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add support of nonpreemptive multitasking and additional comments

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This commit is contained in:
Stefan Lankes 2013-11-19 23:11:53 +01:00
parent fc33e338a4
commit 67926d7c65
20 changed files with 1003 additions and 99 deletions
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2
Makefile.example
View file

@ -1,7 +1,7 @@
TOPDIR = $(shell pwd)
ARCH = x86
NAME = eduos
KERNDIRS = libkern kernel arch/$(ARCH)/kernel
KERNDIRS = libkern kernel mm arch/$(ARCH)/kernel
SUBDIRS = $(KERNDIRS)
# Set your own cross compiler tool chain prefix here

36
arch/x86/include/asm/processor.h
View file

@ -81,6 +81,42 @@ inline static void rmb(void) { asm volatile("lfence" ::: "memory"); }
/// Force strict CPU ordering, serializes store operations.
inline static void wmb(void) { asm volatile("sfence" ::: "memory"); }
/** @brief search the first most significant bit
*
* @param i source operand
* @return
* - first bit, which is set in the source operand
* - invalid value, if not bit ist set
*/
static inline size_t msb(size_t i)
{
size_t ret;
if (!i)
return (sizeof(size_t)*8);
asm volatile ("bsr %1, %0" : "=r"(ret) : "r"(i) : "cc");
return ret;
}
/** @brief search the least significant bit
*
* @param i source operand
* @return
* - first bit, which is set in the source operand
* - invalid value, if not bit ist set
*/
static inline size_t lsb(size_t i)
{
size_t ret;
if (!i)
return (sizeof(size_t)*8);
asm volatile ("bsf %1, %0" : "=r"(ret) : "r"(i) : "cc");
return ret;
}
/// A one-instruction-do-nothing
#define NOP1 asm volatile ("nop")
/// A two-instruction-do-nothing

93
arch/x86/include/asm/stddef.h
View file

@ -40,29 +40,15 @@
extern "C" {
#endif
#if __SIZEOF_POINTER__ == 4
#define CONFIG_X86_32
/// A popular type for addresses
/// This type is used to represent the size of an object.
typedef unsigned long size_t;
/// Pointer differences
typedef long ptrdiff_t;
#ifdef __KERNEL__
/// It is similar to size_t, but must be a signed type.
typedef long ssize_t;
/// The type represents an offset and is similar to size_t, but must be a signed type.
typedef long off_t;
#endif
#elif __SIZEOF_POINTER__ == 8
#define CONFIG_X86_64
// A popular type for addresses
typedef unsigned long long size_t;
/// Pointer differences
typedef long long ptrdiff_t;
#ifdef __KERNEL__
typedef long long ssize_t;
typedef long long off_t;
#endif
#else
#error unsupported architecture
#endif
/// Unsigned 64 bit integer
typedef unsigned long long uint64_t;
@ -83,22 +69,8 @@ typedef char int8_t;
/// 16 bit wide char type
typedef unsigned short wchar_t;
#ifndef _WINT_T
#define _WINT_T
typedef unsigned int wint_t;
#endif
/** @brief This defines what the stack looks like after an ISR was called.
*
* All the interrupt handler routines use this type for their only parameter.
* Note: Our kernel doesn't use the GS and FS registers.
*/
/// This defines what the stack looks like after the task context is saved.
struct state {
#ifdef CONFIG_X86_32
// ds register
uint32_t ds;
// es register
uint32_t es;
/// EDI register
uint32_t edi;
/// ESI register
@ -116,61 +88,10 @@ struct state {
/// EAX register
uint32_t eax; /* pushed by 'pusha' */
/// Interrupt number
uint32_t int_no;
// pushed by the processor automatically
uint32_t error;
uint32_t eip;
uint32_t cs;
// state of the controll register
uint32_t eflags;
uint32_t useresp;
uint32_t ss;
#elif defined(CONFIG_X86_64)
/// R15 register
uint64_t r15;
/// R14 register
uint64_t r14;
/// R13 register
uint64_t r13;
/// R12 register
uint64_t r12;
/// R11 register
uint64_t r11;
/// R10 register
uint64_t r10;
/// R9 register
uint64_t r9;
/// R8 register
uint64_t r8;
/// RDI register
uint64_t rdi;
/// RSI register
uint64_t rsi;
/// RBP register
uint64_t rbp;
/// (pseudo) RSP register
uint64_t rsp;
/// RBX register
uint64_t rbx;
/// RDX register
uint64_t rdx;
/// RCX register
uint64_t rcx;
/// RAX register
uint64_t rax;
/// Interrupt number
uint64_t int_no;
// pushed by the processor automatically
uint64_t error;
uint64_t rip;
uint64_t cs;
uint64_t rflags;
uint64_t userrsp;
uint64_t ss;
#endif
/// state of instruction pointer
uint32_t eip;
};
#ifdef __cplusplus

