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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"
/*
* 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, unsigned *flt)
{
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;
*flt = handle_mm_fault(mm, vma, ea, is_write);
if (unlikely(*flt & VM_FAULT_ERROR)) {
if (*flt & VM_FAULT_OOM) {
ret = -ENOMEM;
goto bad_area;
} else if (*flt & VM_FAULT_SIGBUS) {
ret = -EFAULT;
goto bad_area;
}
BUG();
}
if (*flt & VM_FAULT_MAJOR)
current->maj_flt++;
else
current->min_flt++;
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;
unsigned 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.
*/
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;
spuctx_switch_state(ctx, SPUCTX_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++;
spu_switch_state(ctx->spu, SPU_UTIL_IOWAIT);
}
/* 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);
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 (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_dma_error(ctx, ea, SPE_EVENT_SPE_DATA_STORAGE);
spuctx_switch_state(ctx, SPUCTX_UTIL_SYSTEM);
return ret;
}
EXPORT_SYMBOL_GPL(spufs_handle_class1);
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