1 /* 2 * PowerPC version 3 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 4 * 5 * Derived from "arch/m68k/kernel/ptrace.c" 6 * Copyright (C) 1994 by Hamish Macdonald 7 * Taken from linux/kernel/ptrace.c and modified for M680x0. 8 * linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds 9 * 10 * Modified by Cort Dougan (cort@hq.fsmlabs.com) 11 * and Paul Mackerras (paulus@samba.org). 12 * 13 * This file is subject to the terms and conditions of the GNU General 14 * Public License. See the file README.legal in the main directory of 15 * this archive for more details. 16 */ 17 18 #include <linux/regset.h> 19 #include <linux/tracehook.h> 20 #include <linux/audit.h> 21 #include <linux/context_tracking.h> 22 #include <linux/syscalls.h> 23 24 #include <asm/switch_to.h> 25 #include <asm/asm-prototypes.h> 26 #include <asm/debug.h> 27 28 #define CREATE_TRACE_POINTS 29 #include <trace/events/syscalls.h> 30 31 #include "ptrace-decl.h" 32 33 /* 34 * Called by kernel/ptrace.c when detaching.. 35 * 36 * Make sure single step bits etc are not set. 37 */ 38 void ptrace_disable(struct task_struct *child) 39 { 40 /* make sure the single step bit is not set. */ 41 user_disable_single_step(child); 42 } 43 44 long arch_ptrace(struct task_struct *child, long request, 45 unsigned long addr, unsigned long data) 46 { 47 int ret = -EPERM; 48 void __user *datavp = (void __user *) data; 49 unsigned long __user *datalp = datavp; 50 51 switch (request) { 52 /* read the word at location addr in the USER area. */ 53 case PTRACE_PEEKUSR: { 54 unsigned long index, tmp; 55 56 ret = -EIO; 57 /* convert to index and check */ 58 index = addr / sizeof(long); 59 if ((addr & (sizeof(long) - 1)) || (index > PT_FPSCR) 60 || (child->thread.regs == NULL)) 61 break; 62 63 CHECK_FULL_REGS(child->thread.regs); 64 if (index < PT_FPR0) { 65 ret = ptrace_get_reg(child, (int) index, &tmp); 66 if (ret) 67 break; 68 } else { 69 unsigned int fpidx = index - PT_FPR0; 70 71 flush_fp_to_thread(child); 72 if (fpidx < (PT_FPSCR - PT_FPR0)) 73 memcpy(&tmp, &child->thread.TS_FPR(fpidx), 74 sizeof(long)); 75 else 76 tmp = child->thread.fp_state.fpscr; 77 } 78 ret = put_user(tmp, datalp); 79 break; 80 } 81 82 /* write the word at location addr in the USER area */ 83 case PTRACE_POKEUSR: { 84 unsigned long index; 85 86 ret = -EIO; 87 /* convert to index and check */ 88 index = addr / sizeof(long); 89 if ((addr & (sizeof(long) - 1)) || (index > PT_FPSCR) 90 || (child->thread.regs == NULL)) 91 break; 92 93 CHECK_FULL_REGS(child->thread.regs); 94 if (index < PT_FPR0) { 95 ret = ptrace_put_reg(child, index, data); 96 } else { 97 unsigned int fpidx = index - PT_FPR0; 98 99 flush_fp_to_thread(child); 100 if (fpidx < (PT_FPSCR - PT_FPR0)) 101 memcpy(&child->thread.TS_FPR(fpidx), &data, 102 sizeof(long)); 103 else 104 child->thread.fp_state.fpscr = data; 105 ret = 0; 106 } 107 break; 108 } 109 110 case PPC_PTRACE_GETHWDBGINFO: { 111 struct ppc_debug_info dbginfo; 112 113 ppc_gethwdinfo(&dbginfo); 114 115 if (copy_to_user(datavp, &dbginfo, 116 sizeof(struct ppc_debug_info))) 117 return -EFAULT; 118 return 0; 119 } 120 121 case PPC_PTRACE_SETHWDEBUG: { 122 struct ppc_hw_breakpoint bp_info; 123 124 if (copy_from_user(&bp_info, datavp, 125 sizeof(struct ppc_hw_breakpoint))) 126 return -EFAULT; 127 return ppc_set_hwdebug(child, &bp_info); 128 } 129 130 case PPC_PTRACE_DELHWDEBUG: { 131 ret = ppc_del_hwdebug(child, data); 132 break; 133 } 134 