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/*
* 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"
/**
* 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;
}
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 = 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.dar, SPE_EVENT_DMA_ALIGNMENT);
if (stat & CLASS0_INVALID_DMA_COMMAND_INTR)
spufs_handle_event(ctx, ctx->csa.dar, SPE_EVENT_INVALID_DMA);
if (stat & CLASS0_SPU_ERROR_INTR)
spufs_handle_event(ctx, ctx->csa.dar, SPE_EVENT_SPE_ERROR);
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;
unsigned flt = 0;
int ret, ret2;
/*
* 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.dar;
dsisr = ctx->csa.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 %016lx, dsisr %016lx 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);
/*
* If spu_acquire fails due to a pending signal we just want to return
* EINTR to userspace even if that means missing the dma restart or
* updating the page fault statistics.
*/
ret2 = spu_acquire(ctx);
if (ret2)
goto out;
/*
* 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.dar = ctx->csa.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);
out:
spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
return ret;
}
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