1 /* $NetBSD: patch.c,v 1.9 2007/11/28 18:19:21 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 2007 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Andrew Doran. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 /* 40 * Patch kernel code at boot time, depending on available CPU features. 41 */ 42 43 #include <sys/cdefs.h> 44 __KERNEL_RCSID(0, "$NetBSD: patch.c,v 1.9 2007/11/28 18:19:21 ad Exp $"); 45 46 #include "opt_lockdebug.h" 47 48 #include <sys/types.h> 49 #include <sys/systm.h> 50 51 #include <machine/cpu.h> 52 #include <machine/cpufunc.h> 53 #include <machine/specialreg.h> 54 55 #include <x86/cpuvar.h> 56 #include <x86/cputypes.h> 57 58 void spllower(int); 59 void spllower_end(void); 60 void cx8_spllower(int); 61 void cx8_spllower_end(void); 62 void cx8_spllower_patch(void); 63 64 void mutex_spin_exit_end(void); 65 void i686_mutex_spin_exit(int); 66 void i686_mutex_spin_exit_end(void); 67 void i686_mutex_spin_exit_patch(void); 68 69 void membar_consumer(void); 70 void membar_consumer_end(void); 71 void membar_sync(void); 72 void membar_sync_end(void); 73 void sse2_lfence(void); 74 void sse2_lfence_end(void); 75 void sse2_mfence(void); 76 void sse2_mfence_end(void); 77 78 void mb_read(void); 79 void mb_read_end(void); 80 void mb_memory(void); 81 void mb_memory_end(void); 82 void sse2_mb_read(void); 83 void sse2_mb_read_end(void); 84 void sse2_mb_memory(void); 85 void sse2_mb_memory_end(void); 86 87 extern void *x86_lockpatch[]; 88 extern void *atomic_lockpatch[]; 89 90 #define X86_NOP 0x90 91 #define X86_REP 0xf3 92 #define X86_RET 0xc3 93 #define X86_CS 0x2e 94 #define X86_DS 0x3e 95 #define X86_GROUP_0F 0x0f 96 97 static void __attribute__ ((__unused__)) 98 patchfunc(void *from_s, void *from_e, void *to_s, void *to_e, 99 void *pcrel) 100 { 101 uint8_t *ptr; 102 103 if ((uintptr_t)from_e - (uintptr_t)from_s != 104 (uintptr_t)to_e - (uintptr_t)to_s) 105 panic("patchfunc: sizes do not match (from=%p)", from_s); 106 107 memcpy(to_s, from_s, (uintptr_t)to_e - (uintptr_t)to_s); 108 if (pcrel != NULL) { 109 ptr = pcrel; 110 /* Branch hints */ 111 if (ptr[0] == X86_CS || ptr[0] == X86_DS) 112 ptr++; 113 /* Conditional jumps */ 114 if (ptr[0] == X86_GROUP_0F) 115 ptr++; 116 /* 4-byte relative jump or call */ 117 *(uint32_t *)(ptr + 1 - (uintptr_t)from_s + (uintptr_t)to_s) += 118 ((uint32_t)(uintptr_t)from_s - (uint32_t)(uintptr_t)to_s); 119 } 120 } 121 122 static inline void __attribute__ ((__unused__)) 123 patchbytes(void *addr, const int byte1, const int byte2) 124 { 125 126 ((uint8_t *)addr)[0] = (uint8_t)byte1; 127 if (byte2 != -1) 128 ((uint8_t *)addr)[1] = (uint8_t)byte2; 129 } 130 131 void 132 x86_patch(void) 133 { 134 #if !defined(GPROF) && !defined(LOCKDEBUG) 135 static int again; 136 u_long psl; 137 u_long cr0; 138 139 if (again) 140 return; 141 again = 1; 142 143 /* Disable interrupts. */ 144 psl = x86_read_psl(); 145 x86_disable_intr(); 146 147 /* Disable write protection in supervisor mode. */ 148 cr0 = rcr0(); 149 lcr0(cr0 & ~CR0_WP); 150 151 if (ncpu == 1) { 152 int i; 153 154 /* Uniprocessor: kill LOCK prefixes. */ 155 for (i = 0; x86_lockpatch[i] != 0; i++) 156 patchbytes(x86_lockpatch[i], X86_NOP, -1); 157 for (i = 0; atomic_lockpatch[i] != 0; i++) 158 patchbytes(atomic_lockpatch[i], X86_NOP, -1); 159 /* 160 * Uniprocessor: kill kernel_lock. Fill another 161 * 14 bytes of NOPs so not to confuse the decoder. 162 */ 163 patchbytes(_kernel_lock, X86_NOP, X86_RET); 164 patchbytes(_kernel_unlock, X86_NOP, X86_RET); 165 for (i = 2; i < 16; i++) { 166 patchbytes((char *)_kernel_lock + i, X86_NOP, -1); 167 patchbytes((char *)_kernel_unlock + i, X86_NOP, -1); 168 } 169 } else if ((cpu_feature & CPUID_SSE2) != 0) { 170 /* Faster memory barriers. */ 171 patchfunc( 172 sse2_mb_read, sse2_mb_read_end, 173 mb_read, mb_read_end, 174 NULL 175 ); 176 patchfunc( 177 sse2_mb_memory, sse2_mb_memory_end, 178 mb_memory, mb_memory_end, 179 NULL 180 ); 181 patchfunc( 182 sse2_lfence, sse2_lfence_end, 183 membar_consumer, membar_consumer_end, 184 NULL 185 ); 186 patchfunc( 187 sse2_mfence, sse2_mfence_end, 188 membar_sync, membar_sync_end, 189 NULL 190 ); 191 } 192 193 if ((cpu_feature & CPUID_CX8) != 0) { 194 /* Faster splx(), mutex_spin_exit(). */ 195 patchfunc( 196 cx8_spllower, cx8_spllower_end, 197 spllower, spllower_end, 198 cx8_spllower_patch 199 ); 200 #if defined(i386) 201 patchfunc( 202 i686_mutex_spin_exit, i686_mutex_spin_exit_end, 203 mutex_spin_exit, mutex_spin_exit_end, 204 i686_mutex_spin_exit_patch 205 ); 206 #endif 207 } 208 209 /* Write back and invalidate cache, flush pipelines. */ 210 wbinvd(); 211 x86_flush(); 212 x86_write_psl(psl); 213 214 /* Re-enable write protection. */ 215 lcr0(cr0); 216 #endif /* GPROF */ 217 } 218