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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 memsetb
.global memsetw
.global memcpy
.global memcpy_from_uspace
.global memcpy_from_uspace_failover_address
.global memcpy_to_uspace
.global memcpy_to_uspace_failover_address
# Wrapper for generic memsetb
memsetb:
jmp _memsetb
# Wrapper for generic memsetw
memsetw:
jmp _memsetw
#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_DST(%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 whole words */
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_DST(%esp), %eax /* MEMCPY_DST(%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
# clear Cache Disable and not Write Though
andl $~((1 << 30) | (1 << 29)), %edx
movl %edx,%cr0
jmp 0f
0:
ret
## Enable local APIC
#
# Enable local APIC in MSR.
#
enable_l_apic_in_msr:
movl $0x1b, %ecx
rdmsr
orl $(1 << 11), %eax
orl $(0xfee00000), %eax
wrmsr
ret
# Clear nested flag
# overwrites %ecx
.macro CLEAR_NT_FLAG
pushfl
pop %ecx
and $0xffffbfff, %ecx
push %ecx
popfl
.endm
/*
* The SYSENTER syscall mechanism can be used for syscalls with
* four or fewer arguments. To pass these four arguments, we
* use four registers: EDX, ECX, EBX, ESI. The syscall number
* is passed in EAX. We use EDI to remember the return address
* and EBP to remember the stack. The INT-based syscall mechanism
* can actually handle six arguments plus the syscall number
* entirely in registers.
*/
.global sysenter_handler
sysenter_handler:
pushl %ebp # remember user stack
pushl %edi # remember return user address
pushl %gs # remember TLS
pushl %eax # syscall number
subl $8, %esp # unused sixth and fifth argument
pushl %esi # fourth argument
pushl %ebx # third argument
pushl %ecx # second argument
pushl %edx # first argument
movw $16, %ax
movw %ax, %ds
movw %ax, %es
cld
call syscall_handler
addl $28, %esp # remove arguments from stack
pop %gs # restore TLS
pop %edx # prepare return EIP for SYSEXIT
pop %ecx # prepare userspace ESP for SYSEXIT
sysexit # return to userspace
## 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
pushl %ds
pushl %es
pushl %fs
pushl %gs
#
# Push syscall arguments onto the stack
#
# NOTE: The idea behind the order of arguments passed in registers is to
# use all scratch registers first and preserved registers next.
# An optimized libc syscall wrapper can make use of this setup.
#
pushl %eax
pushl %ebp
pushl %edi
pushl %esi
pushl %ebx
pushl %ecx
pushl %edx
# we must fill the data segment registers
movw $16, %ax
movw %ax, %ds
movw %ax, %es
cld
sti
# syscall_handler(edx, ecx, ebx, esi, edi, ebp, eax)
call syscall_handler
cli
addl $28, %esp # clean-up of parameters
popl %gs
popl %fs
popl %es
popl %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
pushl %ds
pushl %es
pushl %fs
pushl %gs
#ifdef CONFIG_DEBUG_ALLREGS
pushl %ebx
pushl %ebp
pushl %edi
pushl %esi
#else
subl $16, %esp
#endif
pushl %edx
pushl %ecx
pushl %eax
# we must fill the data segment registers
movw $16, %ax
movw %ax, %ds
movw %ax, %es
cld
pushl %esp # *istate
pushl $(\i) # intnum
call exc_dispatch # excdispatch(intnum, *istate)
addl $8, %esp # Clear arguments from stack
CLEAR_NT_FLAG # Modifies %ecx
popl %eax
popl %ecx
popl %edx
#ifdef CONFIG_DEBUG_ALLREGS
popl %esi
popl %edi
popl %ebp
popl %ebx
#else
addl $16, %esp
#endif
popl %gs
popl %fs
popl %es
popl %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