1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2010 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */ 28 /* All Rights Reserved */ 29 30 #include <sys/param.h> 31 #include <sys/types.h> 32 #include <sys/vmparam.h> 33 #include <sys/systm.h> 34 #include <sys/signal.h> 35 #include <sys/stack.h> 36 #include <sys/regset.h> 37 #include <sys/privregs.h> 38 #include <sys/frame.h> 39 #include <sys/proc.h> 40 #include <sys/brand.h> 41 #include <sys/psw.h> 42 #include <sys/ucontext.h> 43 #include <sys/asm_linkage.h> 44 #include <sys/errno.h> 45 #include <sys/archsystm.h> 46 #include <sys/schedctl.h> 47 #include <sys/debug.h> 48 #include <sys/sysmacros.h> 49 50 /* 51 * Save user context. 52 */ 53 void 54 savecontext(ucontext_t *ucp, const k_sigset_t *mask) 55 { 56 proc_t *p = ttoproc(curthread); 57 klwp_t *lwp = ttolwp(curthread); 58 struct regs *rp = lwptoregs(lwp); 59 60 /* 61 * We unconditionally assign to every field through the end 62 * of the gregs, but we need to bzero() everything -after- that 63 * to avoid having any kernel stack garbage escape to userland. 64 */ 65 bzero(&ucp->uc_mcontext.fpregs, sizeof (ucontext_t) - 66 offsetof(ucontext_t, uc_mcontext.fpregs)); 67 68 ucp->uc_flags = UC_ALL; 69 ucp->uc_link = (struct ucontext *)lwp->lwp_oldcontext; 70 71 /* 72 * Try to copyin() the ustack if one is registered. If the stack 73 * has zero size, this indicates that stack bounds checking has 74 * been disabled for this LWP. If stack bounds checking is disabled 75 * or the copyin() fails, we fall back to the legacy behavior. 76 */ 77 if (lwp->lwp_ustack == NULL || 78 copyin((void *)lwp->lwp_ustack, &ucp->uc_stack, 79 sizeof (ucp->uc_stack)) != 0 || 80 ucp->uc_stack.ss_size == 0) { 81 82 if (lwp->lwp_sigaltstack.ss_flags == SS_ONSTACK) { 83 ucp->uc_stack = lwp->lwp_sigaltstack; 84 } else { 85 ucp->uc_stack.ss_sp = p->p_usrstack - p->p_stksize; 86 ucp->uc_stack.ss_size = p->p_stksize; 87 ucp->uc_stack.ss_flags = 0; 88 } 89 } 90 91 /* 92 * If either the trace flag or REQUEST_STEP is set, 93 * arrange for single-stepping and turn off the trace flag. 94 */ 95 if ((rp->r_ps & PS_T) || (lwp->lwp_pcb.pcb_flags & REQUEST_STEP)) { 96 /* 97 * Clear PS_T so that saved user context won't have trace 98 * flag set. 99 */ 100 rp->r_ps &= ~PS_T; 101 102 if (!(lwp->lwp_pcb.pcb_flags & REQUEST_NOSTEP)) { 103 lwp->lwp_pcb.pcb_flags |= DEBUG_PENDING; 104 /* 105 * trap() always checks DEBUG_PENDING before 106 * checking for any pending signal. This at times 107 * can potentially lead to DEBUG_PENDING not being 108 * honoured. (for eg: the lwp is stopped by 109 * stop_on_fault() called from trap(), after being 110 * awakened it might see a pending signal and call 111 * savecontext(), however on the way back to userland 112 * there is no place it can be detected). Hence in 113 * anticipation of such occassions, set AST flag for 114 * the thread which will make the thread take an 115 * excursion through trap() where it will be handled 116 * appropriately. 117 */ 118 aston(curthread); 119 } 120 } 121 122 getgregs(lwp, ucp->uc_mcontext.gregs); 123 if (lwp->lwp_pcb.pcb_fpu.fpu_flags & FPU_EN) 124 getfpregs(lwp, &ucp->uc_mcontext.fpregs); 125 else 126 ucp->uc_flags &= ~UC_FPU; 127 128 sigktou(mask, &ucp->uc_sigmask); 129 } 130 131 /* 132 * Restore user context. 