1 /* 2 * Signal support for Hexagon processor 3 * 4 * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 and 8 * only version 2 as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 18 * 02110-1301, USA. 19 */ 20 21 #include <linux/linkage.h> 22 #include <linux/syscalls.h> 23 #include <linux/freezer.h> 24 #include <linux/tracehook.h> 25 #include <asm/registers.h> 26 #include <asm/thread_info.h> 27 #include <asm/unistd.h> 28 #include <asm/uaccess.h> 29 #include <asm/ucontext.h> 30 #include <asm/cacheflush.h> 31 #include <asm/signal.h> 32 #include <asm/vdso.h> 33 34 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) 35 36 struct rt_sigframe { 37 unsigned long tramp[2]; 38 struct siginfo info; 39 struct ucontext uc; 40 }; 41 42 static void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, 43 size_t frame_size) 44 { 45 unsigned long sp = regs->r29; 46 47 /* Switch to signal stack if appropriate */ 48 if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0)) 49 sp = current->sas_ss_sp + current->sas_ss_size; 50 51 return (void __user *)((sp - frame_size) & ~(sizeof(long long) - 1)); 52 } 53 54 static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) 55 { 56 unsigned long tmp; 57 int err = 0; 58 59 err |= copy_to_user(&sc->sc_regs.r0, ®s->r00, 60 32*sizeof(unsigned long)); 61 62 err |= __put_user(regs->sa0, &sc->sc_regs.sa0); 63 err |= __put_user(regs->lc0, &sc->sc_regs.lc0); 64 err |= __put_user(regs->sa1, &sc->sc_regs.sa1); 65 err |= __put_user(regs->lc1, &sc->sc_regs.lc1); 66 err |= __put_user(regs->m0, &sc->sc_regs.m0); 67 err |= __put_user(regs->m1, &sc->sc_regs.m1); 68 err |= __put_user(regs->usr, &sc->sc_regs.usr); 69 err |= __put_user(regs->preds, &sc->sc_regs.p3_0); 70 err |= __put_user(regs->gp, &sc->sc_regs.gp); 71 err |= __put_user(regs->ugp, &sc->sc_regs.ugp); 72 73 tmp = pt_elr(regs); err |= __put_user(tmp, &sc->sc_regs.pc); 74 tmp = pt_cause(regs); err |= __put_user(tmp, &sc->sc_regs.cause); 75 tmp = pt_badva(regs); err |= __put_user(tmp, &sc->sc_regs.badva); 76 77 return err; 78 } 79 80 static int restore_sigcontext(struct pt_regs *regs, 81 struct sigcontext __user *sc) 82 { 83 unsigned long tmp; 84 int err = 0; 85 86 err |= copy_from_user(®s->r00, &sc->sc_regs.r0, 87 32 * sizeof(unsigned long)); 88 89 err |= __get_user(regs->sa0, &sc->sc_regs.sa0); 90 err |= __get_user(regs->lc0, &sc->sc_regs.lc0); 91 err |= __get_user(regs->sa1, &sc->sc_regs.sa1); 92 err |= __get_user(regs->lc1, &sc->sc_regs.lc1); 93 err |= __get_user(regs->m0, &sc->sc_regs.m0); 94 err |= __get_user(regs->m1, &sc->sc_regs.m1); 95 err |= __get_user(regs->usr, &sc->sc_regs.usr); 96 err |= __get_user(regs->preds, &sc->sc_regs.p3_0); 97 err |= __get_user(regs->gp, &sc->sc_regs.gp); 98 err |= __get_user(regs->ugp, &sc->sc_regs.ugp); 99 100 err |= __get_user(tmp, &sc->sc_regs.pc); pt_set_elr(regs, tmp); 101 102 return err; 103 } 104 105 /* 106 * Setup signal stack frame with siginfo structure 107 */ 108 static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info, 109 sigset_t *set, struct pt_regs *regs) 110 { 111 int err = 0; 112 struct rt_sigframe __user *frame; 113 struct hexagon_vdso *vdso = current->mm->context.vdso; 114 115 frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe)); 116 117 if (!access_ok(VERIFY_WRITE, frame, sizeof(struct rt_sigframe))) 118 goto sigsegv; 119 120 if (copy_siginfo_to_user(&frame->info, info)) 121 goto sigsegv; 122 123 /* The on-stack signal trampoline is no longer executed; 124 * however, the libgcc signal frame unwinding code checks for 125 * the presence of these two numeric magic values. 