linux/mm/kfence/kfence.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Kernel Electric-Fence (KFENCE). For more info please see
 * Documentation/dev-tools/kfence.rst.
 *
 * Copyright (C) 2020, Google LLC.
 */

#ifndef MM_KFENCE_KFENCE_H
#define MM_KFENCE_KFENCE_H

#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/types.h>

#include "../slab.h" /* for struct kmem_cache */

/*
 * Get the canary byte pattern for @addr. Use a pattern that varies based on the
 * lower 3 bits of the address, to detect memory corruptions with higher
 * probability, where similar constants are used.
 */
#define KFENCE_CANARY_PATTERN_U8(addr) …

/*
 * Define a continuous 8-byte canary starting from a multiple of 8. The canary
 * of each byte is only related to the lowest three bits of its address, so the
 * canary of every 8 bytes is the same. 64-bit memory can be filled and checked
 * at a time instead of byte by byte to improve performance.
 */
#define KFENCE_CANARY_PATTERN_U64 …

/* Maximum stack depth for reports. */
#define KFENCE_STACK_DEPTH …

/* KFENCE object states. */
enum kfence_object_state { … };

/* Alloc/free tracking information. */
struct kfence_track { … };

/* KFENCE metadata per guarded allocation. */
struct kfence_metadata { … };

#define KFENCE_METADATA_SIZE …

extern struct kfence_metadata *kfence_metadata;

static inline struct kfence_metadata *addr_to_metadata(unsigned long addr)
{ … }

/* KFENCE error types for report generation. */
enum kfence_error_type { … };

void kfence_report_error(unsigned long address, bool is_write, struct pt_regs *regs,
			 const struct kfence_metadata *meta, enum kfence_error_type type);

void kfence_print_object(struct seq_file *seq, const struct kfence_metadata *meta);

#endif /* MM_KFENCE_KFENCE_H */