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 #include <asm/setup.h> 24 #include <asm/firmware.h> 25 26 struct fixup_entry { 27 unsigned long mask; 28 unsigned long value; 29 long start_off; 30 long end_off; 31 long alt_start_off; 32 long alt_end_off; 33 }; 34 35 static unsigned int *calc_addr(struct fixup_entry *fcur, long offset) 36 { 37 /* 38 * We store the offset to the code as a negative offset from 39 * the start of the alt_entry, to support the VDSO. This 40 * routine converts that back into an actual address. 41 */ 42 return (unsigned int *)((unsigned long)fcur + offset); 43 } 44 45 static int patch_alt_instruction(unsigned int *src, unsigned int *dest, 46 unsigned int *alt_start, unsigned int *alt_end) 47 { 48 unsigned int instr; 49 50 instr = *src; 51 52 if (instr_is_relative_branch(*src)) { 53 unsigned int *target = (unsigned int *)branch_target(src); 54 55 /* Branch within the section doesn't need translating */ 56 if (target < alt_start || target >= alt_end) { 57 instr = translate_branch(dest, src); 58 if (!instr) 59 return 1; 60 } 61 } 62 63 patch_instruction(dest, instr); 64 65 return 0; 66 } 67 68 static int patch_feature_section(unsigned long value, struct fixup_entry *fcur) 69 { 70 unsigned int *start, *end, *alt_start, *alt_end, *src, *dest; 71 72 start = calc_addr(fcur, fcur->start_off); 73 end = calc_addr(fcur, fcur->end_off); 74 alt_start = calc_addr(fcur, fcur->alt_start_off); 75 alt_end = calc_addr(fcur, fcur->alt_end_off); 76 77 if ((alt_end - alt_start) > (end - start)) 78 return 1; 79 80 if ((value & fcur->mask) == fcur->value) 81 return 0; 82 83 src = alt_start; 84 dest = start; 85 86 for (; src < alt_end; src++, dest++) { 87 if (patch_alt_instruction(src, dest, alt_start, alt_end)) 88 return 1; 89 } 90 91 for (; dest < end; dest++) 92 patch_instruction(dest, PPC_INST_NOP); 93 94 return 0; 95 } 96 97 void do_feature_fixups(unsigned long value, void *fixup_start, void *fixup_end) 98 { 99 struct fixup_entry *fcur, *fend; 100 101 fcur = fixup_start; 102 fend = fixup_end; 103 104 for (; fcur < fend; fcur++) { 105 if (patch_feature_section(value, fcur)) { 106 WARN_ON(1); 107 printk("Unable to patch feature section at %p - %p" \ 108 " with %p - %p\n", 109 calc_addr(fcur, fcur->start_off), 110 calc_addr(fcur, fcur->end_off), 111 calc_addr(fcur, fcur->alt_start_off), 112 calc_addr(fcur, fcur->alt_end_off)); 113 } 114 } 115 } 116 117 void do_lwsync_fixups(unsigned long value, void *fixup_start, void *fixup_end) 118 { 119 long *start, *end; 120 unsigned int *dest; 121 122 if (!(value & CPU_FTR_LWSYNC)) 123 return ; 124 125 start = fixup_start; 126 end = fixup_end; 127 128 for (; start < end; start++) { 129 dest = (void *)start + *start; 130 patch_instruction(dest, PPC_INST_LWSYNC); 131 } 132 } 133 134 static void do_final_fixups(void) 135 { 136 #if defined(CONFIG_PPC64) && defined(CONFIG_RELOCATABLE) 137 int *src, *dest; 138 unsigned long length; 139 140 if (PHYSICAL_START == 0) 141 return; 142 143 src = (int *)(KERNELBASE + PHYSICAL_START); 144 dest = (int *)KERNELBASE; 145 length = (__end_interrupts - _stext) / sizeof(int); 146 147 while (length--) { 148 patch_instruction(dest, *src); 149 src++; 150 dest++; 151 } 152 #endif 153 } 154 155 void apply_feature_fixups(void) 156 { 157 struct cpu_spec *spec = *PTRRELOC(&cur_cpu_spec); 158 159 /* 160 * Apply the CPU-specific and firmware specific fixups to kernel text 161 * (nop out sections not relevant to this CPU or this firmware). 162 */ 163 do_feature_fixups(spec->cpu_features, 164 PTRRELOC(&__start___ftr_fixup), 165 PTRRELOC(&__stop___ftr_fixup)); 166 167 do_feature_fixups(spec->mmu_features, 168 PTRRELOC(&__start___mmu_ftr_fixup), 169 PTRRELOC(&__stop___mmu_ftr_fixup)); 170 171 do_lwsync_fixups(spec->cpu_features, 172 PTRRELOC(&__start___lwsync_fixup), 173 PTRRELOC(&__stop___lwsync_fixup)); 174 175 #ifdef CONFIG_PPC64 176 do_feature_fixups(powerpc_firmware_features, 177 &__start___fw_ftr_fixup, &__stop___fw_ftr_fixup); 178 #endif 179 do_final_fixups(); 180 } 181 182 #ifdef CONFIG_FTR_FIXUP_SELFTEST 183 184 #define check(x) \ 185 if (!