minix/kernel/table.c

/* The object file of "table.c" contains most kernel data. Variables that 
 * are declared in the *.h files appear with EXTERN in front of them, as in
 *
 *    EXTERN int x;
 *
 * Normally EXTERN is defined as extern, so when they are included in another
 * file, no storage is allocated.  If EXTERN were not present, but just say,
 *
 *    int x;
 *
 * then including this file in several source files would cause 'x' to be
 * declared several times.  While some linkers accept this, others do not,
 * so they are declared extern when included normally.  However, it must be
 * declared for real somewhere.  That is done here, by redefining EXTERN as
 * the null string, so that inclusion of all *.h files in table.c actually
 * generates storage for them.  
 *
 * Various variables could not be declared EXTERN, but are declared PUBLIC
 * or PRIVATE. The reason for this is that extern variables cannot have a  
 * default initialization. If such variables are shared, they must also be
 * declared in one of the *.h files without the initialization.  Examples 
 * include 'boot_image' (this file) and 'idt' and 'gdt' (protect.c). 
 *
 * Changes:
 *    Aug 02, 2005   set privileges and minimal boot image (Jorrit N. Herder)
 *    Oct 17, 2004   updated above and tasktab comments  (Jorrit N. Herder)
 *    May 01, 2004   changed struct for system image  (Jorrit N. Herder)
 */
#define _TABLE

#include "kernel.h"
#include "proc.h"
#include "ipc.h"
#include <minix/com.h>
#include <ibm/int86.h>

/* Define stack sizes for the kernel tasks included in the system image. */
#define NO_STACK	0
#define SMALL_STACK	(128 * sizeof(char *))
#define IDL_S	SMALL_STACK	/* 3 intr, 3 temps, 4 db for Intel */
#define	HRD_S	NO_STACK	/* dummy task, uses kernel stack */
#define	TSK_S	SMALL_STACK	/* system and clock task */

/* Stack space for all the task stacks.  Declared as (char *) to align it. */
#define	TOT_STACK_SPACE	(IDL_S + HRD_S + (2 * TSK_S))
PUBLIC char *t_stack[TOT_STACK_SPACE / sizeof(char *)];
	
/* Define flags for the various process types. */
#define IDL_F 	(BILLABLE | SYS_PROC)		/* idle task */
#define TSK_F 	(SYS_PROC)			/* kernel tasks */
#define SRV_F 	(BILLABLE | PREEMPTIBLE | SYS_PROC)	/* system services */
#define USR_F	(PREEMPTIBLE | BILLABLE)	/* user processes */

/* Define system call traps for the various process types. These call masks
 * determine what system call traps a process is allowed to make.
 */
#define TSK_T	(1 << RECEIVE)			/* clock and system */
#define SRV_T	(~0)				/* system services */
#define USR_T   ((1 << SENDREC) | (1 << ECHO))	/* user processes */

/* Send masks determine to whom processes can send messages or notifications. 
 * The values here are used for the processes in the boot image. We rely on 
 * the initialization code in main() to match the s_nr_to_id() mapping for the
 * processes in the boot image, so that the send mask that is defined here 
 * can be directly copied onto map[0] of the actual send mask. Privilege
 * structure 0 is shared by user processes. 
 */
#define s(n)		(1 << s_nr_to_id(n))
#define SRV_M	(~0)
#define SYS_M	(~0)
#define USR_M	(s(PM_PROC_NR) | s(FS_PROC_NR) | s(SM_PROC_NR))
#define DRV_M	(USR_M | s(SYSTEM) | s(CLOCK) | s(LOG_PROC_NR) | s(TTY_PROC_NR))

/* Define kernel calls that processes are allowed to make. This is not looking
 * very nice, but we need to define the access rights on a per call basis. 
 * Note that the system services manager has all bits on, because it should
 * be allowed to distribute rights to services that it starts. 
 */
#define c(n)	(1 << ((n)-KERNEL_CALL))
#define SM_C	~0	
#define PM_C	~(c(SYS_DEVIO) | c(SYS_SDEVIO) | c(SYS_VDEVIO) \
    | c(SYS_IRQCTL) | c(SYS_INT86))
#define FS_C	(c(SYS_KILL) | c(SYS_VIRCOPY) | c(SYS_VIRVCOPY) | c(SYS_UMAP) \
    | c(SYS_GETINFO) | c(SYS_EXIT) | c(SYS_TIMES) | c(SYS_SETALARM))
#define DRV_C	(FS_C | c(SYS_SEGCTL) | c(SYS_IRQCTL) | c(SYS_INT86) \
    | c(SYS_DEVIO) | c(SYS_VDEVIO) | c(SYS_SDEVIO) | c(SYS_PHYSCOPY) | c(SYS_PHYSVCOPY))

/* The system image table lists all programs that are part of the boot image. 
 * The order of the entries here MUST agree with the order of the programs
 * in the boot image and all kernel tasks must come first.
 * Each entry provides the process number, flags, quantum size (qs), scheduling 
 * queue, allowed traps, ipc mask, and a name for the process table. The 
 * initial program counter and stack size is also provided for kernel tasks.
 */
PUBLIC struct boot_image image[] = {
/* process nr,   pc, flags, qs,  queue, stack, traps, ipcto, call,  name */ 
 { IDLE,  idle_task, IDL_F, 32, IDLE_Q, IDL_S,     0,     0,     0, "IDLE"  },
 { CLOCK,clock_task, TSK_F,  0, TASK_Q, TSK_S, TSK_T,     0,     0, "CLOCK" },
 { SYSTEM, sys_task, TSK_F,  0, TASK_Q, TSK_S, TSK_T,     0,     0, "SYSTEM"},
 { HARDWARE,      0, TSK_F,  0, TASK_Q, HRD_S,     0,     0,     0, "KERNEL"},
 { PM_PROC_NR,    0, SRV_F, 16,      3, 0,     SRV_T, SRV_M,  PM_C, "pm"    },
 { FS_PROC_NR,    0, SRV_F, 16,      4, 0,     SRV_T, SRV_M,  FS_C, "fs"    },
 { SM_PROC_NR,    0, SRV_F, 16,      3, 0,     SRV_T, SYS_M,  SM_C, "sm"    },
 { TTY_PROC_NR,   0, SRV_F, 16,      1, 0,     SRV_T, SYS_M, DRV_C, "tty"   },
 { MEM_PROC_NR,   0, SRV_F, 16,      2, 0,     SRV_T, DRV_M, DRV_C, "memory"},
 { LOG_PROC_NR,   0, SRV_F, 16,      2, 0,     SRV_T, SYS_M, DRV_C, "log"   },
 { DRVR_PROC_NR,  0, SRV_F, 16,      2, 0,     SRV_T, SYS_M, DRV_C, "driver"},
 { INIT_PROC_NR,  0, USR_F,  8, USER_Q, 0,     USR_T, USR_M,     0, "init"  },
};

/* Verify the size of the system image table at compile time. Also verify that 
 * the first chunk of the ipc mask has enough bits to accommodate the processes
 * in the image.  
 * If a problem is detected, the size of the 'dummy' array will be negative, 
 * causing a compile time error. Note that no space is actually allocated 
 * because 'dummy' is declared extern.
 */
extern int dummy[(NR_BOOT_PROCS==sizeof(image)/sizeof(struct boot_image))?1:-1];
extern int dummy[(BITCHUNK_BITS > NR_BOOT_PROCS - 1) ? 1 : -1];