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+/*
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+ * Low-level SPU handling
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+ *
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+ * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
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+ *
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+ * Author: Arnd Bergmann <arndb@de.ibm.com>
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+ *
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+ * This program is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License as published by
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+ * the Free Software Foundation; either version 2, or (at your option)
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+ * any later version.
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+ *
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+ * This program is distributed in the hope that it will be useful,
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+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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+ * GNU General Public License for more details.
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+ *
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+ * You should have received a copy of the GNU General Public License
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+ * along with this program; if not, write to the Free Software
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+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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+ */
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+#include <linux/sched.h>
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+#include <linux/mm.h>
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+#include <linux/module.h>
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+
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+#include <asm/spu.h>
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+#include <asm/spu_csa.h>
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+
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+#include "spufs.h"
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+
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+/*
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+ * This ought to be kept in sync with the powerpc specific do_page_fault
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+ * function. Currently, there are a few corner cases that we haven't had
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+ * to handle fortunately.
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+ */
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+static int spu_handle_mm_fault(struct mm_struct *mm, unsigned long ea, unsigned long dsisr)
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+{
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+ struct vm_area_struct *vma;
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+ unsigned long is_write;
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+ int ret;
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+
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+#if 0
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+ if (!IS_VALID_EA(ea)) {
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+ return -EFAULT;
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+ }
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+#endif /* XXX */
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+ if (mm == NULL) {
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+ return -EFAULT;
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+ }
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+ if (mm->pgd == NULL) {
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+ return -EFAULT;
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+ }
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+
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+ down_read(&mm->mmap_sem);
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+ vma = find_vma(mm, ea);
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+ if (!vma)
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+ goto bad_area;
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+ if (vma->vm_start <= ea)
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+ goto good_area;
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+ if (!(vma->vm_flags & VM_GROWSDOWN))
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+ goto bad_area;
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+ if (expand_stack(vma, ea))
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+ goto bad_area;
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+good_area:
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+ is_write = dsisr & MFC_DSISR_ACCESS_PUT;
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+ if (is_write) {
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+ if (!(vma->vm_flags & VM_WRITE))
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+ goto bad_area;
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+ } else {
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+ if (dsisr & MFC_DSISR_ACCESS_DENIED)
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+ goto bad_area;
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+ if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
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+ goto bad_area;
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+ }
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+ ret = 0;
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+ switch (handle_mm_fault(mm, vma, ea, is_write)) {
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+ case VM_FAULT_MINOR:
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+ current->min_flt++;
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+ break;
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+ case VM_FAULT_MAJOR:
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+ current->maj_flt++;
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+ break;
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+ case VM_FAULT_SIGBUS:
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+ ret = -EFAULT;
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+ goto bad_area;
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+ case VM_FAULT_OOM:
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+ ret = -ENOMEM;
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+ goto bad_area;
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+ default:
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+ BUG();
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+ }
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+ up_read(&mm->mmap_sem);
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+ return ret;
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+
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+bad_area:
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+ up_read(&mm->mmap_sem);
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+ return -EFAULT;
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+}
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+
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+static void spufs_handle_dma_error(struct spu_context *ctx, int type)
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+{
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+ if (ctx->flags & SPU_CREATE_EVENTS_ENABLED) {
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+ ctx->event_return |= type;
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+ wake_up_all(&ctx->stop_wq);
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+ } else {
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+ switch (type) {
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+ case SPE_EVENT_DMA_ALIGNMENT:
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+ case SPE_EVENT_SPE_DATA_STORAGE:
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+ case SPE_EVENT_INVALID_DMA:
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+ force_sig(SIGBUS, /* info, */ current);
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+ break;
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+ case SPE_EVENT_SPE_ERROR:
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+ force_sig(SIGILL, /* info */ current);
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+ break;
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+ }
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+ }
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+}
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+
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+void spufs_dma_callback(struct spu *spu, int type)
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+{
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+ spufs_handle_dma_error(spu->ctx, type);
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+}
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+EXPORT_SYMBOL_GPL(spufs_dma_callback);
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+
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+/*
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+ * bottom half handler for page faults, we can't do this from
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+ * interrupt context, since we might need to sleep.
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+ * we also need to give up the mutex so we can get scheduled
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+ * out while waiting for the backing store.
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+ *
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+ * TODO: try calling hash_page from the interrupt handler first
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+ * in order to speed up the easy case.
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+ */
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+int spufs_handle_class1(struct spu_context *ctx)
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+{
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+ u64 ea, dsisr, access;
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+ unsigned long flags;
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+ int ret;
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+
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+ /*
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+ * dar and dsisr get passed from the registers
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+ * to the spu_context, to this function, but not
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+ * back to the spu if it gets scheduled again.
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+ *
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+ * if we don't handle the fault for a saved context
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+ * in time, we can still expect to get the same fault
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+ * the immediately after the context restore.
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+ */
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+ if (ctx->state == SPU_STATE_RUNNABLE) {
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+ ea = ctx->spu->dar;
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+ dsisr = ctx->spu->dsisr;
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+ ctx->spu->dar= ctx->spu->dsisr = 0;
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+ } else {
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+ ea = ctx->csa.priv1.mfc_dar_RW;
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+ dsisr = ctx->csa.priv1.mfc_dsisr_RW;
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+ ctx->csa.priv1.mfc_dar_RW = 0;
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+ ctx->csa.priv1.mfc_dsisr_RW = 0;
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+ }
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+
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+ if (!(dsisr & (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED)))
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+ return 0;
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+
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+ pr_debug("ctx %p: ea %016lx, dsisr %016lx state %d\n", ctx, ea,
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+ dsisr, ctx->state);
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+
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+ /* we must not hold the lock when entering spu_handle_mm_fault */
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+ spu_release(ctx);
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+
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+ access = (_PAGE_PRESENT | _PAGE_USER);
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+ access |= (dsisr & MFC_DSISR_ACCESS_PUT) ? _PAGE_RW : 0UL;
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+ local_irq_save(flags);
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+ ret = hash_page(ea, access, 0x300);
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+ local_irq_restore(flags);
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+
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+ /* hashing failed, so try the actual fault handler */
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+ if (ret)
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+ ret = spu_handle_mm_fault(current->mm, ea, dsisr);
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+
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+ spu_acquire(ctx);
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+ /*
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+ * If we handled the fault successfully and are in runnable
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+ * state, restart the DMA.
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+ * In case of unhandled error report the problem to user space.
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+ */
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+ if (!ret) {
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+ if (ctx->spu)
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+ ctx->ops->restart_dma(ctx);
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+ } else
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+ spufs_handle_dma_error(ctx, SPE_EVENT_SPE_DATA_STORAGE);
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+
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+ return ret;
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+}
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+EXPORT_SYMBOL_GPL(spufs_handle_class1);
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Arnd Bergmann