| 1 | /* |
| 2 | * arch/sparc64/kernel/signal.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 5 | * Copyright (C) 1995, 2008 David S. Miller (davem@davemloft.net) |
| 6 | * Copyright (C) 1996 Miguel de Icaza (miguel@nuclecu.unam.mx) |
| 7 | * Copyright (C) 1997 Eddie C. Dost (ecd@skynet.be) |
| 8 | * Copyright (C) 1997,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz) |
| 9 | */ |
| 10 | |
| 11 | #ifdef CONFIG_COMPAT |
| 12 | #include <linux/compat.h> /* for compat_old_sigset_t */ |
| 13 | #endif |
| 14 | #include <linux/sched.h> |
| 15 | #include <linux/kernel.h> |
| 16 | #include <linux/signal.h> |
| 17 | #include <linux/errno.h> |
| 18 | #include <linux/wait.h> |
| 19 | #include <linux/ptrace.h> |
| 20 | #include <linux/tracehook.h> |
| 21 | #include <linux/unistd.h> |
| 22 | #include <linux/mm.h> |
| 23 | #include <linux/tty.h> |
| 24 | #include <linux/binfmts.h> |
| 25 | #include <linux/bitops.h> |
| 26 | #include <linux/context_tracking.h> |
| 27 | |
| 28 | #include <asm/uaccess.h> |
| 29 | #include <asm/ptrace.h> |
| 30 | #include <asm/pgtable.h> |
| 31 | #include <asm/fpumacro.h> |
| 32 | #include <asm/uctx.h> |
| 33 | #include <asm/siginfo.h> |
| 34 | #include <asm/visasm.h> |
| 35 | #include <asm/switch_to.h> |
| 36 | #include <asm/cacheflush.h> |
| 37 | |
| 38 | #include "sigutil.h" |
| 39 | #include "systbls.h" |
| 40 | #include "kernel.h" |
| 41 | #include "entry.h" |
| 42 | |
| 43 | /* {set, get}context() needed for 64-bit SparcLinux userland. */ |
| 44 | asmlinkage void sparc64_set_context(struct pt_regs *regs) |
| 45 | { |
| 46 | struct ucontext __user *ucp = (struct ucontext __user *) |
| 47 | regs->u_regs[UREG_I0]; |
| 48 | enum ctx_state prev_state = exception_enter(); |
| 49 | mc_gregset_t __user *grp; |
| 50 | unsigned long pc, npc, tstate; |
| 51 | unsigned long fp, i7; |
| 52 | unsigned char fenab; |
| 53 | int err; |
| 54 | |
| 55 | flush_user_windows(); |
| 56 | if (get_thread_wsaved() || |
| 57 | (((unsigned long)ucp) & (sizeof(unsigned long)-1)) || |
| 58 | (!__access_ok(ucp, sizeof(*ucp)))) |
| 59 | goto do_sigsegv; |
| 60 | grp = &ucp->uc_mcontext.mc_gregs; |
| 61 | err = __get_user(pc, &((*grp)[MC_PC])); |
| 62 | err |= __get_user(npc, &((*grp)[MC_NPC])); |
| 63 | if (err || ((pc | npc) & 3)) |
| 64 | goto do_sigsegv; |
| 65 | if (regs->u_regs[UREG_I1]) { |
| 66 | sigset_t set; |
| 67 | |
| 68 | if (_NSIG_WORDS == 1) { |
| 69 | if (__get_user(set.sig[0], &ucp->uc_sigmask.sig[0])) |
| 70 | goto do_sigsegv; |
| 71 | } else { |
| 72 | if (__copy_from_user(&set, &ucp->uc_sigmask, sizeof(sigset_t))) |
| 73 | goto do_sigsegv; |
| 74 | } |
| 75 | set_current_blocked(&set); |
| 76 | } |
| 77 | if (test_thread_flag(TIF_32BIT)) { |
| 78 | pc &= 0xffffffff; |
| 79 | npc &= 0xffffffff; |
| 80 | } |
| 81 | regs->tpc = pc; |
| 82 | regs->tnpc = npc; |
| 83 | err |= __get_user(regs->y, &((*grp)[MC_Y])); |
| 84 | err |= __get_user(tstate, &((*grp)[MC_TSTATE])); |
| 85 | regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC); |
