diff options
Diffstat (limited to 'sys/kern/kern_sched.c')
| -rw-r--r-- | sys/kern/kern_sched.c | 490 |
1 files changed, 0 insertions, 490 deletions
diff --git a/sys/kern/kern_sched.c b/sys/kern/kern_sched.c deleted file mode 100644 index ddc99ca..0000000 --- a/sys/kern/kern_sched.c +++ /dev/null @@ -1,490 +0,0 @@ -/* - * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team. - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions are met: - * - * 1. Redistributions of source code must retain the above copyright notice, - * this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. Neither the name of Hyra nor the names of its - * contributors may be used to endorse or promote products derived from - * this software without specific prior written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" - * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE - * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR - * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF - * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS - * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN - * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) - * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE - * POSSIBILITY OF SUCH DAMAGE. - */ - -#include <sys/sched.h> -#include <sys/schedvar.h> -#include <sys/machdep.h> -#include <sys/loader.h> -#include <sys/errno.h> -#include <sys/cdefs.h> -#include <sys/filedesc.h> -#include <sys/timer.h> -#include <sys/panic.h> -#include <sys/signal.h> -#include <fs/initramfs.h> -#include <vm/dynalloc.h> -#include <vm/physseg.h> -#include <vm/map.h> -#include <vm/pmap.h> -#include <string.h> -#include <assert.h> - -/* - * Thread ready queues - all threads ready to be - * scheduled should be added to the toplevel queue. - */ -static struct sched_queue qlist[SCHED_NQUEUE]; - -/* - * Global scheduler state. - */ -static size_t nthread = 0; -static schedpolicy_t policy = SCHED_POLICY_MLFQ; - -/* - * Thread queue lock - all operations to `qlist' - * must be done with this lock acquired. - * - * This lock is aligned on a cache line boundary to ensure - * it has its own cache line to reduce contention. This is - * because it is constantly acquired and released on every - * processor. - */ -__cacheline_aligned -static struct spinlock tdq_lock = {0}; - -/* - * Lower thread priority. - */ -static inline void -td_pri_lower(struct proc *td) -{ - if (td->priority < (SCHED_NQUEUE - 1)) - ++td->priority; -} - -/* - * Raise thread priority. - */ -static inline void -td_pri_raise(struct proc *td) -{ - if (td->priority > 0) - --td->priority; -} - -/* - * Called during preemption. We raise the priority - * if the thread has been rested. If the thread has not - * been rested, we lower its priority. - */ -static void -td_pri_update(struct proc *td) -{ - if (td->rested) { - td->rested = 0; - td_pri_raise(td); - return; - } - - td_pri_lower(td); -} - -/* - * Enqueue a thread into the scheduler. - */ -static void -sched_enqueue_td(struct proc *td) -{ - struct sched_queue *queue; - - spinlock_acquire(&tdq_lock); - queue = &qlist[td->priority]; - - TAILQ_INSERT_TAIL(&queue->q, td, link); - spinlock_release(&tdq_lock); -} - -/* - * Dequeue a thread from a queue. - */ -static struct proc * -sched_dequeue_td(void) -{ - struct sched_queue *queue; - struct proc *td = NULL; - - spinlock_acquire(&tdq_lock); - - /* - * Try to pop a thread from a queue. We start at the - * highest priority which is 0. - */ - for (size_t i = 0; i < SCHED_NQUEUE; ++i) { - queue = &qlist[i]; - - if (!TAILQ_EMPTY(&queue->q)) { - td = TAILQ_FIRST(&queue->q); - TAILQ_REMOVE(&queue->q, td, link); - break; - } - } - - spinlock_release(&tdq_lock); - return td; -} - -/* - * Create a new thread stack. - * sched_new_td() helper. - */ -static uintptr_t -sched_create_stack(bool is_user, struct exec_args args, struct proc *td) -{ - int status; - uintptr_t stack; - struct vm_range *stack_range; - const vm_prot_t USERSTACK_PROT = PROT_WRITE | PROT_USER; - - stack_range = &td->addr_range[ADDR_RANGE_STACK]; - - /* - * Kernel stacks can be allocated with dynalloc() as they - * are on the higher half. - */ - if (!is_user) { - stack = (uintptr_t)dynalloc(PROC_STACK_SIZE); - stack_range->start = stack; - stack_range->end = stack + PROC_STACK_SIZE; - return loader_init_stack((void *)(stack + PROC_STACK_SIZE), args); - } - - stack = vm_alloc_pageframe(PROC_STACK_PAGES); - if (stack == 0) { - return 0; - } - - status = vm_map_create(args.vas, stack, stack, USERSTACK_PROT, PROC_STACK_SIZE); - if (status != 0) { - vm_free_pageframe(stack, PROC_STACK_PAGES); - return 0; - } - - stack_range->start = stack; - stack_range->end = stack + PROC_STACK_SIZE; - - memset(USER_TO_KERN(stack), 0, PROC_STACK_SIZE); - stack = loader_init_stack((void *)USER_TO_KERN(stack + PROC_STACK_SIZE), args); - return stack; -} - -/* - * Create a new thread. - * - * @ip: Instruction pointer to start at. - * @is_user: True for user program. - * @exec_args: Common exec args. - */ -static int -sched_new_td(uintptr_t ip, bool is_user, struct exec_args args, struct vm_range *prog_range, - struct proc **res) -{ - struct vm_range *exec_range; - struct proc *td; - struct trapframe *tf; - uintptr_t stack; - int retval = 0; - - td = dynalloc(sizeof(struct proc)); - tf = dynalloc(sizeof(struct trapframe)); - if (td == NULL || tf == NULL) { - retval = -ENOMEM; - goto done; - } - - /* Keep them in a known state */ - memset(td, 0, sizeof(*td)); - memset(tf, 0, sizeof(*tf)); - - /* Try to create a stack */ - stack = sched_create_stack(is_user, args, td); - if (stack == 0) { - retval = -ENOMEM; - goto done; - } - - /* Setup initial thread state */ - td->pid = ++nthread; - td->tf = tf; - td->addrsp = args.vas; - td->is_user = is_user; - processor_init_pcb(td); - - /* Setup each mapping table */ - for (size_t i = 0; i < MTAB_ENTRIES; ++i) { - TAILQ_INIT(&td->mapspace.mtab[i]); - } - - /* Setup standard file descriptors */ - __assert(fd_alloc(td, NULL) == 0); /* STDIN */ - __assert(fd_alloc(td, NULL) == 0); /* STDOUT */ - __assert(fd_alloc(td, NULL) == 0); /* STDERR */ - - exec_range = &td->addr_range[ADDR_RANGE_EXEC]; - memcpy(exec_range, prog_range, sizeof(struct vm_range)); - - /* Init the trapframe */ - if (!is_user) { - init_frame(tf, ip, stack); - } else { - init_frame_user(tf, ip, KERN_TO_USER(stack)); - } -done: - if (retval != 0 && td != NULL) - dynfree(td); - if (retval != 0 && tf != NULL) - dynfree(td); - if (retval == 0 && res != NULL) - *res = td; - - return retval; -} - -/* - * Perform timer oneshot - * - * @now: True for shortest timeslice. - */ -static inline void -sched_oneshot(bool now) -{ - struct timer timer; - size_t usec = (now) ? SHORT_TIMESLICE_USEC : DEFAULT_TIMESLICE_USEC; - tmrr_status_t tmr_status; - - tmr_status = req_timer(TIMER_SCHED, &timer); - __assert(tmr_status == TMRR_SUCCESS); - - timer.oneshot_us(usec); -} - -/* - * Enter the schedulera and wait until - * preemption. - */ -void -sched_enter(void) -{ - sched_oneshot(false); - - for (;;) { - hint_spinwait(); - } -} - -/* - * Initialize all of the queues. - */ -static void -sched_init_queues(void) -{ - for (size_t i = 0; i < SCHED_NQUEUE; ++i) { - TAILQ_INIT(&qlist[i].q); - } -} - -/* - * Load the first thread (init) - */ -static void -sched_load_init(void) -{ - struct exec_args args; - struct proc *init; - struct auxval *auxvp = &args.auxv; - struct vm_range init_range; - int tmp; - - char *argv[] = {"/usr/sbin/init", NULL}; - char *envp[] = {NULL}; - const char *init_bin; - - if ((init_bin = initramfs_open("/usr/sbin/init")) == NULL) - panic("Could not open /usr/sbin/init\n"); - - pmap_create_vas(vm_get_ctx(), &args.vas); - args.argp = argv; - args.envp = envp; - - tmp = loader_load(args.vas, init_bin, auxvp, 0, NULL, &init_range); - if (tmp != 0) - panic("Failed to load init\n"); - - if (sched_new_td(auxvp->at_entry, true, args, &init_range, &init) != 0) - panic("Failed to create init thread\n"); - - sched_enqueue_td(init); -} - -static void -sched_destroy_td(struct proc *td) -{ - struct vm_range *stack_range; - struct vm_range *exec_range; - vm_mapq_t *mapq; - - processor_free_pcb(td); - stack_range = &td->addr_range[ADDR_RANGE_STACK]; - exec_range = &td->addr_range[ADDR_RANGE_EXEC]; - - /* - * User thread's have their stack allocated - * with vm_alloc_pageframe() and kernel thread's - * have their stacks allocated with dynalloc() - */ - if (td->is_user) { - vm_free_pageframe(stack_range->start, PROC_STACK_PAGES); - } else { - dynfree((void *)stack_range->start); - } - - for (size_t i = 0; i < MTAB_ENTRIES; ++i) { - mapq = &td->mapspace.mtab[i]; - vm_free_mapq(mapq); - } - - for (size_t i = 0; i < PROC_MAX_FDS; ++i) { - fd_close_fdnum(td, i); - } - - loader_unload(td->addrsp, exec_range); - pmap_free_vas(vm_get_ctx(), td->addrsp); - dynfree(td); -} - -/* - * Cause an early preemption and lets - * the next thread run. - */ -void -sched_rest(void) -{ - struct proc *td = this_td(); - - if (td == NULL) - return; - - td->rested = 1; - sched_oneshot(true); -} - -void -sched_exit(void) -{ - struct proc *td = this_td(); - struct vas kvas = vm_get_kvas(); - - spinlock_acquire(&tdq_lock); - intr_mask(); - - /* Switch to kernel VAS and destroy td */ - pmap_switch_vas(vm_get_ctx(), kvas); - sched_destroy_td(td); - - spinlock_release(&tdq_lock); - intr_unmask(); - sched_enter(); -} - -/* - * Get the current running thread. - */ -struct proc * -this_td(void) -{ - struct sched_state *state; - struct cpu_info *ci; - - ci = this_cpu(); - state = &ci->sched_state; - return state->td; -} - -/* - * Thread context switch routine - * - * Handles the transition from the currently running - * thread to the next thread. - */ -void -sched_context_switch(struct trapframe *tf) -{ - struct cpu_info *ci = this_cpu(); - struct sched_state *state = &ci->sched_state; - struct proc *next_td, *td = state->td; - - if (td != NULL) { - signal_handle(state->td); - } - - /* - * If a thread is currently running and our policy is - * MLFQ, then we should update the thread's priority. - */ - if (td != NULL && policy == SCHED_POLICY_MLFQ) { - td_pri_update(td); - } - - /* Don't preempt if we have no threads */ - if ((next_td = sched_dequeue_td()) == NULL) { - sched_oneshot(false); - return; - } - - /* - * If we have a thread currently running, then we should save - * its current register state and re-enqueue it. - */ - if (td != NULL) { - memcpy(td->tf, tf, sizeof(struct trapframe)); - sched_enqueue_td(td); - } - - /* Perform the switch */ - memcpy(tf, next_td->tf, sizeof(struct trapframe)); - processor_switch_to(td, next_td); - - state->td = next_td; - pmap_switch_vas(vm_get_ctx(), next_td->addrsp); - sched_oneshot(false); -} - -uint64_t -sys_exit(struct syscall_args *args) -{ - sched_exit(); - __builtin_unreachable(); -} - -void -sched_init(void) -{ - sched_init_queues(); - sched_load_init(); -} |