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/*
* Copyright (c) 2020 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef ZEPHYR_INCLUDE_SYS_KOBJECT_H
#define ZEPHYR_INCLUDE_SYS_KOBJECT_H
#include <stdint.h>
#include <stddef.h>
#ifdef __cplusplus
extern "C" {
#endif
struct k_thread;
struct k_mutex;
struct z_futex_data;
/**
* @brief Kernel Object Types
*
* This enumeration needs to be kept in sync with the lists of kernel objects
* and subsystems in scripts/gen_kobject_list.py, as well as the otype_to_str()
* function in kernel/userspace.c
*/
enum k_objects {
K_OBJ_ANY,
/** @cond
* Doxygen should ignore this build-time generated include file
* when generating API documentation. Enumeration values are
* generated during build by gen_kobject_list.py. It includes
* basic kernel objects (e.g. pipes and mutexes) and driver types.
*/
#include <kobj-types-enum.h>
/** @endcond
*/
K_OBJ_LAST
};
/**
* @defgroup usermode_apis User Mode APIs
* @ingroup kernel_apis
* @{
*/
#ifdef CONFIG_USERSPACE
#ifdef CONFIG_GEN_PRIV_STACKS
/* Metadata struct for K_OBJ_THREAD_STACK_ELEMENT */
struct z_stack_data {
/* Size of the entire stack object, including reserved areas */
size_t size;
/* Stack buffer for privilege mode elevations */
uint8_t *priv;
};
#endif /* CONFIG_GEN_PRIV_STACKS */
/* Object extra data. Only some objects use this, determined by object type */
union z_object_data {
/* Backing mutex for K_OBJ_SYS_MUTEX */
struct k_mutex *mutex;
/* Numerical thread ID for K_OBJ_THREAD */
unsigned int thread_id;
#ifdef CONFIG_GEN_PRIV_STACKS
/* Metadata for K_OBJ_THREAD_STACK_ELEMENT */
const struct z_stack_data *stack_data;
#else
/* Stack buffer size for K_OBJ_THREAD_STACK_ELEMENT */
size_t stack_size;
#endif /* CONFIG_GEN_PRIV_STACKS */
/* Futex wait queue and spinlock for K_OBJ_FUTEX */
struct z_futex_data *futex_data;
/* All other objects */
int unused;
};
/* Table generated by gperf, these objects are retrieved via
* z_object_find() */
struct z_object {
void *name;
uint8_t perms[CONFIG_MAX_THREAD_BYTES];
uint8_t type;
uint8_t flags;
union z_object_data data;
} __packed __aligned(4);
struct z_object_assignment {
struct k_thread *thread;
void * const *objects;
};
/**
* @brief Grant a static thread access to a list of kernel objects
*
* For threads declared with K_THREAD_DEFINE(), grant the thread access to
* a set of kernel objects. These objects do not need to be in an initialized
* state. The permissions will be granted when the threads are initialized
* in the early boot sequence.
*
* All arguments beyond the first must be pointers to kernel objects.
*
* @param name_ Name of the thread, as passed to K_THREAD_DEFINE()
*/
#define K_THREAD_ACCESS_GRANT(name_, ...) \
static void * const _CONCAT(_object_list_, name_)[] = \
{ __VA_ARGS__, NULL }; \
static const STRUCT_SECTION_ITERABLE(z_object_assignment, \
_CONCAT(_object_access_, name_)) = \
{ (&_k_thread_obj_ ## name_), \
(_CONCAT(_object_list_, name_)) }
/** Object initialized */
#define K_OBJ_FLAG_INITIALIZED BIT(0)
/** Object is Public */
#define K_OBJ_FLAG_PUBLIC BIT(1)
/** Object allocated */
#define K_OBJ_FLAG_ALLOC BIT(2)
/** Driver Object */
#define K_OBJ_FLAG_DRIVER BIT(3)
/**
* Lookup a kernel object and init its metadata if it exists
*
* Calling this on an object will make it usable from userspace.
* Intended to be called as the last statement in kernel object init
* functions.
*
* @param obj Address of the kernel object
*/
void z_object_init(const void *obj);
/**
* Grant a thread access to a kernel object
*
* The thread will be granted access to the object if the caller is from
* supervisor mode, or the caller is from user mode AND has permissions
* on both the object and the thread whose access is being granted.
*
* @param object Address of kernel object
* @param thread Thread to grant access to the object
*/
__syscall void k_object_access_grant(const void *object,
struct k_thread *thread);
/**
* Revoke a thread's access to a kernel object
*
* The thread will lose access to the object if the caller is from
* supervisor mode, or the caller is from user mode AND has permissions
* on both the object and the thread whose access is being revoked.
*
* @param object Address of kernel object
* @param thread Thread to remove access to the object
*/
void k_object_access_revoke(const void *object, struct k_thread *thread);
/**
* @brief Release an object
*
* Allows user threads to drop their own permission on an object
* Their permissions are automatically cleared when a thread terminates.