68
arch/x86/include/asm/tasks.h Normal file
View file

@ -0,0 +1,68 @@
/*
* Copyright (c) 2010, Stefan Lankes, RWTH Aachen University
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* @author Stefan Lankes
* @file arch/x86/include/asm/tasks.h
* @brief Task related structure definitions
*
* This file contains the task_t structure definition
* and task state define constants
*/
#ifndef __ASM_TASKS_H__
#define __ASM_TASKS_H__
#include <eduos/stddef.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief Switch to current task
*
* @param stack Pointer to the old stack pointer
*/
void switch_context(size_t** stack);
/** @brief Setup a default frame for a new task
*
* @param task Pointer to the task structure
* @param ep The entry point for code execution
* @param arg Arguments list pointer for the task's stack
* @return
* - 0 on success
* - -EINVAL (-22) on failure
*/
int create_default_frame(task_t* task, entry_point_t ep, void* arg);
#ifdef __cplusplus
}
#endif
#endif

51
arch/x86/include/asm/tasks_types.h Normal file
View file

@ -0,0 +1,51 @@
/*
* Copyright (c) 2010, Stefan Lankes, RWTH Aachen University
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* @author Stefan Lankes
* @file arch/x86/include/asm/tasks_types.h
* @brief Task related structure definitions
*
* This file contains the task_t structure definition
* and task state define constants
*/
#ifndef __ASM_TASKS_TYPES_H__
#define __ASM_TASKS_TYPES_H__
#include <eduos/stddef.h>
#include <asm/processor.h>
#ifdef __cplusplus
extern "C" {
#endif
#ifdef __cplusplus
}
#endif
#endif

2
arch/x86/kernel/Makefile
View file

@ -1,4 +1,4 @@
C_source := multiboot.c vga.c
C_source := tasks.c multiboot.c vga.c
ASM_source := entry.asm string32.asm
MODULE := arch_x86_kernel

23
arch/x86/kernel/entry.asm
View file

@ -82,11 +82,34 @@ cpu_init:
mov cr4, eax
ret
extern get_current_stack
extern finish_task_switch
global switch_context
ALIGN 4
switch_context:
mov eax, [esp+4] ; on the stack is already the address to store the old esp
pushf ; push controll register
pusha ; push all general purpose registers...
mov [eax], esp ; store old esp
call get_current_stack ; get new esp
xchg eax, esp
; call cleanup code
call finish_task_switch
; restore context
popa
popf
ret
; Here is the definition of our stack. Remember that a stack actually grows
; downwards, so we declare the size of the data before declaring
; the identifier 'default_stack_pointer'
SECTION .data
resb 8192 ; This reserves 8KBytes of memory here
global default_stack_pointer
default_stack_pointer:
SECTION .note.GNU-stack noalloc noexec nowrite progbits

