1 // SPDX-License-Identifier: GPL-2.0 <<
2 /* 1 /*
3 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@ !! 2 * 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 <linux/tty.h>
>> 30 #include <linux/binfmts.h>
>> 31 #include <asm/ucontext.h>
>> 32 #include <asm/uaccess.h>
>> 33 #include <asm/pgtable.h>
>> 34 #include <asm/cacheflush.h>
>> 35
>> 36 #define DEBUG_SIG 0
>> 37
>> 38 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
16 39
17 EXPORT_SYMBOL(block_signals); !! 40 extern void sigreturn_exit(struct pt_regs *);
18 EXPORT_SYMBOL(unblock_signals); <<
19 41
20 void block_signals_trace(void) !! 42 #define GP_REGS_SIZE min(sizeof(elf_gregset_t), sizeof(struct pt_regs))
>> 43
>> 44 int do_signal(sigset_t *oldset, struct pt_regs *regs);
>> 45
>> 46 /*
>> 47 * Atomically swap in the new signal mask, and wait for a signal.
>> 48 */
>> 49 int
>> 50 sys_sigsuspend(old_sigset_t mask, int p2, int p3, int p4, int p6, int p7,
>> 51 struct pt_regs *regs)
21 { 52 {
22 block_signals(); !! 53 sigset_t saveset;
23 if (current_thread_info()) !! 54
24 trace_hardirqs_off(); !! 55 mask &= _BLOCKABLE;
>> 56 spin_lock_irq(¤t->sighand->siglock);
>> 57 saveset = current->blocked;
>> 58 siginitset(¤t->blocked, mask);
>> 59 recalc_sigpending();
>> 60 spin_unlock_irq(¤t->sighand->siglock);
>> 61
>> 62 regs->result = -EINTR;
>> 63 regs->gpr[3] = EINTR;
>> 64 regs->ccr |= 0x10000000;
>> 65 while (1) {
>> 66 current->state = TASK_INTERRUPTIBLE;
>> 67 schedule();
>> 68 if (do_signal(&saveset, regs))
>> 69 sigreturn_exit(regs);
>> 70 }
25 } 71 }
26 72
27 void unblock_signals_trace(void) !! 73 int
>> 74 sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize, int p3, int p4,
>> 75 int p6, int p7, struct pt_regs *regs)
28 { 76 {
29 if (current_thread_info()) !! 77 sigset_t saveset, newset;
30 trace_hardirqs_on(); !! 78
31 unblock_signals(); !! 79 /* XXX: Don't preclude handling different sized sigset_t's. */
>> 80 if (sigsetsize != sizeof(sigset_t))
>> 81 return -EINVAL;
>> 82
>> 83 if (copy_from_user(&newset, unewset, sizeof(newset)))
>> 84 return -EFAULT;
>> 85 sigdelsetmask(&newset, ~_BLOCKABLE);
>> 86
>> 87 spin_lock_irq(¤t->sighand->siglock);
>> 88 saveset = current->blocked;
>> 89 current->blocked = newset;
>> 90 recalc_sigpending();
>> 91 spin_unlock_irq(¤t->sighand->siglock);
>> 92
>> 93 regs->result = -EINTR;
>> 94 regs->gpr[3] = EINTR;
>> 95 regs->ccr |= 0x10000000;
>> 96 while (1) {
>> 97 current->state = TASK_INTERRUPTIBLE;
>> 98 schedule();
>> 99 if (do_signal(&saveset, regs))
>> 100 sigreturn_exit(regs);
>> 101 }
32 } 102 }
33 103
34 void um_trace_signals_on(void) !! 104
>> 105 int
>> 106 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, int r5,
>> 107 int r6, int r7, int r8, struct pt_regs *regs)
35 { 108 {
36 if (current_thread_info()) !! 109 return do_sigaltstack(uss, uoss, regs->gpr[1]);
37 trace_hardirqs_on(); <<
38 } 110 }
39 111
40 void um_trace_signals_off(void) !! 112 int
>> 113 sys_sigaction(int sig, const struct old_sigaction __user *act,
>> 114 struct old_sigaction __user *oact)
41 { 115 {
42 if (current_thread_info()) !! 116 struct k_sigaction new_ka, old_ka;
43 trace_hardirqs_off(); !! 117 int ret;
>> 118
>> 119 if (act) {
>> 120 old_sigset_t mask;
>> 121 if (verify_area(VERIFY_READ, act, sizeof(*act)) ||
>> 122 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
>> 123 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
>> 124 return -EFAULT;
>> 125 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
>> 126 __get_user(mask, &act->sa_mask);
>> 127 siginitset(&new_ka.sa.sa_mask, mask);
>> 128 }
>> 129
>> 130 ret = do_sigaction(sig, (act? &new_ka: NULL), (oact? &old_ka: NULL));
>> 131
>> 132 if (!ret && oact) {
>> 133 if (verify_area(VERIFY_WRITE, oact, sizeof(*oact)) ||
>> 134 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
>> 135 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
>> 136 return -EFAULT;
>> 137 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
>> 138 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
>> 139 }
>> 140
>> 141 return ret;
44 } 142 }
45 143
46 /* 144 /*
47 * OK, we're invoking a handler !! 145 * When we have signals to deliver, we set up on the
>> 146 * user stack, going down from the original stack pointer:
>> 147 * a sigregs struct
>> 148 * a sigcontext struct
>> 149 * a gap of __SIGNAL_FRAMESIZE bytes
>> 150 *
>> 151 * Each of these things must be a multiple of 16 bytes in size.
