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 /* 45 * Do a signal return; undo the signal stack. 46 */ 47 struct sigframe { 48 struct sigcontext sc; 49 unsigned long extramask[_NSIG_WORDS-1]; 50 unsigned long tramp[2]; /* signal trampoline */ 51 }; 52 53 struct rt_sigframe { 54 struct siginfo info; 55 struct ucontext uc; 56 unsigned long tramp[2]; /* signal trampoline */ 57 }; 58 59 static int restore_sigcontext(struct pt_regs *regs, 60 struct sigcontext __user *sc, int *rval_p) 61 { 62 unsigned int err = 0; 63 64 #define COPY(x) {err |= __get_user(regs->x, &sc->regs.x); } 65 COPY(r0); 66 COPY(r1); 67 COPY(r2); COPY(r3); COPY(r4); COPY(r5); 68 COPY(r6); COPY(r7); COPY(r8); COPY(r9); 69 COPY(r10); COPY(r11); COPY(r12); COPY(r13); 70 COPY(r14); COPY(r15); COPY(r16); COPY(r17); 71 COPY(r18); COPY(r19); COPY(r20); COPY(r21); 72 COPY(r22); COPY(r23); COPY(r24); COPY(r25); 73 COPY(r26); COPY(r27); COPY(r28); COPY(r29); 74 COPY(r30); COPY(r31); 75 COPY(pc); COPY(ear); COPY(esr); COPY(fsr); 76 #undef COPY 77 78 *rval_p = regs->r3; 79 80 return err; 81 } 82 83 asmlinkage long sys_rt_sigreturn(struct pt_regs *regs) 84 { 85 struct rt_sigframe __user *frame = 86 (struct rt_sigframe __user *)(regs->r1); 87 88 sigset_t set; 89 int rval; 90 91 /* Always make any pending restarted system calls return -EINTR */ 92 current_thread_info()->restart_block.fn = do_no_restart_syscall; 93 94 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 95 goto badframe; 96 97 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 98 goto badframe; 99 100 set_current_blocked(&set); 101 102 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &rval)) 103 goto badframe; 104 105 if (restore_altstack(&frame->uc.uc_stack)) 106 goto badframe; 107 108 return rval; 109 110 badframe: 111 force_sig(SIGSEGV, current); 112 return 0; 113 } 114 115 /* 116 * Set up a signal frame. 117 */ 118 119 static int 120 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, 121 unsigned long mask) 122 { 123 int err = 0; 124 125 #define COPY(x) {err |= __put_user(regs->x, &sc->regs.x); } 126 COPY(r0); 127 COPY(r1); 128 COPY(r2); COPY(r3); COPY(r4); COPY(r5); 129 COPY(r6); COPY(r7); COPY(r8); COPY(r9); 130 COPY(r10); COPY(r11); COPY(r12); COPY(r13); 131 COPY(r14); COPY(r15); COPY(r16); COPY(r17); 132 COPY(r18); COPY(r19); COPY(r20); COPY(r21); 133 COPY(r22); COPY(r23); COPY(r24); COPY(r25); 134 COPY(r26); COPY(r27); COPY(r28); COPY(r29); 135 COPY(r30); COPY(r31); 136 COPY(pc); COPY(ear); COPY(esr); COPY(fsr); 137 #undef COPY 138 139 err |= __put_user(mask, &sc->oldmask); 140 141 return err; 142 } 143 144 /* 145 * Determine which stack to use.. 146 */ 147 static inline void __user * 148 get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size) 149 { 150 /* Default to using normal stack */ 151 unsigned long sp = sigsp(regs->r1, ksig); 152 153 return (void __user *)((sp - frame_size) & -8UL); 154 } 155 156 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, 157 struct pt_regs *regs) 158 { 159 struct rt_sigframe __user *frame; 160 int err = 0, sig = ksig->sig; 161 int signal; 162 unsigned long address = 0; 163 #ifdef CONFIG_MMU 164 pmd_t *pmdp; 165 pte_t *ptep; 166 #endif 167 168 frame = get_sigframe(ksig, regs, sizeof(*frame)); 169 170 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 171 return -EFAULT; 172 173 signal = current_thread_info()->exec_domain 174 && current_thread_info()->exec_domain->signal_invmap 175 && sig < 32 176 ? current_thread_info()->exec_domain->signal_invmap[sig] 177 : sig; 178 179 if (ksig->ka.sa.sa_flags & SA_SIGINFO) 180 err |= copy_siginfo_to_user(&frame->info, &ksig->info); 181 182 /* Create the ucontext. */ 183 err |= __put_user(0, &frame->uc.uc_flags); 184 err |= __put_user(NULL, &frame->uc.uc_link); 185 err |= __save_altstack(&frame->uc.uc_stack, regs->r1); 186 err |= setup_sigcontext(&frame->uc.uc_mcontext, 187 regs, set->sig[0]); 188 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 189 190 /* Set up to return from userspace. If provided, use a stub 191 already in userspace. */ 192 /* minus 8 is offset to cater for "rtsd r15,8" */ 193 /* addi r12, r0, __NR_sigreturn */ 194 err |= __put_user(0x31800000 | __NR_rt_sigreturn , 195 frame->tramp + 0); 196 /* brki r14, 0x8 */ 197 err |= __put_user(0xb9cc0008, frame->tramp + 1); 198 199 /* Return from sighandler will jump to the tramp. 