spin_unlock(&idle_lock);
}
+/* Other helpers, implemented later. */
+static uint32_t get_free_vcoreid(struct proc *SAFE p, uint32_t prev);
+static uint32_t get_busy_vcoreid(struct proc *SAFE p, uint32_t prev);
+static int32_t __get_vcoreid(int32_t *corelist, size_t num, int32_t pcoreid);
+static int32_t get_vcoreid(struct proc *SAFE p, int32_t pcoreid);
+static inline void __wait_for_ipi(const char *fnname);
+
/* PID management. */
#define PID_MAX 32767 // goes from 0 to 32767, with 0 reserved
static DECL_BITMASK(pid_bmask, PID_MAX + 1);
}
/* Returns a pointer to the proc with the given pid, or 0 if there is none */
-/* TODO: handle refcnting */
struct proc *pid2proc(pid_t pid)
{
spin_lock(&pid_hash_lock);
struct proc *p = hashtable_search(pid_hash, (void*)pid);
spin_unlock(&pid_hash_lock);
+ /* if the refcnt was 0, decref and return 0 (we failed). (TODO) */
+ if (p)
+ proc_incref(p, 1); // TODO:(REF) to do this all atomically and not panic
return p;
}
atomic_init(&num_envs, 0);
}
+static void
+proc_init_procinfo(struct proc* p)
+{
+ p->env_procinfo->pid = p->pid;
+ p->env_procinfo->ppid = p->ppid;
+ p->env_procinfo->tsc_freq = system_timing.tsc_freq;
+ // TODO: maybe do something smarter here
+ p->env_procinfo->max_harts = MAX(1,num_cpus); // hack to use all cores
+}
+
/* Allocates and initializes a process, with the given parent. Currently
* writes the *p into **pp, and returns 0 on success, < 0 for an error.
* Errors include:
if (!(p = kmem_cache_alloc(proc_cache, 0)))
return -ENOMEM;
- { INITSTRUCT(*p)
+ { INITSTRUCT(*p)
+
+ // Setup the default map of where to get cache colors from
+ p->cache_colors_map = global_cache_colors_map;
+ p->next_cache_color = 0;
/* Initialize the address space */
if ((r = env_setup_vm(p)) < 0) {
spin_unlock(&pid_hash_lock);
/* Set the basic status variables. */
- spinlock_init(&p->proc_lock);
+ spinlock_init(&p->proc_lock);
+ p->exitcode = 0;
p->ppid = parent_id;
- __proc_set_state(p, PROC_CREATED);
- p->env_refcnt = 1;
+ p->state = PROC_CREATED; // shouldn't go through state machine for init
+ p->env_refcnt = 2; // one for the object, one for the ref we pass back
p->env_flags = 0;
p->env_entry = 0; // cheating. this really gets set in load_icode
p->num_vcores = 0;
+ p->heap_bottom = (void*)UTEXT;
+ p->heap_top = (void*)UTEXT;
memset(&p->vcoremap, -1, sizeof(p->vcoremap));
memset(&p->resources, 0, sizeof(p->resources));
memset(&p->env_ancillary_state, 0, sizeof(p->env_ancillary_state));
memset(&p->env_tf, 0, sizeof(p->env_tf));
- proc_init_trapframe(&p->env_tf);
+ proc_init_trapframe(&p->env_tf,0);
/* Initialize the contents of the e->env_procinfo structure */
- p->env_procinfo->pid = p->pid;
+ proc_init_procinfo(p);
/* Initialize the contents of the e->env_procdata structure */
/* Initialize the generic syscall ring buffer */
*pp = p;
atomic_inc(&num_envs);
- printk("[%08x] new process %08x\n", current ? current->pid : 0, p->pid);
+ proc_init_arch(p);
+
+ printd("[%08x] new process %08x\n", current ? current->pid : 0, p->pid);
} // INIT_STRUCT
return 0;
}
curid = (current ? current->pid : 0);
if ((r = proc_alloc(&p, curid)) < 0)
panic("proc_create: %e", r); // one of 3 quaint usages of %e.