>> 152 *
>> 153 */
>> 154 struct sigregs {
>> 155 struct mcontext mctx; /* all the register values */
>> 156 /* Programs using the rs6000/xcoff abi can save up to 19 gp regs
>> 157 and 18 fp regs below sp before decrementing it. */
>> 158 int abigap[56];
>> 159 };
>> 160
>> 161 /* We use the mc_pad field for the signal return trampoline. */
>> 162 #define tramp mc_pad
>> 163
>> 164 /*
>> 165 * When we have rt signals to deliver, we set up on the
>> 166 * user stack, going down from the original stack pointer:
>> 167 * one rt_sigframe struct (siginfo + ucontext + ABI gap)
>> 168 * a gap of __SIGNAL_FRAMESIZE+16 bytes
>> 169 * (the +16 is to get the siginfo and ucontext in the same
>> 170 * positions as in older kernels).
>> 171 *
>> 172 * Each of these things must be a multiple of 16 bytes in size.
>> 173 *
48 */ 174 */
49 static void handle_signal(struct ksignal *ksig !! 175 struct rt_sigframe
50 { 176 {
51 sigset_t *oldset = sigmask_to_save(); !! 177 struct siginfo info;
52 int singlestep = 0; !! 178 struct ucontext uc;
53 unsigned long sp; !! 179 /* Programs using the rs6000/xcoff abi can save up to 19 gp regs
54 int err; !! 180 and 18 fp regs below sp before decrementing it. */
55 !! 181 int abigap[56];
56 if (test_thread_flag(TIF_SINGLESTEP) & !! 182 };
57 singlestep = 1; !! 183
58 !! 184 /*
59 /* Did we come from a system call? */ !! 185 * Save the current user registers on the user stack.
60 if (PT_REGS_SYSCALL_NR(regs) >= 0) { !! 186 * We only save the altivec registers if the process has used
61 /* If so, check system call re !! 187 * altivec instructions at some point.