133 */ 134 void 135 restorecontext(ucontext_t *ucp) 136 { 137 kthread_t *t = curthread; 138 klwp_t *lwp = ttolwp(t); 139 140 lwp->lwp_oldcontext = (uintptr_t)ucp->uc_link; 141 142 if (ucp->uc_flags & UC_STACK) { 143 if (ucp->uc_stack.ss_flags == SS_ONSTACK) 144 lwp->lwp_sigaltstack = ucp->uc_stack; 145 else 146 lwp->lwp_sigaltstack.ss_flags &= ~SS_ONSTACK; 147 } 148 149 if (ucp->uc_flags & UC_CPU) { 150 /* 151 * If the trace flag is set, mark the lwp to take a 152 * single-step trap on return to user level (below). 153 * The x86 lcall interface and sysenter has already done this, 154 * and turned off the flag, but amd64 syscall interface has not. 155 */ 156 if (lwptoregs(lwp)->r_ps & PS_T) 157 lwp->lwp_pcb.pcb_flags |= DEBUG_PENDING; 158 setgregs(lwp, ucp->uc_mcontext.gregs); 159 lwp->lwp_eosys = JUSTRETURN; 160 t->t_post_sys = 1; 161 aston(curthread); 162 } 163 164 if (ucp->uc_flags & UC_FPU) 165 setfpregs(lwp, &ucp->uc_mcontext.fpregs); 166 167 if (ucp->uc_flags & UC_SIGMASK) { 168 /* 169 * We don't need to acquire p->p_lock here; 170 * we are manipulating thread-private data. 171 */ 172 schedctl_finish_sigblock(t); 173 sigutok(&ucp->uc_sigmask, &t->t_hold); 174 if (sigcheck(ttoproc(t), t)) 175 t->t_sig_check = 1; 176 } 177 } 178 179 180 int 181 getsetcontext(int flag, void *arg) 182 { 183 ucontext_t uc; 184 ucontext_t *ucp; 185 klwp_t *lwp = ttolwp(curthread); 186 stack_t dummy_stk; 187 188 /* 189 * In future releases, when the ucontext structure grows, 190 * getcontext should be modified to only return the fields 191 * specified in the uc_flags. That way, the structure can grow 192 * and still be binary compatible will all .o's which will only 193 * have old fields defined in uc_flags 194 */ 195 196 switch (flag) { 197 default: 198 return (set_errno(EINVAL)); 199 200 case GETCONTEXT: 201 schedctl_finish_sigblock(curthread); 202 savecontext(&uc, &curthread->t_hold); 203 if (uc.uc_flags & UC_SIGMASK) 204 SIGSET_NATIVE_TO_BRAND(&uc.uc_sigmask); 205 if (copyout(&uc, arg, sizeof (uc))) 206 return (set_errno(EFAULT)); 207 return (0); 208 209 case SETCONTEXT: 210 ucp = arg; 211 if (ucp == NULL) 212 exit(CLD_EXITED, 0); 213 /* 214 * Don't copyin filler or floating state unless we need it. 215 * The ucontext_t struct and fields are specified in the ABI. 216 */ 217 if (copyin(ucp, &uc, sizeof (ucontext_t) - 218 sizeof (uc.uc_filler) - 219 sizeof (uc.uc_mcontext.fpregs))) { 220 return (set_errno(EFAULT)); 221 } 222 if (uc.uc_flags & UC_SIGMASK) 223 SIGSET_BRAND_TO_NATIVE(&uc.uc_sigmask); 224 225 if ((uc.uc_flags & UC_FPU) && 226 copyin(&ucp->uc_mcontext.fpregs, &uc.uc_mcontext.fpregs, 227 sizeof (uc.uc_mcontext.fpregs))) { 228 return (set_errno(EFAULT)); 229 } 230 231 restorecontext(&uc); 232 233 if ((uc.uc_flags & UC_STACK) && (lwp->lwp_ustack != 0)) 234 (void) copyout(&uc.uc_stack, (stack_t *)lwp->lwp_ustack, 235 sizeof (uc.uc_stack)); 236 return (0); 237 238 case GETUSTACK: 239 if (copyout(&lwp->lwp_ustack, arg, sizeof (caddr_t))) 240 return (set_errno(EFAULT)); 241 return (0); 242 243 case SETUSTACK: 244 if (copyin(arg, &dummy_stk, sizeof (dummy_stk))) 245 return (set_errno(EFAULT)); 246 lwp->lwp_ustack = (uintptr_t)arg; 247 return (0); 248 } 249 } 250 251 #ifdef _SYSCALL32_IMPL 252 253 /* 254 * Save user context for 32-bit processes. 