1 // SPDX-License-Identifier: GPL-2.0 <<
2 /* 1 /*
3 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@ !! 2 * linux/arch/ppc/kernel/signal.c
>> 3 *
>> 4 * PowerPC version
>> 5 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
>> 6 *
>> 7 * Derived from "arch/i386/kernel/signal.c"
>> 8 * Copyright (C) 1991, 1992 Linus Torvalds
>> 9 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
>> 10 *
>> 11 * This program is free software; you can redistribute it and/or
>> 12 * modify it under the terms of the GNU General Public License
>> 13 * as published by the Free Software Foundation; either version
>> 14 * 2 of the License, or (at your option) any later version.
4 */ 15 */
5 16
6 #include <linux/module.h> <<
7 #include <linux/ptrace.h> <<
8 #include <linux/sched.h> 17 #include <linux/sched.h>
9 #include <linux/ftrace.h> !! 18 #include <linux/mm.h>
10 #include <asm/siginfo.h> !! 19 #include <linux/smp.h>
11 #include <asm/signal.h> !! 20 #include <linux/smp_lock.h>
12 #include <asm/unistd.h> !! 21 #include <linux/kernel.h>
13 #include <frame_kern.h> !! 22 #include <linux/signal.h>
14 #include <kern_util.h> !! 23 #include <linux/errno.h>
15 #include <os.h> !! 24 #include <linux/wait.h>
>> 25 #include <linux/ptrace.h>
>> 26 #include <linux/unistd.h>
>> 27 #include <linux/stddef.h>
>> 28 #include <linux/elf.h>
>> 29 #include <asm/ucontext.h>
>> 30 #include <asm/uaccess.h>
>> 31 #include <asm/pgtable.h>
>> 32
>> 33 #define DEBUG_SIG 0
16 34
17 EXPORT_SYMBOL(block_signals); !! 35 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
18 EXPORT_SYMBOL(unblock_signals); !! 36
>> 37 #ifndef MIN
>> 38 #define MIN(a,b) (((a) < (b)) ? (a) : (b))
>> 39 #endif
19 40
20 void block_signals_trace(void) !! 41 #define GP_REGS_SIZE MIN(sizeof(elf_gregset_t), sizeof(struct pt_regs))
>> 42
>> 43 extern void syscall_direct_return(struct pt_regs *regs);
>> 44
>> 45 int do_signal(sigset_t *oldset, struct pt_regs *regs);
>> 46
>> 47 int copy_siginfo_to_user(siginfo_t *to, siginfo_t *from)
>> 48 {
>> 49 if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
>> 50 return -EFAULT;
>> 51 if (from->si_code < 0)
>> 52 return __copy_to_user(to, from, sizeof(siginfo_t));
>> 53 else {
>> 54 int err;
>> 55
>> 56 /* If you change siginfo_t structure, please be sure
>> 57 this code is fixed accordingly.
>> 58 It should never copy any pad contained in the structure
>> 59 to avoid security leaks, but must copy the generic
>> 60 3 ints plus the relevant union member. */
>> 61 err = __put_user(from->si_signo, &to->si_signo);
>> 62 err |= __put_user(from->si_errno, &to->si_errno);
>> 63 err |= __put_user((short)from->si_code, &to->si_code);
>> 64 /* First 32bits of unions are always present. */
>> 65 err |= __put_user(from->si_pid, &to->si_pid);
>> 66 switch (from->si_code >> 16) {
>> 67 case __SI_FAULT >> 16:
>> 68 break;
>> 69 case __SI_CHLD >> 16:
>> 70 err |= __put_user(from->si_utime, &to->si_utime);
>> 71 err |= __put_user(from->si_stime, &to->si_stime);
>> 72 err |= __put_user(from->si_status, &to->si_status);
>> 73 default:
>> 74 err |= __put_user(from->si_uid, &to->si_uid);
>> 75 break;
>> 76 /* case __SI_RT: This is not generated by the kernel as of now. */
>> 77 }
>> 78 return err;
>> 79 }
>> 80 }
>> 81
>> 82 /*
>> 83 * Atomically swap in the new signal mask, and wait for a signal.