135 case PTRACE_GET_DEBUGREG: 136 ret = ptrace_get_debugreg(child, addr, datalp); 137 break; 138 139 case PTRACE_SET_DEBUGREG: 140 ret = ptrace_set_debugreg(child, addr, data); 141 break; 142 143 #ifdef CONFIG_PPC64 144 case PTRACE_GETREGS64: 145 #endif 146 case PTRACE_GETREGS: /* Get all pt_regs from the child. */ 147 return copy_regset_to_user(child, &user_ppc_native_view, 148 REGSET_GPR, 149 0, sizeof(struct user_pt_regs), 150 datavp); 151 152 #ifdef CONFIG_PPC64 153 case PTRACE_SETREGS64: 154 #endif 155 case PTRACE_SETREGS: /* Set all gp regs in the child. */ 156 return copy_regset_from_user(child, &user_ppc_native_view, 157 REGSET_GPR, 158 0, sizeof(struct user_pt_regs), 159 datavp); 160 161 case PTRACE_GETFPREGS: /* Get the child FPU state (FPR0...31 + FPSCR) */ 162 return copy_regset_to_user(child, &user_ppc_native_view, 163 REGSET_FPR, 164 0, sizeof(elf_fpregset_t), 165 datavp); 166 167 case PTRACE_SETFPREGS: /* Set the child FPU state (FPR0...31 + FPSCR) */ 168 return copy_regset_from_user(child, &user_ppc_native_view, 169 REGSET_FPR, 170 0, sizeof(elf_fpregset_t), 171 datavp); 172 173 #ifdef CONFIG_ALTIVEC 174 case PTRACE_GETVRREGS: 175 return copy_regset_to_user(child, &user_ppc_native_view, 176 REGSET_VMX, 177 0, (33 * sizeof(vector128) + 178 sizeof(u32)), 179 datavp); 180 181 case PTRACE_SETVRREGS: 182 return copy_regset_from_user(child, &user_ppc_native_view, 183 REGSET_VMX, 184 0, (33 * sizeof(vector128) + 185 sizeof(u32)), 186 datavp); 187 #endif 188 #ifdef CONFIG_VSX 189 case PTRACE_GETVSRREGS: 190 return copy_regset_to_user(child, &user_ppc_native_view, 191 REGSET_VSX, 192 0, 32 * sizeof(double), 193 datavp); 194 195 case PTRACE_SETVSRREGS: 196 return copy_regset_from_user(child, &user_ppc_native_view, 197 REGSET_VSX, 198 0, 32 * sizeof(double), 199 datavp); 200 #endif 201 #ifdef CONFIG_SPE 202 case PTRACE_GETEVRREGS: 203 /* Get the child spe register state. */ 204 return copy_regset_to_user(child, &user_ppc_native_view, 205 REGSET_SPE, 0, 35 * sizeof(u32), 206 datavp); 207 208 case PTRACE_SETEVRREGS: 209 /* Set the child spe register state. */ 210 return copy_regset_from_user(child, &user_ppc_native_view, 211 REGSET_SPE, 0, 35 * sizeof(u32), 212 datavp); 213 #endif 214 215 default: 216 ret = ptrace_request(child, request, addr, data); 217 break; 218 } 219 return ret; 220 } 221 222 #ifdef CONFIG_SECCOMP 223 static int do_seccomp(struct pt_regs *regs) 224 { 225 if (!test_thread_flag(TIF_SECCOMP)) 226 return 0; 227 228 /* 229 * The ABI we present to seccomp tracers is that r3 contains 230 * the syscall return value and orig_gpr3 contains the first 231 * syscall parameter. This is different to the ptrace ABI where 232 * both r3 and orig_gpr3 contain the first syscall parameter. 233 */ 234 regs->gpr[3] = -ENOSYS; 235 236 /* 237 * We use the __ version here because we have already checked 238 * TIF_SECCOMP. If this fails, there is nothing left to do, we 239 * have already loaded -ENOSYS into r3, or seccomp has put 240 * something else in r3 (via SECCOMP_RET_ERRNO/TRACE). 241 */ 242 if (__secure_computing(NULL)) 243 return -1; 244 245 /* 246 * The syscall was allowed by seccomp, restore the register 247 * state to what audit expects. 248 * Note that we use orig_gpr3, which means a seccomp tracer can 249 * modify the first syscall parameter (in orig_gpr3) and also 250 * allow the syscall to proceed. 