:0, %rax // restore rax - // push usp - push $0 + // push usp to make a valid trapframe + push $(UDSEG|0x3) push %gs:8 // safe eflags and eip push %r11 - push $UCSEG + push $(UCSEG|0x3) push %rcx // push errno and trapno to make stack look like a trap push $0 @@ -130,6 +130,7 @@ sysexit: add $(5*8), %rsp # discard trapnum, errorcode, rip, cs and rflags mov (%rsp),%rsp # switch to the user stack + # there are two more values on the stack, but we don't care about them swapgs sysretq |