2 * Copyright 2014 IBM Corp.
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.
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>
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>
27 * Allocates space for a CXL context.
29 struct cxl_context *cxl_context_alloc(void)
31 return kzalloc(sizeof(struct cxl_context), GFP_KERNEL);
35 * Initialises a CXL context.
37 int cxl_context_init(struct cxl_context *ctx, struct cxl_afu *afu, bool master,
38 struct address_space *mapping)
42 spin_lock_init(&ctx->sste_lock);
45 ctx->pid = ctx->glpid = NULL; /* Set in start work ioctl */
46 mutex_init(&ctx->mapping_lock);
47 ctx->mapping = mapping;
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).
56 i = cxl_alloc_sst(ctx);
60 INIT_WORK(&ctx->fault_work, cxl_handle_fault);
62 init_waitqueue_head(&ctx->wq);
63 spin_lock_init(&ctx->lock);
65 ctx->irq_bitmap = NULL;
66 ctx->pending_irq = false;
67 ctx->pending_fault = false;
68 ctx->pending_afu_err = false;
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.
77 for (i = 0; i < CXL_IRQ_RANGES; i++)
78 ctx->irqs.range[i] = 0;
80 mutex_init(&ctx->status_mutex);
85 * Allocating IDR! We better make sure everything's setup that
86 * dereferences from it.
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);
93 mutex_unlock(&afu->contexts_lock);
98 ctx->elem = &ctx->afu->spa[i];
99 ctx->pe_inserted = false;
102 * take a ref on the afu so that it stays alive at-least till
103 * this context is reclaimed inside reclaim_ctx.
109 static int cxl_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
111 struct cxl_context *ctx = vma->vm_file->private_data;
112 unsigned long address = (unsigned long)vmf->virtual_address;
115 offset = vmf->pgoff << PAGE_SHIFT;
117 pr_devel("%s: pe: %i address: 0x%lx offset: 0x%llx\n",
118 __func__, ctx->pe, address, offset);
120 if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
121 area = ctx->afu->psn_phys;
122 if (offset >= ctx->afu->adapter->ps_size)
123 return VM_FAULT_SIGBUS;
125 area = ctx->psn_phys;
126 if (offset >= ctx->psn_size)
127 return VM_FAULT_SIGBUS;
130 mutex_lock(&ctx->status_mutex);
132 if (ctx->status != STARTED) {
133 mutex_unlock(&ctx->status_mutex);
134 pr_devel("%s: Context not started, failing problem state access\n", __func__);
135 if (ctx->mmio_err_ff) {
137 ctx->ff_page = alloc_page(GFP_USER);
140 memset(page_address(ctx->ff_page), 0xff, PAGE_SIZE);
142 get_page(ctx->ff_page);
143 vmf->page = ctx->ff_page;
144 vma->vm_page_prot = pgprot_cached(vma->vm_page_prot);
147 return VM_FAULT_SIGBUS;
150 vm_insert_pfn(vma, address, (area + offset) >> PAGE_SHIFT);
152 mutex_unlock(&ctx->status_mutex);
154 return VM_FAULT_NOPAGE;
157 static const struct vm_operations_struct cxl_mmap_vmops = {
158 .fault = cxl_mmap_fault,
162 * Map a per-context mmio space into the given vma.
164 int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma)
166 u64 start = vma->vm_pgoff << PAGE_SHIFT;
167 u64 len = vma->vm_end - vma->vm_start;
169 if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
170 if (start + len > ctx->afu->adapter->ps_size)
173 if (start + len > ctx->psn_size)
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");
184 /* Can't mmap until the AFU is enabled */
185 if (!ctx->afu->enabled)
189 pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__,
190 ctx->psn_phys, ctx->pe , ctx->master);
192 vma->vm_flags |= VM_IO | VM_PFNMAP;
193 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
194 vma->vm_ops = &cxl_mmap_vmops;
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.
203 int __detach_context(struct cxl_context *ctx)
205 enum cxl_context_status status;
207 mutex_lock(&ctx->status_mutex);
208 status = ctx->status;
209 ctx->status = CLOSED;
210 mutex_unlock(&ctx->status_mutex);
211 if (status != STARTED)
214 /* Only warn if we detached while the link was OK.
215 * If detach fails when hw is down, we don't care.
217 WARN_ON(cxl_detach_process(ctx) &&
218 cxl_adapter_link_ok(ctx->afu->adapter));
219 flush_work(&ctx->fault_work); /* Only needed for dedicated process */
221 /* release the reference to the group leader and mm handling pid */
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).
235 void cxl_context_detach(struct cxl_context *ctx)
239 rc = __detach_context(ctx);
243 afu_release_irqs(ctx, ctx);
244 wake_up_all(&ctx->wq);
248 * Detach all contexts on the given AFU.
250 void cxl_context_detach_all(struct cxl_afu *afu)
252 struct cxl_context *ctx;
255 mutex_lock(&afu->contexts_lock);
256 idr_for_each_entry(&afu->contexts_idr, ctx, tmp) {
258 * Anything done in here needs to be setup before the IDR is
259 * created and torn down after the IDR removed
261 cxl_context_detach(ctx);
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.
269 mutex_lock(&ctx->mapping_lock);
271 unmap_mapping_range(ctx->mapping, 0, 0, 1);
272 mutex_unlock(&ctx->mapping_lock);
274 mutex_unlock(&afu->contexts_lock);
277 static void reclaim_ctx(struct rcu_head *rcu)
279 struct cxl_context *ctx = container_of(rcu, struct cxl_context, rcu);
281 free_page((u64)ctx->sstp);
283 __free_page(ctx->ff_page);
289 kfree(ctx->irq_bitmap);
291 /* Drop ref to the afu device taken during cxl_context_init */
292 cxl_afu_put(ctx->afu);
297 void cxl_context_free(struct cxl_context *ctx)
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);