1 // SPDX-License-Identifier: GPL-2.0 1 // SPDX-License-Identifier: GPL-2.0
2 /* 2 /*
3 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@ !! 3 * linux/arch/alpha/kernel/signal.c
>> 4 *
>> 5 * Copyright (C) 1995 Linus Torvalds
>> 6 *
>> 7 * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
4 */ 8 */
5 9
6 #include <linux/module.h> !! 10 #include <linux/sched/signal.h>
>> 11 #include <linux/sched/task_stack.h>
>> 12 #include <linux/kernel.h>
>> 13 #include <linux/signal.h>
>> 14 #include <linux/errno.h>
>> 15 #include <linux/wait.h>
7 #include <linux/ptrace.h> 16 #include <linux/ptrace.h>
8 #include <linux/sched.h> !! 17 #include <linux/unistd.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/stddef.h>
12 #include <asm/unistd.h> !! 21 #include <linux/tty.h>
13 #include <frame_kern.h> !! 22 #include <linux/binfmts.h>
14 #include <kern_util.h> !! 23 #include <linux/bitops.h>
15 #include <os.h> !! 24 #include <linux/syscalls.h>
>> 25 #include <linux/resume_user_mode.h>
16 26
17 EXPORT_SYMBOL(block_signals); !! 27 #include <linux/uaccess.h>
18 EXPORT_SYMBOL(unblock_signals); !! 28 #include <asm/sigcontext.h>
>> 29 #include <asm/ucontext.h>
19 30
20 void block_signals_trace(void) !! 31 #include "proto.h"
>> 32
>> 33
>> 34 #define DEBUG_SIG 0
>> 35
>> 36 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
>> 37
>> 38 asmlinkage void ret_from_sys_call(void);
>> 39
>> 40 /*
>> 41 * The OSF/1 sigprocmask calling sequence is different from the
>> 42 * C sigprocmask() sequence..
>> 43 */
>> 44 SYSCALL_DEFINE2(osf_sigprocmask, int, how, unsigned long, newmask)
21 { 45 {
22 block_signals(); !! 46 sigset_t oldmask;
23 if (current_thread_info()) !! 47 sigset_t mask;
24 trace_hardirqs_off(); !! 48 unsigned long res;
>> 49
>> 50 siginitset(&mask, newmask & _BLOCKABLE);
>> 51 res = sigprocmask(how, &mask, &oldmask);
>> 52 if (!res) {
>> 53 force_successful_syscall_return();
>> 54 res = oldmask.sig[0];
>> 55 }
>> 56 return res;
>> 57 }
>> 58
>> 59 SYSCALL_DEFINE3(osf_sigaction, int, sig,
>> 60 const struct osf_sigaction __user *, act,
>> 61 struct osf_sigaction __user *, oact)
>> 62 {
>> 63 struct k_sigaction new_ka, old_ka;
>> 64 int ret;
>> 65
>> 66 if (act) {
>> 67 old_sigset_t mask;
>> 68 if (!access_ok(act, sizeof(*act)) ||
>> 69 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
>> 70 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
>> 71 __get_user(mask, &act->sa_mask))
>> 72 return -EFAULT;
>> 73 siginitset(&new_ka.sa.sa_mask, mask);
>> 74 new_ka.ka_restorer = NULL;
>> 75 }
>> 76
>> 77 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
>> 78
>> 79 if (!ret && oact) {
>> 80 if (!access_ok(oact, sizeof(*oact)) ||
>> 81 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
>> 82 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
>> 83 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
>> 84 return -EFAULT;
>> 85 }
>> 86
>> 87 return ret;
>> 88 }
>> 89
>> 90 SYSCALL_DEFINE5(rt_sigaction, int, sig, const struct sigaction __user *, act,
>> 91 struct sigaction __user *, oact,
>> 92 size_t, sigsetsize, void __user *, restorer)
>> 93 {
>> 94 struct k_sigaction new_ka, old_ka;
>> 95 int ret;
>> 96
>> 97 /* XXX: Don't preclude handling different sized sigset_t's. */
>> 98 if (sigsetsize != sizeof(sigset_t))
>> 99 return -EINVAL;
>> 100
>> 101 if (act) {
>> 102 new_ka.ka_restorer = restorer;
>> 103 if (copy_from_user(&new_ka.sa, act, sizeof(*act)))
>> 104 return -EFAULT;
>> 105 }
>> 106
>> 107 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
>> 108
>> 109 if (!ret && oact) {
>> 110 if (copy_to_user(oact, &old_ka.sa, sizeof(*oact)))
>> 111 return -EFAULT;
>> 112 }
>> 113
>> 114 return ret;
25 } 115 }
26 116
27 void unblock_signals_trace(void) !! 117 /*
>> 118 * Do a signal return; undo the signal stack.
