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Note: File does not exist in v3.1.
  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 */
 29struct 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 */
 37int cxl_context_init(struct cxl_context *ctx, struct cxl_afu *afu, bool master,
 38		     struct address_space *mapping)
 39{
 40	int i;
 41
 42	spin_lock_init(&ctx->sste_lock);
 43	ctx->afu = afu;
 44	ctx->master = master;
 45	ctx->pid = ctx->glpid = NULL; /* Set in start work ioctl */
 46	mutex_init(&ctx->mapping_lock);
 47	ctx->mapping = mapping;
 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	 */
 88	mutex_lock(&afu->contexts_lock);
 89	idr_preload(GFP_KERNEL);
 90	i = idr_alloc(&ctx->afu->contexts_idr, ctx, 0,
 91		      ctx->afu->num_procs, GFP_NOWAIT);
 92	idr_preload_end();
 93	mutex_unlock(&afu->contexts_lock);
 94	if (i < 0)
 95		return i;
 96
 97	ctx->pe = i;
 98	if (cpu_has_feature(CPU_FTR_HVMODE)) {
 99		ctx->elem = &ctx->afu->native->spa[i];
100		ctx->external_pe = ctx->pe;
101	} else {
102		ctx->external_pe = -1; /* assigned when attaching */
103	}
104	ctx->pe_inserted = false;
105
106	/*
107	 * take a ref on the afu so that it stays alive at-least till
108	 * this context is reclaimed inside reclaim_ctx.
109	 */
110	cxl_afu_get(afu);
111	return 0;
112}
113
114static int cxl_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
115{
116	struct cxl_context *ctx = vma->vm_file->private_data;
117	unsigned long address = (unsigned long)vmf->virtual_address;
118	u64 area, offset;
119
120	offset = vmf->pgoff << PAGE_SHIFT;
121
122	pr_devel("%s: pe: %i address: 0x%lx offset: 0x%llx\n",
123			__func__, ctx->pe, address, offset);
124
125	if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
126		area = ctx->afu->psn_phys;
127		if (offset >= ctx->afu->adapter->ps_size)
128			return VM_FAULT_SIGBUS;
129	} else {
130		area = ctx->psn_phys;
131		if (offset >= ctx->psn_size)
132			return VM_FAULT_SIGBUS;
133	}
134
135	mutex_lock(&ctx->status_mutex);
136
137	if (ctx->status != STARTED) {
138		mutex_unlock(&ctx->status_mutex);
139		pr_devel("%s: Context not started, failing problem state access\n", __func__);
140		if (ctx->mmio_err_ff) {
141			if (!ctx->ff_page) {
142				ctx->ff_page = alloc_page(GFP_USER);
143				if (!ctx->ff_page)
144					return VM_FAULT_OOM;
145				memset(page_address(ctx->ff_page), 0xff, PAGE_SIZE);
146			}
147			get_page(ctx->ff_page);
148			vmf->page = ctx->ff_page;
149			vma->vm_page_prot = pgprot_cached(vma->vm_page_prot);
150			return 0;
151		}
152		return VM_FAULT_SIGBUS;
153	}
154
155	vm_insert_pfn(vma, address, (area + offset) >> PAGE_SHIFT);
156
157	mutex_unlock(&ctx->status_mutex);
158
159	return VM_FAULT_NOPAGE;
160}
161
162static const struct vm_operations_struct cxl_mmap_vmops = {
163	.fault = cxl_mmap_fault,
164};
165
166/*
167 * Map a per-context mmio space into the given vma.
168 */
169int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma)
170{
171	u64 start = vma->vm_pgoff << PAGE_SHIFT;
172	u64 len = vma->vm_end - vma->vm_start;
173
174	if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
175		if (start + len > ctx->afu->adapter->ps_size)
176			return -EINVAL;
177	} else {
178		if (start + len > ctx->psn_size)
179			return -EINVAL;
180	}
181
182	if (ctx->afu->current_mode != CXL_MODE_DEDICATED) {
183		/* make sure there is a valid per process space for this AFU */
184		if ((ctx->master && !ctx->afu->psa) || (!ctx->afu->pp_psa)) {
185			pr_devel("AFU doesn't support mmio space\n");
186			return -EINVAL;
187		}
188
189		/* Can't mmap until the AFU is enabled */
190		if (!ctx->afu->enabled)
191			return -EBUSY;
192	}
193
194	pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__,
195		 ctx->psn_phys, ctx->pe , ctx->master);
196
197	vma->vm_flags |= VM_IO | VM_PFNMAP;
198	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
199	vma->vm_ops = &cxl_mmap_vmops;
200	return 0;
201}
202
203/*
204 * Detach a context from the hardware. This disables interrupts and doesn't
205 * return until all outstanding interrupts for this context have completed. The
206 * hardware should no longer access *ctx after this has returned.
