arch/powerpc/lib/feature-fixups.c

   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/jump_label.h>
  17 #include <linux/kernel.h>
  18 #include <linux/string.h>
  19 #include <linux/init.h>
  20 #include <linux/sched/mm.h>
  21 #include <asm/cputable.h>
  22 #include <asm/code-patching.h>
  23 #include <asm/page.h>
  24 #include <asm/sections.h>
  25 #include <asm/setup.h>
  26 #include <asm/firmware.h>
  27
  28 struct fixup_entry {
  29         unsigned long   mask;
  30         unsigned long   value;
  31         long            start_off;
  32         long            end_off;
  33         long            alt_start_off;
  34         long            alt_end_off;
  35 };
  36
  37 static unsigned int *calc_addr(struct fixup_entry *fcur, long offset)
  38 {
  39         /*
  40          * We store the offset to the code as a negative offset from
  41          * the start of the alt_entry, to support the VDSO. This
  42          * routine converts that back into an actual address.
  43          */
  44         return (unsigned int *)((unsigned long)fcur + offset);
  45 }
  46
  47 static int patch_alt_instruction(unsigned int *src, unsigned int *dest,
  48                                  unsigned int *alt_start, unsigned int *alt_end)
  49 {
  50         unsigned int instr;
  51
  52         instr = *src;
  53
  54         if (instr_is_relative_branch(*src)) {
  55                 unsigned int *target = (unsigned int *)branch_target(src);
  56
  57                 /* Branch within the section doesn't need translating */
  58                 if (target < alt_start || target >= alt_end) {
  59                         instr = translate_branch(dest, src);
  60                         if (!instr)
  61                                 return 1;
  62                 }
  63         }
  64
  65         patch_instruction(dest, instr);
  66
  67         return 0;
  68 }
  69
  70 static int patch_feature_section(unsigned long value, struct fixup_entry *fcur)
  71 {
  72         unsigned int *start, *end, *alt_start, *alt_end, *src, *dest;
  73
  74         start = calc_addr(fcur, fcur->start_off);
  75         end = calc_addr(fcur, fcur->end_off);
  76         alt_start = calc_addr(fcur, fcur->alt_start_off);
  77         alt_end = calc_addr(fcur, fcur->alt_end_off);
  78
  79         if ((alt_end - alt_start) > (end - start))
  80                 return 1;
  81
  82         if ((value & fcur->mask) == fcur->value)
  83                 return 0;
  84
  85         src = alt_start;
  86         dest = start;
  87
  88         for (; src < alt_end; src++, dest++) {
  89                 if (patch_alt_instruction(src, dest, alt_start, alt_end))
  90                         return 1;
  91         }
  92
  93         for (; dest < end; dest++)
  94                 patch_instruction(dest, PPC_INST_NOP);
  95
  96         return 0;
  97 }
  98
  99 void do_feature_fixups(unsigned long value, void *fixup_start, void *fixup_end)
 100 {
 101         struct fixup_entry *fcur, *fend;
 102
 103         fcur = fixup_start;
 104         fend = fixup_end;
 105
 106         for (; fcur < fend; fcur++) {
 107                 if (patch_feature_section(value, fcur)) {
 108                         WARN_ON(1);
 109                         printk("Unable to patch feature section at %p - %p" \
 110                                 " with %p - %p\n",
 111                                 calc_addr(fcur, fcur->start_off),
 112                                 calc_addr(fcur, fcur->end_off),
 113                                 calc_addr(fcur, fcur->alt_start_off),
 114                                 calc_addr(fcur, fcur->alt_end_off));
 115                 }
 116         }
 117 }
 118
 119 #ifdef CONFIG_PPC_BOOK3S_64
 120 void do_rfi_flush_fixups(enum l1d_flush_type types)
 121 {
 122         unsigned int instrs[3], *dest;
 123         long *start, *end;
 124         int i;
 125
 126         start = PTRRELOC(&__start___rfi_flush_fixup),
 127         end = PTRRELOC(&__stop___rfi_flush_fixup);
 128
