mips/kernel/signal_n32.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * Copyright (C) 2003 Broadcom Corporation
0004  */
0005 #include <linux/cache.h>
0006 #include <linux/sched.h>
0007 #include <linux/mm.h>
0008 #include <linux/smp.h>
0009 #include <linux/kernel.h>
0010 #include <linux/signal.h>
0011 #include <linux/errno.h>
0012 #include <linux/wait.h>
0013 #include <linux/ptrace.h>
0014 #include <linux/unistd.h>
0015 #include <linux/compat.h>
0016 #include <linux/bitops.h>
0017
0018 #include <asm/abi.h>
0019 #include <asm/asm.h>
0020 #include <asm/cacheflush.h>
0021 #include <asm/compat-signal.h>
0022 #include <asm/sim.h>
0023 #include <linux/uaccess.h>
0024 #include <asm/ucontext.h>
0025 #include <asm/fpu.h>
0026 #include <asm/cpu-features.h>
0027
0028 #include "signal-common.h"
0029
0030 /*
0031  * Including <asm/unistd.h> would give use the 64-bit syscall numbers ...
0032  */
0033 #define __NR_N32_restart_syscall    6214
0034
0035 extern int setup_sigcontext(struct pt_regs *, struct sigcontext __user *);
0036 extern int restore_sigcontext(struct pt_regs *, struct sigcontext __user *);
0037
0038 struct ucontextn32 {
0039     u32         uc_flags;
0040     s32         uc_link;
0041     compat_stack_t      uc_stack;
0042     struct sigcontext   uc_mcontext;
0043     compat_sigset_t     uc_sigmask;   /* mask last for extensibility */
0044 };
0045
0046 struct rt_sigframe_n32 {
0047     u32 rs_ass[4];          /* argument save space for o32 */
0048     u32 rs_pad[2];          /* Was: signal trampoline */
0049     struct compat_siginfo rs_info;
0050     struct ucontextn32 rs_uc;
0051 };
0052
0053 asmlinkage void sysn32_rt_sigreturn(void)
0054 {
0055     struct rt_sigframe_n32 __user *frame;
0056     struct pt_regs *regs;
0057     sigset_t set;
0058     int sig;
0059
0060     regs = current_pt_regs();
0061     frame = (struct rt_sigframe_n32 __user *)regs->regs[29];
0062     if (!access_ok(frame, sizeof(*frame)))
0063         goto badframe;
0064     if (__copy_conv_sigset_from_user(&set, &frame->rs_uc.uc_sigmask))
0065         goto badframe;
0066
0067     set_current_blocked(&set);
0068
0069     sig = restore_sigcontext(regs, &frame->rs_uc.uc_mcontext);
0070     if (sig < 0)
0071         goto badframe;
0072     else if (sig)
0073         force_sig(sig);
0074
0075     if (compat_restore_altstack(&frame->rs_uc.uc_stack))
0076         goto badframe;
0077
0078     /*
0079      * Don't let your children do this ...
0080      */
0081     __asm__ __volatile__(
0082         "move\t$29, %0\n\t"
0083         "j\tsyscall_exit"
0084         : /* no outputs */
0085         : "r" (regs));
0086     /* Unreached */
0087
0088 badframe:
0089     force_sig(SIGSEGV);
0090 }
0091
0092 static int setup_rt_frame_n32(void *sig_return, struct ksignal *ksig,
0093                   struct pt_regs *regs, sigset_t *set)
0094 {
0095     struct rt_sigframe_n32 __user *frame;
0096     int err = 0;
0097
0098     frame = get_sigframe(ksig, regs, sizeof(*frame));
0099     if (!access_ok(frame, sizeof (*frame)))
0100         return -EFAULT;
0101
0102     /* Create siginfo.  */
0103     err |= copy_siginfo_to_user32(&frame->rs_info, &ksig->info);
0104
0105     /* Create the ucontext.  */
0106     err |= __put_user(0, &frame->rs_uc.uc_flags);
0107     err |= __put_user(0, &frame->rs_uc.uc_link);
0108     err |= __compat_save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
0109     err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
0110     err |= __copy_conv_sigset_to_user(&frame->rs_uc.uc_sigmask, set);
0111
0112     if (err)
0113         return -EFAULT;
0114
0115     /*
0116      * Arguments to signal handler:
0117      *
0118      *   a0 = signal number
0119      *   a1 = 0 (should be cause)
0120      *   a2 = pointer to ucontext
0121      *
0122      * $25 and c0_epc point to the signal handler, $29 points to
0123      * the struct rt_sigframe.
0124      */
0125     regs->regs[ 4] = ksig->sig;
0126     regs->regs[ 5] = (unsigned long) &frame->rs_info;
0127     regs->regs[ 6] = (unsigned long) &frame->rs_uc;
0128     regs->regs[29] = (unsigned long) frame;
0129     regs->regs[31] = (unsigned long) sig_return;
0130     regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
0131
0132     DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
0133            current->comm, current->pid,
0134            frame, regs->cp0_epc, regs->regs[31]);
0135
0136     return 0;
0137 }
0138
0139 struct mips_abi mips_abi_n32 = {
0140     .setup_rt_frame = setup_rt_frame_n32,
0141     .restart    = __NR_N32_restart_syscall,
0142
0143     .off_sc_fpregs = offsetof(struct sigcontext, sc_fpregs),
0144     .off_sc_fpc_csr = offsetof(struct sigcontext, sc_fpc_csr),
0145     .off_sc_used_math = offsetof(struct sigcontext, sc_used_math),
0146
0147     .vdso       = &vdso_image_n32,
0148 };