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