207 */
208int __detach_context(struct cxl_context *ctx)
209{
210	enum cxl_context_status status;
211
212	mutex_lock(&ctx->status_mutex);
213	status = ctx->status;
214	ctx->status = CLOSED;
215	mutex_unlock(&ctx->status_mutex);
216	if (status != STARTED)
217		return -EBUSY;
218
219	/* Only warn if we detached while the link was OK.
220	 * If detach fails when hw is down, we don't care.
221	 */
222	WARN_ON(cxl_ops->detach_process(ctx) &&
223		cxl_ops->link_ok(ctx->afu->adapter, ctx->afu));
224	flush_work(&ctx->fault_work); /* Only needed for dedicated process */
225
226	/*
227	 * Wait until no further interrupts are presented by the PSL
228	 * for this context.
229	 */
230	if (cxl_ops->irq_wait)
231		cxl_ops->irq_wait(ctx);
232
233	/* release the reference to the group leader and mm handling pid */
234	put_pid(ctx->pid);
235	put_pid(ctx->glpid);
236
237	cxl_ctx_put();
238	return 0;
239}
240
241/*
242 * Detach the given context from the AFU. This doesn't actually
243 * free the context but it should stop the context running in hardware
244 * (ie. prevent this context from generating any further interrupts
245 * so that it can be freed).
246 */
247void cxl_context_detach(struct cxl_context *ctx)
248{
249	int rc;
250
251	rc = __detach_context(ctx);
252	if (rc)
253		return;
254
255	afu_release_irqs(ctx, ctx);
256	wake_up_all(&ctx->wq);
257}
258
259/*
260 * Detach all contexts on the given AFU.
261 */
262void cxl_context_detach_all(struct cxl_afu *afu)
263{
264	struct cxl_context *ctx;
265	int tmp;
266
267	mutex_lock(&afu->contexts_lock);
268	idr_for_each_entry(&afu->contexts_idr, ctx, tmp) {
269		/*
270		 * Anything done in here needs to be setup before the IDR is
271		 * created and torn down after the IDR removed
272		 */
273		cxl_context_detach(ctx);
274
275		/*
276		 * We are force detaching - remove any active PSA mappings so
277		 * userspace cannot interfere with the card if it comes back.
278		 * Easiest way to exercise this is to unbind and rebind the
279		 * driver via sysfs while it is in use.
280		 */
281		mutex_lock(&ctx->mapping_lock);
282		if (ctx->mapping)
283			unmap_mapping_range(ctx->mapping, 0, 0, 1);
284		mutex_unlock(&ctx->mapping_lock);
285	}
286	mutex_unlock(&afu->contexts_lock);
287}
288
289static void reclaim_ctx(struct rcu_head *rcu)
290{
291	struct cxl_context *ctx = container_of(rcu, struct cxl_context, rcu);
292
293	free_page((u64)ctx->sstp);
294	if (ctx->ff_page)
295		__free_page(ctx->ff_page);
296	ctx->sstp = NULL;
297	if (ctx->kernelapi)
298		kfree(ctx->mapping);
299
300	if (ctx->irq_bitmap)
301		kfree(ctx->irq_bitmap);
302
303	/* Drop ref to the afu device taken during cxl_context_init */
304	cxl_afu_put(ctx->afu);
305
306	kfree(ctx);
307}
308
309void cxl_context_free(struct cxl_context *ctx)
310{
311	mutex_lock(&ctx->afu->contexts_lock);
312	idr_remove(&ctx->afu->contexts_idr, ctx->pe);
313	mutex_unlock(&ctx->afu->contexts_lock);
314	call_rcu(&ctx->rcu, reclaim_ctx);
315}