- load_icode(p, binary, size);
+ if(binary != NULL)
+ env_load_icode(p, NULL, binary, size);
return p;
}
{
physaddr_t pa;
- printk("[PID %d] freeing proc: %d\n", current ? current->pid : 0, p->pid);
+ printd("[PID %d] freeing proc: %d\n", current ? current->pid : 0, p->pid);
// All parts of the kernel should have decref'd before __proc_free is called
assert(p->env_refcnt == 0);
+ proc_free_arch(p);
+
+ // Free any colors allocated to this process
+ if(p->cache_colors_map != global_cache_colors_map) {
+ for(int i=0; i<llc_cache->num_colors; i++)
+ cache_color_free(llc_cache, p->cache_colors_map);
+ cache_colors_map_free(p->cache_colors_map);
+ }
+
// Flush all mapped pages in the user portion of the address space
env_user_mem_free(p);
p->env_cr3 = 0;
page_decref(pa2page(pa));
- /* between when someone grabs the *proc (from pid), til they use it, it
- * could be killed and/or deallocated. lots of our protections come from
- * the state, which needs to be dereferenced, and isn't protected from this.
- *
- * (TODO) rule: when you get a *proc, you up the refcnt. need to down it
- * when you are done. if you fail, someone else is deallocating it. you
- * shouldn't have dereferenced it (it may be 'gone' already), so there is a
- * slight race, but if you do this check quickly, it's *probably* not an
- * issue. so do it with interrupts off. pid2proc will handle that, but you
- * need to decref still
- * - getting the pointer from current is a refcnt'd source. when current is
- * set, the refcnt is up anyway (for protecting the page tables), so just
- * use it normally.
- * - if you pass the pointer (via amsg, etc), the code that uses it should
- * up its refcnt or otherwise deal with the issue (which startcore should
- * do), though this might need to change. (freed and realloc before the
- * message arrives). perhaps up the refcnt in advance, and down it if it
- * was unnecessary (TODO).
- * - if the pointer is stored somewhere (like in an IO continuation), the
- * refcnt needs to stay up.
- * - can check for DYING too, though some situations may want to grab a
- * dying proc's *
- * - i am not concerned with pointing to a new proc with that same PID, the
- * concern is with referencing kernel memory.
- * Might move this to proc_destroy. depends if we want parents to wait().
- */
/* Remove self from the pid hash, return PID. Note the reversed order. */
spin_lock(&pid_hash_lock);
if (!hashtable_remove(pid_hash, (void*)p->pid))
* When a process goes from RUNNABLE_M to RUNNING_M, its vcoremap will be
* "packed" (no holes in the vcore->pcore mapping), vcore0 will continue to run
* it's old core0 context, and the other cores will come in at the entry point.
- * Including in the case of preemption. */
+ * Including in the case of preemption.
+ *
+ * This won't return if the current core is going to be one of the processes
+ * cores (either for _S mode or for _M if it's in the vcoremap). proc_run will
+ * eat your reference if it does not return. */
void proc_run(struct proc *p)
{
+ bool self_ipi_pending = FALSE;
spin_lock_irqsave(&p->proc_lock);
switch (p->state) {
case (PROC_DYING):
spin_unlock_irqsave(&p->proc_lock);
printk("Process %d not starting due to async death\n", p->pid);
- // There should be no core cleanup to do (like decref).
- assert(current != p);
// if we're a worker core, smp_idle, o/w return
if (!management_core())
smp_idle(); // this never returns
p->num_vcores = 0;
p->vcoremap[0] = core_id();
spin_unlock_irqsave(&p->proc_lock);
- // This normally doesn't return, but might error out in the future.
+ /* Transferring our reference to startcore, where p will become
+ * current. If it already is, decref in advance. This is similar
+ * to __startcore(), in that it sorts out the refcnt accounting. */
+ if (current == p)
+ proc_decref(p, 1);
proc_startcore(p, &p->env_tf);
break;
case (PROC_RUNNABLE_M):
- __proc_set_state(p, PROC_RUNNING_M);
/* vcoremap[i] holds the coreid of the physical core allocated to
* this process. It is set outside proc_run. For the active
* message, a0 = struct proc*, a1 = struct trapframe*. */
if (p->num_vcores) {
+ __proc_set_state(p, PROC_RUNNING_M);
int i = 0;
+ /* Up the refcnt, since num_vcores are going to start using this
+ * process and have it loaded in their 'current'. */
+ p->env_refcnt += p->num_vcores; // TODO: (REF) use incref
+ /* If the core we are running on is in the vcoremap, we will get
+ * an IPI (once we reenable interrupts) and never return. */
+ if (__get_vcoreid(p->vcoremap, p->num_vcores, core_id()) != -1)
+ self_ipi_pending = TRUE;
// TODO: handle silly state (HSS)
// set virtual core 0 to run the main context on transition
if (p->env_flags & PROC_TRANSITION_TO_M) {
send_active_message(p->vcoremap[i], (void *)__startcore,
(void *)p, (void *)0, (void *)i);
#endif
+ } else {
+ warn("Tried to proc_run() an _M with no vcores!");
}
- /* There a subtle (attempted) race avoidance here. proc_startcore
- * can handle a death message, but we can't have the startcore come
- * after the death message. Otherwise, it would look like a new
- * process. So we hold the lock to make sure our message went out
- * before a possible death message.