62 switch (PT_REGS_SYSCALL_RET(re !! 188 */
63 case -ERESTART_RESTARTBLOCK: !! 189 static int
64 case -ERESTARTNOHAND: !! 190 save_user_regs(struct pt_regs *regs, struct mcontext *frame, int sigret)
65 PT_REGS_SYSCALL_RET(re !! 191 {
66 break; !! 192 /* save general and floating-point registers */
67 !! 193 CHECK_FULL_REGS(regs);
68 case -ERESTARTSYS: !! 194 if (regs->msr & MSR_FP)
69 if (!(ksig->ka.sa.sa_f !! 195 giveup_fpu(current);
70 PT_REGS_SYSCAL !! 196 if (__copy_to_user(&frame->mc_gregs, regs, GP_REGS_SIZE)
71 break; !! 197 || __copy_to_user(&frame->mc_fregs, current->thread.fpr,
72 } !! 198 ELF_NFPREG * sizeof(double)))
73 fallthrough; !! 199 return 1;
74 case -ERESTARTNOINTR: !! 200
75 PT_REGS_RESTART_SYSCAL !! 201 current->thread.fpscr = 0; /* turn off all fp exceptions */
76 PT_REGS_ORIG_SYSCALL(r !! 202
77 break; !! 203 #ifdef CONFIG_ALTIVEC
78 } !! 204 /* save altivec registers */
>> 205 if (current->thread.used_vr) {
>> 206 if (regs->msr & MSR_VEC)
>> 207 giveup_altivec(current);
>> 208 if (__copy_to_user(&frame->mc_vregs, current->thread.vr,
>> 209 ELF_NVRREG * sizeof(vector128)))
>> 210 return 1;
>> 211 /* set MSR_VEC in the saved MSR value to indicate that
>> 212 frame->mc_vregs contains valid data */
>> 213 if (__put_user(regs->msr | MSR_VEC, &frame->mc_gregs[PT_MSR]))
>> 214 return 1;
79 } 215 }
>> 216 /* else assert((regs->msr & MSR_VEC) == 0) */
80 217
81 sp = PT_REGS_SP(regs); !! 218 /* 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 !! 219 * use altivec. Since VSCR only contains 32 bits saved in the least
83 sp = current->sas_ss_sp + curr !! 220 * significant bits of a vector, we "cheat" and stuff VRSAVE in the
84 !! 221 * most significant bits of that same vector. --BenH
85 #ifdef CONFIG_ARCH_HAS_SC_SIGNALS !! 222 */
86 if (!(ksig->ka.sa.sa_flags & SA_SIGINF !! 223 if (__put_user(current->thread.vrsave, (u32 *)&frame->mc_vregs[32]))
87 err = setup_signal_stack_sc(sp !! 224 return 1;
88 else !! 225 #endif /* CONFIG_ALTIVEC */
>> 226
>> 227 if (sigret) {
>> 228 /* Set up the sigreturn trampoline: li r0,sigret; sc */
>> 229 if (__put_user(0x38000000UL + sigret, &frame->tramp[0])
>> 230 || __put_user(0x44000002UL, &frame->tramp[1]))
>> 231 return 1;
>> 232 flush_icache_range((unsigned long) &frame->tramp[0],
>> 233 (unsigned long) &frame->tramp[2]);
>> 234 }
>> 235
>> 236 return 0;
>> 237 }
>> 238
>> 239 /*
>> 240 * Restore the current user register values from the user stack,
>> 241 * (except for MSR).
>> 242 */
>> 243 static int
>> 244 restore_user_regs(struct pt_regs *regs, struct mcontext __user *sr)
>> 245 {
>> 246 #ifdef CONFIG_ALTIVEC
>> 247 unsigned long msr;
89 #endif 248 #endif
90 err = setup_signal_stack_si(sp <<
91 249
92 signal_setup_done(err, ksig, singleste !! 250 /* copy up to but not including MSR */
>> 251 if (__copy_from_user(regs, &sr->mc_gregs, PT_MSR * sizeof(elf_greg_t)))
>> 252 return 1;
>> 253 /* copy from orig_r3 (the word after the MSR) up to the end */
>> 254 if (__copy_from_user(®s->orig_gpr3, &sr->mc_gregs[PT_ORIG_R3],
>> 255 GP_REGS_SIZE - PT_ORIG_R3 * sizeof(elf_greg_t)))