>> 84 */
>> 85 int
>> 86 sys_sigsuspend(old_sigset_t mask, int p2, int p3, int p4, int p6, int p7,
>> 87 struct pt_regs *regs)
21 { 88 {
22 block_signals(); !! 89 sigset_t saveset;
23 if (current_thread_info()) !! 90
24 trace_hardirqs_off(); !! 91 mask &= _BLOCKABLE;
>> 92 spin_lock_irq(¤t->sigmask_lock);
>> 93 saveset = current->blocked;
>> 94 siginitset(¤t->blocked, mask);
>> 95 recalc_sigpending(current);
>> 96 spin_unlock_irq(¤t->sigmask_lock);
>> 97
>> 98 regs->result = -EINTR;
>> 99 regs->gpr[3] = EINTR;
>> 100 regs->ccr |= 0x10000000;
>> 101 while (1) {
>> 102 current->state = TASK_INTERRUPTIBLE;
>> 103 schedule();
>> 104 if (do_signal(&saveset, regs))
>> 105 /*
>> 106 * If a signal handler needs to be called,
>> 107 * do_signal() has set R3 to the signal number (the
>> 108 * first argument of the signal handler), so don't
>> 109 * overwrite that with EINTR !
>> 110 * In the other cases, do_signal() doesn't touch
>> 111 * R3, so it's still set to -EINTR (see above).
>> 112 */
>> 113 return regs->gpr[3];
>> 114 }
25 } 115 }
26 116
27 void unblock_signals_trace(void) !! 117 int
>> 118 sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, int p3, int p4, int p6,
>> 119 int p7, struct pt_regs *regs)
28 { 120 {
29 if (current_thread_info()) !! 121 sigset_t saveset, newset;
30 trace_hardirqs_on(); !! 122
31 unblock_signals(); !! 123 /* XXX: Don't preclude handling different sized sigset_t's. */
>> 124 if (sigsetsize != sizeof(sigset_t))
>> 125 return -EINVAL;
>> 126
>> 127 if (copy_from_user(&newset, unewset, sizeof(newset)))
>> 128 return -EFAULT;
>> 129 sigdelsetmask(&newset, ~_BLOCKABLE);
>> 130
>> 131 spin_lock_irq(¤t->sigmask_lock);
>> 132 saveset = current->blocked;
>> 133 current->blocked = newset;
>> 134 recalc_sigpending(current);
>> 135 spin_unlock_irq(¤t->sigmask_lock);
>> 136
>> 137 regs->result = -EINTR;
>> 138 regs->gpr[3] = EINTR;
>> 139 regs->ccr |= 0x10000000;
>> 140 while (1) {
>> 141 current->state = TASK_INTERRUPTIBLE;
>> 142 schedule();
>> 143 if (do_signal(&saveset, regs))
>> 144 return regs->gpr[3];
>> 145 }
32 } 146 }
33 147
34 void um_trace_signals_on(void) !! 148
>> 149 int
>> 150 sys_sigaltstack(const stack_t *uss, stack_t *uoss, int r5, int r6,
>> 151 int r7, int r8, struct pt_regs *regs)
35 { 152 {
36 if (current_thread_info()) !! 153 return do_sigaltstack(uss, uoss, regs->gpr[1]);
37 trace_hardirqs_on(); <<
38 } 154 }
39 155
40 void um_trace_signals_off(void) !! 156 int
>> 157 sys_sigaction(int sig, const struct old_sigaction *act,
>> 158 struct old_sigaction *oact)
41 { 159 {
42 if (current_thread_info()) !! 160 struct k_sigaction new_ka, old_ka;
43 trace_hardirqs_off(); !! 161 int ret;
>> 162
>> 163 if (act) {
>> 164 old_sigset_t mask;
>> 165 if (verify_area(VERIFY_READ, act, sizeof(*act)) ||
>> 166 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
>> 167 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
>> 168 return -EFAULT;
>> 169 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
>> 170 __get_user(mask, &act->sa_mask);
>> 171 siginitset(&new_ka.sa.sa_mask, mask);
>> 172 }
>> 173
>> 174 ret = do_sigaction(sig, (act? &new_ka: NULL), (oact? &old_ka: NULL));
>> 175
>> 176 if (!ret && oact) {
>> 177 if (verify_area(VERIFY_WRITE, oact, sizeof(*oact)) ||
>> 178 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
>> 179 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
>> 180 return -EFAULT;
>> 181 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
>> 182 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
>> 183 }
>> 184
>> 185 return ret;
44 } 186 }
45 187
46 /* 188 /*
47 * OK, we're invoking a handler !! 189 * When we have signals to deliver, we set up on the
>> 190 * user stack, going down from the original stack pointer:
>> 191 * a sigregs struct
>> 192 * a sigcontext struct
>> 193 * a gap of __SIGNAL_FRAMESIZE bytes
>> 194 *
>> 195 * Each of these things must be a multiple of 16 bytes in size.
