[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 = ctx->glpid = 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;

	/*
	 * take a ref on the afu so that it stays alive at-least till
	 * this context is reclaimed inside reclaim_ctx.
	 */
	cxl_afu_get(afu);
	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 */

	/* release the reference to the group leader and mm handling pid */
	put_pid(ctx->pid);
	put_pid(ctx->glpid);

	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);

	if (ctx->irq_bitmap)
		kfree(ctx->irq_bitmap);

	/* Drop ref to the afu device taken during cxl_context_init */
	cxl_afu_put(ctx->afu);

	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;
7b8ad495	45	ctx->pid = ctx->glpid = 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;
1b5df59e VJ	100
	101	/*
	102	* take a ref on the afu so that it stays alive at-least till
	103	* this context is reclaimed inside reclaim_ctx.
	104	*/
	105	cxl_afu_get(afu);
f204e0b8 IM	106	return 0;
	107	}
	108
0712dc7e IM	109	static int cxl_mmap_fault(struct vm_area_struct vma, struct vm_fault vmf)
	110	{
	111	struct cxl_context *ctx = vma->vm_file->private_data;
	112	unsigned long address = (unsigned long)vmf->virtual_address;
	113	u64 area, offset;
	114
	115	offset = vmf->pgoff << PAGE_SHIFT;
	116
	117	pr_devel("%s: pe: %i address: 0x%lx offset: 0x%llx\n",
	118	__func__, ctx->pe, address, offset);
	119
	120	if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
	121	area = ctx->afu->psn_phys;
10a5894f	122	if (offset >= ctx->afu->adapter->ps_size)
0712dc7e IM	123	return VM_FAULT_SIGBUS;
	124	} else {
	125	area = ctx->psn_phys;
10a5894f	126	if (offset >= ctx->psn_size)
0712dc7e IM	127	return VM_FAULT_SIGBUS;
	128	}
	129
	130	mutex_lock(&ctx->status_mutex);
	131
	132	if (ctx->status != STARTED) {
	133	mutex_unlock(&ctx->status_mutex);
	134	pr_devel("%s: Context not started, failing problem state access\n", __func__);
d9232a3d IM	135	if (ctx->mmio_err_ff) {
	136	if (!ctx->ff_page) {
	137	ctx->ff_page = alloc_page(GFP_USER);
	138	if (!ctx->ff_page)
	139	return VM_FAULT_OOM;
	140	memset(page_address(ctx->ff_page), 0xff, PAGE_SIZE);
	141	}
	142	get_page(ctx->ff_page);
	143	vmf->page = ctx->ff_page;
	144	vma->vm_page_prot = pgprot_cached(vma->vm_page_prot);
	145	return 0;
	146	}
0712dc7e IM	147	return VM_FAULT_SIGBUS;
	148	}
	149
	150	vm_insert_pfn(vma, address, (area + offset) >> PAGE_SHIFT);
	151
	152	mutex_unlock(&ctx->status_mutex);
	153
	154	return VM_FAULT_NOPAGE;
	155	}
	156
	157	static const struct vm_operations_struct cxl_mmap_vmops = {
	158	.fault = cxl_mmap_fault,
	159	};
	160
f204e0b8 IM	161	/*
	162	* Map a per-context mmio space into the given vma.
	163	*/
	164	int cxl_context_iomap(struct cxl_context ctx, struct vm_area_struct vma)
	165	{
5caaf534	166	u64 start = vma->vm_pgoff << PAGE_SHIFT;
f204e0b8	167	u64 len = vma->vm_end - vma->vm_start;
5caaf534 IM	168
	169	if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
	170	if (start + len > ctx->afu->adapter->ps_size)
	171	return -EINVAL;
	172	} else {
	173	if (start + len > ctx->psn_size)
	174	return -EINVAL;
	175	}
f204e0b8	176
0712dc7e IM	177	if (ctx->afu->current_mode != CXL_MODE_DEDICATED) {
	178	/* make sure there is a valid per process space for this AFU */
	179	if ((ctx->master && !ctx->afu->psa) \|\| (!ctx->afu->pp_psa)) {
	180	pr_devel("AFU doesn't support mmio space\n");
	181	return -EINVAL;
	182	}
f204e0b8	183
0712dc7e IM	184	/* Can't mmap until the AFU is enabled */
	185	if (!ctx->afu->enabled)
	186	return -EBUSY;
f204e0b8 IM	187	}
f204e0b8 IM	188
f204e0b8 IM	189	pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__,
	190	ctx->psn_phys, ctx->pe , ctx->master);
	191
0712dc7e	192	vma->vm_flags \|= VM_IO \| VM_PFNMAP;
