1// SPDX-License-Identifier: GPL-2.0 2/* 3 * Code for replacing ftrace calls with jumps. 4 * 5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> 6 * 7 * Thanks goes out to P.A. Semi, Inc for supplying me with a PPC64 box. 8 * 9 * Added function graph tracer code, taken from x86 that was written 10 * by Frederic Weisbecker, and ported to PPC by Steven Rostedt. 11 * 12 */ 13 14#define pr_fmt(fmt) "ftrace-powerpc: " fmt 15 16#include <linux/spinlock.h> 17#include <linux/hardirq.h> 18#include <linux/uaccess.h> 19#include <linux/module.h> 20#include <linux/ftrace.h> 21#include <linux/percpu.h> 22#include <linux/init.h> 23#include <linux/list.h> 24 25#include <asm/cacheflush.h> 26#include <asm/code-patching.h> 27#include <asm/ftrace.h> 28#include <asm/syscall.h> 29#include <asm/inst.h> 30 31/* 32 * We generally only have a single long_branch tramp and at most 2 or 3 plt 33 * tramps generated. But, we don't use the plt tramps currently. We also allot 34 * 2 tramps after .text and .init.text. So, we only end up with around 3 usable 35 * tramps in total. Set aside 8 just to be sure. 36 */ 37#define NUM_FTRACE_TRAMPS 8 38static unsigned long ftrace_tramps[NUM_FTRACE_TRAMPS]; 39 40unsigned long ftrace_call_adjust(unsigned long addr) 41{ 42 return addr; 43} 44 45static ppc_inst_t 46ftrace_call_replace(unsigned long ip, unsigned long addr, int link) 47{ 48 ppc_inst_t op; 49 50 addr = ppc_function_entry((void *)addr); 51 52 /* if (link) set op to 'bl' else 'b' */ 53 create_branch(&op, (u32 *)ip, addr, link ? BRANCH_SET_LINK : 0); 54 55 return op; 56} 57 58static inline int 59ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_t new) 60{ 61 ppc_inst_t replaced; 62 63 /* 64 * Note: 65 * We are paranoid about modifying text, as if a bug was to happen, it 66 * could cause us to read or write to someplace that could cause harm. 67 * Carefully read and modify the code with probe_kernel_*(), and make 68 * sure what we read is what we expected it to be before modifying it. 69 */ 70 71 /* read the text we want to modify */ 72 if (copy_inst_from_kernel_nofault(&replaced, (void *)ip)) 73 return -EFAULT; 74 75 /* Make sure it is what we expect it to be */ 76 if (!ppc_inst_equal(replaced, old)) { 77 pr_err("%p: replaced (%08lx) != old (%08lx)", (void *)ip, 78 ppc_inst_as_ulong(replaced), ppc_inst_as_ulong(old)); 79 return -EINVAL; 80 } 81 82 /* replace the text with the new text */ 83 return patch_instruction((u32 *)ip, new); 84} 85 86/* 87 * Helper functions that are the same for both PPC64 and PPC32. 88 */ 89static int test_24bit_addr(unsigned long ip, unsigned long addr) 90{ 91 addr = ppc_function_entry((void *)addr); 92 93 return is_offset_in_branch_range(addr - ip); 94} 95 96static int is_bl_op(ppc_inst_t op) 97{ 98 return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BL(0); 99} 100 101static int is_b_op(ppc_inst_t op) 102{ 103 return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BRANCH(0); 104} 105 106static unsigned long find_bl_target(unsigned long ip, ppc_inst_t op) 107{ 108 int offset; 109 110 offset = PPC_LI(ppc_inst_val(op)); 111 /* make it signed */ 112 if (offset & 0x02000000) 113 offset |= 0xfe000000; 114 115 return ip + (long)offset; 116} 117 118#ifdef CONFIG_MODULES 119static int 120__ftrace_make_nop(struct module *mod, 121 struct dyn_ftrace *rec, unsigned long addr) 122{ 123 unsigned long entry, ptr, tramp; 124 unsigned long ip = rec->ip; 125 ppc_inst_t op, pop; 126 127 /* read where this goes */ 128 if (copy_inst_from_kernel_nofault(&op, (void *)ip)) { 129 pr_err("Fetching opcode failed.