/**
* spu_acquire_exclusive - lock spu contex and protect against userspace access
* @ctx: spu contex to lock
*
* Note:
* Returns 0 and with the context locked on success
* Returns negative error and with the context _unlocked_ on failure.
*/
int spu_acquire_exclusive(struct spu_context *ctx)
{
int ret = -EINVAL;
spu_acquire(ctx);
/*
* Context is about to be freed, so we can't acquire it anymore.
*/
if (!ctx->owner)
goto out_unlock;
if (ctx->state == SPU_STATE_SAVED) {
ret = spu_activate(ctx, 0);
if (ret)
goto out_unlock;
} else {
/*
* We need to exclude userspace access to the context.
*
* To protect against memory access we invalidate all ptes
* and make sure the pagefault handlers block on the mutex.
*/
spu_unmap_mappings(ctx);
}
return 0;
out_unlock:
spu_release(ctx);
return ret;
}
int spufs_handle_class1(struct spu_context *ctx)
{
u64 ea, dsisr, access;
unsigned long flags;
unsigned flt = 0;
int ret;
ea = ctx->csa.class_1_dar;
dsisr = ctx->csa.class_1_dsisr;
if (!(dsisr & (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED)))
return 0;
spuctx_switch_state(ctx, SPU_UTIL_IOWAIT);
pr_debug("ctx %p: ea %016llx, dsisr %016llx state %d\n", ctx, ea,
dsisr, ctx->state);
ctx->stats.hash_flt++;
if (ctx->state == SPU_STATE_RUNNABLE)
ctx->spu->stats.hash_flt++;
spu_release(ctx);
access = (_PAGE_PRESENT | _PAGE_USER);
access |= (dsisr & MFC_DSISR_ACCESS_PUT) ? _PAGE_RW : 0UL;
local_irq_save(flags);
ret = hash_page(ea, access, 0x300);
local_irq_restore(flags);
if (ret)
ret = spu_handle_mm_fault(current->mm, ea, dsisr, &flt);
mutex_lock(&ctx->state_mutex);
ctx->csa.class_1_dar = ctx->csa.class_1_dsisr = 0;
if (!ret) {
if (flt & VM_FAULT_MAJOR)
ctx->stats.maj_flt++;
else
ctx->stats.min_flt++;
if (ctx->state == SPU_STATE_RUNNABLE) {
if (flt & VM_FAULT_MAJOR)
ctx->spu->stats.maj_flt++;
else
ctx->spu->stats.min_flt++;
}
if (ctx->spu)
ctx->ops->restart_dma(ctx);
} else
spufs_handle_event(ctx, ea, SPE_EVENT_SPE_DATA_STORAGE);
spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
return ret;
}
/* give up the mm reference when the context is about to be destroyed */
void spu_forget(struct spu_context *ctx)
{
struct mm_struct *mm;
spu_acquire_saved(ctx);
mm = ctx->owner;
ctx->owner = NULL;
mmput(mm);
spu_release(ctx);
}
/**
* spu_release_saved - unlock spu context and return it to the runqueue
* @ctx: context to unlock
*/
void spu_release_saved(struct spu_context *ctx)
{
BUG_ON(ctx->state != SPU_STATE_SAVED);
if (test_and_clear_bit(SPU_SCHED_WAS_ACTIVE, &ctx->sched_flags) &&
test_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags))
spu_activate(ctx, 0);
spu_release(ctx);
}
/* give up the mm reference when the context is about to be destroyed */
void spu_forget(struct spu_context *ctx)
{
struct mm_struct *mm;
/*
* This is basically an open-coded spu_acquire_saved, except that
* we don't acquire the state mutex interruptible, and we don't
* want this context to be rescheduled on release.
*/
mutex_lock(&ctx->state_mutex);
if (ctx->state != SPU_STATE_SAVED)
spu_deactivate(ctx);
mm = ctx->owner;
ctx->owner = NULL;
mmput(mm);
spu_release(ctx);
}
/**
* spu_acquire_runnable - lock spu contex and make sure it is in runnable state
* @ctx: spu contex to lock
*
* Note:
* Returns 0 and with the context locked on success
* Returns negative error and with the context _unlocked_ on failure.
*/
int spu_acquire_runnable(struct spu_context *ctx, unsigned long flags)
{
int ret = -EINVAL;
spu_acquire(ctx);
if (ctx->state == SPU_STATE_SAVED) {
/*
* Context is about to be freed, so we can't acquire it anymore.
*/
if (!ctx->owner)
goto out_unlock;
ret = spu_activate(ctx, flags);
if (ret)
goto out_unlock;
}
return 0;
out_unlock:
spu_release(ctx);
return ret;
}
/*
* bottom half handler for page faults, we can't do this from
* interrupt context, since we might need to sleep.
* we also need to give up the mutex so we can get scheduled
* out while waiting for the backing store.
*
* TODO: try calling hash_page from the interrupt handler first
* in order to speed up the easy case.
*/
int spufs_handle_class1(struct spu_context *ctx)
{
u64 ea, dsisr, access;
unsigned long flags;
unsigned flt = 0;
int ret;
/*
* dar and dsisr get passed from the registers
* to the spu_context, to this function, but not
* back to the spu if it gets scheduled again.
*
* if we don't handle the fault for a saved context
* in time, we can still expect to get the same fault
* the immediately after the context restore.
*/
ea = ctx->csa.class_1_dar;
dsisr = ctx->csa.class_1_dsisr;
if (!(dsisr & (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED)))
return 0;
spuctx_switch_state(ctx, SPU_UTIL_IOWAIT);
pr_debug("ctx %p: ea %016llx, dsisr %016llx state %d\n", ctx, ea,
dsisr, ctx->state);
ctx->stats.hash_flt++;
if (ctx->state == SPU_STATE_RUNNABLE)
ctx->spu->stats.hash_flt++;
/* we must not hold the lock when entering spu_handle_mm_fault */
spu_release(ctx);
access = (_PAGE_PRESENT | _PAGE_USER);
access |= (dsisr & MFC_DSISR_ACCESS_PUT) ? _PAGE_RW : 0UL;
local_irq_save(flags);
ret = hash_page(ea, access, 0x300);
local_irq_restore(flags);
/* hashing failed, so try the actual fault handler */
if (ret)
ret = spu_handle_mm_fault(current->mm, ea, dsisr, &flt);
/*
* This is nasty: we need the state_mutex for all the bookkeeping even
* if the syscall was interrupted by a signal. ewww.
*/
mutex_lock(&ctx->state_mutex);
/*
* Clear dsisr under ctxt lock after handling the fault, so that
* time slicing will not preempt the context while the page fault
* handler is running. Context switch code removes mappings.
*/
ctx->csa.class_1_dar = ctx->csa.class_1_dsisr = 0;
/*
* If we handled the fault successfully and are in runnable
* state, restart the DMA.
* In case of unhandled error report the problem to user space.
*/
if (!ret) {
if (flt & VM_FAULT_MAJOR)
ctx->stats.maj_flt++;
else
ctx->stats.min_flt++;
if (ctx->state == SPU_STATE_RUNNABLE) {
if (flt & VM_FAULT_MAJOR)
ctx->spu->stats.maj_flt++;
else
ctx->spu->stats.min_flt++;
}
if (ctx->spu)
ctx->ops->restart_dma(ctx);
} else
spufs_handle_event(ctx, ea, SPE_EVENT_SPE_DATA_STORAGE);
spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
return ret;
}