>> 256 return 1;
>> 257
>> 258 /* force the process to reload the FP registers from
>> 259 current->thread when it next does FP instructions */
>> 260 regs->msr &= ~MSR_FP;
>> 261 if (__copy_from_user(current->thread.fpr, &sr->mc_fregs,
>> 262 sizeof(sr->mc_fregs)))
>> 263 return 1;
>> 264
>> 265 #ifdef CONFIG_ALTIVEC
>> 266 /* force the process to reload the altivec registers from
>> 267 current->thread when it next does altivec instructions */
>> 268 regs->msr &= ~MSR_VEC;
>> 269 if (!__get_user(msr, &sr->mc_gregs[PT_MSR]) && (msr & MSR_VEC) != 0) {
>> 270 /* restore altivec registers from the stack */
>> 271 if (__copy_from_user(current->thread.vr, &sr->mc_vregs,
>> 272 sizeof(sr->mc_vregs)))
>> 273 return 1;
>> 274 } else if (current->thread.used_vr)
>> 275 memset(¤t->thread.vr, 0, ELF_NVRREG * sizeof(vector128));
>> 276
>> 277 /* Always get VRSAVE back */
>> 278 if (__get_user(current->thread.vrsave, (u32 *)&sr->mc_vregs[32]))
>> 279 return 1;
>> 280 #endif /* CONFIG_ALTIVEC */
>> 281
>> 282 return 0;
93 } 283 }
94 284
95 void do_signal(struct pt_regs *regs) !! 285 /*
>> 286 * Restore the user process's signal mask
>> 287 */
>> 288 static void
>> 289 restore_sigmask(sigset_t *set)
96 { 290 {
97 struct ksignal ksig; !! 291 sigdelsetmask(set, ~_BLOCKABLE);
98 int handled_sig = 0; !! 292 spin_lock_irq(¤t->sighand->siglock);
99 !! 293 current->blocked = *set;
100 while (get_signal(&ksig)) { !! 294 recalc_sigpending();
101 handled_sig = 1; !! 295 spin_unlock_irq(¤t->sighand->siglock);
102 /* Whee! Actually deliver the !! 296 }
103 handle_signal(&ksig, regs); !! 297
104 } !! 298 /*
105 !! 299 * Set up a signal frame for a "real-time" signal handler
106 /* Did we come from a system call? */ !! 300 * (one which gets siginfo).
107 if (!handled_sig && (PT_REGS_SYSCALL_N !! 301 */
108 /* Restart the system call - n !! 302 static void
109 switch (PT_REGS_SYSCALL_RET(re !! 303 handle_rt_signal(unsigned long sig, struct k_sigaction *ka,
110 case -ERESTARTNOHAND: !! 304 siginfo_t *info, sigset_t *oldset, struct pt_regs * regs,
111 case -ERESTARTSYS: !! 305 unsigned long newsp)
112 case -ERESTARTNOINTR: !! 306 {
113 PT_REGS_ORIG_SYSCALL(r !! 307 struct rt_sigframe __user *rt_sf;
114 PT_REGS_RESTART_SYSCAL !! 308 struct mcontext __user *frame;
115 break; !! 309 unsigned long origsp = newsp;
116 case -ERESTART_RESTARTBLOCK: !! 310
117 PT_REGS_ORIG_SYSCALL(r !! 311 /* Set up Signal Frame */
118 PT_REGS_RESTART_SYSCAL !! 312 /* Put a Real Time Context onto stack */
119 break; !! 313 newsp -= sizeof(*rt_sf);
120 } !! 314 rt_sf = (struct rt_sigframe __user *) newsp;
>> 315
>> 316 /* create a stack frame for the caller of the handler */
>> 317 newsp -= __SIGNAL_FRAMESIZE + 16;
>> 318
>> 319 if (verify_area(VERIFY_WRITE, (void __user *) newsp, origsp - newsp))
>> 320 goto badframe;
>> 321
>> 322 /* Put the siginfo & fill in most of the ucontext */
>> 323 if (copy_siginfo_to_user(&rt_sf->info, info)
>> 324 || __put_user(0, &rt_sf->uc.uc_flags)
>> 325 || __put_user(0, &rt_sf->uc.uc_link)
>> 326 || __put_user(current->sas_ss_sp, &rt_sf->uc.uc_stack.ss_sp)
