| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * This file contains miscellaneous low-level functions. |
| 3 | * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) |
| 4 | * |
| 5 | * Largely rewritten by Cort Dougan (cort@cs.nmt.edu) |
| 6 | * and Paul Mackerras. |
| 7 | * |
| 8 | * A couple of functions stolen from arch/ppc/kernel/misc.S for UML |
| 9 | * by Chris Emerson. |
| 10 | * |
| 11 | * This program is free software; you can redistribute it and/or |
| 12 | * modify it under the terms of the GNU General Public License |
| 13 | * as published by the Free Software Foundation; either version |
| 14 | * 2 of the License, or (at your option) any later version. |
| 15 | * |
| 16 | */ |
| 17 | |
| 18 | #include <linux/config.h> |
| 19 | #include <asm/processor.h> |
| 20 | #include "ppc_asm.h" |
| 21 | |
| 22 | #if defined(CONFIG_4xx) || defined(CONFIG_8xx) |
| 23 | #define CACHE_LINE_SIZE 16 |
| 24 | #define LG_CACHE_LINE_SIZE 4 |
| 25 | #define MAX_COPY_PREFETCH 1 |
| 26 | #elif !defined(CONFIG_PPC64BRIDGE) |
| 27 | #define CACHE_LINE_SIZE 32 |
| 28 | #define LG_CACHE_LINE_SIZE 5 |
| 29 | #define MAX_COPY_PREFETCH 4 |
| 30 | #else |
| 31 | #define CACHE_LINE_SIZE 128 |
| 32 | #define LG_CACHE_LINE_SIZE 7 |
| 33 | #define MAX_COPY_PREFETCH 1 |
| 34 | #endif /* CONFIG_4xx || CONFIG_8xx */ |
| 35 | |
| 36 | .text |
| 37 | |
| 38 | /* |
| 39 | * Clear a page using the dcbz instruction, which doesn't cause any |
| 40 | * memory traffic (except to write out any cache lines which get |
| 41 | * displaced). This only works on cacheable memory. |
| 42 | */ |
| 43 | _GLOBAL(clear_page) |
| 44 | li r0,4096/CACHE_LINE_SIZE |
| 45 | mtctr r0 |
| 46 | #ifdef CONFIG_8xx |
| 47 | li r4, 0 |
| 48 | 1: stw r4, 0(r3) |
| 49 | stw r4, 4(r3) |
| 50 | stw r4, 8(r3) |
| 51 | stw r4, 12(r3) |
| 52 | #else |
| 53 | 1: dcbz 0,r3 |
| 54 | #endif |
| 55 | addi r3,r3,CACHE_LINE_SIZE |
| 56 | bdnz 1b |
| 57 | blr |
| 58 | |
| 59 | /* |
| 60 | * Copy a whole page. We use the dcbz instruction on the destination |
| 61 | * to reduce memory traffic (it eliminates the unnecessary reads of |
| 62 | * the destination into cache). This requires that the destination |
| 63 | * is cacheable. |
| 64 | */ |
| 65 | #define COPY_16_BYTES \ |
| 66 | lwz r6,4(r4); \ |
| 67 | lwz r7,8(r4); \ |
| 68 | lwz r8,12(r4); \ |
| 69 | lwzu r9,16(r4); \ |
| 70 | stw r6,4(r3); \ |
| 71 | stw r7,8(r3); \ |
| 72 | stw r8,12(r3); \ |
| 73 | stwu r9,16(r3) |
| 74 | |
| 75 | _GLOBAL(copy_page) |
| 76 | addi r3,r3,-4 |
| 77 | addi r4,r4,-4 |
| 78 | li r5,4 |
| 79 | |
| 80 | #ifndef CONFIG_8xx |
| 81 | #if MAX_COPY_PREFETCH > 1 |
| 82 | li r0,MAX_COPY_PREFETCH |
| 83 | li r11,4 |
| 84 | mtctr r0 |
| 85 | 11: dcbt r11,r4 |
| 86 | addi r11,r11,CACHE_LINE_SIZE |
| 87 | bdnz 11b |
| 88 | #else /* MAX_COPY_PREFETCH == 1 */ |
| 89 | dcbt r5,r4 |
| 90 | li r11,CACHE_LINE_SIZE+4 |
| 91 | #endif /* MAX_COPY_PREFETCH */ |
| 92 | #endif /* CONFIG_8xx */ |
| 93 | |
| 94 | li r0,4096/CACHE_LINE_SIZE |
| 95 | mtctr r0 |
| 96 | 1: |
| 97 | #ifndef CONFIG_8xx |
| 98 | dcbt r11,r4 |
| 99 | dcbz r5,r3 |
| 100 | #endif |
| 101 | COPY_16_BYTES |
| 102 | #if CACHE_LINE_SIZE >= 32 |
| 103 | COPY_16_BYTES |
| 104 | #if CACHE_LINE_SIZE >= 64 |
| 105 | COPY_16_BYTES |
| 106 | COPY_16_BYTES |
| 107 | #if CACHE_LINE_SIZE >= 128 |
| 108 | COPY_16_BYTES |
| 109 | COPY_16_BYTES |
| 110 | COPY_16_BYTES |
| 111 | COPY_16_BYTES |
| 112 | #endif |
| 113 | #endif |
| 114 | #endif |
| 115 | bdnz 1b |
| 116 | blr |