1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * CMA DebugFS Interface 4 * 5 * Copyright (c) 2015 Sasha Levin <sasha.levin@oracle.com> 6 */ 7 8 9 #include <linux/debugfs.h> 10 #include <linux/cma.h> 11 #include <linux/list.h> 12 #include <linux/kernel.h> 13 #include <linux/slab.h> 14 #include <linux/mm_types.h> 15 16 #include "cma.h" 17 18 struct cma_mem { 19 struct hlist_node node; 20 struct page *p; 21 unsigned long n; 22 }; 23 24 static int cma_debugfs_get(void *data, u64 *val) 25 { 26 unsigned long *p = data; 27 28 *val = *p; 29 30 return 0; 31 } 32 DEFINE_DEBUGFS_ATTRIBUTE(cma_debugfs_fops, cma_debugfs_get, NULL, "%llu\n"); 33 34 static int cma_used_get(void *data, u64 *val) 35 { 36 struct cma *cma = data; 37 unsigned long used; 38 39 spin_lock_irq(&cma->lock); 40 /* pages counter is smaller than sizeof(int) */ 41 used = bitmap_weight(cma->bitmap, (int)cma_bitmap_maxno(cma)); 42 spin_unlock_irq(&cma->lock); 43 *val = (u64)used << cma->order_per_bit; 44 45 return 0; 46 } 47 DEFINE_DEBUGFS_ATTRIBUTE(cma_used_fops, cma_used_get, NULL, "%llu\n"); 48 49 static int cma_maxchunk_get(void *data, u64 *val) 50 { 51 struct cma *cma = data; 52 unsigned long maxchunk = 0; 53 unsigned long start, end = 0; 54 unsigned long bitmap_maxno = cma_bitmap_maxno(cma); 55 56 spin_lock_irq(&cma->lock); 57 for (;;) { 58 start = find_next_zero_bit(cma->bitmap, bitmap_maxno, end); 59 if (start >= bitmap_maxno) 60 break; 61 end = find_next_bit(cma->bitmap, bitmap_maxno, start); 62 maxchunk = max(end - start, maxchunk); 63 } 64 spin_unlock_irq(&cma->lock); 65 *val = (u64)maxchunk << cma->order_per_bit; 66 67 return 0; 68 } 69 DEFINE_DEBUGFS_ATTRIBUTE(cma_maxchunk_fops, cma_maxchunk_get, NULL, "%llu\n"); 70 71 static void cma_add_to_cma_mem_list(struct cma *cma, struct cma_mem *mem) 72 { 73 spin_lock(&cma->mem_head_lock); 74 hlist_add_head(&mem->node, &cma->mem_head); 75 spin_unlock(&cma->mem_head_lock); 76 } 77 78 static struct cma_mem *cma_get_entry_from_list(struct cma *cma) 79 { 80 struct cma_mem *mem = NULL; 81 82 spin_lock(&cma->mem_head_lock); 83 if (!hlist_empty(&cma->mem_head)) { 84 mem = hlist_entry(cma->mem_head.first, struct cma_mem, node); 85 hlist_del_init(&mem->node); 86 } 87 spin_unlock(&cma->mem_head_lock); 88 89 return mem; 90 } 91 92 static int cma_free_mem(struct cma *cma, int count) 93 { 94 struct cma_mem *mem = NULL; 95 96 while (count) { 97 mem = cma_get_entry_from_list(cma); 98 if (mem == NULL) 99 return 0; 100 101 if (mem->n <= count) { 102 cma_release(cma, mem->p, mem->n); 103 count -= mem->n; 104 kfree(mem); 105 } else if (cma->order_per_bit == 0) { 106 cma_release(cma, mem->p, count); 107 mem->p += count; 108 mem->n -= count; 109 count = 0; 110 cma_add_to_cma_mem_list(cma, mem); 111 } else { 112 pr_debug("cma: cannot release partial block when order_per_bit != 0\n"); 113 cma_add_to_cma_mem_list(cma, mem); 114 break; 115 } 116 } 117 118 return 0; 119 120 } 121 122 static int cma_free_write(void *data, u64 val) 123 { 124 int pages = val; 125 struct cma *cma = data; 126 127 return cma_free_mem(cma, pages); 128 } 129 DEFINE_DEBUGFS_ATTRIBUTE(cma_free_fops, NULL, cma_free_write, "%llu\n"); 130 131 static int cma_alloc_mem(struct cma *cma, int count) 132 { 133 struct cma_mem *mem; 134 struct page *p; 135 136 mem = kzalloc(sizeof(*mem), GFP_KERNEL); 137 if (!mem) 138 return -ENOMEM; 139 140 p = cma_alloc(cma, count, 0, false); 141 if (!p) { 142 kfree(mem); 143 return -ENOMEM; 144 } 145 146 mem->p = p; 147 mem->n = count; 148 149 cma_add_to_cma_mem_list(cma, mem); 150 151 return 0; 152 } 153 154 static int cma_alloc_write(void *data, u64 val) 155 { 156 int pages = val; 157 struct cma *cma = data; 158 159 return cma_alloc_mem(cma, pages); 160 } 161 DEFINE_DEBUGFS_ATTRIBUTE(cma_alloc_fops, NULL, cma_alloc_write, "%llu\n"); 162 163 static void cma_debugfs_add_one(struct cma *cma, struct dentry *root_dentry) 164 { 165 struct dentry *tmp; 166 167 tmp = debugfs_create_dir(cma->name, root_dentry); 168 169 debugfs_create_file("alloc", 0200, tmp, cma, &cma_alloc_fops); 170 debugfs_create_file("free", 0200, tmp, cma, &cma_free_fops); 171 debugfs_create_file("base_pfn", 0444, tmp, 172 &cma->base_pfn, &cma_debugfs_fops); 173 debugfs_create_file("count", 0444, tmp, &cma->count, &cma_debugfs_fops); 174 debugfs_create_file("order_per_bit", 0444, tmp, 175 &cma->order_per_bit, &cma_debugfs_fops); 176 debugfs_create_file("used", 0444, tmp, cma, &cma_used_fops); 177 debugfs_create_file("maxchunk", 0444, tmp, cma, &cma_maxchunk_fops); 178 179 cma->dfs_bitmap.array = (u32 *)cma->bitmap; 180 cma->dfs_bitmap.n_elements = DIV_ROUND_UP(cma_bitmap_maxno(cma), 181 BITS_PER_BYTE * sizeof(u32)); 182 debugfs_create_u32_array("bitmap", 0444, tmp, &cma->dfs_bitmap); 183 } 184 185 static int __init cma_debugfs_init(void) 186 { 187 struct dentry *cma_debugfs_root; 188 int i; 189 190 cma_debugfs_root = debugfs_create_dir("cma", NULL); 191 192 for (i = 0; i < cma_area_count; i++) 193 cma_debugfs_add_one(&cma_areas[i], cma_debugfs_root); 194 195 return 0; 196 } 197 late_initcall(cma_debugfs_init); 198