>> 119 */
>> 120
>> 121 #if _NSIG_WORDS > 1
>> 122 # error "Non SA_SIGINFO frame needs rearranging"
>> 123 #endif
>> 124
>> 125 struct sigframe
28 { 126 {
29 if (current_thread_info()) !! 127 struct sigcontext sc;
30 trace_hardirqs_on(); !! 128 unsigned int retcode[3];
31 unblock_signals(); !! 129 };
>> 130
>> 131 struct rt_sigframe
>> 132 {
>> 133 struct siginfo info;
>> 134 struct ucontext uc;
>> 135 unsigned int retcode[3];
>> 136 };
>> 137
>> 138 /* If this changes, userland unwinders that Know Things about our signal
>> 139 frame will break. Do not undertake lightly. It also implies an ABI
>> 140 change wrt the size of siginfo_t, which may cause some pain. */
>> 141 extern char compile_time_assert
>> 142 [offsetof(struct rt_sigframe, uc.uc_mcontext) == 176 ? 1 : -1];
>> 143
>> 144 #define INSN_MOV_R30_R16 0x47fe0410
>> 145 #define INSN_LDI_R0 0x201f0000
>> 146 #define INSN_CALLSYS 0x00000083
>> 147
>> 148 static long
>> 149 restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
>> 150 {
>> 151 unsigned long usp;
>> 152 struct switch_stack *sw = (struct switch_stack *)regs - 1;
>> 153 long err = __get_user(regs->pc, &sc->sc_pc);
>> 154
>> 155 current->restart_block.fn = do_no_restart_syscall;
>> 156 current_thread_info()->status |= TS_SAVED_FP | TS_RESTORE_FP;
>> 157
>> 158 sw->r26 = (unsigned long) ret_from_sys_call;
>> 159
>> 160 err |= __get_user(regs->r0, sc->sc_regs+0);
>> 161 err |= __get_user(regs->r1, sc->sc_regs+1);
>> 162 err |= __get_user(regs->r2, sc->sc_regs+2);
>> 163 err |= __get_user(regs->r3, sc->sc_regs+3);
>> 164 err |= __get_user(regs->r4, sc->sc_regs+4);
>> 165 err |= __get_user(regs->r5, sc->sc_regs+5);
>> 166 err |= __get_user(regs->r6, sc->sc_regs+6);
>> 167 err |= __get_user(regs->r7, sc->sc_regs+7);
>> 168 err |= __get_user(regs->r8, sc->sc_regs+8);
>> 169 err |= __get_user(sw->r9, sc->sc_regs+9);
>> 170 err |= __get_user(sw->r10, sc->sc_regs+10);
>> 171 err |= __get_user(sw->r11, sc->sc_regs+11);
>> 172 err |= __get_user(sw->r12, sc->sc_regs+12);
>> 173 err |= __get_user(sw->r13, sc->sc_regs+13);
>> 174 err |= __get_user(sw->r14, sc->sc_regs+14);
>> 175 err |= __get_user(sw->r15, sc->sc_regs+15);
>> 176 err |= __get_user(regs->r16, sc->sc_regs+16);
>> 177 err |= __get_user(regs->r17, sc->sc_regs+17);
>> 178 err |= __get_user(regs->r18, sc->sc_regs+18);
>> 179 err |= __get_user(regs->r19, sc->sc_regs+19);
>> 180 err |= __get_user(regs->r20, sc->sc_regs+20);
>> 181 err |= __get_user(regs->r21, sc->sc_regs+21);
>> 182 err |= __get_user(regs->r22, sc->sc_regs+22);
>> 183 err |= __get_user(regs->r23, sc->sc_regs+23);
>> 184 err |= __get_user(regs->r24, sc->sc_regs+24);