>> 196 *
>> 197 */
>> 198 struct sigregs {
>> 199 struct mcontext mctx; /* all the register values */
>> 200 /* Programs using the rs6000/xcoff abi can save up to 19 gp regs
>> 201 and 18 fp regs below sp before decrementing it. */
>> 202 int abigap[56];
>> 203 };
>> 204
>> 205 /* We use the mc_pad field for the signal return trampoline. */
>> 206 #define tramp mc_pad
>> 207
>> 208 /*
>> 209 * When we have rt signals to deliver, we set up on the
>> 210 * user stack, going down from the original stack pointer:
>> 211 * one rt_sigframe struct (siginfo + ucontext + ABI gap)
>> 212 * a gap of __SIGNAL_FRAMESIZE+16 bytes
>> 213 * (the +16 is to get the siginfo and ucontext in the same
>> 214 * positions as in older kernels).
>> 215 *
>> 216 * Each of these things must be a multiple of 16 bytes in size.
>> 217 *
48 */ 218 */
49 static void handle_signal(struct ksignal *ksig !! 219 struct rt_sigframe
50 { 220 {
51 sigset_t *oldset = sigmask_to_save(); !! 221 struct siginfo info;
52 int singlestep = 0; !! 222 struct ucontext uc;
53 unsigned long sp; !! 223 /* Programs using the rs6000/xcoff abi can save up to 19 gp regs
54 int err; !! 224 and 18 fp regs below sp before decrementing it. */
55 !! 225 int abigap[56];
56 if (test_thread_flag(TIF_SINGLESTEP) & !! 226 };
57 singlestep = 1; <<
58 <<
59 /* Did we come from a system call? */ <<
60 if (PT_REGS_SYSCALL_NR(regs) >= 0) { <<
61 /* If so, check system call re <<
62 switch (PT_REGS_SYSCALL_RET(re <<
63 case -ERESTART_RESTARTBLOCK: <<
64 case -ERESTARTNOHAND: <<
65 PT_REGS_SYSCALL_RET(re <<
66 break; <<
67 227
68 case -ERESTARTSYS: !! 228 /*
69 if (!(ksig->ka.sa.sa_f !! 229 * Save the current user registers on the user stack.
70 PT_REGS_SYSCAL !! 230 * We only save the altivec registers if the process has used
71 break; !! 231 * altivec instructions at some point.
72 } !! 232 */
73 fallthrough; !! 233 static int
74 case -ERESTARTNOINTR: !! 234 save_user_regs(struct pt_regs *regs, struct mcontext *frame, int sigret)
75 PT_REGS_RESTART_SYSCAL !! 235 {
76 PT_REGS_ORIG_SYSCALL(r !! 236 /* save general and floating-point registers */
77 break; !! 237 if (regs->msr & MSR_FP)
78 } !! 238 giveup_fpu(current);
>> 239 if (__copy_to_user(&frame->mc_gregs, regs, GP_REGS_SIZE)
>> 240 || __copy_to_user(&frame->mc_fregs, current->thread.fpr,
>> 241 ELF_NFPREG * sizeof(double)))
>> 242 return 1;
>> 243
>> 244 current->thread.fpscr = 0; /* turn off all fp exceptions */
>> 245
>> 246 #ifdef CONFIG_ALTIVEC
>> 247 /* save altivec registers */
>> 248 if (current->thread.used_vr) {
>> 249 if (regs->msr & MSR_VEC)
>> 250 giveup_altivec(current);
>> 251 if (__copy_to_user(&frame->mc_vregs, current->thread.vr,
>> 252 ELF_NVRREG * sizeof(vector128)))
>> 253 return 1;
>> 254 /* set MSR_VEC in the saved MSR value to indicate that
>> 255 frame->mc_vregs contains valid data */
>> 256 if (__put_user(regs->msr | MSR_VEC, &frame->mc_gregs[PT_MSR]))
>> 257 return 1;
79 } 258 }
>> 259 /* else assert((regs->msr & MSR_VEC) == 0) */
80 260
81 sp = PT_REGS_SP(regs); !! 261 /* We always copy to/from vrsave, it's 0 if we don't have or don't
82 if ((ksig->ka.sa.sa_flags & SA_ONSTACK !! 262 * use altivec. Since VSCR only contains 32 bits saved in the least
83 sp = current->sas_ss_sp + curr !! 263 * significant bits of a vector, we "cheat" and stuff VRSAVE in the
84 !! 264 * most significant bits of that same vector. --BenH
85 #ifdef CONFIG_ARCH_HAS_SC_SIGNALS !! 265 */
86 if (!(ksig->ka.sa.sa_flags & SA_SIGINF !! 266 if (__put_user(current->thread.vrsave, (u32 *)&frame->mc_vregs[32]))
87 err = setup_signal_stack_sc(sp !! 267 return 1;
88 else !! 268 #endif /* CONFIG_ALTIVEC */
>> 269
>> 270 if (sigret) {
>> 271 /* Set up the sigreturn trampoline: li r0,sigret; sc */
>> 272 if (__put_user(0x38000000UL + sigret, &frame->tramp[0])
>> 273 || __put_user(0x44000002UL, &frame->tramp[1]))
>> 274 return 1;
>> 275 flush_icache_range((unsigned long) &frame->tramp[0],
>> 276 (unsigned long) &frame->tramp[2]);
>> 277 }
>> 278
>> 279 return 0;
>> 280 }
>> 281
>> 282 /*
>> 283 * Restore the current user register values from the user stack,
>> 284 * (except for MSR).
