[deliverable/linux.git] / drivers / misc / cxl / context.c

/*
 * Copyright 2014 IBM Corp.
 *
 * 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 of the License, or (at your option) any later version.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/bitmap.h>
#include <linux/sched.h>
#include <linux/pid.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/debugfs.h>
#include <linux/slab.h>
#include <linux/idr.h>
#include <asm/cputable.h>
#include <asm/current.h>
#include <asm/copro.h>

#include "cxl.h"

/*
 * Allocates space for a CXL context.
 */
struct cxl_context *cxl_context_alloc(void)
{
	return kzalloc(sizeof(struct cxl_context), GFP_KERNEL);
}

/*
 * Initialises a CXL context.
 */
int cxl_context_init(struct cxl_context *ctx, struct cxl_afu *afu, bool master,
		     struct address_space *mapping)
{
	int i;

	spin_lock_init(&ctx->sste_lock);
	ctx->afu = afu;
	ctx->master = master;
	ctx->pid = NULL; /* Set in start work ioctl */
	mutex_init(&ctx->mapping_lock);
	ctx->mapping = mapping;

	/*
	 * Allocate the segment table before we put it in the IDR so that we
	 * can always access it when dereferenced from IDR. For the same
	 * reason, the segment table is only destroyed after the context is
	 * removed from the IDR.  Access to this in the IOCTL is protected by
	 * Linux filesytem symantics (can't IOCTL until open is complete).
	 */
	i = cxl_alloc_sst(ctx);
	if (i)
		return i;

	INIT_WORK(&ctx->fault_work, cxl_handle_fault);

	init_waitqueue_head(&ctx->wq);
	spin_lock_init(&ctx->lock);

	ctx->irq_bitmap = NULL;
	ctx->pending_irq = false;
	ctx->pending_fault = false;
	ctx->pending_afu_err = false;

	/*
	 * When we have to destroy all contexts in cxl_context_detach_all() we
	 * end up with afu_release_irqs() called from inside a
	 * idr_for_each_entry(). Hence we need to make sure that anything
	 * dereferenced from this IDR is ok before we allocate the IDR here.
	 * This clears out the IRQ ranges to ensure this.
	 */
	for (i = 0; i < CXL_IRQ_RANGES; i++)
		ctx->irqs.range[i] = 0;

	mutex_init(&ctx->status_mutex);

	ctx->status = OPENED;

	/*
	 * Allocating IDR! We better make sure everything's setup that
	 * dereferences from it.
	 */
	mutex_lock(&afu->contexts_lock);
	idr_preload(GFP_KERNEL);
	i = idr_alloc(&ctx->afu->contexts_idr, ctx, 0,
		      ctx->afu->num_procs, GFP_NOWAIT);
	idr_preload_end();
	mutex_unlock(&afu->contexts_lock);
	if (i < 0)
		return i;

	ctx->pe = i;
	ctx->elem = &ctx->afu->spa[i];
	ctx->pe_inserted = false;
	return 0;
}

static int cxl_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
	struct cxl_context *ctx = vma->vm_file->private_data;
	unsigned long address = (unsigned long)vmf->virtual_address;
	u64 area, offset;

	offset = vmf->pgoff << PAGE_SHIFT;

	pr_devel("%s: pe: %i address: 0x%lx offset: 0x%llx\n",
			__func__, ctx->pe, address, offset);

	if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
		area = ctx->afu->psn_phys;
		if (offset >= ctx->afu->adapter->ps_size)
			return VM_FAULT_SIGBUS;
	} else {
		area = ctx->psn_phys;
		if (offset >= ctx->psn_size)
			return VM_FAULT_SIGBUS;
	}

	mutex_lock(&ctx->status_mutex);

	if (ctx->status != STARTED) {
		mutex_unlock(&ctx->status_mutex);
		pr_devel("%s: Context not started, failing problem state access\n", __func__);
		if (ctx->mmio_err_ff) {
			if (!ctx->ff_page) {
				ctx->ff_page = alloc_page(GFP_USER);
				if (!ctx->ff_page)
					return VM_FAULT_OOM;
				memset(page_address(ctx->ff_page), 0xff, PAGE_SIZE);
			}
			get_page(ctx->ff_page);
			vmf->page = ctx->ff_page;
			vma->vm_page_prot = pgprot_cached(vma->vm_page_prot);
			return 0;
		}
		return VM_FAULT_SIGBUS;
	}

	vm_insert_pfn(vma, address, (area + offset) >> PAGE_SHIFT);

	mutex_unlock(&ctx->status_mutex);

	return VM_FAULT_NOPAGE;
}

static const struct vm_operations_struct cxl_mmap_vmops = {
	.fault = cxl_mmap_fault,
};

