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/pgalloc.h> 39 #include <linux/syscalls.h> 40 #include <asm/cacheflush.h> 41 #include <asm/syscalls.h> 42 43 /* 44 * Do a signal return; undo the signal stack. 45 */ 46 struct sigframe { 47 struct sigcontext sc; 48 unsigned long extramask[_NSIG_WORDS-1]; 49 unsigned long tramp[2]; /* signal trampoline */ 50 }; 51 52 struct rt_sigframe { 53 struct siginfo info; 54 struct ucontext uc; 55 unsigned long tramp[2]; /* signal trampoline */ 56 }; 57 58 static int restore_sigcontext(struct pt_regs *regs, 59 struct sigcontext __user *sc, int *rval_p) 60 { 61 unsigned int err = 0; 62 63 #define COPY(x) {err |= __get_user(regs->x, &sc->regs.x); } 64 COPY(r0); 65 COPY(r1); 66 COPY(r2); COPY(r3); COPY(r4); COPY(r5); 67 COPY(r6); COPY(r7); COPY(r8); COPY(r9); 68 COPY(r10); COPY(r11); COPY(r12); COPY(r13); 69 COPY(r14); COPY(r15); COPY(r16); COPY(r17); 70 COPY(r18); COPY(r19); COPY(r20); COPY(r21); 71 COPY(r22); COPY(r23); COPY(r24); COPY(r25); 72 COPY(r26); COPY(r27); COPY(r28); COPY(r29); 73 COPY(r30); COPY(r31); 74 COPY(pc); COPY(ear); COPY(esr); COPY(fsr); 75 #undef COPY 76 77 *rval_p = regs->r3; 78 79 return err; 80 } 81 82 asmlinkage long sys_rt_sigreturn(struct pt_regs *regs) 83 { 84 struct rt_sigframe __user *frame = 85 (struct rt_sigframe __user *)(regs->r1); 86 87 sigset_t set; 88 int rval; 89 90 /* Always make any pending restarted system calls return -EINTR */ 91 current->restart_block.fn = do_no_restart_syscall; 92 93 if (!access_ok(frame, sizeof(*frame))) 94 goto badframe; 95 96 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 97 goto badframe; 98 99 set_current_blocked(&set); 100 101 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &rval)) 102 goto badframe; 103 104 if (restore_altstack(&frame->uc.uc_stack)) 105 goto badframe; 106 107 return rval; 108 109 badframe: 110 force_sig(SIGSEGV); 111 return 0; 112 } 113 114 /* 115 * Set up a signal frame. 116 */ 117 118 static int 119 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, 120 unsigned long mask) 121 { 122 int err = 0; 123 124 #define COPY(x) {err |= __put_user(regs->x, &sc->regs.x); } 125 COPY(r0); 126 COPY(r1); 127 COPY(r2); COPY(r3); COPY(r4); COPY(r5); 128 COPY(r6); COPY(r7); COPY(r8); COPY(r9); 129 COPY(r10); COPY(r11); COPY(r12); COPY(r13); 130 COPY(r14); COPY(r15); COPY(r16); COPY(r17); 131 COPY(r18); COPY(r19); COPY(r20); COPY(r21); 132 COPY(r22); COPY(r23); COPY(r24); COPY(r25); 133 COPY(r26); COPY(r27); COPY(r28); COPY(r29); 134 COPY(r30); COPY(r31); 135 COPY(pc); COPY(ear); COPY(esr); COPY(fsr); 136 #undef COPY 137 138 err |= __put_user(mask, &sc->oldmask); 139 140 return err; 141 } 142 143 /* 144 * Determine which stack to use.. 145 */ 146 static inline void __user * 147 get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size) 148 { 149 /* Default to using normal stack */ 150 unsigned long sp = sigsp(regs->r1, ksig); 151 152 return (void __user *)((sp - frame_size) & -8UL); 153 } 154 155 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, 156 struct pt_regs *regs) 157 { 158 struct rt_sigframe __user *frame; 159 int err = 0, sig = ksig->sig; 160 unsigned long address = 0; 161 #ifdef CONFIG_MMU 162 pmd_t *pmdp; 163 pte_t *ptep; 164 #endif 165 166 frame = get_sigframe(ksig, regs, sizeof(*frame)); 167 168 if (!access_ok(frame, sizeof(*frame))) 169 return -EFAULT; 170 171 if (ksig->ka.sa.sa_flags & SA_SIGINFO) 172 err |= copy_siginfo_to_user(&frame->info, &ksig->info); 173 174 /* Create the ucontext. */ 175 err |= __put_user(0, &frame->uc.uc_flags); 176 err |= __put_user(NULL, &frame->uc.uc_link); 177 err |= __save_altstack(&frame->uc.uc_stack, regs->r1); 178 err |= setup_sigcontext(&frame->uc.uc_mcontext, 179 regs, set->sig[0]); 180 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 181 182 /* Set up to return from userspace. If provided, use a stub 183 already in userspace. */ 184 /* minus 8 is offset to cater for "rtsd r15,8" */ 185 /* addi r12, r0, __NR_sigreturn */ 186 err |= __put_user(0x31800000 | __NR_rt_sigreturn , 187 frame->tramp + 0); 188 /* brki r14, 0x8 */ 189 err |= __put_user(0xb9cc0008, frame->tramp + 1); 190 191 /* Return from sighandler will jump to the tramp. 