\n"); 130 return -EFAULT; 131 } 132 133 /* Make sure that this is still a 24bit jump */ 134 if (!is_bl_op(op)) { 135 pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(op)); 136 return -EINVAL; 137 } 138 139 /* lets find where the pointer goes */ 140 tramp = find_bl_target(ip, op); 141 142 pr_devel("ip:%lx jumps to %lx", ip, tramp); 143 144 if (module_trampoline_target(mod, tramp, &ptr)) { 145 pr_err("Failed to get trampoline target\n"); 146 return -EFAULT; 147 } 148 149 pr_devel("trampoline target %lx", ptr); 150 151 entry = ppc_global_function_entry((void *)addr); 152 /* This should match what was called */ 153 if (ptr != entry) { 154 pr_err("addr %lx does not match expected %lx\n", ptr, entry); 155 return -EINVAL; 156 } 157 158 if (IS_ENABLED(CONFIG_MPROFILE_KERNEL)) { 159 if (copy_inst_from_kernel_nofault(&op, (void *)(ip - 4))) { 160 pr_err("Fetching instruction at %lx failed.\n", ip - 4); 161 return -EFAULT; 162 } 163 164 /* We expect either a mflr r0, or a std r0, LRSAVE(r1) */ 165 if (!ppc_inst_equal(op, ppc_inst(PPC_RAW_MFLR(_R0))) && 166 !ppc_inst_equal(op, ppc_inst(PPC_INST_STD_LR))) { 167 pr_err("Unexpected instruction %08lx around bl _mcount\n", 168 ppc_inst_as_ulong(op)); 169 return -EINVAL; 170 } 171 } else if (IS_ENABLED(CONFIG_PPC64)) { 172 /* 173 * Check what is in the next instruction. We can see ld r2,40(r1), but 174 * on first pass after boot we will see mflr r0. 175 */ 176 if (copy_inst_from_kernel_nofault(&op, (void *)(ip + 4))) { 177 pr_err("Fetching op failed.\n"); 178 return -EFAULT; 179 } 180 181 if (!ppc_inst_equal(op, ppc_inst(PPC_INST_LD_TOC))) { 182 pr_err("Expected %08lx found %08lx\n", PPC_INST_LD_TOC, 183 ppc_inst_as_ulong(op)); 184 return -EINVAL; 185 } 186 } 187 188 /* 189 * When using -mprofile-kernel or PPC32 there is no load to jump over. 190 * 191 * Otherwise our original call site looks like: 192 * 193 * bl <tramp> 194 * ld r2,XX(r1) 195 * 196 * Milton Miller pointed out that we can not simply nop the branch. 197 * If a task was preempted when calling a trace function, the nops 198 * will remove the way to restore the TOC in r2 and the r2 TOC will 199 * get corrupted. 200 * 201 * Use a b +8 to jump over the load. 202 */ 203 if (IS_ENABLED(CONFIG_MPROFILE_KERNEL) || IS_ENABLED(CONFIG_PPC32)) 204 pop = ppc_inst(PPC_RAW_NOP()); 205 else 206 pop = ppc_inst(PPC_RAW_BRANCH(8)); /* b +8 */ 207 208 if (patch_instruction((u32 *)ip, pop)) { 209 pr_err("Patching NOP failed.\n"); 210 return -EPERM; 211 } 212 213 return 0; 214} 215#else 216static int __ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) 217{ 218 return 0; 219} 220#endif /* CONFIG_MODULES */ 221 222static unsigned long find_ftrace_tramp(unsigned long ip) 223{ 224 int i; 225 226 /* 227 * We have the compiler generated long_branch tramps at the end 228 * and we prefer those 229 */ 230 for (i = NUM_FTRACE_TRAMPS - 1; i >= 0; i--) 231 if (!ftrace_tramps[i]) 232 continue; 233 else if (is_offset_in_branch_range(ftrace_tramps[i] - ip)) 234 return ftrace_tramps[i]; 235 236 return 0; 237} 238 239static int add_ftrace_tramp(unsigned long tramp) 240{ 241 int i; 242 243 for (i = 0; i < NUM_FTRACE_TRAMPS; i++) 244 if (!ftrace_tramps[i]) { 245 ftrace_tramps[i] = tramp; 246 return 0; 247 } 248 249 return -1; 250} 251 252/* 253 * If this is a compiler generated long_branch trampoline (essentially, a 254 * trampoline that has a branch to _mcount()), we re-write the branch to 255 * instead go to ftrace_[regs_]caller() and note down the location of this 256 * trampoline. 