// SPDX-License-Identifier: GPL-2.0 /* * CMA DebugFS Interface * * Copyright (c) 2015 Sasha Levin <sasha.levin@oracle.com> */ #include <linux/debugfs.h> #include <linux/cma.h> #include <linux/list.h> #include <linux/kernel.h> #include <linux/slab.h> #include <linux/mm_types.h> #include "cma.h" struct cma_mem { struct hlist_node node; struct page *p; unsigned long n; }; static struct dentry *cma_debugfs_root; static int cma_debugfs_get(void *data, u64 *val) { unsigned long *p = data; *val = *p; return 0; } DEFINE_SIMPLE_ATTRIBUTE(cma_debugfs_fops, cma_debugfs_get, NULL, "%llu\n"); static int cma_used_get(void *data, u64 *val) { struct cma *cma = data; unsigned long used; mutex_lock(&cma->lock); /* pages counter is smaller than sizeof(int) */ used = bitmap_weight(cma->bitmap, (int)cma_bitmap_maxno(cma)); mutex_unlock(&cma->lock); *val = (u64)used << cma->order_per_bit; return 0; } DEFINE_SIMPLE_ATTRIBUTE(cma_used_fops, cma_used_get, NULL, "%llu\n"); static int cma_maxchunk_get(void *data, u64 *val) { struct cma *cma = data; unsigned long maxchunk = 0; unsigned long start, end = 0; unsigned long bitmap_maxno = cma_bitmap_maxno(cma); mutex_lock(&cma->lock); for (;;) { start = find_next_zero_bit(cma->bitmap, bitmap_maxno, end); if (start >= cma->count) break; end = find_next_bit(cma->bitmap, bitmap_maxno, start); maxchunk = max(end - start, maxchunk); } mutex_unlock(&cma->lock); *val = (u64)maxchunk << cma->order_per_bit; return 0; } DEFINE_SIMPLE_ATTRIBUTE(cma_maxchunk_fops, cma_maxchunk_get, NULL, "%llu\n"); static void cma_add_to_cma_mem_list(struct cma *cma, struct cma_mem *mem) { spin_lock(&cma->mem_head_lock); hlist_add_head(&mem->node, &cma->mem_head); spin_unlock(&cma->mem_head_lock); } static struct cma_mem *cma_get_entry_from_list(struct cma *cma) { struct cma_mem *mem = NULL; spin_lock(&cma->mem_head_lock); if (!hlist_empty(&cma->mem_head)) { mem = hlist_entry(cma->mem_head.first, struct cma_mem, node); hlist_del_init(&mem->node); } spin_unlock(&cma->mem_head_lock); return mem; } static int cma_free_mem(struct cma *cma, int count) { struct cma_mem *mem = NULL; while (count) { mem = cma_get_entry_from_list(cma); if (mem == NULL) return 0; if (mem->n <= count) { cma_release(cma, mem->p, mem->n); count -= mem->n; kfree(mem); } else if (cma->order_per_bit == 0) { cma_release(cma, mem->p, count); mem->p += count; mem->n -= count; count = 0; cma_add_to_cma_mem_list(cma, mem); } else { pr_debug("cma: cannot release partial block when order_per_bit != 0\n"); cma_add_to_cma_mem_list(cma, mem); break; } } return 0; } static int cma_free_write(void *data, u64 val) { int pages = val; struct cma *cma = data; return cma_free_mem(cma, pages); } DEFINE_SIMPLE_ATTRIBUTE(cma_free_fops, NULL, cma_free_write, "%llu\n"); static int cma_alloc_mem(struct cma *cma, int count) { struct cma_mem *mem; struct page *p; mem = kzalloc(sizeof(*mem), GFP_KERNEL); if (!mem) return -ENOMEM; p = cma_alloc(cma, count, 0, false); if (!p) { kfree(mem); return -ENOMEM; } mem->p = p; mem->n = count; cma_add_to_cma_mem_list(cma, mem); return 0; } static int cma_alloc_write(void *data, u64 val) { int pages = val; struct cma *cma = data; return cma_alloc_mem(cma, pages); } DEFINE_SIMPLE_ATTRIBUTE(cma_alloc_fops, NULL, cma_alloc_write, "%llu\n"); static void cma_debugfs_add_one(struct cma *cma, int idx) { struct dentry *tmp; char name[16]; int u32s; scnprintf(name, sizeof(name), "cma-%s", cma->name); tmp = debugfs_create_dir(name, cma_debugfs_root); debugfs_create_file("alloc", 0200, tmp, cma, &cma_alloc_fops); debugfs_create_file("free", 0200, tmp, cma, &cma_free_fops); debugfs_create_file("base_pfn", 0444, tmp, &cma->base_pfn, &cma_debugfs_fops); debugfs_create_file("count", 0444, tmp, &cma->count, &cma_debugfs_fops); debugfs_create_file("order_per_bit", 0444, tmp, &cma->order_per_bit, &cma_debugfs_fops); debugfs_create_file("used", 0444, tmp, cma, &cma_used_fops); debugfs_create_file("maxchunk", 0444, tmp, cma, &cma_maxchunk_fops); u32s = DIV_ROUND_UP(cma_bitmap_maxno(cma), BITS_PER_BYTE * sizeof(u32)); debugfs_create_u32_array("bitmap", 0444, tmp, (u32 *)cma->bitmap, u32s); } static int __init cma_debugfs_init(void) { int i; cma_debugfs_root = debugfs_create_dir("cma", NULL); if (!cma_debugfs_root) return -ENOMEM; for (i = 0; i < cma_area_count; i++) cma_debugfs_add_one(&cma_areas[i], i); return 0; } late_initcall(cma_debugfs_init);