/*
 * Map a per-context mmio space into the given vma.
 */
int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma)
{
	u64 start = vma->vm_pgoff << PAGE_SHIFT;
	u64 len = vma->vm_end - vma->vm_start;

	if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
		if (start + len > ctx->afu->adapter->ps_size)
			return -EINVAL;
	} else {
		if (start + len > ctx->psn_size)
			return -EINVAL;
	}

	if (ctx->afu->current_mode != CXL_MODE_DEDICATED) {
		/* make sure there is a valid per process space for this AFU */
		if ((ctx->master && !ctx->afu->psa) || (!ctx->afu->pp_psa)) {
			pr_devel("AFU doesn't support mmio space\n");
			return -EINVAL;
		}

		/* Can't mmap until the AFU is enabled */
		if (!ctx->afu->enabled)
			return -EBUSY;
	}

	pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__,
		 ctx->psn_phys, ctx->pe , ctx->master);

	vma->vm_flags |= VM_IO | VM_PFNMAP;
	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
	vma->vm_ops = &cxl_mmap_vmops;
	return 0;
}

/*
 * Detach a context from the hardware. This disables interrupts and doesn't
 * return until all outstanding interrupts for this context have completed. The
 * hardware should no longer access *ctx after this has returned.
 */
int __detach_context(struct cxl_context *ctx)
{
	enum cxl_context_status status;

	mutex_lock(&ctx->status_mutex);
	status = ctx->status;
	ctx->status = CLOSED;
	mutex_unlock(&ctx->status_mutex);
	if (status != STARTED)
		return -EBUSY;

	/* Only warn if we detached while the link was OK.
	 * If detach fails when hw is down, we don't care.
	 */
	WARN_ON(cxl_detach_process(ctx) &&
		cxl_adapter_link_ok(ctx->afu->adapter));
	flush_work(&ctx->fault_work); /* Only needed for dedicated process */
	put_pid(ctx->pid);
	cxl_ctx_put();
	return 0;
}

/*
 * Detach the given context from the AFU. This doesn't actually
 * free the context but it should stop the context running in hardware
 * (ie. prevent this context from generating any further interrupts
 * so that it can be freed).
 */
void cxl_context_detach(struct cxl_context *ctx)
{
	int rc;

	rc = __detach_context(ctx);
	if (rc)
		return;

	afu_release_irqs(ctx, ctx);
	wake_up_all(&ctx->wq);
}

/*
 * Detach all contexts on the given AFU.
 */
void cxl_context_detach_all(struct cxl_afu *afu)
{
	struct cxl_context *ctx;
	int tmp;

	mutex_lock(&afu->contexts_lock);
	idr_for_each_entry(&afu->contexts_idr, ctx, tmp) {
		/*
		 * Anything done in here needs to be setup before the IDR is
		 * created and torn down after the IDR removed
		 */
		cxl_context_detach(ctx);

		/*
		 * We are force detaching - remove any active PSA mappings so
		 * userspace cannot interfere with the card if it comes back.
		 * Easiest way to exercise this is to unbind and rebind the
		 * driver via sysfs while it is in use.
		 */
		mutex_lock(&ctx->mapping_lock);
		if (ctx->mapping)
			unmap_mapping_range(ctx->mapping, 0, 0, 1);
		mutex_unlock(&ctx->mapping_lock);
	}
	mutex_unlock(&afu->contexts_lock);
}

static void reclaim_ctx(struct rcu_head *rcu)
{
	struct cxl_context *ctx = container_of(rcu, struct cxl_context, rcu);

	free_page((u64)ctx->sstp);
	if (ctx->ff_page)
		__free_page(ctx->ff_page);
	ctx->sstp = NULL;
	if (ctx->kernelapi)
		kfree(ctx->mapping);