+ /* Unlock and decref/wait for the IPI if one is pending. This will
+ * eat the reference if we aren't returning.
+ *
+ * There a subtle race avoidance here. proc_startcore can handle a
+ * death message, but we can't have the startcore come after the
+ * death message. Otherwise, it would look like a new process. So
+ * we hold the lock til after we send our message, which prevents a
+ * possible death message.
* - Likewise, we need interrupts to be disabled, in case one of the
* messages was for us, and reenable them after letting go of the
* lock. This is done by spin_lock_irqsave, so be careful if you
* change this.
- * - This can also be done far more intelligently / efficiently,
- * like skipping in case it's busy and coming back later.
* - Note there is no guarantee this core's interrupts were on, so
* it may not get the message for a while... */
- spin_unlock_irqsave(&p->proc_lock);
+ __proc_unlock_ipi_pending(p, self_ipi_pending);
break;
default:
spin_unlock_irqsave(&p->proc_lock);
}
}
-/*
- * Runs the given context (trapframe) of process p on the core this code
- * executes on. The refcnt tracks how many cores have "an interest" in this
- * process, which so far just means it uses the process's page table. See the
- * massive comments around the incref function
+/* Runs the given context (trapframe) of process p on the core this code
+ * executes on.
*
* Given we are RUNNING_*, an IPI for death or preemption could come in:
* 1. death attempt (IPI to kill whatever is on your core):
* I think we need to make it such that the kernel in "process context" never
* gets removed from the core (displaced from its stack) without going through
* some "bundling" code.
- */
+ *
+ * A note on refcnting: this function will not return, and your proc reference
+ * will end up stored in current. This will make no changes to p's refcnt, so
+ * do your accounting such that there is only the +1 for current. This means if
+ * it is already in current (like in the trap return path), don't up it. If
+ * it's already in current and you have another reference (like pid2proc or from
+ * an IPI), then down it (which is what happens in __startcore()). If it's not
+ * in current and you have one reference, like proc_run(non_current_p), then
+ * also do nothing. The refcnt for your *p will count for the reference stored
+ * in current. */
void proc_startcore(struct proc *p, trapframe_t *tf) {
// it's possible to be DYING, but it's a rare race.
//if (p->state & (PROC_RUNNING_S | PROC_RUNNING_M))
}
/* If the process wasn't here, then we need to load its address space. */
if (p != current) {
- if (proc_incref(p)) {
- // getting here would mean someone tried killing this while we tried
- // to start one of it's contexts (from scratch, o/w we had it's CR3
- // loaded already)
- // if this happens, a no-op death-IPI ought to be on its way... we can
- // just smp_idle()
- smp_idle();
- }
+ /* Do not incref here. We were given the reference to current,
+ * pre-upped. */
lcr3(p->env_cr3);
- // we unloaded the old cr3, so decref it (if it exists)
- // TODO: Consider moving this to wherever we really "mean to leave the
- // process's context". abandon_core() does this.
