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->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 unsigned long address = 0; 162 #ifdef CONFIG_MMU 163 pmd_t *pmdp; 164 pte_t *ptep; 165 #endif 166 167 frame = get_sigframe(ksig, regs, sizeof(*frame)); 168 169 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 170 return -EFAULT; 171 172 if (ksig->ka.sa.sa_flags & SA_SIGINFO) 173 err |= copy_siginfo_to_user(&frame->info, &ksig->info); 174 175 /* Create the ucontext. */ 176 err |= __put_user(0, &frame->uc.uc_flags); 177 err |= __put_user(NULL, &frame->uc.uc_link); 178 err |= __save_altstack(&frame->uc.uc_stack, regs->r1); 179 err |= setup_sigcontext(&frame->uc.uc_mcontext, 180 regs, set->sig[0]); 181 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 182 183 /* Set up to return from userspace. If provided, use a stub 184 already in userspace. */ 185 /* minus 8 is offset to cater for "rtsd r15,8" */ 186 /* addi r12, r0, __NR_sigreturn */ 187 err |= __put_user(0x31800000 | __NR_rt_sigreturn , 188 frame->tramp + 0); 189 /* brki r14, 0x8 */ 190 err |= __put_user(0xb9cc0008, frame->tramp + 1); 191 192 /* Return from sighandler will jump to the tramp. 193 Negative 8 offset because return is rtsd r15, 8 */ 194 regs->r15 = ((unsigned long)frame->tramp)-8; 195 196 address = ((unsigned long)frame->tramp); 197 #ifdef CONFIG_MMU 198 pmdp = pmd_offset(pud_offset( 199 pgd_offset(current->mm, address), 200 address), address); 201 202 preempt_disable(); 203 ptep = pte_offset_map(pmdp, address); 204 if (pte_present(*ptep)) { 205 address = (unsigned long) page_address(pte_page(*ptep)); 206 /* MS: I need add offset in page */ 207 address += ((unsigned long)frame->tramp) & ~PAGE_MASK; 208 /* MS address is virtual */ 209 address = __virt_to_phys(address); 210 invalidate_icache_range(address, address + 8); 211 flush_dcache_range(address, address + 8); 212 } 213 pte_unmap(ptep); 214 preempt_enable(); 215 #else 216 flush_icache_range(address, address + 8); 217 flush_dcache_range(address, address + 8); 218 #endif 219 if (err) 220 return -EFAULT; 221 222 /* Set up registers for signal handler */ 223 regs->r1 = (unsigned long) frame; 224 225 /* Signal handler args: */ 226 regs->r5 = sig; /* arg 0: signum */ 227 regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */ 228 regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */ 229 /* Offset to handle microblaze rtid r14, 0 */ 230 regs->pc = (unsigned long)ksig->ka.sa.sa_handler; 231 232 #ifdef DEBUG_SIG 233 pr_info("SIG deliver (%s:%d): sp=%p pc=%08lx\n", 234 current->comm, current->pid, frame, regs->pc); 235 #endif 236 237 return 0; 238 } 239 240 /* Handle restarting system calls */ 241 static inline void 242 handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler) 243 { 244 switch (regs->r3) { 245 case -ERESTART_RESTARTBLOCK: 246 case -ERESTARTNOHAND: 247 if (!has_handler) 248 goto do_restart; 249 regs->r3 = -EINTR; 250 break; 251 case -ERESTARTSYS: 252 if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) { 253 regs->r3 = -EINTR; 254 break; 255 } 256 /* fallthrough */ 257 case -ERESTARTNOINTR: 258 do_restart: 259 /* offset of 4 bytes to re-execute trap (brki) instruction */ 260 regs->pc -= 4; 261 break; 262 } 263 } 264 265 /* 266 * OK, we're invoking a handler 267 */ 268 269 static void 270 handle_signal(struct ksignal *ksig, struct pt_regs *regs) 271 { 272 sigset_t *oldset = sigmask_to_save(); 273 int ret; 274 275 /* Set up the stack frame */ 276 ret = setup_rt_frame(ksig, oldset, regs); 277 278 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); 279 } 280 281 /* 282 * Note that 'init' is a special process: it doesn't get signals it doesn't 283 * want to handle. Thus you cannot kill init even with a SIGKILL even by 284 * mistake. 285 * 286 * Note that we go through the signals twice: once to check the signals that 287 * the kernel can handle, and then we build all the user-level signal handling 288 * stack-frames in one go after that. 289 */ 290 static void do_signal(struct pt_regs *regs, int in_syscall) 291 { 292 struct ksignal ksig; 293 294 #ifdef DEBUG_SIG 295 pr_info("do signal: %p %d\n", regs, in_syscall); 296 pr_info("do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1, 297 regs->r12, current_thread_info()->flags); 298 #endif 299 300 if (get_signal(&ksig)) { 301 /* Whee! Actually deliver the signal. */ 302 if (in_syscall) 303 handle_restart(regs, &ksig.ka, 1); 304 handle_signal(&ksig, regs); 305 return; 306 } 307 308 if (in_syscall) 309 handle_restart(regs, NULL, 0); 310 311 /* 312 * If there's no signal to deliver, we just put the saved sigmask 313 * back. 314 */ 315 restore_saved_sigmask(); 316 } 317 318 asmlinkage void do_notify_resume(struct pt_regs *regs, int in_syscall) 319 { 320 if (test_thread_flag(TIF_SIGPENDING)) 321 do_signal(regs, in_syscall); 322 323 if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) 324 tracehook_notify_resume(regs); 325 } 326