1 /* 2 * Signal support for Hexagon processor 3 * 4 * Copyright (c) 2010-2012, The Linux Foundation. All rights reserved. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 and 8 * only version 2 as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 18 * 02110-1301, USA. 19 */ 20 21 #include <linux/linkage.h> 22 #include <linux/syscalls.h> 23 #include <linux/tracehook.h> 24 #include <asm/registers.h> 25 #include <asm/thread_info.h> 26 #include <asm/unistd.h> 27 #include <asm/uaccess.h> 28 #include <asm/ucontext.h> 29 #include <asm/cacheflush.h> 30 #include <asm/signal.h> 31 #include <asm/vdso.h> 32 33 struct rt_sigframe { 34 unsigned long tramp[2]; 35 struct siginfo info; 36 struct ucontext uc; 37 }; 38 39 static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, 40 size_t frame_size) 41 { 42 unsigned long sp = sigsp(regs->r29, ksig); 43 44 return (void __user *)((sp - frame_size) & ~(sizeof(long long) - 1)); 45 } 46 47 static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) 48 { 49 unsigned long tmp; 50 int err = 0; 51 52 err |= copy_to_user(&sc->sc_regs.r0, ®s->r00, 53 32*sizeof(unsigned long)); 54 55 err |= __put_user(regs->sa0, &sc->sc_regs.sa0); 56 err |= __put_user(regs->lc0, &sc->sc_regs.lc0); 57 err |= __put_user(regs->sa1, &sc->sc_regs.sa1); 58 err |= __put_user(regs->lc1, &sc->sc_regs.lc1); 59 err |= __put_user(regs->m0, &sc->sc_regs.m0); 60 err |= __put_user(regs->m1, &sc->sc_regs.m1); 61 err |= __put_user(regs->usr, &sc->sc_regs.usr); 62 err |= __put_user(regs->preds, &sc->sc_regs.p3_0); 63 err |= __put_user(regs->gp, &sc->sc_regs.gp); 64 err |= __put_user(regs->ugp, &sc->sc_regs.ugp); 65 #if CONFIG_HEXAGON_ARCH_VERSION >= 4 66 err |= __put_user(regs->cs0, &sc->sc_regs.cs0); 67 err |= __put_user(regs->cs1, &sc->sc_regs.cs1); 68 #endif 69 tmp = pt_elr(regs); err |= __put_user(tmp, &sc->sc_regs.pc); 70 tmp = pt_cause(regs); err |= __put_user(tmp, &sc->sc_regs.cause); 71 tmp = pt_badva(regs); err |= __put_user(tmp, &sc->sc_regs.badva); 72 73 return err; 74 } 75 76 static int restore_sigcontext(struct pt_regs *regs, 77 struct sigcontext __user *sc) 78 { 79 unsigned long tmp; 80 int err = 0; 81 82 err |= copy_from_user(®s->r00, &sc->sc_regs.r0, 83 32 * sizeof(unsigned long)); 84 85 err |= __get_user(regs->sa0, &sc->sc_regs.sa0); 86 err |= __get_user(regs->lc0, &sc->sc_regs.lc0); 87 err |= __get_user(regs->sa1, &sc->sc_regs.sa1); 88 err |= __get_user(regs->lc1, &sc->sc_regs.lc1); 89 err |= __get_user(regs->m0, &sc->sc_regs.m0); 90 err |= __get_user(regs->m1, &sc->sc_regs.m1); 91 err |= __get_user(regs->usr, &sc->sc_regs.usr); 92 err |= __get_user(regs->preds, &sc->sc_regs.p3_0); 93 err |= __get_user(regs->gp, &sc->sc_regs.gp); 94 err |= __get_user(regs->ugp, &sc->sc_regs.ugp); 95 #if CONFIG_HEXAGON_ARCH_VERSION >= 4 96 err |= __get_user(regs->cs0, &sc->sc_regs.cs0); 97 err |= __get_user(regs->cs1, &sc->sc_regs.cs1); 98 #endif 99 err |= __get_user(tmp, &sc->sc_regs.pc); pt_set_elr(regs, tmp); 100 101 return err; 102 } 103 104 /* 105 * Setup signal stack frame with siginfo structure 106 */ 107 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, 108 struct pt_regs *regs) 109 { 110 int err = 0; 111 struct rt_sigframe __user *frame; 112 struct hexagon_vdso *vdso = current->mm->context.vdso; 113 114 frame = get_sigframe(ksig, regs, sizeof(struct rt_sigframe)); 115 116 if (!access_ok(VERIFY_WRITE, frame, sizeof(struct rt_sigframe))) 117 return -EFAULT; 118 119 if (copy_siginfo_to_user(&frame->info, &ksig->info)) 120 return -EFAULT; 121 122 /* The on-stack signal trampoline is no longer executed; 123 * however, the libgcc signal frame unwinding code checks for 124 * the presence of these two numeric magic values. 