143 lines
4.7 KiB
C
143 lines
4.7 KiB
C
/* idtEnt.h - IA-32 IDT Entry code */
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/*
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* Copyright (c) 2012-2014, Wind River Systems, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1) Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2) Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* 3) Neither the name of Wind River Systems nor the names of its contributors
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* may be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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DESCRIPTION
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This header file provides code for constructing an IA-32 interrupt descriptor.
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*/
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#ifndef _IDTENT_H
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#define _IDTENT_H
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#ifdef __cplusplus
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extern"C"
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{
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#endif
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/*
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* Bitmask used to determine which exceptions result in an error code being
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* pushed onto the stack. The following exception vectors push an error code:
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*
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* Vector Mnemonic Description
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* ------ ------- ----------------------
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* 8 #DF Double Fault
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* 10 #TS Invalid TSS
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* 11 #NP Segment Not Present
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* 12 #SS Stack Segment Fault
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* 13 #GP General Protection Fault
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* 14 #PF Page Fault
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* 17 #AC Alignment Check
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*/
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#define _EXC_ERROR_CODE_FAULTS 0x27d00
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/*
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* Interrupt Descriptor Table (IDT) entry structure
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*
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* (This is taken from Intel documentation, so don't try to interpret it
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* too deeply.)
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*/
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typedef struct idtEntry {
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unsigned short lowOffset;
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unsigned short segmentSelector;
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unsigned short reserved:5;
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unsigned short intGateIndicator:8;
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unsigned short descPrivLevel:2;
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unsigned short present:1;
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unsigned short hiOffset;
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} __packed IDT_ENTRY;
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/*******************************************************************************
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*
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* _IdtEntCreate - Create an IDT entry
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*
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* This routine creates an interrupt-gate descriptor at the location defined by
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* <pIdtEntry>. The entry is created such that <routine> is invoked when an
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* interrupt vector is asserted. The <dpl> argument specifies the privilege
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* level for the interrupt-gate descriptor; (hardware) interrupts and exceptions
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* should specify a level of 0, whereas handlers for user-mode software generated
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* interrupts should specify 3.
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*
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* RETURNS: N/A
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*
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* INTERNAL
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* This is a shared routine between the IA-32 nanokernel runtime code and the
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* genIdt host tool code. It is done this way to keep the two sides in sync.
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*
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* The runtime passes a pointer directly to the IDT entry to update whereas the
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* host side simply passes a pointer to a local variable.
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*
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*/
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static inline void _IdtEntCreate
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(
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unsigned long long *pIdtEntry, /* Pointer to where the entry is be built */
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void (*routine)(void *), /* Routine to call when interrupt occurs */
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unsigned int dpl /* priv level for interrupt descriptor */
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)
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{
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unsigned long *pIdtEntry32 = (unsigned long *)pIdtEntry;
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pIdtEntry32[0] = (KERNEL_CODE_SEG_SELECTOR << 16) |
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((unsigned short)(unsigned int)routine);
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/*
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* The constant 0x8e00 results from the following:
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*
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* Segment Present = 1
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*
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* Descriptor Privilege Level (DPL) = 0 (dpl arg will be or'ed in)
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*
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* Interrupt Gate Indicator = 0xE
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* The _IntEnt() and _ExcEnt() stubs assume that an interrupt-gate
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* descriptor is used, and thus they do not issue a 'cli' instruction
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* given that the processor automatically clears the IF flag when
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* accessing the interrupt/exception handler via an interrupt-gate.
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*
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* Size of Gate (D) = 1
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*
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* Reserved = 0
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*/
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pIdtEntry32[1] = ((unsigned int) routine & 0xffff0000) |
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(0x8e00 | (dpl << 13));
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}
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#ifdef __cplusplus
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}
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#endif
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#endif /* _IDTENT_H */
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