projects / apple / xnu.git / blame
| Commit | Line | Data |
|---|---|---|
| 55e303ae A |
1 | /* |
| 2 | * Copyright (c) 2003 Apple Computer, Inc. All rights reserved. | |
| 3 | * | |
| 4 | * @APPLE_LICENSE_HEADER_START@ | |
| 5 | * | |
| 37839358 A |
6 | * The contents of this file constitute Original Code as defined in and |
| 7 | * are subject to the Apple Public Source License Version 1.1 (the | |
| 8 | * "License"). You may not use this file except in compliance with the | |
| 9 | * License. Please obtain a copy of the License at | |
| 10 | * http://www.apple.com/publicsource and read it before using this file. | |
| 55e303ae | 11 | * |
| 37839358 A |
12 | * This Original Code and all software distributed under the License are |
| 13 | * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER | |
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14 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
| 15 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, | |
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16 | * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the |
| 17 | * License for the specific language governing rights and limitations | |
| 18 | * under the License. | |
| 55e303ae A |
19 | * |
| 20 | * @APPLE_LICENSE_HEADER_END@ | |
| 21 | */ | |
| 22 | ||
| 23 | #define __NO_UNDERSCORES__ | |
| 24 | #include <i386/asm.h> | |
| 25 | #include <assym.s> | |
| 26 | ||
| 27 | Entry(mcount) | |
| 28 | pushl %ebp // setup mcount's frame | |
| 29 | movl %esp,%ebp | |
| 91447636 | 30 | pushl %eax // save %eax |
| 55e303ae A |
31 | pushf // save interrupt state |
| 32 | cli // disable interrupts | |
| 33 | ||
| 55e303ae A |
34 | // |
| 35 | // Check that this cpu is ready. | |
| 36 | // This delays the start of mcounting until a cpu is really prepared. | |
| 37 | // | |
| 91447636 | 38 | movl %gs:CPU_RUNNING,%eax |
| 55e303ae A |
39 | testl %eax,%eax |
| 40 | jz 1f | |
| 41 | ||
| 42 | // | |
| 43 | // Test for recursion as indicated by a per-cpu flag. | |
| 44 | // Skip if nested, otherwise set the flag and call the C mount(). | |
| 45 | // | |
| 91447636 | 46 | movl %gs:CPU_MCOUNT_OFF,%eax |
| 55e303ae A |
47 | testl %eax,%eax // test for recursion |
| 48 | jnz 1f | |
| 91447636 A |
49 | |
| 50 | incl %gs:CPU_MCOUNT_OFF // set recursion flag | |
| 55e303ae A |
51 | |
| 52 | movl (%ebp),%eax // frame pointer of mcount's caller | |
| 53 | movl 4(%eax),%eax // mcount's caller's return address | |
| 54 | pushl 4(%ebp) // push selfpc parameter for mcount() | |
| 55 | pushl %eax // push frompc parameter for mcount() | |
| 56 | call _mcount // call the C mcount | |
| 57 | addl $8,%esp // pop args | |
| 58 | ||
| 91447636 | 59 | decl %gs:CPU_MCOUNT_OFF // turn off recursion flag |
| 55e303ae A |
60 | 1: |
| 61 | popf // restore interrupt state | |
| 91447636 | 62 | popl %eax |
| 55e303ae A |
63 | movl %ebp,%esp // tear down mcount's frame |
| 64 | popl %ebp | |
| 65 | ret |