126 */ 127 err |= __put_user(0x7800d166, &frame->tramp[0]); 128 err |= __put_user(0x5400c004, &frame->tramp[1]); 129 err |= setup_sigcontext(regs, &frame->uc.uc_mcontext); 130 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 131 if (err) 132 goto sigsegv; 133 134 /* Load r0/r1 pair with signumber/siginfo pointer... */ 135 regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32) 136 | (unsigned long long)signr; 137 regs->r02 = (unsigned long) &frame->uc; 138 regs->r31 = (unsigned long) vdso->rt_signal_trampoline; 139 pt_psp(regs) = (unsigned long) frame; 140 pt_set_elr(regs, (unsigned long)ka->sa.sa_handler); 141 142 return 0; 143 144 sigsegv: 145 force_sigsegv(signr, current); 146 return -EFAULT; 147 } 148 149 /* 150 * Setup invocation of signal handler 151 */ 152 static int handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka, 153 sigset_t *oldset, struct pt_regs *regs) 154 { 155 int rc; 156 157 /* 158 * If we're handling a signal that aborted a system call, 159 * set up the error return value before adding the signal 160 * frame to the stack. 161 */ 162 163 if (regs->syscall_nr >= 0) { 164 switch (regs->r00) { 165 case -ERESTART_RESTARTBLOCK: 166 case -ERESTARTNOHAND: 167 regs->r00 = -EINTR; 168 break; 169 case -ERESTARTSYS: 170 if (!(ka->sa.sa_flags & SA_RESTART)) { 171 regs->r00 = -EINTR; 172 break; 173 } 174 /* Fall through */ 175 case -ERESTARTNOINTR: 176 regs->r06 = regs->syscall_nr; 177 pt_set_elr(regs, pt_elr(regs) - 4); 178 regs->r00 = regs->restart_r0; 179 break; 180 default: 181 break; 182 } 183 } 184 185 /* 186 * Set up the stack frame; not doing the SA_SIGINFO thing. We 187 * only set up the rt_frame flavor. 188 */ 189 rc = setup_rt_frame(sig, ka, info, oldset, regs); 190 191 /* If there was an error on setup, no signal was delivered. */ 192 if (rc) 193 return rc; 194 195 spin_lock_irq(¤t->sighand->siglock); 196 sigorsets(¤t->blocked, ¤t->blocked, &ka->sa.sa_mask); 197 if (!(ka->sa.sa_flags & SA_NODEFER)) 198 sigaddset(¤t->blocked, sig); 199 recalc_sigpending(); 200 spin_unlock_irq(¤t->sighand->siglock); 201 202 return 0; 203 } 204 205 /* 206 * Called from return-from-event code. 207 */ 208 static void do_signal(struct pt_regs *regs) 209 { 210 struct k_sigaction sigact; 211 siginfo_t info; 212 int signo; 213 214 if (!user_mode(regs)) 215 return; 216 217 if (try_to_freeze()) 218 goto no_signal; 219 220 signo = get_signal_to_deliver(&info, &sigact, regs, NULL); 221 222 if (signo > 0) { 223 sigset_t *oldset; 224 225 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 226 oldset = ¤t->saved_sigmask; 227 else 228 oldset = ¤t->blocked; 229 230 if (handle_signal(signo, &info, &sigact, oldset, regs) == 0) { 231 /* 232 * Successful delivery case. The saved sigmask is 233 * stored in the signal frame, and will be restored 234 * by sigreturn. We can clear the TIF flag. 235 */ 236 clear_thread_flag(TIF_RESTORE_SIGMASK); 237 238 tracehook_signal_handler(signo, &info, &sigact, regs, 239 test_thread_flag(TIF_SINGLESTEP)); 240 } 241 return; 242 } 243 244 no_signal: 245 /* 246 * If we came from a system call, handle the restart. 