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