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        return 0;
 122}
 123
 124static int save_sigregs_ext32(struct pt_regs *regs,
 125                              _sigregs_ext32 __user *sregs_ext)
 126{
 127        __u32 gprs_high[NUM_GPRS];
 128        __u64 vxrs[__NUM_VXRS_LOW];
 129        int i;
 130
 131        /* Save high gprs to signal stack */
 132        for (i = 0; i < NUM_GPRS; i++)
 133                gprs_high[i] = regs->gprs[i] >> 32;
 134        if (__copy_to_user(&sregs_ext->gprs_high, &gprs_high,
 135                           sizeof(sregs_ext->gprs_high)))
 136                return -EFAULT;
 137
 138        /* Save vector registers to signal stack */
 139        if (MACHINE_HAS_VX) {
 140                for (i = 0; i < __NUM_VXRS_LOW; i++)
 141                        vxrs[i] = *((__u64 *)(current->thread.fpu.vxrs + i) + 1);
 142                if (__copy_to_user(&sregs_ext->vxrs_low, vxrs,
 143                                   sizeof(sregs_ext->vxrs_low)) ||
 144                    __copy_to_user(&sregs_ext->vxrs_high,
 145                                   current->thread.fpu.vxrs + __NUM_VXRS_LOW,
 146                                   sizeof(sregs_ext->vxrs_high)))
 147                        return -EFAULT;
 148        }
 149        return 0;
 150}
 151
 152static int restore_sigregs_ext32(struct pt_regs *regs,
 153                                 _sigregs_ext32 __user *sregs_ext)
 154{
 155        __u32 gprs_high[NUM_GPRS];
 156        __u64 vxrs[__NUM_VXRS_LOW];
 157        int i;
 158
 159        /* Restore high gprs from signal stack */
 160        if (__copy_from_user(&gprs_high, &sregs_ext->gprs_high,
 161                             sizeof(sregs_ext->gprs_high)))
 162                return -EFAULT;
 163        for (i = 0; i < NUM_GPRS; i++)
 164                *(__u32 *)&regs->gprs[i] = gprs_high[i];
 165
 166        /* Restore vector registers from signal stack */
 167        if (MACHINE_HAS_VX) {
 168                if (__copy_from_user(vxrs, &sregs_ext->vxrs_low,
 169                                     sizeof(sregs_ext->vxrs_low)) ||
 170                    __copy_from_user(current->thread.fpu.vxrs + __NUM_VXRS_LOW,
 171                                     &sregs_ext->vxrs_high,
 172                                     sizeof(sregs_ext->vxrs_high)))
 173                        return -EFAULT;
 174                for (i = 0; i < __NUM_VXRS_LOW; i++)
 175                        *((__u64 *)(current->thread.fpu.vxrs + i) + 1) = vxrs[i];
 176        }
 177        return 0;
 178}
 179
 180COMPAT_SYSCALL_DEFINE0(sigreturn)
 181{
 182        struct pt_regs *regs = task_pt_regs(current);
 183        sigframe32 __user *frame = (sigframe32 __user *)regs->gprs[15];
 184        sigset_t set;
 185
 186        if (get_compat_sigset(&set, (compat_sigset_t __user *)frame->sc.oldmask))
 187                goto badframe;
 188        set_current_blocked(&set);
 189        save_fpu_regs();
 190        if (restore_sigregs32(regs, &frame->sregs))
 191                goto badframe;
 192        if (restore_sigregs_ext32(regs, &frame->sregs_ext))
 193                goto badframe;
 194        load_sigregs();
 195        return regs->gprs[2];
 196badframe:
 197        force_sig(SIGSEGV);
 198        return 0;
 199}
 200
 201COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
 202{
 203        struct pt_regs *regs = task_pt_regs(current);
 204        rt_sigframe32 __user *frame = (rt_sigframe32 __user *)regs->gprs[15];
 205        sigset_t set;
 206
 207        if (get_compat_sigset(&set, &frame->uc.uc_sigmask))
 208                goto badframe;
 209        set_current_blocked(&set);
 210        if (compat_restore_altstack(&frame->uc.uc_stack))
 211                goto badframe;
 212        save_fpu_regs();
 213        if (restore_sigregs32(regs, &frame->uc.uc_mcontext))
 214                goto badframe;
 215        if (restore_sigregs_ext32(regs, &frame->uc.uc_mcontext_ext))
 216                goto badframe;
 217        load_sigregs();
 218        return regs->gprs[2];
 219badframe:
 220        force_sig(SIGSEGV);
 221        return 0;
 222}       
 223
 224/*
 225 * Set up a signal frame.
