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; }