 129         instrs[0] = 0x60000000; /* nop */
 130         instrs[1] = 0x60000000; /* nop */
 131         instrs[2] = 0x60000000; /* nop */
 132
 133         if (types & L1D_FLUSH_FALLBACK)
 134                 /* b .+16 to fallback flush */
 135                 instrs[0] = 0x48000010;
 136
 137         i = 0;
 138         if (types & L1D_FLUSH_ORI) {
 139                 instrs[i++] = 0x63ff0000; /* ori 31,31,0 speculation barrier */
 140                 instrs[i++] = 0x63de0000; /* ori 30,30,0 L1d flush*/
 141         }
 142
 143         if (types & L1D_FLUSH_MTTRIG)
 144                 instrs[i++] = 0x7c12dba6; /* mtspr TRIG2,r0 (SPR #882) */
 145
 146         for (i = 0; start < end; start++, i++) {
 147                 dest = (void *)start + *start;
 148
 149                 pr_devel("patching dest %lx\n", (unsigned long)dest);
 150
 151                 patch_instruction(dest, instrs[0]);
 152                 patch_instruction(dest + 1, instrs[1]);
 153                 patch_instruction(dest + 2, instrs[2]);
 154         }
 155
 156         printk(KERN_DEBUG "rfi-flush: patched %d locations\n", i);
 157 }
 158 #endif /* CONFIG_PPC_BOOK3S_64 */
 159
 160 void do_lwsync_fixups(unsigned long value, void *fixup_start, void *fixup_end)
 161 {
 162         long *start, *end;
 163         unsigned int *dest;
 164
 165         if (!(value & CPU_FTR_LWSYNC))
 166                 return ;
 167
 168         start = fixup_start;
 169         end = fixup_end;
 170
 171         for (; start < end; start++) {
 172                 dest = (void *)start + *start;
 173                 patch_instruction(dest, PPC_INST_LWSYNC);
 174         }
 175 }
 176
 177 static void do_final_fixups(void)
 178 {
 179 #if defined(CONFIG_PPC64) && defined(CONFIG_RELOCATABLE)
 180         int *src, *dest;
 181         unsigned long length;
 182
 183         if (PHYSICAL_START == 0)
 184                 return;
 185
 186         src = (int *)(KERNELBASE + PHYSICAL_START);
 187         dest = (int *)KERNELBASE;
 188         length = (__end_interrupts - _stext) / sizeof(int);
 189
 190         while (length--) {
 191                 patch_instruction(dest, *src);
 192                 src++;
 193                 dest++;
 194         }
 195 #endif
 196 }
 197
 198 static unsigned long __initdata saved_cpu_features;
 199 static unsigned int __initdata saved_mmu_features;
 200 #ifdef CONFIG_PPC64
 201 static unsigned long __initdata saved_firmware_features;
 202 #endif
 203
 204 void __init apply_feature_fixups(void)
 205 {
 206         struct cpu_spec *spec = PTRRELOC(*PTRRELOC(&cur_cpu_spec));
 207
 208         *PTRRELOC(&saved_cpu_features) = spec->cpu_features;
 209         *PTRRELOC(&saved_mmu_features) = spec->mmu_features;
 210
 211         /*
 212          * Apply the CPU-specific and firmware specific fixups to kernel text
 213          * (nop out sections not relevant to this CPU or this firmware).
 214          */
 215         do_feature_fixups(spec->cpu_features,
 216                           PTRRELOC(&__start___ftr_fixup),
 217                           PTRRELOC(&__stop___ftr_fixup));
 218
 219         do_feature_fixups(spec->mmu_features,
 220                           PTRRELOC(&__start___mmu_ftr_fixup),
 221                           PTRRELOC(&__stop___mmu_ftr_fixup));
 222
 223         do_lwsync_fixups(spec->cpu_features,
 224                          PTRRELOC(&__start___lwsync_fixup),
 225                          PTRRELOC(&__stop___lwsync_fixup));
 226
 227 #ifdef CONFIG_PPC64
 228         saved_firmware_features = powerpc_firmware_features;
 229         do_feature_fixups(powerpc_firmware_features,
 230                           &__start___fw_ftr_fixup, &__stop___fw_ftr_fixup);
 231 #endif
 232         do_final_fixups();
 233 }
 234
 235 void __init setup_feature_keys(void)
 236 {
 237         /*
 238          * Initialise jump label. This causes all the cpu/mmu_has_feature()
 239          * checks to take on their correct polarity based on the current set of
 240          * CPU/MMU features.
