1/* 2 * File: arch/blackfin/kernel/signal.c 3 * Based on: 4 * Author: 5 * 6 * Created: 7 * Description: 8 * 9 * Modified: 10 * Copyright 2004-2006 Analog Devices Inc. 11 * 12 * Bugs: Enter bugs at http://blackfin.uclinux.org/ 13 * 14 * This program is free software; you can redistribute it and/or modify 15 * it under the terms of the GNU General Public License as published by 16 * the Free Software Foundation; either version 2 of the License, or 17 * (at your option) any later version. 18 * 19 * This program is distributed in the hope that it will be useful, 20 * but WITHOUT ANY WARRANTY; without even the implied warranty of 21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 22 * GNU General Public License for more details. 23 * 24 * You should have received a copy of the GNU General Public License 25 * along with this program; if not, see the file COPYING, or write 26 * to the Free Software Foundation, Inc., 27 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 28 */ 29 30#include <linux/signal.h> 31#include <linux/syscalls.h> 32#include <linux/ptrace.h> 33#include <linux/tty.h> 34#include <linux/personality.h> 35#include <linux/binfmts.h> 36#include <linux/freezer.h> 37 38#include <asm/uaccess.h> 39#include <asm/cacheflush.h> 40#include <asm/ucontext.h> 41 42#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) 43 44struct fdpic_func_descriptor { 45 unsigned long text; 46 unsigned long GOT; 47}; 48 49struct rt_sigframe { 50 int sig; 51 struct siginfo *pinfo; 52 void *puc; 53 char retcode[8]; 54 struct siginfo info; 55 struct ucontext uc; 56}; 57 58asmlinkage int sys_sigaltstack(const stack_t * uss, stack_t * uoss) 59{ 60 return do_sigaltstack(uss, uoss, rdusp()); 61} 62 63static inline int 64rt_restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc, int *pr0) 65{ 66 unsigned long usp = 0; 67 int err = 0; 68 69#define RESTORE(x) err |= __get_user(regs->x, &sc->sc_##x) 70 71 /* restore passed registers */ 72 RESTORE(r0); RESTORE(r1); RESTORE(r2); RESTORE(r3); 73 RESTORE(r4); RESTORE(r5); RESTORE(r6); RESTORE(r7); 74 RESTORE(p0); RESTORE(p1); RESTORE(p2); RESTORE(p3); 75 RESTORE(p4); RESTORE(p5); 76 err |= __get_user(usp, &sc->sc_usp); 77 wrusp(usp); 78 RESTORE(a0w); RESTORE(a1w); 79 RESTORE(a0x); RESTORE(a1x); 80 RESTORE(astat); 81 RESTORE(rets); 82 RESTORE(pc); 83 RESTORE(retx); 84 RESTORE(fp); 85 RESTORE(i0); RESTORE(i1); RESTORE(i2); RESTORE(i3); 86 RESTORE(m0); RESTORE(m1); RESTORE(m2); RESTORE(m3); 87 RESTORE(l0); RESTORE(l1); RESTORE(l2); RESTORE(l3); 88 RESTORE(b0); RESTORE(b1); RESTORE(b2); RESTORE(b3); 89 RESTORE(lc0); RESTORE(lc1); 90 RESTORE(lt0); RESTORE(lt1); 91 RESTORE(lb0); RESTORE(lb1); 92 RESTORE(seqstat); 93 94 regs->orig_p0 = -1; /* disable syscall checks */ 95 96 *pr0 = regs->r0; 97 return err; 98} 99 100asmlinkage int do_rt_sigreturn(unsigned long __unused) 101{ 102 struct pt_regs *regs = (struct pt_regs *)__unused; 103 unsigned long usp = rdusp(); 104 struct rt_sigframe *frame = (struct rt_sigframe *)(usp); 105 sigset_t set; 106 int r0; 107 108 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 109 goto badframe; 110 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 111 goto badframe; 112 113 sigdelsetmask(&set, ~_BLOCKABLE); 114 spin_lock_irq(¤t->sighand->siglock); 115 current->blocked = set; 116 recalc_sigpending(); 117 spin_unlock_irq(¤t->sighand->siglock); 118 119 if (rt_restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0)) 120 