89
arch/x86/kernel/tasks.c Normal file
View file

@ -0,0 +1,89 @@
/*
* Copyright (c) 2010, Stefan Lankes, RWTH Aachen University
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <eduos/stdio.h>
#include <eduos/stdlib.h>
#include <eduos/string.h>
#include <eduos/tasks.h>
#include <eduos/errno.h>
#include <eduos/processor.h>
size_t* get_current_stack(void)
{
task_t* curr_task = current_task;
return curr_task->last_stack_pointer;
}
int create_default_frame(task_t* task, entry_point_t ep, void* arg)
{
size_t *stack;
struct state *stptr;
size_t state_size;
if (BUILTIN_EXPECT(!task, 0))
return -EINVAL;
if (BUILTIN_EXPECT(!task->stack, 0))
return -EINVAL;
memset(task->stack, 0xCD, KERNEL_STACK_SIZE);
/* The difference between setting up a task for SW-task-switching
* and not for HW-task-switching is setting up a stack and not a TSS.
* This is the stack which will be activated and popped off for iret later.
*/
stack = (size_t*) (task->stack + KERNEL_STACK_SIZE - 16); // => stack is 16byte aligned
/* Only marker for debugging purposes, ... */
*stack-- = 0xDEADBEEF;
/* the first-function-to-be-called's arguments, ... */
*stack-- = (size_t) arg;
/* and the "caller" we shall return to.
* This procedure cleans the task after exit. */
*stack = (size_t) leave_kernel_task;
/* Next bunch on the stack is the initial register state.
* The stack must look like the stack of a task which was
* scheduled away previously. */
state_size = sizeof(struct state);
stack = (size_t*) ((size_t) stack - state_size);
stptr = (struct state *) stack;
memset(stptr, 0x00, state_size);
stptr->esp = (size_t)stack + state_size;
stptr->eip = (size_t)ep;
stptr->eflags = 0x1202;
/* Set the task's stack pointer entry to the stack we have crafted right now. */
task->last_stack_pointer = (size_t*)stack;
return 0;
}

3
include/eduos/config.h.example
View file

@ -33,7 +33,10 @@ extern "C" {
#endif
#define EDUOS_VERSION "0.1"
#define MAX_TASKS 16
#define VIDEO_MEM_ADDR 0xB8000 // the video memora address
#define CACHE_LINE 64
#define KERNEL_STACK_SIZE (8*1024)
#define BYTE_ORDER LITTLE_ENDIAN