>> 327 || __put_user(sas_ss_flags(regs->gpr[1]),
>> 328 &rt_sf->uc.uc_stack.ss_flags)
>> 329 || __put_user(current->sas_ss_size, &rt_sf->uc.uc_stack.ss_size)
>> 330 || __put_user(&rt_sf->uc.uc_mcontext, &rt_sf->uc.uc_regs)
>> 331 || __copy_to_user(&rt_sf->uc.uc_sigmask, oldset, sizeof(*oldset)))
>> 332 goto badframe;
>> 333
>> 334 /* Save user registers on the stack */
>> 335 frame = &rt_sf->uc.uc_mcontext;
>> 336 if (save_user_regs(regs, frame, __NR_rt_sigreturn))
>> 337 goto badframe;
>> 338
>> 339 if (put_user(regs->gpr[1], (unsigned long __user *)newsp))
>> 340 goto badframe;
>> 341 regs->gpr[1] = newsp;
>> 342 regs->gpr[3] = sig;
>> 343 regs->gpr[4] = (unsigned long) &rt_sf->info;
>> 344 regs->gpr[5] = (unsigned long) &rt_sf->uc;
>> 345 regs->gpr[6] = (unsigned long) rt_sf;
>> 346 regs->nip = (unsigned long) ka->sa.sa_handler;
>> 347 regs->link = (unsigned long) frame->tramp;
>> 348 regs->trap = 0;
>> 349
>> 350 return;
>> 351
>> 352 badframe:
>> 353 #if DEBUG_SIG
>> 354 printk("badframe in handle_rt_signal, regs=%p frame=%p newsp=%lx\n",
>> 355 regs, frame, newsp);
>> 356 #endif
>> 357 if (sig == SIGSEGV)
>> 358 ka->sa.sa_handler = SIG_DFL;
>> 359 force_sig(SIGSEGV, current);
>> 360 }
>> 361
>> 362 static int do_setcontext(struct ucontext __user *ucp, struct pt_regs *regs)
>> 363 {
>> 364 sigset_t set;
>> 365 struct mcontext *mcp;
>> 366
>> 367 if (__copy_from_user(&set, &ucp->uc_sigmask, sizeof(set))
>> 368 || __get_user(mcp, &ucp->uc_regs))
>> 369 return -EFAULT;
>> 370 restore_sigmask(&set);
>> 371 if (restore_user_regs(regs, mcp))
>> 372 return -EFAULT;
>> 373
>> 374 return 0;
>> 375 }
>> 376
>> 377 int sys_swapcontext(struct ucontext __user *old_ctx,
>> 378 struct ucontext __user *new_ctx,
>> 379 int r5, int r6, int r7, int r8, struct pt_regs *regs)
>> 380 {
>> 381 unsigned char tmp;
>> 382
>> 383 if (old_ctx != NULL) {
>> 384 if (verify_area(VERIFY_WRITE, old_ctx, sizeof(*old_ctx))
>> 385 || save_user_regs(regs, &old_ctx->uc_mcontext, 0)
>> 386 || __copy_to_user(&old_ctx->uc_sigmask,
>> 387 ¤t->blocked, sizeof(sigset_t))
>> 388 || __put_user(&old_ctx->uc_mcontext, &old_ctx->uc_regs))
>> 389 return -EFAULT;
121 } 390 }
>> 391 if (new_ctx == NULL)
>> 392 return 0;
>> 393 if (verify_area(VERIFY_READ, new_ctx, sizeof(*new_ctx))
>> 394 || __get_user(tmp, (u8 *) new_ctx)
>> 395 || __get_user(tmp, (u8 *) (new_ctx + 1) - 1))
>> 396 return -EFAULT;
122 397
123 /* 398 /*
124 * if there's no signal to deliver, we !! 399 * If we get a fault copying the context into the kernel's
125 * back !! 400 * image of the user's registers, we can't just return -EFAULT
>> 401 * because the user's registers will be corrupted. For instance
>> 402 * the NIP value may have been updated but not some of the
>> 403 * other registers. Given that we have done the verify_area
>> 404 * and successfully read the first and last bytes of the region
>> 405 * above, this should only happen in an out-of-memory situation
>> 406 * or if another thread unmaps the region containing the context.
>> 407 * We kill the task with a SIGSEGV in this situation.
