linux/arch/mips/kernel/signal_o32.c
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   1/*
   2 * This file is subject to the terms and conditions of the GNU General Public
   3 * License.  See the file "COPYING" in the main directory of this archive
   4 * for more details.
   5 *
   6 * Copyright (C) 1991, 1992  Linus Torvalds
   7 * Copyright (C) 1994 - 2000, 2006  Ralf Baechle
   8 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
   9 * Copyright (C) 2016, Imagination Technologies Ltd.
  10 */
  11#include <linux/compiler.h>
  12#include <linux/errno.h>
  13#include <linux/signal.h>
  14#include <linux/sched/signal.h>
  15#include <linux/uaccess.h>
  16
  17#include <asm/abi.h>
  18#include <asm/compat-signal.h>
  19#include <asm/dsp.h>
  20#include <asm/sim.h>
  21#include <asm/unistd.h>
  22
  23#include "signal-common.h"
  24
  25/*
  26 * Including <asm/unistd.h> would give use the 64-bit syscall numbers ...
  27 */
  28#define __NR_O32_restart_syscall        4253
  29
  30struct sigframe32 {
  31        u32 sf_ass[4];          /* argument save space for o32 */
  32        u32 sf_pad[2];          /* Was: signal trampoline */
  33        struct sigcontext32 sf_sc;
  34        compat_sigset_t sf_mask;
  35};
  36
  37struct ucontext32 {
  38        u32                 uc_flags;
  39        s32                 uc_link;
  40        compat_stack_t      uc_stack;
  41        struct sigcontext32 uc_mcontext;
  42        compat_sigset_t     uc_sigmask;   /* mask last for extensibility */
  43};
  44
  45struct rt_sigframe32 {
  46        u32 rs_ass[4];                  /* argument save space for o32 */
  47        u32 rs_pad[2];                  /* Was: signal trampoline */
  48        compat_siginfo_t rs_info;
  49        struct ucontext32 rs_uc;
  50};
  51
  52static int setup_sigcontext32(struct pt_regs *regs,
  53                              struct sigcontext32 __user *sc)
  54{
  55        int err = 0;
  56        int i;
  57
  58        err |= __put_user(regs->cp0_epc, &sc->sc_pc);
  59
  60        err |= __put_user(0, &sc->sc_regs[0]);
  61        for (i = 1; i < 32; i++)
  62                err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
  63
  64        err |= __put_user(regs->hi, &sc->sc_mdhi);
  65        err |= __put_user(regs->lo, &sc->sc_mdlo);
  66        if (cpu_has_dsp) {
  67                err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
  68                err |= __put_user(mfhi1(), &sc->sc_hi1);
  69                err |= __put_user(mflo1(), &sc->sc_lo1);
  70                err |= __put_user(mfhi2(), &sc->sc_hi2);
  71                err |= __put_user(mflo2(), &sc->sc_lo2);
  72                err |= __put_user(mfhi3(), &sc->sc_hi3);
  73                err |= __put_user(mflo3(), &sc->sc_lo3);
  74        }
  75
  76        /*
  77         * Save FPU state to signal context.  Signal handler
  78         * will "inherit" current FPU state.
  79         */
  80        err |= protected_save_fp_context(sc);
  81
  82        return err;
  83}
  84
  85static int restore_sigcontext32(struct pt_regs *regs,
  86                                struct sigcontext32 __user *sc)
  87{
  88        int err = 0;
  89        s32 treg;
  90        int i;
  91
  92        /* Always make any pending restarted system calls return -EINTR */
  93        current->restart_block.fn = do_no_restart_syscall;
  94
  95        err |= __get_user(regs->cp0_epc, &sc->sc_pc);
  96        err |= __get_user(regs->hi, &sc->sc_mdhi);
  97        err |= __get_user(regs->lo, &sc->sc_mdlo);
  98        if (cpu_has_dsp) {
  99                err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
 100                err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
 101                err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
 102                err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
 103                err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
 104                err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
 105                err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
 106        }
 107
 108        for (i = 1; i < 32; i++)
 109                err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
 110
 111        return err ?: protected_restore_fp_context(sc);
 112}
 113
 114static int setup_frame_32(void *sig_return, struct ksignal *ksig,
 115                          struct pt_regs *regs, sigset_t *set)
 116{
 117        struct sigframe32 __user *frame;
 118        int err = 0;
 119
 120        frame = get_sigframe(ksig, regs, sizeof(*frame));
 121        if (!access_ok(frame, sizeof (*frame)))
 122                return -EFAULT;
 123
 124        err |= setup_sigcontext32(regs, &frame->sf_sc);
 125        err |= __copy_conv_sigset_to_user(&frame->sf_mask, set);
 126
 127        if (err)
 128                return -EFAULT;
 129
 130        /*
 131         * Arguments to signal handler:
 132         *
 133         *   a0 = signal number
 134         *   a1 = 0 (should be cause)
 135         *   a2 = pointer to struct sigcontext
 136         *
 137         * $25 and c0_epc point to the signal handler, $29 points to the
 138         * struct sigframe.
