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/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
  30 struct 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
  37 struct 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
  45 struct 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
  52 static 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
  85 static 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
 114 static 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
 154 asmlinkage 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
 189 badframe:
 190         force_sig(SIGSEGV);
 191 }
 192
 193 static 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  */
 243 struct 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
 256 asmlinkage 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
 288 badframe:
 289         force_sig(SIGSEGV);
 290 }