>> 185 err |= __get_user(regs->r25, sc->sc_regs+25);
>> 186 err |= __get_user(regs->r26, sc->sc_regs+26);
>> 187 err |= __get_user(regs->r27, sc->sc_regs+27);
>> 188 err |= __get_user(regs->r28, sc->sc_regs+28);
>> 189 err |= __get_user(regs->gp, sc->sc_regs+29);
>> 190 err |= __get_user(usp, sc->sc_regs+30);
>> 191 wrusp(usp);
>> 192
>> 193 err |= __copy_from_user(current_thread_info()->fp,
>> 194 sc->sc_fpregs, 31 * 8);
>> 195 err |= __get_user(current_thread_info()->fp[31], &sc->sc_fpcr);
>> 196
>> 197 return err;
32 } 198 }
33 199
34 void um_trace_signals_on(void) !! 200 /* Note that this syscall is also used by setcontext(3) to install
>> 201 a given sigcontext. This because it's impossible to set *all*
>> 202 registers and transfer control from userland. */
>> 203
>> 204 asmlinkage void
>> 205 do_sigreturn(struct sigcontext __user *sc)
35 { 206 {
36 if (current_thread_info()) !! 207 struct pt_regs *regs = current_pt_regs();
37 trace_hardirqs_on(); !! 208 sigset_t set;
>> 209
>> 210 /* Verify that it's a good sigcontext before using it */
>> 211 if (!access_ok(sc, sizeof(*sc)))
>> 212 goto give_sigsegv;
>> 213 if (__get_user(set.sig[0], &sc->sc_mask))
>> 214 goto give_sigsegv;
>> 215
>> 216 set_current_blocked(&set);
>> 217
>> 218 if (restore_sigcontext(sc, regs))
>> 219 goto give_sigsegv;
>> 220
>> 221 /* Send SIGTRAP if we're single-stepping: */
>> 222 if (ptrace_cancel_bpt (current)) {
>> 223 send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *) regs->pc,
>> 224 current);
>> 225 }
>> 226 return;
>> 227
>> 228 give_sigsegv:
>> 229 force_sig(SIGSEGV);
38 } 230 }
39 231
40 void um_trace_signals_off(void) !! 232 asmlinkage void
>> 233 do_rt_sigreturn(struct rt_sigframe __user *frame)
41 { 234 {
42 if (current_thread_info()) !! 235 struct pt_regs *regs = current_pt_regs();
43 trace_hardirqs_off(); !! 236 sigset_t set;
>> 237
>> 238 /* Verify that it's a good ucontext_t before using it */
>> 239 if (!access_ok(&frame->uc, sizeof(frame->uc)))
>> 240 goto give_sigsegv;
>> 241 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
>> 242 goto give_sigsegv;
>> 243
>> 244 set_current_blocked(&set);
>> 245
>> 246 if (restore_sigcontext(&frame->uc.uc_mcontext, regs))
>> 247 goto give_sigsegv;
>> 248
>> 249 /* Send SIGTRAP if we're single-stepping: */
>> 250 if (ptrace_cancel_bpt (current)) {
>> 251 send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *) regs->pc,
>> 252 current);
>> 253 }
>> 254 return;
>> 255
>> 256 give_sigsegv:
>> 257 force_sig(SIGSEGV);
44 } 258 }
45 259
>> 260
46 /* 261 /*
47 * OK, we're invoking a handler !! 262 * Set up a signal frame.
