Commit 28b24c1f authored by Sasha Levin's avatar Sasha Levin Committed by Linus Torvalds

mm: cma: debugfs interface

I've noticed that there is no interfaces exposed by CMA which would let me
fuzz what's going on in there.

This small patchset exposes some information out to userspace, plus adds
the ability to trigger allocation and freeing from userspace.

This patch (of 3):

Implement a simple debugfs interface to expose information about CMA areas
in the system.

Useful for testing/sanity checks for CMA since it was impossible to
previously retrieve this information in userspace.
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
Acked-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 19c07d5e
......@@ -517,6 +517,12 @@ config CMA_DEBUG
processing calls such as dma_alloc_from_contiguous().
This option does not affect warning and error messages.
config CMA_DEBUGFS
bool "CMA debugfs interface"
depends on CMA && DEBUG_FS
help
Turns on the DebugFS interface for CMA.
config CMA_AREAS
int "Maximum count of the CMA areas"
depends on CMA
......
......@@ -76,3 +76,4 @@ obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
obj-$(CONFIG_CMA) += cma.o
obj-$(CONFIG_MEMORY_BALLOON) += balloon_compaction.o
obj-$(CONFIG_PAGE_EXTENSION) += page_ext.o
obj-$(CONFIG_CMA_DEBUGFS) += cma_debug.o
......@@ -35,16 +35,10 @@
#include <linux/highmem.h>
#include <linux/io.h>
struct cma {
unsigned long base_pfn;
unsigned long count;
unsigned long *bitmap;
unsigned int order_per_bit; /* Order of pages represented by one bit */
struct mutex lock;
};
static struct cma cma_areas[MAX_CMA_AREAS];
static unsigned cma_area_count;
#include "cma.h"
struct cma cma_areas[MAX_CMA_AREAS];
unsigned cma_area_count;
static DEFINE_MUTEX(cma_mutex);
phys_addr_t cma_get_base(struct cma *cma)
......@@ -77,11 +71,6 @@ static unsigned long cma_bitmap_aligned_offset(struct cma *cma, int align_order)
- cma->base_pfn) >> cma->order_per_bit;
}
static unsigned long cma_bitmap_maxno(struct cma *cma)
{
return cma->count >> cma->order_per_bit;
}
static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
unsigned long pages)
{
......
#ifndef __MM_CMA_H__
#define __MM_CMA_H__
struct cma {
unsigned long base_pfn;
unsigned long count;
unsigned long *bitmap;
unsigned int order_per_bit; /* Order of pages represented by one bit */
struct mutex lock;
};
extern struct cma cma_areas[MAX_CMA_AREAS];
extern unsigned cma_area_count;
static unsigned long cma_bitmap_maxno(struct cma *cma)
{
return cma->count >> cma->order_per_bit;
}
#endif
/*
* CMA DebugFS Interface
*
* Copyright (c) 2015 Sasha Levin <sasha.levin@oracle.com>
*/
#include <linux/debugfs.h>
#include <linux/cma.h>
#include "cma.h"
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 void cma_debugfs_add_one(struct cma *cma, int idx)
{
struct dentry *tmp;
char name[16];
int u32s;
sprintf(name, "cma-%d", idx);
tmp = debugfs_create_dir(name, cma_debugfs_root);
debugfs_create_file("base_pfn", S_IRUGO, tmp,
&cma->base_pfn, &cma_debugfs_fops);
debugfs_create_file("count", S_IRUGO, tmp,
&cma->count, &cma_debugfs_fops);
debugfs_create_file("order_per_bit", S_IRUGO, tmp,
&cma->order_per_bit, &cma_debugfs_fops);
u32s = DIV_ROUND_UP(cma_bitmap_maxno(cma), BITS_PER_BYTE * sizeof(u32));
debugfs_create_u32_array("bitmap", S_IRUGO, 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);
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