 241          */
 242         jump_label_init();
 243         cpu_feature_keys_init();
 244         mmu_feature_keys_init();
 245 }
 246
 247 static int __init check_features(void)
 248 {
 249         WARN(saved_cpu_features != cur_cpu_spec->cpu_features,
 250              "CPU features changed after feature patching!\n");
 251         WARN(saved_mmu_features != cur_cpu_spec->mmu_features,
 252              "MMU features changed after feature patching!\n");
 253 #ifdef CONFIG_PPC64
 254         WARN(saved_firmware_features != powerpc_firmware_features,
 255              "Firmware features changed after feature patching!\n");
 256 #endif
 257
 258         return 0;
 259 }
 260 late_initcall(check_features);
 261
 262 #ifdef CONFIG_FTR_FIXUP_SELFTEST
 263
 264 #define check(x)        \
 265         if (!(x)) printk("feature-fixups: test failed at line %d\n", __LINE__);
 266
 267 /* This must be after the text it fixes up, vmlinux.lds.S enforces that atm */
 268 static struct fixup_entry fixup;
 269
 270 static long calc_offset(struct fixup_entry *entry, unsigned int *p)
 271 {
 272         return (unsigned long)p - (unsigned long)entry;
 273 }
 274
 275 static void test_basic_patching(void)
 276 {
 277         extern unsigned int ftr_fixup_test1[];
 278         extern unsigned int end_ftr_fixup_test1[];
 279         extern unsigned int ftr_fixup_test1_orig[];
 280         extern unsigned int ftr_fixup_test1_expected[];
 281         int size = end_ftr_fixup_test1 - ftr_fixup_test1;
 282
 283         fixup.value = fixup.mask = 8;
 284         fixup.start_off = calc_offset(&fixup, ftr_fixup_test1 + 1);
 285         fixup.end_off = calc_offset(&fixup, ftr_fixup_test1 + 2);
 286         fixup.alt_start_off = fixup.alt_end_off = 0;
 287
 288         /* Sanity check */
 289         check(memcmp(ftr_fixup_test1, ftr_fixup_test1_orig, size) == 0);
 290
 291         /* Check we don't patch if the value matches */
 292         patch_feature_section(8, &fixup);
 293         check(memcmp(ftr_fixup_test1, ftr_fixup_test1_orig, size) == 0);
 294
 295         /* Check we do patch if the value doesn't match */
 296         patch_feature_section(0, &fixup);
 297         check(memcmp(ftr_fixup_test1, ftr_fixup_test1_expected, size) == 0);
 298
 299         /* Check we do patch if the mask doesn't match */
 300         memcpy(ftr_fixup_test1, ftr_fixup_test1_orig, size);
 301         check(memcmp(ftr_fixup_test1, ftr_fixup_test1_orig, size) == 0);
 302         patch_feature_section(~8, &fixup);
 303         check(memcmp(ftr_fixup_test1, ftr_fixup_test1_expected, size) == 0);
 304 }
 305
 306 static void test_alternative_patching(void)
 307 {
 308         extern unsigned int ftr_fixup_test2[];
 309         extern unsigned int end_ftr_fixup_test2[];
 310         extern unsigned int ftr_fixup_test2_orig[];
 311         extern unsigned int ftr_fixup_test2_alt[];
 312         extern unsigned int ftr_fixup_test2_expected[];
 313         int size = end_ftr_fixup_test2 - ftr_fixup_test2;
 314
 315         fixup.value = fixup.mask = 0xF;
 316         fixup.start_off = calc_offset(&fixup, ftr_fixup_test2 + 1);
 317         fixup.end_off = calc_offset(&fixup, ftr_fixup_test2 + 2);
 318         fixup.alt_start_off = calc_offset(&fixup, ftr_fixup_test2_alt);
 319         fixup.alt_end_off = calc_offset(&fixup, ftr_fixup_test2_alt + 1);
 320
 321         /* Sanity check */
 322         check(memcmp(ftr_fixup_test2, ftr_fixup_test2_orig, size) == 0);
 323
 324         /* Check we don't patch if the value matches */