>> 285 */
>> 286 static int
>> 287 restore_user_regs(struct pt_regs *regs, struct mcontext *sr)
>> 288 {
>> 289 #ifdef CONFIG_ALTIVEC
>> 290 unsigned long msr;
89 #endif 291 #endif
90 err = setup_signal_stack_si(sp <<
91 292
92 signal_setup_done(err, ksig, singleste !! 293 /* copy up to but not including MSR */
>> 294 if (__copy_from_user(regs, &sr->mc_gregs, PT_MSR * sizeof(elf_greg_t)))
>> 295 return 1;
>> 296 /* copy from orig_r3 (the word after the MSR) up to the end */
>> 297 if (__copy_from_user(®s->orig_gpr3, &sr->mc_gregs[PT_ORIG_R3],
>> 298 GP_REGS_SIZE - PT_ORIG_R3 * sizeof(elf_greg_t)))
>> 299 return 1;
>> 300
>> 301 /* force the process to reload the FP registers from
>> 302 current->thread when it next does FP instructions */
>> 303 regs->msr &= ~MSR_FP;
>> 304 if (__copy_from_user(current->thread.fpr, &sr->mc_fregs,
>> 305 sizeof(sr->mc_fregs)))
>> 306 return 1;
>> 307
>> 308 #ifdef CONFIG_ALTIVEC
>> 309 /* force the process to reload the altivec registers from
>> 310 current->thread when it next does altivec instructions */
>> 311 regs->msr &= ~MSR_VEC;
>> 312 if (!__get_user(msr, &sr->mc_gregs[PT_MSR]) && (msr & MSR_VEC) != 0) {
>> 313 /* restore altivec registers from the stack */
>> 314 if (__copy_from_user(current->thread.vr, &sr->mc_vregs,
>> 315 sizeof(sr->mc_vregs)))
>> 316 return 1;
>> 317 } else if (current->thread.used_vr)
>> 318 memset(¤t->thread.vr, 0, ELF_NVRREG * sizeof(vector128));
>> 319
>> 320 /* Always get VRSAVE back */
>> 321 if (__get_user(current->thread.vrsave, (u32 *)&sr->mc_vregs[32]))
>> 322 return 1;
>> 323 #endif /* CONFIG_ALTIVEC */
>> 324
>> 325 return 0;
93 } 326 }
94 327
95 void do_signal(struct pt_regs *regs) !! 328 /*
>> 329 * Restore the user process's signal mask
>> 330 */
>> 331 static void
>> 332 restore_sigmask(sigset_t *set)
96 { 333 {
97 struct ksignal ksig; !! 334 sigdelsetmask(set, ~_BLOCKABLE);
98 int handled_sig = 0; !! 335 spin_lock_irq(¤t->sigmask_lock);
>> 336 current->blocked = *set;
>> 337 recalc_sigpending(current);
>> 338 spin_unlock_irq(¤t->sigmask_lock);
>> 339 }
>> 340
>> 341 /*
>> 342 * Set up a signal frame for a "real-time" signal handler
>> 343 * (one which gets siginfo).
