diff options
Diffstat (limited to 'arch/powerpc/platforms/cell/spufs/fault.c')
| -rw-r--r-- | arch/powerpc/platforms/cell/spufs/fault.c | 191 |
1 files changed, 191 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 000000000..83cf58daa --- /dev/null +++ b/arch/powerpc/platforms/cell/spufs/fault.c @@ -0,0 +1,191 @@ +/* + * 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/signal.h> +#include <linux/mm.h> + +#include <asm/spu.h> +#include <asm/spu_csa.h> + +#include "spufs.h" + +/** + * Handle an SPE event, depending on context SPU_CREATE_EVENTS_ENABLED flag. + * + * If the context was created with events, we just set the return event. + * Otherwise, send an appropriate signal to the process. + */ +static void spufs_handle_event(struct spu_context *ctx, + unsigned long ea, int type) +{ + siginfo_t info; + + if (ctx->flags & SPU_CREATE_EVENTS_ENABLED) { + ctx->event_return |= type; + wake_up_all(&ctx->stop_wq); + return; + } + + clear_siginfo(&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 = SIGSEGV; + info.si_addr = (void __user *)ea; + info.si_code = SEGV_ACCERR; + ctx->ops->restart_dma(ctx); + 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); +} + +int spufs_handle_class0(struct spu_context *ctx) +{ + unsigned long stat = ctx->csa.class_0_pending & CLASS0_INTR_MASK; + + if (likely(!stat)) + return 0; + + if (stat & CLASS0_DMA_ALIGNMENT_INTR) + spufs_handle_event(ctx, ctx->csa.class_0_dar, + SPE_EVENT_DMA_ALIGNMENT); + + if (stat & CLASS0_INVALID_DMA_COMMAND_INTR) + spufs_handle_event(ctx, ctx->csa.class_0_dar, + SPE_EVENT_INVALID_DMA); + + if (stat & CLASS0_SPU_ERROR_INTR) + spufs_handle_event(ctx, ctx->csa.class_0_dar, + SPE_EVENT_SPE_ERROR); + + ctx->csa.class_0_pending = 0; + + return -EIO; +} + +/* + * 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; + vm_fault_t 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 copro_handle_mm_fault */ + spu_release(ctx); + + access = (_PAGE_PRESENT | _PAGE_READ); + access |= (dsisr & MFC_DSISR_ACCESS_PUT) ? _PAGE_WRITE : 0UL; + local_irq_save(flags); + ret = hash_page(ea, access, 0x300, dsisr); + local_irq_restore(flags); + + /* hashing failed, so try the actual fault handler */ + if (ret) + ret = copro_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; +} |