arch/mips/kernel/signal_n32.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2003 Broadcom Corporation
   4  */
   5 #include <linux/cache.h>
   6 #include <linux/sched.h>
   7 #include <linux/mm.h>
   8 #include <linux/smp.h>
   9 #include <linux/kernel.h>
  10 #include <linux/signal.h>
  11 #include <linux/errno.h>
  12 #include <linux/wait.h>
  13 #include <linux/ptrace.h>
  14 #include <linux/unistd.h>
  15 #include <linux/compat.h>
  16 #include <linux/bitops.h>
  17
  18 #include <asm/abi.h>
  19 #include <asm/asm.h>
  20 #include <asm/cacheflush.h>
  21 #include <asm/compat-signal.h>
  22 #include <asm/sim.h>
  23 #include <linux/uaccess.h>
  24 #include <asm/ucontext.h>
  25 #include <asm/fpu.h>
  26 #include <asm/cpu-features.h>
  27 #include <asm/syscalls.h>
  28
  29 #include "signal-common.h"
  30
  31 /*
  32  * Including <asm/unistd.h> would give use the 64-bit syscall numbers ...
  33  */
  34 #define __NR_N32_restart_syscall        6214
  35
  36 struct ucontextn32 {
  37         u32                 uc_flags;
  38         s32                 uc_link;
  39         compat_stack_t      uc_stack;
  40         struct sigcontext   uc_mcontext;
  41         compat_sigset_t     uc_sigmask;   /* mask last for extensibility */
  42 };
  43
  44 struct rt_sigframe_n32 {
  45         u32 rs_ass[4];                  /* argument save space for o32 */
  46         u32 rs_pad[2];                  /* Was: signal trampoline */
  47         struct compat_siginfo rs_info;
  48         struct ucontextn32 rs_uc;
  49 };
  50
  51 asmlinkage void sysn32_rt_sigreturn(void)
  52 {
  53         struct rt_sigframe_n32 __user *frame;
  54         struct pt_regs *regs;
  55         sigset_t set;
  56         int sig;
  57
  58         regs = current_pt_regs();
  59         frame = (struct rt_sigframe_n32 __user *)regs->regs[29];
  60         if (!access_ok(frame, sizeof(*frame)))
  61                 goto badframe;
  62         if (__copy_conv_sigset_from_user(&set, &frame->rs_uc.uc_sigmask))
  63                 goto badframe;
  64
  65         set_current_blocked(&set);
  66
  67         sig = restore_sigcontext(regs, &frame->rs_uc.uc_mcontext);
  68         if (sig < 0)
  69                 goto badframe;
  70         else if (sig)
  71                 force_sig(sig);
  72
  73         if (compat_restore_altstack(&frame->rs_uc.uc_stack))
  74                 goto badframe;
  75
  76         /*
  77          * Don't let your children do this ...
  78          */
  79         __asm__ __volatile__(
  80                 "move\t$29, %0\n\t"
  81                 "j\tsyscall_exit"
  82                 : /* no outputs */
  83                 : "r" (regs));
  84         /* Unreached */
  85
  86 badframe:
  87         force_sig(SIGSEGV);
  88 }
  89
  90 static int setup_rt_frame_n32(void *sig_return, struct ksignal *ksig,
  91                               struct pt_regs *regs, sigset_t *set)
  92 {
  93         struct rt_sigframe_n32 __user *frame;
  94         int err = 0;
  95
  96         frame = get_sigframe(ksig, regs, sizeof(*frame));
  97         if (!access_ok(frame, sizeof (*frame)))
  98                 return -EFAULT;
  99
 100         /* Create siginfo.  */
 101         err |= copy_siginfo_to_user32(&frame->rs_info, &ksig->info);
 102
 103         /* Create the ucontext.  */
 104         err |= __put_user(0, &frame->rs_uc.uc_flags);
 105         err |= __put_user(0, &frame->rs_uc.uc_link);
 106         err |= __compat_save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
 107         err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 108         err |= __copy_conv_sigset_to_user(&frame->rs_uc.uc_sigmask, set);
 109
 110         if (err)
 111                 return -EFAULT;
 112
 113         /*
 114          * Arguments to signal handler:
 115          *
 116          *   a0 = signal number
 117          *   a1 = 0 (should be cause)
 118          *   a2 = pointer to ucontext
 119          *
 120          * $25 and c0_epc point to the signal handler, $29 points to
 121          * the struct rt_sigframe.
 122          */
 123         regs->regs[ 4] = ksig->sig;
 124         regs->regs[ 5] = (unsigned long) &frame->rs_info;
 125         regs->regs[ 6] = (unsigned long) &frame->rs_uc;
 126         regs->regs[29] = (unsigned long) frame;
 127         regs->regs[31] = (unsigned long) sig_return;
 128         regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
 129
 130         DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 131                current->comm, current->pid,
 132                frame, regs->cp0_epc, regs->regs[31]);
 133
 134         return 0;
 135 }
 136
 137 struct mips_abi mips_abi_n32 = {
 138         .setup_rt_frame = setup_rt_frame_n32,
 139         .restart        = __NR_N32_restart_syscall,
 140
 141         .off_sc_fpregs = offsetof(struct sigcontext, sc_fpregs),
 142         .off_sc_fpc_csr = offsetof(struct sigcontext, sc_fpc_csr),
 143         .off_sc_used_math = offsetof(struct sigcontext, sc_used_math),
 144
 145         .vdso           = &vdso_image_n32,
 146 };