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/* Copyright (C) 2004 David Decotigny
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
USA.
*/
#ifndef _SOS_IDT_H_
#define _SOS_IDT_H_
/**
* @file idt.h
*
* Manage the x86 Interrupt Descriptor Table, the table which maps the
* hardware interrupt lines, hardware exceptions, and software
* interrupts, to software routines. We only define "interrupt gate"
* IDT entries. Don't use it directly; refer instead to interrupt.c,
* exceptions.c and syscall.c.
*
* @see Intel x86 doc, Vol 3, chapter 5
*/
#include <sos/errno.h>
#include <sos/types.h>
/* Mapping of the CPU exceptions in the IDT (imposed by Intel
standards) */
#define SOS_EXCEPT_BASE 0
#define SOS_EXCEPT_NUM 32
#define SOS_EXCEPT_MAX (SOS_HWEXCEPT_BASE + SOS_HWEXCEPT_NUM - 1)
/* Mapping of the IRQ lines in the IDT */
#define SOS_IRQ_BASE 32
#define SOS_IRQ_NUM 16
#define SOS_IRQ_MAX (SOS_IRQ_BASE + SOS_IRQ_NUM - 1)
/**
* Number of IDT entries.
*
* @note Must be large enough to map the hw interrupts, the exceptions
* (=> total is 48 entries), and the syscall(s). Since our syscall
* will be 0x42, it must be >= 0x43. Intel doc limits this to 256
* entries, we use this limit.
*/
#define SOS_IDTE_NUM 256 /* 0x100 */
/** Initialization routine: all the IDT entries (or "IDTE") are marked
"not present". */
sos_ret_t sos_idt_subsystem_setup(void);
/**
* Enable the IDT entry if handler_address != NULL, with the given
* lowest_priviledge.\ Disable the IDT entry when handler_address ==
* NULL (the lowest_priviledge parameter is then ignored). Intel doc
* says that there must not be more than 256 entries.
*
* @note IRQ Unsafe
*/
sos_ret_t sos_idt_set_handler(int index,
sos_vaddr_t handler_address,
int lowest_priviledge /* 0..3 */);
/**
* @note IRQ Unsafe
*
* @return the handler address and DPL in the 2nd and 3rd
* parameters
*/
sos_ret_t sos_idt_get_handler(int index,
sos_vaddr_t *handler_address,
int *lowest_priviledge);
#endif /* _SOS_IDT_H_ */
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