255 */ 256 void 257 savecontext32(ucontext32_t *ucp, const k_sigset_t *mask) 258 { 259 proc_t *p = ttoproc(curthread); 260 klwp_t *lwp = ttolwp(curthread); 261 struct regs *rp = lwptoregs(lwp); 262 263 bzero(&ucp->uc_mcontext.fpregs, sizeof (ucontext32_t) - 264 offsetof(ucontext32_t, uc_mcontext.fpregs)); 265 266 ucp->uc_flags = UC_ALL; 267 ucp->uc_link = (caddr32_t)lwp->lwp_oldcontext; 268 269 if (lwp->lwp_ustack == NULL || 270 copyin((void *)lwp->lwp_ustack, &ucp->uc_stack, 271 sizeof (ucp->uc_stack)) != 0 || 272 ucp->uc_stack.ss_size == 0) { 273 274 if (lwp->lwp_sigaltstack.ss_flags == SS_ONSTACK) { 275 ucp->uc_stack.ss_sp = 276 (caddr32_t)(uintptr_t)lwp->lwp_sigaltstack.ss_sp; 277 ucp->uc_stack.ss_size = 278 (size32_t)lwp->lwp_sigaltstack.ss_size; 279 ucp->uc_stack.ss_flags = SS_ONSTACK; 280 } else { 281 ucp->uc_stack.ss_sp = (caddr32_t)(uintptr_t) 282 (p->p_usrstack - p->p_stksize); 283 ucp->uc_stack.ss_size = (size32_t)p->p_stksize; 284 ucp->uc_stack.ss_flags = 0; 285 } 286 } 287 288 /* 289 * If either the trace flag or REQUEST_STEP is set, arrange 290 * for single-stepping and turn off the trace flag. 291 */ 292 if ((rp->r_ps & PS_T) || (lwp->lwp_pcb.pcb_flags & REQUEST_STEP)) { 293 /* 294 * Clear PS_T so that saved user context won't have trace 295 * flag set. 296 */ 297 rp->r_ps &= ~PS_T; 298 299 if (!(lwp->lwp_pcb.pcb_flags & REQUEST_NOSTEP)) { 300 lwp->lwp_pcb.pcb_flags |= DEBUG_PENDING; 301 /* 302 * See comments in savecontext(). 303 */ 304 aston(curthread); 305 } 306 } 307 308 getgregs32(lwp, ucp->uc_mcontext.gregs); 309 if (lwp->lwp_pcb.pcb_fpu.fpu_flags & FPU_EN) 310 getfpregs32(lwp, &ucp->uc_mcontext.fpregs); 311 else 312 ucp->uc_flags &= ~UC_FPU; 313 314 sigktou(mask, &ucp->uc_sigmask); 315 } 316 317 int 318 getsetcontext32(int flag, void *arg) 319 { 320 ucontext32_t uc; 321 ucontext_t ucnat; 322 ucontext32_t *ucp; 323 klwp_t *lwp = ttolwp(curthread); 324 caddr32_t ustack32; 325 stack32_t dummy_stk32; 326 327 switch (flag) { 328 default: 329 return (set_errno(EINVAL)); 330 331 case GETCONTEXT: 332 schedctl_finish_sigblock(curthread); 333 savecontext32(&uc, &curthread->t_hold); 334 if (uc.uc_flags & UC_SIGMASK) 335 SIGSET_NATIVE_TO_BRAND(&uc.uc_sigmask); 336 if (copyout(&uc, arg, sizeof (uc))) 337 return (set_errno(EFAULT)); 338 return (0); 339 340 case SETCONTEXT: 341 ucp = arg; 342 if (ucp == NULL) 343 exit(CLD_EXITED, 0); 344 if (copyin(ucp, &uc, sizeof (uc) - 345 sizeof (uc.uc_filler) - 346 sizeof (uc.uc_mcontext.fpregs))) { 347 return (set_errno(EFAULT)); 348 } 349 if (uc.uc_flags & UC_SIGMASK) 350 SIGSET_BRAND_TO_NATIVE(&uc.uc_sigmask); 351 if ((uc.uc_flags & UC_FPU) && 352 copyin(&ucp->uc_mcontext.fpregs, &uc.uc_mcontext.fpregs, 353 sizeof (uc.uc_mcontext.fpregs))) { 354 return (set_errno(EFAULT)); 355 } 356 357 ucontext_32ton(&uc, &ucnat); 358 restorecontext(&ucnat); 359 360 if ((uc.uc_flags & UC_STACK) && (lwp->lwp_ustack != 0)) 361 (void) copyout(&uc.uc_stack, 362 (stack32_t *)lwp->lwp_ustack, sizeof (uc.uc_stack)); 363 return (0); 364 365 case GETUSTACK: 366 ustack32 = (caddr32_t)lwp->lwp_ustack; 367 if (copyout(&ustack32, arg, sizeof (ustack32))) 368 return (set_errno(EFAULT)); 369 return (0); 370 371 case SETUSTACK: 372 if (copyin(arg, &dummy_stk32, sizeof (dummy_stk32))) 373 return (set_errno(EFAULT)); 374 lwp->lwp_ustack = (uintptr_t)arg; 375 return (0); 376 } 377 } 378 379 #endif /* _SYSCALL32_IMPL */ 380