(x)) printk("feature-fixups: test failed at line %d\n", __LINE__); 186 187 /* This must be after the text it fixes up, vmlinux.lds.S enforces that atm */ 188 static struct fixup_entry fixup; 189 190 static long calc_offset(struct fixup_entry *entry, unsigned int *p) 191 { 192 return (unsigned long)p - (unsigned long)entry; 193 } 194 195 static void test_basic_patching(void) 196 { 197 extern unsigned int ftr_fixup_test1; 198 extern unsigned int end_ftr_fixup_test1; 199 extern unsigned int ftr_fixup_test1_orig; 200 extern unsigned int ftr_fixup_test1_expected; 201 int size = &end_ftr_fixup_test1 - &ftr_fixup_test1; 202 203 fixup.value = fixup.mask = 8; 204 fixup.start_off = calc_offset(&fixup, &ftr_fixup_test1 + 1); 205 fixup.end_off = calc_offset(&fixup, &ftr_fixup_test1 + 2); 206 fixup.alt_start_off = fixup.alt_end_off = 0; 207 208 /* Sanity check */ 209 check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_orig, size) == 0); 210 211 /* Check we don't patch if the value matches */ 212 patch_feature_section(8, &fixup); 213 check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_orig, size) == 0); 214 215 /* Check we do patch if the value doesn't match */ 216 patch_feature_section(0, &fixup); 217 check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_expected, size) == 0); 218 219 /* Check we do patch if the mask doesn't match */ 220 memcpy(&ftr_fixup_test1, &ftr_fixup_test1_orig, size); 221 check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_orig, size) == 0); 222 patch_feature_section(~8, &fixup); 223 check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_expected, size) == 0); 224 } 225 226 static void test_alternative_patching(void) 227 { 228 extern unsigned int ftr_fixup_test2; 229 extern unsigned int end_ftr_fixup_test2; 230 extern unsigned int ftr_fixup_test2_orig; 231 extern unsigned int ftr_fixup_test2_alt; 232 extern unsigned int ftr_fixup_test2_expected; 233 int size = &end_ftr_fixup_test2 - &ftr_fixup_test2; 234 235 fixup.value = fixup.mask = 0xF; 236 fixup.start_off = calc_offset(&fixup, &ftr_fixup_test2 + 1); 237 fixup.end_off = calc_offset(&fixup, &ftr_fixup_test2 + 2); 238 fixup.alt_start_off = calc_offset(&fixup, &ftr_fixup_test2_alt); 239 fixup.alt_end_off = calc_offset(&fixup, &ftr_fixup_test2_alt + 1); 240 241 /* Sanity check */ 242 check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_orig, size) == 0); 243 244 /* Check we don't patch if the value matches */ 245 patch_feature_section(0xF, &fixup); 246 check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_orig, size) == 0); 247 248 /* Check we do patch if the value doesn't match */ 249 patch_feature_section(0, &fixup); 250 check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_expected, size) == 0); 251 252 /* Check we do patch if the mask doesn't match */ 253 memcpy(&ftr_fixup_test2, &ftr_fixup_test2_orig, size); 254 check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_orig, size) == 0); 255 patch_feature_section(~0xF, &fixup); 256 check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_expected, size) == 0); 257 } 258 259 static void test_alternative_case_too_big(void) 260 { 261 extern unsigned int ftr_fixup_test3; 262 extern unsigned int end_ftr_fixup_test3; 263 extern unsigned int ftr_fixup_test3_orig; 264 extern unsigned int ftr_fixup_test3_alt; 265 int size = &end_ftr_fixup_test3 - &ftr_fixup_test3; 266 267 fixup.value = fixup.mask = 0xC; 268 fixup.start_off = calc_offset(&fixup, &ftr_fixup_test3 + 1); 269 fixup.end_off = calc_offset(&fixup, &ftr_fixup_test3 + 2); 270 fixup.alt_start_off = calc_offset(&fixup, &ftr_fixup_test3_alt); 271 fixup.alt_end_off = calc_offset(&fixup, &ftr_fixup_test3_alt + 2); 272 273 /* Sanity check */ 274 check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0); 275 276 /* Expect nothing to be patched, and the error returned to us */ 277 check(patch_feature_section(0xF, &fixup) == 1); 278 check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0); 279 check(patch_feature_section(0, &fixup) == 1); 280 check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0); 281 check(patch_feature_section(~0xF, &fixup) == 1); 282 check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0); 283 } 284 285 static void test_alternative_case_too_small(void) 286 { 287 extern unsigned int