+ /* This is "leaving the process context" of the previous proc. The
+ * previous lcr3 unloaded the previous proc's context. This should
+ * rarely happen, since we usually proactively leave process context,
+ * but is the fallback. */
if (current)
- proc_decref(current);
+ proc_decref(current, 1);
set_current_proc(p);
}
/* need to load our silly state, preferably somewhere other than here so we
env_pop_tf(tf);
}
-/* Helper function, helps with receiving local death IPIs, for the cases when
- * this core is running the process. We should received an IPI shortly. If
- * not, odds are interrupts are disabled, which shouldn't happen while servicing
- * syscalls. */
-static void check_for_local_death(struct proc *p)
-{
- if (current == p) {
- /* a death IPI should be on its way, either from the RUNNING_S one, or
- * from proc_take_cores with a __death. in general, interrupts should
- * be on when you call proc_destroy locally, but currently aren't for
- * all things (like traphandlers). since we're dying anyway, it seems
- * reasonable to turn on interrupts. note this means all non-proc
- * management interrupt handlers must return (which they need to do
- * anyway), so that we get back to this point. Eventually, we can
- * remove the enable_irq. think about this (TODO) */
- enable_irq();
- udelay(1000000);
- panic("Waiting too long on core %d for an IPI in proc_destroy()!",
- core_id());
- }
-}
-
/*
* Destroys the given process. This may be called from another process, a light
* kernel thread (no real process context), asynchronously/cross-core, or from
* (Last core/kernel thread to decref cleans up and deallocates resources.)
*
* Note that some cores can be processing async calls, but will eventually
- * decref. Should think about this more.
- */
+ * decref. Should think about this more, like some sort of callback/revocation.
+ *
+ * This will eat your reference if it won't return. Note that this function
+ * needs to change anyways when we make __death more like __preempt. (TODO) */
void proc_destroy(struct proc *p)
{
- // Note this code relies on this lock disabling interrupts, similar to
- // proc_run.
+ /* TODO: this corelist is taking up a lot of space on the stack */
uint32_t corelist[MAX_NUM_CPUS];
size_t num_cores_freed;
+ bool self_ipi_pending = FALSE;
spin_lock_irqsave(&p->proc_lock);
+
+ /* TODO: (DEATH) look at this again when we sort the __death IPI */
+ if (current == p)
+ self_ipi_pending = TRUE;
+
switch (p->state) {
case PROC_DYING: // someone else killed this already.
- spin_unlock_irqsave(&p->proc_lock);
- check_for_local_death(p); // IPI may be on it's way.
+ __proc_unlock_ipi_pending(p, self_ipi_pending);
return;
case PROC_RUNNABLE_M:
/* Need to reclaim any cores this proc might have, even though it's
// here's how to do it manually
if (current == p) {
lcr3(boot_cr3);
- proc_decref(p); // this decref is for the cr3
+ proc_decref(p, 1); // this decref is for the cr3
current = NULL;
}
#endif
panic("Weird state(0x%08x) in proc_destroy", p->state);
}
__proc_set_state(p, PROC_DYING);
+ /* this decref is for the process in general */
+ p->env_refcnt--; // TODO (REF)
+ //proc_decref(p, 1);
- /* TODO: (REF) dirty hack. decref currently uses a lock, but needs to use
- * CAS instead (another lock would be slightly less ghetto). but we need to
- * decref before releasing the lock, since that could enable interrupts,
- * which would have us receive the DEATH IPI if this was called locally by
- * the target process. */
- //proc_decref(p); // this decref is for the process in general
- p->env_refcnt--;
- size_t refcnt = p->env_refcnt; // need to copy this in so it's not reloaded
-
- /* After unlocking, we can receive a DEATH IPI and clean up */
- spin_unlock_irqsave(&p->proc_lock);
-
- // coupled with the refcnt-- above, from decref. if this happened,
- // proc_destroy was called "remotely", and with no one else refcnting
- if (!refcnt)
- __proc_free(p);
-
- /* if our core is part of process p, then check/wait for the death IPI. */
- check_for_local_death(p);
+ /* Unlock and possible decref and wait. A death IPI should be on its way,
+ * either from the RUNNING_S one, or from proc_take_cores with a __death.
+ * in general, interrupts should be on when you call proc_destroy locally,
+ * but currently aren't for all things (like traphandlers). */
+ __proc_unlock_ipi_pending(p, self_ipi_pending);
return;
}
return i;
}
-/* Helper function. Find the vcoreid for a given physical core id.
- * You better hold the lock before calling this. If we use some sort of
- * pcoremap, we can avoid this linear search. */
-static uint32_t get_vcoreid(struct proc *SAFE p, int32_t pcoreid)
+/* Helper function. Find the vcoreid for a given physical core id. If we use
+ * some sort of pcoremap, we can avoid this linear search. You better hold the
+ * lock before calling this. Returns -1 on failure. */
+static int32_t __get_vcoreid(int32_t *corelist, size_t num, int32_t pcoreid)
{
- uint32_t i;
- for (i = 0; i < MAX_NUM_CPUS; i++)
- if (p->vcoremap[i] == pcoreid)
+ int32_t i;
+ bool found = FALSE;
+ for (i = 0; i < num; i++)
+ if (corelist[i] == pcoreid) {
+ found = TRUE;
break;
- if (i + 1 >= MAX_NUM_CPUS)
- warn("At the end of the vcorelist. Might want to check that out.");
- return i;
+ }
+ if (found)
+ return i;
+ else
+ return -1;
+}
+
+/* Helper function. Just like the one above, but this one panics on failure.
