diff options
Diffstat (limited to 'arch/powerpc/platforms/cell/spufs/fault.c')
| -rw-r--r-- | arch/powerpc/platforms/cell/spufs/fault.c | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/cell/spufs/fault.c b/arch/powerpc/platforms/cell/spufs/fault.c new file mode 100644 index 00000000000..0f75c07e29d --- /dev/null +++ b/arch/powerpc/platforms/cell/spufs/fault.c @@ -0,0 +1,211 @@ +/* + * Low-level SPU handling + * + * (C) Copyright IBM Deutschland Entwicklung GmbH 2005 + * + * Author: Arnd Bergmann <arndb@de.ibm.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2, or (at your option) + * any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ +#include <linux/sched.h> +#include <linux/mm.h> +#include <linux/module.h> + +#include <asm/spu.h> +#include <asm/spu_csa.h> + +#include "spufs.h" + +/* + * This ought to be kept in sync with the powerpc specific do_page_fault + * function. Currently, there are a few corner cases that we haven't had + * to handle fortunately. + */ +static int spu_handle_mm_fault(struct mm_struct *mm, unsigned long ea, unsigned long dsisr) +{ + struct vm_area_struct *vma; + unsigned long is_write; + int ret; + +#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 (expand_stack(vma, ea)) + goto bad_area; +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; +} + +static void spufs_handle_dma_error(struct spu_context *ctx, + unsigned long ea, int type) +{ + if (ctx->flags & SPU_CREATE_EVENTS_ENABLED) { + ctx->event_return |= type; + wake_up_all(&ctx->stop_wq); + } else { + siginfo_t info; + memset(&info, 0, sizeof(info)); + + switch (type) { + case SPE_EVENT_INVALID_DMA: + info.si_signo = SIGBUS; + info.si_code = BUS_OBJERR; + break; + case SPE_EVENT_SPE_DATA_STORAGE: + info.si_signo = SIGBUS; + info.si_addr = (void __user *)ea; + info.si_code = BUS_ADRERR; + break; + case SPE_EVENT_DMA_ALIGNMENT: + info.si_signo = SIGBUS; + /* DAR isn't set for an alignment fault :( */ + info.si_code = BUS_ADRALN; + break; + case SPE_EVENT_SPE_ERROR: + info.si_signo = SIGILL; + info.si_addr = (void __user *)(unsigned long) + ctx->ops->npc_read(ctx) - 4; + info.si_code = ILL_ILLOPC; + break; + } + if (info.si_signo) + force_sig_info(info.si_signo, &info, current); + } +} + +void spufs_dma_callback(struct spu *spu, int type) +{ + spufs_handle_dma_error(spu->ctx, spu->dar, type); +} +EXPORT_SYMBOL_GPL(spufs_dma_callback); + +/* + * 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; + 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. + */ + if (ctx->state == SPU_STATE_RUNNABLE) { + ea = ctx->spu->dar; + dsisr = ctx->spu->dsisr; + ctx->spu->dar= ctx->spu->dsisr = 0; + } else { + ea = ctx->csa.priv1.mfc_dar_RW; + dsisr = ctx->csa.priv1.mfc_dsisr_RW; + ctx->csa.priv1.mfc_dar_RW = 0; + ctx->csa.priv1.mfc_dsisr_RW = 0; + } + + if (!(dsisr & (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED))) + return 0; + + pr_debug("ctx %p: ea %016lx, dsisr %016lx state %d\n", ctx, ea, + dsisr, ctx->state); + + /* 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); + + spu_acquire(ctx); + /* + * 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 (ctx->spu) + ctx->ops->restart_dma(ctx); + } else + spufs_handle_dma_error(ctx, ea, SPE_EVENT_SPE_DATA_STORAGE); + + return ret; +} +EXPORT_SYMBOL_GPL(spufs_handle_class1); |