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#include "scheduler.hpp"
#include "boucane.hpp"
#include "core/apic.hpp"
PROC procs[MAX_TASK];
u32 nproc=0;
char show_ticks=0;
char scheduling=0;
u32 active_process=0;
extern "C" void clock(){
if(show_ticks)
print(".");
if(scheduling)
schedule();
}
void schedule(){
// First get a pointer to the first process saved register.
// Since this is called by clock(), %rbp contains a pointer
// to the clock() %rbp value and then we access to the registers SAVE_REGS in int.S
u64* stack;
asm("mov %%rbp, %%rax;mov (%%rax), %%rbx; add $16, %%rbx; mov %%rbx,%0": "=m"(stack)::"rax","rbx");
// Save current task
PROC *t=&procs[active_process];
t->registers.r8=stack[0];
t->registers.r9=stack[1];
t->registers.r10=stack[2];
t->registers.r11=stack[3];
t->registers.r12=stack[4];
t->registers.r13=stack[5];
t->registers.r14=stack[6];
t->registers.r15=stack[7];
t->registers.rdi=stack[8];
t->registers.rsi=stack[9];
t->registers.rbp=stack[10];
t->registers.rdx=stack[11];
t->registers.rcx=stack[12];
t->registers.rbx=stack[13];
t->registers.rax=stack[14];
t->registers.rip=stack[15];
t->registers.cs=stack[16];
t->registers.eflags=stack[17];
t->registers.rsp=stack[18];
t->registers.ds=stack[19];
// Goto next task
active_process++;
if(active_process>=nproc)
active_process=0;
t=&procs[active_process];
kvar_tss.rsp0=t->registers.rsp0;
// Clock acknownledgement
apic_ack();
asm volatile(
"mov %0, %%rdi \n\t"
"jmp switch \n\t"
:: "a" (t)
);
}
void create_task(void* task, u32 size){
if(nproc>=MAX_TASK){
printk("Could not create more tasks.");
return;
}
PROC *t=&procs[nproc];
t->id=nproc;
t->pid=nproc;
t->size=size;
u32 npages=size%4096 ? size/4096 + 1 : size/4096;
// Note that paging_create_task() allocate 2 more pages (one for the user stack and
// the other for the kernel stack)
t->pml4=paging_create_task(npages);
t->registers.rsp=TASK_VMA+npages*4096+4096; // User stack
t->registers.rsp0=TASK_VMA+npages*4096+4096*2; // Kernel stack on the last page
t->registers.rip=TASK_VMA;
t->registers.cs=0x1B; // 0x18 and 0x3 privilege
t->registers.ds=0x23; // 0x20 and 0x3 privilege
// Load task using
lpml4(t->pml4);
memcpy(task, TASK_VMA, size);
lpml4(kpml4);
nproc++;
}
void scheduler_start(){
scheduling=1;
active_process=0;
PROC *t=&procs[active_process];
kvar_tss.rsp0=t->registers.rsp0;
asm(
"cli \n\t"
"mov %0, %%rdi \n\t"
"jmp switch \n\t"
:: "r" (t)
);
}
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