1 /* 2 * Common signal handling code for both 32 and 64 bits 3 * 4 * Copyright (c) 2007 Benjamin Herrenschmidt, IBM Coproration 5 * Extracted from signal_32.c and signal_64.c 6 * 7 * This file is subject to the terms and conditions of the GNU General 8 * Public License. See the file README.legal in the main directory of 9 * this archive for more details. 10 */ 11 12 #include <linux/ptrace.h> 13 #include <linux/signal.h> 14 #include <asm/uaccess.h> 15 #include <asm/unistd.h> 16 17 #include "signal.h" 18 19 /* 20 * Allocate space for the signal frame 21 */ 22 void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, 23 size_t frame_size) 24 { 25 unsigned long oldsp, newsp; 26 27 /* Default to using normal stack */ 28 oldsp = regs->gpr[1]; 29 30 /* Check for alt stack */ 31 if ((ka->sa.sa_flags & SA_ONSTACK) && 32 current->sas_ss_size && !on_sig_stack(oldsp)) 33 oldsp = (current->sas_ss_sp + current->sas_ss_size); 34 35 /* Get aligned frame */ 36 newsp = (oldsp - frame_size) & ~0xFUL; 37 38 /* Check access */ 39 if (!access_ok(VERIFY_WRITE, (void __user *)newsp, oldsp - newsp)) 40 return NULL; 41 42 return (void __user *)newsp; 43 } 44 45 46 /* 47 * Restore the user process's signal mask 48 */ 49 void restore_sigmask(sigset_t *set) 50 { 51 sigdelsetmask(set, ~_BLOCKABLE); 52 spin_lock_irq(¤t->sighand->siglock); 53 current->blocked = *set; 54 recalc_sigpending(); 55 spin_unlock_irq(¤t->sighand->siglock); 56 } 57 58 static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka, 59 int has_handler) 60 { 61 unsigned long ret = regs->gpr[3]; 62 int restart = 1; 63 64 /* syscall ? */ 65 if (TRAP(regs) != 0x0C00) 66 return; 67 68 /* error signalled ? */ 69 if (!(regs->ccr & 0x10000000)) 70 return; 71 72 switch (ret) { 73 case ERESTART_RESTARTBLOCK: 74 case ERESTARTNOHAND: 75 /* ERESTARTNOHAND means that the syscall should only be 76 * restarted if there was no handler for the signal, and since 77 * we only get here if there is a handler, we dont restart. 78 */ 79 restart = !has_handler; 80 break; 81 case ERESTARTSYS: 82 /* ERESTARTSYS means to restart the syscall if there is no 83 * handler or the handler was registered with SA_RESTART 84 */ 85 restart = !has_handler || (ka->sa.sa_flags & SA_RESTART) != 0; 86 break; 87 case ERESTARTNOINTR: 88 /* ERESTARTNOINTR means that the syscall should be 89 * called again after the signal handler returns. 90 */ 91 break; 92 default: 93 return; 94 } 95 if (restart) { 96 if (ret == ERESTART_RESTARTBLOCK) 97 regs->gpr[0] = __NR_restart_syscall; 98 else 99 regs->gpr[3] = regs->orig_gpr3; 100 regs->nip -= 4; 101 regs->result = 0; 102 } else { 103 regs->result = -EINTR; 104 regs->gpr[3] = EINTR; 105 regs->ccr |= 0x10000000; 106 } 107 } 108 109 int do_signal(sigset_t *oldset, struct pt_regs *regs) 110 { 111 siginfo_t info; 112 int signr; 113 struct k_sigaction ka; 114 int ret; 115 int is32 = is_32bit_task(); 116 117 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 118 oldset = ¤t->saved_sigmask; 119 else if (!oldset) 120 oldset = ¤t->blocked; 121 122 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 123 124 /* Is there any syscall restart business here ? */ 125 check_syscall_restart(regs, &ka, signr > 0); 126 127 if (signr <= 0) { 128 /* No signal to deliver -- put the saved sigmask back */ 129 if (test_thread_flag(TIF_RESTORE_SIGMASK)) { 130 clear_thread_flag(TIF_RESTORE_SIGMASK); 131 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); 132 } 133 return 0; /* no signals delivered */ 134 } 135 136 /* 137 * Reenable the DABR before delivering the signal to 138 * user space. The DABR will have been cleared if it 139 * triggered inside the kernel. 140 */ 141 if (current->thread.dabr) 142 set_dabr(current->thread.dabr); 143 144 if (is32) { 145 if (ka.sa.sa_flags & SA_SIGINFO) 146 ret = handle_rt_signal32(signr, &ka, &info, oldset, 147 regs); 148 else 149 ret = handle_signal32(signr, &ka, &info, oldset, 150 regs); 151 } else { 152 ret = handle_rt_signal64(signr, &ka, &info, oldset, regs); 153 } 154 155 if (ret) { 156 spin_lock_irq(¤t->sighand->siglock); 157 sigorsets(¤t->blocked, ¤t->blocked, 158 &ka.sa.sa_mask); 159 if (!(ka.sa.sa_flags & SA_NODEFER)) 160 sigaddset(¤t->blocked, signr); 161 recalc_sigpending(); 162 spin_unlock_irq(¤t->sighand->siglock); 163 164 /* 165 * A signal was successfully delivered; the saved sigmask is in 166 * its frame, and we can clear the TIF_RESTORE_SIGMASK flag. 167 */ 168 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 169 clear_thread_flag(TIF_RESTORE_SIGMASK); 170 } 171 172 return ret; 173 } 174 175 long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, 176 unsigned long r5, unsigned long r6, unsigned long r7, 177 unsigned long r8, struct pt_regs *regs) 178 { 179 return do_sigaltstack(uss, uoss, regs->gpr[1]); 180 } 181