summaryrefslogtreecommitdiff
path: root/drivers/misc/ocxl/context.c
blob: 909e8807824a9c48bb2ef8b64705012f13e63e6d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
// SPDX-License-Identifier: GPL-2.0+
// Copyright 2017 IBM Corp.
#include <linux/sched/mm.h>
#include "trace.h"
#include "ocxl_internal.h"

struct ocxl_context *ocxl_context_alloc(void)
{
	return kzalloc(sizeof(struct ocxl_context), GFP_KERNEL);
}

int ocxl_context_init(struct ocxl_context *ctx, struct ocxl_afu *afu,
		struct address_space *mapping)
{
	int pasid;

	ctx->afu = afu;
	mutex_lock(&afu->contexts_lock);
	pasid = idr_alloc(&afu->contexts_idr, ctx, afu->pasid_base,
			afu->pasid_base + afu->pasid_max, GFP_KERNEL);
	if (pasid < 0) {
		mutex_unlock(&afu->contexts_lock);
		return pasid;
	}
	afu->pasid_count++;
	mutex_unlock(&afu->contexts_lock);

	ctx->pasid = pasid;
	ctx->status = OPENED;
	mutex_init(&ctx->status_mutex);
	ctx->mapping = mapping;
	mutex_init(&ctx->mapping_lock);
	init_waitqueue_head(&ctx->events_wq);
	mutex_init(&ctx->xsl_error_lock);
	mutex_init(&ctx->irq_lock);
	idr_init(&ctx->irq_idr);
	/*
	 * Keep a reference on the AFU to make sure it's valid for the
	 * duration of the life of the context
	 */
	ocxl_afu_get(afu);
	return 0;
}

/*
 * Callback for when a translation fault triggers an error
 * data:	a pointer to the context which triggered the fault
 * addr:	the address that triggered the error
 * dsisr:	the value of the PPC64 dsisr register
 */
static void xsl_fault_error(void *data, u64 addr, u64 dsisr)
{
	struct ocxl_context *ctx = (struct ocxl_context *) data;

	mutex_lock(&ctx->xsl_error_lock);
	ctx->xsl_error.addr = addr;
	ctx->xsl_error.dsisr = dsisr;
	ctx->xsl_error.count++;
	mutex_unlock(&ctx->xsl_error_lock);

	wake_up_all(&ctx->events_wq);
}

int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
{
	int rc;

	mutex_lock(&ctx->status_mutex);
	if (ctx->status != OPENED) {
		rc = -EIO;
		goto out;
	}

	rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid,
			current->mm->context.id, 0, amr, current->mm,
			xsl_fault_error, ctx);
	if (rc)
		goto out;

	ctx->status = ATTACHED;
out:
	mutex_unlock(&ctx->status_mutex);
	return rc;
}

static int map_afu_irq(struct vm_area_struct *vma, unsigned long address,
		u64 offset, struct ocxl_context *ctx)
{
	u64 trigger_addr;

	trigger_addr = ocxl_afu_irq_get_addr(ctx, offset);
	if (!trigger_addr)
		return VM_FAULT_SIGBUS;

	vm_insert_pfn(vma, address, trigger_addr >> PAGE_SHIFT);
	return VM_FAULT_NOPAGE;
}

static int map_pp_mmio(struct vm_area_struct *vma, unsigned long address,
		u64 offset, struct ocxl_context *ctx)
{
	u64 pp_mmio_addr;
	int pasid_off;

	if (offset >= ctx->afu->config.pp_mmio_stride)
		return VM_FAULT_SIGBUS;

	mutex_lock(&ctx->status_mutex);
	if (ctx->status != ATTACHED) {
		mutex_unlock(&ctx->status_mutex);
		pr_debug("%s: Context not attached, failing mmio mmap\n",
			__func__);
		return VM_FAULT_SIGBUS;
	}

	pasid_off = ctx->pasid - ctx->afu->pasid_base;
	pp_mmio_addr = ctx->afu->pp_mmio_start +
		pasid_off * ctx->afu->config.pp_mmio_stride +
		offset;

	vm_insert_pfn(vma, address, pp_mmio_addr >> PAGE_SHIFT);
	mutex_unlock(&ctx->status_mutex);
	return VM_FAULT_NOPAGE;
}

static int ocxl_mmap_fault(struct vm_fault *vmf)
{
	struct vm_area_struct *vma = vmf->vma;
	struct ocxl_context *ctx = vma->vm_file->private_data;
	u64 offset;
	int rc;

	offset = vmf->pgoff << PAGE_SHIFT;
	pr_debug("%s: pasid %d address 0x%lx offset 0x%llx\n", __func__,
		ctx->pasid, vmf->address, offset);

	if (offset < ctx->afu->irq_base_offset)
		rc = map_pp_mmio(vma, vmf->address, offset, ctx);
	else
		rc = map_afu_irq(vma, vmf->address, offset, ctx);
	return rc;
}

static const struct vm_operations_struct ocxl_vmops = {
	.fault = ocxl_mmap_fault,
};

static int check_mmap_afu_irq(struct ocxl_context *ctx,
			struct vm_area_struct *vma)
{
	/* only one page */
	if (vma_pages(vma) != 1)
		return -EINVAL;