| 86 | regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC)); |
| 87 | err |= __get_user(regs->u_regs[UREG_G1], (&(*grp)[MC_G1])); |
| 88 | err |= __get_user(regs->u_regs[UREG_G2], (&(*grp)[MC_G2])); |
| 89 | err |= __get_user(regs->u_regs[UREG_G3], (&(*grp)[MC_G3])); |
| 90 | err |= __get_user(regs->u_regs[UREG_G4], (&(*grp)[MC_G4])); |
| 91 | err |= __get_user(regs->u_regs[UREG_G5], (&(*grp)[MC_G5])); |
| 92 | err |= __get_user(regs->u_regs[UREG_G6], (&(*grp)[MC_G6])); |
| 93 | |
| 94 | /* Skip %g7 as that's the thread register in userspace. */ |
| 95 | |
| 96 | err |= __get_user(regs->u_regs[UREG_I0], (&(*grp)[MC_O0])); |
| 97 | err |= __get_user(regs->u_regs[UREG_I1], (&(*grp)[MC_O1])); |
| 98 | err |= __get_user(regs->u_regs[UREG_I2], (&(*grp)[MC_O2])); |
| 99 | err |= __get_user(regs->u_regs[UREG_I3], (&(*grp)[MC_O3])); |
| 100 | err |= __get_user(regs->u_regs[UREG_I4], (&(*grp)[MC_O4])); |
| 101 | err |= __get_user(regs->u_regs[UREG_I5], (&(*grp)[MC_O5])); |
| 102 | err |= __get_user(regs->u_regs[UREG_I6], (&(*grp)[MC_O6])); |
| 103 | err |= __get_user(regs->u_regs[UREG_I7], (&(*grp)[MC_O7])); |
| 104 | |
| 105 | err |= __get_user(fp, &(ucp->uc_mcontext.mc_fp)); |
| 106 | err |= __get_user(i7, &(ucp->uc_mcontext.mc_i7)); |
| 107 | err |= __put_user(fp, |
| 108 | (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6]))); |
| 109 | err |= __put_user(i7, |
| 110 | (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7]))); |
| 111 | |
| 112 | err |= __get_user(fenab, &(ucp->uc_mcontext.mc_fpregs.mcfpu_enab)); |
| 113 | if (fenab) { |
| 114 | unsigned long *fpregs = current_thread_info()->fpregs; |
| 115 | unsigned long fprs; |
| 116 | |
| 117 | fprs_write(0); |
| 118 | err |= __get_user(fprs, &(ucp->uc_mcontext.mc_fpregs.mcfpu_fprs)); |
| 119 | if (fprs & FPRS_DL) |
| 120 | err |= copy_from_user(fpregs, |
| 121 | &(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs), |
| 122 | (sizeof(unsigned int) * 32)); |
| 123 | if (fprs & FPRS_DU) |
| 124 | err |= copy_from_user(fpregs+16, |
| 125 | ((unsigned long __user *)&(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs))+16, |
| 126 | (sizeof(unsigned int) * 32)); |
| 127 | err |= __get_user(current_thread_info()->xfsr[0], |
| 128 | &(ucp->uc_mcontext.mc_fpregs.mcfpu_fsr)); |
| 129 | err |= __get_user(current_thread_info()->gsr[0], |
| 130 | &(ucp->uc_mcontext.mc_fpregs.mcfpu_gsr)); |
| 131 | regs->tstate &= ~TSTATE_PEF; |
| 132 | } |
| 133 | if (err) |
| 134 | goto do_sigsegv; |
| 135 | out: |
| 136 | exception_exit(prev_state); |
| 137 | return; |
| 138 | do_sigsegv: |
| 139 | force_sig(SIGSEGV, current); |
| 140 | goto out; |
| 141 | } |
| 142 | |
| 143 | asmlinkage void sparc64_get_context(struct pt_regs *regs) |
| 144 | { |
| 145 | struct ucontext __user *ucp = (struct ucontext __user *) |
| 146 | regs->u_regs[UREG_I0]; |
| 147 | enum ctx_state prev_state = exception_enter(); |
| 148 | mc_gregset_t __user *grp; |
| 149 | mcontext_t __user *mcp; |
| 150 | unsigned long fp, i7; |
