LXR linux/arch/s390/kernel/compat

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *    Copyright IBM Corp. 2000, 2006
   4 *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
   5 *               Gerhard Tonn (ton@de.ibm.com)                  
   6 *
   7 *  Copyright (C) 1991, 1992  Linus Torvalds
   8 *
   9 *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
  10 */
  11
  12#include <linux/compat.h>
  13#include <linux/sched.h>
  14#include <linux/sched/task_stack.h>
  15#include <linux/mm.h>
  16#include <linux/smp.h>
  17#include <linux/kernel.h>
  18#include <linux/signal.h>
  19#include <linux/errno.h>
  20#include <linux/wait.h>
  21#include <linux/ptrace.h>
  22#include <linux/unistd.h>
  23#include <linux/stddef.h>
  24#include <linux/tty.h>
  25#include <linux/personality.h>
  26#include <linux/binfmts.h>
  27#include <asm/ucontext.h>
  28#include <linux/uaccess.h>
  29#include <asm/lowcore.h>
  30#include <asm/switch_to.h>
  31#include "compat_linux.h"
  32#include "compat_ptrace.h"
  33#include "entry.h"
  34
  35typedef struct 
  36{
  37        __u8 callee_used_stack[__SIGNAL_FRAMESIZE32];
  38        struct sigcontext32 sc;
  39        _sigregs32 sregs;
  40        int signo;
  41        _sigregs_ext32 sregs_ext;
  42        __u16 svc_insn;         /* Offset of svc_insn is NOT fixed! */
  43} sigframe32;
  44
  45typedef struct 
  46{
  47        __u8 callee_used_stack[__SIGNAL_FRAMESIZE32];
  48        __u16 svc_insn;
  49        compat_siginfo_t info;
  50        struct ucontext32 uc;
  51} rt_sigframe32;
  52
  53/* Store registers needed to create the signal frame */
  54static void store_sigregs(void)
  55{
  56        save_access_regs(current->thread.acrs);
  57        save_fpu_regs();
  58}
  59
  60/* Load registers after signal return */
  61static void load_sigregs(void)
  62{
  63        restore_access_regs(current->thread.acrs);
  64}
  65
  66static int save_sigregs32(struct pt_regs *regs, _sigregs32 __user *sregs)
  67{
  68        _sigregs32 user_sregs;
  69        int i;
  70
  71        user_sregs.regs.psw.mask = (__u32)(regs->psw.mask >> 32);
  72        user_sregs.regs.psw.mask &= PSW32_MASK_USER | PSW32_MASK_RI;
  73        user_sregs.regs.psw.mask |= PSW32_USER_BITS;
  74        user_sregs.regs.psw.addr = (__u32) regs->psw.addr |
  75                (__u32)(regs->psw.mask & PSW_MASK_BA);
  76        for (i = 0; i < NUM_GPRS; i++)
  77                user_sregs.regs.gprs[i] = (__u32) regs->gprs[i];
  78        memcpy(&user_sregs.regs.acrs, current->thread.acrs,
  79               sizeof(user_sregs.regs.acrs));
  80        fpregs_store((_s390_fp_regs *) &user_sregs.fpregs, &current->thread.fpu);
  81        if (__copy_to_user(sregs, &user_sregs, sizeof(_sigregs32)))
  82                return -EFAULT;
  83        return 0;
  84}
  85
  86static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs)
  87{
  88        _sigregs32 user_sregs;
  89        int i;
  90
  91        /* Alwys make any pending restarted system call return -EINTR */
  92        current->restart_block.fn = do_no_restart_syscall;
  93
  94        if (__copy_from_user(&user_sregs, &sregs->regs, sizeof(user_sregs)))
  95                return -EFAULT;
  96
  97        if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW32_MASK_RI))
  98                return -EINVAL;
  99
 100        /* Test the floating-point-control word. */
 101        if (test_fp_ctl(user_sregs.fpregs.fpc))
 102                return -EINVAL;
 103
 104        /* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
 105        regs->psw.mask = (regs->psw.mask & ~(PSW_MASK_USER | PSW_MASK_RI)) |
 106                (__u64)(user_sregs.regs.psw.mask & PSW32_MASK_USER) << 32 |
 107                (__u64)(user_sregs.regs.psw.mask & PSW32_MASK_RI) << 32 |
 108                (__u64)(user_sregs.regs.psw.addr & PSW32_ADDR_AMODE);
 109        /* Check for invalid user address space control. */
 110        if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
 111                regs->psw.mask = PSW_ASC_PRIMARY |
 112                        (regs->psw.mask & ~PSW_MASK_ASC);
 113        regs->psw.addr = (__u64)(user_sregs.regs.psw.addr & PSW32_ADDR_INSN);
 114        for (i = 0; i < NUM_GPRS; i++)
 115                regs->gprs[i] = (__u64) user_sregs.regs.gprs[i];
 116        memcpy(&current->thread.acrs, &user_sregs.regs.acrs,
