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 28 #include "signal-common.h" 29 30 /* 31 * Including <asm/unistd.h> would give use the 64-bit syscall numbers ... 32 */ 33 #define __NR_N32_restart_syscall 6214 34 35 extern int setup_sigcontext(struct pt_regs *, struct sigcontext __user *); 36 extern int restore_sigcontext(struct pt_regs *, struct sigcontext __user *); 37 38 struct ucontextn32 { 39 u32 uc_flags; 40 s32 uc_link; 41 compat_stack_t uc_stack; 42 struct sigcontext uc_mcontext; 43 compat_sigset_t uc_sigmask; /* mask last for extensibility */ 44 }; 45 46 struct rt_sigframe_n32 { 47 u32 rs_ass[4]; /* argument save space for o32 */ 48 u32 rs_pad[2]; /* Was: signal trampoline */ 49 struct compat_siginfo rs_info; 50 struct ucontextn32 rs_uc; 51 }; 52 53 asmlinkage void sysn32_rt_sigreturn(void) 54 { 55 struct rt_sigframe_n32 __user *frame; 56 struct pt_regs *regs; 57 sigset_t set; 58 int sig; 59 60 regs = current_pt_regs(); 61 frame = (struct rt_sigframe_n32 __user *)regs->regs[29]; 62 if (!access_ok(frame, sizeof(*frame))) 63 goto badframe; 64 if (__copy_conv_sigset_from_user(&set, &frame->rs_uc.uc_sigmask)) 65 goto badframe; 66 67 set_current_blocked(&set); 68 69 sig = restore_sigcontext(regs, &frame->rs_uc.uc_mcontext); 70 if (sig < 0) 71 goto badframe; 72 else if (sig) 73 force_sig(sig); 74 75 if (compat_restore_altstack(&frame->rs_uc.uc_stack)) 76 goto badframe; 77 78 /* 79 * Don't let your children do this ... 80 */ 81 __asm__ __volatile__( 82 "move\t$29, %0\n\t" 83 "j\tsyscall_exit" 84 : /* no outputs */ 85 : "r" (regs)); 86 /* Unreached */ 87 88 badframe: 89 force_sig(SIGSEGV); 90 } 91 92 static int setup_rt_frame_n32(void *sig_return, struct ksignal *ksig, 93 struct pt_regs *regs, sigset_t *set) 94 { 95 struct rt_sigframe_n32 __user *frame; 96 int err = 0; 97 98 frame = get_sigframe(ksig, regs, sizeof(*frame)); 99 if (!access_ok(frame, sizeof (*frame))) 100 return -EFAULT; 101 102 /* Create siginfo. */ 103 err |= copy_siginfo_to_user32(&frame->rs_info, &ksig->info); 104 105 /* Create the ucontext. */ 106 err |= __put_user(0, &frame->rs_uc.uc_flags); 107 err |= __put_user(0, &frame->rs_uc.uc_link); 108 err |= __compat_save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]); 109 err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext); 110 err |= __copy_conv_sigset_to_user(&frame->rs_uc.uc_sigmask, set); 111 112 if (err) 113 return -EFAULT; 114 115 /* 116 * Arguments to signal handler: 117 * 118 * a0 = signal number 119 * a1 = 0 (should be cause) 120 * a2 = pointer to ucontext 121 * 122 * $25 and c0_epc point to the signal handler, $29 points to 123 * the struct rt_sigframe. 124 */ 125 regs->regs[ 4] = ksig->sig; 126 regs->regs[ 5] = (unsigned long) &frame->rs_info; 127 regs->regs[ 6] = (unsigned long) &frame->rs_uc; 128 regs->regs[29] = (unsigned long) frame; 129 regs->regs[31] = (unsigned long) sig_return; 130 regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler; 131 132 DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n", 133 current->comm, current->pid, 134 frame, regs->cp0_epc, regs->regs[31]); 135 136 return 0; 137 } 138 139 struct mips_abi mips_abi_n32 = { 140 .setup_rt_frame = setup_rt_frame_n32, 141 .restart = __NR_N32_restart_syscall, 142 143 .off_sc_fpregs = offsetof(struct sigcontext, sc_fpregs), 144 .off_sc_fpc_csr = offsetof(struct sigcontext, sc_fpc_csr), 145 .off_sc_used_math = offsetof(struct sigcontext, sc_used_math), 146 147 .vdso = &vdso_image_n32, 148 }; 149