+ * You better hold the lock before calling this. */
+static int32_t get_vcoreid(struct proc *SAFE p, int32_t pcoreid)
+{
+ int32_t vcoreid = __get_vcoreid(p->vcoremap, p->num_vcores, pcoreid);
+ assert(vcoreid != -1);
+ return vcoreid;
+}
+
+/* Use this when you are waiting for an IPI that you sent yourself. In most
+ * cases, interrupts should already be on (like after a spin_unlock_irqsave from
+ * process context), but aren't always, like in proc_destroy(). We might be
+ * able to remove the enable_irq in the future. Think about this (TODO).
+ *
+ * Note this means all non-proc management interrupt handlers must return (which
+ * they need to do anyway), so that we get back to this point. */
+static inline void __wait_for_ipi(const char *fnname)
+{
+ enable_irq();
+ udelay(1000000);
+ panic("Waiting too long on core %d for an IPI in %s()!", core_id(), fnname);
}
/* Yields the calling core. Must be called locally (not async) for now.
*
* - RES_CORES amt_wanted will be the amount running after taking away the
* yielder, unless there are none left, in which case it will be 1.
- */
+ *
+ * This does not return (abandon_core()), so it will eat your reference. */
void proc_yield(struct proc *SAFE p)
{
spin_lock_irqsave(&p->proc_lock);
panic("Weird state(0x%08x) in proc_yield", p->state);
}
spin_unlock_irqsave(&p->proc_lock);
- // clean up the core and idle. for mgmt cores, they will ultimately call
- // manager, which will call schedule(), which will repick the yielding proc.
+ proc_decref(p, 1);
+ /* Clean up the core and idle. For mgmt cores, they will ultimately call
+ * manager, which will call schedule() and will repick the yielding proc. */
abandon_core();
}
* The other way would be to have this function have the side effect of changing
* state, and finding another way to do the need_to_idle.
*
- * In the event of an error, corelist will include all the cores that were *NOT*
- * given to the process (cores that are still free). Practically, this will be
- * all of them, since it seems like an all or nothing deal right now.
+ * The returned bool signals whether or not a stack-crushing IPI will come in
+ * once you unlock after this function.
*
- * WARNING: You must hold the proc_lock before calling this!*/
-
-// zra: If corelist has *num elements, then it would be best if the value is
-// passed instead of a pointer to it. If in the future some way will be needed
-// to return the number of cores, then it might be best to use a separate
-// parameter for that.
-error_t __proc_give_cores(struct proc *SAFE p, uint32_t corelist[], size_t *num)
+ * WARNING: You must hold the proc_lock before calling this! */
+bool __proc_give_cores(struct proc *SAFE p, int32_t *corelist, size_t num)
{ TRUSTEDBLOCK
+ bool self_ipi_pending = FALSE;
uint32_t free_vcoreid = 0;
switch (p->state) {
case (PROC_RUNNABLE_S):
case (PROC_RUNNING_S):
panic("Don't give cores to a process in a *_S state!\n");
- return -EINVAL;
break;
case (PROC_DYING):
- // just FYI, for debugging
- printk("[kernel] attempted to give cores to a DYING process.\n");
- return -EFAIL;
+ panic("Attempted to give cores to a DYING process.\n");
break;
case (PROC_RUNNABLE_M):
// set up vcoremap. list should be empty, but could be called
assert(p->vcoremap[i]);
}
// add new items to the vcoremap
- for (int i = 0; i < *num; i++) {
+ for (int i = 0; i < num; i++) {
// find the next free slot, which should be the next one
free_vcoreid = get_free_vcoreid(p, free_vcoreid);
printd("setting vcore %d to pcore %d\n", free_vcoreid, corelist[i]);
}
break;
case (PROC_RUNNING_M):
- for (int i = 0; i < *num; i++) {
+ /* Up the refcnt, since num cores are going to start using this
+ * process and have it loaded in their 'current'. */
+ // TODO: (REF) use proc_incref once we have atomics
+ p->env_refcnt += num;
+ if (__get_vcoreid(corelist, num, core_id()) != -1)
+ self_ipi_pending = TRUE;
+ for (int i = 0; i < num; i++) {
free_vcoreid = get_free_vcoreid(p, free_vcoreid);
printd("setting vcore %d to pcore %d\n", free_vcoreid, corelist[i]);
p->vcoremap[free_vcoreid] = corelist[i];
p->num_vcores++;
- assert(corelist[i] != core_id()); // sanity
send_active_message(corelist[i], __startcore, p,
- (struct Trapframe *)0,
- (void*SNT)free_vcoreid);
+ (struct Trapframe *)0,
+ (void*SNT)free_vcoreid);
}
break;
default:
panic("Weird proc state %d in proc_give_cores()!\n", p->state);
}
- return ESUCCESS;
+ return self_ipi_pending;
}
/* Makes process p's coremap look like corelist (add, remove, etc). Caller
* any cores that are getting removed.
