1 /* 2 * Signal handling 3 * 4 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu> 5 * Copyright (C) 2008-2009 PetaLogix 6 * Copyright (C) 2003,2004 John Williams <jwilliams@itee.uq.edu.au> 7 * Copyright (C) 2001 NEC Corporation 8 * Copyright (C) 2001 Miles Bader <miles@gnu.org> 9 * Copyright (C) 1999,2000 Niibe Yutaka & Kaz Kojima 10 * Copyright (C) 1991,1992 Linus Torvalds 11 * 12 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson 13 * 14 * This file was was derived from the sh version, arch/sh/kernel/signal.c 15 * 16 * This file is subject to the terms and conditions of the GNU General 17 * Public License. See the file COPYING in the main directory of this 18 * archive for more details. 19 */ 20 21 #include <linux/sched.h> 22 #include <linux/mm.h> 23 #include <linux/smp.h> 24 #include <linux/kernel.h> 25 #include <linux/signal.h> 26 #include <linux/errno.h> 27 #include <linux/wait.h> 28 #include <linux/ptrace.h> 29 #include <linux/unistd.h> 30 #include <linux/stddef.h> 31 #include <linux/personality.h> 32 #include <linux/percpu.h> 33 #include <linux/linkage.h> 34 #include <linux/tracehook.h> 35 #include <asm/entry.h> 36 #include <asm/ucontext.h> 37 #include <linux/uaccess.h> 38 #include <asm/pgtable.h> 39 #include <asm/pgalloc.h> 40 #include <linux/syscalls.h> 41 #include <asm/cacheflush.h> 42 #include <asm/syscalls.h> 43 44 asmlinkage long 45 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, 46 struct pt_regs *regs) 47 { 48 return do_sigaltstack(uss, uoss, regs->r1); 49 } 50 51 /* 52 * Do a signal return; undo the signal stack. 53 */ 54 struct sigframe { 55 struct sigcontext sc; 56 unsigned long extramask[_NSIG_WORDS-1]; 57 unsigned long tramp[2]; /* signal trampoline */ 58 }; 59 60 struct rt_sigframe { 61 struct siginfo info; 62 struct ucontext uc; 63 unsigned long tramp[2]; /* signal trampoline */ 64 }; 65 66 static int restore_sigcontext(struct pt_regs *regs, 67 struct sigcontext __user *sc, int *rval_p) 68 { 69 unsigned int err = 0; 70 71 #define COPY(x) {err |= __get_user(regs->x, &sc->regs.x); } 72 COPY(r0); 73 COPY(r1); 74 COPY(r2); COPY(r3); COPY(r4); COPY(r5); 75 COPY(r6); COPY(r7); COPY(r8); COPY(r9); 76 COPY(r10); COPY(r11); COPY(r12); COPY(r13); 77 COPY(r14); COPY(r15); COPY(r16); COPY(r17); 78 COPY(r18); COPY(r19); COPY(r20); COPY(r21); 79 COPY(r22); COPY(r23); COPY(r24); COPY(r25); 80 COPY(r26); COPY(r27); COPY(r28); COPY(r29); 81 COPY(r30); COPY(r31); 82 COPY(pc); COPY(ear); COPY(esr); COPY(fsr); 83 #undef COPY 84 85 *rval_p = regs->r3; 86 87 return err; 88 } 89 90 asmlinkage long sys_rt_sigreturn(struct pt_regs *regs) 91 { 92 struct rt_sigframe __user *frame = 93 (struct rt_sigframe __user *)(regs->r1); 94 95 sigset_t set; 96 int rval; 97 98 /* Always make any pending restarted system calls return -EINTR */ 99 current_thread_info()->restart_block.fn = do_no_restart_syscall; 100 101 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 102 goto badframe; 103 104 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 105 goto badframe; 106 107 set_current_blocked(&set); 108 109 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &rval)) 110 goto badframe; 111 112 /* It is more difficult to avoid calling this function than to 113 call it and ignore errors. */ 114 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->r1) == -EFAULT) 115 goto badframe; 116 117 return rval; 118 119 badframe: 120 force_sig(SIGSEGV, current); 121 return 0; 122 } 123 124 /* 125 * Set up a signal frame. 