 139         */
 140        regs->regs[ 4] = ksig->sig;
 141        regs->regs[ 5] = 0;
 142        regs->regs[ 6] = (unsigned long) &frame->sf_sc;
 143        regs->regs[29] = (unsigned long) frame;
 144        regs->regs[31] = (unsigned long) sig_return;
 145        regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
 146
 147        DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 148               current->comm, current->pid,
 149               frame, regs->cp0_epc, regs->regs[31]);
 150
 151        return 0;
 152}
 153
 154asmlinkage void sys32_rt_sigreturn(void)
 155{
 156        struct rt_sigframe32 __user *frame;
 157        struct pt_regs *regs;
 158        sigset_t set;
 159        int sig;
 160
 161        regs = current_pt_regs();
 162        frame = (struct rt_sigframe32 __user *)regs->regs[29];
 163        if (!access_ok(frame, sizeof(*frame)))
 164                goto badframe;
 165        if (__copy_conv_sigset_from_user(&set, &frame->rs_uc.uc_sigmask))
 166                goto badframe;
 167
 168        set_current_blocked(&set);
 169
 170        sig = restore_sigcontext32(regs, &frame->rs_uc.uc_mcontext);
 171        if (sig < 0)
 172                goto badframe;
 173        else if (sig)
 174                force_sig(sig);
 175
 176        if (compat_restore_altstack(&frame->rs_uc.uc_stack))
 177                goto badframe;
 178
 179        /*
 180         * Don't let your children do this ...
 181         */
 182        __asm__ __volatile__(
 183                "move\t$29, %0\n\t"
 184                "j\tsyscall_exit"
 185                : /* no outputs */
 186                : "r" (regs));
 187        /* Unreached */
 188
 189badframe:
 190        force_sig(SIGSEGV);
 191}
 192
 193static int setup_rt_frame_32(void *sig_return, struct ksignal *ksig,
 194                             struct pt_regs *regs, sigset_t *set)
 195{
 196        struct rt_sigframe32 __user *frame;
 197        int err = 0;
 198
 199        frame = get_sigframe(ksig, regs, sizeof(*frame));
 200        if (!access_ok(frame, sizeof (*frame)))
 201                return -EFAULT;
 202
 203        /* Convert (siginfo_t -> compat_siginfo_t) and copy to user. */
 204        err |= copy_siginfo_to_user32(&frame->rs_info, &ksig->info);
 205
 206        /* Create the ucontext.  */
 207        err |= __put_user(0, &frame->rs_uc.uc_flags);
 208        err |= __put_user(0, &frame->rs_uc.uc_link);
 209        err |= __compat_save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
 210        err |= setup_sigcontext32(regs, &frame->rs_uc.uc_mcontext);
 211        err |= __copy_conv_sigset_to_user(&frame->rs_uc.uc_sigmask, set);
 212
 213        if (err)
 214                return -EFAULT;
 215
 216        /*
 217         * Arguments to signal handler:
 218         *
 219         *   a0 = signal number
 220         *   a1 = 0 (should be cause)
 221         *   a2 = pointer to ucontext
 222         *
 223         * $25 and c0_epc point to the signal handler, $29 points to
 224         * the struct rt_sigframe32.
 225         */
 226        regs->regs[ 4] = ksig->sig;
 227        regs->regs[ 5] = (unsigned long) &frame->rs_info;
 228        regs->regs[ 6] = (unsigned long) &frame->rs_uc;
 229        regs->regs[29] = (unsigned long) frame;
 230        regs->regs[31] = (unsigned long) sig_return;
 231        regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
 232
 233        DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 234               current->comm, current->pid,
 235               frame, regs->cp0_epc, regs->regs[31]);
 236
 237        return 0;
 238}
 239
 240/*
 241 * o32 compatibility on 64-bit kernels, without DSP ASE
 242 */
 243struct mips_abi mips_abi_32 = {
 244        .setup_frame    = setup_frame_32,
 245        .setup_rt_frame = setup_rt_frame_32,
 246        .restart        = __NR_O32_restart_syscall,
 247
 248        .off_sc_fpregs = offsetof(struct sigcontext32, sc_fpregs),
 249        .off_sc_fpc_csr = offsetof(struct sigcontext32, sc_fpc_csr),
 250        .off_sc_used_math = offsetof(struct sigcontext32, sc_used_math),
 251
 252        .vdso           = &vdso_image_o32,
 253};
 254
 255
 256asmlinkage void sys32_sigreturn(void)
 257{
 258        struct sigframe32 __user *frame;
 259        struct pt_regs *regs;
 260        sigset_t blocked;
 261        int sig;
 262
 263        regs = current_pt_regs();
 264        frame = (struct sigframe32 __user *)regs->regs[29];
 265        if (!access_ok(frame, sizeof(*frame)))
 266                goto badframe;
 267        if (__copy_conv_sigset_from_user(&blocked, &frame->sf_mask))
 268                goto badframe;
 269
 270        set_current_blocked(&blocked);
 271
 272        sig = restore_sigcontext32(regs, &frame->sf_sc);
 273        if (sig < 0)
 274                goto badframe;
 275        else if (sig)
 276                force_sig(sig);
 277
 278        /*
 279         * Don't let your children do this ...
 280         */
 281        __asm__ __volatile__(
 282                "move\t$29, %0\n\t"
 283                "j\tsyscall_exit"
 284                : /* no outputs */
 285                : "r" (regs));
 286        /* Unreached */
 287
 288badframe:
 289        force_sig(SIGSEGV);
 290}
 291