251 */ 252 regs->gpr[3] = regs->orig_gpr3; 253 254 return 0; 255 } 256 #else 257 static inline int do_seccomp(struct pt_regs *regs) { return 0; } 258 #endif /* CONFIG_SECCOMP */ 259 260 /** 261 * do_syscall_trace_enter() - Do syscall tracing on kernel entry. 262 * @regs: the pt_regs of the task to trace (current) 263 * 264 * Performs various types of tracing on syscall entry. This includes seccomp, 265 * ptrace, syscall tracepoints and audit. 266 * 267 * The pt_regs are potentially visible to userspace via ptrace, so their 268 * contents is ABI. 269 * 270 * One or more of the tracers may modify the contents of pt_regs, in particular 271 * to modify arguments or even the syscall number itself. 272 * 273 * It's also possible that a tracer can choose to reject the system call. In 274 * that case this function will return an illegal syscall number, and will put 275 * an appropriate return value in regs->r3. 276 * 277 * Return: the (possibly changed) syscall number. 278 */ 279 long do_syscall_trace_enter(struct pt_regs *regs) 280 { 281 u32 flags; 282 283 user_exit(); 284 285 flags = READ_ONCE(current_thread_info()->flags) & 286 (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE); 287 288 if (flags) { 289 int rc = tracehook_report_syscall_entry(regs); 290 291 if (unlikely(flags & _TIF_SYSCALL_EMU)) { 292 /* 293 * A nonzero return code from 294 * tracehook_report_syscall_entry() tells us to prevent 295 * the syscall execution, but we are not going to 296 * execute it anyway. 297 * 298 * Returning -1 will skip the syscall execution. We want 299 * to avoid clobbering any registers, so we don't goto 300 * the skip label below. 301 */ 302 return -1; 303 } 304 305 if (rc) { 306 /* 307 * The tracer decided to abort the syscall. Note that 308 * the tracer may also just change regs->gpr[0] to an 309 * invalid syscall number, that is handled below on the 310 * exit path. 311 */ 312 goto skip; 313 } 314 } 315 316 /* Run seccomp after ptrace; allow it to set gpr[3]. */ 317 if (do_seccomp(regs)) 318 return -1; 319 320 /* Avoid trace and audit when syscall is invalid. */ 321 if (regs->gpr[0] >= NR_syscalls) 322 goto skip; 323 324 if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT))) 325 trace_sys_enter(regs, regs->gpr[0]); 326 327 if (!is_32bit_task()) 328 audit_syscall_entry(regs->gpr[0], regs->gpr[3], regs->gpr[4], 329 regs->gpr[5], regs->gpr[6]); 330 else 331 audit_syscall_entry(regs->gpr[0], 332 regs->gpr[3] & 0xffffffff, 333 regs->gpr[4] & 0xffffffff, 334 regs->gpr[5] & 0xffffffff, 335 regs->gpr[6] & 0xffffffff); 336 337 /* Return the possibly modified but valid syscall number */ 338 return regs->gpr[0]; 339 340 skip: 341 /* 342 * If we are aborting explicitly, or if the syscall number is 343 * now invalid, set the return value to -ENOSYS. 344 */ 345 regs->gpr[3] = -ENOSYS; 346 return -1; 347 } 348 349 void do_syscall_trace_leave(struct pt_regs *regs) 350 { 351 int step; 352 353 audit_syscall_exit(regs); 354 355 if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT))) 356 trace_sys_exit(regs, regs->result); 357 358 step = test_thread_flag(TIF_SINGLESTEP); 359 if (step || test_thread_flag(TIF_SYSCALL_TRACE)) 360 tracehook_report_syscall_exit(regs, step); 361 362 user_enter(); 363 } 364 365 void __init pt_regs_check(void); 366 367 /* 368 * Dummy function, its purpose is to break the build if struct pt_regs and 369 * struct user_pt_regs don't match. 