/* SPDX-License-Identifier: GPL-2.0 */
/*
 * code tagging framework
 */
#ifndef _LINUX_CODETAG_H
#define _LINUX_CODETAG_H

#include <linux/types.h>

struct codetag_iterator;
struct codetag_type;
struct codetag_module;
struct seq_buf;
struct module;

#define CODETAG_SECTION_START_PREFIX    "__start_"
#define CODETAG_SECTION_STOP_PREFIX     "__stop_"

/* codetag flags */
#define CODETAG_FLAG_INACCURATE (1 << 0)

/*
 * An instance of this structure is created in a special ELF section at every
 * code location being tagged.  At runtime, the special section is treated as
 * an array of these.
 */
struct codetag {
        unsigned int flags;
        unsigned int lineno;
        const char *modname;
        const char *function;
        const char *filename;
} __aligned(8);

union codetag_ref {
        struct codetag *ct;
};

struct codetag_type_desc {
        const char *section;
        size_t tag_size;
        int (*module_load)(struct module *mod,
                           struct codetag *start, struct codetag *end);
        void (*module_unload)(struct module *mod,
                              struct codetag *start, struct codetag *end);
#ifdef CONFIG_MODULES
        void (*module_replaced)(struct module *mod, struct module *new_mod);
        bool (*needs_section_mem)(struct module *mod, unsigned long size);
        void *(*alloc_section_mem)(struct module *mod, unsigned long size,
                                   unsigned int prepend, unsigned long align);
        void (*free_section_mem)(struct module *mod, bool used);
#endif
};

struct codetag_iterator {
        struct codetag_type *cttype;
        struct codetag_module *cmod;
        unsigned long mod_id;
        struct codetag *ct;
        unsigned long mod_seq;
};

#ifdef MODULE
#define CT_MODULE_NAME KBUILD_MODNAME
#else
#define CT_MODULE_NAME NULL
#endif

#define CODE_TAG_INIT {                                 \
        .modname        = CT_MODULE_NAME,               \
        .function       = __func__,                     \
        .filename       = __FILE__,                     \
        .lineno         = __LINE__,                     \
        .flags          = 0,                            \
}

void codetag_lock_module_list(struct codetag_type *cttype, bool lock);
bool codetag_trylock_module_list(struct codetag_type *cttype);
struct codetag_iterator codetag_get_ct_iter(struct codetag_type *cttype);
struct codetag *codetag_next_ct(struct codetag_iterator *iter);

void codetag_to_text(struct seq_buf *out, struct codetag *ct);

struct codetag_type *
codetag_register_type(const struct codetag_type_desc *desc);

#if defined(CONFIG_CODE_TAGGING) && defined(CONFIG_MODULES)

bool codetag_needs_module_section(struct module *mod, const char *name,
                                  unsigned long size);
void *codetag_alloc_module_section(struct module *mod, const char *name,
                                   unsigned long size, unsigned int prepend,
                                   unsigned long align);
void codetag_free_module_sections(struct module *mod);
void codetag_module_replaced(struct module *mod, struct module *new_mod);
int codetag_load_module(struct module *mod);
void codetag_unload_module(struct module *mod);

#else /* defined(CONFIG_CODE_TAGGING) && defined(CONFIG_MODULES) */

static inline bool
codetag_needs_module_section(struct module *mod, const char *name,
                             unsigned long size) { return false; }
static inline void *
codetag_alloc_module_section(struct module *mod, const char *name,
                             unsigned long size, unsigned int prepend,
                             unsigned long align) { return NULL; }
static inline void codetag_free_module_sections(struct module *mod) {}
static inline void codetag_module_replaced(struct module *mod, struct module *new_mod) {}
static inline int codetag_load_module(struct module *mod) { return 0; }
static inline void codetag_unload_module(struct module *mod) {}

#endif /* defined(CONFIG_CODE_TAGGING) && defined(CONFIG_MODULES) */

#endif /* _LINUX_CODETAG_H */