1 /* $NetBSD: patch.c,v 1.16 2009/02/17 21:20:49 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 2007, 2008, 2009 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 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Patch kernel code at boot time, depending on available CPU features. 34 */ 35 36 #include <sys/cdefs.h> 37 __KERNEL_RCSID(0, "$NetBSD: patch.c,v 1.16 2009/02/17 21:20:49 ad Exp $"); 38 39 #include "opt_lockdebug.h" 40 41 #include <sys/types.h> 42 #include <sys/systm.h> 43 44 #include <machine/cpu.h> 45 #include <machine/cpufunc.h> 46 #include <machine/specialreg.h> 47 48 #include <x86/cpuvar.h> 49 #include <x86/cputypes.h> 50 51 void spllower(int); 52 void spllower_end(void); 53 void cx8_spllower(int); 54 void cx8_spllower_end(void); 55 void cx8_spllower_patch(void); 56 57 void mutex_spin_exit_end(void); 58 void i686_mutex_spin_exit(int); 59 void i686_mutex_spin_exit_end(void); 60 void i686_mutex_spin_exit_patch(void); 61 62 void membar_consumer(void); 63 void membar_consumer_end(void); 64 void membar_sync(void); 65 void membar_sync_end(void); 66 void sse2_lfence(void); 67 void sse2_lfence_end(void); 68 void sse2_mfence(void); 69 void sse2_mfence_end(void); 70 71 void _atomic_cas_64(void); 72 void _atomic_cas_64_end(void); 73 void _atomic_cas_cx8(void); 74 void _atomic_cas_cx8_end(void); 75 76 extern void *x86_lockpatch[]; 77 extern void *atomic_lockpatch[]; 78 79 #define X86_NOP 0x90 80 #define X86_REP 0xf3 81 #define X86_RET 0xc3 82 #define X86_CS 0x2e 83 #define X86_DS 0x3e 84 #define X86_GROUP_0F 0x0f 85 86 static void __unused 87 patchfunc(void *from_s, void *from_e, void *to_s, void *to_e, 88 void *pcrel) 89 { 90 uint8_t *ptr; 91 92 if ((uintptr_t)from_e - (uintptr_t)from_s != 93 (uintptr_t)to_e - (uintptr_t)to_s) 94 panic("patchfunc: sizes do not match (from=%p)", from_s); 95 96 memcpy(to_s, from_s, (uintptr_t)to_e - (uintptr_t)to_s); 97 if (pcrel != NULL) { 98 ptr = pcrel; 99 /* Branch hints */ 100 if (ptr[0] == X86_CS || ptr[0] == X86_DS) 101 ptr++; 102 /* Conditional jumps */ 103 if (ptr[0] == X86_GROUP_0F) 104 ptr++; 105 /* 4-byte relative jump or call */ 106 *(uint32_t *)(ptr + 1 - (uintptr_t)from_s + (uintptr_t)to_s) += 107 ((uint32_t)(uintptr_t)from_s - (uint32_t)(uintptr_t)to_s); 108 } 109 } 110 111 static inline void __unused 112 patchbytes(void *addr, const int byte1, const int byte2) 113 { 114 115 ((uint8_t *)addr)[0] = (uint8_t)byte1; 116 if (byte2 != -1) 117 ((uint8_t *)addr)[1] = (uint8_t)byte2; 118 } 119 120 void 121 x86_patch(bool early) 122 { 123 static bool first, second; 124 u_long psl; 125 u_long cr0; 126 127 if (early) { 128 if (first) 129 return; 130 first = true; 131 } else { 132 if (second) 133 return; 134 second = true; 135 } 136 137 /* Disable interrupts. */ 138 psl = x86_read_psl(); 139 x86_disable_intr(); 140 141 /* Disable write protection in supervisor mode. */ 142 cr0 = rcr0(); 143 lcr0(cr0 & ~CR0_WP); 144 145 #if !defined(GPROF) 146 if (!early && ncpu == 1) { 147 #ifndef LOCKDEBUG 148 int i; 149 150 /* Uniprocessor: kill LOCK prefixes. */ 151 for (i = 0; x86_lockpatch[i] != 0; i++) 152 patchbytes(x86_lockpatch[i], X86_NOP, -1); 153 for (i = 0; atomic_lockpatch[i] != 0; i++) 154 patchbytes(atomic_lockpatch[i], X86_NOP, -1); 155 #endif /* !LOCKDEBUG */ 156 } 157 if (!early && (cpu_feature & CPUID_SSE2) != 0) { 158 /* Faster memory barriers. */ 159 patchfunc( 160 sse2_lfence, sse2_lfence_end, 161 membar_consumer, membar_consumer_end, 162 NULL 163 ); 164 patchfunc( 165 sse2_mfence, sse2_mfence_end, 166 membar_sync, membar_sync_end, 167 NULL 168 ); 169 } 170 #endif /* GPROF */ 171 172 #ifdef i386 173 /* 174 * Patch early and late. Second time around the 'lock' prefix 175 * may be gone. 176 */ 177 if ((cpu_feature & CPUID_CX8) != 0) { 178 patchfunc( 179 _atomic_cas_cx8, _atomic_cas_cx8_end, 180 _atomic_cas_64, _atomic_cas_64_end, 181 NULL 182 ); 183 } 184 #endif /* i386 */ 185 186 if (!early && (cpu_feature & CPUID_CX8) != 0) { 187 /* Faster splx(), mutex_spin_exit(). */ 188 patchfunc( 189 cx8_spllower, cx8_spllower_end, 190 spllower, spllower_end, 191 cx8_spllower_patch 192 ); 193 #if defined(i386) && !defined(LOCKDEBUG) 194 patchfunc( 195 i686_mutex_spin_exit, i686_mutex_spin_exit_end, 196 mutex_spin_exit, mutex_spin_exit_end, 197 i686_mutex_spin_exit_patch 198 ); 199 #endif /* !LOCKDEBUG */ 200 } 201 202 /* Write back and invalidate cache, flush pipelines. */ 203 wbinvd(); 204 x86_flush(); 205 x86_write_psl(psl); 206 207 /* Re-enable write protection. */ 208 lcr0(cr0); 209 } 210