| 151 | unsigned char fenab; |
| 152 | int err; |
| 153 | |
| 154 | synchronize_user_stack(); |
| 155 | if (get_thread_wsaved() || clear_user(ucp, sizeof(*ucp))) |
| 156 | goto do_sigsegv; |
| 157 | |
| 158 | #if 1 |
| 159 | fenab = 0; /* IMO get_context is like any other system call, thus modifies FPU state -jj */ |
| 160 | #else |
| 161 | fenab = (current_thread_info()->fpsaved[0] & FPRS_FEF); |
| 162 | #endif |
| 163 | |
| 164 | mcp = &ucp->uc_mcontext; |
| 165 | grp = &mcp->mc_gregs; |
| 166 | |
| 167 | /* Skip over the trap instruction, first. */ |
| 168 | if (test_thread_flag(TIF_32BIT)) { |
| 169 | regs->tpc = (regs->tnpc & 0xffffffff); |
| 170 | regs->tnpc = (regs->tnpc + 4) & 0xffffffff; |
| 171 | } else { |
| 172 | regs->tpc = regs->tnpc; |
| 173 | regs->tnpc += 4; |
| 174 | } |
| 175 | err = 0; |
| 176 | if (_NSIG_WORDS == 1) |
| 177 | err |= __put_user(current->blocked.sig[0], |
| 178 | (unsigned long __user *)&ucp->uc_sigmask); |
| 179 | else |
| 180 | err |= __copy_to_user(&ucp->uc_sigmask, ¤t->blocked, |
| 181 | sizeof(sigset_t)); |
| 182 | |
| 183 | err |= __put_user(regs->tstate, &((*grp)[MC_TSTATE])); |
| 184 | err |= __put_user(regs->tpc, &((*grp)[MC_PC])); |
| 185 | err |= __put_user(regs->tnpc, &((*grp)[MC_NPC])); |
| 186 | err |= __put_user(regs->y, &((*grp)[MC_Y])); |
| 187 | err |= __put_user(regs->u_regs[UREG_G1], &((*grp)[MC_G1])); |
| 188 | err |= __put_user(regs->u_regs[UREG_G2], &((*grp)[MC_G2])); |
| 189 | err |= __put_user(regs->u_regs[UREG_G3], &((*grp)[MC_G3])); |
| 190 | err |= __put_user(regs->u_regs[UREG_G4], &((*grp)[MC_G4])); |
| 191 | err |= __put_user(regs->u_regs[UREG_G5], &((*grp)[MC_G5])); |
| 192 | err |= __put_user(regs->u_regs[UREG_G6], &((*grp)[MC_G6])); |
| 193 | err |= __put_user(regs->u_regs[UREG_G7], &((*grp)[MC_G7])); |
| 194 | err |= __put_user(regs->u_regs[UREG_I0], &((*grp)[MC_O0])); |
| 195 | err |= __put_user(regs->u_regs[UREG_I1], &((*grp)[MC_O1])); |
| 196 | err |= __put_user(regs->u_regs[UREG_I2], &((*grp)[MC_O2])); |
| 197 | err |= __put_user(regs->u_regs[UREG_I3], &((*grp)[MC_O3])); |
| 198 | err |= __put_user(regs->u_regs[UREG_I4], &((*grp)[MC_O4])); |
| 199 | err |= __put_user(regs->u_regs[UREG_I5], &((*grp)[MC_O5])); |
| 200 | err |= __put_user(regs->u_regs[UREG_I6], &((*grp)[MC_O6])); |
| 201 | err |= __put_user(regs->u_regs[UREG_I7], &((*grp)[MC_O7])); |
| 202 | |
| 203 | err |= __get_user(fp, |
| 204 | (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6]))); |
| 205 | err |= __get_user(i7, |
| 206 | (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7]))); |
| 207 | err |= __put_user(fp, &(mcp->mc_fp)); |
| 208 | err |= __put_user(i7, &(mcp->mc_i7)); |
| 209 | |
| 210 | err |= __put_user(fenab, &(mcp->mc_fpregs.mcfpu_enab)); |
| 211 | if (fenab) { |
| 212 | unsigned long *fpregs = current_thread_info()->fpregs; |
| 213 | unsigned long fprs; |
| 214 | |
| 215 | fprs = current_thread_info()->fpsaved[0]; |
| 216 | if (fprs & FPRS_DL) |
| 217 | err |= copy_to_user(&(mcp->mc_fpregs.mcfpu_fregs), fpregs, |