48 */ 263 */
49 static void handle_signal(struct ksignal *ksig !! 264
>> 265 static inline void __user *
>> 266 get_sigframe(struct ksignal *ksig, unsigned long sp, size_t frame_size)
50 { 267 {
51 sigset_t *oldset = sigmask_to_save(); !! 268 return (void __user *)((sigsp(sp, ksig) - frame_size) & -32ul);
52 int singlestep = 0; !! 269 }
53 unsigned long sp; <<
54 int err; <<
55 <<
56 if (test_thread_flag(TIF_SINGLESTEP) & <<
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; <<
67 270
68 case -ERESTARTSYS: !! 271 static long
69 if (!(ksig->ka.sa.sa_f !! 272 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
70 PT_REGS_SYSCAL !! 273 unsigned long mask, unsigned long sp)
71 break; !! 274 {
72 } !! 275 struct switch_stack *sw = (struct switch_stack *)regs - 1;
73 fallthrough; !! 276 long err = 0;
74 case -ERESTARTNOINTR: !! 277
75 PT_REGS_RESTART_SYSCAL !! 278 err |= __put_user(on_sig_stack((unsigned long)sc), &sc->sc_onstack);
76 PT_REGS_ORIG_SYSCALL(r !! 279 err |= __put_user(mask, &sc->sc_mask);
77 break; !! 280 err |= __put_user(regs->pc, &sc->sc_pc);
78 } !! 281 err |= __put_user(8, &sc->sc_ps);
>> 282
>> 283 err |= __put_user(regs->r0 , sc->sc_regs+0);
>> 284 err |= __put_user(regs->r1 , sc->sc_regs+1);
>> 285 err |= __put_user(regs->r2 , sc->sc_regs+2);
>> 286 err |= __put_user(regs->r3 , sc->sc_regs+3);
>> 287 err |= __put_user(regs->r4 , sc->sc_regs+4);
>> 288 err |= __put_user(regs->r5 , sc->sc_regs+5);
>> 289 err |= __put_user(regs->r6 , sc->sc_regs+6);
>> 290 err |= __put_user(regs->r7 , sc->sc_regs+7);
>> 291 err |= __put_user(regs->r8 , sc->sc_regs+8);
>> 292 err |= __put_user(sw->r9 , sc->sc_regs+9);
>> 293 err |= __put_user(sw->r10 , sc->sc_regs+10);
>> 294 err |= __put_user(sw->r11 , sc->sc_regs+11);
>> 295 err |= __put_user(sw->r12 , sc->sc_regs+12);
>> 296 err |= __put_user(sw->r13 , sc->sc_regs+13);
>> 297 err |= __put_user(sw->r14 , sc->sc_regs+14);
>> 298 err |= __put_user(sw->r15 , sc->sc_regs+15);
>> 299 err |= __put_user(regs->r16, sc->sc_regs+16);
>> 300 err |= __put_user(regs->r17, sc->sc_regs+17);
>> 301 err |= __put_user(regs->r18, sc->sc_regs+18);
>> 302 err |= __put_user(regs->r19, sc->sc_regs+19);
>> 303 err |= __put_user(regs->r20, sc->sc_regs+20);
>> 304 err |= __put_user(regs->r21, sc->sc_regs+21);
>> 305 err |= __put_user(regs->r22, sc->sc_regs+22);
>> 306 err |= __put_user(regs->r23, sc->sc_regs+23);
>> 307 err |= __put_user(regs->r24, sc->sc_regs+24);
>> 308 err |= __put_user(regs->r25, sc->sc_regs+25);
>> 309 err |= __put_user(regs->r26, sc->sc_regs+26);
>> 310 err |= __put_user(regs->r27, sc->sc_regs+27);
>> 311 err |= __put_user(regs->r28, sc->sc_regs+28);
>> 312 err |= __put_user(regs->gp , sc->sc_regs+29);
>> 313 err |= __put_user(sp, sc->sc_regs+30);
>> 314 err |= __put_user(0, sc->sc_regs+31);
>> 315
>> 316 err |= __copy_to_user(sc->sc_fpregs,
>> 317 current_thread_info()->fp, 31 * 8);
>> 318 err |= __put_user(0, sc->sc_fpregs+31);
