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 <linux/sched/task_stack.h> 25 26 #include <asm/registers.h> 27 #include <asm/thread_info.h> 28 #include <asm/unistd.h> 29 #include <linux/uaccess.h> 30 #include <asm/ucontext.h> 31 #include <asm/cacheflush.h> 32 #include <asm/signal.h> 33 #include <asm/vdso.h> 34 35 struct rt_sigframe { 36 unsigned long tramp[2]; 37 struct siginfo info; 38 struct ucontext uc; 39 }; 40 41 static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, 42 size_t frame_size) 43 { 44 unsigned long sp = sigsp(regs->r29, ksig); 45 46 return (void __user *)((sp - frame_size) & ~(sizeof(long long) - 1)); 47 } 48 49 static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) 50 { 51 unsigned long tmp; 52 int err = 0; 53 54 err |= copy_to_user(&sc->sc_regs.r0, ®s->r00, 55 32*sizeof(unsigned long)); 56 57 err |= __put_user(regs->sa0, &sc->sc_regs.sa0); 58 err |= __put_user(regs->lc0, &sc->sc_regs.lc0); 59 err |= __put_user(regs->sa1, &sc->sc_regs.sa1); 60 err |= __put_user(regs->lc1, &sc->sc_regs.lc1); 61 err |= __put_user(regs->m0, &sc->sc_regs.m0); 62 err |= __put_user(regs->m1, &sc->sc_regs.m1); 63 err |= __put_user(regs->usr, &sc->sc_regs.usr); 64 err |= __put_user(regs->preds, &sc->sc_regs.p3_0); 65 err |= __put_user(regs->gp, &sc->sc_regs.gp); 66 err |= __put_user(regs->ugp, &sc->sc_regs.ugp); 67 #if CONFIG_HEXAGON_ARCH_VERSION >= 4 68 err |= __put_user(regs->cs0, &sc->sc_regs.cs0); 69 err |= __put_user(regs->cs1, &sc->sc_regs.cs1); 70 #endif 71 tmp = pt_elr(regs); err |= __put_user(tmp, &sc->sc_regs.pc); 72 tmp = pt_cause(regs); err |= __put_user(tmp, &sc->sc_regs.cause); 73 tmp = pt_badva(regs); err |= __put_user(tmp, &sc->sc_regs.badva); 74 75 return err; 76 } 77 78 static int restore_sigcontext(struct pt_regs *regs, 79 struct sigcontext __user *sc) 80 { 81 unsigned long tmp; 82 int err = 0; 83 84 err |= copy_from_user(®s->r00, &sc->sc_regs.r0, 85 32 * sizeof(unsigned long)); 86 87 err |= __get_user(regs->sa0, &sc->sc_regs.sa0); 88 err |= __get_user(regs->lc0, &sc->sc_regs.lc0); 89 err |= __get_user(regs->sa1, &sc->sc_regs.sa1); 90 err |= __get_user(regs->lc1, &sc->sc_regs.lc1); 91 err |= __get_user(regs->m0, &sc->sc_regs.m0); 92 err |= __get_user(regs->m1, &sc->sc_regs.m1); 93 err |= __get_user(regs->usr, &sc->sc_regs.usr); 94 err |= __get_user(regs->preds, &sc->sc_regs.p3_0); 95 err |= __get_user(regs->gp, &sc->sc_regs.gp); 96 err |= __get_user(regs->ugp, &sc->sc_regs.ugp); 97 #if CONFIG_HEXAGON_ARCH_VERSION >= 4 98 err |= __get_user(regs->cs0, &sc->sc_regs.cs0); 99 err |= __get_user(regs->cs1, &sc->sc_regs.cs1); 100 #endif 101 err |= __get_user(tmp, &sc->sc_regs.pc); pt_set_elr(regs, tmp); 102 103 return err; 104 } 105 106 /* 107 * Setup signal stack frame with siginfo structure 108 */ 109 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, 110 struct pt_regs *regs) 111 { 112 int err = 0; 113 struct rt_sigframe __user *frame; 114 struct hexagon_vdso *vdso = current->mm->context.vdso; 115 116 frame = get_sigframe(ksig, regs, sizeof(struct rt_sigframe)); 117 118 if (!access_ok(VERIFY_WRITE, frame, sizeof(struct rt_sigframe))) 119 return -EFAULT; 120 121 if (copy_siginfo_to_user(&frame->info, &ksig->info)) 122 return -EFAULT; 123 124 /* The on-stack signal trampoline is no longer executed; 125 * however, the libgcc signal frame unwinding code checks for 126 * the presence of these two numeric magic values. 