	kfree(ctx);
}

void cxl_context_free(struct cxl_context *ctx)
{
	mutex_lock(&ctx->afu->contexts_lock);
	idr_remove(&ctx->afu->contexts_idr, ctx->pe);
	mutex_unlock(&ctx->afu->contexts_lock);
	call_rcu(&ctx->rcu, reclaim_ctx);
}
Commit	Line	Data
f204e0b8 IM	1	/*
	2	* Copyright 2014 IBM Corp.
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public License
	6	* as published by the Free Software Foundation; either version
	7	* 2 of the License, or (at your option) any later version.
	8	*/
	9
	10	#include <linux/module.h>
	11	#include <linux/kernel.h>
	12	#include <linux/bitmap.h>
	13	#include <linux/sched.h>
	14	#include <linux/pid.h>
	15	#include <linux/fs.h>
	16	#include <linux/mm.h>
	17	#include <linux/debugfs.h>
	18	#include <linux/slab.h>
	19	#include <linux/idr.h>
	20	#include <asm/cputable.h>
	21	#include <asm/current.h>
	22	#include <asm/copro.h>
	23
	24	#include "cxl.h"
	25
	26	/*
	27	* Allocates space for a CXL context.
	28	*/
	29	struct cxl_context *cxl_context_alloc(void)
	30	{
	31	return kzalloc(sizeof(struct cxl_context), GFP_KERNEL);
	32	}
	33
	34	/*
	35	* Initialises a CXL context.
	36	*/
b123429e IM	37	int cxl_context_init(struct cxl_context ctx, struct cxl_afu afu, bool master,
b123429e IM	38	struct address_space *mapping)
f204e0b8 IM	39	{
	40	int i;
	41
	42	spin_lock_init(&ctx->sste_lock);
	43	ctx->afu = afu;
	44	ctx->master = master;
	45	ctx->pid = NULL; /* Set in start work ioctl */
b123429e IM	46	mutex_init(&ctx->mapping_lock);
b123429e IM	47	ctx->mapping = mapping;
f204e0b8 IM	48
	49	/*
	50	* Allocate the segment table before we put it in the IDR so that we
	51	* can always access it when dereferenced from IDR. For the same
	52	* reason, the segment table is only destroyed after the context is
	53	* removed from the IDR. Access to this in the IOCTL is protected by
	54	* Linux filesytem symantics (can't IOCTL until open is complete).
	55	*/
	56	i = cxl_alloc_sst(ctx);
	57	if (i)
	58	return i;
	59
	60	INIT_WORK(&ctx->fault_work, cxl_handle_fault);
	61
	62	init_waitqueue_head(&ctx->wq);
	63	spin_lock_init(&ctx->lock);
	64
	65	ctx->irq_bitmap = NULL;
	66	ctx->pending_irq = false;
	67	ctx->pending_fault = false;
	68	ctx->pending_afu_err = false;
	69
	70	/*
	71	* When we have to destroy all contexts in cxl_context_detach_all() we
	72	* end up with afu_release_irqs() called from inside a
	73	* idr_for_each_entry(). Hence we need to make sure that anything
	74	* dereferenced from this IDR is ok before we allocate the IDR here.
	75	* This clears out the IRQ ranges to ensure this.
	76	*/
	77	for (i = 0; i < CXL_IRQ_RANGES; i++)
	78	ctx->irqs.range[i] = 0;
	79
	80	mutex_init(&ctx->status_mutex);
	81
	82	ctx->status = OPENED;
	83
	84	/*
	85	* Allocating IDR! We better make sure everything's setup that
	86	* dereferences from it.
	87	*/
ee41d11d	88	mutex_lock(&afu->contexts_lock);
f204e0b8	89	idr_preload(GFP_KERNEL);
f204e0b8 IM	90	i = idr_alloc(&ctx->afu->contexts_idr, ctx, 0,
f204e0b8 IM	91	ctx->afu->num_procs, GFP_NOWAIT);
f204e0b8	92	idr_preload_end();
ee41d11d	93	mutex_unlock(&afu->contexts_lock);
f204e0b8 IM	94	if (i < 0)
