0,0 → 1,84 |
# |
# 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. |
# |
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.text |
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.global context_save |
.global context_restore |
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## Save current CPU context |
# |
# Save CPU context to the context_t variable |
# pointed by the 1st argument. Returns 1 in EAX. |
# |
context_save: |
movl 0(%esp),%eax # the caller's return %eip |
movl 4(%esp),%edx # address of the context variable to save context to |
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movl %esp,0(%edx) # %esp -> ctx->sp |
movl %eax,4(%edx) # %eip -> ctx->pc |
movl %ebx,8(%edx) # %ebx -> ctx->ebx |
movl %esi,12(%edx) # %esi -> ctx->esi |
movl %edi,16(%edx) # %edi -> ctx->edi |
movl %ebp,20(%edx) # %ebp -> ctx->ebp |
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# Save TLS |
movl %gs:0, %eax |
movl %eax, 24(%edx) # tls -> ctx->tls |
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xorl %eax,%eax # context_save returns 1 |
incl %eax |
ret |
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## Restore saved CPU context |
# |
# Restore CPU context from context_t variable |
# pointed by the 1st argument. Returns 0 in EAX. |
# |
context_restore: |
movl 4(%esp),%eax # address of the context variable to restore context from |
movl 0(%eax),%esp # ctx->sp -> %esp |
movl 4(%eax),%edx # ctx->pc -> %edx |
movl 8(%eax),%ebx # ctx->ebx -> %ebx |
movl 12(%eax),%esi # ctx->esi -> %esi |
movl 16(%eax),%edi # ctx->edi -> %edi |
movl 20(%eax),%ebp # ctx->ebp -> %ebp |
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movl %edx,0(%esp) # ctx->pc -> saver's return %eip |
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# Set thread local storage |
pushl %edx |
movl 24(%eax), %edx # Set arg1 to TLS addr |
movl $1, %eax # Syscall SYS_TLS_SET |
int $0x30 |
popl %edx |
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xorl %eax,%eax # context_restore returns 0 |
ret |