>> 344 */
>> 345 static void
>> 346 handle_rt_signal(unsigned long sig, struct k_sigaction *ka,
>> 347 siginfo_t *info, sigset_t *oldset, struct pt_regs * regs,
>> 348 unsigned long newsp)
>> 349 {
>> 350 struct rt_sigframe *rt_sf;
>> 351 struct mcontext *frame;
>> 352 unsigned long origsp = newsp;
>> 353
>> 354 /* Set up Signal Frame */
>> 355 /* Put a Real Time Context onto stack */
>> 356 newsp -= sizeof(*rt_sf);
>> 357 rt_sf = (struct rt_sigframe *) newsp;
>> 358
>> 359 /* create a stack frame for the caller of the handler */
>> 360 newsp -= __SIGNAL_FRAMESIZE + 16;
>> 361
>> 362 if (verify_area(VERIFY_WRITE, (void *) newsp, origsp - newsp))
>> 363 goto badframe;
>> 364
>> 365 /* Put the siginfo & fill in most of the ucontext */
>> 366 if (__copy_to_user(&rt_sf->info, info, sizeof(*info))
>> 367 || __put_user(0, &rt_sf->uc.uc_flags)
>> 368 || __put_user(0, &rt_sf->uc.uc_link)
>> 369 || __put_user(current->sas_ss_sp, &rt_sf->uc.uc_stack.ss_sp)
>> 370 || __put_user(sas_ss_flags(regs->gpr[1]),
>> 371 &rt_sf->uc.uc_stack.ss_flags)
>> 372 || __put_user(current->sas_ss_size, &rt_sf->uc.uc_stack.ss_size)
>> 373 || __put_user(&rt_sf->uc.uc_mcontext, &rt_sf->uc.uc_regs)
>> 374 || __copy_to_user(&rt_sf->uc.uc_sigmask, oldset, sizeof(*oldset)))
>> 375 goto badframe;
>> 376
>> 377 /* Save user registers on the stack */
>> 378 frame = &rt_sf->uc.uc_mcontext;
>> 379 if (save_user_regs(regs, frame, 0x6666))
>> 380 goto badframe;
>> 381
>> 382 if (put_user(regs->gpr[1], (unsigned long *)newsp))
>> 383 goto badframe;
>> 384 regs->gpr[1] = newsp;
>> 385 regs->gpr[3] = sig;
>> 386 regs->gpr[4] = (unsigned long) &rt_sf->info;
>> 387 regs->gpr[5] = (unsigned long) &rt_sf->uc;
>> 388 regs->gpr[6] = (unsigned long) rt_sf;
>> 389 regs->nip = (unsigned long) ka->sa.sa_handler;
>> 390 regs->link = (unsigned long) frame->tramp;
>> 391
>> 392 return;
>> 393
>> 394 badframe:
>> 395 #if DEBUG_SIG
>> 396 printk("badframe in handle_rt_signal, regs=%p frame=%p newsp=%lx\n",
>> 397 regs, frame, newsp);
>> 398 #endif
>> 399 if (sig == SIGSEGV)
>> 400 ka->sa.sa_handler = SIG_DFL;
>> 401 force_sig(SIGSEGV, current);
>> 402 }
>> 403
>> 404 static int do_setcontext(struct ucontext *ucp, struct pt_regs *regs)
>> 405 {
>> 406 sigset_t set;
>> 407 struct mcontext *mcp;
>> 408
>> 409 if (__copy_from_user(&set, &ucp->uc_sigmask, sizeof(set))
>> 410 || __get_user(mcp, &ucp->uc_regs))
>> 411 return -EFAULT;
>> 412 restore_sigmask(&set);
>> 413 if (restore_user_regs(regs, mcp))
>> 414 return -EFAULT;
>> 415
>> 416 return 0;
>> 417 }
99 418
100 while (get_signal(&ksig)) { !! 419 int sys_swapcontext(struct ucontext *old_ctx, struct ucontext *new_ctx,
101 handled_sig = 1; !! 420 int r5, int r6, int r7, int r8, struct pt_regs *regs)
102 /* Whee! Actually deliver the !! 421 {
103 handle_signal(&ksig, regs); !! 422 unsigned char tmp;
>> 423
>> 424 if (old_ctx != NULL) {
>> 425 if (verify_area(VERIFY_WRITE, old_ctx, sizeof(*old_ctx))
>> 426 || save_user_regs(regs, &old_ctx->uc_mcontext, 0)
>> 427 || __copy_to_user(&old_ctx->uc_sigmask,
>> 428 ¤t->blocked, sizeof(sigset_t))
>> 429 || __put_user(&old_ctx->uc_mcontext, &old_ctx->uc_regs))
>> 430 return -EFAULT;
104 } 431 }
>> 432 if (new_ctx == NULL)
>> 433 return 0;
>> 434 if (verify_area(VERIFY_READ, new_ctx, sizeof(*new_ctx))
>> 435 || __get_user(tmp, (u8 *) new_ctx)
>> 436 || __get_user(tmp, (u8 *) (new_ctx + 1) - 1))
>> 437 return -EFAULT;
105 438
106 /* Did we come from a system call? */ !! 439 /*
107 if (!handled_sig && (PT_REGS_SYSCALL_N !! 440 * If we get a fault copying the context into the kernel's
108 /* Restart the system call - n !! 441 * image of the user's registers, we can't just return -EFAULT
109 switch (PT_REGS_SYSCALL_RET(re !! 442 * because the user's registers will be corrupted. For instance
110 case -ERESTARTNOHAND: !! 443 * the NIP value may have been updated but not some of the
>> 444 * other registers. Given that we have done the verify_area
>> 445 * and successfully read the first and last bytes of the region
>> 446 * above, this should only happen in an out-of-memory situation
>> 447 * or if another thread unmaps the region containing the context.