*
* Before implementing this, we should probably think about when this will be
- * used. Implies preempting for the message.
+ * used. Implies preempting for the message. The more that I think about this,
+ * the less I like it. For now, don't use this, and think hard before
+ * implementing it.
*
- * WARNING: You must hold the proc_lock before calling this!*/
-error_t __proc_set_allcores(struct proc *SAFE p, uint32_t corelist[],
- size_t *num, amr_t message,TV(a0t) arg0,
- TV(a1t) arg1, TV(a2t) arg2)
+ * WARNING: You must hold the proc_lock before calling this! */
+bool __proc_set_allcores(struct proc *SAFE p, int32_t *corelist,
+ size_t *num, amr_t message,TV(a0t) arg0,
+ TV(a1t) arg1, TV(a2t) arg2)
{
panic("Set all cores not implemented.\n");
}
-/* Takes from process p the num cores listed in corelist. In the event of an
- * error, corelist will contain the list of cores that are free, and num will
- * contain how many items are in corelist. This isn't implemented yet, but
- * might be necessary later. Or not, and we'll never do it.
+/* Takes from process p the num cores listed in corelist, using the given
+ * message for the active message (__death, __preempt, etc). Like the others
+ * in this function group, bool signals whether or not an IPI is pending.
*
- * WARNING: You must hold the proc_lock before calling this!*/
-error_t __proc_take_cores(struct proc *SAFE p, uint32_t corelist[],
- size_t *num, amr_t message, TV(a0t) arg0,
- TV(a1t) arg1, TV(a2t) arg2)
+ * WARNING: You must hold the proc_lock before calling this! */
+bool __proc_take_cores(struct proc *SAFE p, int32_t *corelist,
+ size_t num, amr_t message, TV(a0t) arg0,
+ TV(a1t) arg1, TV(a2t) arg2)
{ TRUSTEDBLOCK
uint32_t vcoreid;
+ bool self_ipi_pending = FALSE;
switch (p->state) {
case (PROC_RUNNABLE_M):
assert(!message);
panic("Weird state %d in proc_take_cores()!\n", p->state);
}
spin_lock(&idle_lock);
- assert((*num <= p->num_vcores) && (num_idlecores + *num <= num_cpus));
+ assert((num <= p->num_vcores) && (num_idlecores + num <= num_cpus));
spin_unlock(&idle_lock);
- for (int i = 0; i < *num; i++) {
+ for (int i = 0; i < num; i++) {
vcoreid = get_vcoreid(p, corelist[i]);
assert(p->vcoremap[vcoreid] == corelist[i]);
- if (message)
+ if (message) {
+ if (p->vcoremap[vcoreid] == core_id())
+ self_ipi_pending = TRUE;
send_active_message(corelist[i], message, arg0, arg1, arg2);
+ }
// give the pcore back to the idlecoremap
put_idle_core(corelist[i]);
p->vcoremap[vcoreid] = -1;
}
- p->num_vcores -= *num;
- p->resources[RES_CORES].amt_granted -= *num;
- return 0;
+ p->num_vcores -= num;
+ p->resources[RES_CORES].amt_granted -= num;
+ return self_ipi_pending;
}
/* Takes all cores from a process, which must be in an _M state. Cores are
* placed back in the idlecoremap. If there's a message, such as __death or
- * __preempt, it will be sent to the cores.