 117               sizeof(current->thread.acrs));
 118        fpregs_load((_s390_fp_regs *) &user_sregs.fpregs, &current->thread.fpu);
 119
 120        clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */
 121        clear_pt_regs_flag(regs, PIF_SYSCALL_RESTART);
 122        return 0;
 123}
 124
 125static int save_sigregs_ext32(struct pt_regs *regs,
 126                              _sigregs_ext32 __user *sregs_ext)
 127{
 128        __u32 gprs_high[NUM_GPRS];
 129        __u64 vxrs[__NUM_VXRS_LOW];
 130        int i;
 131
 132        /* Save high gprs to signal stack */
 133        for (i = 0; i < NUM_GPRS; i++)
 134                gprs_high[i] = regs->gprs[i] >> 32;
 135        if (__copy_to_user(&sregs_ext->gprs_high, &gprs_high,
 136                           sizeof(sregs_ext->gprs_high)))
 137                return -EFAULT;
 138
 139        /* Save vector registers to signal stack */
 140        if (MACHINE_HAS_VX) {
 141                for (i = 0; i < __NUM_VXRS_LOW; i++)
 142                        vxrs[i] = *((__u64 *)(current->thread.fpu.vxrs + i) + 1);
 143                if (__copy_to_user(&sregs_ext->vxrs_low, vxrs,
 144                                   sizeof(sregs_ext->vxrs_low)) ||
 145                    __copy_to_user(&sregs_ext->vxrs_high,
 146                                   current->thread.fpu.vxrs + __NUM_VXRS_LOW,
 147                                   sizeof(sregs_ext->vxrs_high)))
 148                        return -EFAULT;
 149        }
 150        return 0;
 151}
 152
 153static int restore_sigregs_ext32(struct pt_regs *regs,
 154                                 _sigregs_ext32 __user *sregs_ext)
 155{
 156        __u32 gprs_high[NUM_GPRS];
 157        __u64 vxrs[__NUM_VXRS_LOW];
 158        int i;
 159
 160        /* Restore high gprs from signal stack */
 161        if (__copy_from_user(&gprs_high, &sregs_ext->gprs_high,
 162                             sizeof(sregs_ext->gprs_high)))
 163                return -EFAULT;
 164        for (i = 0; i < NUM_GPRS; i++)
 165                *(__u32 *)&regs->gprs[i] = gprs_high[i];
 166
 167        /* Restore vector registers from signal stack */
 168        if (MACHINE_HAS_VX) {
 169                if (__copy_from_user(vxrs, &sregs_ext->vxrs_low,
 170                                     sizeof(sregs_ext->vxrs_low)) ||
 171                    __copy_from_user(current->thread.fpu.vxrs + __NUM_VXRS_LOW,
 172                                     &sregs_ext->vxrs_high,
 173                                     sizeof(sregs_ext->vxrs_high)))
 174                        return -EFAULT;
 175                for (i = 0; i < __NUM_VXRS_LOW; i++)
 176                        *((__u64 *)(current->thread.fpu.vxrs + i) + 1) = vxrs[i];
 177        }
 178        return 0;
 179}
 180
 181COMPAT_SYSCALL_DEFINE0(sigreturn)
 182{
 183        struct pt_regs *regs = task_pt_regs(current);
 184        sigframe32 __user *frame = (sigframe32 __user *)regs->gprs[15];
 185        sigset_t set;
 186
 187        if (get_compat_sigset(&set, (compat_sigset_t __user *)frame->sc.oldmask))
 188                goto badframe;
 189        set_current_blocked(&set);
 190        save_fpu_regs();
 191        if (restore_sigregs32(regs, &frame->sregs))
 192                goto badframe;
 193        if (restore_sigregs_ext32(regs, &frame->sregs_ext))
 194                goto badframe;
 195        load_sigregs();
 196        return regs->gprs[2];
 197badframe:
 198        force_sig(SIGSEGV);
 199        return 0;
 200}
 201
 202COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
 203{
 204        struct pt_regs *regs = task_pt_regs(current);
 205        rt_sigframe32 __user *frame = (rt_sigframe32 __user *)regs->gprs[15];
 206        sigset_t set;
 207
 208        if (get_compat_sigset(&set, &frame->uc.uc_sigmask))
 209                goto badframe;
 210        set_current_blocked(&set);
 211        if (compat_restore_altstack(&frame->uc.uc_stack))
 212                goto badframe;
 213        save_fpu_regs();
 214        if (restore_sigregs32(regs, &frame->uc.uc_mcontext))
 215                goto badframe;
 216        if (restore_sigregs_ext32(regs, &frame->uc.uc_mcontext_ext))
 217                goto badframe;
 218        load_sigregs();
 219        return regs->gprs[2];
 220badframe:
 221        force_sig(SIGSEGV);
 222        return 0;
 223}       
 224
 225/*
 226 * Set up a signal frame.