>> 448 * We kill the task with a SIGSEGV in this situation.
>> 449 */
>> 450 if (do_setcontext(new_ctx, regs))
>> 451 do_exit(SIGSEGV);
>> 452 syscall_direct_return(regs);
>> 453 /* doesn't actually return back to here */
>> 454 return 0;
>> 455 }
>> 456
>> 457 int sys_rt_sigreturn(struct pt_regs *regs)
>> 458 {
>> 459 struct rt_sigframe *rt_sf;
>> 460 stack_t st;
>> 461
>> 462 rt_sf = (struct rt_sigframe *)(regs->gpr[1] + __SIGNAL_FRAMESIZE + 16);
>> 463 if (verify_area(VERIFY_READ, rt_sf, sizeof(struct rt_sigframe)))
>> 464 goto bad;
>> 465 if (do_setcontext(&rt_sf->uc, regs))
>> 466 goto bad;
>> 467
>> 468 /*
>> 469 * It's not clear whether or why it is desirable to save the
>> 470 * sigaltstack setting on signal delivery and restore it on
>> 471 * signal return. But other architectures do this and we have
>> 472 * always done it up until now so it is probably better not to
>> 473 * change it. -- paulus
>> 474 */
>> 475 if (__copy_from_user(&st, &rt_sf->uc.uc_stack, sizeof(st)))
>> 476 goto bad;
>> 477 do_sigaltstack(&st, NULL, regs->gpr[1]);
>> 478
>> 479 return regs->result;
>> 480
>> 481 bad:
>> 482 force_sig(SIGSEGV, current);
>> 483 return 0;
>> 484 }
>> 485
>> 486 /*
>> 487 * OK, we're invoking a handler
>> 488 */
>> 489 static void
>> 490 handle_signal(unsigned long sig, struct k_sigaction *ka,
>> 491 siginfo_t *info, sigset_t *oldset, struct pt_regs * regs,
>> 492 unsigned long newsp)
>> 493 {
>> 494 struct sigcontext *sc;
>> 495 struct sigregs *frame;
>> 496 unsigned long origsp = newsp;
>> 497
>> 498 /* Set up Signal Frame */
>> 499 newsp -= sizeof(struct sigregs);
>> 500 frame = (struct sigregs *) newsp;
>> 501
>> 502 /* Put a sigcontext on the stack */
>> 503 newsp -= sizeof(*sc);
>> 504 sc = (struct sigcontext *) newsp;
>> 505
>> 506 /* create a stack frame for the caller of the handler */
>> 507 newsp -= __SIGNAL_FRAMESIZE;
>> 508
>> 509 if (verify_area(VERIFY_WRITE, (void *) newsp, origsp - newsp))
>> 510 goto badframe;
>> 511
>> 512 #if _NSIG != 64
>> 513 #error "Please adjust handle_signal()"
>> 514 #endif
>> 515 if (__put_user((unsigned long) ka->sa.sa_handler, &sc->handler)
>> 516 || __put_user(oldset->sig[0], &sc->oldmask)
>> 517 || __put_user(oldset->sig[1], &sc->_unused[3])
>> 518 || __put_user((struct pt_regs *)frame, &sc->regs)
>> 519 || __put_user(sig, &sc->signal))
>> 520 goto badframe;
>> 521
>> 522 if (save_user_regs(regs, &frame->mctx, 0x7777))
>> 523 goto badframe;
>> 524
>> 525 if (put_user(regs->gpr[1], (unsigned long *)newsp))
>> 526 goto badframe;
>> 527 regs->gpr[1] = newsp;
>> 528 regs->gpr[3] = sig;
>> 529 regs->gpr[4] = (unsigned long) sc;
>> 530 regs->nip = (unsigned long) ka->sa.sa_handler;
>> 531 regs->link = (unsigned long) frame->mctx.tramp;
>> 532
>> 533 return;
>> 534
>> 535 badframe:
>> 536 #if DEBUG_SIG
>> 537 printk("badframe in handle_signal, regs=%p frame=%lx newsp=%lx\n",
>> 538 regs, frame, *newspp);
>> 539 #endif
>> 540 if (sig == SIGSEGV)
>> 541 ka->sa.sa_handler = SIG_DFL;
>> 542 force_sig(SIGSEGV, current);
>> 543 }
>> 544
>> 545 /*
>> 546 * Do a signal return; undo the signal stack.
