1 /* 2 * Copyright (C) 2001 Ben. Herrenschmidt (benh@kernel.crashing.org) 3 * 4 * Modifications for ppc64: 5 * Copyright (C) 2003 Dave Engebretsen <engebret@us.ibm.com> 6 * 7 * Copyright 2008 Michael Ellerman, IBM Corporation. 8 * 9 * This program is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU General Public License 11 * as published by the Free Software Foundation; either version 12 * 2 of the License, or (at your option) any later version. 13 */ 14 15 #include <linux/types.h> 16 #include <linux/kernel.h> 17 #include <linux/string.h> 18 #include <linux/init.h> 19 #include <asm/cputable.h> 20 #include <asm/code-patching.h> 21 #include <asm/page.h> 22 #include <asm/sections.h> 23 24 25 struct fixup_entry { 26 unsigned long mask; 27 unsigned long value; 28 long start_off; 29 long end_off; 30 long alt_start_off; 31 long alt_end_off; 32 }; 33 34 static unsigned int *calc_addr(struct fixup_entry *fcur, long offset) 35 { 36 /* 37 * We store the offset to the code as a negative offset from 38 * the start of the alt_entry, to support the VDSO. This 39 * routine converts that back into an actual address. 40 */ 41 return (unsigned int *)((unsigned long)fcur + offset); 42 } 43 44 static int patch_alt_instruction(unsigned int *src, unsigned int *dest, 45 unsigned int *alt_start, unsigned int *alt_end) 46 { 47 unsigned int instr; 48 49 instr = *src; 50 51 if (instr_is_relative_branch(*src)) { 52 unsigned int *target = (unsigned int *)branch_target(src); 53 54 /* Branch within the section doesn't need translating */ 55 if (target < alt_start || target >= alt_end) { 56 instr = translate_branch(dest, src); 57 if (!instr) 58 return 1; 59 } 60 } 61 62 patch_instruction(dest, instr); 63 64 return 0; 65 } 66 67 static int patch_feature_section(unsigned long value, struct fixup_entry *fcur) 68 { 69 unsigned int *start, *end, *alt_start, *alt_end, *src, *dest; 70 71 start = calc_addr(fcur, fcur->start_off); 72 end = calc_addr(fcur, fcur->end_off); 73 alt_start = calc_addr(fcur, fcur->alt_start_off); 74 alt_end = calc_addr(fcur, fcur->alt_end_off); 75 76 if ((alt_end - alt_start) > (end - start)) 77 return 1; 78 79 if ((value & fcur->mask) == fcur->value) 80 return 0; 81 82 src = alt_start; 83 dest = start; 84 85 for (; src < alt_end; src++, dest++) { 86 if (patch_alt_instruction(src, dest, alt_start, alt_end)) 87 return 1; 88 } 89 90 for (; dest < end; dest++) 91 patch_instruction(dest, PPC_INST_NOP); 92 93 return 0; 94 } 95 96 void do_feature_fixups(unsigned long value, void *fixup_start, void *fixup_end) 97 { 98 struct fixup_entry *fcur, *fend; 99 100 fcur = fixup_start; 101 fend = fixup_end; 102 103 for (; fcur < fend; fcur++) { 104 if (patch_feature_section(value, fcur)) { 105 WARN_ON(1); 106 printk("Unable to patch feature section at %p - %p" \ 107 " with %p - %p\n", 108 calc_addr(fcur, fcur->start_off), 109 calc_addr(fcur, fcur->end_off), 110 calc_addr(fcur, fcur->alt_start_off), 111 calc_addr(fcur, fcur->alt_end_off)); 112 } 113 } 114 } 115 116 void do_lwsync_fixups(unsigned long value, void *fixup_start, void *fixup_end) 117 { 118 long *start, *end; 119 unsigned int *dest; 120 121 if (!(value & CPU_FTR_LWSYNC)) 122 return ; 123 124 start = fixup_start; 125 end = fixup_end; 126 127 for (; start < end; start++) { 128 dest = (void *)start + *start; 129 patch_instruction(dest, PPC_INST_LWSYNC); 130 } 131 } 132 133 void do_final_fixups(void) 134 { 135 #if defined(CONFIG_PPC64) && defined(CONFIG_RELOCATABLE) 136 int *src, *dest; 137 unsigned long length; 138 139 if (PHYSICAL_START == 0) 140 return; 141 142 src = (int *)(KERNELBASE + PHYSICAL_START); 143 dest = (int *)KERNELBASE; 144 length = (__end_interrupts - _stext) / sizeof(int); 145 146 while (length--) { 147 patch_instruction(dest, *src); 148 src++; 149 dest++; 150 } 151 #endif 152 } 153 154 #ifdef CONFIG_FTR_FIXUP_SELFTEST 155 156 #define check(x) \ 157 if (!