126 */ 408 */
127 if (!handled_sig) !! 409 if (do_setcontext(new_ctx, regs))
128 restore_saved_sigmask(); !! 410 do_exit(SIGSEGV);
>> 411 sigreturn_exit(regs);
>> 412 /* doesn't actually return back to here */
>> 413 return 0;
>> 414 }
>> 415
>> 416 int sys_rt_sigreturn(int r3, int r4, int r5, int r6, int r7, int r8,
>> 417 struct pt_regs *regs)
>> 418 {
>> 419 struct rt_sigframe __user *rt_sf;
>> 420
>> 421 /* Always make any pending restarted system calls return -EINTR */
>> 422 current_thread_info()->restart_block.fn = do_no_restart_syscall;
>> 423
>> 424 rt_sf = (struct rt_sigframe __user *)
>> 425 (regs->gpr[1] + __SIGNAL_FRAMESIZE + 16);
>> 426 if (verify_area(VERIFY_READ, rt_sf, sizeof(struct rt_sigframe)))
>> 427 goto bad;
>> 428 if (do_setcontext(&rt_sf->uc, regs))
>> 429 goto bad;
>> 430
>> 431 /*
>> 432 * It's not clear whether or why it is desirable to save the
>> 433 * sigaltstack setting on signal delivery and restore it on
>> 434 * signal return. But other architectures do this and we have
>> 435 * always done it up until now so it is probably better not to
>> 436 * change it. -- paulus
>> 437 */
>> 438 do_sigaltstack(&rt_sf->uc.uc_stack, NULL, regs->gpr[1]);
>> 439
>> 440 sigreturn_exit(regs); /* doesn't return here */
>> 441 return 0;
>> 442
>> 443 bad:
>> 444 force_sig(SIGSEGV, current);
>> 445 return 0;
>> 446 }
>> 447
>> 448 /*
>> 449 * OK, we're invoking a handler
>> 450 */
>> 451 static void
>> 452 handle_signal(unsigned long sig, struct k_sigaction *ka,
>> 453 siginfo_t *info, sigset_t *oldset, struct pt_regs * regs,
>> 454 unsigned long newsp)
>> 455 {
>> 456 struct sigcontext __user *sc;
>> 457 struct sigregs __user *frame;
>> 458 unsigned long origsp = newsp;
>> 459
>> 460 /* Set up Signal Frame */
>> 461 newsp -= sizeof(struct sigregs);
>> 462 frame = (struct sigregs __user *) newsp;
>> 463
>> 464 /* Put a sigcontext on the stack */
>> 465 newsp -= sizeof(*sc);
>> 466 sc = (struct sigcontext __user *) newsp;
>> 467
>> 468 /* create a stack frame for the caller of the handler */
>> 469 newsp -= __SIGNAL_FRAMESIZE;
>> 470
>> 471 if (verify_area(VERIFY_WRITE, (void *) newsp, origsp - newsp))
>> 472 goto badframe;
>> 473
>> 474 #if _NSIG != 64
>> 475 #error "Please adjust handle_signal()"
>> 476 #endif
>> 477 if (__put_user((unsigned long) ka->sa.sa_handler, &sc->handler)
>> 478 || __put_user(oldset->sig[0], &sc->oldmask)
>> 479 || __put_user(oldset->sig[1], &sc->_unused[3])
>> 480 || __put_user((struct pt_regs *)frame, &sc->regs)
>> 481 || __put_user(sig, &sc->signal))
>> 482 goto badframe;
>> 483
>> 484 if (save_user_regs(regs, &frame->mctx, __NR_sigreturn))
>> 485 goto badframe;
>> 486
>> 487 if (put_user(regs->gpr[1], (unsigned long *)newsp))
>> 488 goto badframe;
>> 489 regs->gpr[1] = newsp;
>> 490 regs->gpr[3] = sig;
>> 491 regs->gpr[4] = (unsigned long) sc;
>> 492 regs->nip = (unsigned long) ka->sa.sa_handler;
>> 493 regs->link = (unsigned long) frame->mctx.tramp;
>> 494 regs->trap = 0;
>> 495
>> 496 return;
>> 497
>> 498 badframe:
>> 499 #if DEBUG_SIG
>> 500 printk("badframe in handle_signal, regs=%p frame=%lx newsp=%lx\n",
>> 501 regs, frame, *newspp);
>> 502 #endif
>> 503 if (sig == SIGSEGV)
>> 504 ka->sa.sa_handler = SIG_DFL;
>> 505 force_sig(SIGSEGV, current);
129 } 506 }
>> 507
>> 508 /*
>> 509 * Do a signal return; undo the signal stack.