 227 */
 228
 229
 230/*
 231 * Determine which stack to use..
 232 */
 233static inline void __user *
 234get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
 235{
 236        unsigned long sp;
 237
 238        /* Default to using normal stack */
 239        sp = (unsigned long) A(regs->gprs[15]);
 240
 241        /* Overflow on alternate signal stack gives SIGSEGV. */
 242        if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
 243                return (void __user *) -1UL;
 244
 245        /* This is the X/Open sanctioned signal stack switching.  */
 246        if (ka->sa.sa_flags & SA_ONSTACK) {
 247                if (! sas_ss_flags(sp))
 248                        sp = current->sas_ss_sp + current->sas_ss_size;
 249        }
 250
 251        return (void __user *)((sp - frame_size) & -8ul);
 252}
 253
 254static int setup_frame32(struct ksignal *ksig, sigset_t *set,
 255                         struct pt_regs *regs)
 256{
 257        int sig = ksig->sig;
 258        sigframe32 __user *frame;
 259        unsigned long restorer;
 260        size_t frame_size;
 261
 262        /*
 263         * gprs_high are always present for 31-bit compat tasks.
 264         * The space for vector registers is only allocated if
 265         * the machine supports it
 266         */
 267        frame_size = sizeof(*frame) - sizeof(frame->sregs_ext.__reserved);
 268        if (!MACHINE_HAS_VX)
 269                frame_size -= sizeof(frame->sregs_ext.vxrs_low) +
 270                              sizeof(frame->sregs_ext.vxrs_high);
 271        frame = get_sigframe(&ksig->ka, regs, frame_size);
 272        if (frame == (void __user *) -1UL)
 273                return -EFAULT;
 274
 275        /* Set up backchain. */
 276        if (__put_user(regs->gprs[15], (unsigned int __user *) frame))
 277                return -EFAULT;
 278
 279        /* Create struct sigcontext32 on the signal stack */
 280        if (put_compat_sigset((compat_sigset_t __user *)frame->sc.oldmask,
 281                              set, sizeof(compat_sigset_t)))
 282                return -EFAULT;
 283        if (__put_user(ptr_to_compat(&frame->sregs), &frame->sc.sregs))
 284                return -EFAULT;
 285
 286        /* Store registers needed to create the signal frame */
 287        store_sigregs();
 288
 289        /* Create _sigregs32 on the signal stack */
 290        if (save_sigregs32(regs, &frame->sregs))
 291                return -EFAULT;
 292
 293        /* Place signal number on stack to allow backtrace from handler.  */
 294        if (__put_user(regs->gprs[2], (int __force __user *) &frame->signo))
 295                return -EFAULT;
 296
 297        /* Create _sigregs_ext32 on the signal stack */
 298        if (save_sigregs_ext32(regs, &frame->sregs_ext))
 299                return -EFAULT;
 300
 301        /* Set up to return from userspace.  If provided, use a stub
 302           already in userspace.  */
 303        if (ksig->ka.sa.sa_flags & SA_RESTORER) {
 304                restorer = (unsigned long __force)
 305                        ksig->ka.sa.sa_restorer | PSW32_ADDR_AMODE;
 306        } else {
 307                /* Signal frames without vectors registers are short ! */
 308                __u16 __user *svc = (void __user *) frame + frame_size - 2;
 309                if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn, svc))
 310                        return -EFAULT;
 311                restorer = (unsigned long __force) svc | PSW32_ADDR_AMODE;
 312        }
 313
 314        /* Set up registers for signal handler */
 315        regs->gprs[14] = restorer;
 316        regs->gprs[15] = (__force __u64) frame;
 317        /* Force 31 bit amode and default user address space control. */
 318        regs->psw.mask = PSW_MASK_BA |
 319                (PSW_USER_BITS & PSW_MASK_ASC) |
 320                (regs->psw.mask & ~PSW_MASK_ASC);
 321        regs->psw.addr = (__force __u64) ksig->ka.sa.sa_handler;
 322
 323        regs->gprs[2] = sig;
 324        regs->gprs[3] = (__force __u64) &frame->sc;
 325
 326        /* We forgot to include these in the sigcontext.