(x)) printk("feature-fixups: test failed at line %d\n", __LINE__); 158 159 /* This must be after the text it fixes up, vmlinux.lds.S enforces that atm */ 160 static struct fixup_entry fixup; 161 162 static long calc_offset(struct fixup_entry *entry, unsigned int *p) 163 { 164 return (unsigned long)p - (unsigned long)entry; 165 } 166 167 static void test_basic_patching(void) 168 { 169 extern unsigned int ftr_fixup_test1; 170 extern unsigned int end_ftr_fixup_test1; 171 extern unsigned int ftr_fixup_test1_orig; 172 extern unsigned int ftr_fixup_test1_expected; 173 int size = &end_ftr_fixup_test1 - &ftr_fixup_test1; 174 175 fixup.value = fixup.mask = 8; 176 fixup.start_off = calc_offset(&fixup, &ftr_fixup_test1 + 1); 177 fixup.end_off = calc_offset(&fixup, &ftr_fixup_test1 + 2); 178 fixup.alt_start_off = fixup.alt_end_off = 0; 179 180 /* Sanity check */ 181 check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_orig, size) == 0); 182 183 /* Check we don't patch if the value matches */ 184 patch_feature_section(8, &fixup); 185 check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_orig, size) == 0); 186 187 /* Check we do patch if the value doesn't match */ 188 patch_feature_section(0, &fixup); 189 check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_expected, size) == 0); 190 191 /* Check we do patch if the mask doesn't match */ 192 memcpy(&ftr_fixup_test1, &ftr_fixup_test1_orig, size); 193 check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_orig, size) == 0); 194 patch_feature_section(~8, &fixup); 195 check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_expected, size) == 0); 196 } 197 198 static void test_alternative_patching(void) 199 { 200 extern unsigned int ftr_fixup_test2; 201 extern unsigned int end_ftr_fixup_test2; 202 extern unsigned int ftr_fixup_test2_orig; 203 extern unsigned int ftr_fixup_test2_alt; 204 extern unsigned int ftr_fixup_test2_expected; 205 int size = &end_ftr_fixup_test2 - &ftr_fixup_test2; 206 207 fixup.value = fixup.mask = 0xF; 208 fixup.start_off = calc_offset(&fixup, &ftr_fixup_test2 + 1); 209 fixup.end_off = calc_offset(&fixup, &ftr_fixup_test2 + 2); 210 fixup.alt_start_off = calc_offset(&fixup, &ftr_fixup_test2_alt); 211 fixup.alt_end_off = calc_offset(&fixup, &ftr_fixup_test2_alt + 1); 212 213 /* Sanity check */ 214 check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_orig, size) == 0); 215 216 /* Check we don't patch if the value matches */ 217 patch_feature_section(0xF, &fixup); 218 check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_orig, size) == 0); 219 220 /* Check we do patch if the value doesn't match */ 221 patch_feature_section(0, &fixup); 222 check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_expected, size) == 0); 223 224 /* Check we do patch if the mask doesn't match */ 225 memcpy(&ftr_fixup_test2, &ftr_fixup_test2_orig, size); 226 check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_orig, size) == 0); 227 patch_feature_section(~0xF, &fixup); 228 check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_expected, size) == 0); 229 } 230 231 static void test_alternative_case_too_big(void) 232 { 233 extern unsigned int ftr_fixup_test3; 234 extern unsigned int end_ftr_fixup_test3; 235 extern unsigned int ftr_fixup_test3_orig; 236 extern unsigned int ftr_fixup_test3_alt; 237 int size = &end_ftr_fixup_test3 - &ftr_fixup_test3; 238 239 fixup.value = fixup.mask = 0xC; 240 fixup.start_off = calc_offset(&fixup, &ftr_fixup_test3 + 1); 241 fixup.end_off = calc_offset(&fixup, &ftr_fixup_test3 + 2); 242 fixup.alt_start_off = calc_offset(&fixup, &ftr_fixup_test3_alt); 243 fixup.alt_end_off = calc_offset(&fixup, &ftr_fixup_test3_alt + 2); 244 245 /* Sanity check */ 246 check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0); 247 248 /* Expect nothing to be patched, and the error returned to us */ 249 check(patch_feature_section(0xF, &fixup) == 1); 250 check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0); 251 check(patch_feature_section(0, &fixup) == 1); 252 check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0); 253 check(patch_feature_section(~0xF, &fixup) == 1); 254 check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0); 255 } 256 257 static void test_alternative_case_too_small(void) 258 { 259 extern unsigned int ftr_fixup_test4; 260 extern unsigned int end_ftr_fixup_test4; 261 extern