180
include/eduos/errno.h Normal file
View file

@ -0,0 +1,180 @@
/**
* @author Stefan Lankes
* @file include/eduos/errno.h
* @brief Error number define constants
*
* This file just contains the full list of error numbers which can
* be returned somewhere. In principle, we use the same error codes
* than newlib.
*/
#ifndef __ERRNO_H__
#define __ERRNO_H__
#include <eduos/config.h>
#include <asm/stddef.h>
#ifdef __cplusplus
extern "C" {
#endif
#define EPERM 1 /* Not super-user */
#define ENOENT 2 /* No such file or directory */
#define ESRCH 3 /* No such process */
#define EINTR 4 /* Interrupted system call */
#define EIO 5 /* I/O error */
#define ENXIO 6 /* No such device or address */
#define E2BIG 7 /* Arg list too long */
#define ENOEXEC 8 /* Exec format error */
#define EBADF 9 /* Bad file number */
#define ECHILD 10 /* No children */
#define EAGAIN 11 /* No more processes */
#define ENOMEM 12 /* Not enough core */
#define EACCES 13 /* Permission denied */
#define EFAULT 14 /* Bad address */
#ifdef __LINUX_ERRNO_EXTENSIONS__
#define ENOTBLK 15 /* Block device required */
#endif
#define EBUSY 16 /* Mount device busy */
#define EEXIST 17 /* File exists */
#define EXDEV 18 /* Cross-device link */
#define ENODEV 19 /* No such device */
#define ENOTDIR 20 /* Not a directory */
#define EISDIR 21 /* Is a directory */
#define EINVAL 22 /* Invalid argument */
#define ENFILE 23 /* Too many open files in system */
#define EMFILE 24 /* Too many open files */
#define ENOTTY 25 /* Not a typewriter */
#define ETXTBSY 26 /* Text file busy */
#define EFBIG 27 /* File too large */
#define ENOSPC 28 /* No space left on device */
#define ESPIPE 29 /* Illegal seek */
#define EROFS 30 /* Read only file system */
#define EMLINK 31 /* Too many links */
#define EPIPE 32 /* Broken pipe */
#define EDOM 33 /* Math arg out of domain of func */
#define ERANGE 34 /* Math result not representable */
#define ENOMSG 35 /* No message of desired type */
#define EIDRM 36 /* Identifier removed */
#ifdef __LINUX_ERRNO_EXTENSIONS__
#define ECHRNG 37 /* Channel number out of range */
#define EL2NSYNC 38 /* Level 2 not synchronized */
#define EL3HLT 39 /* Level 3 halted */
#define EL3RST 40 /* Level 3 reset */
#define ELNRNG 41 /* Link number out of range */
#define EUNATCH 42 /* Protocol driver not attached */
#define ENOCSI 43 /* No CSI structure available */
#define EL2HLT 44 /* Level 2 halted */
#endif
#define EDEADLK 45 /* Deadlock condition */
#define ENOLCK 46 /* No record locks available */
#ifdef __LINUX_ERRNO_EXTENSIONS__
#define EBADE 50 /* Invalid exchange */
#define EBADR 51 /* Invalid request descriptor */
#define EXFULL 52 /* Exchange full */
#define ENOANO 53 /* No anode */
#define EBADRQC 54 /* Invalid request code */
#define EBADSLT 55 /* Invalid slot */
#define EDEADLOCK 56 /* File locking deadlock error */
#define EBFONT 57 /* Bad font file fmt */
#endif
#define ENOSTR 60 /* Device not a stream */
#define ENODATA 61 /* No data (for no delay io) */
#define ETIME 62 /* Timer expired */
#define ENOSR 63 /* Out of streams resources */
#ifdef __LINUX_ERRNO_EXTENSIONS__
#define ENONET 64 /* Machine is not on the network */
#define ENOPKG 65 /* Package not installed */
#define EREMOTE 66 /* The object is remote */
#endif
#define ENOLINK 67 /* The link has been severed */
#ifdef __LINUX_ERRNO_EXTENSIONS__
#define EADV 68 /* Advertise error */
#define ESRMNT 69 /* Srmount error */
#define ECOMM 70 /* Communication error on send */
#endif
#define EPROTO 71 /* Protocol error */
#define EMULTIHOP 74 /* Multihop attempted */
#ifdef __LINUX_ERRNO_EXTENSIONS__
#define ELBIN 75 /* Inode is remote (not really error) */
#define EDOTDOT 76 /* Cross mount point (not really error) */
#endif
#define EBADMSG 77 /* Trying to read unreadable message */
#define EFTYPE 79 /* Inappropriate file type or format */
#ifdef __LINUX_ERRNO_EXTENSIONS__
#define ENOTUNIQ 80 /* Given log. name not unique */
#define EBADFD 81 /* f.d. invalid for this operation */
#define EREMCHG 82 /* Remote address changed */
#define ELIBACC 83 /* Can't access a needed shared lib */
#define ELIBBAD 84 /* Accessing a corrupted shared lib */
#define ELIBSCN 85 /* .lib section in a.out corrupted */
#define ELIBMAX 86 /* Attempting to link in too many libs */
#define ELIBEXEC 87 /* Attempting to exec a shared library */
#endif
#define ENOSYS 88 /* Function not implemented */
#ifdef __CYGWIN__
#define ENMFILE 89 /* No more files */
#endif
#define ENOTEMPTY 90 /* Directory not empty */
#define ENAMETOOLONG 91 /* File or path name too long */
#define ELOOP 92 /* Too many symbolic links */
#define EOPNOTSUPP 95 /* Operation not supported on transport endpoint */
#define EPFNOSUPPORT 96 /* Protocol family not supported */
#define ECONNRESET 104 /* Connection reset by peer */
#define ENOBUFS 105 /* No buffer space available */
#define EAFNOSUPPORT 106 /* Address family not supported by protocol family */
#define EPROTOTYPE 107 /* Protocol wrong type for socket */
#define ENOTSOCK 108 /* Socket operation on non-socket */
#define ENOPROTOOPT 109 /* Protocol not available */
#ifdef __LINUX_ERRNO_EXTENSIONS__
#define ESHUTDOWN 110 /* Can't send after socket shutdown */
#endif
#define ECONNREFUSED 111 /* Connection refused */
#define EADDRINUSE 112 /* Address already in use */
#define ECONNABORTED 113 /* Connection aborted */
#define ENETUNREACH 114 /* Network is unreachable */
#define ENETDOWN 115 /* Network interface is not configured */
#define ETIMEDOUT 116 /* Connection timed out */
#define EHOSTDOWN 117 /* Host is down */
#define EHOSTUNREACH 118 /* Host is unreachable */
#define EINPROGRESS 119 /* Connection already in progress */
#define EALREADY 120 /* Socket already connected */
#define EDESTADDRREQ 121 /* Destination address required */
#define EMSGSIZE 122 /* Message too long */
#define EPROTONOSUPPORT 123 /* Unknown protocol */
#ifdef __LINUX_ERRNO_EXTENSIONS__
#define ESOCKTNOSUPPORT 124 /* Socket type not supported */
#endif
#define EADDRNOTAVAIL 125 /* Address not available */
#define ENETRESET 126
#define EISCONN 127 /* Socket is already connected */
#define ENOTCONN 128 /* Socket is not connected */
#define ETOOMANYREFS 129
#ifdef __LINUX_ERRNO_EXTENSIONS__
#define EPROCLIM 130
#define EUSERS 131
#endif
#define EDQUOT 132
#define ESTALE 133
#define ENOTSUP 134 /* Not supported */
#ifdef __LINUX_ERRNO_EXTENSIONS__
#define ENOMEDIUM 135 /* No medium (in tape drive) */
#endif
#ifdef __CYGWIN__
#define ENOSHARE 136 /* No such host or network path */
#define ECASECLASH 137 /* Filename exists with different case */
#endif
#define EILSEQ 138
#define EOVERFLOW 139 /* Value too large for defined data type */
#define ECANCELED 140 /* Operation canceled */
#define ENOTRECOVERABLE 141 /* State not recoverable */
#define EOWNERDEAD 142 /* Previous owner died */
#ifdef __LINUX_ERRNO_EXTENSIONS__
#define ESTRPIPE 143 /* Streams pipe error */
#endif
#ifdef __cplusplus
}
#endif
#endif

