117 lines
3.0 KiB
ArmAsm
117 lines
3.0 KiB
ArmAsm
/* Copyright (C) 2005 David Decotigny
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Copyright (C) 2004 The KOS Team
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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USA.
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*/
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#include "segment.h"
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/**
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* @file swintr_wrappers.S
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*
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* The SOS low-level handlers for the software interrupts. Currently
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* only 1 wrapper: that for the SOS syscalls.
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*/
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.file "swintr_wrappers.S"
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.text
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/* The address of the real "C" syscall function */
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.extern sos_do_syscall
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/** Update the kernel TSS in case we are switching to a thread in user
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mode in order to come back into the correct kernel stack */
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.extern sos_cpu_context_update_kernel_tss
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/* The address of the function to call to set back the user thread's
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MMU configuration upon return to user context */
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.extern sos_thread_prepare_syscall_switch_back
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.p2align 2, 0x90
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.globl sos_syscall_wrapper
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sos_syscall_wrapper:
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.type sos_syscall_wrapper,@function
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/* Fake error code */
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pushl $0
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/* Backup the context */
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pushl %ebp
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movl %esp, %ebp
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pushl %edi
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pushl %esi
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pushl %edx
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pushl %ecx
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pushl %ebx
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pushl %eax
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subl $2,%esp
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pushw %ss
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pushw %ds
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pushw %es
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pushw %fs
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pushw %gs
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/* Set correct kernel segment descriptors' value */
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movw $SOS_BUILD_SEGMENT_REG_VALUE(0, 0, SOS_SEG_KDATA), %di
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pushw %di ; popw %ds
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pushw %di ; popw %es
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pushw %di ; popw %fs
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pushw %di ; popw %gs
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/* Prepare the call to do_syscall */
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pushl %esp /* user_ctxt */
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pushl %eax /* syscall ID */
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call sos_do_syscall
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/* Unallocate the stack used by the
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do_syscall arguments */
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addl $8, %esp
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/* store the do_syscall return value into interrupted context */
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movl %eax, 12(%esp)
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/* Set the MMU configuration to that of the user thread's process */
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pushl %esp /* user_ctxt */
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call sos_thread_prepare_syscall_switch_back
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addl $4, %esp /* Unallocate the stack */
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/* Prepare kernel TSS because we are switching back to a user
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thread: we make sure that we will come back into the kernel at a
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correct stack location */
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pushl %esp /* Pass the location of the context we are
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restoring to the function */
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call sos_cpu_context_update_kernel_tss
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addl $4, %esp
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/* Restore the user context */
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popw %gs
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popw %fs
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popw %es
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popw %ds
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popw %ss
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addl $2,%esp
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popl %eax /* This is the return value of do_syscall (see above) */
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popl %ebx
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popl %ecx
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popl %edx
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popl %esi
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popl %edi
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popl %ebp
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/* Remove fake error code */
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addl $4, %esp
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iret
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