127 lines
3.7 KiB
C
127 lines
3.7 KiB
C
/* idtEnt.h - IA-32 IDT Entry code */
|
|
|
|
/*
|
|
* Copyright (c) 2012-2014, Wind River Systems, Inc.
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
/*
|
|
* DESCRIPTION
|
|
* This header file provides code for constructing an IA-32 interrupt
|
|
* descriptor.
|
|
*/
|
|
|
|
#ifndef _IDTENT_H
|
|
#define _IDTENT_H
|
|
|
|
#ifdef __cplusplus
|
|
extern"C"
|
|
{
|
|
#endif
|
|
|
|
/**
|
|
* Bitmask used to determine which exceptions result in an error code being
|
|
* pushed onto the stack. The following exception vectors push an error code:
|
|
*
|
|
* Vector Mnemonic Description
|
|
* ------ ------- ----------------------
|
|
* 8 #DF Double Fault
|
|
* 10 #TS Invalid TSS
|
|
* 11 #NP Segment Not Present
|
|
* 12 #SS Stack Segment Fault
|
|
* 13 #GP General Protection Fault
|
|
* 14 #PF Page Fault
|
|
* 17 #AC Alignment Check
|
|
*/
|
|
#define _EXC_ERROR_CODE_FAULTS 0x27d00
|
|
|
|
|
|
/*
|
|
* Interrupt Descriptor Table (IDT) entry structure
|
|
*
|
|
* (This is taken from Intel documentation, so don't try to interpret it
|
|
* too deeply.)
|
|
*/
|
|
|
|
typedef struct idtEntry {
|
|
unsigned short lowOffset;
|
|
unsigned short segmentSelector;
|
|
unsigned short reserved:5;
|
|
unsigned short intGateIndicator:8;
|
|
unsigned short descPrivLevel:2;
|
|
unsigned short present:1;
|
|
unsigned short hiOffset;
|
|
} __packed IDT_ENTRY;
|
|
|
|
/**
|
|
*
|
|
* @brief Create an IDT entry
|
|
*
|
|
* This routine creates an interrupt-gate descriptor at the location defined by
|
|
* @a pIdtEntry. The entry is created such that @a routine is invoked when an
|
|
* interrupt vector is asserted. The @a dpl argument specifies the privilege
|
|
* level for the interrupt-gate descriptor; (hardware) interrupts and exceptions
|
|
* should specify a level of 0, whereas handlers for user-mode software generated
|
|
* interrupts should specify 3.
|
|
*
|
|
* @param pIdtEntry Pointer to where the entry is be built
|
|
* @param routine Routine to call when interrupt occurs
|
|
* @param dpl Private level for interrupt descriptor
|
|
* @return N/A
|
|
*
|
|
* INTERNAL
|
|
* This is a shared routine between the IA-32 nanokernel runtime code and the
|
|
* genIdt host tool code. It is done this way to keep the two sides in sync.
|
|
*
|
|
* The runtime passes a pointer directly to the IDT entry to update whereas the
|
|
* host side simply passes a pointer to a local variable.
|
|
*
|
|
*/
|
|
static inline void _IdtEntCreate(unsigned long long *pIdtEntry,
|
|
void (*routine)(void *),
|
|
unsigned int dpl)
|
|
{
|
|
unsigned long *pIdtEntry32 = (unsigned long *)pIdtEntry;
|
|
|
|
pIdtEntry32[0] = (KERNEL_CODE_SEG_SELECTOR << 16) |
|
|
((unsigned short)(unsigned int)routine);
|
|
|
|
/*
|
|
* The constant 0x8e00 results from the following:
|
|
*
|
|
* Segment Present = 1
|
|
*
|
|
* Descriptor Privilege Level (DPL) = 0 (dpl arg will be or'ed in)
|
|
*
|
|
* Interrupt Gate Indicator = 0xE
|
|
* The _IntEnt() and _ExcEnt() stubs assume that an interrupt-gate
|
|
* descriptor is used, and thus they do not issue a 'cli' instruction
|
|
* given that the processor automatically clears the IF flag when
|
|
* accessing the interrupt/exception handler via an interrupt-gate.
|
|
*
|
|
* Size of Gate (D) = 1
|
|
*
|
|
* Reserved = 0
|
|
*/
|
|
|
|
pIdtEntry32[1] = ((unsigned int) routine & 0xffff0000) |
|
|
(0x8e00 | (dpl << 13));
|
|
}
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|
|
|
|
#endif /* _IDTENT_H */
|