1 /* 2 * Emulation of Linux signals 3 * 4 * Copyright (c) 2003 Fabrice Bellard 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 as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, see <http://www.gnu.org/licenses/>. 18 */ 19 #include "qemu/osdep.h" 20 #include "qemu.h" 21 #include "user-internals.h" 22 #include "signal-common.h" 23 #include "linux-user/trace.h" 24 25 /* 26 * code and data structures from linux kernel: 27 * include/asm-sh/sigcontext.h 28 * arch/sh/kernel/signal.c 29 */ 30 31 struct target_sigcontext { 32 target_ulong oldmask; 33 34 /* CPU registers */ 35 target_ulong sc_gregs[16]; 36 target_ulong sc_pc; 37 target_ulong sc_pr; 38 target_ulong sc_sr; 39 target_ulong sc_gbr; 40 target_ulong sc_mach; 41 target_ulong sc_macl; 42 43 /* FPU registers */ 44 target_ulong sc_fpregs[16]; 45 target_ulong sc_xfpregs[16]; 46 unsigned int sc_fpscr; 47 unsigned int sc_fpul; 48 unsigned int sc_ownedfp; 49 }; 50 51 struct target_sigframe 52 { 53 struct target_sigcontext sc; 54 target_ulong extramask[TARGET_NSIG_WORDS-1]; 55 }; 56 57 58 struct target_ucontext { 59 target_ulong tuc_flags; 60 struct target_ucontext *tuc_link; 61 target_stack_t tuc_stack; 62 struct target_sigcontext tuc_mcontext; 63 target_sigset_t tuc_sigmask; /* mask last for extensibility */ 64 }; 65 66 struct target_rt_sigframe 67 { 68 struct target_siginfo info; 69 struct target_ucontext uc; 70 }; 71 72 73 #define MOVW(n) (0x9300|((n)-2)) /* Move mem word at PC+n to R3 */ 74 #define TRAP_NOARG 0xc310 /* Syscall w/no args (NR in R3) SH3/4 */ 75 76 static abi_ulong get_sigframe(struct target_sigaction *ka, 77 unsigned long sp, size_t frame_size) 78 { 79 sp = target_sigsp(sp, ka); 80 81 return (sp - frame_size) & -8ul; 82 } 83 84 /* 85 * Notice when we're in the middle of a gUSA region and reset. 86 * Note that this will only occur when #CF_PARALLEL is unset, as we 87 * will translate such sequences differently in a parallel context. 88 */ 89 static void unwind_gusa(CPUSH4State *regs) 90 { 91 /* If the stack pointer is sufficiently negative, and we haven't 92 completed the sequence, then reset to the entry to the region. */ 93 /* ??? The SH4 kernel checks for and address above 0xC0000000. 94 However, the page mappings in qemu linux-user aren't as restricted 95 and we wind up with the normal stack mapped above 0xF0000000. 96 That said, there is no reason why the kernel should be allowing 97 a gUSA region that spans 1GB. Use a tighter check here, for what 98 can actually be enabled by the immediate move. */ 99 if (regs->gregs[15] >= -128u && regs->pc < regs->gregs[0]) { 100 /* Reset the PC to before the gUSA region, as computed from 101 R0 = region end, SP = -(region size), plus one more for the 102 insn that actually initializes SP to the region size. */ 103 regs->pc = regs->gregs[0] + regs->gregs[15] - 2; 104 105 /* Reset the SP to the saved version in R1. */ 106 regs->gregs[15] = regs->gregs[1]; 107 } else if (regs->gregs[15] >= -128u && regs->pc == regs->gregs[0]) { 108 /* If we are on the last instruction of a gUSA region, we must reset 109 the SP, otherwise we would be pushing the signal context to 110 invalid memory. */ 111 regs->gregs[15] = regs->gregs[1]; 112 } else if (regs->flags & TB_FLAG_DELAY_SLOT) { 113 /* If we are in a delay slot, push the previous instruction. */ 114 regs->pc -= 2; 115 } 116 } 117 118 static void