 226 */
 227
 228
 229/*
 230 * Determine which stack to use..
 231 */
 232static inline void __user *
 233get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
 234{
 235        unsigned long sp;
 236
 237        /* Default to using normal stack */
 238        sp = (unsigned long) A(regs->gprs[15]);
 239
 240        /* Overflow on alternate signal stack gives SIGSEGV. */
 241        if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
 242                return (void __user *) -1UL;
 243
 244        /* This is the X/Open sanctioned signal stack switching.  */
 245        if (ka->sa.sa_flags & SA_ONSTACK) {
 246                if (! sas_ss_flags(sp))
 247                        sp = current->sas_ss_sp + current->sas_ss_size;
 248        }
 249
 250        return (void __user *)((sp - frame_size) & -8ul);
 251}
 252
 253static int setup_frame32(struct ksignal *ksig, sigset_t *set,
 254                         struct pt_regs *regs)
 255{
 256        int sig = ksig->sig;
 257        sigframe32 __user *frame;
 258        unsigned long restorer;
 259        size_t frame_size;
 260
 261        /*
 262         * gprs_high are always present for 31-bit compat tasks.
 263         * The space for vector registers is only allocated if
 264         * the machine supports it
 265         */
 266        frame_size = sizeof(*frame) - sizeof(frame->sregs_ext.__reserved);
 267        if (!MACHINE_HAS_VX)
 268                frame_size -= sizeof(frame->sregs_ext.vxrs_low) +
 269                              sizeof(frame->sregs_ext.vxrs_high);
 270        frame = get_sigframe(&ksig->ka, regs, frame_size);
 271        if (frame == (void __user *) -1UL)
 272                return -EFAULT;
 273
 274        /* Set up backchain. */
 275        if (__put_user(regs->gprs[15], (unsigned int __user *) frame))
 276                return -EFAULT;
 277
 278        /* Create struct sigcontext32 on the signal stack */
 279        if (put_compat_sigset((compat_sigset_t __user *)frame->sc.oldmask,
 280                              set, sizeof(compat_sigset_t)))
 281                return -EFAULT;
 282        if (__put_user(ptr_to_compat(&frame->sregs), &frame->sc.sregs))
 283                return -EFAULT;
 284
 285        /* Store registers needed to create the signal frame */
 286        store_sigregs();
 287
 288        /* Create _sigregs32 on the signal stack */
 289        if (save_sigregs32(regs, &frame->sregs))
 290                return -EFAULT;
 291
 292        /* Place signal number on stack to allow backtrace from handler.  */
 293        if (__put_user(regs->gprs[2], (int __force __user *) &frame->signo))
 294                return -EFAULT;
 295
 296        /* Create _sigregs_ext32 on the signal stack */
 297        if (save_sigregs_ext32(regs, &frame->sregs_ext))
 298                return -EFAULT;
 299
 300        /* Set up to return from userspace.  If provided, use a stub
 301           already in userspace.  */
 302        if (ksig->ka.sa.sa_flags & SA_RESTORER) {
 303                restorer = (unsigned long __force)
 304                        ksig->ka.sa.sa_restorer | PSW32_ADDR_AMODE;
 305        } else {
 306                /* Signal frames without vectors registers are short ! */
 307                __u16 __user *svc = (void __user *) frame + frame_size - 2;
 308                if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn, svc))
 309                        return -EFAULT;
 310                restorer = (unsigned long __force) svc | PSW32_ADDR_AMODE;
 311        }
 312
 313        /* Set up registers for signal handler */
 314        regs->gprs[14] = restorer;
 315        regs->gprs[15] = (__force __u64) frame;
 316        /* Force 31 bit amode and default user address space control. */
 317        regs->psw.mask = PSW_MASK_BA |
 318                (PSW_USER_BITS & PSW_MASK_ASC) |
 319                (regs->psw.mask & ~PSW_MASK_ASC);
 320        regs->psw.addr = (__force __u64) ksig->ka.sa.sa_handler;
 321
 322        regs->gprs[2] = sig;
 323        regs->gprs[3] = (__force __u64) &frame->sc;
 324
 325        /* We forgot to include these in the sigcontext.