 325         patch_feature_section(0xF, &fixup);
 326         check(memcmp(ftr_fixup_test2, ftr_fixup_test2_orig, size) == 0);
 327
 328         /* Check we do patch if the value doesn't match */
 329         patch_feature_section(0, &fixup);
 330         check(memcmp(ftr_fixup_test2, ftr_fixup_test2_expected, size) == 0);
 331
 332         /* Check we do patch if the mask doesn't match */
 333         memcpy(ftr_fixup_test2, ftr_fixup_test2_orig, size);
 334         check(memcmp(ftr_fixup_test2, ftr_fixup_test2_orig, size) == 0);
 335         patch_feature_section(~0xF, &fixup);
 336         check(memcmp(ftr_fixup_test2, ftr_fixup_test2_expected, size) == 0);
 337 }
 338
 339 static void test_alternative_case_too_big(void)
 340 {
 341         extern unsigned int ftr_fixup_test3[];
 342         extern unsigned int end_ftr_fixup_test3[];
 343         extern unsigned int ftr_fixup_test3_orig[];
 344         extern unsigned int ftr_fixup_test3_alt[];
 345         int size = end_ftr_fixup_test3 - ftr_fixup_test3;
 346
 347         fixup.value = fixup.mask = 0xC;
 348         fixup.start_off = calc_offset(&fixup, ftr_fixup_test3 + 1);
 349         fixup.end_off = calc_offset(&fixup, ftr_fixup_test3 + 2);
 350         fixup.alt_start_off = calc_offset(&fixup, ftr_fixup_test3_alt);
 351         fixup.alt_end_off = calc_offset(&fixup, ftr_fixup_test3_alt + 2);
 352
 353         /* Sanity check */
 354         check(memcmp(ftr_fixup_test3, ftr_fixup_test3_orig, size) == 0);
 355
 356         /* Expect nothing to be patched, and the error returned to us */
 357         check(patch_feature_section(0xF, &fixup) == 1);
 358         check(memcmp(ftr_fixup_test3, ftr_fixup_test3_orig, size) == 0);
 359         check(patch_feature_section(0, &fixup) == 1);
 360         check(memcmp(ftr_fixup_test3, ftr_fixup_test3_orig, size) == 0);
 361         check(patch_feature_section(~0xF, &fixup) == 1);
 362         check(memcmp(ftr_fixup_test3, ftr_fixup_test3_orig, size) == 0);
 363 }
 364
 365 static void test_alternative_case_too_small(void)
 366 {
 367         extern unsigned int ftr_fixup_test4[];
 368         extern unsigned int end_ftr_fixup_test4[];
 369         extern unsigned int ftr_fixup_test4_orig[];
 370         extern unsigned int ftr_fixup_test4_alt[];
 371         extern unsigned int ftr_fixup_test4_expected[];
 372         int size = end_ftr_fixup_test4 - ftr_fixup_test4;
 373         unsigned long flag;
 374
 375         /* Check a high-bit flag */
 376         flag = 1UL << ((sizeof(unsigned long) - 1) * 8);
 377         fixup.value = fixup.mask = flag;
 378         fixup.start_off = calc_offset(&fixup, ftr_fixup_test4 + 1);
 379         fixup.end_off = calc_offset(&fixup, ftr_fixup_test4 + 5);
 380         fixup.alt_start_off = calc_offset(&fixup, ftr_fixup_test4_alt);
 381         fixup.alt_end_off = calc_offset(&fixup, ftr_fixup_test4_alt + 2);
 382
 383         /* Sanity check */
 384         check(memcmp(ftr_fixup_test4, ftr_fixup_test4_orig, size) == 0);
 385
 386         /* Check we don't patch if the value matches */
 387         patch_feature_section(flag, &fixup);
 388         check(memcmp(ftr_fixup_test4, ftr_fixup_test4_orig, size) == 0);
 389
 390         /* Check we do patch if the value doesn't match */
 391         patch_feature_section(0, &fixup);
 392         check(memcmp(ftr_fixup_test4, ftr_fixup_test4_expected, size) == 0);
 393
 394         /* Check we do patch if the mask doesn't match */
 395         memcpy(ftr_fixup_test4, ftr_fixup_test4_orig, size);