| 218 | (sizeof(unsigned int) * 32)); |
| 219 | if (fprs & FPRS_DU) |
| 220 | err |= copy_to_user( |
| 221 | ((unsigned long __user *)&(mcp->mc_fpregs.mcfpu_fregs))+16, fpregs+16, |
| 222 | (sizeof(unsigned int) * 32)); |
| 223 | err |= __put_user(current_thread_info()->xfsr[0], &(mcp->mc_fpregs.mcfpu_fsr)); |
| 224 | err |= __put_user(current_thread_info()->gsr[0], &(mcp->mc_fpregs.mcfpu_gsr)); |
| 225 | err |= __put_user(fprs, &(mcp->mc_fpregs.mcfpu_fprs)); |
| 226 | } |
| 227 | if (err) |
| 228 | goto do_sigsegv; |
| 229 | out: |
| 230 | exception_exit(prev_state); |
| 231 | return; |
| 232 | do_sigsegv: |
| 233 | force_sig(SIGSEGV, current); |
| 234 | goto out; |
| 235 | } |
| 236 | |
| 237 | struct rt_signal_frame { |
| 238 | struct sparc_stackf ss; |
| 239 | siginfo_t info; |
| 240 | struct pt_regs regs; |
| 241 | __siginfo_fpu_t __user *fpu_save; |
| 242 | stack_t stack; |
| 243 | sigset_t mask; |
| 244 | __siginfo_rwin_t *rwin_save; |
| 245 | }; |
| 246 | |
| 247 | void do_rt_sigreturn(struct pt_regs *regs) |
| 248 | { |
| 249 | struct rt_signal_frame __user *sf; |
| 250 | unsigned long tpc, tnpc, tstate; |
| 251 | __siginfo_fpu_t __user *fpu_save; |
| 252 | __siginfo_rwin_t __user *rwin_save; |
| 253 | sigset_t set; |
| 254 | int err; |
| 255 | |
| 256 | /* Always make any pending restarted system calls return -EINTR */ |
| 257 | current_thread_info()->restart_block.fn = do_no_restart_syscall; |
| 258 | |
| 259 | synchronize_user_stack (); |
| 260 | sf = (struct rt_signal_frame __user *) |
| 261 | (regs->u_regs [UREG_FP] + STACK_BIAS); |
| 262 | |
| 263 | /* 1. Make sure we are not getting garbage from the user */ |
| 264 | if (((unsigned long) sf) & 3) |
| 265 | goto segv; |
| 266 | |
| 267 | err = get_user(tpc, &sf->regs.tpc); |
| 268 | err |= __get_user(tnpc, &sf->regs.tnpc); |
| 269 | if (test_thread_flag(TIF_32BIT)) { |
| 270 | tpc &= 0xffffffff; |
| 271 | tnpc &= 0xffffffff; |
| 272 | } |
| 273 | err |= ((tpc | tnpc) & 3); |
| 274 | |
| 275 | /* 2. Restore the state */ |
| 276 | err |= __get_user(regs->y, &sf->regs.y); |
| 277 | err |= __get_user(tstate, &sf->regs.tstate); |
| 278 | err |= copy_from_user(regs->u_regs, sf->regs.u_regs, sizeof(regs->u_regs)); |
| 279 | |
| 280 | /* User can only change condition codes and %asi in %tstate. */ |
| 281 | regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC); |
| 282 | regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC)); |
| 283 | |
| 284 | err |= __get_user(fpu_save, &sf->fpu_save); |
| 285 | if (!err && fpu_save) |
| 286 | err |= restore_fpu_state(regs, fpu_save); |
| 287 | |
| 288 | err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t)); |
| 289 | err |= restore_altstack(&sf->stack); |
| 290 | if (err) |
| 291 | goto segv; |
| 292 | |
| 293 | err |= __get_user(rwin_save, &sf->rwin_save); |
| 294 | if (!err && rwin_save) { |
| 295 | if (restore_rwin_state(rwin_save)) |
| 296 | goto segv; |
| 297 | } |
| 298 | |
| 299 | regs->tpc = tpc; |