*
* @param object The object to be released
*
*/
__syscall void k_object_release(const void *object);
/**
* Grant all present and future threads access to an object
*
* If the caller is from supervisor mode, or the caller is from user mode and
* have sufficient permissions on the object, then that object will have
* permissions granted to it for *all* current and future threads running in
* the system, effectively becoming a public kernel object.
*
* Use of this API should be avoided on systems that are running untrusted code
* as it is possible for such code to derive the addresses of kernel objects
* and perform unwanted operations on them.
*
* It is not possible to revoke permissions on public objects; once public,
* any thread may use it.
*
* @param object Address of kernel object
*/
void k_object_access_all_grant(const void *object);
#else
/* LCOV_EXCL_START */
#define K_THREAD_ACCESS_GRANT(thread, ...)
/**
* @internal
*/
static inline void z_object_init(const void *obj)
{
ARG_UNUSED(obj);
}
/**
* @internal
*/
static inline void z_impl_k_object_access_grant(const void *object,
struct k_thread *thread)
{
ARG_UNUSED(object);
ARG_UNUSED(thread);
}
/**
* @internal
*/
static inline void k_object_access_revoke(const void *object,
struct k_thread *thread)
{
ARG_UNUSED(object);
ARG_UNUSED(thread);
}
/**
* @internal
*/
static inline void z_impl_k_object_release(const void *object)
{
ARG_UNUSED(object);
}
static inline void k_object_access_all_grant(const void *object)
{
ARG_UNUSED(object);
}
/* LCOV_EXCL_STOP */
#endif /* !CONFIG_USERSPACE */
#ifdef CONFIG_DYNAMIC_OBJECTS
/**
* Allocate a kernel object of a designated type
*
* This will instantiate at runtime a kernel object of the specified type,
* returning a pointer to it. The object will be returned in an uninitialized
* state, with the calling thread being granted permission on it. The memory
* for the object will be allocated out of the calling thread's resource pool.
*
* Currently, allocation of thread stacks is not supported.
*
* @param otype Requested kernel object type
* @return A pointer to the allocated kernel object, or NULL if memory wasn't
* available
*/
__syscall void *k_object_alloc(enum k_objects otype);
/**
* Allocate memory and install as a generic kernel object
*
* This is a low-level function to allocate some memory, and register that
* allocated memory in the kernel object lookup tables with type K_OBJ_ANY.
* Initialization state and thread permissions will be cleared. The
* returned z_object's data value will be uninitialized.
*
* Most users will want to use k_object_alloc() instead.
*
* Memory allocated will be drawn from the calling thread's reasource pool
* and may be freed later by passing the actual object pointer (found
* in the returned z_object's 'name' member) to k_object_free().
*
* @param align Required memory alignment for the allocated object
* @param size Size of the allocated object
* @return NULL on insufficient memory
* @return A pointer to the associated z_object that is installed in the
* kernel object tables
*/
struct z_object *z_dynamic_object_aligned_create(size_t align, size_t size);
/**
* Allocate memory and install as a generic kernel object
*
* This is a low-level function to allocate some memory, and register that
* allocated memory in the kernel object lookup tables with type K_OBJ_ANY.
* Initialization state and thread permissions will be cleared. The
* returned z_object's data value will be uninitialized.
*
* Most users will want to use k_object_alloc() instead.
*
* Memory allocated will be drawn from the calling thread's reasource pool
* and may be freed later by passing the actual object pointer (found
* in the returned z_object's 'name' member) to k_object_free().
*
* @param size Size of the allocated object
* @return NULL on insufficient memory
* @return A pointer to the associated z_object that is installed in the
* kernel object tables
*/
static inline struct z_object *z_dynamic_object_create(size_t size)
{
return z_dynamic_object_aligned_create(0, size);
}
/**
* Free a kernel object previously allocated with k_object_alloc()
*
* This will return memory for a kernel object back to resource pool it was
* allocated from. Care must be exercised that the object will not be used
* during or after when this call is made.
*
* @param obj Pointer to the kernel object memory address.
*/
void k_object_free(void *obj);
#else
/* LCOV_EXCL_START */
static inline void *z_impl_k_object_alloc(enum k_objects otype)
{
ARG_UNUSED(otype);
return NULL;
}
static inline struct z_object *z_dynamic_object_aligned_create(size_t align,
size_t size)
{
ARG_UNUSED(align);
ARG_UNUSED(size);
return NULL;
}
static inline struct z_object *z_dynamic_object_create(size_t size)
{
ARG_UNUSED(size);
return NULL;
}
/**
* @brief Free an object
*
* @param obj
*/
static inline void k_object_free(void *obj)
{
ARG_UNUSED(obj);
}
/* LCOV_EXCL_STOP */
#endif /* CONFIG_DYNAMIC_OBJECTS */
/** @} */
#include <syscalls/kobject.h>
#ifdef __cplusplus
}
#endif
#endif