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 */ 37 int cxl_context_init(struct cxl_context *ctx, struct cxl_afu *afu, bool master) 38 { 39 int i; 40 41 spin_lock_init(&ctx->sste_lock); 42 ctx->afu = afu; 43 ctx->master = master; 44 ctx->pid = NULL; /* Set in start work ioctl */ 45 46 /* 47 * Allocate the segment table before we put it in the IDR so that we 48 * can always access it when dereferenced from IDR. For the same 49 * reason, the segment table is only destroyed after the context is 50 * removed from the IDR. Access to this in the IOCTL is protected by 51 * Linux filesytem symantics (can't IOCTL until open is complete). 52 */ 53 i = cxl_alloc_sst(ctx); 54 if (i) 55 return i; 56 57 INIT_WORK(&ctx->fault_work, cxl_handle_fault); 58 59 init_waitqueue_head(&ctx->wq); 60 spin_lock_init(&ctx->lock); 61 62 ctx->irq_bitmap = NULL; 63 ctx->pending_irq = false; 64 ctx->pending_fault = false; 65 ctx->pending_afu_err = false; 66 67 /* 68 * When we have to destroy all contexts in cxl_context_detach_all() we 69 * end up with afu_release_irqs() called from inside a 70 * idr_for_each_entry(). Hence we need to make sure that anything 71 * dereferenced from this IDR is ok before we allocate the IDR here. 72 * This clears out the IRQ ranges to ensure this. 73 */ 74 for (i = 0; i < CXL_IRQ_RANGES; i++) 75 ctx->irqs.range[i] = 0; 76 77 mutex_init(&ctx->status_mutex); 78 79 ctx->status = OPENED; 80 81 /* 82 * Allocating IDR! We better make sure everything's setup that 83 * dereferences from it. 84 */ 85 idr_preload(GFP_KERNEL); 86 spin_lock(&afu->contexts_lock); 87 i = idr_alloc(&ctx->afu->contexts_idr, ctx, 0, 88 ctx->afu->num_procs, GFP_NOWAIT); 89 spin_unlock(&afu->contexts_lock); 90 idr_preload_end(); 91 if (i < 0) 92 return i; 93 94 ctx->pe = i; 95 ctx->elem = &ctx->afu->spa[i]; 96 ctx->pe_inserted = false; 97 return 0; 98 } 99 100 /* 101 * Map a per-context mmio space into the given vma. 102 */ 103 int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma) 104 { 105 u64 len = vma->vm_end - vma->vm_start; 106 len = min(len, ctx->psn_size); 107 108 if (ctx->afu->current_mode == CXL_MODE_DEDICATED) { 109 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 110 return vm_iomap_memory(vma, ctx->afu->psn_phys, ctx->afu->adapter->ps_size); 111 } 112 113 /* make sure there is a valid per process space for this AFU */ 114 if ((ctx->master && !ctx->afu->psa) || (!ctx->afu->pp_psa)) { 115 pr_devel("AFU doesn't support mmio space\n"); 116 return -EINVAL; 117 } 118 119 /* Can't mmap until the AFU is enabled */ 120 if (!ctx->afu->enabled) 121 return -EBUSY; 122 123 pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__, 124 ctx->psn_phys, ctx->pe , ctx->master); 125 126 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 127 return vm_iomap_memory(vma, ctx->psn_phys, len); 128 } 129 130 /* 131 * Detach a context from the hardware. This disables interrupts and doesn't 132 * return until all outstanding interrupts for this context have completed. The 133 * hardware should no longer access *ctx after this has returned. 134 */ 135 static void __detach_context(struct cxl_context *ctx) 136 { 137 enum cxl_context_status status; 138 139 mutex_lock(&ctx->status_mutex); 140 status = ctx->status; 141 ctx->status = CLOSED; 142 mutex_unlock(&ctx->status_mutex); 143 if (status != STARTED) 144 return; 145 146 WARN_ON(cxl_detach_process(ctx)); 147 afu_release_irqs(ctx); 148 flush_work(&ctx->fault_work); /* Only needed for dedicated process */ 149 wake_up_all(&ctx->wq); 150 } 151 152 /* 153 * Detach the given context from the AFU. This doesn't actually 154 * free the context but it should stop the context running in hardware 155 * (ie. prevent this context from generating any further interrupts 156 * so that it can be freed). 157 */ 158 void cxl_context_detach(struct cxl_context *ctx) 159 { 160 __detach_context(ctx); 161 } 162 163 /* 164 * Detach all contexts on the given AFU. 165 */ 166 void cxl_context_detach_all(struct cxl_afu *afu) 167 { 168 struct cxl_context *ctx; 169 int tmp; 170 171 rcu_read_lock(); 172 idr_for_each_entry(&afu->contexts_idr, ctx, tmp) 173 /* 174 * Anything done in here needs to be setup before the IDR is 175 * created and torn down after the IDR removed 176 */ 177 __detach_context(ctx); 178 rcu_read_unlock(); 179 } 180 181 void cxl_context_free(struct cxl_context *ctx) 182 { 183 spin_lock(&ctx->afu->contexts_lock); 184 idr_remove(&ctx->afu->contexts_idr, ctx->pe); 185 spin_unlock(&ctx->afu->contexts_lock); 186 synchronize_rcu(); 187 188 free_page((u64)ctx->sstp); 189 ctx->sstp = NULL; 190 191 put_pid(ctx->pid); 192 kfree(ctx); 193 } 194