[mirror_ubuntu-zesty-kernel.git] / arch / powerpc / platforms / cell / spufs / fault.c

/*
 * 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;
	fault = handle_mm_fault(mm, vma, ea, is_write);
	if (unlikely(fault & VM_FAULT_ERROR)) {
		if (fault & VM_FAULT_OOM) {
			ret = -ENOMEM;
			goto bad_area;
		} else if (fault & VM_FAULT_SIGBUS) {
			ret = -EFAULT;
			goto bad_area;
		}
		BUG();
	}
	if (fault & 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_MINOR)
			ctx->stats.min_flt++;
		else
			ctx->stats.maj_flt++;
		if (ctx->state == SPU_STATE_RUNNABLE) {
			if (flt == VM_FAULT_MINOR)
				ctx->spu->stats.min_flt++;
			else
				ctx->spu->stats.maj_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);
Commit	Line	Data
57dace23 AB	1	/*
	2	* Low-level SPU handling
	3	*
	4	* (C) Copyright IBM Deutschland Entwicklung GmbH 2005
	5	*
	6	* Author: Arnd Bergmann <arndb@de.ibm.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License as published by
	10	* the Free Software Foundation; either version 2, or (at your option)
	11	* any later version.
	12	*
	13	* This program is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	* GNU General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU General Public License
	19	* along with this program; if not, write to the Free Software
	20	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	21	*/
	22	#include <linux/sched.h>
	23	#include <linux/mm.h>
	24	#include <linux/module.h>
	25
	26	#include <asm/spu.h>
	27	#include <asm/spu_csa.h>
	28
	29	#include "spufs.h"
	30
	31	/*
	32	* This ought to be kept in sync with the powerpc specific do_page_fault
	33	* function. Currently, there are a few corner cases that we haven't had
	34	* to handle fortunately.
	35	*/
e9f8a0b6 CH	36	static int spu_handle_mm_fault(struct mm_struct *mm, unsigned long ea,
e9f8a0b6 CH	37	unsigned long dsisr, unsigned *flt)
57dace23 AB	38	{
	39	struct vm_area_struct *vma;
	40	unsigned long is_write;
	41	int ret;
	42
	43	#if 0
	44	if (!IS_VALID_EA(ea)) {
	45	return -EFAULT;
	46	}
	47	#endif /* XXX */
	48	if (mm == NULL) {
	49	return -EFAULT;
	50	}
	51	if (mm->pgd == NULL) {
	52	return -EFAULT;
	53	}
	54
	55	down_read(&mm->mmap_sem);
	56	vma = find_vma(mm, ea);
	57	if (!vma)
	58	goto bad_area;
	59	if (vma->vm_start <= ea)
	60	goto good_area;
	61	if (!(vma->vm_flags & VM_GROWSDOWN))
	62	goto bad_area;
	63	if (expand_stack(vma, ea))
	64	goto bad_area;
	65	good_area:
	66	is_write = dsisr & MFC_DSISR_ACCESS_PUT;
	67	if (is_write) {
	68	if (!(vma->vm_flags & VM_WRITE))
	69	goto bad_area;
	70	} else {
	71	if (dsisr & MFC_DSISR_ACCESS_DENIED)
	72	goto bad_area;
	73	if (!(vma->vm_flags & (VM_READ \| VM_EXEC)))
	74	goto bad_area;
	75	}
	76	ret = 0;
83c54070 NP	77	fault = handle_mm_fault(mm, vma, ea, is_write);
	78	if (unlikely(fault & VM_FAULT_ERROR)) {
	79	if (fault & VM_FAULT_OOM) {
	80	ret = -ENOMEM;
	81	goto bad_area;
	82	} else if (fault & VM_FAULT_SIGBUS) {
	83	ret = -EFAULT;
	84	goto bad_area;
	85	}
57dace23 AB	86	BUG();
57dace23 AB	87	}
83c54070 NP	88	if (fault & VM_FAULT_MAJOR)
	89	current->maj_flt++;
	90	else
	91	current->min_flt++;
57dace23 AB	92	up_read(&mm->mmap_sem);
	93	return ret;
	94
	95	bad_area:
	96	up_read(&mm->mmap_sem);
	97	return -EFAULT;
	98	}
	99
c8a1e939 JK	100	static void spufs_handle_dma_error(struct spu_context *ctx,
c8a1e939 JK	101	unsigned long ea, int type)
57dace23 AB	102	{
	103	if (ctx->flags & SPU_CREATE_EVENTS_ENABLED) {
	104	ctx->event_return \|= type;
	105	wake_up_all(&ctx->stop_wq);
	106	} else {
c8a1e939 JK	107	siginfo_t info;
	108	memset(&info, 0, sizeof(info));
	109
57dace23	110	switch (type) {
57dace23	111	case SPE_EVENT_INVALID_DMA:
c8a1e939 JK	112	info.si_signo = SIGBUS;
	113	info.si_code = BUS_OBJERR;
	114	break;
	115	case SPE_EVENT_SPE_DATA_STORAGE:
	116	info.si_signo = SIGBUS;
	117	info.si_addr = (void __user *)ea;
	118	info.si_code = BUS_ADRERR;
	119	break;
	120	case SPE_EVENT_DMA_ALIGNMENT:
	121	info.si_signo = SIGBUS;
	122	/* DAR isn't set for an alignment fault :( */
	123	info.si_code = BUS_ADRALN;
57dace23 AB	124	break;
57dace23 AB	125	case SPE_EVENT_SPE_ERROR:
c8a1e939 JK	126	info.si_signo = SIGILL;
	127	info.si_addr = (void __user *)(unsigned long)
	128	ctx->ops->npc_read(ctx) - 4;
	129	info.si_code = ILL_ILLOPC;
57dace23 AB	130	break;
57dace23 AB	131	}
c8a1e939 JK	132	if (info.si_signo)
c8a1e939 JK	133	force_sig_info(info.si_signo, &info, current);
57dace23 AB	134	}
	135	}
	136
	137	void spufs_dma_callback(struct spu *spu, int type)
	138	{
c8a1e939	139	spufs_handle_dma_error(spu->ctx, spu->dar, type);
57dace23 AB	140	}
	141	EXPORT_SYMBOL_GPL(spufs_dma_callback);
	142
	143	/*
	144	* bottom half handler for page faults, we can't do this from
	145	* interrupt context, since we might need to sleep.
