1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Based on arch/arm/kernel/signal.c 4 * 5 * Copyright (C) 1995-2009 Russell King 6 * Copyright (C) 2012 ARM Ltd. 7 * Modified by Will Deacon <will.deacon@arm.com> 8 */ 9 10 #include <linux/compat.h> 11 #include <linux/signal.h> 12 #include <linux/syscalls.h> 13 #include <linux/ratelimit.h> 14 15 #include <asm/esr.h> 16 #include <asm/fpsimd.h> 17 #include <asm/signal32.h> 18 #include <asm/traps.h> 19 #include <linux/uaccess.h> 20 #include <asm/unistd_compat_32.h> 21 #include <asm/vdso.h> 22 23 struct compat_vfp_sigframe { 24 compat_ulong_t magic; 25 compat_ulong_t size; 26 struct compat_user_vfp { 27 compat_u64 fpregs[32]; 28 compat_ulong_t fpscr; 29 } ufp; 30 struct compat_user_vfp_exc { 31 compat_ulong_t fpexc; 32 compat_ulong_t fpinst; 33 compat_ulong_t fpinst2; 34 } ufp_exc; 35 } __attribute__((__aligned__(8))); 36 37 #define VFP_MAGIC 0x56465001 38 #define VFP_STORAGE_SIZE sizeof(struct compat_vfp_sigframe) 39 40 #define FSR_WRITE_SHIFT (11) 41 42 struct compat_aux_sigframe { 43 struct compat_vfp_sigframe vfp; 44 45 /* Something that isn't a valid magic number for any coprocessor. */ 46 unsigned long end_magic; 47 } __attribute__((__aligned__(8))); 48 49 static inline int put_sigset_t(compat_sigset_t __user *uset, sigset_t *set) 50 { 51 compat_sigset_t cset; 52 53 cset.sig[0] = set->sig[0] & 0xffffffffull; 54 cset.sig[1] = set->sig[0] >> 32; 55 56 return copy_to_user(uset, &cset, sizeof(*uset)); 57 } 58 59 static inline int get_sigset_t(sigset_t *set, 60 const compat_sigset_t __user *uset) 61 { 62 compat_sigset_t s32; 63 64 if (copy_from_user(&s32, uset, sizeof(*uset))) 65 return -EFAULT; 66 67 set->sig[0] = s32.sig[0] | (((long)s32.sig[1]) << 32); 68 return 0; 69 } 70 71 /* 72 * VFP save/restore code. 73 */ 74 union __fpsimd_vreg { 75 __uint128_t raw; 76 struct { 77 u64 lo; 78 u64 hi; 79 }; 80 }; 81 82 static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame) 83 { 84 struct user_fpsimd_state const *fpsimd = 85 ¤t->thread.uw.fpsimd_state; 86 compat_ulong_t magic = VFP_MAGIC; 87 compat_ulong_t size = VFP_STORAGE_SIZE; 88 compat_ulong_t fpscr, fpexc; 89 int i, err = 0; 90 91 /* 92 * Save the hardware registers to the fpsimd_state structure. 93 * Note that this also saves V16-31, which aren't visible 94 * in AArch32. 95 */ 96 fpsimd_save_and_flush_current_state(); 97 98 /* Place structure header on the stack */ 99 __put_user_error(magic, &frame->magic, err); 100 __put_user_error(size, &frame->size, err); 101 102 /* 103 * Now copy the FP registers. Since the registers are packed, 104 * we can copy the prefix we want (V0-V15) as it is. 105 */ 106 for (i = 0; i < ARRAY_SIZE(frame->ufp.fpregs); i += 2) { 107 union __fpsimd_vreg vreg = { 108 .raw = fpsimd->vregs[i >> 1], 109 }; 110 111 __put_user_error(vreg.lo, &frame->ufp.fpregs[i], err); 112 __put_user_error(vreg.hi, &frame->ufp.fpregs[i + 1], err); 113 } 114 115 /* Create an AArch32 fpscr from the fpsr and the fpcr. */ 116 fpscr = (fpsimd->fpsr & VFP_FPSCR_STAT_MASK) | 117 (fpsimd->fpcr & VFP_FPSCR_CTRL_MASK); 118 __put_user_error(fpscr, &frame->ufp.fpscr, err); 119 120 /* 121 * The exception register aren't available so we fake up a 122 * basic FPEXC and zero everything else. 123 */ 124 fpexc = (1 << 30); 125 __put_user_error(fpexc, &frame->ufp_exc.fpexc, err); 126 __put_user_error(0, &frame->ufp_exc.fpinst, err); 127 __put_user_error(0, &frame->ufp_exc.fpinst2, err); 128 129 return err ? -EFAULT : 0; 130 } 131 132 static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame) 133 { 134 struct user_fpsimd_state fpsimd; 135 compat_ulong_t magic = VFP_MAGIC; 136 compat_ulong_t size = VFP_STORAGE_SIZE; 137 compat_ulong_t fpscr; 138 int i, err = 0; 139 140 __get_user_error(magic, &frame->magic, err); 141 __get_user_error(size, &frame->size, err); 142 143 if (err) 144 return -EFAULT; 145 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE) 146 return -EINVAL; 147 148 /* Copy the FP registers into the start of the fpsimd_state. */ 149 for (i = 0; i < ARRAY_SIZE(frame->ufp.fpregs); i += 2) { 150 union __fpsimd_vreg vreg; 151 152 __get_user_error(vreg.lo, &frame->ufp.fpregs[i], err); 153 __get_user_error(vreg.hi, &frame->ufp.fpregs[i + 1], err); 154 fpsimd.vregs[i >> 1] = vreg.raw; 155 } 156 157 /* Extract the fpsr and the fpcr from the fpscr */ 158 __get_user_error(fpscr, &frame->ufp.fpscr, err); 159 fpsimd.fpsr = fpscr & VFP_FPSCR_STAT_MASK; 160 fpsimd.fpcr = fpscr & VFP_FPSCR_CTRL_MASK; 161 162 if (err) 163 return -EFAULT; 164 165 /* 166 * We don't need to touch the exception register, so 167 * reload the hardware state. 168 */ 169 fpsimd_save_and_flush_current_state(); 170 current->thread.uw.fpsimd_state = fpsimd; 171 172 return 0; 173 } 174 175 static int compat_restore_sigframe(struct pt_regs *regs, 176 struct compat_sigframe __user *sf) 177 { 178 int err; 179 sigset_t set; 180 struct compat_aux_sigframe __user *aux; 181 unsigned long psr; 182 183 err = get_sigset_t(&set, &sf->uc.uc_sigmask); 184 if (err == 0) 185 set_current_blocked(&set); 186 187 __get_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err); 188 __get_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err); 189 __get_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err); 190 __get_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err); 191 __get_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err); 192 __get_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err); 193 __get_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err); 194 __get_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err); 195 __get_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err); 196 __get_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err); 197 __get_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err); 198 __get_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err); 199 __get_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err); 200 __get_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err); 201 __get_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err); 202 __get_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err); 203 __get_user_error(psr, &sf->uc.uc_mcontext.arm_cpsr, err); 204 205 regs->pstate = compat_psr_to_pstate(psr); 206 207 /* 208 * Avoid compat_sys_sigreturn() restarting. 209 */ 210 forget_syscall(regs); 211 212 err |= !valid_user_regs(®s->user_regs, current); 213 214 aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace; 215 if (err == 0 && system_supports_fpsimd()) 216 err |= compat_restore_vfp_context(&aux->vfp); 217 218 return err; 219 } 220 221 COMPAT_SYSCALL_DEFINE0(sigreturn) 222 { 223 struct pt_regs *regs = current_pt_regs(); 224 struct compat_sigframe __user *frame; 225 226 /* Always make any pending restarted system calls return -EINTR */ 227 current->restart_block.fn = do_no_restart_syscall; 228 229 /* 230 * Since we stacked the signal on a 64-bit boundary, 231 * then 'sp' should be word aligned here. If it's 232 * not, then the user is trying to mess with us. 233 */ 234 if (regs->compat_sp & 7) 235 goto badframe; 236 237 frame = (struct compat_sigframe __user *)regs->compat_sp; 238 239 if (!access_ok(frame, sizeof (*frame))) 240 goto badframe; 241 242 if (compat_restore_sigframe(regs, frame)) 243 goto badframe; 244 245 return regs->regs[0]; 246 247 badframe: 248 arm64_notify_segfault(regs->compat_sp); 249 return 0; 250 } 251 252 COMPAT_SYSCALL_DEFINE0(rt_sigreturn) 253 { 254 struct pt_regs *regs = current_pt_regs(); 255 struct compat_rt_sigframe __user *frame; 256 257 /* Always make any pending restarted system calls return -EINTR */ 258 current->restart_block.fn = do_no_restart_syscall; 259 260 /* 261 * Since we stacked the signal on a 64-bit boundary, 262 * then 'sp' should be word aligned here. If it's 263 * not, then the user is trying to mess with us. 264 */ 265 