247 */ 248 if (regs->syscall_nr >= 0) { 249 switch (regs->r00) { 250 case -ERESTARTNOHAND: 251 case -ERESTARTSYS: 252 case -ERESTARTNOINTR: 253 regs->r06 = regs->syscall_nr; 254 break; 255 case -ERESTART_RESTARTBLOCK: 256 regs->r06 = __NR_restart_syscall; 257 break; 258 default: 259 goto no_restart; 260 } 261 pt_set_elr(regs, pt_elr(regs) - 4); 262 regs->r00 = regs->restart_r0; 263 } 264 265 no_restart: 266 /* If there's no signal to deliver, put the saved sigmask back */ 267 if (test_thread_flag(TIF_RESTORE_SIGMASK)) { 268 clear_thread_flag(TIF_RESTORE_SIGMASK); 269 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); 270 } 271 } 272 273 void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags) 274 { 275 if (thread_info_flags & _TIF_SIGPENDING) 276 do_signal(regs); 277 278 if (thread_info_flags & _TIF_NOTIFY_RESUME) { 279 clear_thread_flag(TIF_NOTIFY_RESUME); 280 if (current->replacement_session_keyring) 281 key_replace_session_keyring(); 282 } 283 } 284 285 /* 286 * Architecture-specific wrappers for signal-related system calls 287 */ 288 asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss) 289 { 290 struct pt_regs *regs = current_thread_info()->regs; 291 292 return do_sigaltstack(uss, uoss, regs->r29); 293 } 294 295 asmlinkage int sys_rt_sigreturn(void) 296 { 297 struct pt_regs *regs = current_thread_info()->regs; 298 struct rt_sigframe __user *frame; 299 sigset_t blocked; 300 301 frame = (struct rt_sigframe __user *)pt_psp(regs); 302 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 303 goto badframe; 304 if (__copy_from_user(&blocked, &frame->uc.uc_sigmask, sizeof(blocked))) 305 goto badframe; 306 307 sigdelsetmask(&blocked, ~_BLOCKABLE); 308 spin_lock_irq(¤t->sighand->siglock); 309 current->blocked = blocked; 310 recalc_sigpending(); 311 spin_unlock_irq(¤t->sighand->siglock); 312 313 if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) 314 goto badframe; 315 316 /* Restore the user's stack as well */ 317 pt_psp(regs) = regs->r29; 318 319 /* 320 * Leave a trace in the stack frame that this was a sigreturn. 321 * If the system call is to replay, we've already restored the 322 * number in the GPR slot and it will be regenerated on the 323 * new system call trap entry. Note that if restore_sigcontext() 324 * did something other than a bulk copy of the pt_regs struct, 325 * we could avoid this assignment by simply not overwriting 326 * regs->syscall_nr. 327 */ 328 regs->syscall_nr = __NR_rt_sigreturn; 329 330 /* 331 * If we were meticulous, we'd only call this if we knew that 332 * we were actually going to use an alternate stack, and we'd 333 * consider any error to be fatal. What we do here, in common 334 * with many other architectures, is call it blindly and only 335 * consider the -EFAULT return case to be proof of a problem. 336 */ 337 if (do_sigaltstack(&frame->uc.uc_stack, NULL, pt_psp(regs)) == -EFAULT) 338 goto badframe; 339 340 return 0; 341 342 badframe: 343 force_sig(SIGSEGV, current); 344 return 0; 345 } 346