unsigned int ftr_fixup_test4_orig; 262 extern unsigned int ftr_fixup_test4_alt; 263 extern unsigned int ftr_fixup_test4_expected; 264 int size = &end_ftr_fixup_test4 - &ftr_fixup_test4; 265 unsigned long flag; 266 267 /* Check a high-bit flag */ 268 flag = 1UL << ((sizeof(unsigned long) - 1) * 8); 269 fixup.value = fixup.mask = flag; 270 fixup.start_off = calc_offset(&fixup, &ftr_fixup_test4 + 1); 271 fixup.end_off = calc_offset(&fixup, &ftr_fixup_test4 + 5); 272 fixup.alt_start_off = calc_offset(&fixup, &ftr_fixup_test4_alt); 273 fixup.alt_end_off = calc_offset(&fixup, &ftr_fixup_test4_alt + 2); 274 275 /* Sanity check */ 276 check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_orig, size) == 0); 277 278 /* Check we don't patch if the value matches */ 279 patch_feature_section(flag, &fixup); 280 check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_orig, size) == 0); 281 282 /* Check we do patch if the value doesn't match */ 283 patch_feature_section(0, &fixup); 284 check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_expected, size) == 0); 285 286 /* Check we do patch if the mask doesn't match */ 287 memcpy(&ftr_fixup_test4, &ftr_fixup_test4_orig, size); 288 check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_orig, size) == 0); 289 patch_feature_section(~flag, &fixup); 290 check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_expected, size) == 0); 291 } 292 293 static void test_alternative_case_with_branch(void) 294 { 295 extern unsigned int ftr_fixup_test5; 296 extern unsigned int end_ftr_fixup_test5; 297 extern unsigned int ftr_fixup_test5_expected; 298 int size = &end_ftr_fixup_test5 - &ftr_fixup_test5; 299 300 check(memcmp(&ftr_fixup_test5, &ftr_fixup_test5_expected, size) == 0); 301 } 302 303 static void test_alternative_case_with_external_branch(void) 304 { 305 extern unsigned int ftr_fixup_test6; 306 extern unsigned int end_ftr_fixup_test6; 307 extern unsigned int ftr_fixup_test6_expected; 308 int size = &end_ftr_fixup_test6 - &ftr_fixup_test6; 309 310 check(memcmp(&ftr_fixup_test6, &ftr_fixup_test6_expected, size) == 0); 311 } 312 313 static void test_cpu_macros(void) 314 { 315 extern u8 ftr_fixup_test_FTR_macros; 316 extern u8 ftr_fixup_test_FTR_macros_expected; 317 unsigned long size = &ftr_fixup_test_FTR_macros_expected - 318 &ftr_fixup_test_FTR_macros; 319 320 /* The fixups have already been done for us during boot */ 321 check(memcmp(&ftr_fixup_test_FTR_macros, 322 &ftr_fixup_test_FTR_macros_expected, size) == 0); 323 } 324 325 static void test_fw_macros(void) 326 { 327 #ifdef CONFIG_PPC64 328 extern u8 ftr_fixup_test_FW_FTR_macros; 329 extern u8 ftr_fixup_test_FW_FTR_macros_expected; 330 unsigned long size = &ftr_fixup_test_FW_FTR_macros_expected - 331 &ftr_fixup_test_FW_FTR_macros; 332 333 /* The fixups have already been done for us during boot */ 334 check(memcmp(&ftr_fixup_test_FW_FTR_macros, 335 &ftr_fixup_test_FW_FTR_macros_expected, size) == 0); 336 #endif 337 } 338 339 static void test_lwsync_macros(void) 340 { 341 extern u8 lwsync_fixup_test; 342 extern u8 end_lwsync_fixup_test; 343 extern u8 lwsync_fixup_test_expected_LWSYNC; 344 extern u8 lwsync_fixup_test_expected_SYNC; 345 unsigned long size = &end_lwsync_fixup_test - 346 &lwsync_fixup_test; 347 348 /* The fixups have already been done for us during boot */ 349 if (cur_cpu_spec->cpu_features & CPU_FTR_LWSYNC) { 350 check(memcmp(&lwsync_fixup_test, 351 &lwsync_fixup_test_expected_LWSYNC, size) == 0); 352 } else { 353 check(memcmp(&lwsync_fixup_test, 354 &lwsync_fixup_test_expected_SYNC, size) == 0); 355 } 356 } 357 358 static int __init test_feature_fixups(void) 359 { 360 printk(KERN_DEBUG "Running feature fixup self-tests ...\n"); 361 362 test_basic_patching(); 363 test_alternative_patching(); 364 test_alternative_case_too_big(); 365 test_alternative_case_too_small(); 366 test_alternative_case_with_branch(); 367 test_alternative_case_with_external_branch(); 368 test_cpu_macros(); 369 test_fw_macros(); 370 test_lwsync_macros(); 371 372 return 0; 373 } 374 late_initcall(test_feature_fixups); 375 376 #endif /* CONFIG_FTR_FIXUP_SELFTEST */ 377