125 */ 126 err |= __put_user(0x7800d166, &frame->tramp[0]); 127 err |= __put_user(0x5400c004, &frame->tramp[1]); 128 err |= setup_sigcontext(regs, &frame->uc.uc_mcontext); 129 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 130 err |= __save_altstack(&frame->uc.uc_stack, user_stack_pointer(regs)); 131 if (err) 132 return -EFAULT; 133 134 /* Load r0/r1 pair with signumber/siginfo pointer... */ 135 regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32) 136 | (unsigned long long)ksig->sig; 137 regs->r02 = (unsigned long) &frame->uc; 138 regs->r31 = (unsigned long) vdso->rt_signal_trampoline; 139 pt_psp(regs) = (unsigned long) frame; 140 pt_set_elr(regs, (unsigned long)ksig->ka.sa.sa_handler); 141 142 return 0; 143 } 144 145 /* 146 * Setup invocation of signal handler 147 */ 148 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) 149 { 150 int ret; 151 152 /* 153 * If we're handling a signal that aborted a system call, 154 * set up the error return value before adding the signal 155 * frame to the stack. 156 */ 157 158 if (regs->syscall_nr >= 0) { 159 switch (regs->r00) { 160 case -ERESTART_RESTARTBLOCK: 161 case -ERESTARTNOHAND: 162 regs->r00 = -EINTR; 163 break; 164 case -ERESTARTSYS: 165 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { 166 regs->r00 = -EINTR; 167 break; 168 } 169 /* Fall through */ 170 case -ERESTARTNOINTR: 171 regs->r06 = regs->syscall_nr; 172 pt_set_elr(regs, pt_elr(regs) - 4); 173 regs->r00 = regs->restart_r0; 174 break; 175 default: 176 break; 177 } 178 } 179 180 /* 181 * Set up the stack frame; not doing the SA_SIGINFO thing. We 182 * only set up the rt_frame flavor. 183 */ 184 /* If there was an error on setup, no signal was delivered. */ 185 ret = setup_rt_frame(ksig, sigmask_to_save(), regs); 186 187 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); 188 } 189 190 /* 191 * Called from return-from-event code. 192 */ 193 void do_signal(struct pt_regs *regs) 194 { 195 struct ksignal ksig; 196 197 if (!user_mode(regs)) 198 return; 199 200 if (get_signal(&ksig)) { 201 handle_signal(&ksig, regs); 202 return; 203 } 204 205 /* 206 * No (more) signals; if we came from a system call, handle the restart. 207 */ 208 209 if (regs->syscall_nr >= 0) { 210 switch (regs->r00) { 211 case -ERESTARTNOHAND: 212 case -ERESTARTSYS: 213 case -ERESTARTNOINTR: 214 regs->r06 = regs->syscall_nr; 215 break; 216 case -ERESTART_RESTARTBLOCK: 217 regs->r06 = __NR_restart_syscall; 218 break; 219 default: 220 goto no_restart; 221 } 222 pt_set_elr(regs, pt_elr(regs) - 4); 223 regs->r00 = regs->restart_r0; 224 } 225 226 no_restart: 227 /* If there's no signal to deliver, put the saved sigmask back */ 228 restore_saved_sigmask(); 229 } 230 231 /* 232 * Architecture-specific wrappers for signal-related system calls 233 */ 234 235 asmlinkage int sys_rt_sigreturn(void) 236 { 237 struct pt_regs *regs = current_pt_regs(); 238 struct rt_sigframe __user *frame; 239 sigset_t blocked; 240 241 /* Always make any pending restarted system calls return -EINTR */ 242 current_thread_info()->restart_block.fn = do_no_restart_syscall; 243 244 frame = (struct rt_sigframe __user *)pt_psp(regs); 245 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 246 goto badframe; 247 if (__copy_from_user(&blocked, &frame->uc.uc_sigmask, sizeof(blocked))) 248 goto badframe; 249 250 set_current_blocked(&blocked); 251 252 if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) 253 goto badframe; 254 255 /* Restore the user's stack as well */ 256 pt_psp(regs) = regs->r29; 257 258 regs->syscall_nr = -1; 259 260 if (restore_altstack(&frame->uc.uc_stack)) 261 goto badframe; 262 263 return regs->r00; 264 265 badframe: 266 force_sig(SIGSEGV, current); 267 return 0; 268 } 269