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/*
* Copyright (c) 2017, Intel Corporation
*
* SPDX-License-Identifier: Apache 2.0
*/
#ifndef _ZEPHYR_SYSCALL_H_
#define _ZEPHYR_SYSCALL_H_
#ifndef _ASMLANGUAGE
#include <zephyr/types.h>
#include <syscall_list.h>
#include <syscall_macros.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 handler function and an implementation function.
* These must follow a naming convention. For a system call named k_foo():
*
* - The handler function will be named _handler_k_foo(). Handler functions
* are always of type _k_syscall_handler_t, 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 _impl_k_foo(). This is the
* actual implementation of the system call.
*
* The basic declartion macros are as follows. System calls with 0 to 10
* parameters are supported. For a system call with N parameters, that returns
* a value and is* not implemented inline, the macro is as follows (N noted
* as {N} for clarity):
*
* K_SYSCALL_DECLARE{N}(id, name, ret, t0, p0, ... , t{N-1}, p{N-1})
* @param id System call ID, one of K_SYSCALL_* defines
* @param name Symbol name of the system call used to invoke it
* @param ret Data type of return value
* @param tX Data type of parameter X
* @param pX Name of parameter x
*
* For system calls that return no value:
*
* K_SYSCALL_DECLARE{n}_VOID(id, name, t0, p0, .... , t{N-1}, p{N-1})
*
* This is identical to above except there is no 'ret' parameter.
*
* For system calls where the implementation is an inline function, we have
*
* K_SYSCALL_DECLARE{n}_INLINE(id, name, ret, t0, p0, ... , t{N-1}, p{N-1})
* K_SYSCALL_DECLARE{n}_VOID_INLINE(id, name, t0, p0, ... , t{N-1}, p{N-1})
*
* These are used in the same way as their non-INLINE counterparts.
*
* These macros are generated by scripts/gen_syscall_header.py and can be
* found in $OUTDIR/include/generated/syscall_macros.h
*/
/**
* @typedef _k_syscall_handler_t
* @brief System call handler function type
*
* These are kernel-side skeleton functions for system calls. They are
* necessary to sanitize the arguments passed into the system call:
*
* - Any kernel object or device pointers are validated with _SYSCALL_IS_OBJ()
* - Any memory buffers passed in are checked to ensure that the calling thread
* actually has access to them
* - Many kernel calls do no sanity checking of parameters other than
* assertions. The handler must check all of these conditions using
* _SYSCALL_ASSERT()
* - If the system call has more than 6 arguments, then arg6 will be a pointer
* to some struct containing arguments 6+. The struct itself needs to be
* validated like any other buffer passed in from userspace, and its members
* individually validated (if necessary) and then passed to the real
* implementation like normal arguments
*
* Even if the system call implementation has no return value, these always
* return something, even 0, to prevent register leakage to userspace.
*
* Once everything has been validated, the real implementation will be executed.
*
* @param arg1 system call argument 1
* @param arg2 system call argument 2
* @param arg3 system call argument 3
* @param arg4 system call argument 4
* @param arg5 system call argument 5
* @param arg6 system call argument 6
* @param ssf System call stack frame pointer. Used to generate kernel oops
* via _arch_syscall_oops_at(). Contents are arch-specific.