ftr_fixup_test4; 288 extern unsigned int end_ftr_fixup_test4; 289 extern unsigned int ftr_fixup_test4_orig; 290 extern unsigned int ftr_fixup_test4_alt; 291 extern unsigned int ftr_fixup_test4_expected; 292 int size = &end_ftr_fixup_test4 - &ftr_fixup_test4; 293 unsigned long flag; 294 295 /* Check a high-bit flag */ 296 flag = 1UL << ((sizeof(unsigned long) - 1) * 8); 297 fixup.value = fixup.mask = flag; 298 fixup.start_off = calc_offset(&fixup, &ftr_fixup_test4 + 1); 299 fixup.end_off = calc_offset(&fixup, &ftr_fixup_test4 + 5); 300 fixup.alt_start_off = calc_offset(&fixup, &ftr_fixup_test4_alt); 301 fixup.alt_end_off = calc_offset(&fixup, &ftr_fixup_test4_alt + 2); 302 303 /* Sanity check */ 304 check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_orig, size) == 0); 305 306 /* Check we don't patch if the value matches */ 307 patch_feature_section(flag, &fixup); 308 check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_orig, size) == 0); 309 310 /* Check we do patch if the value doesn't match */ 311 patch_feature_section(0, &fixup); 312 check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_expected, size) == 0); 313 314 /* Check we do patch if the mask doesn't match */ 315 memcpy(&ftr_fixup_test4, &ftr_fixup_test4_orig, size); 316 check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_orig, size) == 0); 317 patch_feature_section(~flag, &fixup); 318 check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_expected, size) == 0); 319 } 320 321 static void test_alternative_case_with_branch(void) 322 { 323 extern unsigned int ftr_fixup_test5; 324 extern unsigned int end_ftr_fixup_test5; 325 extern unsigned int ftr_fixup_test5_expected; 326 int size = &end_ftr_fixup_test5 - &ftr_fixup_test5; 327 328 check(memcmp(&ftr_fixup_test5, &ftr_fixup_test5_expected, size) == 0); 329 } 330 331 static void test_alternative_case_with_external_branch(void) 332 { 333 extern unsigned int ftr_fixup_test6; 334 extern unsigned int end_ftr_fixup_test6; 335 extern unsigned int ftr_fixup_test6_expected; 336 int size = &end_ftr_fixup_test6 - &ftr_fixup_test6; 337 338 check(memcmp(&ftr_fixup_test6, &ftr_fixup_test6_expected, size) == 0); 339 } 340 341 static void test_cpu_macros(void) 342 { 343 extern u8 ftr_fixup_test_FTR_macros; 344 extern u8 ftr_fixup_test_FTR_macros_expected; 345 unsigned long size = &ftr_fixup_test_FTR_macros_expected - 346 &ftr_fixup_test_FTR_macros; 347 348 /* The fixups have already been done for us during boot */ 349 check(memcmp(&ftr_fixup_test_FTR_macros, 350 &ftr_fixup_test_FTR_macros_expected, size) == 0); 351 } 352 353 static void test_fw_macros(void) 354 { 355 #ifdef CONFIG_PPC64 356 extern u8 ftr_fixup_test_FW_FTR_macros; 357 extern u8 ftr_fixup_test_FW_FTR_macros_expected; 358 unsigned long size = &ftr_fixup_test_FW_FTR_macros_expected - 359 &ftr_fixup_test_FW_FTR_macros; 360 361 /* The fixups have already been done for us during boot */ 362 check(memcmp(&ftr_fixup_test_FW_FTR_macros, 363 &ftr_fixup_test_FW_FTR_macros_expected, size) == 0); 364 #endif 365 } 366 367 static void test_lwsync_macros(void) 368 { 369 extern u8 lwsync_fixup_test; 370 extern u8 end_lwsync_fixup_test; 371 extern u8 lwsync_fixup_test_expected_LWSYNC; 372 extern u8 lwsync_fixup_test_expected_SYNC; 373 unsigned long size = &end_lwsync_fixup_test - 374 &lwsync_fixup_test; 375 376 /* The fixups have already been done for us during boot */ 377 if (cur_cpu_spec->cpu_features & CPU_FTR_LWSYNC) { 378 check(memcmp(&lwsync_fixup_test, 379 &lwsync_fixup_test_expected_LWSYNC, size) == 0); 380 } else { 381 check(memcmp(&lwsync_fixup_test, 382 &lwsync_fixup_test_expected_SYNC, size) == 0); 383 } 384 } 385 386 static int __init test_feature_fixups(void) 387 { 388 printk(KERN_DEBUG "Running feature fixup self-tests ...\n"); 389 390 test_basic_patching(); 391 test_alternative_patching(); 392 test_alternative_case_too_big(); 393 test_alternative_case_too_small(); 394 test_alternative_case_with_branch(); 395 test_alternative_case_with_external_branch(); 396 test_cpu_macros(); 397 test_fw_macros(); 398 test_lwsync_macros(); 399 400 return 0; 401 } 402 late_initcall(test_feature_fixups); 403 404 #endif /* CONFIG_FTR_FIXUP_SELFTEST */ 405