[mirror_ubuntu-bionic-kernel.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)
{
	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 = NULL;

	/*
	 * 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;

	INIT_LIST_HEAD(&ctx->irq_names);
	INIT_LIST_HEAD(&ctx->extra_irq_contexts);

	/*
	 * 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, ctx->afu->adapter->min_pe,
		      ctx->afu->num_procs, GFP_NOWAIT);
	idr_preload_end();
	mutex_unlock(&afu->contexts_lock);
	if (i < 0)
		return i;

	ctx->pe = i;
	if (cpu_has_feature(CPU_FTR_HVMODE)) {
		ctx->elem = &ctx->afu->native->spa[i];
		ctx->external_pe = ctx->pe;
	} else {
		ctx->external_pe = -1; /* assigned when attaching */
	}
	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;
}

void cxl_context_set_mapping(struct cxl_context *ctx,
			struct address_space *mapping)
{
	mutex_lock(&ctx->mapping_lock);
	ctx->mapping = mapping;
	mutex_unlock(&ctx->mapping_lock);
}

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

	offset = vmf->pgoff << PAGE_SHIFT;

	pr_devel("%s: pe: %i address: 0x%lx offset: 0x%llx\n",
			__func__, ctx->pe, vmf->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, vmf->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_ops->detach_process(ctx) &&
		cxl_ops->link_ok(ctx->afu->adapter, ctx->afu));
	flush_work(&ctx->fault_work); /* Only needed for dedicated process */

	/*
	 * Wait until no further interrupts are presented by the PSL
	 * for this context.
	 */
	if (cxl_ops->irq_wait)
		cxl_ops->irq_wait(ctx);

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

	cxl_ctx_put();

	/* Decrease the attached context count on the adapter */
	cxl_adapter_context_put(ctx->afu->adapter);
	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;