	95	return i;
	96
	97	ctx->pe = i;
	98	ctx->elem = &ctx->afu->spa[i];
	99	ctx->pe_inserted = false;
	100	return 0;
	101	}
	102
0712dc7e IM	103	static int cxl_mmap_fault(struct vm_area_struct vma, struct vm_fault vmf)
	104	{
	105	struct cxl_context *ctx = vma->vm_file->private_data;
	106	unsigned long address = (unsigned long)vmf->virtual_address;
	107	u64 area, offset;
	108
	109	offset = vmf->pgoff << PAGE_SHIFT;
	110
	111	pr_devel("%s: pe: %i address: 0x%lx offset: 0x%llx\n",
	112	__func__, ctx->pe, address, offset);
	113
	114	if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
	115	area = ctx->afu->psn_phys;
10a5894f	116	if (offset >= ctx->afu->adapter->ps_size)
0712dc7e IM	117	return VM_FAULT_SIGBUS;
	118	} else {
	119	area = ctx->psn_phys;
10a5894f	120	if (offset >= ctx->psn_size)
0712dc7e IM	121	return VM_FAULT_SIGBUS;
	122	}
	123
	124	mutex_lock(&ctx->status_mutex);
	125
	126	if (ctx->status != STARTED) {
	127	mutex_unlock(&ctx->status_mutex);
	128	pr_devel("%s: Context not started, failing problem state access\n", __func__);
d9232a3d IM	129	if (ctx->mmio_err_ff) {
	130	if (!ctx->ff_page) {
	131	ctx->ff_page = alloc_page(GFP_USER);
	132	if (!ctx->ff_page)
	133	return VM_FAULT_OOM;
	134	memset(page_address(ctx->ff_page), 0xff, PAGE_SIZE);
	135	}
	136	get_page(ctx->ff_page);
	137	vmf->page = ctx->ff_page;
	138	vma->vm_page_prot = pgprot_cached(vma->vm_page_prot);
	139	return 0;
	140	}
0712dc7e IM	141	return VM_FAULT_SIGBUS;
	142	}
	143
	144	vm_insert_pfn(vma, address, (area + offset) >> PAGE_SHIFT);
	145
	146	mutex_unlock(&ctx->status_mutex);
	147
	148	return VM_FAULT_NOPAGE;
	149	}
	150
	151	static const struct vm_operations_struct cxl_mmap_vmops = {
	152	.fault = cxl_mmap_fault,
	153	};
	154
f204e0b8 IM	155	/*
	156	* Map a per-context mmio space into the given vma.
	157	*/
	158	int cxl_context_iomap(struct cxl_context ctx, struct vm_area_struct vma)
	159	{
5caaf534	160	u64 start = vma->vm_pgoff << PAGE_SHIFT;
f204e0b8	161	u64 len = vma->vm_end - vma->vm_start;
5caaf534 IM	162
	163	if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
	164	if (start + len > ctx->afu->adapter->ps_size)
	165	return -EINVAL;
	166	} else {
	167	if (start + len > ctx->psn_size)
	168	return -EINVAL;
	169	}
f204e0b8	170
0712dc7e IM	171	if (ctx->afu->current_mode != CXL_MODE_DEDICATED) {
	172	/* make sure there is a valid per process space for this AFU */
	173	if ((ctx->master && !ctx->afu->psa) \|\| (!ctx->afu->pp_psa)) {
	174	pr_devel("AFU doesn't support mmio space\n");
	175	return -EINVAL;
	176	}
f204e0b8	177
0712dc7e IM	178	/* Can't mmap until the AFU is enabled */
	179	if (!ctx->afu->enabled)
	180	return -EBUSY;
f204e0b8 IM	181	}
f204e0b8 IM	182
f204e0b8 IM	183	pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__,
	184	ctx->psn_phys, ctx->pe , ctx->master);
	185
0712dc7e	186	vma->vm_flags \|= VM_IO \| VM_PFNMAP;
f204e0b8	187	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
0712dc7e IM	188	vma->vm_ops = &cxl_mmap_vmops;
0712dc7e IM	189	return 0;
f204e0b8 IM	190	}
	191
	192	/*
	193	* Detach a context from the hardware. This disables interrupts and doesn't