* @return system call return value, or 0 if the system call implementation
* return void
*
*/
typedef u32_t (*_k_syscall_handler_t)(u32_t arg1, u32_t arg2, u32_t arg3,
u32_t arg4, u32_t arg5, u32_t arg6,
void *ssf);
#ifdef CONFIG_USERSPACE
/**
* Indicate whether we are currently running in user mode
*
* @return nonzero if the CPU is currently running with user permissions
*/
static inline int _arch_is_user_context(void);
/**
* Indicate whether the CPU is currently in user mode
*
* @return nonzero if the CPU is currently running with user permissions
*/
static inline int _is_user_context(void)
{
return _arch_is_user_context();
}
/*
* Helper data structures for system calls with large argument lists
*/
struct _syscall_7_args {
u32_t arg6;
u32_t arg7;
};
struct _syscall_8_args {
u32_t arg6;
u32_t arg7;
u32_t arg8;
};
struct _syscall_9_args {
u32_t arg6;
u32_t arg7;
u32_t arg8;
u32_t arg9;
};
struct _syscall_10_args {
u32_t arg6;
u32_t arg7;
u32_t arg8;
u32_t arg9;
u32_t arg10;
};
/*
* Interfaces for invoking system calls
*/
static inline u32_t _arch_syscall_invoke0(u32_t call_id);
static inline u32_t _arch_syscall_invoke1(u32_t arg1, u32_t call_id);
static inline u32_t _arch_syscall_invoke2(u32_t arg1, u32_t arg2,
u32_t call_id);
static inline u32_t _arch_syscall_invoke3(u32_t arg1, u32_t arg2, u32_t arg3,
u32_t call_id);
static inline u32_t _arch_syscall_invoke4(u32_t arg1, u32_t arg2, u32_t arg3,
u32_t arg4, u32_t call_id);
static inline u32_t _arch_syscall_invoke5(u32_t arg1, u32_t arg2, u32_t arg3,
u32_t arg4, u32_t arg5,
u32_t call_id);
static inline u32_t _arch_syscall_invoke6(u32_t arg1, u32_t arg2, u32_t arg3,
u32_t arg4, u32_t arg5, u32_t arg6,
u32_t call_id);
static inline u32_t _syscall_invoke7(u32_t arg1, u32_t arg2, u32_t arg3,
u32_t arg4, u32_t arg5, u32_t arg6,
u32_t arg7, u32_t call_id) {
struct _syscall_7_args args = {
.arg6 = arg6,
.arg7 = arg7,
};
return _arch_syscall_invoke6(arg1, arg2, arg3, arg4, arg5, (u32_t)&args,
call_id);
}
static inline u32_t _syscall_invoke8(u32_t arg1, u32_t arg2, u32_t arg3,
u32_t arg4, u32_t arg5, u32_t arg6,
u32_t arg7, u32_t arg8, u32_t call_id)
{
struct _syscall_8_args args = {
.arg6 = arg6,
.arg7 = arg7,
.arg8 = arg8,
};
return _arch_syscall_invoke6(arg1, arg2, arg3, arg4, arg5, (u32_t)&args,
call_id);
}
static inline u32_t _syscall_invoke9(u32_t arg1, u32_t arg2, u32_t arg3,
u32_t arg4, u32_t arg5, u32_t arg6,
u32_t arg7, u32_t arg8, u32_t arg9,
u32_t call_id)
{
struct _syscall_9_args args = {
.arg6 = arg6,
.arg7 = arg7,
.arg8 = arg8,
.arg9 = arg9,
};
return _arch_syscall_invoke6(arg1, arg2, arg3, arg4, arg5, (u32_t)&args,
call_id);
}
static inline u32_t _syscall_invoke10(u32_t arg1, u32_t arg2, u32_t arg3,
u32_t arg4, u32_t arg5, u32_t arg6,
u32_t arg7, u32_t arg8, u32_t arg9,
u32_t arg10, u32_t call_id)
{
struct _syscall_10_args args = {
.arg6 = arg6,
.arg7 = arg7,
.arg8 = arg8,
.arg9 = arg9,
.arg10 = arg10
};
return _arch_syscall_invoke6(arg1, arg2, arg3, arg4, arg5, (u32_t)&args,
call_id);
}
static inline u64_t _syscall_ret64_invoke0(u32_t call_id)
{
u64_t ret;
_arch_syscall_invoke1((u32_t)&ret, call_id);
return ret;
}
static inline u64_t _syscall_ret64_invoke1(u32_t arg1, u32_t call_id)
{
u64_t ret;
_arch_syscall_invoke2(arg1, (u32_t)&ret, call_id);
return ret;
}
#endif /* CONFIG_USERSPACE */
#ifdef __cplusplus
}
#endif
#endif /* _ASMLANGUAGE */
#endif