aos/include/barrelfish_kpi/syscalls.h
Daniel Schwyn 6d444bf552 Main handout
Signed-off-by: Daniel Schwyn <daniel.schwyn@inf.ethz.ch>
2022-03-03 14:57:51 +01:00

105 lines
4.2 KiB
C

/**
* \file
* \brief System call numbers.
*/
/*
* Copyright (c) 2007, 2008, 2009, 2010, ETH Zurich.
* All rights reserved.
*
* This file is distributed under the terms in the attached LICENSE file.
* If you do not find this file, copies can be found by writing to:
* ETH Zurich D-INFK, Universitaetstrasse 6, CH-8092 Zurich. Attn: Systems Group.
*/
#ifndef BARRELFISH_SYSCALLS_H
#define BARRELFISH_SYSCALLS_H
#ifndef __ASSEMBLER__
#include <stdint.h>
#include <errors/errno.h>
/// return type from a system call: two words
struct sysret {
errval_t error;
uintptr_t value;
};
/// Macro used for constructing return values from single-value syscalls
#define SYSRET(x) (struct sysret){ /*error*/ x, /*value*/ 0 }
#endif // __ASSEMBLER__
/*
* These are the system call ordinals. Please keep the space contiguous
* as far as possible and make sure SYSCALL_COUNT is the number of system
* calls. Lower layers may build direct-mapped syscall tables and so
* compactness is a virtue.
*/
/* Proper Barrelfish system calls */
#define SYSCALL_INVOKE 0 ///< Invoke a cap
#define SYSCALL_YIELD 1 ///< Yield the CPU
#define SYSCALL_LRPC 2 ///< Fast LRPC
/* Debug/Benchmarking system calls */
#define SYSCALL_DEBUG 3 ///< Benchmarking and debug syscalls
#define SYSCALL_REBOOT 4 ///< Reboot the machine
#define SYSCALL_NOP 5 ///< No operation
#define SYSCALL_PRINT 6 ///< Write to console
#define SYSCALL_GETCHAR 7 ///< Read from console
/* Architecture-specific syscalls - X86
* FIXME: shouldn't these be in an arch-specific header? -AB */
#define SYSCALL_X86_RELOAD_LDT 9 ///< Reload the LDT register (x86_64)
#define SYSCALL_SUSPEND 10 ///< Suspend the CPU
/* Architecture-specific syscalls - ARMv7 */
#define SYSCALL_ARMv7_CACHE_CLEAN 8 ///< Clean (write back) by VA
#define SYSCALL_ARMv7_CACHE_INVAL 9 ///< Invalidate (discard) by VA
#define SYSCALL_COUNT 10 ///< Number of syscalls [0..SYSCALL_COUNT - 1]
/*
* To understand system calls it might be helpful to know that there
* are four different levels of abstraction with multiplexing
* performed at three of them (compare with Tennenhouse: Layered
* Multiplexing Considered Harmful).
*
* At the bottom two levels of abstraction are the system call number
* as defined in this file. This is one point of multiplexing and two
* levels of abstraction; the second one comes about because the
* system calls defined here use non primitive C types such as
* "struct sysret" which have to be converted and dealt with by a
* level of abstraction to deal with the encoding used over the
* protection boundary. For example, on some architectures
* structures, including output structures, are passed by reference in
* the argument list. Therefore below the C abstraction of the system
* call there must be a translation to an abstraction which can cross
* the protection boundary.
*
* Above this is the invoke system call. It deals with two different
* ways of doing additional multiplexing, based on the type of the
* capability being invoked, and the command being invoked on the
* capability. This defines which kernel system call implementation
* is to be run. An aspect of this is that the arguments to the
* intended kernel code have to multiplexed up in user space onto the
* invoke system call and demultiplexed by the kernel, thus preventing
* direct dispatch to the intended implementation.
*
* Above this is the endpoint invocation in which the above system
* invocation system call is performed and demultiplexed, but the
* target capability is a special type in which the implementation
* code being called is not in the kernel; in this the arguments to
* the desired functionality must be marshalled in such a way that
* they can be delivered to the desired domain instead of the kernel.
*
* Knowing this will help the reader understand the various different
* marshalling and unmarshalling code found variously in
* monitor_invocations.h, invocations.h, syscalls.c, syscall_arch.h,
* syscall.c and related assembler.
*/
#endif // BARRELFISH_SYSCALLS_H