1/* 2 * Copyright (C) 2004-2006 Atmel Corporation 3 * 4 * Based on linux/arch/sh/kernel/signal.c 5 * Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima 6 * Copyright (C) 1991, 1992 Linus Torvalds 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 */ 12 13#include <linux/sched.h> 14#include <linux/mm.h> 15#include <linux/errno.h> 16#include <linux/ptrace.h> 17#include <linux/unistd.h> 18#include <linux/freezer.h> 19 20#include <asm/uaccess.h> 21#include <asm/ucontext.h> 22 23#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) 24 25asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, 26 struct pt_regs *regs) 27{ 28 return do_sigaltstack(uss, uoss, regs->sp); 29} 30 31struct rt_sigframe 32{ 33 struct siginfo info; 34 struct ucontext uc; 35 unsigned long retcode; 36}; 37 38static int 39restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) 40{ 41 int err = 0; 42 43#define COPY(x) err |= __get_user(regs->x, &sc->x) 44 COPY(sr); 45 COPY(pc); 46 COPY(lr); 47 COPY(sp); 48 COPY(r12); 49 COPY(r11); 50 COPY(r10); 51 COPY(r9); 52 COPY(r8); 53 COPY(r7); 54 COPY(r6); 55 COPY(r5); 56 COPY(r4); 57 COPY(r3); 58 COPY(r2); 59 COPY(r1); 60 COPY(r0); 61#undef COPY 62 63 /* 64 * Don't allow anyone to pretend they're running in supervisor 65 * mode or something... 66 */ 67 err |= !valid_user_regs(regs); 68 69 return err; 70} 71 72 73asmlinkage int sys_rt_sigreturn(struct pt_regs *regs) 74{ 75 struct rt_sigframe __user *frame; 76 sigset_t set; 77 78 frame = (struct rt_sigframe __user *)regs->sp; 79 pr_debug("SIG return: frame = %p\n", frame); 80 81 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 82 goto badframe; 83 84 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 85 goto badframe; 86 87 sigdelsetmask(&set, ~_BLOCKABLE); 88 spin_lock_irq(¤t->sighand->siglock); 89 current->blocked = set; 90 recalc_sigpending(); 91 spin_unlock_irq(¤t->sighand->siglock); 92 93 if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) 94 goto badframe; 95 96 pr_debug("Context restored: pc = %08lx, lr = %08lx, sp = %08lx\n", 97 regs->pc, regs->lr, regs->sp); 98 99 return regs->r12; 100 101badframe: 102 force_sig(SIGSEGV, current); 103 return 0; 104} 105 106static int 107setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs) 108{ 109 int err = 0; 110 111#define COPY(x) err |= __put_user(regs->x, &sc->x) 112 COPY(sr); 113 COPY(pc); 114 COPY(lr); 115 COPY(sp); 116 COPY(r12); 117 COPY(r11); 118 COPY(r10); 119 COPY(r9); 120 COPY(r8); 121 COPY(r7); 122 COPY(r6); 123 COPY(r5); 124 COPY(r4); 125 COPY(r3); 126 COPY(r2); 127 COPY(r1); 128 COPY(r0); 129#undef COPY 130 131 return err; 132} 133 134static inline void __user * 135get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize) 136{ 137 unsigned long sp = regs->sp; 138 139 if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp)) 140 sp = current->sas_ss_sp + current->sas_ss_size; 141 142 return (void __user *)((sp - framesize) & ~3); 143} 144 145static int 146setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, 147 sigset_t *set, struct pt_regs *regs) 148{ 149 struct rt_sigframe __user *frame; 150 int err = 0; 151 152 frame = get_sigframe(ka, regs, sizeof(*frame)); 153 err = -EFAULT; 154 if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame))) 155 goto out; 156 157 /* 158 * Set up the return code: 159 * 160 * mov r8, __NR_rt_sigreturn 161 * scall 162 * 163 * Note: This will blow up since we're using a non-executable 164 * stack. Better use SA_RESTORER. 