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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

.global memcpy

.global memcpy_from_uspace

.global memcpy_from_uspace_failover_address

.global memcpy_to_uspace

.global memcpy_to_uspace_failover_address

#define MEMCPY_DST	4

#define MEMCPY_SRC	8

#define MEMCPY_SIZE	12

/** Copy memory to/from userspace.

 *

 * This is almost conventional memcpy().

 * The difference is that there is a failover part

 * to where control is returned from a page fault

 * if the page fault occurs during copy_from_uspace()

 * or copy_to_uspace().

 *

 * @param MEMCPY_DST(%esp)	Destination address.

 * @param MEMCPY_SRC(%esp)	Source address.

 * @param MEMCPY_SIZE(%esp)	Size.

 *

 * @return MEMCPY_SRC(%esp) on success and 0 on failure.

 */

memcpy:

memcpy_from_uspace:

memcpy_to_uspace:

	movl %edi, %edx				/* save %edi */

	movl %esi, %eax				/* save %esi */

	movl MEMCPY_SIZE(%esp), %ecx

	shrl $2, %ecx				/* size / 4 */

	movl MEMCPY_DST(%esp), %edi

	movl MEMCPY_SRC(%esp), %esi

	rep movsl				/* copy as much as possible word by word */

	movl MEMCPY_SIZE(%esp), %ecx

	andl $3, %ecx				/* size % 4 */

	jz 0f

	rep movsb				/* copy the rest byte by byte */

0:

	movl %edx, %edi

	movl %eax, %esi

	movl MEMCPY_SRC(%esp), %eax		/* MEMCPY_SRC(%esp), success */

	ret

/*

 * We got here from as_page_fault() after the memory operations

 * above had caused a page fault.

 */

memcpy_from_uspace_failover_address:

memcpy_to_uspace_failover_address:

	movl %edx, %edi

	movl %eax, %esi

	xorl %eax, %eax				/* return 0, failure */

	ret

## 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