>> 319 err |= __put_user(current_thread_info()->fp[31], &sc->sc_fpcr);
>> 320
>> 321 err |= __put_user(regs->trap_a0, &sc->sc_traparg_a0);
>> 322 err |= __put_user(regs->trap_a1, &sc->sc_traparg_a1);
>> 323 err |= __put_user(regs->trap_a2, &sc->sc_traparg_a2);
>> 324
>> 325 return err;
>> 326 }
>> 327
>> 328 static int
>> 329 setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
>> 330 {
>> 331 unsigned long oldsp, r26, err = 0;
>> 332 struct sigframe __user *frame;
>> 333
>> 334 oldsp = rdusp();
>> 335 frame = get_sigframe(ksig, oldsp, sizeof(*frame));
>> 336 if (!access_ok(frame, sizeof(*frame)))
>> 337 return -EFAULT;
>> 338
>> 339 err |= setup_sigcontext(&frame->sc, regs, set->sig[0], oldsp);
>> 340 if (err)
>> 341 return -EFAULT;
>> 342
>> 343 /* Set up to return from userspace. If provided, use a stub
>> 344 already in userspace. */
>> 345 r26 = (unsigned long) ksig->ka.ka_restorer;
>> 346 if (!r26) {
>> 347 err |= __put_user(INSN_MOV_R30_R16, frame->retcode+0);
>> 348 err |= __put_user(INSN_LDI_R0+__NR_sigreturn, frame->retcode+1);
>> 349 err |= __put_user(INSN_CALLSYS, frame->retcode+2);
>> 350 imb();
>> 351 r26 = (unsigned long) frame->retcode;
79 } 352 }
80 353
81 sp = PT_REGS_SP(regs); !! 354 /* Check that everything was written properly. */
82 if ((ksig->ka.sa.sa_flags & SA_ONSTACK !! 355 if (err)
83 sp = current->sas_ss_sp + curr !! 356 return err;
84 !! 357
85 #ifdef CONFIG_ARCH_HAS_SC_SIGNALS !! 358 /* "Return" to the handler */
86 if (!(ksig->ka.sa.sa_flags & SA_SIGINF !! 359 regs->r26 = r26;
87 err = setup_signal_stack_sc(sp !! 360 regs->r27 = regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
88 else !! 361 regs->r16 = ksig->sig; /* a0: signal number */
>> 362 regs->r17 = 0; /* a1: exception code */
>> 363 regs->r18 = (unsigned long) &frame->sc; /* a2: sigcontext pointer */
>> 364 wrusp((unsigned long) frame);
>> 365
>> 366 #if DEBUG_SIG
>> 367 printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
>> 368 current->comm, current->pid, frame, regs->pc, regs->r26);
89 #endif 369 #endif
90 err = setup_signal_stack_si(sp !! 370 return 0;
91 <<
92 signal_setup_done(err, ksig, singleste <<
93 } 371 }
94 372
95 void do_signal(struct pt_regs *regs) !! 373 static int
>> 374 setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
96 { 375 {
97 struct ksignal ksig; !! 376 unsigned long oldsp, r26, err = 0;
98 int handled_sig = 0; !! 377 struct rt_sigframe __user *frame;
99 378
100 while (get_signal(&ksig)) { !! 379 oldsp = rdusp();
101 handled_sig = 1; !! 380 frame = get_sigframe(ksig, oldsp, sizeof(*frame));
102 /* Whee! Actually deliver the !! 381 if (!access_ok(frame, sizeof(*frame)))
103 handle_signal(&ksig, regs); !! 382 return -EFAULT;
>> 383
>> 384 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
>> 385
>> 386 /* Create the ucontext. */
>> 387 err |= __put_user(0, &frame->uc.uc_flags);
>> 388 err |= __put_user(0, &frame->uc.uc_link);
>> 389 err |= __put_user(set->sig[0], &frame->uc.uc_osf_sigmask);