257 */ 258static int setup_mcount_compiler_tramp(unsigned long tramp) 259{ 260 int i; 261 ppc_inst_t op; 262 unsigned long ptr; 263 264 /* Is this a known long jump tramp? */ 265 for (i = 0; i < NUM_FTRACE_TRAMPS; i++) 266 if (ftrace_tramps[i] == tramp) 267 return 0; 268 269 /* New trampoline -- read where this goes */ 270 if (copy_inst_from_kernel_nofault(&op, (void *)tramp)) { 271 pr_debug("Fetching opcode failed.\n"); 272 return -1; 273 } 274 275 /* Is this a 24 bit branch? */ 276 if (!is_b_op(op)) { 277 pr_debug("Trampoline is not a long branch tramp.\n"); 278 return -1; 279 } 280 281 /* lets find where the pointer goes */ 282 ptr = find_bl_target(tramp, op); 283 284 if (ptr != ppc_global_function_entry((void *)_mcount)) { 285 pr_debug("Trampoline target %p is not _mcount\n", (void *)ptr); 286 return -1; 287 } 288 289 /* Let's re-write the tramp to go to ftrace_[regs_]caller */ 290 if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) 291 ptr = ppc_global_function_entry((void *)ftrace_regs_caller); 292 else 293 ptr = ppc_global_function_entry((void *)ftrace_caller); 294 295 if (patch_branch((u32 *)tramp, ptr, 0)) { 296 pr_debug("REL24 out of range!\n"); 297 return -1; 298 } 299 300 if (add_ftrace_tramp(tramp)) { 301 pr_debug("No tramp locations left\n"); 302 return -1; 303 } 304 305 return 0; 306} 307 308static int __ftrace_make_nop_kernel(struct dyn_ftrace *rec, unsigned long addr) 309{ 310 unsigned long tramp, ip = rec->ip; 311 ppc_inst_t op; 312 313 /* Read where this goes */ 314 if (copy_inst_from_kernel_nofault(&op, (void *)ip)) { 315 pr_err("Fetching opcode failed.\n"); 316 return -EFAULT; 317 } 318 319 /* Make sure that this is still a 24bit jump */ 320 if (!is_bl_op(op)) { 321 pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(op)); 322 return -EINVAL; 323 } 324 325 /* Let's find where the pointer goes */ 326 tramp = find_bl_target(ip, op); 327 328 pr_devel("ip:%lx jumps to %lx", ip, tramp); 329 330 if (setup_mcount_compiler_tramp(tramp)) { 331 /* Are other trampolines reachable? */ 332 if (!find_ftrace_tramp(ip)) { 333 pr_err("No ftrace trampolines reachable from %ps\n", 334 (void *)ip); 335 return -EINVAL; 336 } 337 } 338 339 if (patch_instruction((u32 *)ip, ppc_inst(PPC_RAW_NOP()))) { 340 pr_err("Patching NOP failed.\n"); 341 return -EPERM; 342 } 343 344 return 0; 345} 346 347int ftrace_make_nop(struct module *mod, 348 struct dyn_ftrace *rec, unsigned long addr) 349{ 350 unsigned long ip = rec->ip; 351 ppc_inst_t old, new; 352 353 /* 354 * If the calling address is more that 24 bits away, 355 * then we had to use a trampoline to make the call. 356 * Otherwise just update the call site. 357 */ 358 if (test_24bit_addr(ip, addr)) { 359 /* within range */ 360 old = ftrace_call_replace(ip, addr, 1); 361 new = ppc_inst(PPC_RAW_NOP()); 362 return ftrace_modify_code(ip, old, new); 363 } else if (core_kernel_text(ip)) { 364 return __ftrace_make_nop_kernel(rec, addr); 365 } else if (!IS_ENABLED(CONFIG_MODULES)) { 366 return -EINVAL; 367 } 368 369 /* 370 * Out of range jumps are called from modules. 