14
include/eduos/stdarg.h
View file

@ -28,17 +28,27 @@
#ifndef __STDARG_H__
#define __STDARG_H__
/**
* @author Stefan Lankes
* @file include/eduos/stdarg.h
* @brief Definition of variable argument lists
*/
#ifdef __cplusplus
extern "C" {
#endif
typedef __builtin_va_list va_list;
/// Initialize a variable argument list
#define va_start __builtin_va_start
/// Retrieve next argument
#define va_arg __builtin_va_arg
#define va_end __builtin_va_end
/// End using variable argument list
#define va_end __builtin_va_end
/// copies the (previously initialized) variable argument list
#define va_copy __builtin_va_copy
#ifdef __cplusplus
}
#endif

18
include/eduos/stddef.h
View file

@ -28,6 +28,12 @@
#ifndef __STDDEF_H__
#define __STDDEF_H__
/**
* @author Stefan Lankes
* @file include/eduos/stddef.h
* @brief Definition of basic data types
*/
#include <eduos/config.h>
#include <asm/stddef.h>
@ -37,12 +43,12 @@ extern "C" {
#define NULL ((void*) 0)
/*
* macros, which are later used to determine the core id
* and their "private" data
*/
#define per_core(name) name
#define CORE_ID 0
/// represents a task identifier
typedef unsigned int tid_t;
struct task;
/// pointer to the current (running) task
extern struct task* current_task;
#ifdef __cplusplus
}

6
include/eduos/stdlib.h
View file

@ -44,6 +44,12 @@
extern "C" {
#endif
/** @brief Create a new stack for a new task
*
* @return start address of the new stack
*/
void* create_stack(tid_t id);
#ifdef __cplusplus
}
#endif

6
include/eduos/string.h
View file

@ -28,6 +28,12 @@
#ifndef __STRING_H__
#define __STRING_H__
/**
* @author Stefan Lankes
* @file include/eduos/string.h
* @brief Definition of basic string and memory opeations
*/
#include <eduos/stddef.h>
#include <asm/string.h>

