arch/mips/kernel/signal_o32.c

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