371 * We should either already have a pointer to the module 372 * or it has been passed in. 373 */ 374 if (!rec->arch.mod) { 375 if (!mod) { 376 pr_err("No module loaded addr=%lx\n", addr); 377 return -EFAULT; 378 } 379 rec->arch.mod = mod; 380 } else if (mod) { 381 if (mod != rec->arch.mod) { 382 pr_err("Record mod %p not equal to passed in mod %p\n", 383 rec->arch.mod, mod); 384 return -EINVAL; 385 } 386 /* nothing to do if mod == rec->arch.mod */ 387 } else 388 mod = rec->arch.mod; 389 390 return __ftrace_make_nop(mod, rec, addr); 391} 392 393#ifdef CONFIG_MODULES 394/* 395 * Examine the existing instructions for __ftrace_make_call. 396 * They should effectively be a NOP, and follow formal constraints, 397 * depending on the ABI. Return false if they don't. 398 */ 399static bool expected_nop_sequence(void *ip, ppc_inst_t op0, ppc_inst_t op1) 400{ 401 if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) 402 return ppc_inst_equal(op0, ppc_inst(PPC_RAW_NOP())); 403 else 404 return ppc_inst_equal(op0, ppc_inst(PPC_RAW_BRANCH(8))) && 405 ppc_inst_equal(op1, ppc_inst(PPC_INST_LD_TOC)); 406} 407 408static int 409__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) 410{ 411 ppc_inst_t op[2]; 412 void *ip = (void *)rec->ip; 413 unsigned long entry, ptr, tramp; 414 struct module *mod = rec->arch.mod; 415 416 /* read where this goes */ 417 if (copy_inst_from_kernel_nofault(op, ip)) 418 return -EFAULT; 419 420 if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && 421 copy_inst_from_kernel_nofault(op + 1, ip + 4)) 422 return -EFAULT; 423 424 if (!expected_nop_sequence(ip, op[0], op[1])) { 425 pr_err("Unexpected call sequence at %p: %08lx %08lx\n", ip, 426 ppc_inst_as_ulong(op[0]), ppc_inst_as_ulong(op[1])); 427 return -EINVAL; 428 } 429 430 /* If we never set up ftrace trampoline(s), then bail */ 431 if (!mod->arch.tramp || 432 (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !mod->arch.tramp_regs)) { 433 pr_err("No ftrace trampoline\n"); 434 return -EINVAL; 435 } 436 437 if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && rec->flags & FTRACE_FL_REGS) 438 tramp = mod->arch.tramp_regs; 439 else 440 tramp = mod->arch.tramp; 441 442 if (module_trampoline_target(mod, tramp, &ptr)) { 443 pr_err("Failed to get trampoline target\n"); 444 return -EFAULT; 445 } 446 447 pr_devel("trampoline target %lx", ptr); 448 449 entry = ppc_global_function_entry((void *)addr); 450 /* This should match what was called */ 451 if (ptr != entry) { 452 pr_err("addr %lx does not match expected %lx\n", ptr, entry); 453 return -EINVAL; 454 } 455 456 if (patch_branch(ip, tramp, BRANCH_SET_LINK)) { 457 pr_err("REL24 out of range!\n"); 458 return -EINVAL; 459 } 460 461 return 0; 462} 463#else 464static int __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) 465{ 466 return 0; 467} 468#endif /* CONFIG_MODULES */ 469 470static int __ftrace_make_call_kernel(struct dyn_ftrace *rec, unsigned long addr) 471{ 472 ppc_inst_t op; 473 void *ip = (void *)rec->ip; 474 unsigned long tramp, entry, ptr; 475 476 /* Make sure we're being asked to patch branch to a known ftrace addr */ 477 entry = ppc_global_function_entry((void *)ftrace_caller); 478 ptr = ppc_global_function_entry((void *)addr); 479 480 if (ptr != entry && IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) 