arch/mips/kernel/signal_n32.c

   1 /*
   2  * Copyright (C) 2003 Broadcom Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/mm.h>
  20 #include <linux/smp.h>
  21 #include <linux/smp_lock.h>
  22 #include <linux/kernel.h>
  23 #include <linux/signal.h>
  24 #include <linux/errno.h>
  25 #include <linux/wait.h>
  26 #include <linux/ptrace.h>
  27 #include <linux/unistd.h>
  28 #include <linux/compat.h>
  29
  30 #include <asm/asm.h>
  31 #include <asm/bitops.h>
  32 #include <asm/cacheflush.h>
  33 #include <asm/sim.h>
  34 #include <asm/uaccess.h>
  35 #include <asm/ucontext.h>
  36 #include <asm/system.h>
  37 #include <asm/fpu.h>
  38
  39 /*
  40  * Including <asm/unistd.h would give use the 64-bit syscall numbers ...
  41  */
  42 #define __NR_N32_rt_sigreturn           6211
  43 #define __NR_N32_restart_syscall        6214
  44
  45 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  46
  47 /* IRIX compatible stack_t  */
  48 typedef struct sigaltstack32 {
  49         s32 ss_sp;
  50         compat_size_t ss_size;
  51         int ss_flags;
  52 } stack32_t;
  53
  54 struct ucontextn32 {
  55         u32                 uc_flags;
  56         s32                 uc_link;
  57         stack32_t           uc_stack;
  58         struct sigcontext   uc_mcontext;
  59         sigset_t            uc_sigmask;   /* mask last for extensibility */
  60 };
  61
  62 struct rt_sigframe_n32 {
  63         u32 rs_ass[4];                  /* argument save space for o32 */
  64         u32 rs_code[2];                 /* signal trampoline */
  65         struct siginfo rs_info;
  66         struct ucontextn32 rs_uc;
  67 };
  68
  69 extern asmlinkage int restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc);
  70 extern int inline setup_sigcontext(struct pt_regs *regs, struct sigcontext *sc);
  71
  72 asmlinkage void sysn32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
  73 {
  74         struct rt_sigframe_n32 *frame;
  75         sigset_t set;
  76         stack_t st;
  77         s32 sp;
  78
  79         frame = (struct rt_sigframe_n32 *) regs.regs[29];
  80         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
  81                 goto badframe;
  82         if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
  83                 goto badframe;
  84
  85         sigdelsetmask(&set, ~_BLOCKABLE);
  86         spin_lock_irq(&current->sighand->siglock);
  87         current->blocked = set;
  88         recalc_sigpending();
  89         spin_unlock_irq(&current->sighand->siglock);
  90
  91         if (restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext))
  92                 goto badframe;
  93
  94         /* The ucontext contains a stack32_t, so we must convert!  */
  95         if (__get_user(sp, &frame->rs_uc.uc_stack.ss_sp))
  96                 goto badframe;
  97         st.ss_size = (long) sp;
  98         if (__get_user(st.ss_size, &frame->rs_uc.uc_stack.ss_size))
  99                 goto badframe;
 100         if (__get_user(st.ss_flags, &frame->rs_uc.uc_stack.ss_flags))
 101                 goto badframe;
 102
 103         /* It is more difficult to avoid calling this function than to
 104            call it and ignore errors.  */
 105         do_sigaltstack(&st, NULL, regs.regs[29]);
 106
 107         /*
 108          * Don't let your children do this ...
 109          */
 110         __asm__ __volatile__(
 111                 "move\t$29, %0\n\t"
 112                 "j\tsyscall_exit"
 113                 :/* no outputs */
 114                 :"r" (&regs));
 115         /* Unreached */
 116
 117 badframe:
 118         force_sig(SIGSEGV, current);
 119 }
 120
 121 /*
 122  * Determine which stack to use..
 123  */
 124 static inline void *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
 125         size_t frame_size)
 126 {
 127         unsigned long sp;
 128
 129         /* Default to using normal stack */
 130         sp = regs->regs[29];
 131
 132         /*
 133          * FPU emulator may have it's own trampoline active just
 134          * above the user stack, 16-bytes before the next lowest
 135          * 16 byte boundary.  Try to avoid trashing it.
 136          */
 137         sp -= 32;
 138
 139         /* This is the X/Open sanctioned signal stack switching.  */
 140         if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags (sp) == 0))
 141                 sp = current->sas_ss_sp + current->sas_ss_size;
 142
 143         return (void *)((sp - frame_size) & ALMASK);
 144 }
 145
 146 void setup_rt_frame_n32(struct k_sigaction * ka,
 147         struct pt_regs *regs, int signr, sigset_t *set, siginfo_t *info)
 148 {
 149         struct rt_sigframe_n32 *frame;
 150         int err = 0;
 151         s32 sp;
 152
 153         frame = get_sigframe(ka, regs, sizeof(*frame));
 154         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 155                 goto give_sigsegv;
 156
 157         /*
 158          * Set up the return code ...
 159          *
 160          *         li      v0, __NR_rt_sigreturn
 161          *         syscall
 162          */
 163         err |= __put_user(0x24020000 + __NR_N32_rt_sigreturn, frame->rs_code + 0);
 164         err |= __put_user(0x0000000c                    , frame->rs_code + 1);
 165         flush_cache_sigtramp((unsigned long) frame->rs_code);
 166
 167         /* Create siginfo.  */
 168         err |= copy_siginfo_to_user(&frame->rs_info, info);
 169
 170         /* Create the ucontext.  */
 171         err |= __put_user(0, &frame->rs_uc.uc_flags);
 172         err |= __put_user(0, &frame->rs_uc.uc_link);
 173         sp = (int) (long) current->sas_ss_sp;
 174         err |= __put_user(sp,
 175                           &frame->rs_uc.uc_stack.ss_sp);
 176         err |= __put_user(sas_ss_flags(regs->regs[29]),
 177                           &frame->rs_uc.uc_stack.ss_flags);
 178         err |= __put_user(current->sas_ss_size,
 179                           &frame->rs_uc.uc_stack.ss_size);
 180         err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 181         err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
 182
 183         if (err)
 184                 goto give_sigsegv;
 185
 186         /*
 187          * Arguments to signal handler:
 188          *
 189          *   a0 = signal number
 190          *   a1 = 0 (should be cause)
 191          *   a2 = pointer to ucontext
 192          *
 193          * $25 and c0_epc point to the signal handler, $29 points to
 194          * the struct rt_sigframe.
 195          */
 196         regs->regs[ 4] = signr;
 197         regs->regs[ 5] = (unsigned long) &frame->rs_info;
 198         regs->regs[ 6] = (unsigned long) &frame->rs_uc;
 199         regs->regs[29] = (unsigned long) frame;
 200         regs->regs[31] = (unsigned long) frame->rs_code;
 201         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
 202
 203 #if DEBUG_SIG
 204         printk("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%p\n",
 205                current->comm, current->pid,
 206                frame, regs->cp0_epc, regs->regs[31]);
 207 #endif
 208         return;
 209
 210 give_sigsegv:
 211         force_sigsegv(signr, current);
 212 }