goto badframe; 121 122 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->usp) == -EFAULT) 123 goto badframe; 124 125 return r0; 126 127 badframe: 128 force_sig(SIGSEGV, current); 129 return 0; 130} 131 132static inline int rt_setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs) 133{ 134 int err = 0; 135 136#define SETUP(x) err |= __put_user(regs->x, &sc->sc_##x) 137 138 SETUP(r0); SETUP(r1); SETUP(r2); SETUP(r3); 139 SETUP(r4); SETUP(r5); SETUP(r6); SETUP(r7); 140 SETUP(p0); SETUP(p1); SETUP(p2); SETUP(p3); 141 SETUP(p4); SETUP(p5); 142 err |= __put_user(rdusp(), &sc->sc_usp); 143 SETUP(a0w); SETUP(a1w); 144 SETUP(a0x); SETUP(a1x); 145 SETUP(astat); 146 SETUP(rets); 147 SETUP(pc); 148 SETUP(retx); 149 SETUP(fp); 150 SETUP(i0); SETUP(i1); SETUP(i2); SETUP(i3); 151 SETUP(m0); SETUP(m1); SETUP(m2); SETUP(m3); 152 SETUP(l0); SETUP(l1); SETUP(l2); SETUP(l3); 153 SETUP(b0); SETUP(b1); SETUP(b2); SETUP(b3); 154 SETUP(lc0); SETUP(lc1); 155 SETUP(lt0); SETUP(lt1); 156 SETUP(lb0); SETUP(lb1); 157 SETUP(seqstat); 158 159 return err; 160} 161 162static inline void push_cache(unsigned long vaddr, unsigned int len) 163{ 164 flush_icache_range(vaddr, vaddr + len); 165} 166 167static inline void *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, 168 size_t frame_size) 169{ 170 unsigned long usp; 171 172 /* Default to using normal stack. */ 173 usp = rdusp(); 174 175 /* This is the X/Open sanctioned signal stack switching. */ 176 if (ka->sa.sa_flags & SA_ONSTACK) { 177 if (!on_sig_stack(usp)) 178 usp = current->sas_ss_sp + current->sas_ss_size; 179 } 180 return (void *)((usp - frame_size) & -8UL); 181} 182 183static int 184setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t * info, 185 sigset_t * set, struct pt_regs *regs) 186{ 187 struct rt_sigframe *frame; 188 int err = 0; 189 190 frame = get_sigframe(ka, regs, sizeof(*frame)); 191 192 err |= __put_user((current_thread_info()->exec_domain 193 && current_thread_info()->exec_domain->signal_invmap 194 && sig < 32 195 ? current_thread_info()->exec_domain-> 196 signal_invmap[sig] : sig), &frame->sig); 197 198 err |= __put_user(&frame->info, &frame->pinfo); 199 err |= __put_user(&frame->uc, &frame->puc); 200 err |= copy_siginfo_to_user(&frame->info, info); 201 202 /* Create the ucontext. */ 203 err |= __put_user(0, &frame->uc.uc_flags); 204 err |= __put_user(0, &frame->uc.uc_link); 205 err |= 206 __put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp); 207 err |= __put_user(sas_ss_flags(rdusp()), &frame->uc.uc_stack.ss_flags); 208 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); 209 err |= rt_setup_sigcontext(&frame->uc.uc_mcontext, regs); 210 err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 211 212 /* Set up to return from userspace. */ 213 err |= __put_user(0x28, &(frame->retcode[0])); 214 err |= __put_user(0xe1, &(frame->retcode[1])); 215 err |= __put_user(0xad, &(frame->retcode[2])); 216 err |= __put_user(0x00, &(frame->retcode[3])); 217 err |= __put_user(0xa0, &(frame->retcode[4])); 218 err |= __put_user(0x00, &(frame->retcode[5])); 219 220 if (err) 221 goto give_sigsegv; 222 223 push_cache((unsigned long)&frame->retcode, sizeof(frame->retcode)); 224 225 /* Set up registers for signal handler */ 226 wrusp((unsigned long)frame); 227 if (get_personality & FDPIC_FUNCPTRS) { 228 struct fdpic_func_descriptor __user *funcptr = 229 (struct fdpic_func_descriptor *) ka->sa.sa_handler; 230 __get_user(regs->pc, &funcptr->text); 