 327           To avoid breaking binary compatibility, they are passed as args. */
 328        if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
 329            sig == SIGTRAP || sig == SIGFPE) {
 330                /* set extra registers only for synchronous signals */
 331                regs->gprs[4] = regs->int_code & 127;
 332                regs->gprs[5] = regs->int_parm_long;
 333                regs->gprs[6] = current->thread.last_break;
 334        }
 335
 336        return 0;
 337}
 338
 339static int setup_rt_frame32(struct ksignal *ksig, sigset_t *set,
 340                            struct pt_regs *regs)
 341{
 342        rt_sigframe32 __user *frame;
 343        unsigned long restorer;
 344        size_t frame_size;
 345        u32 uc_flags;
 346
 347        frame_size = sizeof(*frame) -
 348                     sizeof(frame->uc.uc_mcontext_ext.__reserved);
 349        /*
 350         * gprs_high are always present for 31-bit compat tasks.
 351         * The space for vector registers is only allocated if
 352         * the machine supports it
 353         */
 354        uc_flags = UC_GPRS_HIGH;
 355        if (MACHINE_HAS_VX) {
 356                uc_flags |= UC_VXRS;
 357        } else
 358                frame_size -= sizeof(frame->uc.uc_mcontext_ext.vxrs_low) +
 359                              sizeof(frame->uc.uc_mcontext_ext.vxrs_high);
 360        frame = get_sigframe(&ksig->ka, regs, frame_size);
 361        if (frame == (void __user *) -1UL)
 362                return -EFAULT;
 363
 364        /* Set up backchain. */
 365        if (__put_user(regs->gprs[15], (unsigned int __force __user *) frame))
 366                return -EFAULT;
 367
 368        /* Set up to return from userspace.  If provided, use a stub
 369           already in userspace.  */
 370        if (ksig->ka.sa.sa_flags & SA_RESTORER) {
 371                restorer = (unsigned long __force)
 372                        ksig->ka.sa.sa_restorer | PSW32_ADDR_AMODE;
 373        } else {
 374                __u16 __user *svc = &frame->svc_insn;
 375                if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn, svc))
 376                        return -EFAULT;
 377                restorer = (unsigned long __force) svc | PSW32_ADDR_AMODE;
 378        }
 379
 380        /* Create siginfo on the signal stack */
 381        if (copy_siginfo_to_user32(&frame->info, &ksig->info))
 382                return -EFAULT;
 383
 384        /* Store registers needed to create the signal frame */
 385        store_sigregs();
 386
 387        /* Create ucontext on the signal stack. */
 388        if (__put_user(uc_flags, &frame->uc.uc_flags) ||
 389            __put_user(0, &frame->uc.uc_link) ||
 390            __compat_save_altstack(&frame->uc.uc_stack, regs->gprs[15]) ||
 391            save_sigregs32(regs, &frame->uc.uc_mcontext) ||
 392            put_compat_sigset(&frame->uc.uc_sigmask, set, sizeof(compat_sigset_t)) ||
 393            save_sigregs_ext32(regs, &frame->uc.uc_mcontext_ext))
 394                return -EFAULT;
 395
 396        /* Set up registers for signal handler */
 397        regs->gprs[14] = restorer;
 398        regs->gprs[15] = (__force __u64) frame;
 399        /* Force 31 bit amode and default user address space control. */
 400        regs->psw.mask = PSW_MASK_BA |
 401                (PSW_USER_BITS & PSW_MASK_ASC) |
 402                (regs->psw.mask & ~PSW_MASK_ASC);
 403        regs->psw.addr = (__u64 __force) ksig->ka.sa.sa_handler;
 404
 405        regs->gprs[2] = ksig->sig;
 406        regs->gprs[3] = (__force __u64) &frame->info;
 407        regs->gprs[4] = (__force __u64) &frame->uc;
 408        regs->gprs[5] = current->thread.last_break;
 409        return 0;
 410}
 411
 412/*
 413 * OK, we're invoking a handler
 414 */     
 415
 416void handle_signal32(struct ksignal *ksig, sigset_t *oldset,
 417                     struct pt_regs *regs)
 418{
 419        int ret;
 420
 421        /* Set up the stack frame */
 422        if (ksig->ka.sa.sa_flags & SA_SIGINFO)
 423                ret = setup_rt_frame32(ksig, oldset, regs);
 424        else
 425                ret = setup_frame32(ksig, oldset, regs);
 426
 427        signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLE_STEP));
 428}
 429
 430