minix/kernel/table.c
Cristiano Giuffrida f4574783dc Rewrite of boot process
KERNEL CHANGES:
- The kernel only knows about privileges of kernel tasks and the root system
process (now RS).
- Kernel tasks and the root system process are the only processes that are made
schedulable by the kernel at startup. All the other processes in the boot image
don't get their privileges set at startup and are inhibited from running by the
RTS_NO_PRIV flag.
- Removed the assumption on the ordering of processes in the boot image table.
System processes can now appear in any order in the boot image table.
- Privilege ids can now be assigned both statically or dynamically. The kernel
assigns static privilege ids to kernel tasks and the root system process. Each
id is directly derived from the process number.
- User processes now all share the static privilege id of the root user
process (now INIT).
- sys_privctl split: we have more calls now to let RS set privileges for system
processes. SYS_PRIV_ALLOW / SYS_PRIV_DISALLOW are only used to flip the
RTS_NO_PRIV flag and allow / disallow a process from running. SYS_PRIV_SET_SYS /
SYS_PRIV_SET_USER are used to set privileges for a system / user process.
- boot image table flags split: PROC_FULLVM is the only flag that has been
moved out of the privilege flags and is still maintained in the boot image
table. All the other privilege flags are out of the kernel now.

RS CHANGES:
- RS is the only user-space process who gets to run right after in-kernel
startup.
- RS uses the boot image table from the kernel and three additional boot image
info table (priv table, sys table, dev table) to complete the initialization
of the system.
- RS checks that the entries in the priv table match the entries in the boot
image table to make sure that every process in the boot image gets schedulable.
- RS only uses static privilege ids to set privileges for system services in
the boot image.
- RS includes basic memory management support to allocate the boot image buffer
dynamically during initialization. The buffer shall contain the executable
image of all the system services we would like to restart after a crash.
- First step towards decoupling between resource provisioning and resource
requirements in RS: RS must know what resources it needs to restart a process
and what resources it has currently available. This is useful to tradeoff
reliability and resource consumption. When required resources are missing, the
process cannot be restarted. In that case, in the future, a system flag will
tell RS what to do. For example, if CORE_PROC is set, RS should trigger a
system-wide panic because the system can no longer function correctly without
a core system process.

PM CHANGES:
- The process tree built at initialization time is changed to have INIT as root
with pid 0, RS child of INIT and all the system services children of RS. This
is required to make RS in control of all the system services.
- PM no longer registers labels for system services in the boot image. This is
now part of RS's initialization process.
2009-12-11 00:08:19 +00:00

89 lines
4 KiB
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:
* Nov 22, 2009 rewrite of privilege management (Cristiano Giuffrida)
* 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>
/* Define stack sizes for the kernel tasks included in the system image. */
#define NO_STACK 0
#define SMALL_STACK (1024 * 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 boot process flags. */
#define BVM_F (PROC_FULLVM) /* boot processes with VM */
/* 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, scheduling
* queue, and a name for the process table. The initial program counter and
* stack size is also provided for kernel tasks.
*
* Note: the quantum size must be positive in all cases!
*/
PUBLIC struct boot_image image[] = {
/* process nr, pc, flags, qs, queue, stack, name */
{IDLE, NULL, 0, 0, 0, IDL_S, "idle" },
{CLOCK,clock_task, 0, 8, TASK_Q, TSK_S, "clock" },
{SYSTEM, sys_task, 0, 8, TASK_Q, TSK_S, "system"},
{HARDWARE, 0, 0, 8, TASK_Q, HRD_S, "kernel"},
{PM_PROC_NR, 0, 0, 32, 4, 0, "pm" },
{FS_PROC_NR, 0, 0, 32, 5, 0, "vfs" },
{RS_PROC_NR, 0, 0, 4, 4, 0, "rs" },
{MEM_PROC_NR, 0, BVM_F, 4, 3, 0, "memory"},
{LOG_PROC_NR, 0, BVM_F, 4, 2, 0, "log" },
{TTY_PROC_NR, 0, BVM_F, 4, 1, 0, "tty" },
{DS_PROC_NR, 0, BVM_F, 4, 4, 0, "ds" },
{MFS_PROC_NR, 0, BVM_F, 32, 5, 0, "mfs" },
{VM_PROC_NR, 0, 0, 32, 2, 0, "vm" },
{INIT_PROC_NR, 0, BVM_F, 8, USER_Q, 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];