| 300 | regs->tnpc = tnpc; |
| 301 | |
| 302 | /* Prevent syscall restart. */ |
| 303 | pt_regs_clear_syscall(regs); |
| 304 | |
| 305 | set_current_blocked(&set); |
| 306 | return; |
| 307 | segv: |
| 308 | force_sig(SIGSEGV, current); |
| 309 | } |
| 310 | |
| 311 | /* Checks if the fp is valid */ |
| 312 | static int invalid_frame_pointer(void __user *fp) |
| 313 | { |
| 314 | if (((unsigned long) fp) & 15) |
| 315 | return 1; |
| 316 | return 0; |
| 317 | } |
| 318 | |
| 319 | static inline void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize) |
| 320 | { |
| 321 | unsigned long sp = regs->u_regs[UREG_FP] + STACK_BIAS; |
| 322 | |
| 323 | /* |
| 324 | * If we are on the alternate signal stack and would overflow it, don't. |
| 325 | * Return an always-bogus address instead so we will die with SIGSEGV. |
| 326 | */ |
| 327 | if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize))) |
| 328 | return (void __user *) -1L; |
| 329 | |
| 330 | /* This is the X/Open sanctioned signal stack switching. */ |
| 331 | sp = sigsp(sp, ksig) - framesize; |
| 332 | |
| 333 | /* Always align the stack frame. This handles two cases. First, |
| 334 | * sigaltstack need not be mindful of platform specific stack |
| 335 | * alignment. Second, if we took this signal because the stack |
| 336 | * is not aligned properly, we'd like to take the signal cleanly |
| 337 | * and report that. |
| 338 | */ |
| 339 | sp &= ~15UL; |
| 340 | |
| 341 | return (void __user *) sp; |
| 342 | } |
| 343 | |
| 344 | static inline int |
| 345 | setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) |
| 346 | { |
| 347 | struct rt_signal_frame __user *sf; |
| 348 | int wsaved, err, sf_size; |
| 349 | void __user *tail; |
| 350 | |
| 351 | /* 1. Make sure everything is clean */ |
| 352 | synchronize_user_stack(); |
| 353 | save_and_clear_fpu(); |
| 354 | |
| 355 | wsaved = get_thread_wsaved(); |
| 356 | |
| 357 | sf_size = sizeof(struct rt_signal_frame); |
| 358 | if (current_thread_info()->fpsaved[0] & FPRS_FEF) |
| 359 | sf_size += sizeof(__siginfo_fpu_t); |
| 360 | if (wsaved) |
| 361 | sf_size += sizeof(__siginfo_rwin_t); |
| 362 | sf = (struct rt_signal_frame __user *) |
| 363 | get_sigframe(ksig, regs, sf_size); |
| 364 | |
| 365 | if (invalid_frame_pointer (sf)) { |
| 366 | do_exit(SIGILL); /* won't return, actually */ |
| 367 | return -EINVAL; |
| 368 | } |
| 369 | |
| 370 | tail = (sf + 1); |
| 371 | |
| 372 | /* 2. Save the current process state */ |
| 373 | err = copy_to_user(&sf->regs, regs, sizeof (*regs)); |
| 374 | |
| 375 | if (current_thread_info()->fpsaved[0] & FPRS_FEF) { |
| 376 | __siginfo_fpu_t __user *fpu_save = tail; |
| 377 | tail += sizeof(__siginfo_fpu_t); |
| 378 | err |= save_fpu_state(regs, fpu_save); |
| 379 | err |= __put_user((u64)fpu_save, &sf->fpu_save); |
| 380 | } else { |
| 381 | err |= __put_user(0, &sf->fpu_save); |
| 382 | } |
| 383 | if (wsaved) { |
| 384 | __siginfo_rwin_t __user *rwin_save = tail; |
| 385 | tail += sizeof(__siginfo_rwin_t); |