481 entry = ppc_global_function_entry((void *)ftrace_regs_caller); 482 483 if (ptr != entry) { 484 pr_err("Unknown ftrace addr to patch: %ps\n", (void *)ptr); 485 return -EINVAL; 486 } 487 488 /* Make sure we have a nop */ 489 if (copy_inst_from_kernel_nofault(&op, ip)) { 490 pr_err("Unable to read ftrace location %p\n", ip); 491 return -EFAULT; 492 } 493 494 if (!ppc_inst_equal(op, ppc_inst(PPC_RAW_NOP()))) { 495 pr_err("Unexpected call sequence at %p: %08lx\n", 496 ip, ppc_inst_as_ulong(op)); 497 return -EINVAL; 498 } 499 500 tramp = find_ftrace_tramp((unsigned long)ip); 501 if (!tramp) { 502 pr_err("No ftrace trampolines reachable from %ps\n", ip); 503 return -EINVAL; 504 } 505 506 if (patch_branch(ip, tramp, BRANCH_SET_LINK)) { 507 pr_err("Error patching branch to ftrace tramp!\n"); 508 return -EINVAL; 509 } 510 511 return 0; 512} 513 514int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) 515{ 516 unsigned long ip = rec->ip; 517 ppc_inst_t old, new; 518 519 /* 520 * If the calling address is more that 24 bits away, 521 * then we had to use a trampoline to make the call. 522 * Otherwise just update the call site. 523 */ 524 if (test_24bit_addr(ip, addr)) { 525 /* within range */ 526 old = ppc_inst(PPC_RAW_NOP()); 527 new = ftrace_call_replace(ip, addr, 1); 528 return ftrace_modify_code(ip, old, new); 529 } else if (core_kernel_text(ip)) { 530 return __ftrace_make_call_kernel(rec, addr); 531 } else if (!IS_ENABLED(CONFIG_MODULES)) { 532 /* We should not get here without modules */ 533 return -EINVAL; 534 } 535 536 /* 537 * Out of range jumps are called from modules. 538 * Being that we are converting from nop, it had better 539 * already have a module defined. 540 */ 541 if (!rec->arch.mod) { 542 pr_err("No module loaded\n"); 543 return -EINVAL; 544 } 545 546 return __ftrace_make_call(rec, addr); 547} 548 549#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 550#ifdef CONFIG_MODULES 551static int 552__ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, 553 unsigned long addr) 554{ 555 ppc_inst_t op; 556 unsigned long ip = rec->ip; 557 unsigned long entry, ptr, tramp; 558 struct module *mod = rec->arch.mod; 559 560 /* If we never set up ftrace trampolines, then bail */ 561 if (!mod->arch.tramp || !mod->arch.tramp_regs) { 562 pr_err("No ftrace trampoline\n"); 563 return -EINVAL; 564 } 565 566 /* read where this goes */ 567 if (copy_inst_from_kernel_nofault(&op, (void *)ip)) { 568 pr_err("Fetching opcode failed.\n"); 569 return -EFAULT; 570 } 571 572 /* Make sure that this is still a 24bit jump */ 573 if (!is_bl_op(op)) { 574 pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(op)); 575 return -EINVAL; 576 } 577 578 /* lets find where the pointer goes */ 579 tramp = find_bl_target(ip, op); 580 entry = ppc_global_function_entry((void *)old_addr); 581 582 pr_devel("ip:%lx jumps to %lx", ip, tramp); 583 584 if (tramp != entry) { 585 /* old_addr is not within range, so we must have used a trampoline */ 586 if (module_trampoline_target(mod, tramp, &ptr)) { 587 pr_err("Failed to get trampoline target\n"); 588 return -EFAULT; 589 } 590 591 pr_devel("trampoline target %lx", ptr); 592 593 /* This should match what was called */ 594 if (ptr != entry) { 595 pr_err("addr %lx does not match expected %lx\n", ptr, entry); 596 return -EINVAL; 597 } 598 } 599 600 /* The new target may be within range */ 601 if (test_24bit_addr(ip, addr)) { 602 /* within range */ 603 if (patch_branch((u32 *)ip, addr, BRANCH_SET_LINK)) { 604 pr_err("REL24 out of range!