>> 390 err |= __save_altstack(&frame->uc.uc_stack, oldsp);
>> 391 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs,
>> 392 set->sig[0], oldsp);
>> 393 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
>> 394 if (err)
>> 395 return -EFAULT;
>> 396
>> 397 /* Set up to return from userspace. If provided, use a stub
>> 398 already in userspace. */
>> 399 r26 = (unsigned long) ksig->ka.ka_restorer;
>> 400 if (!r26) {
>> 401 err |= __put_user(INSN_MOV_R30_R16, frame->retcode+0);
>> 402 err |= __put_user(INSN_LDI_R0+__NR_rt_sigreturn,
>> 403 frame->retcode+1);
>> 404 err |= __put_user(INSN_CALLSYS, frame->retcode+2);
>> 405 imb();
>> 406 r26 = (unsigned long) frame->retcode;
104 } 407 }
105 408
106 /* Did we come from a system call? */ !! 409 if (err)
107 if (!handled_sig && (PT_REGS_SYSCALL_N !! 410 return -EFAULT;
108 /* Restart the system call - n !! 411
109 switch (PT_REGS_SYSCALL_RET(re !! 412 /* "Return" to the handler */
110 case -ERESTARTNOHAND: !! 413 regs->r26 = r26;
111 case -ERESTARTSYS: !! 414 regs->r27 = regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
112 case -ERESTARTNOINTR: !! 415 regs->r16 = ksig->sig; /* a0: signal number */
113 PT_REGS_ORIG_SYSCALL(r !! 416 regs->r17 = (unsigned long) &frame->info; /* a1: siginfo pointer */
114 PT_REGS_RESTART_SYSCAL !! 417 regs->r18 = (unsigned long) &frame->uc; /* a2: ucontext pointer */
115 break; !! 418 wrusp((unsigned long) frame);
116 case -ERESTART_RESTARTBLOCK: !! 419
117 PT_REGS_ORIG_SYSCALL(r !! 420 #if DEBUG_SIG
118 PT_REGS_RESTART_SYSCAL !! 421 printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
>> 422 current->comm, current->pid, frame, regs->pc, regs->r26);
>> 423 #endif
>> 424
>> 425 return 0;
>> 426 }
>> 427
>> 428
>> 429 /*
>> 430 * OK, we're invoking a handler.
>> 431 */
>> 432 static inline void
>> 433 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
>> 434 {
>> 435 sigset_t *oldset = sigmask_to_save();
>> 436 int ret;
>> 437
>> 438 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
>> 439 ret = setup_rt_frame(ksig, oldset, regs);
>> 440 else
>> 441 ret = setup_frame(ksig, oldset, regs);
>> 442
>> 443 signal_setup_done(ret, ksig, 0);
>> 444 }
>> 445
>> 446 static inline void
>> 447 syscall_restart(unsigned long r0, unsigned long r19,
>> 448 struct pt_regs *regs, struct k_sigaction *ka)
>> 449 {
>> 450 switch (regs->r0) {
>> 451 case ERESTARTSYS:
>> 452 if (!(ka->sa.sa_flags & SA_RESTART)) {
>> 453 case ERESTARTNOHAND:
>> 454 regs->r0 = EINTR;
119 break; 455 break;
120 } 456 }
>> 457 fallthrough;
>> 458 case ERESTARTNOINTR:
>> 459 regs->r0 = r0; /* reset v0 and a3 and replay syscall */
>> 460 regs->r19 = r19;
>> 461 regs->pc -= 4;
>> 462 break;
>> 463 case ERESTART_RESTARTBLOCK:
>> 464 regs->r0 = EINTR;
>> 465 break;
121 } 466 }
>> 467 }
>> 468
>> 469
>> 470 /*
>> 471 * Note that 'init' is a special process: it doesn't get signals it doesn't
>> 472 * want to handle. Thus you cannot kill init even with a SIGKILL even by
>> 473 * mistake.