231 __get_user(regs->p3, &funcptr->GOT); 232 } else 233 regs->pc = (unsigned long)ka->sa.sa_handler; 234 regs->rets = (unsigned long)(frame->retcode); 235 236 regs->r0 = frame->sig; 237 regs->r1 = (unsigned long)(&frame->info); 238 regs->r2 = (unsigned long)(&frame->uc); 239 240 return 0; 241 242 give_sigsegv: 243 if (sig == SIGSEGV) 244 ka->sa.sa_handler = SIG_DFL; 245 force_sig(SIGSEGV, current); 246 return -EFAULT; 247} 248 249static inline void 250handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler) 251{ 252 switch (regs->r0) { 253 case -ERESTARTNOHAND: 254 if (!has_handler) 255 goto do_restart; 256 regs->r0 = -EINTR; 257 break; 258 259 case -ERESTARTSYS: 260 if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) { 261 regs->r0 = -EINTR; 262 break; 263 } 264 /* fallthrough */ 265 case -ERESTARTNOINTR: 266 do_restart: 267 regs->p0 = regs->orig_p0; 268 regs->r0 = regs->orig_r0; 269 regs->pc -= 2; 270 break; 271 } 272} 273 274/* 275 * OK, we're invoking a handler 276 */ 277static int 278handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka, 279 sigset_t *oldset, struct pt_regs *regs) 280{ 281 int ret; 282 283 /* are we from a system call? to see pt_regs->orig_p0 */ 284 if (regs->orig_p0 >= 0) 285 /* If so, check system call restarting.. */ 286 handle_restart(regs, ka, 1); 287 288 /* set up the stack frame */ 289 ret = setup_rt_frame(sig, ka, info, oldset, regs); 290 291 if (ret == 0) { 292 spin_lock_irq(¤t->sighand->siglock); 293 sigorsets(¤t->blocked, ¤t->blocked, 294 &ka->sa.sa_mask); 295 if (!(ka->sa.sa_flags & SA_NODEFER)) 296 sigaddset(¤t->blocked, sig); 297 recalc_sigpending(); 298 spin_unlock_irq(¤t->sighand->siglock); 299 } 300 return ret; 301} 302 303/* 304 * Note that 'init' is a special process: it doesn't get signals it doesn't 305 * want to handle. Thus you cannot kill init even with a SIGKILL even by 306 * mistake. 307 * 308 * Note that we go through the signals twice: once to check the signals 309 * that the kernel can handle, and then we build all the user-level signal 310 * handling stack-frames in one go after that. 311 */ 312asmlinkage void do_signal(struct pt_regs *regs) 313{ 314 siginfo_t info; 315 int signr; 316 struct k_sigaction ka; 317 sigset_t *oldset; 318 319 current->thread.esp0 = (unsigned long)regs; 320 321 if (try_to_freeze()) 322 goto no_signal; 323 324 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 325 oldset = ¤t->saved_sigmask; 326 else 327 oldset = ¤t->blocked; 328 329 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 330 if (signr > 0) { 331 /* Whee! Actually deliver the signal. */ 332 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) { 333 /* a signal was successfully delivered; the saved 334 * sigmask will have been stored in the signal frame, 335 * and will be restored by sigreturn, so we can simply 336 * clear the TIF_RESTORE_SIGMASK flag */ 337 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 338 clear_thread_flag(TIF_RESTORE_SIGMASK); 339 } 340 341 return; 342 } 343 344no_signal: 345 /* Did we come from a system call? */ 346 if (regs->orig_p0 >= 0) 347 /* Restart the system call - no handlers present */ 348 handle_restart(regs, NULL, 0); 349 350 /* if there's no signal to deliver, we just put the saved sigmask 351 * back */ 352 if (test_thread_flag(TIF_RESTORE_SIGMASK)) { 353 clear_thread_flag(TIF_RESTORE_SIGMASK); 354 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); 355 } 356} 357