\n"); 605 return -EINVAL; 606 } 607 608 return 0; 609 } 610 611 if (rec->flags & FTRACE_FL_REGS) 612 tramp = mod->arch.tramp_regs; 613 else 614 tramp = mod->arch.tramp; 615 616 if (module_trampoline_target(mod, tramp, &ptr)) { 617 pr_err("Failed to get trampoline target\n"); 618 return -EFAULT; 619 } 620 621 pr_devel("trampoline target %lx", ptr); 622 623 entry = ppc_global_function_entry((void *)addr); 624 /* This should match what was called */ 625 if (ptr != entry) { 626 pr_err("addr %lx does not match expected %lx\n", ptr, entry); 627 return -EINVAL; 628 } 629 630 if (patch_branch((u32 *)ip, tramp, BRANCH_SET_LINK)) { 631 pr_err("REL24 out of range!\n"); 632 return -EINVAL; 633 } 634 635 return 0; 636} 637#else 638static int __ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr) 639{ 640 return 0; 641} 642#endif 643 644int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, 645 unsigned long addr) 646{ 647 unsigned long ip = rec->ip; 648 ppc_inst_t old, new; 649 650 /* 651 * If the calling address is more that 24 bits away, 652 * then we had to use a trampoline to make the call. 653 * Otherwise just update the call site. 654 */ 655 if (test_24bit_addr(ip, addr) && test_24bit_addr(ip, old_addr)) { 656 /* within range */ 657 old = ftrace_call_replace(ip, old_addr, 1); 658 new = ftrace_call_replace(ip, addr, 1); 659 return ftrace_modify_code(ip, old, new); 660 } else if (core_kernel_text(ip)) { 661 /* 662 * We always patch out of range locations to go to the regs 663 * variant, so there is nothing to do here 664 */ 665 return 0; 666 } else if (!IS_ENABLED(CONFIG_MODULES)) { 667 /* We should not get here without modules */ 668 return -EINVAL; 669 } 670 671 /* 672 * Out of range jumps are called from modules. 673 */ 674 if (!rec->arch.mod) { 675 pr_err("No module loaded\n"); 676 return -EINVAL; 677 } 678 679 return __ftrace_modify_call(rec, old_addr, addr); 680} 681#endif 682 683int ftrace_update_ftrace_func(ftrace_func_t func) 684{ 685 unsigned long ip = (unsigned long)(&ftrace_call); 686 ppc_inst_t old, new; 687 int ret; 688 689 old = ppc_inst_read((u32 *)&ftrace_call); 690 new = ftrace_call_replace(ip, (unsigned long)func, 1); 691 ret = ftrace_modify_code(ip, old, new); 692 693 /* Also update the regs callback function */ 694 if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !ret) { 695 ip = (unsigned long)(&ftrace_regs_call); 696 old = ppc_inst_read((u32 *)&ftrace_regs_call); 697 new = ftrace_call_replace(ip, (unsigned long)func, 1); 698 ret = ftrace_modify_code(ip, old, new); 699 } 700 701 return ret; 702} 703 704/* 705 * Use the default ftrace_modify_all_code, but without 706 * stop_machine(). 707 */ 708void arch_ftrace_update_code(int command) 709{ 710 ftrace_modify_all_code(command); 711} 712 713#ifdef CONFIG_PPC64 714#define PACATOC offsetof(struct paca_struct, kernel_toc) 715 716extern unsigned int ftrace_tramp_text[], ftrace_tramp_init[]; 717 718void ftrace_free_init_tramp(void) 719{ 720 int i; 721 722 for (i = 0; i < NUM_FTRACE_TRAMPS && ftrace_tramps[i]; i++) 723 if (ftrace_tramps[i] == (unsigned long)ftrace_tramp_init) { 724 ftrace_tramps[i] = 0; 725 return; 726 } 727} 728 729int __init ftrace_dyn_arch_init(void) 730{ 731 int