Provides a userspace interface to trigger a CMA allocation.
Usage:
echo [pages] > alloc
This would provide testing/fuzzing access to the CMA allocation paths.
Signed-off-by: Sasha Levin <sasha.le...@oracle.com>
---
mm/cma_debug.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 58 insertions(+)
diff --git a/mm/cma_debug.c b/mm/cma_debug.c
index 3a25413..eda0a41 100644
--- a/mm/cma_debug.c
+++ b/mm/cma_debug.c
@@ -7,9 +7,22 @@
#include <linux/debugfs.h>
#include <linux/cma.h>
+#include <linux/list.h>
+#include <linux/kernel.h>
+#include <linux/dma-contiguous.h>
+#include <linux/slab.h>
#include "cma.h"
+struct cma_mem {
+ struct hlist_node node;
+ struct page *p;
+ unsigned long n;
+};
+
+static HLIST_HEAD(cma_mem_head);
+static DEFINE_SPINLOCK(cma_mem_head_lock);
+
static struct dentry *cma_debugfs_root;
static int cma_debugfs_get(void *data, u64 *val)
@@ -44,6 +57,48 @@ static void cma_debugfs_add_one(struct cma *cma, int idx)
debugfs_create_u32_array("bitmap", S_IRUGO, tmp, (u32*)cma->bitmap,
u32s);
}
+static void cma_add_to_cma_mem_list(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 int cma_alloc_mem(int count)
+{
+ struct cma_mem *mem;
+ struct page *p;
+
+ mem = kzalloc(sizeof(*mem), GFP_KERNEL);
+ if (!mem)
+ return -ENOMEM;
+
+ p = cma_alloc(dma_contiguous_default_area, count, CONFIG_CMA_ALIGNMENT);
+ if (!p) {
+ pr_info("CMA: Allocation failed.\n");
+ kfree(mem);
+ return -ENOMEM;
+ }
+
+ pr_info("CMA: Allocated %d pages at %p\n", count, p);
+
+ mem->p = p;
+ mem->n = count;
+
+ cma_add_to_cma_mem_list(mem);
+
+ return 0;
+}
+
+static int cma_alloc_write(void *data, u64 val)
+{
+ int pages = val;
+
+ return cma_alloc_mem(pages);
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(cma_alloc_fops, NULL, cma_alloc_write, "%llu\n");
+
static int __init cma_debugfs_init(void)
{
int i;
@@ -52,6 +107,9 @@ static int __init cma_debugfs_init(void)
if (!cma_debugfs_root)
return -ENOMEM;
+ debugfs_create_file("alloc", S_IWUSR, cma_debugfs_root, NULL,
+ &cma_alloc_fops);
+
for (i = 0; i < cma_area_count; i++)
cma_debugfs_add_one(&cma_areas[i], i);
--
1.7.10.4
--
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