[POWERPC] spufs: make spu page faults not block scheduling

Until now, we have always entered the spu page fault handler
with a mutex for the spu context held. This has multiple
bad side-effects:
- it becomes impossible to suspend the context during
  page faults
- if an spu program attempts to access its own mmio
  areas through DMA, we get an immediate livelock when
  the nopage function tries to acquire the same mutex

This patch makes the page fault logic operate on a
struct spu_context instead of a struct spu, and moves it
from spu_base.c to a new file fault.c inside of spufs.

We now also need to copy the dar and dsisr contents
of the last fault into the saved context to have it
accessible in case we schedule out the context before
activating the page fault handler.

Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>

1 files changed, 0 insertions, 103 deletions

diff --git a/arch/powerpc/platforms/cell/spu_base.c b/arch/powerpc/platforms/cell/spu_base.c
index 6242f3c19f68..31fa55f33415 100644
--- a/arch/powerpc/platforms/cell/spu_base.c
+++ b/arch/powerpc/platforms/cell/spu_base.c
@@ -290,7 +290,6 @@ spu_irq_class_1(int irq, void *data)
 
 	return stat ? IRQ_HANDLED : IRQ_NONE;
 }
-EXPORT_SYMBOL_GPL(spu_irq_class_1_bottom);
 
 static irqreturn_t
 spu_irq_class_2(int irq, void *data)
@@ -462,108 +461,6 @@ void spu_free(struct spu *spu)
 }
 EXPORT_SYMBOL_GPL(spu_free);
 
-static int spu_handle_mm_fault(struct spu *spu)
-{
-	struct mm_struct *mm = spu->mm;
-	struct vm_area_struct *vma;
-	u64 ea, dsisr, is_write;
-	int ret;
-
-	ea = spu->dar;
-	dsisr = spu->dsisr;
-#if 0
-	if (!IS_VALID_EA(ea)) {
-		return -EFAULT;
-	}
-#endif /* XXX */
-	if (mm == NULL) {
-		return -EFAULT;
-	}
-	if (mm->pgd == NULL) {
-		return -EFAULT;
-	}
-
-	down_read(&mm->mmap_sem);
-	vma = find_vma(mm, ea);
-	if (!vma)
-		goto bad_area;
-	if (vma->vm_start <= ea)
-		goto good_area;
-	if (!(vma->vm_flags & VM_GROWSDOWN))
-		goto bad_area;
-#if 0
-	if (expand_stack(vma, ea))
-		goto bad_area;
-#endif /* XXX */
-good_area:
-	is_write = dsisr & MFC_DSISR_ACCESS_PUT;
-	if (is_write) {
-		if (!(vma->vm_flags & VM_WRITE))
-			goto bad_area;
-	} else {
-		if (dsisr & MFC_DSISR_ACCESS_DENIED)
-			goto bad_area;
-		if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
-			goto bad_area;
-	}
-	ret = 0;
-	switch (handle_mm_fault(mm, vma, ea, is_write)) {
-	case VM_FAULT_MINOR:
-		current->min_flt++;
-		break;
-	case VM_FAULT_MAJOR:
-		current->maj_flt++;
-		break;
-	case VM_FAULT_SIGBUS:
-		ret = -EFAULT;
-		goto bad_area;
-	case VM_FAULT_OOM:
-		ret = -ENOMEM;
-		goto bad_area;
-	default:
-		BUG();
-	}
-	up_read(&mm->mmap_sem);
-	return ret;
-
-bad_area:
-	up_read(&mm->mmap_sem);
-	return -EFAULT;
-}
-
-int spu_irq_class_1_bottom(struct spu *spu)
-{
-	u64 ea, dsisr, access, error = 0UL;
-	int ret = 0;
-
-	ea = spu->dar;
-	dsisr = spu->dsisr;
-	if (dsisr & (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED)) {
-		u64 flags;
-
-		access = (_PAGE_PRESENT | _PAGE_USER);
-		access |= (dsisr & MFC_DSISR_ACCESS_PUT) ? _PAGE_RW : 0UL;
-		local_irq_save(flags);
-		if (hash_page(ea, access, 0x300) != 0)
-			error |= CLASS1_ENABLE_STORAGE_FAULT_INTR;
-		local_irq_restore(flags);
-	}
-	if (error & CLASS1_ENABLE_STORAGE_FAULT_INTR) {
-		if ((ret = spu_handle_mm_fault(spu)) != 0)
-			error |= CLASS1_ENABLE_STORAGE_FAULT_INTR;
-		else
-			error &= ~CLASS1_ENABLE_STORAGE_FAULT_INTR;
-	}
-	spu->dar = 0UL;
-	spu->dsisr = 0UL;
-	if (!error) {
-		spu_restart_dma(spu);
-	} else {
-		spu->dma_callback(spu, SPE_EVENT_SPE_DATA_STORAGE);
-	}
-	return ret;
-}
-
 struct sysdev_class spu_sysdev_class = {
 	set_kset_name("spu")
 };