if (regs->compat_sp & 7) 266 goto badframe; 267 268 frame = (struct compat_rt_sigframe __user *)regs->compat_sp; 269 270 if (!access_ok(frame, sizeof (*frame))) 271 goto badframe; 272 273 if (compat_restore_sigframe(regs, &frame->sig)) 274 goto badframe; 275 276 if (compat_restore_altstack(&frame->sig.uc.uc_stack)) 277 goto badframe; 278 279 return regs->regs[0]; 280 281 badframe: 282 arm64_notify_segfault(regs->compat_sp); 283 return 0; 284 } 285 286 static void __user *compat_get_sigframe(struct ksignal *ksig, 287 struct pt_regs *regs, 288 int framesize) 289 { 290 compat_ulong_t sp = sigsp(regs->compat_sp, ksig); 291 void __user *frame; 292 293 /* 294 * ATPCS B01 mandates 8-byte alignment 295 */ 296 frame = compat_ptr((compat_uptr_t)((sp - framesize) & ~7)); 297 298 /* 299 * Check that we can actually write to the signal frame. 300 */ 301 if (!access_ok(frame, framesize)) 302 frame = NULL; 303 304 return frame; 305 } 306 307 static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka, 308 compat_ulong_t __user *rc, void __user *frame, 309 int usig) 310 { 311 compat_ulong_t handler = ptr_to_compat(ka->sa.sa_handler); 312 compat_ulong_t retcode; 313 compat_ulong_t spsr = regs->pstate & ~(PSR_f | PSR_AA32_E_BIT); 314 int thumb; 315 316 /* Check if the handler is written for ARM or Thumb */ 317 thumb = handler & 1; 318 319 if (thumb) 320 spsr |= PSR_AA32_T_BIT; 321 else 322 spsr &= ~PSR_AA32_T_BIT; 323 324 /* The IT state must be cleared for both ARM and Thumb-2 */ 325 spsr &= ~PSR_AA32_IT_MASK; 326 327 if (ka->sa.sa_flags & SA_RESTORER) { 328 retcode = ptr_to_compat(ka->sa.sa_restorer); 329 } else { 330 /* Set up sigreturn pointer */ 331 unsigned int idx = thumb << 1; 332 333 if (ka->sa.sa_flags & SA_SIGINFO) 334 idx += 3; 335 336 retcode = (unsigned long)current->mm->context.sigpage + 337 (idx << 2) + thumb; 338 } 339 340 regs->regs[0] = usig; 341 regs->compat_sp = ptr_to_compat(frame); 342 regs->compat_lr = retcode; 343 regs->pc = handler; 344 regs->pstate = spsr; 345 } 346 347 static int compat_setup_sigframe(struct compat_sigframe __user *sf, 348 struct pt_regs *regs, sigset_t *set) 349 { 350 struct compat_aux_sigframe __user *aux; 351 unsigned long psr = pstate_to_compat_psr(regs->pstate); 352 int err = 0; 353 354 __put_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err); 355 __put_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err); 356 __put_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err); 357 __put_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err); 358 __put_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err); 359 __put_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err); 360 __put_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err); 361 __put_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err); 362 __put_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err); 363 __put_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err); 364 __put_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err); 365 __put_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err); 366 __put_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err); 367 __put_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err); 368 __put_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err); 369 __put_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err); 370 __put_user_error(psr, &sf->uc.uc_mcontext.arm_cpsr, err); 371 372 __put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.trap_no, err); 373 /* set the compat FSR WnR */ 374 __put_user_error(!!