LXR linux/arch/mips/kernel/signal

   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/war.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
  36extern int setup_sigcontext(struct pt_regs *, struct sigcontext __user *);
  37extern int restore_sigcontext(struct pt_regs *, struct sigcontext __user *);
  38
  39struct ucontextn32 {
  40        u32                 uc_flags;
  41        s32                 uc_link;
  42        compat_stack_t      uc_stack;
  43        struct sigcontext   uc_mcontext;
  44        compat_sigset_t     uc_sigmask;   /* mask last for extensibility */
  45};
  46
  47struct rt_sigframe_n32 {
  48        u32 rs_ass[4];                  /* argument save space for o32 */
  49        u32 rs_pad[2];                  /* Was: signal trampoline */
  50        struct compat_siginfo rs_info;
  51        struct ucontextn32 rs_uc;
  52};
  53
  54asmlinkage void sysn32_rt_sigreturn(void)
  55{
  56        struct rt_sigframe_n32 __user *frame;
  57        struct pt_regs *regs;
  58        sigset_t set;
  59        int sig;
  60
  61        regs = current_pt_regs();
  62        frame = (struct rt_sigframe_n32 __user *)regs->regs[29];
  63        if (!access_ok(frame, sizeof(*frame)))
  64                goto badframe;
  65        if (__copy_conv_sigset_from_user(&set, &frame->rs_uc.uc_sigmask))
  66                goto badframe;
  67
  68        set_current_blocked(&set);
  69
  70        sig = restore_sigcontext(regs, &frame->rs_uc.uc_mcontext);
  71        if (sig < 0)
  72                goto badframe;
  73        else if (sig)
  74                force_sig(sig);
  75
  76        if (compat_restore_altstack(&frame->rs_uc.uc_stack))
  77                goto badframe;
  78
  79        /*
  80         * Don't let your children do this ...
  81         */
  82        __asm__ __volatile__(
  83                "move\t$29, %0\n\t"
  84                "j\tsyscall_exit"
  85                : /* no outputs */
  86                : "r" (regs));
  87        /* Unreached */
  88
  89badframe:
  90        force_sig(SIGSEGV);
  91}
  92
  93static int setup_rt_frame_n32(void *sig_return, struct ksignal *ksig,
  94                              struct pt_regs *regs, sigset_t *set)
  95{
  96        struct rt_sigframe_n32 __user *frame;
  97        int err = 0;
  98
  99        frame = get_sigframe(ksig, regs, sizeof(*frame));
 100        if (!access_ok(frame, sizeof (*frame)))
 101                return -EFAULT;
 102
 103        /* Create siginfo.  */
 104        err |= copy_siginfo_to_user32(&frame->rs_info, &ksig->info);
 105
 106        /* Create the ucontext.  */
 107        err |= __put_user(0, &frame->rs_uc.uc_flags);
 108        err |= __put_user(0, &frame->rs_uc.uc_link);
 109        err |= __compat_save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
 110        err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
 111        err |= __copy_conv_sigset_to_user(&frame->rs_uc.uc_sigmask, set);
 112
 113        if (err)
 114                return -EFAULT;
 115
 116        /*
 117         * Arguments to signal handler:
 118         *
 119         *   a0 = signal number
 120         *   a1 = 0 (should be cause)
 121         *   a2 = pointer to ucontext
 122         *
 123         * $25 and c0_epc point to the signal handler, $29 points to
 124         * the struct rt_sigframe.
 125         */
 126        regs->regs[ 4] = ksig->sig;
 127        regs->regs[ 5] = (unsigned long) &frame->rs_info;
 128        regs->regs[ 6] = (unsigned long) &frame->rs_uc;
 129        regs->regs[29] = (unsigned long) frame;
 130        regs->regs[31] = (unsigned long) sig_return;
 131        regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
 132
 133        DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
 134               current->comm, current->pid,
 135               frame, regs->cp0_epc, regs->regs[31]);
 136
 137        return 0;
 138}
 139
 140struct mips_abi mips_abi_n32 = {
 141        .setup_rt_frame = setup_rt_frame_n32,
 142        .restart        = __NR_N32_restart_syscall,
 143
 144        .off_sc_fpregs = offsetof(struct sigcontext, sc_fpregs),
 145        .off_sc_fpc_csr = offsetof(struct sigcontext, sc_fpc_csr),
 146        .off_sc_used_math = offsetof(struct sigcontext, sc_used_math),
 147
 148        .vdso           = &vdso_image_n32,
 149};
 150