+ * __preempt, it will be sent to the cores. The bool signals whether or not an
+ * IPI is coming in once you unlock.
*
* WARNING: You must hold the proc_lock before calling this! */
-error_t __proc_take_allcores(struct proc *SAFE p, amr_t message,
- TV(a0t) arg0, TV(a1t) arg1, TV(a2t) arg2)
+bool __proc_take_allcores(struct proc *SAFE p, amr_t message,
+ TV(a0t) arg0, TV(a1t) arg1, TV(a2t) arg2)
{
uint32_t active_vcoreid = 0;
+ bool self_ipi_pending = FALSE;
switch (p->state) {
case (PROC_RUNNABLE_M):
assert(!message);
for (int i = 0; i < p->num_vcores; i++) {
// find next active vcore
active_vcoreid = get_busy_vcoreid(p, active_vcoreid);
- if (message)
+ if (message) {
+ if (p->vcoremap[active_vcoreid] == core_id())
+ self_ipi_pending = TRUE;
send_active_message(p->vcoremap[active_vcoreid], message,
arg0, arg1, arg2);
+ }
// give the pcore back to the idlecoremap
put_idle_core(p->vcoremap[active_vcoreid]);
p->vcoremap[active_vcoreid] = -1;
}
p->num_vcores = 0;
p->resources[RES_CORES].amt_granted = 0;
- return 0;
+ return self_ipi_pending;
}
-/*
- * The process refcnt is the number of places the process 'exists' in the
- * system. Creation counts as 1. Having your page tables loaded somewhere
- * (lcr3) counts as another 1. A non-RUNNING_* process should have refcnt at
- * least 1. If the kernel is on another core and in a processes address space
- * (like processing its backring), that counts as another 1.
- *
- * Note that the actual loading and unloading of cr3 is up to the caller, since
- * that's not the only use for this (and decoupling is more flexible).
- *
- * The refcnt should always be greater than 0 for processes that aren't dying.
- * When refcnt is 0, the process is dying and should not allow any more increfs.
- * A process can be dying with a refcnt greater than 0, since it could be
- * waiting for other cores to "get the message" to die, or a kernel core can be
- * finishing work in the processes's address space.
+/* Helper, to be used when unlocking after calling the above functions that
+ * might cause an IPI to be sent. TODO inline this, so the __FUNCTION__ works.
+ * Will require an overhaul of core_request (break it up, etc) */
+void __proc_unlock_ipi_pending(struct proc *p, bool ipi_pending)
+{
+ if (ipi_pending) {
+ p->env_refcnt--; // TODO: (REF) (atomics)
+ spin_unlock_irqsave(&p->proc_lock);
+ __wait_for_ipi(__FUNCTION__);
+ } else {
+ spin_unlock_irqsave(&p->proc_lock);
+ }
+}
+
+
+/* This takes a referenced process and ups the refcnt by count. If the refcnt
+ * was already 0, then someone has a bug, so panic. Check out the Documentation
+ * for brutal details about refcnting.
*
* Implementation aside, the important thing is that we atomically increment
- * only if it wasn't already 0. If it was 0, then we shouldn't be attaching to
- * the process, so we return an error, which should be handled however is
- * appropriate. We currently use spinlocks, but some sort of clever atomics
- * would work too.
+ * only if it wasn't already 0. If it was 0, panic.
*
- * Also, no one should ever update the refcnt outside of these functions.
- * Eventually, we'll have Ivy support for this. (TODO)
- *
- * TODO: (REF) change to use CAS.
- */
-error_t proc_incref(struct proc *p)
+ * TODO: (REF) change to use CAS / atomics. */
+void proc_incref(struct proc *p, size_t count)
{
- error_t retval = 0;
spin_lock_irqsave(&p->proc_lock);
if (p->env_refcnt)
- p->env_refcnt++;
+ p->env_refcnt += count;
else
- retval = -EBADPROC;
+ panic("Tried to incref a proc with no existing refernces!");
spin_unlock_irqsave(&p->proc_lock);
- return retval;
}
-/*
- * When the kernel is done with a process, it decrements its reference count.
- * When the count hits 0, no one is using it and it should be freed.
- * "Last one out" actually finalizes the death of the process. This is tightly
- * coupled with the previous function (incref)
- * Be sure to load a different cr3 before calling this!