i; 732 unsigned int *tramp[] = { ftrace_tramp_text, ftrace_tramp_init }; 733 u32 stub_insns[] = { 734 PPC_RAW_LD(_R12, _R13, PACATOC), 735 PPC_RAW_ADDIS(_R12, _R12, 0), 736 PPC_RAW_ADDI(_R12, _R12, 0), 737 PPC_RAW_MTCTR(_R12), 738 PPC_RAW_BCTR() 739 }; 740 unsigned long addr; 741 long reladdr; 742 743 if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS)) 744 addr = ppc_global_function_entry((void *)ftrace_regs_caller); 745 else 746 addr = ppc_global_function_entry((void *)ftrace_caller); 747 748 reladdr = addr - kernel_toc_addr(); 749 750 if (reladdr >= SZ_2G || reladdr < -(long)SZ_2G) { 751 pr_err("Address of %ps out of range of kernel_toc.\n", 752 (void *)addr); 753 return -1; 754 } 755 756 for (i = 0; i < 2; i++) { 757 memcpy(tramp[i], stub_insns, sizeof(stub_insns)); 758 tramp[i][1] |= PPC_HA(reladdr); 759 tramp[i][2] |= PPC_LO(reladdr); 760 add_ftrace_tramp((unsigned long)tramp[i]); 761 } 762 763 return 0; 764} 765#endif 766 767#ifdef CONFIG_FUNCTION_GRAPH_TRACER 768 769extern void ftrace_graph_call(void); 770extern void ftrace_graph_stub(void); 771 772static int ftrace_modify_ftrace_graph_caller(bool enable) 773{ 774 unsigned long ip = (unsigned long)(&ftrace_graph_call); 775 unsigned long addr = (unsigned long)(&ftrace_graph_caller); 776 unsigned long stub = (unsigned long)(&ftrace_graph_stub); 777 ppc_inst_t old, new; 778 779 if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_ARGS)) 780 return 0; 781 782 old = ftrace_call_replace(ip, enable ? stub : addr, 0); 783 new = ftrace_call_replace(ip, enable ? addr : stub, 0); 784 785 return ftrace_modify_code(ip, old, new); 786} 787 788int ftrace_enable_ftrace_graph_caller(void) 789{ 790 return ftrace_modify_ftrace_graph_caller(true); 791} 792 793int ftrace_disable_ftrace_graph_caller(void) 794{ 795 return ftrace_modify_ftrace_graph_caller(false); 796} 797 798/* 799 * Hook the return address and push it in the stack of return addrs 800 * in current thread info. Return the address we want to divert to. 801 */ 802static unsigned long 803__prepare_ftrace_return(unsigned long parent, unsigned long ip, unsigned long sp) 804{ 805 unsigned long return_hooker; 806 int bit; 807 808 if (unlikely(ftrace_graph_is_dead())) 809 goto out; 810 811 if (unlikely(atomic_read(¤t->tracing_graph_pause))) 812 goto out; 813 814 bit = ftrace_test_recursion_trylock(ip, parent); 815 if (bit < 0) 816 goto out; 817 818 return_hooker = ppc_function_entry(return_to_handler); 819 820 if (!function_graph_enter(parent, ip, 0, (unsigned long *)sp)) 821 parent = return_hooker; 822 823 ftrace_test_recursion_unlock(bit); 824out: 825 return parent; 826} 827 828#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS 829void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, 830 struct ftrace_ops *op, struct ftrace_regs *fregs) 831{ 832 fregs->regs.link = __prepare_ftrace_return(parent_ip, ip, fregs->regs.gpr[1]); 833} 834#else 835unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip, 836 unsigned long sp) 837{ 838 return __prepare_ftrace_return(parent, ip, sp); 839} 840#endif 841#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 842 843#ifdef CONFIG_PPC64_ELF_ABI_V1 844char *arch_ftrace_match_adjust(char *str, const char *search) 845{ 846 if (str[0] == '.' && search[0] != '.') 847 return str + 1; 848 else 849 return str; 850} 851#endif /* CONFIG_PPC64_ELF_ABI_V1 */ 852