 326           To avoid breaking binary compatibility, they are passed as args. */
 327        if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
 328            sig == SIGTRAP || sig == SIGFPE) {
 329                /* set extra registers only for synchronous signals */
 330                regs->gprs[4] = regs->int_code & 127;
 331                regs->gprs[5] = regs->int_parm_long;
 332                regs->gprs[6] = current->thread.last_break;
 333        }
 334
 335        return 0;
 336}
 337
 338static int setup_rt_frame32(struct ksignal *ksig, sigset_t *set,
 339                            struct pt_regs *regs)
 340{
 341        rt_sigframe32 __user *frame;
 342        unsigned long restorer;
 343        size_t frame_size;
 344        u32 uc_flags;
 345
 346        frame_size = sizeof(*frame) -
 347                     sizeof(frame->uc.uc_mcontext_ext.__reserved);
 348        /*
 349         * gprs_high are always present for 31-bit compat tasks.
 350         * The space for vector registers is only allocated if
 351         * the machine supports it
 352         */
 353        uc_flags = UC_GPRS_HIGH;
 354        if (MACHINE_HAS_VX) {
 355                uc_flags |= UC_VXRS;
 356        } else
 357                frame_size -= sizeof(frame->uc.uc_mcontext_ext.vxrs_low) +
 358                              sizeof(frame->uc.uc_mcontext_ext.vxrs_high);
 359        frame = get_sigframe(&ksig->ka, regs, frame_size);
 360        if (frame == (void __user *) -1UL)
 361                return -EFAULT;
 362
 363        /* Set up backchain. */
 364        if (__put_user(regs->gprs[15], (unsigned int __force __user *) frame))
 365                return -EFAULT;
 366
 367        /* Set up to return from userspace.  If provided, use a stub
 368           already in userspace.  */
 369        if (ksig->ka.sa.sa_flags & SA_RESTORER) {
 370                restorer = (unsigned long __force)
 371                        ksig->ka.sa.sa_restorer | PSW32_ADDR_AMODE;
 372        } else {
 373                __u16 __user *svc = &frame->svc_insn;
 374                if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn, svc))
 375                        return -EFAULT;
 376                restorer = (unsigned long __force) svc | PSW32_ADDR_AMODE;
 377        }
 378
 379        /* Create siginfo on the signal stack */
 380        if (copy_siginfo_to_user32(&frame->info, &ksig->info))
 381                return -EFAULT;
 382
 383        /* Store registers needed to create the signal frame */
 384        store_sigregs();
 385
 386        /* Create ucontext on the signal stack. */
 387        if (__put_user(uc_flags, &frame->uc.uc_flags) ||
 388            __put_user(0, &frame->uc.uc_link) ||
 389            __compat_save_altstack(&frame->uc.uc_stack, regs->gprs[15]) ||
 390            save_sigregs32(regs, &frame->uc.uc_mcontext) ||
 391            put_compat_sigset(&frame->uc.uc_sigmask, set, sizeof(compat_sigset_t)) ||
 392            save_sigregs_ext32(regs, &frame->uc.uc_mcontext_ext))
 393                return -EFAULT;
 394
 395        /* Set up registers for signal handler */
 396        regs->gprs[14] = restorer;
 397        regs->gprs[15] = (__force __u64) frame;
 398        /* Force 31 bit amode and default user address space control. */
 399        regs->psw.mask = PSW_MASK_BA |
 400                (PSW_USER_BITS & PSW_MASK_ASC) |
 401                (regs->psw.mask & ~PSW_MASK_ASC);
 402        regs->psw.addr = (__u64 __force) ksig->ka.sa.sa_handler;
 403
 404        regs->gprs[2] = ksig->sig;
 405        regs->gprs[3] = (__force __u64) &frame->info;
 406        regs->gprs[4] = (__force __u64) &frame->uc;
 407        regs->gprs[5] = current->thread.last_break;
 408        return 0;
 409}
 410
 411/*
 412 * OK, we're invoking a handler
 413 */     
 414
 415void handle_signal32(struct ksignal *ksig, sigset_t *oldset,
 416                     struct pt_regs *regs)
 417{
 418        int ret;
 419
 420        /* Set up the stack frame */
 421        if (ksig->ka.sa.sa_flags & SA_SIGINFO)
 422                ret = setup_rt_frame32(ksig, oldset, regs);
 423        else
 424                ret = setup_frame32(ksig, oldset, regs);
 425
 426        signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLE_STEP));
 427}
 428
 429