	146	* we also need to give up the mutex so we can get scheduled
	147	* out while waiting for the backing store.
	148	*
	149	* TODO: try calling hash_page from the interrupt handler first
	150	* in order to speed up the easy case.
	151	*/
	152	int spufs_handle_class1(struct spu_context *ctx)
	153	{
	154	u64 ea, dsisr, access;
	155	unsigned long flags;
e9f8a0b6	156	unsigned flt = 0;
57dace23 AB	157	int ret;
	158
	159	/*
	160	* dar and dsisr get passed from the registers
	161	* to the spu_context, to this function, but not
	162	* back to the spu if it gets scheduled again.
	163	*
	164	* if we don't handle the fault for a saved context
	165	* in time, we can still expect to get the same fault
	166	* the immediately after the context restore.
	167	*/
	168	if (ctx->state == SPU_STATE_RUNNABLE) {
	169	ea = ctx->spu->dar;
	170	dsisr = ctx->spu->dsisr;
	171	ctx->spu->dar= ctx->spu->dsisr = 0;
	172	} else {
	173	ea = ctx->csa.priv1.mfc_dar_RW;
	174	dsisr = ctx->csa.priv1.mfc_dsisr_RW;
	175	ctx->csa.priv1.mfc_dar_RW = 0;
	176	ctx->csa.priv1.mfc_dsisr_RW = 0;
	177	}
	178
	179	if (!(dsisr & (MFC_DSISR_PTE_NOT_FOUND \| MFC_DSISR_ACCESS_DENIED)))
	180	return 0;
	181
e9f8a0b6 CH	182	spuctx_switch_state(ctx, SPUCTX_UTIL_IOWAIT);
e9f8a0b6 CH	183
57dace23 AB	184	pr_debug("ctx %p: ea %016lx, dsisr %016lx state %d\n", ctx, ea,
	185	dsisr, ctx->state);
	186
e9f8a0b6	187	ctx->stats.hash_flt++;
fe2f896d CH	188	if (ctx->state == SPU_STATE_RUNNABLE) {
	189	ctx->spu->stats.hash_flt++;
	190	spu_switch_state(ctx->spu, SPU_UTIL_IOWAIT);
	191	}
e9f8a0b6	192
57dace23 AB	193	/* we must not hold the lock when entering spu_handle_mm_fault */
	194	spu_release(ctx);
	195
	196	access = (_PAGE_PRESENT \| _PAGE_USER);
	197	access \|= (dsisr & MFC_DSISR_ACCESS_PUT) ? _PAGE_RW : 0UL;
	198	local_irq_save(flags);
	199	ret = hash_page(ea, access, 0x300);
	200	local_irq_restore(flags);
	201
	202	/* hashing failed, so try the actual fault handler */
	203	if (ret)
e9f8a0b6	204	ret = spu_handle_mm_fault(current->mm, ea, dsisr, &flt);
57dace23 AB	205
	206	spu_acquire(ctx);
	207	/*
	208	* If we handled the fault successfully and are in runnable
	209	* state, restart the DMA.
	210	* In case of unhandled error report the problem to user space.
	211	*/
	212	if (!ret) {
e9f8a0b6 CH	213	if (flt == VM_FAULT_MINOR)
	214	ctx->stats.min_flt++;
	215	else
	216	ctx->stats.maj_flt++;
fe2f896d CH	217	if (ctx->state == SPU_STATE_RUNNABLE) {
	218	if (flt == VM_FAULT_MINOR)
	219	ctx->spu->stats.min_flt++;
	220	else
	221	ctx->spu->stats.maj_flt++;
	222	}
e9f8a0b6	223
57dace23 AB	224	if (ctx->spu)
	225	ctx->ops->restart_dma(ctx);
	226	} else
c8a1e939	227	spufs_handle_dma_error(ctx, ea, SPE_EVENT_SPE_DATA_STORAGE);
57dace23	228
e9f8a0b6	229	spuctx_switch_state(ctx, SPUCTX_UTIL_SYSTEM);
57dace23 AB	230	return ret;
	231	}
	232	EXPORT_SYMBOL_GPL(spufs_handle_class1);