setup_sigcontext(struct target_sigcontext *sc, 119 CPUSH4State *regs, unsigned long mask) 120 { 121 int i; 122 123 #define COPY(x) __put_user(regs->x, &sc->sc_##x) 124 COPY(gregs[0]); COPY(gregs[1]); 125 COPY(gregs[2]); COPY(gregs[3]); 126 COPY(gregs[4]); COPY(gregs[5]); 127 COPY(gregs[6]); COPY(gregs[7]); 128 COPY(gregs[8]); COPY(gregs[9]); 129 COPY(gregs[10]); COPY(gregs[11]); 130 COPY(gregs[12]); COPY(gregs[13]); 131 COPY(gregs[14]); COPY(gregs[15]); 132 COPY(gbr); COPY(mach); 133 COPY(macl); COPY(pr); 134 COPY(sr); COPY(pc); 135 #undef COPY 136 137 for (i=0; i<16; i++) { 138 __put_user(regs->fregs[i], &sc->sc_fpregs[i]); 139 } 140 __put_user(regs->fpscr, &sc->sc_fpscr); 141 __put_user(regs->fpul, &sc->sc_fpul); 142 143 /* non-iBCS2 extensions.. */ 144 __put_user(mask, &sc->oldmask); 145 } 146 147 static void restore_sigcontext(CPUSH4State *regs, struct target_sigcontext *sc) 148 { 149 int i; 150 151 #define COPY(x) __get_user(regs->x, &sc->sc_##x) 152 COPY(gregs[0]); COPY(gregs[1]); 153 COPY(gregs[2]); COPY(gregs[3]); 154 COPY(gregs[4]); COPY(gregs[5]); 155 COPY(gregs[6]); COPY(gregs[7]); 156 COPY(gregs[8]); COPY(gregs[9]); 157 COPY(gregs[10]); COPY(gregs[11]); 158 COPY(gregs[12]); COPY(gregs[13]); 159 COPY(gregs[14]); COPY(gregs[15]); 160 COPY(gbr); COPY(mach); 161 COPY(macl); COPY(pr); 162 COPY(sr); COPY(pc); 163 #undef COPY 164 165 for (i=0; i<16; i++) { 166 __get_user(regs->fregs[i], &sc->sc_fpregs[i]); 167 } 168 __get_user(regs->fpscr, &sc->sc_fpscr); 169 __get_user(regs->fpul, &sc->sc_fpul); 170 171 regs->tra = -1; /* disable syscall checks */ 172 regs->flags = 0; 173 } 174 175 void setup_frame(int sig, struct target_sigaction *ka, 176 target_sigset_t *set, CPUSH4State *regs) 177 { 178 struct target_sigframe *frame; 179 abi_ulong frame_addr; 180 int i; 181 182 unwind_gusa(regs); 183 184 frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame)); 185 trace_user_setup_frame(regs, frame_addr); 186 if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) { 187 goto give_sigsegv; 188 } 189 190 setup_sigcontext(&frame->sc, regs, set->sig[0]); 191 192 for (i = 0; i < TARGET_NSIG_WORDS - 1; i++) { 193 __put_user(set->sig[i + 1], &frame->extramask[i]); 194 } 195 196 /* Set up to return from userspace. If provided, use a stub 197 already in userspace. */ 198 if (ka->sa_flags & TARGET_SA_RESTORER) { 199 regs->pr = ka->sa_restorer; 200 } else { 201 regs->pr = default_sigreturn; 202 } 203 204 /* Set up registers for signal handler */ 205 regs->gregs[15] = frame_addr; 206 regs->gregs[4] = sig; /* Arg for signal handler */ 207 regs->gregs[5] = 0; 208 regs->gregs[6] = frame_addr += offsetof(typeof(*frame), sc); 209 regs->pc = (unsigned long) ka->_sa_handler; 210 regs->flags &= ~(TB_FLAG_DELAY_SLOT_MASK | TB_FLAG_GUSA_MASK); 211 212 unlock_user_struct(frame, frame_addr, 1); 213 return; 214 215 give_sigsegv: 216 unlock_user_struct(frame, frame_addr, 1); 217 force_sigsegv(sig); 218 } 219 220 void setup_rt_frame(int sig, struct target_sigaction *ka, 221 target_siginfo_t *info, 222 target_sigset_t *set, CPUSH4State *regs) 223 { 224 struct target_rt_sigframe *frame; 225 abi_ulong frame_addr; 226 int i; 227 228 unwind_gusa(regs); 229 230 frame_addr = get_sigframe(ka, regs->gregs[15], sizeof(*frame)); 231 trace_user_setup_rt_frame(regs, frame_addr); 232 if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) { 233 goto