127 */ 128 err |= __put_user(0x7800d166, &frame->tramp[0]); 129 err |= __put_user(0x5400c004, &frame->tramp[1]); 130 err |= setup_sigcontext(regs, &frame->uc.uc_mcontext); 131 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 132 err |= __save_altstack(&frame->uc.uc_stack, user_stack_pointer(regs)); 133 if (err) 134 return -EFAULT; 135 136 /* Load r0/r1 pair with signumber/siginfo pointer... */ 137 regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32) 138 | (unsigned long long)ksig->sig; 139 regs->r02 = (unsigned long) &frame->uc; 140 regs->r31 = (unsigned long) vdso->rt_signal_trampoline; 141 pt_psp(regs) = (unsigned long) frame; 142 pt_set_elr(regs, (unsigned long)ksig->ka.sa.sa_handler); 143 144 return 0; 145 } 146 147 /* 148 * Setup invocation of signal handler 149 */ 150 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) 151 { 152 int ret; 153 154 /* 155 * If we're handling a signal that aborted a system call, 156 * set up the error return value before adding the signal 157 * frame to the stack. 158 */ 159 160 if (regs->syscall_nr >= 0) { 161 switch (regs->r00) { 162 case -ERESTART_RESTARTBLOCK: 163 case -ERESTARTNOHAND: 164 regs->r00 = -EINTR; 165 break; 166 case -ERESTARTSYS: 167 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { 168 regs->r00 = -EINTR; 169 break; 170 } 171 /* Fall through */ 172 case -ERESTARTNOINTR: 173 regs->r06 = regs->syscall_nr; 174 pt_set_elr(regs, pt_elr(regs) - 4); 175 regs->r00 = regs->restart_r0; 176 break; 177 default: 178 break; 179 } 180 } 181 182 /* 183 * Set up the stack frame; not doing the SA_SIGINFO thing. We 184 * only set up the rt_frame flavor. 185 */ 186 /* If there was an error on setup, no signal was delivered. */ 187 ret = setup_rt_frame(ksig, sigmask_to_save(), regs); 188 189 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); 190 } 191 192 /* 193 * Called from return-from-event code. 194 */ 195 void do_signal(struct pt_regs *regs) 196 { 197 struct ksignal ksig; 198 199 if (!user_mode(regs)) 200 return; 201 202 if (get_signal(&ksig)) { 203 handle_signal(&ksig, regs); 204 return; 205 } 206 207 /* 208 * No (more) signals; if we came from a system call, handle the restart. 209 */ 210 211 if (regs->syscall_nr >= 0) { 212 switch (regs->r00) { 213 case -ERESTARTNOHAND: 214 case -ERESTARTSYS: 215 case -ERESTARTNOINTR: 216 regs->r06 = regs->syscall_nr; 217 break; 218 case -ERESTART_RESTARTBLOCK: 219 regs->r06 = __NR_restart_syscall; 220 break; 221 default: 222 goto no_restart; 223 } 224 pt_set_elr(regs, pt_elr(regs) - 4); 225 regs->r00 = regs->restart_r0; 226 } 227 228 no_restart: 229 /* If there's no signal to deliver, put the saved sigmask back */ 230 restore_saved_sigmask(); 231 } 232 233 /* 234 * Architecture-specific wrappers for signal-related system calls 235 */ 236 237 asmlinkage int sys_rt_sigreturn(void) 238 { 239 struct pt_regs *regs = current_pt_regs(); 240 struct rt_sigframe __user *frame; 241 sigset_t blocked; 242 243 /* Always make any pending restarted system calls return -EINTR */ 244 current->restart_block.fn = do_no_restart_syscall; 245 246 frame = (struct rt_sigframe __user *)pt_psp(regs); 247 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 248 goto badframe; 249 if (__copy_from_user(&blocked, &frame->uc.uc_sigmask, sizeof(blocked))) 250 goto badframe; 251 252 set_current_blocked(&blocked); 253 254 if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) 255 goto badframe; 256 257 /* Restore the user's stack as well */ 258 pt_psp(regs) = regs->r29; 259 260 regs->syscall_nr = -1; 261 262 if (restore_altstack(&frame->uc.uc_stack)) 263 goto badframe; 264 265 return regs->r00; 266 267 badframe: 268 force_sig(SIGSEGV, current); 269 return 0; 270 } 271