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#include <linux/tracehook.h> 20 21#include <asm/uaccess.h> 22#include <asm/ucontext.h> 23#include <asm/syscalls.h> 24 25#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) 26 27asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, 28 struct pt_regs *regs) 29{ 30 return do_sigaltstack(uss, uoss, regs->sp); 31} 32 33struct rt_sigframe 34{ 35 struct siginfo info; 36 struct ucontext uc; 37 unsigned long retcode; 38}; 39 40static int 41restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) 42{ 43 int err = 0; 44 45#define COPY(x) err |= __get_user(regs->x, &sc->x) 46 COPY(sr); 47 COPY(pc); 48 COPY(lr); 49 COPY(sp); 50 COPY(r12); 51 COPY(r11); 52 COPY(r10); 53 COPY(r9); 54 COPY(r8); 55 COPY(r7); 56 COPY(r6); 57 COPY(r5); 58 COPY(r4); 59 COPY(r3); 60 COPY(r2); 61 COPY(r1); 62 COPY(r0); 63#undef COPY 64 65 /* 66 * Don't allow anyone to pretend they're running in supervisor 67 * mode or something... 68 */ 69 err |= !valid_user_regs(regs); 70 71 return err; 72} 73 74 75asmlinkage int sys_rt_sigreturn(struct pt_regs *regs) 76{ 77 struct rt_sigframe __user *frame; 78 sigset_t set; 79 80 frame = (struct rt_sigframe __user *)regs->sp; 81 pr_debug("SIG return: frame = %p\n", frame); 82 83 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 84 goto badframe; 85 86 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 87 goto badframe; 88 89 sigdelsetmask(&set, ~_BLOCKABLE); 90 spin_lock_irq(¤t->sighand->siglock); 91 current->blocked = set; 92 recalc_sigpending(); 93 spin_unlock_irq(¤t->sighand->siglock); 94 95 if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) 96 goto badframe; 97 98 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT) 99 goto badframe; 100 101 pr_debug("Context restored: pc = %08lx, lr = %08lx, sp = %08lx\n", 102 regs->pc, regs->lr, regs->sp); 103 104 return regs->r12; 105 106badframe: 107 force_sig(SIGSEGV, current); 108 return 0; 109} 110 111static int 112setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs) 113{ 114 int err = 0; 115 116#define COPY(x) err |= __put_user(regs->x, &sc->x) 117 COPY(sr); 118 COPY(pc); 119 COPY(lr); 120 COPY(sp); 121 COPY(r12); 122 COPY(r11); 123 COPY(r10); 124 COPY(r9); 125 COPY(r8); 126 COPY(r7); 127 COPY(r6); 128 COPY(r5); 129 COPY(r4); 130 COPY(r3); 131 COPY(r2); 132 COPY(r1); 133 COPY(r0); 134#undef COPY 135 136 return err; 137} 138 139static inline void __user * 140get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize) 141{ 142 unsigned long sp = regs->sp; 143 144 if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp)) 145 sp = current->sas_ss_sp + current->sas_ss_size; 146 147 return (void __user *)((sp - framesize) & ~3); 148} 149 150static int 151setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, 152 sigset_t *set, struct pt_regs *regs) 153{ 154 struct rt_sigframe __user *frame; 155 int err = 0; 156 157 frame = get_sigframe(ka, regs, sizeof(*frame)); 158 err = -EFAULT; 159 if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame))) 160 goto out; 161 162 /* 163 * Set up the return code: 164 * 165 * mov r8, __NR_rt_sigreturn 166 * scall 167 * 168 * Note: This will blow up since we're using a non-executable 169 * stack. Better use SA_RESTORER. 170 */ 171#if __NR_rt_sigreturn > 127 172# error __NR_rt_sigreturn must be < 127 to fit in a short mov 173#endif 174 err = __put_user(0x3008d733 | (__NR_rt_sigreturn << 20), 175 &frame->retcode); 176 177 err |= copy_siginfo_to_user(&frame->info, info); 178 179 /* Set up the ucontext */ 180 err |= __put_user(0, &frame->uc.uc_flags); 181 err |= __put_user(NULL, &frame->uc.uc_link); 182 err |= __put_user((void __user *)current->sas_ss_sp, 183 &frame->uc.uc_stack.ss_sp); 184 err |= __put_user(sas_ss_flags(regs->sp), 185 &frame->uc.uc_stack.ss_flags); 186 err |= __put_user(current->sas_ss_size, 187 &frame->uc.uc_stack.ss_size); 188 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs); 189 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 190 191 if (err) 192 goto out; 193 194 regs->r12 = sig; 195 regs->r11 = (unsigned long) &frame->info; 196 regs->r10 = (unsigned long) &frame->uc; 197 regs->sp = (unsigned long) frame; 198 if (ka->sa.sa_flags & SA_RESTORER) 199 regs->lr = (unsigned long)ka->sa.sa_restorer; 200 else { 201 printk(KERN_NOTICE "[%s:%d] did not set SA_RESTORER\n", 202 current->comm, current->pid); 203 regs->lr = (unsigned long) &frame->retcode; 204 } 205 206 pr_debug("SIG deliver [%s:%d]: sig=%d sp=0x%lx pc=0x%lx->0x%p lr=0x%lx\n", 207 current->comm, current->pid, sig, regs->sp, 208 regs->pc, ka->sa.sa_handler, regs->lr); 209 210 regs->pc = (unsigned long) ka->sa.sa_handler; 211 212out: 213 return err; 214} 215 216static inline void setup_syscall_restart(struct pt_regs *regs) 217{ 218 if (regs->r12 == -ERESTART_RESTARTBLOCK) 219 regs->r8 = __NR_restart_syscall; 220 else 221 regs->r12 = regs->r12_orig; 222 regs->pc -= 2; 223} 224 225static inline void 226handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info, 227 sigset_t *oldset, struct pt_regs *regs, int syscall) 228{ 229 int ret; 230 231 /* 232 * Set up the stack frame 233 */ 234 ret = setup_rt_frame(sig, ka, info, oldset, regs); 235 236 /* 237 * Check that the resulting registers are sane 238 */ 239 ret |= !valid_user_regs(regs); 240 241 /* 242 * Block the signal if we were unsuccessful. 243 */ 244 if (ret != 0 || !(ka->sa.sa_flags & SA_NODEFER)) { 245 spin_lock_irq(¤t->sighand->siglock); 246 sigorsets(¤t->blocked, ¤t->blocked, 247 &ka->sa.sa_mask); 248 sigaddset(¤t->blocked, sig); 249 recalc_sigpending(); 250 spin_unlock_irq(¤t->sighand->siglock); 251 } 252 253 if (ret == 0) 254 return; 255 256 force_sigsegv(sig, current); 257} 258 259/* 260 * Note that 'init' is a special process: it doesn't get signals it 261 * doesn't want to handle. Thus you cannot kill init even with a 262 * SIGKILL even by mistake. 263 */ 264int do_signal(struct pt_regs *regs, sigset_t *oldset, int syscall) 265{ 266 siginfo_t info; 267 int signr; 268 struct k_sigaction ka; 269 270 /* 271 * We want the common case to go fast, which is why we may in 272 * certain cases get here from kernel mode. Just return 273 * without doing anything if so. 274 */ 275 if (!user_mode(regs)) 276 return 0; 277 278 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 279 oldset = ¤t->saved_sigmask; 280 else if (!oldset) 281 oldset = ¤t->blocked; 282 283 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 284 if (syscall) { 285 switch (regs->r12) { 286 case -ERESTART_RESTARTBLOCK: 287 case -ERESTARTNOHAND: 288 if (signr > 0) { 289 regs->r12 = -EINTR; 290 break; 291 } 292 /* fall through */ 293 case -ERESTARTSYS: 294 if (signr > 0 && !(ka.sa.sa_flags & SA_RESTART)) { 295 regs->r12 = -EINTR; 296 break; 297 } 298 /* fall through */ 299 case -ERESTARTNOINTR: 300 setup_syscall_restart(regs); 301 } 302 } 303 304 if (signr == 0) { 305 /* No signal to deliver -- put the saved sigmask back */ 306 if (test_thread_flag(TIF_RESTORE_SIGMASK)) { 307 clear_thread_flag(TIF_RESTORE_SIGMASK); 308 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); 309 } 310 return 0; 311 } 312 313 handle_signal(signr, &ka, &info, oldset, regs, syscall); 314 return 1; 315} 316 317asmlinkage void do_notify_resume(struct pt_regs *regs, struct thread_info *ti) 318{ 319 int syscall = 0; 320 321 if ((sysreg_read(SR) & MODE_MASK) == MODE_SUPERVISOR) 322 syscall = 1; 323 324 if (ti->flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK)) 325 do_signal(regs, ¤t->blocked, syscall); 326 327 if (ti->flags & _TIF_NOTIFY_RESUME) { 328 clear_thread_flag(TIF_NOTIFY_RESUME); 329 tracehook_notify_resume(regs); 330 if (current->replacement_session_keyring) 331 key_replace_session_keyring(); 332 } 333} 334