+/* When the kernel is done with a process, it decrements its reference count.
+ * When the count hits 0, no one is using it and it should be freed. "Last one
+ * out" actually finalizes the death of the process. This is tightly coupled
+ * with the previous function (incref)
*
* TODO: (REF) change to use CAS. Note that when we do so, we may be holding
- * the process lock when calling __proc_free().
- */
-void proc_decref(struct proc *p)
+ * the process lock when calling __proc_free(). */
+void proc_decref(struct proc *p, size_t count)
{
spin_lock_irqsave(&p->proc_lock);
- p->env_refcnt--;
+ p->env_refcnt -= count;
size_t refcnt = p->env_refcnt; // need to copy this in so it's not reloaded
spin_unlock_irqsave(&p->proc_lock);
// if we hit 0, no one else will increment and we can check outside the lock
if (!refcnt)
__proc_free(p);
+ if (refcnt < 0)
+ panic("Too many decrefs!");
}
/* Active message handler to start a process's context on this core. Tightly
trapframe_t local_tf;
trapframe_t *tf_to_pop = (trapframe_t *CT(1))a1;
- printk("[kernel] Startcore on physical core %d\n", coreid);
+ printk("[kernel] Startcore on physical core %d for Process %d\n",
+ coreid, p_to_run->pid);
assert(p_to_run);
// TODO: handle silly state (HSS)
if (!tf_to_pop) {
tf_to_pop = &local_tf;
memset(tf_to_pop, 0, sizeof(*tf_to_pop));
- proc_init_trapframe(tf_to_pop);
+ proc_init_trapframe(tf_to_pop,(uint32_t)a2);
// Note the init_tf sets tf_to_pop->tf_esp = USTACKTOP;
- proc_set_tfcoreid(tf_to_pop, (uint32_t)a2);
proc_set_program_counter(tf_to_pop, p_to_run->env_entry);
}
+ /* the sender of the amsg increfed, thinking we weren't running current. */
+ if (p_to_run == current)
+ proc_decref(p_to_run, 1);
proc_startcore(p_to_run, tf_to_pop);
}
-/* Stop running whatever context is on this core and to 'idle'. Note this
- * leaves no trace of what was running. This "leaves the process's context. */
+/* Stop running whatever context is on this core, load a known-good cr3, and
+ * 'idle'. Note this leaves no trace of what was running. This "leaves the
+ * process's context. */
void abandon_core(void)
{
/* If we are currently running an address space on our core, we need a known
- * good pgdir before releasing the old one. This is currently the major
- * practical implication of the kernel caring about a processes existence
- * (the inc and decref). This decref corresponds to the incref in
- * proc_startcore (though it's not the only one). */
+ * good pgdir before releasing the old one. We decref, since current no
+ * longer tracks the proc (and current no longer protects the cr3). */
if (current) {
lcr3(boot_cr3);
- proc_decref(current);
+ proc_decref(current, 1);
set_current_proc(NULL);
}
smp_idle();
spin_lock(&pid_hash_lock);
if (hashtable_count(pid_hash)) {
hashtable_itr_t *phtable_i = hashtable_iterator(pid_hash);
+ printk("PID STATE \n");
+ printk("------------------\n");
do {
- printk("PID: %d\n", hashtable_iterator_key(phtable_i));
+ struct proc* p = hashtable_iterator_value(phtable_i);
+ printk("%8d %s\n", hashtable_iterator_key(phtable_i),p ? procstate2str(p->state) : "(null)");
} while (hashtable_iterator_advance(phtable_i));
}
spin_unlock(&pid_hash_lock);
printk("PID: %d\n", p->pid);
printk("PPID: %d\n", p->ppid);
printk("State: 0x%08x\n", p->state);
- printk("Refcnt: %d\n", p->env_refcnt);
+ printk("Refcnt: %d\n", p->env_refcnt - 1); // don't report our ref
printk("Flags: 0x%08x\n", p->env_flags);
printk("CR3(phys): 0x%08x\n", p->env_cr3);
printk("Num Vcores: %d\n", p->num_vcores);
printk("Vcore 0's Last Trapframe:\n");
print_trapframe(&p->env_tf);
spin_unlock_irqsave(&p->proc_lock);
+ proc_decref(p, 1); /* decref for the pid2proc reference */
}
projects / akaros.git / blobdiff