cw1200: When debug is enabled, display all wakeup conditions for the wait_event_inter...
[firefly-linux-kernel-4.4.55.git] / arch / um / kernel / signal.c
1 /*
2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3  * Licensed under the GPL
4  */
5
6 #include <linux/module.h>
7 #include <linux/ptrace.h>
8 #include <linux/sched.h>
9 #include <asm/siginfo.h>
10 #include <asm/signal.h>
11 #include <asm/unistd.h>
12 #include <frame_kern.h>
13 #include <kern_util.h>
14
15 EXPORT_SYMBOL(block_signals);
16 EXPORT_SYMBOL(unblock_signals);
17
18 /*
19  * OK, we're invoking a handler
20  */
21 static void handle_signal(struct pt_regs *regs, unsigned long signr,
22                          struct k_sigaction *ka, siginfo_t *info)
23 {
24         sigset_t *oldset = sigmask_to_save();
25         int singlestep = 0;
26         unsigned long sp;
27         int err;
28
29         if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
30                 singlestep = 1;
31
32         /* Did we come from a system call? */
33         if (PT_REGS_SYSCALL_NR(regs) >= 0) {
34                 /* If so, check system call restarting.. */
35                 switch (PT_REGS_SYSCALL_RET(regs)) {
36                 case -ERESTART_RESTARTBLOCK:
37                 case -ERESTARTNOHAND:
38                         PT_REGS_SYSCALL_RET(regs) = -EINTR;
39                         break;
40
41                 case -ERESTARTSYS:
42                         if (!(ka->sa.sa_flags & SA_RESTART)) {
43                                 PT_REGS_SYSCALL_RET(regs) = -EINTR;
44                                 break;
45                         }
46                 /* fallthrough */
47                 case -ERESTARTNOINTR:
48                         PT_REGS_RESTART_SYSCALL(regs);
49                         PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
50                         break;
51                 }
52         }
53
54         sp = PT_REGS_SP(regs);
55         if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
56                 sp = current->sas_ss_sp + current->sas_ss_size;
57
58 #ifdef CONFIG_ARCH_HAS_SC_SIGNALS
59         if (!(ka->sa.sa_flags & SA_SIGINFO))
60                 err = setup_signal_stack_sc(sp, signr, ka, regs, oldset);
61         else
62 #endif
63                 err = setup_signal_stack_si(sp, signr, ka, regs, info, oldset);
64
65         if (err)
66                 force_sigsegv(signr, current);
67         else
68                 signal_delivered(signr, info, ka, regs, singlestep);
69 }
70
71 static int kern_do_signal(struct pt_regs *regs)
72 {
73         struct k_sigaction ka_copy;
74         siginfo_t info;
75         int sig, handled_sig = 0;
76
77         while ((sig = get_signal_to_deliver(&info, &ka_copy, regs, NULL)) > 0) {
78                 handled_sig = 1;
79                 /* Whee!  Actually deliver the signal.  */
80                 handle_signal(regs, sig, &ka_copy, &info);
81         }
82
83         /* Did we come from a system call? */
84         if (!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)) {
85                 /* Restart the system call - no handlers present */
86                 switch (PT_REGS_SYSCALL_RET(regs)) {
87                 case -ERESTARTNOHAND:
88                 case -ERESTARTSYS:
89                 case -ERESTARTNOINTR:
90                         PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
91                         PT_REGS_RESTART_SYSCALL(regs);
92                         break;
93                 case -ERESTART_RESTARTBLOCK:
94                         PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall;
95                         PT_REGS_RESTART_SYSCALL(regs);
96                         break;
97                 }
98         }
99
100         /*
101          * This closes a way to execute a system call on the host.  If
102          * you set a breakpoint on a system call instruction and singlestep
103          * from it, the tracing thread used to PTRACE_SINGLESTEP the process
104          * rather than PTRACE_SYSCALL it, allowing the system call to execute
105          * on the host.  The tracing thread will check this flag and
106          * PTRACE_SYSCALL if necessary.
107          */
108         if (current->ptrace & PT_DTRACE)
109                 current->thread.singlestep_syscall =
110                         is_syscall(PT_REGS_IP(&current->thread.regs));
111
112         /*
113          * if there's no signal to deliver, we just put the saved sigmask
114          * back
115          */
116         if (!handled_sig)
117                 restore_saved_sigmask();
118         return handled_sig;
119 }
120
121 int do_signal(void)
122 {
123         return kern_do_signal(&current->thread.regs);
124 }