| 386 | err |= save_rwin_state(wsaved, rwin_save); |
| 387 | err |= __put_user((u64)rwin_save, &sf->rwin_save); |
| 388 | set_thread_wsaved(0); |
| 389 | } else { |
| 390 | err |= __put_user(0, &sf->rwin_save); |
| 391 | } |
| 392 | |
| 393 | /* Setup sigaltstack */ |
| 394 | err |= __save_altstack(&sf->stack, regs->u_regs[UREG_FP]); |
| 395 | |
| 396 | err |= copy_to_user(&sf->mask, sigmask_to_save(), sizeof(sigset_t)); |
| 397 | |
| 398 | if (!wsaved) { |
| 399 | err |= copy_in_user((u64 __user *)sf, |
| 400 | (u64 __user *)(regs->u_regs[UREG_FP] + |
| 401 | STACK_BIAS), |
| 402 | sizeof(struct reg_window)); |
| 403 | } else { |
| 404 | struct reg_window *rp; |
| 405 | |
| 406 | rp = ¤t_thread_info()->reg_window[wsaved - 1]; |
| 407 | err |= copy_to_user(sf, rp, sizeof(struct reg_window)); |
| 408 | } |
| 409 | if (ksig->ka.sa.sa_flags & SA_SIGINFO) |
| 410 | err |= copy_siginfo_to_user(&sf->info, &ksig->info); |
| 411 | else { |
| 412 | err |= __put_user(ksig->sig, &sf->info.si_signo); |
| 413 | err |= __put_user(SI_NOINFO, &sf->info.si_code); |
| 414 | } |
| 415 | if (err) |
| 416 | return err; |
| 417 | |
| 418 | /* 3. signal handler back-trampoline and parameters */ |
| 419 | regs->u_regs[UREG_FP] = ((unsigned long) sf) - STACK_BIAS; |
| 420 | regs->u_regs[UREG_I0] = ksig->sig; |
| 421 | regs->u_regs[UREG_I1] = (unsigned long) &sf->info; |
| 422 | |
| 423 | /* The sigcontext is passed in this way because of how it |
| 424 | * is defined in GLIBC's /usr/include/bits/sigcontext.h |
| 425 | * for sparc64. It includes the 128 bytes of siginfo_t. |
| 426 | */ |
| 427 | regs->u_regs[UREG_I2] = (unsigned long) &sf->info; |
| 428 | |
| 429 | /* 5. signal handler */ |
| 430 | regs->tpc = (unsigned long) ksig->ka.sa.sa_handler; |
| 431 | regs->tnpc = (regs->tpc + 4); |
| 432 | if (test_thread_flag(TIF_32BIT)) { |
| 433 | regs->tpc &= 0xffffffff; |
| 434 | regs->tnpc &= 0xffffffff; |
| 435 | } |
| 436 | /* 4. return to kernel instructions */ |
| 437 | regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer; |
| 438 | return 0; |
| 439 | } |
| 440 | |
| 441 | static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs, |
| 442 | struct sigaction *sa) |
| 443 | { |
| 444 | switch (regs->u_regs[UREG_I0]) { |
| 445 | case ERESTART_RESTARTBLOCK: |
| 446 | case ERESTARTNOHAND: |
| 447 | no_system_call_restart: |
| 448 | regs->u_regs[UREG_I0] = EINTR; |
| 449 | regs->tstate |= (TSTATE_ICARRY|TSTATE_XCARRY); |
| 450 | break; |
| 451 | case ERESTARTSYS: |
| 452 | if (!(sa->sa_flags & SA_RESTART)) |
| 453 | goto no_system_call_restart; |
| 454 | /* fallthrough */ |
| 455 | case ERESTARTNOINTR: |
| 456 | regs->u_regs[UREG_I0] = orig_i0; |
| 457 | regs->tpc -= 4; |
| 458 | regs->tnpc -= 4; |
| 459 | } |
| 460 | } |
| 461 | |
| 462 | /* Note that 'init' is a special process: it doesn't get signals it doesn't |
| 463 | * want to handle. Thus you cannot kill init even with a SIGKILL even by |
| 464 | * mistake. |
| 465 | */ |