f204e0b8	193	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
0712dc7e IM	194	vma->vm_ops = &cxl_mmap_vmops;
0712dc7e IM	195	return 0;
f204e0b8 IM	196	}
	197
	198	/*
	199	* Detach a context from the hardware. This disables interrupts and doesn't
	200	* return until all outstanding interrupts for this context have completed. The
	201	* hardware should no longer access *ctx after this has returned.
	202	*/
eda3693c	203	int __detach_context(struct cxl_context *ctx)
f204e0b8 IM	204	{
	205	enum cxl_context_status status;
	206
	207	mutex_lock(&ctx->status_mutex);
	208	status = ctx->status;
	209	ctx->status = CLOSED;
	210	mutex_unlock(&ctx->status_mutex);
	211	if (status != STARTED)
eda3693c	212	return -EBUSY;
f204e0b8	213
0b3f9c75 DA	214	/* Only warn if we detached while the link was OK.
	215	* If detach fails when hw is down, we don't care.
	216	*/
	217	WARN_ON(cxl_detach_process(ctx) &&
	218	cxl_adapter_link_ok(ctx->afu->adapter));
7bb5d91a	219	flush_work(&ctx->fault_work); /* Only needed for dedicated process */
7b8ad495 VJ	220
7b8ad495 VJ	221	/* release the reference to the group leader and mm handling pid */
7bb5d91a	222	put_pid(ctx->pid);
7b8ad495 VJ	223	put_pid(ctx->glpid);
7b8ad495 VJ	224
7bb5d91a	225	cxl_ctx_put();
eda3693c	226	return 0;
f204e0b8 IM	227	}
	228
	229	/*
	230	* Detach the given context from the AFU. This doesn't actually
	231	* free the context but it should stop the context running in hardware
	232	* (ie. prevent this context from generating any further interrupts
	233	* so that it can be freed).
	234	*/
	235	void cxl_context_detach(struct cxl_context *ctx)
	236	{
eda3693c MN	237	int rc;
	238
	239	rc = __detach_context(ctx);
	240	if (rc)
	241	return;
	242
	243	afu_release_irqs(ctx, ctx);
eda3693c	244	wake_up_all(&ctx->wq);
f204e0b8 IM	245	}
	246
	247	/*
	248	* Detach all contexts on the given AFU.
	249	*/
	250	void cxl_context_detach_all(struct cxl_afu *afu)
	251	{
	252	struct cxl_context *ctx;
	253	int tmp;
	254
ee41d11d IM	255	mutex_lock(&afu->contexts_lock);
ee41d11d IM	256	idr_for_each_entry(&afu->contexts_idr, ctx, tmp) {
f204e0b8 IM	257	/*
	258	* Anything done in here needs to be setup before the IDR is
	259	* created and torn down after the IDR removed
	260	*/
eda3693c	261	cxl_context_detach(ctx);
0712dc7e IM	262
	263	/*
	264	* We are force detaching - remove any active PSA mappings so
	265	* userspace cannot interfere with the card if it comes back.
	266	* Easiest way to exercise this is to unbind and rebind the
	267	* driver via sysfs while it is in use.
	268	*/
	269	mutex_lock(&ctx->mapping_lock);
	270	if (ctx->mapping)
	271	unmap_mapping_range(ctx->mapping, 0, 0, 1);
	272	mutex_unlock(&ctx->mapping_lock);
ee41d11d IM	273	}
ee41d11d IM	274	mutex_unlock(&afu->contexts_lock);
f204e0b8 IM	275	}
f204e0b8 IM	276
8ac75b96	277	static void reclaim_ctx(struct rcu_head *rcu)
f204e0b8	278	{
8ac75b96	279	struct cxl_context *ctx = container_of(rcu, struct cxl_context, rcu);
f204e0b8 IM	280
f204e0b8 IM	281	free_page((u64)ctx->sstp);
d9232a3d IM	282	if (ctx->ff_page)
d9232a3d IM	283	__free_page(ctx->ff_page);
f204e0b8	284	ctx->sstp = NULL;
55e07668 IM	285	if (ctx->kernelapi)
55e07668 IM	286	kfree(ctx->mapping);
f204e0b8	287
52adee58 AD	288	if (ctx->irq_bitmap)
	289	kfree(ctx->irq_bitmap);
	290
1b5df59e VJ	291	/* Drop ref to the afu device taken during cxl_context_init */
	292	cxl_afu_put(ctx->afu);
	293
f204e0b8 IM	294	kfree(ctx);
f204e0b8 IM	295	}
8ac75b96 IM	296
	297	void cxl_context_free(struct cxl_context *ctx)
	298	{
	299	mutex_lock(&ctx->afu->contexts_lock);
	300	idr_remove(&ctx->afu->contexts_idr, ctx->pe);
	301	mutex_unlock(&ctx->afu->contexts_lock);
	302	call_rcu(&ctx->rcu, reclaim_ctx);
	303	}