	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)
{
	if (ctx->kernelapi && ctx->mapping)
		cxl_release_mapping(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	*/
bdecf76e	37	int cxl_context_init(struct cxl_context ctx, struct cxl_afu afu, bool master)
f204e0b8 IM	38	{
	39	int i;
	40
	41	spin_lock_init(&ctx->sste_lock);
	42	ctx->afu = afu;
	43	ctx->master = master;
7b8ad495	44	ctx->pid = ctx->glpid = NULL; /* Set in start work ioctl */
b123429e	45	mutex_init(&ctx->mapping_lock);
bdecf76e	46	ctx->mapping = NULL;
f204e0b8 IM	47
	48	/*
	49	* Allocate the segment table before we put it in the IDR so that we
	50	* can always access it when dereferenced from IDR. For the same
	51	* reason, the segment table is only destroyed after the context is
	52	* removed from the IDR. Access to this in the IOCTL is protected by
	53	* Linux filesytem symantics (can't IOCTL until open is complete).
	54	*/
	55	i = cxl_alloc_sst(ctx);
	56	if (i)
	57	return i;
	58
	59	INIT_WORK(&ctx->fault_work, cxl_handle_fault);
	60
	61	init_waitqueue_head(&ctx->wq);
	62	spin_lock_init(&ctx->lock);
	63
	64	ctx->irq_bitmap = NULL;
	65	ctx->pending_irq = false;
	66	ctx->pending_fault = false;
	67	ctx->pending_afu_err = false;
	68
f5c9df9a	69	INIT_LIST_HEAD(&ctx->irq_names);
cbce0917	70	INIT_LIST_HEAD(&ctx->extra_irq_contexts);
f5c9df9a	71
f204e0b8 IM	72	/*
	73	* When we have to destroy all contexts in cxl_context_detach_all() we
	74	* end up with afu_release_irqs() called from inside a
	75	* idr_for_each_entry(). Hence we need to make sure that anything
	76	* dereferenced from this IDR is ok before we allocate the IDR here.
	77	* This clears out the IRQ ranges to ensure this.
	78	*/
	79	for (i = 0; i < CXL_IRQ_RANGES; i++)
	80	ctx->irqs.range[i] = 0;
	81
	82	mutex_init(&ctx->status_mutex);
	83
	84	ctx->status = OPENED;
	85
	86	/*
	87	* Allocating IDR! We better make sure everything's setup that
	88	* dereferences from it.
	89	*/
ee41d11d	90	mutex_lock(&afu->contexts_lock);
f204e0b8	91	idr_preload(GFP_KERNEL);
16479337	92	i = idr_alloc(&ctx->afu->contexts_idr, ctx, ctx->afu->adapter->min_pe,
f204e0b8	93	ctx->afu->num_procs, GFP_NOWAIT);
f204e0b8	94	idr_preload_end();
ee41d11d	95	mutex_unlock(&afu->contexts_lock);
f204e0b8 IM	96	if (i < 0)
	97	return i;
	98
	99	ctx->pe = i;
14baf4d9	100	if (cpu_has_feature(CPU_FTR_HVMODE)) {
cbffa3a5	101	ctx->elem = &ctx->afu->native->spa[i];
14baf4d9 CL	102	ctx->external_pe = ctx->pe;
	103	} else {
	104	ctx->external_pe = -1; /* assigned when attaching */
	105	}
f204e0b8	106	ctx->pe_inserted = false;
1b5df59e VJ	107
	108	/*
	109	* take a ref on the afu so that it stays alive at-least till
	110	* this context is reclaimed inside reclaim_ctx.
	111	*/
	112	cxl_afu_get(afu);
f204e0b8 IM	113	return 0;
	114	}
	115
bdecf76e FB	116	void cxl_context_set_mapping(struct cxl_context *ctx,
	117	struct address_space *mapping)
	118	{
	119	mutex_lock(&ctx->mapping_lock);
	120	ctx->mapping = mapping;
	121	mutex_unlock(&ctx->mapping_lock);
	122	}
	123
0712dc7e IM	124	static int cxl_mmap_fault(struct vm_area_struct vma, struct vm_fault vmf)
	125	{
	126	struct cxl_context *ctx = vma->vm_file->private_data;
0712dc7e IM	127	u64 area, offset;
	128
	129	offset = vmf->pgoff << PAGE_SHIFT;
	130
	131	pr_devel("%s: pe: %i address: 0x%lx offset: 0x%llx\n",
1a29d85e	132	__func__, ctx->pe, vmf->address, offset);
0712dc7e IM	133
	134	if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
	135	area = ctx->afu->psn_phys;
10a5894f	136	if (offset >= ctx->afu->adapter->ps_size)
0712dc7e IM	137	return VM_FAULT_SIGBUS;
	138	} else {
	139	area = ctx->psn_phys;
10a5894f	140	if (offset >= ctx->psn_size)
0712dc7e IM	141	return VM_FAULT_SIGBUS;
	142	}
	143
	144	mutex_lock(&ctx->status_mutex);
	145
	146	if (ctx->status != STARTED) {
	147	mutex_unlock(&ctx->status_mutex);
	148	pr_devel("%s: Context not started, failing problem state access\n", __func__);
d9232a3d IM	149	if (ctx->mmio_err_ff) {
	150	if (!ctx->ff_page) {
	151	ctx->ff_page = alloc_page(GFP_USER);
	152	if (!ctx->ff_page)
	153	return VM_FAULT_OOM;
	154	memset(page_address(ctx->ff_page), 0xff, PAGE_SIZE);
	155	}
	156	get_page(ctx->ff_page);
	157	vmf->page = ctx->ff_page;
	158	vma->vm_page_prot = pgprot_cached(vma->vm_page_prot);
	159	return 0;
	160	}
0712dc7e IM	161	return VM_FAULT_SIGBUS;
	162	}
	163
1a29d85e	164	vm_insert_pfn(vma, vmf->address, (area + offset) >> PAGE_SHIFT);
0712dc7e IM	165
	166	mutex_unlock(&ctx->status_mutex);
	167
	168	return VM_FAULT_NOPAGE;
	169	}
	170
	171	static const struct vm_operations_struct cxl_mmap_vmops = {
	172	.fault = cxl_mmap_fault,
	173	};
	174
f204e0b8 IM	175	/*
	176	* Map a per-context mmio space into the given vma.
	177	*/
	178	int cxl_context_iomap(struct cxl_context ctx, struct vm_area_struct vma)
	179	{
5caaf534	180	u64 start = vma->vm_pgoff << PAGE_SHIFT;
f204e0b8	181	u64 len = vma->vm_end - vma->vm_start;
5caaf534 IM	182