>> 547 */
>> 548 int sys_sigreturn(struct pt_regs *regs)
>> 549 {
>> 550 struct sigcontext *sc, sigctx;
>> 551 struct mcontext *sr;
>> 552 int ret;
>> 553 sigset_t set;
>> 554
>> 555 sc = (struct sigcontext *)(regs->gpr[1] + __SIGNAL_FRAMESIZE);
>> 556 if (copy_from_user(&sigctx, sc, sizeof(sigctx)))
>> 557 goto badframe;
>> 558
>> 559 set.sig[0] = sigctx.oldmask;
>> 560 set.sig[1] = sigctx._unused[3];
>> 561 restore_sigmask(&set);
>> 562
>> 563 sr = (struct mcontext *) sigctx.regs;
>> 564 if (verify_area(VERIFY_READ, sr, sizeof(*sr))
>> 565 || restore_user_regs(regs, sr))
>> 566 goto badframe;
>> 567
>> 568 ret = regs->result;
>> 569
>> 570 return ret;
>> 571
>> 572 badframe:
>> 573 force_sig(SIGSEGV, current);
>> 574 return 0;
>> 575 }
>> 576
>> 577 static int get_signal_to_deliver(struct siginfo *infop, struct pt_regs *regs)
>> 578 {
>> 579 struct k_sigaction *ka;
>> 580 int signr;
>> 581
>> 582 for (;;) {
>> 583 spin_lock_irq(¤t->sigmask_lock);
>> 584 signr = dequeue_signal(¤t->blocked, infop);
>> 585 spin_unlock_irq(¤t->sigmask_lock);
>> 586
>> 587 if (!signr)
>> 588 return 0;
>> 589
>> 590 if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) {
>> 591 /* Let the debugger run. */
>> 592 current->exit_code = signr;
>> 593 current->state = TASK_STOPPED;
>> 594 notify_parent(current, SIGCHLD);
>> 595 schedule();
>> 596
>> 597 /* We're back. Did the debugger cancel the sig? */
>> 598 if (!(signr = current->exit_code))
>> 599 continue;
>> 600 current->exit_code = 0;
>> 601
>> 602 /* The debugger continued. Ignore SIGSTOP. */
>> 603 if (signr == SIGSTOP)
>> 604 continue;
>> 605
>> 606 /* Update the siginfo structure. Is this good? */
>> 607 if (signr != infop->si_signo) {
>> 608 infop->si_signo = signr;
>> 609 infop->si_errno = 0;
>> 610 infop->si_code = SI_USER;
>> 611 infop->si_pid = current->p_pptr->pid;
>> 612 infop->si_uid = current->p_pptr->uid;
>> 613 }
>> 614
>> 615 /* If the (new) signal is now blocked, requeue it. */
>> 616 if (sigismember(¤t->blocked, signr)) {
>> 617 send_sig_info(signr, infop, current);
>> 618 continue;
>> 619 }
>> 620 }
>> 621
>> 622 ka = ¤t->sig->action[signr-1];
>> 623 if (ka->sa.sa_handler == SIG_IGN) {
>> 624 if (signr != SIGCHLD)
>> 625 continue;
>> 626 /* Check for SIGCHLD: it's special. */
>> 627 while (sys_wait4(-1, NULL, WNOHANG, NULL) > 0)
>> 628 /* nothing */;
>> 629 continue;
>> 630 }
>> 631
>> 632 if (ka->sa.sa_handler == SIG_DFL) {
>> 633 int exit_code = signr;
>> 634
>> 635 /* Init gets no signals it doesn't want. */
>> 636 if (current->pid == 1)
>> 637 continue;
>> 638
>> 639 switch (signr) {
>> 640 case SIGCONT: case SIGCHLD: case SIGWINCH: case SIGURG:
>> 641 continue;
>> 642
>> 643 case SIGTSTP: case SIGTTIN: case SIGTTOU:
>> 644 if (is_orphaned_pgrp(current->pgrp))
>> 645 continue;
>> 646 /* FALLTHRU */
>> 647
>> 648 case SIGSTOP:
>> 649 current->state = TASK_STOPPED;
>> 650 current->exit_code = signr;
>> 651 if (!(current->p_pptr->sig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
>> 652 notify_parent(current, SIGCHLD);
>> 653 schedule();
>> 654 continue;
>> 655
>> 656 case SIGQUIT: case SIGILL: case SIGTRAP:
>> 657 case SIGABRT: case SIGFPE: case SIGSEGV:
>> 658 case SIGBUS: case SIGSYS: case SIGXCPU: case SIGXFSZ:
>> 659 if (do_coredump(signr, regs))
>> 660 exit_code |= 0x80;
>> 661 /* FALLTHRU */
>> 662
>> 663 default:
>> 664 sig_exit(signr, exit_code, infop);
>> 665 /* NOTREACHED */
>> 666 }
>> 667 }
>> 668 return signr;
>> 669 }
>> 670 }
>> 671
>> 672 /*
>> 673 * Note that 'init' is a special process: it doesn't get signals it doesn't
>> 674 * want to handle. Thus you cannot kill init even with a SIGKILL even by
>> 675 * mistake.
