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#include "kernel/proc.h"
#include "kernel/pmm.h"
#include "kernel/mm.h"
#include "drivers/uart.h"
#include "kernel/trap.h"
#include "common/types.h"
#include "kernel/riscv.h"
#include "kernel/config.h"
#define NPROC 10
extern "C" void swtch(struct Context *old_ctx, struct Context *new_ctx);
extern char uservec[];
extern "C" void userret(uint64, uint64);
extern char trampoline[];
extern void *memset(void *dst, int c, uint n);
struct Proc procs[NPROC];
struct Context main_context;
struct Proc *current_proc = nullptr;
void str_copy(char *dst, const char *src)
{
while (*src)
*dst++ = *src++;
*dst = 0;
}
uchar initcode[] = {
0x13, 0x05, 0x50, 0x05, // li a0, 85 ('U')
0x93, 0x08, 0x10, 0x00, // li a7, 1 (SYS_putc)
0x73, 0x00, 0x00, 0x00, // ecall
0x6f, 0xf0, 0x5f, 0xff // j loop (-12)
};
struct Proc *myproc()
{
return current_proc;
}
void usertrapret()
{
struct Proc *p = myproc();
asm volatile("csrc sstatus, %0" : : "r"(SSTATUS_SIE));
uint64 trampoline_uservec = TRAMPOLINE + (uservec - trampoline);
asm volatile("csrw stvec, %0" : : "r"(trampoline_uservec));
p->tf->kernel_satp = r_satp();
p->tf->kernel_sp = (uint64)p->kstack + PGSIZE;
p->tf->kernel_trap = (uint64)usertrap;
p->tf->kernel_hartid = r_tp();
unsigned long x = r_sstatus();
x &= ~SSTATUS_SPP;
x |= SSTATUS_SPIE;
w_sstatus(x);
w_sepc(p->tf->epc);
uint64 satp = MAKE_SATP(p->pagetable);
uint64 fn = TRAMPOLINE + ((uint64)userret - (uint64)trampoline);
((void (*)(uint64, uint64))fn)(TRAPFRAME, satp);
}
void forkret()
{
//....
usertrapret();
}
namespace ProcManager
{
void init()
{
for (int i = 0; i < NPROC; i++)
{
procs[i].state = UNUSED;
procs[i].kstack = 0;
}
}
void create_kernel_thread(void (*func)(), const char *name)
{
struct Proc *p = nullptr;
for(int i = 0; i < NPROC; i++)
{
if(procs[i].state == UNUSED)
{
p = &procs[i];
p->pid = i + 1;
break;
}
}
if (!p)
{
Drivers::uart_puts("Error: No free process slots!\n");
return;
}
p->kstack = PMM::alloc_page();
if (!p->kstack)
{
Drivers::uart_puts("Error: Alloc kstack failed!\n");
return;
}
p->context.ra = (uint64)func;
p->context.sp = (uint64)p->kstack + 4096;
p->state = RUNNABLE;
str_copy(p->name, name);
Drivers::uart_puts("[Proc] Created thread: ");
Drivers::uart_puts(name);
Drivers::uart_puts("\n");
}
void yield()
{
struct Proc *p = myproc();
if (p && p->state == RUNNING)
{
p->state = RUNNABLE;
swtch(&p->context, &main_context);
}
}
void scheduler()
{
struct Proc *p = nullptr;
Drivers::uart_puts("[Proc] Scheduler started.\n");
for (;;)
{
int nothing_found = 1;
intr_on();
for (p = procs; p < &procs[NPROC]; p++)
{
if (p->state == RUNNABLE)
{
nothing_found = 0;
p->state = RUNNING;
current_proc = p;
swtch(&main_context, &p->context);
current_proc = nullptr;
}
}
if (nothing_found)
{
asm volatile("wfi");
}
}
}
void user_init()
{
struct Proc *p = nullptr;
for(int i = 0; i < NPROC; ++i)
{
if(procs[i].state == UNUSED)
{
p = &procs[i];
p->pid = i + 1;
break;
}
}
if (!p)
{
Drivers::uart_puts("user_init: no free procs\n");
return;
}
p->kstack = PMM::alloc_page();
if (p->kstack == 0)
{
Drivers::uart_puts("user_init: kstack alloc failed\n");
return;
}
p->tf = (struct Trapframe*)PMM::alloc_page();
if (p->tf == 0)
{
Drivers::uart_puts("user_init: tf alloc failed\n");
return;
}
memset(p->tf, 0, PGSIZE);
p->pagetable = VM::uvmcreate();
// if (VM::mappages(p->pagetable, TRAMPOLINE, PGSIZE,
// (uint64)trampoline, PTE_R | PTE_X) < 0)
// {
// Drivers::uart_puts("user_init: map trampoline failed\n");
// return;
// }
if (VM::mappages(p->pagetable, TRAPFRAME, PGSIZE,
(uint64)p->tf, PTE_R | PTE_W) < 0)
{
Drivers::uart_puts("user_init: map trapframe failed\n");
return;
}
VM::uvminit(p->pagetable, initcode, sizeof(initcode));
p->sz = PGSIZE;
p->tf->epc = 0;
p->tf->sp = PGSIZE;
memset(&p->context, 0, sizeof(p->context));
p->context.ra = (uint64)forkret;
p->context.sp = (uint64)p->kstack + PGSIZE;
p->state = RUNNABLE;
const char *name = "initcode";
for (int i = 0; name[i] && i < 15; i++)
p->name[i] = name[i];
Drivers::uart_puts("[Proc] user_init success. PID: 1\n");
}
}
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