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#
# Copyright (C) 2001-2004 Jakub Jermar
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# - Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
# - Redistributions in binary form must reproduce the above copyright
#   notice, this list of conditions and the following disclaimer in the
#   documentation and/or other materials provided with the distribution.
# - The name of the author may not be used to endorse or promote products
#   derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

## very low and hardware-level functions

# Mask for interrupts 0 - 31 (bits 0 - 31) where 0 means that int has no error word
# and 1 means interrupt with error word
#define ERROR_WORD_INTERRUPT_LIST 0x00027D00

.text

.global paging_on
.global enable_l_apic_in_msr
.global interrupt_handlers

## Turn paging on
#
# Enable paging and write-back caching in CR0.
#
paging_on:
    movl %cr0,%edx
    orl $(1<<31),%edx       # paging on
    andl $~((1<<30)|(1<<29)),%edx   # clear Cache Disable and not Write Though
    movl %edx,%cr0
    jmp 0f
0:
    ret


## Enable local APIC
#
# Enable local APIC in MSR.
#
enable_l_apic_in_msr:
    push %eax

    movl $0x1b, %ecx
    rdmsr
    orl $(1<<11),%eax
    orl $(0xfee00000),%eax
    wrmsr

    pop %eax
    ret

# Clear nested flag
# overwrites %ecx
.macro CLEAR_NT_FLAG
    pushfl
    pop %ecx
    and $0xffffbfff,%ecx
    push %ecx
    popfl
.endm   

## Declare interrupt handlers
#
# Declare interrupt handlers for n interrupt
# vectors starting at vector i.
#
# The handlers setup data segment registers
# and call exc_dispatch().
#
#define INTERRUPT_ALIGN 64
.macro handler i n

.ifeq \i-0x30     # Syscall handler
    push %ds
    push %es
    push %fs
    push %gs

    # Push arguments on stack
    push %edi
    push %esi
    push %edx
    push %ecx
    push %eax
    
    # we must fill the data segment registers
    movw $16,%ax
    movw %ax,%ds
    movw %ax,%es
    
    sti
    call syscall_handler   # syscall_handler(ax,cx,dx,si,di)
    cli
    addl $20, %esp         # clean-up of parameters
    
    pop %gs
    pop %fs
    pop %es
    pop %ds
    
    CLEAR_NT_FLAG
    iret
.else   
    /*
     * This macro distinguishes between two versions of ia32 exceptions.
     * One version has error word and the other does not have it.
     * The latter version fakes the error word on the stack so that the
     * handlers and istate_t can be the same for both types.
     */
    .iflt \i-32
        .if (1 << \i) & ERROR_WORD_INTERRUPT_LIST
            /* 
             * With error word, do nothing
             */
                .else
                        /*
                         * Version without error word,
                         */
            subl $4, %esp
                .endif
        .else
                /*
                 * Version without error word,
                 */
        subl $4, %esp
    .endif
    
    push %ds
    push %es
    push %fs
    push %gs

#ifdef CONFIG_DEBUG_ALLREGS
    push %ebx
    push %ebp
    push %edi
    push %esi
#else
    sub $16, %esp
#endif
    push %edx
    push %ecx
    push %eax
    
    # we must fill the data segment registers
    movw $16,%ax
    movw %ax,%ds
    movw %ax,%es

    pushl %esp          # *istate
    pushl $(\i)         # intnum
    call exc_dispatch   # excdispatch(intnum, *istate)
    addl $8,%esp        # Clear arguments from stack

    CLEAR_NT_FLAG # Modifies %ecx
    
    pop %eax
    pop %ecx
    pop %edx
#ifdef CONFIG_DEBUG_ALLREGS
    pop %esi
    pop %edi
    pop %ebp
    pop %ebx
#else
    add $16, %esp
#endif  
    
    pop %gs
    pop %fs
    pop %es
    pop %ds

    addl $4,%esp    # Skip error word, no matter whether real or fake.
    iret
.endif

    .align INTERRUPT_ALIGN
    .if (\n-\i)-1
    handler "(\i+1)",\n
    .endif
.endm

# keep in sync with pm.h !!!
IDT_ITEMS=64
.align INTERRUPT_ALIGN
interrupt_handlers:
h_start:
    handler 0 IDT_ITEMS
h_end:

.data
.global interrupt_handler_size

interrupt_handler_size: .long (h_end-h_start)/IDT_ITEMS