84
include/eduos/tasks.h Normal file
View file

@ -0,0 +1,84 @@
/*
* Copyright (c) 2010, Stefan Lankes, RWTH Aachen University
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* @author Stefan Lankes
* @file include/eduos/tasks.h
* @brief Task related
*
* Create and leave tasks or fork them.
*/
#ifndef __TASKS_H__
#define __TASKS_H__
#include <eduos/stddef.h>
#include <eduos/tasks_types.h>
#include <asm/tasks.h>
#ifdef __cplusplus
extern "C" {
#endif
/** @brief Initialize the multitasking subsystem
*
* This procedure sets the current task to the
* current "task" (there are no tasks, yet) and that was it.
*
* @return
* - 0 on success
* - -ENOMEM (-12) on failure
*/
int multitasking_init(void);
/** @brief create a kernel task.
*
* @param id The value behind this pointer will be set to the new task's id
* @param ep Pointer to the entry function for the new task
* @param args Arguments the task shall start with
* @param prio Desired priority of the new kernel task
*
* @return
* - 0 on success
* - -EINVAL (-22) on failure
*/
int create_kernel_task(tid_t* id, entry_point_t ep, void* args, uint8_t prio);
/** @brief Call to rescheduling
*
* This is a purely assembled procedure for rescheduling
*/
void reschedule(void);
/** @brief This function shall be called by leaving kernel level tasks */
void NORETURN leave_kernel_task(void);
#ifdef __cplusplus
}
#endif
#endif

104
include/eduos/tasks_types.h Normal file
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@ -0,0 +1,104 @@
/*
* Copyright (c) 2010, Stefan Lankes, RWTH Aachen University
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* @author Stefan Lankes
* @file include/eduos/tasks_types.h
* @brief Task related structure definitions
*
* This file contains the task_t structure definition
* and task state define constants
*/
#ifndef __TASKS_TYPES_H__
#define __TASKS_TYPES_H__
#include <eduos/stddef.h>
#include <asm/tasks_types.h>
#ifdef __cplusplus
extern "C" {
#endif
#define TASK_INVALID 0
#define TASK_READY 1
#define TASK_RUNNING 2
#define TASK_BLOCKED 3
#define TASK_FINISHED 4
#define TASK_IDLE 5
#define MAX_PRIO 31
#define REALTIME_PRIO 31
#define HIGH_PRIO 16
#define NORMAL_PRIO 8
#define LOW_PRIO 1
#define IDLE_PRIO 0
typedef int (*entry_point_t)(void*);
/** @brief Represents a the process control block */
typedef struct task {
/// Task id = position in the task table
tid_t id;
/// Task status (INVALID, READY, RUNNING, ...)
uint32_t status;
/// copy of the stack pointer before a context switch
size_t* last_stack_pointer;
/// start address of the stack
void* stack;
/// Task priority
uint8_t prio;
/// next task in the queue
struct task* next;
/// previous task in the queue
struct task* prev;
} task_t;
typedef struct {
task_t* first;
task_t* last;
} task_list_t;
/** @brief Represents a queue for all runable tasks */
typedef struct {
/// idle task
task_t* idle __attribute__ ((aligned (CACHE_LINE)));
/// previous task
task_t* old_task;
/// total number of tasks in the queue
uint32_t nr_tasks;
/// indicates the used priority queues
uint32_t prio_bitmap;
/// a queue for each priority
task_list_t queue[MAX_PRIO];
} runqueue_t;
#ifdef __cplusplus
}
#endif
#endif

2
kernel/Makefile
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@ -1,4 +1,4 @@
C_source := main.c
C_source := main.c tasks.c
MODULE := kernel
include $(TOPDIR)/Makefile.inc