126 */ 127 128 static int 129 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, 130 unsigned long mask) 131 { 132 int err = 0; 133 134 #define COPY(x) {err |= __put_user(regs->x, &sc->regs.x); } 135 COPY(r0); 136 COPY(r1); 137 COPY(r2); COPY(r3); COPY(r4); COPY(r5); 138 COPY(r6); COPY(r7); COPY(r8); COPY(r9); 139 COPY(r10); COPY(r11); COPY(r12); COPY(r13); 140 COPY(r14); COPY(r15); COPY(r16); COPY(r17); 141 COPY(r18); COPY(r19); COPY(r20); COPY(r21); 142 COPY(r22); COPY(r23); COPY(r24); COPY(r25); 143 COPY(r26); COPY(r27); COPY(r28); COPY(r29); 144 COPY(r30); COPY(r31); 145 COPY(pc); COPY(ear); COPY(esr); COPY(fsr); 146 #undef COPY 147 148 err |= __put_user(mask, &sc->oldmask); 149 150 return err; 151 } 152 153 /* 154 * Determine which stack to use.. 155 */ 156 static inline void __user * 157 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size) 158 { 159 /* Default to using normal stack */ 160 unsigned long sp = regs->r1; 161 162 if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && !on_sig_stack(sp)) 163 sp = current->sas_ss_sp + current->sas_ss_size; 164 165 return (void __user *)((sp - frame_size) & -8UL); 166 } 167 168 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, 169 sigset_t *set, struct pt_regs *regs) 170 { 171 struct rt_sigframe __user *frame; 172 int err = 0; 173 int signal; 174 unsigned long address = 0; 175 #ifdef CONFIG_MMU 176 pmd_t *pmdp; 177 pte_t *ptep; 178 #endif 179 180 frame = get_sigframe(ka, regs, sizeof(*frame)); 181 182 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 183 goto give_sigsegv; 184 185 signal = current_thread_info()->exec_domain 186 && current_thread_info()->exec_domain->signal_invmap 187 && sig < 32 188 ? current_thread_info()->exec_domain->signal_invmap[sig] 189 : sig; 190 191 if (info) 192 err |= copy_siginfo_to_user(&frame->info, info); 193 194 /* Create the ucontext. */ 195 err |= __put_user(0, &frame->uc.uc_flags); 196 err |= __put_user(NULL, &frame->uc.uc_link); 197 err |= __put_user((void __user *)current->sas_ss_sp, 198 &frame->uc.uc_stack.ss_sp); 199 err |= __put_user(sas_ss_flags(regs->r1), 200 &frame->uc.uc_stack.ss_flags); 201 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); 202 err |= setup_sigcontext(&frame->uc.uc_mcontext, 203 regs, set->sig[0]); 204 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 205 206 /* Set up to return from userspace. If provided, use a stub 207 already in userspace. */ 208 /* minus 8 is offset to cater for "rtsd r15,8" */ 209 /* addi r12, r0, __NR_sigreturn */ 210 err |= __put_user(0x31800000 | __NR_rt_sigreturn , 211 frame->tramp + 0); 212 /* brki r14, 0x8 */ 213 err |= __put_user(0xb9cc0008, frame->tramp + 1); 214 215 /* Return from sighandler will jump to the tramp. 216 Negative 8 offset because return is rtsd r15, 8 */ 217 regs->r15 = ((unsigned long)frame->tramp)-8; 218 219 address = ((unsigned long)frame->tramp); 220 #ifdef CONFIG_MMU 221 pmdp = pmd_offset(pud_offset( 222 pgd_offset(current->mm, address), 223 address), address); 224 225 preempt_disable(); 226 ptep = pte_offset_map(pmdp, address); 227 if (pte_present(*ptep)) { 228 address = (unsigned long) page_address(pte_page(*ptep)); 229 /* MS: I need add offset in page */ 230 address += ((unsigned long)frame->tramp) & ~PAGE_MASK; 231 /* MS address is virtual */ 232 address = virt_to_phys(address); 233 invalidate_icache_range(address, address + 8); 234 flush_dcache_range(address, address + 8); 235 } 236 pte_unmap(ptep); 237 preempt_enable(); 238 #else 239 flush_icache_range(address, address + 8); 240 flush_dcache_range(address, address + 8); 