192 Negative 8 offset because return is rtsd r15, 8 */ 193 regs->r15 = ((unsigned long)frame->tramp)-8; 194 195 address = ((unsigned long)frame->tramp); 196 #ifdef CONFIG_MMU 197 pmdp = pmd_off(current->mm, address); 198 199 preempt_disable(); 200 ptep = pte_offset_map(pmdp, address); 201 if (pte_present(*ptep)) { 202 address = (unsigned long) page_address(pte_page(*ptep)); 203 /* MS: I need add offset in page */ 204 address += ((unsigned long)frame->tramp) & ~PAGE_MASK; 205 /* MS address is virtual */ 206 address = __virt_to_phys(address); 207 invalidate_icache_range(address, address + 8); 208 flush_dcache_range(address, address + 8); 209 } 210 pte_unmap(ptep); 211 preempt_enable(); 212 #else 213 flush_icache_range(address, address + 8); 214 flush_dcache_range(address, address + 8); 215 #endif 216 if (err) 217 return -EFAULT; 218 219 /* Set up registers for signal handler */ 220 regs->r1 = (unsigned long) frame; 221 222 /* Signal handler args: */ 223 regs->r5 = sig; /* arg 0: signum */ 224 regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */ 225 regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */ 226 /* Offset to handle microblaze rtid r14, 0 */ 227 regs->pc = (unsigned long)ksig->ka.sa.sa_handler; 228 229 #ifdef DEBUG_SIG 230 pr_info("SIG deliver (%s:%d): sp=%p pc=%08lx\n", 231 current->comm, current->pid, frame, regs->pc); 232 #endif 233 234 return 0; 235 } 236 237 /* Handle restarting system calls */ 238 static inline void 239 handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler) 240 { 241 switch (regs->r3) { 242 case -ERESTART_RESTARTBLOCK: 243 case -ERESTARTNOHAND: 244 if (!has_handler) 245 goto do_restart; 246 regs->r3 = -EINTR; 247 break; 248 case -ERESTARTSYS: 249 if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) { 250 regs->r3 = -EINTR; 251 break; 252 } 253 /* fallthrough */ 254 case -ERESTARTNOINTR: 255 do_restart: 256 /* offset of 4 bytes to re-execute trap (brki) instruction */ 257 regs->pc -= 4; 258 break; 259 } 260 } 261 262 /* 263 * OK, we're invoking a handler 264 */ 265 266 static void 267 handle_signal(struct ksignal *ksig, struct pt_regs *regs) 268 { 269 sigset_t *oldset = sigmask_to_save(); 270 int ret; 271 272 /* Set up the stack frame */ 273 ret = setup_rt_frame(ksig, oldset, regs); 274 275 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); 276 } 277 278 /* 279 * Note that 'init' is a special process: it doesn't get signals it doesn't 280 * want to handle. Thus you cannot kill init even with a SIGKILL even by 281 * mistake. 282 * 283 * Note that we go through the signals twice: once to check the signals that 284 * the kernel can handle, and then we build all the user-level signal handling 285 * stack-frames in one go after that. 286 */ 287 static void do_signal(struct pt_regs *regs, int in_syscall) 288 { 289 struct ksignal ksig; 290 291 #ifdef DEBUG_SIG 292 pr_info("do signal: %p %d\n", regs, in_syscall); 293 pr_info("do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1, 294 regs->r12, current_thread_info()->flags); 295 #endif 296 297 if (get_signal(&ksig)) { 298 /* Whee! Actually deliver the signal. */ 299 if (in_syscall) 300 handle_restart(regs, &ksig.ka, 1); 301 handle_signal(&ksig, regs); 302 return; 303 } 304 305 if (in_syscall) 306 handle_restart(regs, NULL, 0); 307 308 /* 309 * If there's no signal to deliver, we just put the saved sigmask 310 * back. 311 */ 312 restore_saved_sigmask(); 313 } 314 315 asmlinkage void do_notify_resume(struct pt_regs *regs, int in_syscall) 316 { 317 if (test_thread_flag(TIF_SIGPENDING)) 318 do_signal(regs, in_syscall); 319 320 if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) 321 tracehook_notify_resume(regs); 322 } 323