 396         check(memcmp(ftr_fixup_test4, ftr_fixup_test4_orig, size) == 0);
 397         patch_feature_section(~flag, &fixup);
 398         check(memcmp(ftr_fixup_test4, ftr_fixup_test4_expected, size) == 0);
 399 }
 400
 401 static void test_alternative_case_with_branch(void)
 402 {
 403         extern unsigned int ftr_fixup_test5[];
 404         extern unsigned int end_ftr_fixup_test5[];
 405         extern unsigned int ftr_fixup_test5_expected[];
 406         int size = end_ftr_fixup_test5 - ftr_fixup_test5;
 407
 408         check(memcmp(ftr_fixup_test5, ftr_fixup_test5_expected, size) == 0);
 409 }
 410
 411 static void test_alternative_case_with_external_branch(void)
 412 {
 413         extern unsigned int ftr_fixup_test6[];
 414         extern unsigned int end_ftr_fixup_test6[];
 415         extern unsigned int ftr_fixup_test6_expected[];
 416         int size = end_ftr_fixup_test6 - ftr_fixup_test6;
 417
 418         check(memcmp(ftr_fixup_test6, ftr_fixup_test6_expected, size) == 0);
 419 }
 420
 421 static void test_cpu_macros(void)
 422 {
 423         extern u8 ftr_fixup_test_FTR_macros[];
 424         extern u8 ftr_fixup_test_FTR_macros_expected[];
 425         unsigned long size = ftr_fixup_test_FTR_macros_expected -
 426                              ftr_fixup_test_FTR_macros;
 427
 428         /* The fixups have already been done for us during boot */
 429         check(memcmp(ftr_fixup_test_FTR_macros,
 430                      ftr_fixup_test_FTR_macros_expected, size) == 0);
 431 }
 432
 433 static void test_fw_macros(void)
 434 {
 435 #ifdef CONFIG_PPC64
 436         extern u8 ftr_fixup_test_FW_FTR_macros[];
 437         extern u8 ftr_fixup_test_FW_FTR_macros_expected[];
 438         unsigned long size = ftr_fixup_test_FW_FTR_macros_expected -
 439                              ftr_fixup_test_FW_FTR_macros;
 440
 441         /* The fixups have already been done for us during boot */
 442         check(memcmp(ftr_fixup_test_FW_FTR_macros,
 443                      ftr_fixup_test_FW_FTR_macros_expected, size) == 0);
 444 #endif
 445 }
 446
 447 static void test_lwsync_macros(void)
 448 {
 449         extern u8 lwsync_fixup_test[];
 450         extern u8 end_lwsync_fixup_test[];
 451         extern u8 lwsync_fixup_test_expected_LWSYNC[];
 452         extern u8 lwsync_fixup_test_expected_SYNC[];
 453         unsigned long size = end_lwsync_fixup_test -
 454                              lwsync_fixup_test;
 455
 456         /* The fixups have already been done for us during boot */
 457         if (cur_cpu_spec->cpu_features & CPU_FTR_LWSYNC) {
 458                 check(memcmp(lwsync_fixup_test,
 459                              lwsync_fixup_test_expected_LWSYNC, size) == 0);
 460         } else {
 461                 check(memcmp(lwsync_fixup_test,
 462                              lwsync_fixup_test_expected_SYNC, size) == 0);
 463         }
 464 }
 465
 466 static int __init test_feature_fixups(void)
 467 {
 468         printk(KERN_DEBUG "Running feature fixup self-tests ...\n");
 469
 470         test_basic_patching();
 471         test_alternative_patching();
 472         test_alternative_case_too_big();
 473         test_alternative_case_too_small();
 474         test_alternative_case_with_branch();
 475         test_alternative_case_with_external_branch();
 476         test_cpu_macros();
 477         test_fw_macros();
 478         test_lwsync_macros();
 479
 480         return 0;
 481 }
 482 late_initcall(test_feature_fixups);
 483
 484 #endif /* CONFIG_FTR_FIXUP_SELFTEST */