	/* check offset validty */
	if (!ocxl_afu_irq_get_addr(ctx, vma->vm_pgoff << PAGE_SHIFT))
		return -EINVAL;

	/*
	 * trigger page should only be accessible in write mode.
	 *
	 * It's a bit theoretical, as a page mmaped with only
	 * PROT_WRITE is currently readable, but it doesn't hurt.
	 */
	if ((vma->vm_flags & VM_READ) || (vma->vm_flags & VM_EXEC) ||
		!(vma->vm_flags & VM_WRITE))
		return -EINVAL;
	vma->vm_flags &= ~(VM_MAYREAD | VM_MAYEXEC);
	return 0;
}

static int check_mmap_mmio(struct ocxl_context *ctx,
			struct vm_area_struct *vma)
{
	if ((vma_pages(vma) + vma->vm_pgoff) >
		(ctx->afu->config.pp_mmio_stride >> PAGE_SHIFT))
		return -EINVAL;
	return 0;
}

int ocxl_context_mmap(struct ocxl_context *ctx, struct vm_area_struct *vma)
{
	int rc;

	if ((vma->vm_pgoff << PAGE_SHIFT) < ctx->afu->irq_base_offset)
		rc = check_mmap_mmio(ctx, vma);
	else
		rc = check_mmap_afu_irq(ctx, vma);
	if (rc)
		return rc;

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

int ocxl_context_detach(struct ocxl_context *ctx)
{
	struct pci_dev *dev;
	int afu_control_pos;
	enum ocxl_context_status status;
	int rc;

	mutex_lock(&ctx->status_mutex);
	status = ctx->status;
	ctx->status = CLOSED;
	mutex_unlock(&ctx->status_mutex);
	if (status != ATTACHED)
		return 0;

	dev = to_pci_dev(ctx->afu->fn->dev.parent);
	afu_control_pos = ctx->afu->config.dvsec_afu_control_pos;

	mutex_lock(&ctx->afu->afu_control_lock);
	rc = ocxl_config_terminate_pasid(dev, afu_control_pos, ctx->pasid);
	mutex_unlock(&ctx->afu->afu_control_lock);
	trace_ocxl_terminate_pasid(ctx->pasid, rc);
	if (rc) {
		/*
		 * If we timeout waiting for the AFU to terminate the
		 * pasid, then it's dangerous to clean up the Process
		 * Element entry in the SPA, as it may be referenced
		 * in the future by the AFU. In which case, we would
		 * checkstop because of an invalid PE access (FIR
		 * register 2, bit 42). So leave the PE
		 * defined. Caller shouldn't free the context so that
		 * PASID remains allocated.
		 *
		 * A link reset will be required to cleanup the AFU
		 * and the SPA.
		 */
		if (rc == -EBUSY)
			return rc;
	}
	rc = ocxl_link_remove_pe(ctx->afu->fn->link, ctx->pasid);
	if (rc) {
		dev_warn(&ctx->afu->dev,
			"Couldn't remove PE entry cleanly: %d\n", rc);
	}
	return 0;
}

void ocxl_context_detach_all(struct ocxl_afu *afu)
{
	struct ocxl_context *ctx;
	int tmp;

	mutex_lock(&afu->contexts_lock);
	idr_for_each_entry(&afu->contexts_idr, ctx, tmp) {
		ocxl_context_detach(ctx);
		/*
		 * We are force detaching - remove any active mmio
		 * 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);
}

void ocxl_context_free(struct ocxl_context *ctx)
{
	mutex_lock(&ctx->afu->contexts_lock);
	ctx->afu->pasid_count--;
	idr_remove(&ctx->afu->contexts_idr, ctx->pasid);
	mutex_unlock(&ctx->afu->contexts_lock);

	ocxl_afu_irq_free_all(ctx);
	idr_destroy(&ctx->irq_idr);
	/* reference to the AFU taken in ocxl_context_init */
	ocxl_afu_put(ctx->afu);
	kfree(ctx);
}