kern/src/arsc.c

   1 /* See COPYRIGHT for copyright information. */
   2
   3 #include <ros/common.h>
   4 #include <ros/ring_syscall.h>
   5 #include <arch/types.h>
   6 #include <arch/arch.h>
   7 #include <arch/mmu.h>
   8 #include <error.h>
   9
  10 #include <syscall.h>
  11 #include <kmalloc.h>
  12 #include <pmap.h>
  13 #include <stdio.h>
  14 #include <hashtable.h>
  15 #include <smp.h>
  16 #include <arsc_server.h>
  17 #include <kref.h>
  18
  19
  20
  21 struct proc_list arsc_proc_list = TAILQ_HEAD_INITIALIZER(arsc_proc_list);
  22 spinlock_t arsc_proc_lock = SPINLOCK_INITIALIZER_IRQSAVE;
  23
  24 intreg_t inline syscall_async(struct proc *p, syscall_req_t *call)
  25 {
  26         struct syscall* sc = call->sc;
  27         return syscall(p, sc->num, sc->arg0, sc->arg1,
  28                        sc->arg2, sc->arg3, sc->arg4, sc->arg5);
  29 }
  30
  31 syscall_sring_t* sys_init_arsc(struct proc *p)
  32 {
  33         kref_get(&p->p_kref, 1);                /* we're storing an external ref here */
  34         syscall_sring_t* sring;
  35         void * va;
  36         // TODO: need to pin this page in the future when swapping happens
  37         va = do_mmap(p,MMAP_LOWEST_VA, SYSCALLRINGSIZE, PROT_READ | PROT_WRITE,
  38                      MAP_ANONYMOUS | MAP_POPULATE, NULL, 0);
  39         pte_t pte = pgdir_walk(p->env_pgdir, (void*)va, 0);
  40         assert(pte_walk_okay(pte));
  41         sring = (syscall_sring_t*) KADDR(pte_get_paddr(pte));
  42         /*make sure we are able to allocate the shared ring */
  43         assert(sring != NULL);
  44         p->procdata->syscallring = sring;
  45         /* Initialize the generic syscall ring buffer */
  46         SHARED_RING_INIT(sring);
  47
  48         BACK_RING_INIT(&p->syscallbackring,
  49                        sring,
  50                        SYSCALLRINGSIZE);
  51
  52         spin_lock_irqsave(&arsc_proc_lock);
  53         TAILQ_INSERT_TAIL(&arsc_proc_list, p, proc_arsc_link);
  54         spin_unlock_irqsave(&arsc_proc_lock);
  55         return (syscall_sring_t*)va;
  56 }
  57
  58 void arsc_server(uint32_t srcid, long a0, long a1, long a2)
  59 {
  60         struct proc *p = NULL;
  61         TAILQ_INIT(&arsc_proc_list);
  62         while (1) {
  63                 while (TAILQ_EMPTY(&arsc_proc_list))
  64                         cpu_relax();
  65
  66                 TAILQ_FOREACH(p, &arsc_proc_list, proc_arsc_link) {
  67                         /* Probably want to try to process a dying process's syscalls.  If
  68                          * not, just move it to an else case */
  69                         process_generic_syscalls (p, MAX_ASRC_BATCH);
  70                         if (proc_is_dying(p)) {
  71                                 TAILQ_REMOVE(&arsc_proc_list, p, proc_arsc_link);
  72                                 proc_decref(p);
  73                                 /* Need to break out, so the TAILQ_FOREACH doesn't flip out.
  74                                  * It's not fair, but we're not dealing with that yet anyway */
  75                                 break;
  76                         }
  77                 }
  78         }
  79 }
  80
  81 static intreg_t process_generic_syscalls(struct proc *p, size_t max)
  82 {
  83         size_t count = 0;
  84         syscall_back_ring_t* sysbr = &p->syscallbackring;
  85         struct per_cpu_info* pcpui = &per_cpu_info[core_id()];
  86         uintptr_t old_proc;
  87         // looking at a process not initialized to perform arsc.
  88         if (sysbr == NULL)
  89                 return count;
  90         /* Bail out if there is nothing to do */
  91         if (!RING_HAS_UNCONSUMED_REQUESTS(sysbr))
  92                 return 0;
  93         /* Switch to the address space of the process, so we can handle their
  94          * pointers, etc. */
  95         old_proc = switch_to(p);
  96         // max is the most we'll process.  max = 0 means do as many as possible
  97         // TODO: check for initialization of the ring.
  98         while (RING_HAS_UNCONSUMED_REQUESTS(sysbr) && ((!max)||(count < max)) ) {
  99                 // ASSUME: one queue per process
 100                 count++;
 101                 //printk("DEBUG PRE: sring->req_prod: %d, sring->rsp_prod: %d\n",
 102                 //         sysbr->sring->req_prod, sysbr->sring->rsp_prod);
 103                 // might want to think about 0-ing this out, if we aren't
 104                 // going to explicitly fill in all fields
 105                 syscall_rsp_t rsp;
 106                 // this assumes we get our answer immediately for the syscall.
 107                 syscall_req_t* req = RING_GET_REQUEST(sysbr, ++sysbr->req_cons);
 108
 109                 pcpui->cur_kthread->sysc = req->sc;
 110                 run_local_syscall(req->sc); // TODO: blocking call will block arcs as well.
 111
 112                 // need to keep the slot in the ring buffer if it is blocked
 113                 (sysbr->rsp_prod_pvt)++;
 114                 req->status = RES_ready;
 115                 RING_PUSH_RESPONSES(sysbr);
 116
 117                 //printk("DEBUG POST: sring->req_prod: %d, sring->rsp_prod: %d\n",
 118                 //         sysbr->sring->req_prod, sysbr->sring->rsp_prod);
 119         }
 120         /* switch back to whatever context we were in before */
 121         switch_back(p, old_proc);
 122         return (intreg_t)count;
 123 }
 124