struct buf * geteblk_special(size_t size, uint32_t control)
{
struct proc_info * p = proc_get_struct(0);
const uintptr_t paddr = get_ksect_addr(size);
struct vm_pt * vpt;
struct buf * buf;
if (!p)
panic("Can't get the PCB of pid 0");
if (paddr == 0)
return NULL;
buf = proc_newsect(paddr, size, VM_PROT_READ | VM_PROT_WRITE);
if (!buf)
return buf;
buf->b_mmu.control = control;
vpt = ptlist_get_pt(&p->mm.ptlist_head, &p->mm.mpt,
buf->b_mmu.vaddr);
if (!vpt) {
panic("Mapping a kernel special buffer failed");
}
buf->b_mmu.pt = &vpt->pt;
vm_map_region(buf, vpt);
vm_add_region(&p->mm, buf);
buf->b_data = buf->b_mmu.vaddr;
return buf;
}
static pthread_t create_uinit_main(void * stack_addr)
{
struct _sched_pthread_create_args init_ds = {
.param.sched_policy = SCHED_OTHER,
.param.sched_priority = NZERO,
.stack_addr = stack_addr,
.stack_size = configUSRINIT_SSIZE,
.flags = 0,
.start = uinit, /* We have to first get into user space to use exec
* and mount the rootfs.
*/
.arg1 = (uintptr_t)rootfs,
.del_thread = (void (*)(void *))uinit_exit,
};
return thread_create(&init_ds, THREAD_MODE_PRIV);
}
/**
* Map vmstack to proc.
*/
static void map_vmstack2proc(struct proc_info * proc, struct buf * vmstack)
{
struct vm_pt * vpt;
(*proc->mm.regions)[MM_STACK_REGION] = vmstack;
vm_updateusr_ap(vmstack);
vpt = ptlist_get_pt(&proc->mm, vmstack->b_mmu.vaddr,
MMU_PGSIZE_COARSE, VM_PT_CREAT);
if (vpt == 0)
panic("Couldn't get vpt for init stack");
vmstack->b_mmu.pt = &(vpt->pt);
vm_map_region(vmstack, vpt);
}
/**
* Create init process.
*/
int __kinit__ kinit(void)
{
SUBSYS_DEP(sched_init);
SUBSYS_DEP(proc_init);
SUBSYS_DEP(ramfs_init);
SUBSYS_DEP(sysctl_init);
SUBSYS_INIT("kinit");
char strbuf[80]; /* Buffer for panic messages. */
struct buf * init_vmstack;
pthread_t tid;
pid_t pid;
struct thread_info * init_thread;
struct proc_info * init_proc;
/*
* FIXME Memory allocation, protection or manipulation bug!
* There is a critical bug causing random crashes in userland. I suspect
* something is overwriting user space allocation from the kernel space.
* Allocating some memory before init is executed seems to fix this issue,
* however naturally this is not the proper way to fix the bug.
* Without the allocation here the issue is sometimes seen in init or
* usually after couple of fork + exec + exit cycles. The usual symptom is
* that the userland app first calls some 0:0 syscalls and then tries to
* execute undefined instruction, which probably means that either some
* jump table in the heap or some part of the executable code is modified
* by a bad access in kernel mode just before this happens.
*/
(void)geteblk(MMU_PGSIZE_COARSE * 10);
mount_tmp_rootfs();
/*
* User stack for init
*/
init_vmstack = create_vmstack();
if (!init_vmstack)
panic("Can't allocate a stack for init");
/*
* Create a thread for init
*/
tid = create_uinit_main((void *)(init_vmstack->b_mmu.paddr));
if (tid < 0) {
ksprintf(strbuf, sizeof(strbuf), "Can't create a thread for init. %i",
tid);
panic(strbuf);
}
/*
* pid of init
*/
pid = proc_fork();
if (pid <= 0) {
ksprintf(strbuf, sizeof(strbuf), "Can't fork a process for init. %i",
pid);
panic(strbuf);
}
init_thread = thread_lookup(tid);
if (!init_thread) {
panic("Can't get thread descriptor of init_thread!");
}
init_proc = proc_ref(pid);
if (!init_proc || (init_proc->state == PROC_STATE_INITIAL)) {
panic("Failed to get proc struct or invalid struct");
}
init_thread->pid_owner = pid;
init_thread->curr_mpt = &init_proc->mm.mpt;
/*
* Map the previously created user stack with init process page table.
*/
map_vmstack2proc(init_proc, init_vmstack);
/*
* Map tkstack of init with vm_pagetable_system.
*/
mmu_map_region(&init_thread->kstack_region->b_mmu);
init_proc->main_thread = init_thread;
KERROR_DBG("Init created with pid: %u, tid: %u, stack: %p\n",
pid, tid, (void *)init_vmstack->b_mmu.vaddr);
proc_unref(init_proc);
return 0;
}