24
kernel/main.c
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@ -28,7 +28,9 @@
#include <eduos/stddef.h>
#include <eduos/stdio.h>
#include <eduos/string.h>
#include <eduos/tasks.h>
#include <eduos/processor.h>
#include <eduos/tasks.h>
/*
* Note that linker symbols are not variables, they have no memory allocated for
@ -41,24 +43,42 @@ extern const void bss_end;
extern char __BUILD_DATE;
extern char __BUILD_TIME;
static int foo(void* arg)
{
int i = 0;
for(i=0; i<5; i++) {
kprintf("hello from %s\n", (char*) arg);
reschedule();
}
return 0;
}
static int eduos_init(void)
{
// initialize .bss section
memset((void*)&bss_start, 0x00, ((size_t) &bss_end - (size_t) &bss_start));
koutput_init();
multitasking_init();
return 0;
}
int main(void)
{
tid_t id1;
tid_t id2;
eduos_init();
kprintf("This is eduOS %s Build %u, %u\n", EDUOS_VERSION, &__BUILD_DATE, &__BUILD_TIME);
kprintf("Kernel starts at %p and ends at %p\n", &kernel_start, &kernel_end);
kprintf("\nHello World!\n");
create_kernel_task(&id1, foo, "foo1", NORMAL_PRIO);
create_kernel_task(&id2, foo, "foo2", NORMAL_PRIO);
reschedule();
while(1) {
NOP8;
}

