git.joshuawise.com / netwatch.git / blame
| Commit | Line | Data |
|---|---|---|
| 4e3ef36b JW |
1 | /* tables.h |
| 2 | * Linker table helper macros. | |
| 3 | * NetWatch system management mode administration console | |
| 4 | * | |
| 5 | * Copyright 2009, Google Inc. | |
| 6 | * All rights reserved. | |
| 7 | * | |
| 8 | * Redistribution and use in source and binary forms, with or without | |
| 9 | * modification, are permitted provided that the following conditions are | |
| 10 | * met: | |
| 11 | * | |
| 12 | * * Redistributions of source code must retain the above copyright | |
| 13 | * notice, this list of conditions and the following disclaimer. | |
| 14 | * * Redistributions in binary form must reproduce the above | |
| 15 | * copyright notice, this list of conditions and the following disclaimer | |
| 16 | * in the documentation and/or other materials provided with the | |
| 17 | * distribution. | |
| 18 | * * Neither the name of Google Inc. nor the names of its | |
| 19 | * contributors may be used to endorse or promote products derived from | |
| 20 | * this software without specific prior written permission. | |
| 21 | * | |
| 22 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 23 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 24 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
| 25 | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
| 26 | * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
| 27 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
| 28 | * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
| 29 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
| 30 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| 31 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
| 32 | * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 33 | */ | |
| 34 | ||
| 35 | #ifndef __TABLES_H | |
| 36 | #define __TABLES_H | |
| 37 | ||
| 38 | /* Linker tables are a beautiful, evil piece of magic. | |
| 39 | * | |
| 40 | * The idea is this; | |
| 41 | * - For each table, define start and end pointers as zero-length arrays. | |
| 42 | * - Define however many data values as constants of the appropriate type | |
| 43 | * - Put each in its own section. For example, 'start' is in section | |
| 44 | * .table.foo; the data elemnts are in section .table.foo.1 (or other values | |
| 45 | * for explicit ordering); and 'end' is in .table.foo.END. | |
| 46 | * - Merge the sections together with the following linker script entry: | |
| 47 | * *(SORT(.table.*)) | |
| 48 | * | |
| 49 | * This has the effect that the start symbol points to the first value in the | |
| 50 | * table, and the end symbol points to the last. The number of values is | |
| 51 | * simply (table_foo_end - table_foo_start). | |
| 52 | * | |
| 53 | * And everything Just Works. Etherboot and the Linux kernel both use this | |
| 54 | * for identifying linked-in modules; they have a somewhat more elaborate | |
| 55 | * macro infastructure, but at the moment there are only two tables in | |
| 56 | * NetWatch (network protocols and built-in drivers), so less is needed. | |
| 57 | */ | |
| 58 | ||
| 59 | #define PROTOCOL(x) void (* const x##_ptr)(void) \ | |
| 60 | __attribute__((section(".table.protocols.1"))) = x | |
| 61 | ||
| 62 | ||
| 63 | ||
| 64 | #define TABLE(typ, name) \ | |
| 65 | typ name##_table[0] __attribute__((section(".table." #name ))); \ | |
| 66 | typ name##_table_end[0] __attribute__((section(".table." #name ".END"))); | |
| 67 | ||
| 68 | #define TABLE_LENGTH(name) (name##_table_end - name##_table) | |
| 69 | ||
| 70 | #endif /* __TABLES_H */ | |
| 71 |