>> 474 *
>> 475 * Note that we go through the signals twice: once to check the signals that
>> 476 * the kernel can handle, and then we build all the user-level signal handling
>> 477 * stack-frames in one go after that.
>> 478 *
>> 479 * "r0" and "r19" are the registers we need to restore for system call
>> 480 * restart. "r0" is also used as an indicator whether we can restart at
>> 481 * all (if we get here from anything but a syscall return, it will be 0)
>> 482 */
>> 483 static void
>> 484 do_signal(struct pt_regs *regs, unsigned long r0, unsigned long r19)
>> 485 {
>> 486 unsigned long single_stepping = ptrace_cancel_bpt(current);
>> 487 struct ksignal ksig;
122 488
123 /* !! 489 /* This lets the debugger run, ... */
124 * if there's no signal to deliver, we !! 490 if (get_signal(&ksig)) {
125 * back !! 491 /* ... so re-check the single stepping. */
126 */ !! 492 single_stepping |= ptrace_cancel_bpt(current);
127 if (!handled_sig) !! 493 /* Whee! Actually deliver the signal. */
>> 494 if (r0)
>> 495 syscall_restart(r0, r19, regs, &ksig.ka);
>> 496 handle_signal(&ksig, regs);
>> 497 } else {
>> 498 single_stepping |= ptrace_cancel_bpt(current);
>> 499 if (r0) {
>> 500 switch (regs->r0) {
>> 501 case ERESTARTNOHAND:
>> 502 case ERESTARTSYS:
>> 503 case ERESTARTNOINTR:
>> 504 /* Reset v0 and a3 and replay syscall. */
>> 505 regs->r0 = r0;
>> 506 regs->r19 = r19;
>> 507 regs->pc -= 4;
>> 508 break;
>> 509 case ERESTART_RESTARTBLOCK:
>> 510 /* Set v0 to the restart_syscall and replay */
>> 511 regs->r0 = __NR_restart_syscall;
>> 512 regs->pc -= 4;
>> 513 break;
>> 514 }
>> 515 }
128 restore_saved_sigmask(); 516 restore_saved_sigmask();
>> 517 }
>> 518 if (single_stepping)
>> 519 ptrace_set_bpt(current); /* re-set breakpoint */
>> 520 }
>> 521
>> 522 void
>> 523 do_work_pending(struct pt_regs *regs, unsigned long thread_flags,
>> 524 unsigned long r0, unsigned long r19)
>> 525 {
>> 526 do {
>> 527 if (thread_flags & _TIF_NEED_RESCHED) {
>> 528 schedule();
>> 529 } else {
>> 530 local_irq_enable();
>> 531 if (thread_flags & (_TIF_SIGPENDING|_TIF_NOTIFY_SIGNAL)) {
>> 532 preempt_disable();
>> 533 save_fpu();
>> 534 preempt_enable();
>> 535 do_signal(regs, r0, r19);
>> 536 r0 = 0;
>> 537 } else {
>> 538 resume_user_mode_work(regs);
>> 539 }
>> 540 }
>> 541 local_irq_disable();
>> 542 thread_flags = read_thread_flags();
>> 543 } while (thread_flags & _TIF_WORK_MASK);
129 } 544 }
130 545
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