>> 510 */
>> 511 int sys_sigreturn(int r3, int r4, int r5, int r6, int r7, int r8,
>> 512 struct pt_regs *regs)
>> 513 {
>> 514 struct sigcontext __user *sc;
>> 515 struct sigcontext sigctx;
>> 516 struct mcontext __user *sr;
>> 517 sigset_t set;
>> 518
>> 519 /* Always make any pending restarted system calls return -EINTR */
>> 520 current_thread_info()->restart_block.fn = do_no_restart_syscall;
>> 521
>> 522 sc = (struct sigcontext __user *)(regs->gpr[1] + __SIGNAL_FRAMESIZE);
>> 523 if (copy_from_user(&sigctx, sc, sizeof(sigctx)))
>> 524 goto badframe;
>> 525
>> 526 set.sig[0] = sigctx.oldmask;
>> 527 set.sig[1] = sigctx._unused[3];
>> 528 restore_sigmask(&set);
>> 529
>> 530 sr = (struct mcontext *) sigctx.regs;
>> 531 if (verify_area(VERIFY_READ, sr, sizeof(*sr))
>> 532 || restore_user_regs(regs, sr))
>> 533 goto badframe;
>> 534
>> 535 sigreturn_exit(regs); /* doesn't return */
>> 536 return 0;
>> 537
>> 538 badframe:
>> 539 force_sig(SIGSEGV, current);
>> 540 return 0;
>> 541 }
>> 542
>> 543 /*
>> 544 * Note that 'init' is a special process: it doesn't get signals it doesn't
>> 545 * want to handle. Thus you cannot kill init even with a SIGKILL even by
>> 546 * mistake.
>> 547 */
>> 548 int do_signal(sigset_t *oldset, struct pt_regs *regs)
>> 549 {
>> 550 siginfo_t info;
>> 551 struct k_sigaction *ka;
>> 552 unsigned long frame, newsp;
>> 553 int signr, ret;
>> 554
>> 555 if (!oldset)
>> 556 oldset = ¤t->blocked;
>> 557
>> 558 newsp = frame = 0;
>> 559
>> 560 signr = get_signal_to_deliver(&info, regs, NULL);
>> 561
>> 562 ka = (signr == 0)? NULL: ¤t->sighand->action[signr-1];
>> 563
>> 564 if (TRAP(regs) == 0x0C00 /* System Call! */
>> 565 && regs->ccr & 0x10000000 /* error signalled */
>> 566 && ((ret = regs->gpr[3]) == ERESTARTSYS
>> 567 || ret == ERESTARTNOHAND || ret == ERESTARTNOINTR
>> 568 || ret == ERESTART_RESTARTBLOCK)) {
>> 569
>> 570 if (signr > 0
>> 571 && (ret == ERESTARTNOHAND || ret == ERESTART_RESTARTBLOCK
>> 572 || (ret == ERESTARTSYS
>> 573 && !(ka->sa.sa_flags & SA_RESTART)))) {
>> 574 /* make the system call return an EINTR error */
>> 575 regs->result = -EINTR;
>> 576 regs->gpr[3] = EINTR;
>> 577 /* note that the cr0.SO bit is already set */
>> 578 } else {
>> 579 regs->nip -= 4; /* Back up & retry system call */
>> 580 regs->result = 0;
>> 581 regs->trap = 0;
>> 582 if (ret == ERESTART_RESTARTBLOCK)
>> 583 regs->gpr[0] = __NR_restart_syscall;
>> 584 else
>> 585 regs->gpr[3] = regs->orig_gpr3;
>> 586 }
>> 587 }
>> 588
>> 589 if (signr == 0)
>> 590 return 0; /* no signals delivered */
>> 591
>> 592 if ((ka->sa.sa_flags & SA_ONSTACK) && current->sas_ss_size
>> 593 && !on_sig_stack(regs->gpr[1]))
>> 594 newsp = current->sas_ss_sp + current->sas_ss_size;
>> 595 else
>> 596 newsp = regs->gpr[1];
>> 597 newsp &= ~0xfUL;
>> 598
>> 599 /* Whee! Actually deliver the signal. */
>> 600 if (ka->sa.sa_flags & SA_SIGINFO)
>> 601 handle_rt_signal(signr, ka, &info, oldset, regs, newsp);
>> 602 else
>> 603 handle_signal(signr, ka, &info, oldset, regs, newsp);
>> 604
>> 605 if (ka->sa.sa_flags & SA_ONESHOT)
>> 606 ka->sa.sa_handler = SIG_DFL;
>> 607
>> 608 if (!(ka->sa.sa_flags & SA_NODEFER)) {
>> 609 spin_lock_irq(¤t->sighand->siglock);
>> 610 sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask);
>> 611 sigaddset(¤t->blocked, signr);
>> 612 recalc_sigpending();
>> 613 spin_unlock_irq(¤t->sighand->siglock);
>> 614 }
>> 615
>> 616 return 1;
>> 617 }
>> 618
130 619
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