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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 1120 | palkovsky | 1 | # |
| 2 | # Copyright (C) 2001-2004 Jakub Jermar |
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| 3 | # All rights reserved. |
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| 4 | # |
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| 5 | # Redistribution and use in source and binary forms, with or without |
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| 6 | # modification, are permitted provided that the following conditions |
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| 7 | # are met: |
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| 8 | # |
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| 9 | # - Redistributions of source code must retain the above copyright |
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| 10 | # notice, this list of conditions and the following disclaimer. |
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| 11 | # - Redistributions in binary form must reproduce the above copyright |
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| 12 | # notice, this list of conditions and the following disclaimer in the |
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| 13 | # documentation and/or other materials provided with the distribution. |
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| 14 | # - The name of the author may not be used to endorse or promote products |
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| 15 | # derived from this software without specific prior written permission. |
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| 16 | # |
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| 17 | # THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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| 18 | # IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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| 19 | # OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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| 20 | # IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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| 21 | # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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| 22 | # NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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| 23 | # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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| 24 | # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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| 25 | # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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| 26 | # THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 27 | # |
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| 28 | |||
| 29 | .text |
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| 30 | |||
| 31 | .global context_save |
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| 32 | .global context_restore |
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| 33 | |||
| 34 | |||
| 35 | ## Save current CPU context |
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| 36 | # |
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| 37 | # Save CPU context to the context_t variable |
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| 38 | # pointed by the 1st argument. Returns 1 in EAX. |
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| 39 | # |
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| 40 | context_save: |
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| 41 | movl 0(%esp),%eax # the caller's return %eip |
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| 42 | movl 4(%esp),%edx # address of the kernel_context variable to save context to |
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| 43 | |||
| 44 | movl %esp,0(%edx) # %esp -> ctx->sp |
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| 45 | movl %eax,4(%edx) # %eip -> ctx->pc |
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| 46 | movl %ebx,8(%edx) # %ebx -> ctx->ebx |
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| 47 | movl %esi,12(%edx) # %esi -> ctx->esi |
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| 48 | movl %edi,16(%edx) # %edi -> ctx->edi |
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| 49 | movl %ebp,20(%edx) # %ebp -> ctx->ebp |
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| 50 | |||
| 51 | # Save TLS |
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| 52 | movl %gs:0, %eax |
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| 53 | movl %eax, 24(%edx) # tls -> ctx->tls |
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| 54 | |||
| 55 | xorl %eax,%eax # context_save returns 1 |
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| 56 | incl %eax |
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| 57 | ret |
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| 58 | |||
| 59 | |||
| 60 | ## Restore saved CPU context |
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| 61 | # |
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| 62 | # Restore CPU context from context_t variable |
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| 63 | # pointed by the 1st argument. Returns 0 in EAX. |
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| 64 | # |
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| 65 | context_restore: |
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| 66 | movl 4(%esp),%eax # address of the kernel_context variable to restore context from |
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| 67 | movl 0(%eax),%esp # ctx->sp -> %esp |
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| 68 | movl 4(%eax),%edx # ctx->pc -> %edx |
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| 69 | movl 8(%eax),%ebx # ctx->ebx -> %ebx |
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| 70 | movl 12(%eax),%esi # ctx->esi -> %esi |
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| 71 | movl 16(%eax),%edi # ctx->edi -> %edi |
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| 72 | movl 20(%eax),%ebp # ctx->ebp -> %ebp |
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| 73 | |||
| 74 | movl %edx,0(%esp) # ctx->pc -> saver's return %eip |
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| 1391 | palkovsky | 75 | |
| 1120 | palkovsky | 76 | # Set thread local storage |
| 1391 | palkovsky | 77 | pushl %edi |
| 1120 | palkovsky | 78 | movl 24(%eax), %eax # Set arg1 to TLS addr |
| 79 | movl $1, %edi # Syscall 1 |
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| 80 | int $0x30 |
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| 1391 | palkovsky | 81 | popl %edi |
| 1120 | palkovsky | 82 | |
| 83 | xorl %eax,%eax # context_restore returns 0 |
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| 84 | ret |