(current->thread.fault_code & ESR_ELx_WNR) << 375 FSR_WRITE_SHIFT, &sf->uc.uc_mcontext.error_code, err); 376 __put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err); 377 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err); 378 379 err |= put_sigset_t(&sf->uc.uc_sigmask, set); 380 381 aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace; 382 383 if (err == 0 && system_supports_fpsimd()) 384 err |= compat_preserve_vfp_context(&aux->vfp); 385 __put_user_error(0, &aux->end_magic, err); 386 387 return err; 388 } 389 390 /* 391 * 32-bit signal handling routines called from signal.c 392 */ 393 int compat_setup_rt_frame(int usig, struct ksignal *ksig, 394 sigset_t *set, struct pt_regs *regs) 395 { 396 struct compat_rt_sigframe __user *frame; 397 int err = 0; 398 399 frame = compat_get_sigframe(ksig, regs, sizeof(*frame)); 400 401 if (!frame) 402 return 1; 403 404 err |= copy_siginfo_to_user32(&frame->info, &ksig->info); 405 406 __put_user_error(0, &frame->sig.uc.uc_flags, err); 407 __put_user_error(0, &frame->sig.uc.uc_link, err); 408 409 err |= __compat_save_altstack(&frame->sig.uc.uc_stack, regs->compat_sp); 410 411 err |= compat_setup_sigframe(&frame->sig, regs, set); 412 413 if (err == 0) { 414 compat_setup_return(regs, &ksig->ka, frame->sig.retcode, frame, usig); 415 regs->regs[1] = (compat_ulong_t)(unsigned long)&frame->info; 416 regs->regs[2] = (compat_ulong_t)(unsigned long)&frame->sig.uc; 417 } 418 419 return err; 420 } 421 422 int compat_setup_frame(int usig, struct ksignal *ksig, sigset_t *set, 423 struct pt_regs *regs) 424 { 425 struct compat_sigframe __user *frame; 426 int err = 0; 427 428 frame = compat_get_sigframe(ksig, regs, sizeof(*frame)); 429 430 if (!frame) 431 return 1; 432 433 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err); 434 435 err |= compat_setup_sigframe(frame, regs, set); 436 if (err == 0) 437 compat_setup_return(regs, &ksig->ka, frame->retcode, frame, usig); 438 439 return err; 440 } 441 442 void compat_setup_restart_syscall(struct pt_regs *regs) 443 { 444 regs->regs[7] = __NR_compat32_restart_syscall; 445 } 446 447 /* 448 * Compile-time assertions for siginfo_t offsets. Check NSIG* as well, as 449 * changes likely come with new fields that should be added below. 450 */ 451 static_assert(NSIGILL == 11); 452 static_assert(NSIGFPE == 15); 453 static_assert(NSIGSEGV == 10); 454 static_assert(NSIGBUS == 5); 455 static_assert(NSIGTRAP == 6); 456 static_assert(NSIGCHLD == 6); 457 static_assert(NSIGSYS == 2); 458 static_assert(sizeof(compat_siginfo_t) == 128); 459 static_assert(__alignof__(compat_siginfo_t) == 4); 460 static_assert(offsetof(compat_siginfo_t, si_signo) == 0x00); 461 static_assert(offsetof(compat_siginfo_t, si_errno) == 0x04); 462 static_assert(offsetof(compat_siginfo_t, si_code) == 0x08); 463 static_assert(offsetof(compat_siginfo_t, si_pid) == 0x0c); 464 static_assert(offsetof(compat_siginfo_t, si_uid) == 0x10); 465 static_assert(offsetof(compat_siginfo_t, si_tid) == 0x0c); 466 static_assert(offsetof(compat_siginfo_t, si_overrun) == 0x10); 467 static_assert(offsetof(compat_siginfo_t, si_status) == 0x14); 468 static_assert(offsetof(compat_siginfo_t, si_utime) == 0x18); 469 static_assert(offsetof(compat_siginfo_t, si_stime) == 0x1c); 470 static_assert(offsetof(compat_siginfo_t, si_value) == 0x14); 471 static_assert(offsetof(compat_siginfo_t, si_int) == 0x14); 472 static_assert(offsetof(compat_siginfo_t, si_ptr) == 0x14); 473 static_assert(offsetof(compat_siginfo_t, si_addr) == 0x0c); 474 static_assert(offsetof(compat_siginfo_t, si_addr_lsb) == 0x10); 475 static_assert(offsetof(compat_siginfo_t, si_lower) == 0x14); 476 static_assert(offsetof(compat_siginfo_t, si_upper) == 0x18); 477 static_assert(offsetof(compat_siginfo_t, si_pkey) == 0x14); 478 static_assert(offsetof(compat_siginfo_t, si_perf_data) == 0x10); 479 static_assert(offsetof(compat_siginfo_t, si_perf_type) == 0x14); 480 static_assert(offsetof(compat_siginfo_t, si_perf_flags) == 0x18); 481 static_assert(offsetof(compat_siginfo_t, si_band) == 0x0c); 482 static_assert(offsetof(compat_siginfo_t, si_fd) == 0x10); 483 static_assert(offsetof(compat_siginfo_t, si_call_addr) == 0x0c); 484 static_assert(offsetof(compat_siginfo_t, si_syscall) == 0x10); 485 static_assert(offsetof(compat_siginfo_t, si_arch) == 0x14); 486