370 */ 371 void __init pt_regs_check(void) 372 { 373 BUILD_BUG_ON(offsetof(struct pt_regs, gpr) != 374 offsetof(struct user_pt_regs, gpr)); 375 BUILD_BUG_ON(offsetof(struct pt_regs, nip) != 376 offsetof(struct user_pt_regs, nip)); 377 BUILD_BUG_ON(offsetof(struct pt_regs, msr) != 378 offsetof(struct user_pt_regs, msr)); 379 BUILD_BUG_ON(offsetof(struct pt_regs, msr) != 380 offsetof(struct user_pt_regs, msr)); 381 BUILD_BUG_ON(offsetof(struct pt_regs, orig_gpr3) != 382 offsetof(struct user_pt_regs, orig_gpr3)); 383 BUILD_BUG_ON(offsetof(struct pt_regs, ctr) != 384 offsetof(struct user_pt_regs, ctr)); 385 BUILD_BUG_ON(offsetof(struct pt_regs, link) != 386 offsetof(struct user_pt_regs, link)); 387 BUILD_BUG_ON(offsetof(struct pt_regs, xer) != 388 offsetof(struct user_pt_regs, xer)); 389 BUILD_BUG_ON(offsetof(struct pt_regs, ccr) != 390 offsetof(struct user_pt_regs, ccr)); 391 #ifdef __powerpc64__ 392 BUILD_BUG_ON(offsetof(struct pt_regs, softe) != 393 offsetof(struct user_pt_regs, softe)); 394 #else 395 BUILD_BUG_ON(offsetof(struct pt_regs, mq) != 396 offsetof(struct user_pt_regs, mq)); 397 #endif 398 BUILD_BUG_ON(offsetof(struct pt_regs, trap) != 399 offsetof(struct user_pt_regs, trap)); 400 BUILD_BUG_ON(offsetof(struct pt_regs, dar) != 401 offsetof(struct user_pt_regs, dar)); 402 BUILD_BUG_ON(offsetof(struct pt_regs, dsisr) != 403 offsetof(struct user_pt_regs, dsisr)); 404 BUILD_BUG_ON(offsetof(struct pt_regs, result) != 405 offsetof(struct user_pt_regs, result)); 406 407 BUILD_BUG_ON(sizeof(struct user_pt_regs) > sizeof(struct pt_regs)); 408 409 // Now check that the pt_regs offsets match the uapi #defines 410 #define CHECK_REG(_pt, _reg) \ 411 BUILD_BUG_ON(_pt != (offsetof(struct user_pt_regs, _reg) / \ 412 sizeof(unsigned long))); 413 414 CHECK_REG(PT_R0, gpr[0]); 415 CHECK_REG(PT_R1, gpr[1]); 416 CHECK_REG(PT_R2, gpr[2]); 417 CHECK_REG(PT_R3, gpr[3]); 418 CHECK_REG(PT_R4, gpr[4]); 419 CHECK_REG(PT_R5, gpr[5]); 420 CHECK_REG(PT_R6, gpr[6]); 421 CHECK_REG(PT_R7, gpr[7]); 422 CHECK_REG(PT_R8, gpr[8]); 423 CHECK_REG(PT_R9, gpr[9]); 424 CHECK_REG(PT_R10, gpr[10]); 425 CHECK_REG(PT_R11, gpr[11]); 426 CHECK_REG(PT_R12, gpr[12]); 427 CHECK_REG(PT_R13, gpr[13]); 428 CHECK_REG(PT_R14, gpr[14]); 429 CHECK_REG(PT_R15, gpr[15]); 430 CHECK_REG(PT_R16, gpr[16]); 431 CHECK_REG(PT_R17, gpr[17]); 432 CHECK_REG(PT_R18, gpr[18]); 433 CHECK_REG(PT_R19, gpr[19]); 434 CHECK_REG(PT_R20, gpr[20]); 435 CHECK_REG(PT_R21, gpr[21]); 436 CHECK_REG(PT_R22, gpr[22]); 437 CHECK_REG(PT_R23, gpr[23]); 438 CHECK_REG(PT_R24, gpr[24]); 439 CHECK_REG(PT_R25, gpr[25]); 440 CHECK_REG(PT_R26, gpr[26]); 441 CHECK_REG(PT_R27, gpr[27]); 442 CHECK_REG(PT_R28, gpr[28]); 443 CHECK_REG(PT_R29, gpr[29]); 444 CHECK_REG(PT_R30, gpr[30]); 445 CHECK_REG(PT_R31, gpr[31]); 446 CHECK_REG(PT_NIP, nip); 447 CHECK_REG(PT_MSR, msr); 448 CHECK_REG(PT_ORIG_R3, orig_gpr3); 449 CHECK_REG(PT_CTR, ctr); 450 CHECK_REG(PT_LNK, link); 451 CHECK_REG(PT_XER, xer); 452 CHECK_REG(PT_CCR, ccr); 453 #ifdef CONFIG_PPC64 454 CHECK_REG(PT_SOFTE, softe); 455 #else 456 CHECK_REG(PT_MQ, mq); 457 #endif 458 CHECK_REG(PT_TRAP, trap); 459 CHECK_REG(PT_DAR, dar); 460 CHECK_REG(PT_DSISR, dsisr); 461 CHECK_REG(PT_RESULT, result); 462 #undef CHECK_REG 463 464 BUILD_BUG_ON(PT_REGS_COUNT != sizeof(struct user_pt_regs) / sizeof(unsigned long)); 465 466 /* 467 * PT_DSCR isn't a real reg, but it's important that it doesn't overlap the 468 * real registers. 469 */ 470 BUILD_BUG_ON(PT_DSCR < sizeof(struct user_pt_regs) / sizeof(unsigned long)); 471 } 472