syscall.h

Go to the documentation of this file.

/*
 * Copyright (c) 2017, Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */
 
 
#ifndef ZEPHYR_INCLUDE_SYSCALL_H_
#define ZEPHYR_INCLUDE_SYSCALL_H_
 
#include <zephyr/syscall_list.h>
#include <zephyr/arch/syscall.h>
#include <stdbool.h>
 
#ifndef _ASMLANGUAGE
#include <zephyr/types.h>
#include <zephyr/linker/sections.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
/*
 * System Call Declaration macros
 *
 * These macros are used in public header files to declare system calls.
 * They generate inline functions which have different implementations
 * depending on the current compilation context:
 *
 * - Kernel-only code, or CONFIG_USERSPACE disabled, these inlines will
 *   directly call the implementation
 * - User-only code, these inlines will marshal parameters and elevate
 *   privileges
 * - Mixed or indeterminate code, these inlines will do a runtime check
 *   to determine what course of action is needed.
 *
 * All system calls require a verifier function and an implementation
 * function.  These must follow a naming convention. For a system call
 * named k_foo():
 *
 * - The handler function will be named z_vrfy_k_foo(). Handler
 *   functions have the same type signature as the wrapped call,
 *   verify arguments passed up from userspace, and call the
 *   implementation function. See documentation for that typedef for
 *   more information.  - The implementation function will be named
 *   z_impl_k_foo(). This is the actual implementation of the system
 *   call.
 */
 
typedef uintptr_t (*_k_syscall_handler_t)(uintptr_t arg1, uintptr_t arg2,
                                          uintptr_t arg3, uintptr_t arg4,
                                          uintptr_t arg5, uintptr_t arg6,
                                          void *ssf);
 
/* True if a syscall function must trap to the kernel, usually a
 * compile-time decision.
 */
static ALWAYS_INLINE bool z_syscall_trap(void)
{
        bool ret = false;
#ifdef CONFIG_USERSPACE
#if defined(__ZEPHYR_SUPERVISOR__)
        ret = false;
#elif defined(__ZEPHYR_USER__)
        ret = true;
#else
        ret = arch_is_user_context();
#endif
#endif
        return ret;
}
 
__pinned_func
static inline bool k_is_user_context(void)
{
#ifdef CONFIG_USERSPACE
        return arch_is_user_context();
#else
        return false;
#endif
}
static inline bool k_is_user_context(void) {…}
 
#ifdef __cplusplus
}
#endif
 
#endif /* _ASMLANGUAGE */
 
#endif