	183	if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
	184	if (start + len > ctx->afu->adapter->ps_size)
	185	return -EINVAL;
	186	} else {
	187	if (start + len > ctx->psn_size)
	188	return -EINVAL;
	189	}
f204e0b8	190
0712dc7e IM	191	if (ctx->afu->current_mode != CXL_MODE_DEDICATED) {
	192	/* make sure there is a valid per process space for this AFU */
	193	if ((ctx->master && !ctx->afu->psa) \|\| (!ctx->afu->pp_psa)) {
	194	pr_devel("AFU doesn't support mmio space\n");
	195	return -EINVAL;
	196	}
f204e0b8	197
0712dc7e IM	198	/* Can't mmap until the AFU is enabled */
	199	if (!ctx->afu->enabled)
	200	return -EBUSY;
f204e0b8 IM	201	}
f204e0b8 IM	202
f204e0b8 IM	203	pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__,
	204	ctx->psn_phys, ctx->pe , ctx->master);
	205
0712dc7e	206	vma->vm_flags \|= VM_IO \| VM_PFNMAP;
f204e0b8	207	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
0712dc7e IM	208	vma->vm_ops = &cxl_mmap_vmops;
0712dc7e IM	209	return 0;
f204e0b8 IM	210	}
	211
	212	/*
	213	* Detach a context from the hardware. This disables interrupts and doesn't
	214	* return until all outstanding interrupts for this context have completed. The
	215	* hardware should no longer access *ctx after this has returned.
	216	*/
eda3693c	217	int __detach_context(struct cxl_context *ctx)
f204e0b8 IM	218	{
	219	enum cxl_context_status status;
	220
	221	mutex_lock(&ctx->status_mutex);
	222	status = ctx->status;
	223	ctx->status = CLOSED;
	224	mutex_unlock(&ctx->status_mutex);
	225	if (status != STARTED)
eda3693c	226	return -EBUSY;
f204e0b8	227
0b3f9c75 DA	228	/* Only warn if we detached while the link was OK.
	229	* If detach fails when hw is down, we don't care.
	230	*/
5be587b1	231	WARN_ON(cxl_ops->detach_process(ctx) &&
0d400f77	232	cxl_ops->link_ok(ctx->afu->adapter, ctx->afu));
7bb5d91a	233	flush_work(&ctx->fault_work); /* Only needed for dedicated process */
7b8ad495	234
2bc79ffc MN	235	/*
	236	* Wait until no further interrupts are presented by the PSL
	237	* for this context.
	238	*/
	239	if (cxl_ops->irq_wait)
	240	cxl_ops->irq_wait(ctx);
	241
7b8ad495	242	/* release the reference to the group leader and mm handling pid */
7bb5d91a	243	put_pid(ctx->pid);
7b8ad495 VJ	244	put_pid(ctx->glpid);
7b8ad495 VJ	245
7bb5d91a	246	cxl_ctx_put();
70b565bb VJ	247
	248	/* Decrease the attached context count on the adapter */
	249	cxl_adapter_context_put(ctx->afu->adapter);
eda3693c	250	return 0;
f204e0b8 IM	251	}
	252
	253	/*
	254	* Detach the given context from the AFU. This doesn't actually
	255	* free the context but it should stop the context running in hardware
	256	* (ie. prevent this context from generating any further interrupts
	257	* so that it can be freed).
	258	*/
	259	void cxl_context_detach(struct cxl_context *ctx)
	260	{
eda3693c MN	261	int rc;
	262
	263	rc = __detach_context(ctx);
	264	if (rc)
	265	return;
	266
	267	afu_release_irqs(ctx, ctx);
eda3693c	268	wake_up_all(&ctx->wq);
f204e0b8 IM	269	}
	270
	271	/*
	272	* Detach all contexts on the given AFU.
	273	*/
	274	void cxl_context_detach_all(struct cxl_afu *afu)
	275	{
	276	struct cxl_context *ctx;
	277	int tmp;
	278
ee41d11d IM	279	mutex_lock(&afu->contexts_lock);
ee41d11d IM	280	idr_for_each_entry(&afu->contexts_idr, ctx, tmp) {
f204e0b8 IM	281	/*
	282	* Anything done in here needs to be setup before the IDR is
	283	* created and torn down after the IDR removed
	284	*/
eda3693c	285	cxl_context_detach(ctx);
0712dc7e IM	286
	287	/*
	288	* We are force detaching - remove any active PSA mappings so
	289	* userspace cannot interfere with the card if it comes back.
	290	* Easiest way to exercise this is to unbind and rebind the
	291	* driver via sysfs while it is in use.
	292	*/
	293	mutex_lock(&ctx->mapping_lock);
	294	if (ctx->mapping)
	295	unmap_mapping_range(ctx->mapping, 0, 0, 1);
	296	mutex_unlock(&ctx->mapping_lock);
ee41d11d IM	297	}
ee41d11d IM	298	mutex_unlock(&afu->contexts_lock);
f204e0b8 IM	299	}
f204e0b8 IM	300
8ac75b96	301	static void reclaim_ctx(struct rcu_head *rcu)
f204e0b8	302	{
8ac75b96	303	struct cxl_context *ctx = container_of(rcu, struct cxl_context, rcu);
f204e0b8 IM	304
f204e0b8 IM	305	free_page((u64)ctx->sstp);
d9232a3d IM	306	if (ctx->ff_page)
d9232a3d IM	307	__free_page(ctx->ff_page);
f204e0b8 IM	308	ctx->sstp = NULL;
f204e0b8 IM	309
1050e689	310	kfree(ctx->irq_bitmap);
52adee58	311
1b5df59e VJ	312	/* Drop ref to the afu device taken during cxl_context_init */
	313	cxl_afu_put(ctx->afu);
	314
f204e0b8 IM	315	kfree(ctx);
f204e0b8 IM	316	}
8ac75b96 IM	317
	318	void cxl_context_free(struct cxl_context *ctx)
	319	{
bdecf76e FB	320	if (ctx->kernelapi && ctx->mapping)
bdecf76e FB	321	cxl_release_mapping(ctx);
8ac75b96 IM	322	mutex_lock(&ctx->afu->contexts_lock);
	323	idr_remove(&ctx->afu->contexts_idr, ctx->pe);
	324	mutex_unlock(&ctx->afu->contexts_lock);
	325	call_rcu(&ctx->rcu, reclaim_ctx);
	326	}