241 #endif 242 if (err) 243 goto give_sigsegv; 244 245 /* Set up registers for signal handler */ 246 regs->r1 = (unsigned long) frame; 247 248 /* Signal handler args: */ 249 regs->r5 = signal; /* arg 0: signum */ 250 regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */ 251 regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */ 252 /* Offset to handle microblaze rtid r14, 0 */ 253 regs->pc = (unsigned long)ka->sa.sa_handler; 254 255 set_fs(USER_DS); 256 257 #ifdef DEBUG_SIG 258 printk(KERN_INFO "SIG deliver (%s:%d): sp=%p pc=%08lx\n", 259 current->comm, current->pid, frame, regs->pc); 260 #endif 261 262 return 0; 263 264 give_sigsegv: 265 force_sigsegv(sig, current); 266 return -EFAULT; 267 } 268 269 /* Handle restarting system calls */ 270 static inline void 271 handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler) 272 { 273 switch (regs->r3) { 274 case -ERESTART_RESTARTBLOCK: 275 case -ERESTARTNOHAND: 276 if (!has_handler) 277 goto do_restart; 278 regs->r3 = -EINTR; 279 break; 280 case -ERESTARTSYS: 281 if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) { 282 regs->r3 = -EINTR; 283 break; 284 } 285 /* fallthrough */ 286 case -ERESTARTNOINTR: 287 do_restart: 288 /* offset of 4 bytes to re-execute trap (brki) instruction */ 289 regs->pc -= 4; 290 break; 291 } 292 } 293 294 /* 295 * OK, we're invoking a handler 296 */ 297 298 static void 299 handle_signal(unsigned long sig, struct k_sigaction *ka, 300 siginfo_t *info, struct pt_regs *regs) 301 { 302 sigset_t *oldset = sigmask_to_save(); 303 int ret; 304 305 /* Set up the stack frame */ 306 if (ka->sa.sa_flags & SA_SIGINFO) 307 ret = setup_rt_frame(sig, ka, info, oldset, regs); 308 else 309 ret = setup_rt_frame(sig, ka, NULL, oldset, regs); 310 311 if (ret) 312 return; 313 314 signal_delivered(sig, info, ka, regs, 315 test_thread_flag(TIF_SINGLESTEP)); 316 } 317 318 /* 319 * Note that 'init' is a special process: it doesn't get signals it doesn't 320 * want to handle. Thus you cannot kill init even with a SIGKILL even by 321 * mistake. 322 * 323 * Note that we go through the signals twice: once to check the signals that 324 * the kernel can handle, and then we build all the user-level signal handling 325 * stack-frames in one go after that. 326 */ 327 static void do_signal(struct pt_regs *regs, int in_syscall) 328 { 329 siginfo_t info; 330 int signr; 331 struct k_sigaction ka; 332 #ifdef DEBUG_SIG 333 printk(KERN_INFO "do signal: %p %d\n", regs, in_syscall); 334 printk(KERN_INFO "do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1, 335 regs->r12, current_thread_info()->flags); 336 #endif 337 338 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 339 if (signr > 0) { 340 /* Whee! Actually deliver the signal. */ 341 if (in_syscall) 342 handle_restart(regs, &ka, 1); 343 handle_signal(signr, &ka, &info, regs); 344 return; 345 } 346 347 if (in_syscall) 348 handle_restart(regs, NULL, 0); 349 350 /* 351 * If there's no signal to deliver, we just put the saved sigmask 352 * back. 353 */ 354 restore_saved_sigmask(); 355 } 356 357 void do_notify_resume(struct pt_regs *regs, int in_syscall) 358 { 359 /* 360 * We want the common case to go fast, which 361 * is why we may in certain cases get here from 362 * kernel mode. Just return without doing anything 363 * if so. 364 */ 365 if (kernel_mode(regs)) 366 return; 367 368 if (test_thread_flag(TIF_SIGPENDING)) 369 do_signal(regs, in_syscall); 370 371 if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) 372 tracehook_notify_resume(regs); 373 } 374