254
kernel/tasks.c Normal file
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@ -0,0 +1,254 @@
/*
* Copyright (c) 2010, Stefan Lankes, RWTH Aachen University
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <eduos/stddef.h>
#include <eduos/stdlib.h>
#include <eduos/stdio.h>
#include <eduos/tasks.h>
#include <eduos/tasks_types.h>
#include <eduos/errno.h>
extern void* default_stack_pointer;
/** @brief Array of task structures (aka PCB)
*
* A task's id will be its position in this array.
*/
static task_t task_table[MAX_TASKS] = { \
[0] = {0, TASK_IDLE, NULL, NULL, 0, NULL, NULL}, \
[1 ... MAX_TASKS-1] = {0, TASK_INVALID, NULL, NULL, 0, NULL, NULL}};
static runqueue_t runqueue = { task_table+0, NULL, 0, 0, {[0 ... MAX_PRIO-1] = {NULL, NULL}}};
task_t* current_task = task_table+0;
/** @brief helper function for the assembly code to determine the current task
* @return Pointer to the task_t structure of current task
*/
task_t* get_current_task(void)
{
return current_task;
}
/** @brief determines the highest priority of the all runable task
* @return Highest priority
*/
uint32_t get_highest_priority(void)
{
return msb(runqueue.prio_bitmap);
}
int multitasking_init(void)
{
if (BUILTIN_EXPECT(task_table[0].status != TASK_IDLE, 0)) {
kputs("Task 0 is not an idle task\n");
return -ENOMEM;
}
task_table[0].prio = IDLE_PRIO;
task_table[0].stack = default_stack_pointer - 8192;
return 0;
}
void finish_task_switch(void)
{
task_t* old;
uint8_t prio;
if ((old = runqueue.old_task) != NULL) {
if (old->status == TASK_INVALID) {
old->stack = NULL;
old->last_stack_pointer = NULL;
runqueue.old_task = NULL;
} else {
prio = old->prio;
if (!runqueue.queue[prio-1].first) {
old->next = old->prev = NULL;
runqueue.queue[prio-1].first = runqueue.queue[prio-1].last = old;
} else {
old->next = NULL;
old->prev = runqueue.queue[prio-1].last;
runqueue.queue[prio-1].last->next = old;
runqueue.queue[prio-1].last = old;
}
runqueue.old_task = NULL;
runqueue.prio_bitmap |= (1 << prio);
}
}
}
/** @brief A procedure to be called by
* procedures which are called by exiting tasks. */
static void NORETURN do_exit(int arg)
{
task_t* curr_task = current_task;
kprintf("Terminate task: %u, return value %d\n", curr_task->id, arg);
curr_task->status = TASK_FINISHED;
reschedule();
kprintf("Kernel panic: scheduler found no valid task\n");
while(1) {
NOP8;
}
}
/** @brief A procedure to be called by kernel tasks */
void NORETURN leave_kernel_task(void) {
int result;
result = 0; //get_return_value();
do_exit(result);
}
/** @brief Create a task with a specific entry point
*
* @param id Pointer to a tid_t struct were the id shall be set
* @param ep Pointer to the function the task shall start with
* @param arg Arguments list
* @param prio Desired priority of the new task
* @param core_id Start the new task on the core with this id
*
* @return
* - 0 on success
* - -ENOMEM (-12) or -EINVAL (-22) on failure
*/
static int create_task(tid_t* id, entry_point_t ep, void* arg, uint8_t prio)
{
int ret = -ENOMEM;
uint32_t i;
if (BUILTIN_EXPECT(!ep, 0))
return -EINVAL;
if (BUILTIN_EXPECT(prio == IDLE_PRIO, 0))
return -EINVAL;
if (BUILTIN_EXPECT(prio > MAX_PRIO, 0))
return -EINVAL;
for(i=0; i<MAX_TASKS; i++) {
if (task_table[i].status == TASK_INVALID) {
task_table[i].id = i;
task_table[i].status = TASK_READY;
task_table[i].last_stack_pointer = NULL;
task_table[i].stack = create_stack(i);
task_table[i].prio = prio;
if (id)
*id = i;
ret = create_default_frame(task_table+i, ep, arg);
// add task in the runqueue
runqueue.prio_bitmap |= (1 << prio);
runqueue.nr_tasks++;
if (!runqueue.queue[prio-1].first) {
task_table[i].next = task_table[i].prev = NULL;
runqueue.queue[prio-1].first = task_table+i;
runqueue.queue[prio-1].last = task_table+i;
} else {
task_table[i].prev = runqueue.queue[prio-1].last;
task_table[i].next = NULL;
runqueue.queue[prio-1].last->next = task_table+i;
runqueue.queue[prio-1].last = task_table+i;
}
break;
}
}
return ret;
}
int create_kernel_task(tid_t* id, entry_point_t ep, void* args, uint8_t prio)
{
if (prio > MAX_PRIO)
prio = NORMAL_PRIO;
return create_task(id, ep, args, prio);
}
size_t** scheduler(void)
{
task_t* orig_task;
task_t* curr_task;
uint32_t prio;
orig_task = curr_task = current_task;
/* signalizes that this task could be reused */
if (curr_task->status == TASK_FINISHED) {
curr_task->status = TASK_INVALID;
runqueue.old_task = curr_task;
} else runqueue.old_task = NULL; // reset old task
prio = msb(runqueue.prio_bitmap); // determines highest priority
if (prio >= sizeof(size_t)*8) {
if ((curr_task->status == TASK_RUNNING) || (curr_task->status == TASK_IDLE))
goto get_task_out;
curr_task = current_task = runqueue.idle;
} else {
// Does the current task have an higher priority? => no task switch
if ((curr_task->prio > prio) && (curr_task->status == TASK_RUNNING))
goto get_task_out;
if (curr_task->status == TASK_RUNNING) {
curr_task->status = TASK_READY;
runqueue.old_task = curr_task;
}
curr_task = current_task = runqueue.queue[prio-1].first;
if (BUILTIN_EXPECT(curr_task->status == TASK_INVALID, 0)) {
kprintf("Upps!!!!!!! Got invalid task %d, orig task %d\n", curr_task->id, orig_task->id);
}
curr_task->status = TASK_RUNNING;
// remove new task from queue
runqueue.queue[prio-1].first = curr_task->next;
if (!curr_task->next) {
runqueue.queue[prio-1].last = NULL;
runqueue.prio_bitmap &= ~(1 << prio);
}
curr_task->next = curr_task->prev = NULL;
}
get_task_out:
if (curr_task != orig_task) {
//kprintf("schedule from %u to %u with prio %u\n", orig_task->id, curr_task->id, (uint32_t)curr_task->prio);
return (size_t**) &(orig_task->last_stack_pointer);
}
return NULL;
}
void reschedule(void)
{
size_t** stack;
if ((stack = scheduler()))
switch_context(stack);
}

43
mm/memory.c Normal file
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@ -0,0 +1,43 @@
/*
* Copyright (c) 2010, Stefan Lankes, RWTH Aachen University
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <eduos/stddef.h>
#include <eduos/stdlib.h>
static char stack[MAX_TASKS-1][KERNEL_STACK_SIZE];
void* create_stack(tid_t id)
{
// idle task uses stack, which is defined in entry.asm
if (BUILTIN_EXPECT(!id, 0))
return NULL;
// do we have a valid task id?
if (BUILTIN_EXPECT(id >= MAX_TASKS, 0))
return NULL;
return (void*) stack[id-1];
}