>> 676 */
>> 677 int do_signal(sigset_t *oldset, struct pt_regs *regs)
>> 678 {
>> 679 siginfo_t info;
>> 680 struct k_sigaction *ka;
>> 681 unsigned long frame, newsp;
>> 682 int signr;
>> 683
>> 684 if (!oldset)
>> 685 oldset = ¤t->blocked;
>> 686
>> 687 newsp = frame = 0;
>> 688
>> 689 signr = get_signal_to_deliver(&info, regs);
>> 690
>> 691 ka = (signr == 0)? NULL: ¤t->sig->action[signr-1];
>> 692
>> 693 if (regs->trap == 0xc00) { /* system call */
>> 694 switch ((int) regs->result) {
111 case -ERESTARTSYS: 695 case -ERESTARTSYS:
>> 696 if (signr == 0 || (ka->sa.sa_flags & SA_RESTART))
>> 697 goto retry;
>> 698 /* fall through */
>> 699 case -ERESTARTNOHAND:
>> 700 if (signr > 0) {
>> 701 /* make the system call return an EINTR */
>> 702 regs->result = -EINTR;
>> 703 break;
>> 704 }
>> 705 /* fall through */
112 case -ERESTARTNOINTR: 706 case -ERESTARTNOINTR:
113 PT_REGS_ORIG_SYSCALL(r !! 707 retry:
114 PT_REGS_RESTART_SYSCAL !! 708 /* Back up & retry system call */
115 break; !! 709 regs->gpr[3] = regs->orig_gpr3;
116 case -ERESTART_RESTARTBLOCK: !! 710 regs->nip -= 4;
117 PT_REGS_ORIG_SYSCALL(r !! 711 regs->result = 0;
118 PT_REGS_RESTART_SYSCAL <<
119 break; 712 break;
120 } 713 }
121 } 714 }
122 715
123 /* !! 716 if (signr == 0)
124 * if there's no signal to deliver, we !! 717 return 0; /* no signals delivered */
125 * back !! 718
126 */ !! 719 if ((ka->sa.sa_flags & SA_ONSTACK) && current->sas_ss_size
127 if (!handled_sig) !! 720 && !on_sig_stack(regs->gpr[1]))
128 restore_saved_sigmask(); !! 721 newsp = current->sas_ss_sp + current->sas_ss_size;
>> 722 else
>> 723 newsp = regs->gpr[1];
>> 724 newsp &= ~0xfUL;
>> 725
>> 726 /* Whee! Actually deliver the signal. */
>> 727 if (ka->sa.sa_flags & SA_SIGINFO)
>> 728 handle_rt_signal(signr, ka, &info, oldset, regs, newsp);
>> 729 else
>> 730 handle_signal(signr, ka, &info, oldset, regs, newsp);
>> 731
>> 732 if (ka->sa.sa_flags & SA_ONESHOT)
>> 733 ka->sa.sa_handler = SIG_DFL;
>> 734
>> 735 if (!(ka->sa.sa_flags & SA_NODEFER)) {
>> 736 spin_lock_irq(¤t->sigmask_lock);
>> 737 sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask);
>> 738 sigaddset(¤t->blocked, signr);
>> 739 recalc_sigpending(current);
>> 740 spin_unlock_irq(¤t->sigmask_lock);
>> 741 }
>> 742
>> 743 return 1;
129 } 744 }
>> 745
130 746
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