165 */ 166#if __NR_rt_sigreturn > 127 167# error __NR_rt_sigreturn must be < 127 to fit in a short mov 168#endif 169 err = __put_user(0x3008d733 | (__NR_rt_sigreturn << 20), 170 &frame->retcode); 171 172 err |= copy_siginfo_to_user(&frame->info, info); 173 174 /* Set up the ucontext */ 175 err |= __put_user(0, &frame->uc.uc_flags); 176 err |= __put_user(NULL, &frame->uc.uc_link); 177 err |= __put_user((void __user *)current->sas_ss_sp, 178 &frame->uc.uc_stack.ss_sp); 179 err |= __put_user(sas_ss_flags(regs->sp), 180 &frame->uc.uc_stack.ss_flags); 181 err |= __put_user(current->sas_ss_size, 182 &frame->uc.uc_stack.ss_size); 183 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs); 184 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 185 186 if (err) 187 goto out; 188 189 regs->r12 = sig; 190 regs->r11 = (unsigned long) &frame->info; 191 regs->r10 = (unsigned long) &frame->uc; 192 regs->sp = (unsigned long) frame; 193 if (ka->sa.sa_flags & SA_RESTORER) 194 regs->lr = (unsigned long)ka->sa.sa_restorer; 195 else { 196 printk(KERN_NOTICE "[%s:%d] did not set SA_RESTORER\n", 197 current->comm, current->pid); 198 regs->lr = (unsigned long) &frame->retcode; 199 } 200 201 pr_debug("SIG deliver [%s:%d]: sig=%d sp=0x%lx pc=0x%lx->0x%p lr=0x%lx\n", 202 current->comm, current->pid, sig, regs->sp, 203 regs->pc, ka->sa.sa_handler, regs->lr); 204 205 regs->pc = (unsigned long) ka->sa.sa_handler; 206 207out: 208 return err; 209} 210 211static inline void restart_syscall(struct pt_regs *regs) 212{ 213 if (regs->r12 == -ERESTART_RESTARTBLOCK) 214 regs->r8 = __NR_restart_syscall; 215 else 216 regs->r12 = regs->r12_orig; 217 regs->pc -= 2; 218} 219 220static inline void 221handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info, 222 sigset_t *oldset, struct pt_regs *regs, int syscall) 223{ 224 int ret; 225 226 /* 227 * Set up the stack frame 228 */ 229 ret = setup_rt_frame(sig, ka, info, oldset, regs); 230 231 /* 232 * Check that the resulting registers are sane 233 */ 234 ret |= !valid_user_regs(regs); 235 236 /* 237 * Block the signal if we were unsuccessful. 238 */ 239 if (ret != 0 || !(ka->sa.sa_flags & SA_NODEFER)) { 240 spin_lock_irq(¤t->sighand->siglock); 241 sigorsets(¤t->blocked, ¤t->blocked, 242 &ka->sa.sa_mask); 243 sigaddset(¤t->blocked, sig); 244 recalc_sigpending(); 245 spin_unlock_irq(¤t->sighand->siglock); 246 } 247 248 if (ret == 0) 249 return; 250 251 force_sigsegv(sig, current); 252} 253 254/* 255 * Note that 'init' is a special process: it doesn't get signals it 256 * doesn't want to handle. Thus you cannot kill init even with a 257 * SIGKILL even by mistake. 258 */ 259int do_signal(struct pt_regs *regs, sigset_t *oldset, int syscall) 260{ 261 siginfo_t info; 262 int signr; 263 struct k_sigaction ka; 264 265 /* 266 * We want the common case to go fast, which is why we may in 267 * certain cases get here from kernel mode. Just return 268 * without doing anything if so. 269 */ 270 if (!user_mode(regs)) 271 return 0; 272 273 if (try_to_freeze()) { 274 signr = 0; 275 if (!signal_pending(current)) 276 goto no_signal; 277 } 278 279 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 280 oldset = ¤t->saved_sigmask; 281 else if (!oldset) 282 oldset = ¤t->blocked; 283 284 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 285no_signal: 286 if (syscall) { 287 switch (regs->r12) { 288 case -ERESTART_RESTARTBLOCK: 289 case -ERESTARTNOHAND: 290 if (signr > 0) { 291 regs->r12 = -EINTR; 292 break; 293 } 294 /* fall through */ 295 case -ERESTARTSYS: 296 if (signr > 0 && !(ka.sa.sa_flags & SA_RESTART)) { 297 regs->r12 = -EINTR; 298 break; 299 } 300 /* fall through */ 301 case -ERESTARTNOINTR: 302 restart_syscall(regs); 303 } 304 } 305 306 if (signr == 0) { 307 /* No signal to deliver -- put the saved sigmask back */ 308 if (test_thread_flag(TIF_RESTORE_SIGMASK)) { 309 clear_thread_flag(TIF_RESTORE_SIGMASK); 310 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); 311 } 312 return 0; 313 } 314 315 handle_signal(signr, &ka, &info, oldset, regs, syscall); 316 return 1; 317} 318 319asmlinkage void do_notify_resume(struct pt_regs *regs, struct thread_info *ti) 320{ 321 int syscall = 0; 322 323 if ((sysreg_read(SR) & MODE_MASK) == MODE_SUPERVISOR) 324 syscall = 1; 325 326 if (ti->flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK)) 327 do_signal(regs, ¤t->blocked, syscall); 328} 329