give_sigsegv; 234 } 235 236 tswap_siginfo(&frame->info, info); 237 238 /* Create the ucontext. */ 239 __put_user(0, &frame->uc.tuc_flags); 240 __put_user(0, (unsigned long *)&frame->uc.tuc_link); 241 target_save_altstack(&frame->uc.tuc_stack, regs); 242 setup_sigcontext(&frame->uc.tuc_mcontext, 243 regs, set->sig[0]); 244 for(i = 0; i < TARGET_NSIG_WORDS; i++) { 245 __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]); 246 } 247 248 /* Set up to return from userspace. If provided, use a stub 249 already in userspace. */ 250 if (ka->sa_flags & TARGET_SA_RESTORER) { 251 regs->pr = ka->sa_restorer; 252 } else { 253 regs->pr = default_rt_sigreturn; 254 } 255 256 /* Set up registers for signal handler */ 257 regs->gregs[15] = frame_addr; 258 regs->gregs[4] = sig; /* Arg for signal handler */ 259 regs->gregs[5] = frame_addr + offsetof(typeof(*frame), info); 260 regs->gregs[6] = frame_addr + offsetof(typeof(*frame), uc); 261 regs->pc = (unsigned long) ka->_sa_handler; 262 regs->flags &= ~(TB_FLAG_DELAY_SLOT_MASK | TB_FLAG_GUSA_MASK); 263 264 unlock_user_struct(frame, frame_addr, 1); 265 return; 266 267 give_sigsegv: 268 unlock_user_struct(frame, frame_addr, 1); 269 force_sigsegv(sig); 270 } 271 272 long do_sigreturn(CPUSH4State *regs) 273 { 274 struct target_sigframe *frame; 275 abi_ulong frame_addr; 276 sigset_t blocked; 277 target_sigset_t target_set; 278 int i; 279 280 frame_addr = regs->gregs[15]; 281 trace_user_do_sigreturn(regs, frame_addr); 282 if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) { 283 goto badframe; 284 } 285 286 __get_user(target_set.sig[0], &frame->sc.oldmask); 287 for(i = 1; i < TARGET_NSIG_WORDS; i++) { 288 __get_user(target_set.sig[i], &frame->extramask[i - 1]); 289 } 290 291 target_to_host_sigset_internal(&blocked, &target_set); 292 set_sigmask(&blocked); 293 294 restore_sigcontext(regs, &frame->sc); 295 296 unlock_user_struct(frame, frame_addr, 0); 297 return -QEMU_ESIGRETURN; 298 299 badframe: 300 unlock_user_struct(frame, frame_addr, 0); 301 force_sig(TARGET_SIGSEGV); 302 return -QEMU_ESIGRETURN; 303 } 304 305 long do_rt_sigreturn(CPUSH4State *regs) 306 { 307 struct target_rt_sigframe *frame; 308 abi_ulong frame_addr; 309 sigset_t blocked; 310 311 frame_addr = regs->gregs[15]; 312 trace_user_do_rt_sigreturn(regs, frame_addr); 313 if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) { 314 goto badframe; 315 } 316 317 target_to_host_sigset(&blocked, &frame->uc.tuc_sigmask); 318 set_sigmask(&blocked); 319 320 restore_sigcontext(regs, &frame->uc.tuc_mcontext); 321 target_restore_altstack(&frame->uc.tuc_stack, regs); 322 323 unlock_user_struct(frame, frame_addr, 0); 324 return -QEMU_ESIGRETURN; 325 326 badframe: 327 unlock_user_struct(frame, frame_addr, 0); 328 force_sig(TARGET_SIGSEGV); 329 return -QEMU_ESIGRETURN; 330 } 331 332 void setup_sigtramp(abi_ulong sigtramp_page) 333 { 334 uint16_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 * 6, 0); 335 assert(tramp != NULL); 336 337 default_sigreturn = sigtramp_page; 338 __put_user(MOVW(2), &tramp[0]); 339 __put_user(TRAP_NOARG, &tramp[1]); 340 __put_user(TARGET_NR_sigreturn, &tramp[2]); 341 342 default_rt_sigreturn = sigtramp_page + 6; 343 __put_user(MOVW(2), &tramp[3]); 344 __put_user(TRAP_NOARG, &tramp[4]); 345 __put_user(TARGET_NR_rt_sigreturn, &tramp[5]); 346 347 unlock_user(tramp, sigtramp_page, 2 * 6); 348 } 349