	194	* return until all outstanding interrupts for this context have completed. The
	195	* hardware should no longer access *ctx after this has returned.
	196	*/
eda3693c	197	int __detach_context(struct cxl_context *ctx)
f204e0b8 IM	198	{
	199	enum cxl_context_status status;
	200
	201	mutex_lock(&ctx->status_mutex);
	202	status = ctx->status;
	203	ctx->status = CLOSED;
	204	mutex_unlock(&ctx->status_mutex);
	205	if (status != STARTED)
eda3693c	206	return -EBUSY;
f204e0b8	207
0b3f9c75 DA	208	/* Only warn if we detached while the link was OK.
	209	* If detach fails when hw is down, we don't care.
	210	*/
	211	WARN_ON(cxl_detach_process(ctx) &&
	212	cxl_adapter_link_ok(ctx->afu->adapter));
7bb5d91a MN	213	flush_work(&ctx->fault_work); /* Only needed for dedicated process */
	214	put_pid(ctx->pid);
	215	cxl_ctx_put();
eda3693c	216	return 0;
f204e0b8 IM	217	}
	218
	219	/*
	220	* Detach the given context from the AFU. This doesn't actually
	221	* free the context but it should stop the context running in hardware
	222	* (ie. prevent this context from generating any further interrupts
	223	* so that it can be freed).
	224	*/
	225	void cxl_context_detach(struct cxl_context *ctx)
	226	{
eda3693c MN	227	int rc;
	228
	229	rc = __detach_context(ctx);
	230	if (rc)
	231	return;
	232
	233	afu_release_irqs(ctx, ctx);
eda3693c	234	wake_up_all(&ctx->wq);
f204e0b8 IM	235	}
	236
	237	/*
	238	* Detach all contexts on the given AFU.
	239	*/
	240	void cxl_context_detach_all(struct cxl_afu *afu)
	241	{
	242	struct cxl_context *ctx;
	243	int tmp;
	244
ee41d11d IM	245	mutex_lock(&afu->contexts_lock);
ee41d11d IM	246	idr_for_each_entry(&afu->contexts_idr, ctx, tmp) {
f204e0b8 IM	247	/*
	248	* Anything done in here needs to be setup before the IDR is
	249	* created and torn down after the IDR removed
	250	*/
eda3693c	251	cxl_context_detach(ctx);
0712dc7e IM	252
	253	/*
	254	* We are force detaching - remove any active PSA mappings so
	255	* userspace cannot interfere with the card if it comes back.
	256	* Easiest way to exercise this is to unbind and rebind the
	257	* driver via sysfs while it is in use.
	258	*/
	259	mutex_lock(&ctx->mapping_lock);
	260	if (ctx->mapping)
	261	unmap_mapping_range(ctx->mapping, 0, 0, 1);
	262	mutex_unlock(&ctx->mapping_lock);
ee41d11d IM	263	}
ee41d11d IM	264	mutex_unlock(&afu->contexts_lock);
f204e0b8 IM	265	}
f204e0b8 IM	266
8ac75b96	267	static void reclaim_ctx(struct rcu_head *rcu)
f204e0b8	268	{
8ac75b96	269	struct cxl_context *ctx = container_of(rcu, struct cxl_context, rcu);
f204e0b8 IM	270
f204e0b8 IM	271	free_page((u64)ctx->sstp);
d9232a3d IM	272	if (ctx->ff_page)
d9232a3d IM	273	__free_page(ctx->ff_page);
f204e0b8	274	ctx->sstp = NULL;
55e07668 IM	275	if (ctx->kernelapi)
55e07668 IM	276	kfree(ctx->mapping);
f204e0b8	277
f204e0b8 IM	278	kfree(ctx);
f204e0b8 IM	279	}
8ac75b96 IM	280
	281	void cxl_context_free(struct cxl_context *ctx)
	282	{
	283	mutex_lock(&ctx->afu->contexts_lock);
	284	idr_remove(&ctx->afu->contexts_idr, ctx->pe);
	285	mutex_unlock(&ctx->afu->contexts_lock);
	286	call_rcu(&ctx->rcu, reclaim_ctx);
	287	}