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 #include <linux/bitops.h>
  30
  31 #include <asm/asm.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 #include <asm/cpu-features.h>
  39
  40 #include "signal-common.h"
  41
  42 /*
  43  * Including <asm/unistd.h> would give use the 64-bit syscall numbers ...
  44  */
  45 #define __NR_N32_rt_sigreturn           6211
  46 #define __NR_N32_restart_syscall        6214
  47
  48 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  49
  50 /* IRIX compatible stack_t  */
  51 typedef struct sigaltstack32 {
  52         s32 ss_sp;
  53         compat_size_t ss_size;
  54         int ss_flags;
  55 } stack32_t;
  56
  57 struct ucontextn32 {
  58         u32                 uc_flags;
  59         s32                 uc_link;
  60         stack32_t           uc_stack;
  61         struct sigcontext   uc_mcontext;
  62         sigset_t            uc_sigmask;   /* mask last for extensibility */
  63 };
  64
  65 #if PLAT_TRAMPOLINE_STUFF_LINE
  66 #define __tramp __attribute__((aligned(PLAT_TRAMPOLINE_STUFF_LINE)))
  67 #else
  68 #define __tramp
  69 #endif
  70
  71 struct rt_sigframe_n32 {
  72         u32 rs_ass[4];                  /* argument save space for o32 */
  73         u32 rs_code[2] __tramp;         /* signal trampoline */
  74         struct siginfo rs_info __tramp;
  75         struct ucontextn32 rs_uc;
  76 };
  77
  78 save_static_function(sysn32_rt_sigreturn);
  79 __attribute_used__ noinline static void
  80 _sysn32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
  81 {
  82         struct rt_sigframe_n32 *frame;
  83         sigset_t set;
  84         stack_t st;
  85         s32 sp;
  86
  87         frame = (struct rt_sigframe_n32 *) regs.regs[29];
  88         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
  89                 goto badframe;
  90         if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
  91                 goto badframe;
  92
  93         sigdelsetmask(&set, ~_BLOCKABLE);
  94         spin_lock_irq(&current->sighand->siglock);
  95         current->blocked = set;
  96         recalc_sigpending();
  97         spin_unlock_irq(&current->sighand->siglock);
  98
  99         if (restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext))
 100                 goto badframe;
 101
 102         /* The ucontext contains a stack32_t, so we must convert!  */
 103         if (__get_user(sp, &frame->rs_uc.uc_stack.ss_sp))
 104                 goto badframe;
 105         st.ss_size = (long) sp;
 106         if (__get_user(st.ss_size, &frame->rs_uc.uc_stack.ss_size))
 107                 goto badframe;
 108         if (__get_user(st.ss_flags, &frame->rs_uc.uc_stack.ss_flags))
 109                 goto badframe;
 110
 111         /* It is more difficult to avoid calling this function than to
 112            call it and ignore errors.  */
 113         do_sigaltstack(&st, NULL, regs.regs[29]);
 114
 115         /*
 116          * Don't let your children do this ...
 117          */
 118         __asm__ __volatile__(
 119                 "move\t$29, %0\n\t"
 120                 "j\tsyscall_exit"
 121                 :/* no outputs */
 122                 :"r" (&regs));
 123         /* Unreached */
 124
 125 badframe:
 126         force_sig(SIGSEGV, current);
 127 }
 128
 129 void setup_rt_frame_n32(struct k_sigaction * ka,
 130         struct pt_regs *regs, int signr, sigset_t *set, siginfo_t *info)
 131 {
 132         struct rt_sigframe_n32 *frame;
 133         int err = 0;
 134         s32 sp;
 135
 136         frame = get_sigframe(ka, regs, sizeof(*frame));
 137         if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
 138                 goto give_sigsegv;
 139
 140         /*
 141          * Set up the return code ...
 142          *
 143          *         li      v0, __NR_rt_sigreturn
 144          *         syscall
 145          */
 146         if (PLAT_TRAMPOLINE_STUFF_LINE)
 147                 __clear_user(frame->rs_code, PLAT_TRAMPOLINE_STUFF_LINE);
 148         err |= __put_user(0x24020000 + __NR_N32_rt_sigreturn, frame->rs_code + 0);
 149         err |= __put_user(0x0000000c                        , frame->rs_code + 1);
 150         flush_cache_sigtramp((unsigned long) frame->rs_code);
 151
 152         /* Create siginfo.  */
 153         err |= copy_siginfo_to_user(&frame->rs_info, info);
 154
 155         /* Create the ucontext.  */
 156         err |= __put_user(0, &frame->rs_uc.uc_flags);
 157         err |= __put_user(0, &frame->rs_uc.uc_link);
 158         sp = (int) (long) current->sas_ss_sp;
 159         err |= __put_user(sp,
 160                           &frame->rs_uc.uc_stack.ss_sp);
 161         err |= __put_user(sas_ss_flags(regs->regs[29]),
 162                           &frame->rs_uc.uc_stack.ss_flags);
 163         err |= __put_user(current->sas_ss_size,
 164                           &frame->rs_uc.uc_stack.ss_size);
 165         err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 166         err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
 167
 168         if (err)
 169                 goto give_sigsegv;
 170
 171         /*
 172          * Arguments to signal handler:
 173          *
 174          *   a0 = signal number
 175          *   a1 = 0 (should be cause)
 176          *   a2 = pointer to ucontext
 177          *
 178          * $25 and c0_epc point to the signal handler, $29 points to
 179          * the struct rt_sigframe.
 180          */
 181         regs->regs[ 4] = signr;
 182         regs->regs[ 5] = (unsigned long) &frame->rs_info;
 183         regs->regs[ 6] = (unsigned long) &frame->rs_uc;
 184         regs->regs[29] = (unsigned long) frame;
 185         regs->regs[31] = (unsigned long) frame->rs_code;
 186         regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
 187
 188 #if DEBUG_SIG
 189         printk("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%p\n",
 190                current->comm, current->pid,
 191                frame, regs->cp0_epc, regs->regs[31]);
 192 #endif
 193         return;
 194
 195 give_sigsegv:
 196         force_sigsegv(signr, current);
 197 }