200 Negative 8 offset because return is rtsd r15, 8 */ 201 regs->r15 = ((unsigned long)frame->tramp)-8; 202 203 address = ((unsigned long)frame->tramp); 204 #ifdef CONFIG_MMU 205 pmdp = pmd_offset(pud_offset( 206 pgd_offset(current->mm, address), 207 address), address); 208 209 preempt_disable(); 210 ptep = pte_offset_map(pmdp, address); 211 if (pte_present(*ptep)) { 212 address = (unsigned long) page_address(pte_page(*ptep)); 213 /* MS: I need add offset in page */ 214 address += ((unsigned long)frame->tramp) & ~PAGE_MASK; 215 /* MS address is virtual */ 216 address = __virt_to_phys(address); 217 invalidate_icache_range(address, address + 8); 218 flush_dcache_range(address, address + 8); 219 } 220 pte_unmap(ptep); 221 preempt_enable(); 222 #else 223 flush_icache_range(address, address + 8); 224 flush_dcache_range(address, address + 8); 225 #endif 226 if (err) 227 return -EFAULT; 228 229 /* Set up registers for signal handler */ 230 regs->r1 = (unsigned long) frame; 231 232 /* Signal handler args: */ 233 regs->r5 = signal; /* arg 0: signum */ 234 regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */ 235 regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */ 236 /* Offset to handle microblaze rtid r14, 0 */ 237 regs->pc = (unsigned long)ksig->ka.sa.sa_handler; 238 239 set_fs(USER_DS); 240 241 #ifdef DEBUG_SIG 242 pr_info("SIG deliver (%s:%d): sp=%p pc=%08lx\n", 243 current->comm, current->pid, frame, regs->pc); 244 #endif 245 246 return 0; 247 } 248 249 /* Handle restarting system calls */ 250 static inline void 251 handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler) 252 { 253 switch (regs->r3) { 254 case -ERESTART_RESTARTBLOCK: 255 case -ERESTARTNOHAND: 256 if (!has_handler) 257 goto do_restart; 258 regs->r3 = -EINTR; 259 break; 260 case -ERESTARTSYS: 261 if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) { 262 regs->r3 = -EINTR; 263 break; 264 } 265 /* fallthrough */ 266 case -ERESTARTNOINTR: 267 do_restart: 268 /* offset of 4 bytes to re-execute trap (brki) instruction */ 269 regs->pc -= 4; 270 break; 271 } 272 } 273 274 /* 275 * OK, we're invoking a handler 276 */ 277 278 static void 279 handle_signal(struct ksignal *ksig, struct pt_regs *regs) 280 { 281 sigset_t *oldset = sigmask_to_save(); 282 int ret; 283 284 /* Set up the stack frame */ 285 ret = setup_rt_frame(ksig, oldset, regs); 286 287 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); 288 } 289 290 /* 291 * Note that 'init' is a special process: it doesn't get signals it doesn't 292 * want to handle. Thus you cannot kill init even with a SIGKILL even by 293 * mistake. 294 * 295 * Note that we go through the signals twice: once to check the signals that 296 * the kernel can handle, and then we build all the user-level signal handling 297 * stack-frames in one go after that. 298 */ 299 static void do_signal(struct pt_regs *regs, int in_syscall) 300 { 301 struct ksignal ksig; 302 303 #ifdef DEBUG_SIG 304 pr_info("do signal: %p %d\n", regs, in_syscall); 305 pr_info("do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1, 306 regs->r12, current_thread_info()->flags); 307 #endif 308 309 if (get_signal(&ksig)) { 310 /* Whee! Actually deliver the signal. */ 311 if (in_syscall) 312 handle_restart(regs, &ksig.ka, 1); 313 handle_signal(&ksig, regs); 314 return; 315 } 316 317 if (in_syscall) 318 handle_restart(regs, NULL, 0); 319 320 /* 321 * If there's no signal to deliver, we just put the saved sigmask 322 * back. 323 */ 324 restore_saved_sigmask(); 325 } 326 327 asmlinkage void do_notify_resume(struct pt_regs *regs, int in_syscall) 328 { 329 if (test_thread_flag(TIF_SIGPENDING)) 330 do_signal(regs, in_syscall); 331 332 if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) 333 tracehook_notify_resume(regs); 334 } 335