| 466 | static void do_signal(struct pt_regs *regs, unsigned long orig_i0) |
| 467 | { |
| 468 | struct ksignal ksig; |
| 469 | int restart_syscall; |
| 470 | bool has_handler; |
| 471 | |
| 472 | /* It's a lot of work and synchronization to add a new ptrace |
| 473 | * register for GDB to save and restore in order to get |
| 474 | * orig_i0 correct for syscall restarts when debugging. |
| 475 | * |
| 476 | * Although it should be the case that most of the global |
| 477 | * registers are volatile across a system call, glibc already |
| 478 | * depends upon that fact that we preserve them. So we can't |
| 479 | * just use any global register to save away the orig_i0 value. |
| 480 | * |
| 481 | * In particular %g2, %g3, %g4, and %g5 are all assumed to be |
| 482 | * preserved across a system call trap by various pieces of |
| 483 | * code in glibc. |
| 484 | * |
| 485 | * %g7 is used as the "thread register". %g6 is not used in |
| 486 | * any fixed manner. %g6 is used as a scratch register and |
| 487 | * a compiler temporary, but it's value is never used across |
| 488 | * a system call. Therefore %g6 is usable for orig_i0 storage. |
| 489 | */ |
| 490 | if (pt_regs_is_syscall(regs) && |
| 491 | (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) |
| 492 | regs->u_regs[UREG_G6] = orig_i0; |
| 493 | |
| 494 | #ifdef CONFIG_COMPAT |
| 495 | if (test_thread_flag(TIF_32BIT)) { |
| 496 | do_signal32(regs); |
| 497 | return; |
| 498 | } |
| 499 | #endif |
| 500 | |
| 501 | has_handler = get_signal(&ksig); |
| 502 | |
| 503 | restart_syscall = 0; |
| 504 | if (pt_regs_is_syscall(regs) && |
| 505 | (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) { |
| 506 | restart_syscall = 1; |
| 507 | orig_i0 = regs->u_regs[UREG_G6]; |
| 508 | } |
| 509 | |
| 510 | if (has_handler) { |
| 511 | if (restart_syscall) |
| 512 | syscall_restart(orig_i0, regs, &ksig.ka.sa); |
| 513 | signal_setup_done(setup_rt_frame(&ksig, regs), &ksig, 0); |
| 514 | } else { |
| 515 | if (restart_syscall) { |
| 516 | switch (regs->u_regs[UREG_I0]) { |
| 517 | case ERESTARTNOHAND: |
| 518 | case ERESTARTSYS: |
| 519 | case ERESTARTNOINTR: |
| 520 | /* replay the system call when we are done */ |
| 521 | regs->u_regs[UREG_I0] = orig_i0; |
| 522 | regs->tpc -= 4; |
| 523 | regs->tnpc -= 4; |
| 524 | pt_regs_clear_syscall(regs); |
| 525 | case ERESTART_RESTARTBLOCK: |
| 526 | regs->u_regs[UREG_G1] = __NR_restart_syscall; |
| 527 | regs->tpc -= 4; |
| 528 | regs->tnpc -= 4; |
| 529 | pt_regs_clear_syscall(regs); |
| 530 | } |
| 531 | } |
| 532 | restore_saved_sigmask(); |
| 533 | } |
| 534 | } |
| 535 | |
| 536 | void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long thread_info_flags) |
| 537 | { |
| 538 | user_exit(); |
| 539 | if (thread_info_flags & _TIF_SIGPENDING) |
| 540 | do_signal(regs, orig_i0); |
| 541 | if (thread_info_flags & _TIF_NOTIFY_RESUME) { |
| 542 | clear_thread_flag(TIF_NOTIFY_RESUME); |
| 543 | tracehook_notify_resume(regs); |
| 544 | } |
| 545 | user_enter(); |
| 546 | } |
| 547 | |