Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6
[linux-2.6] / arch / um / kernel / signal.c
1 /*
2  * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
3  * Licensed under the GPL
4  */
5
6 #include "linux/stddef.h"
7 #include "linux/sys.h"
8 #include "linux/sched.h"
9 #include "linux/wait.h"
10 #include "linux/kernel.h"
11 #include "linux/smp_lock.h"
12 #include "linux/module.h"
13 #include "linux/slab.h"
14 #include "linux/tty.h"
15 #include "linux/binfmts.h"
16 #include "linux/ptrace.h"
17 #include "asm/signal.h"
18 #include "asm/uaccess.h"
19 #include "asm/unistd.h"
20 #include "user_util.h"
21 #include "asm/ucontext.h"
22 #include "kern_util.h"
23 #include "signal_kern.h"
24 #include "kern.h"
25 #include "frame_kern.h"
26 #include "sigcontext.h"
27 #include "mode.h"
28
29 EXPORT_SYMBOL(block_signals);
30 EXPORT_SYMBOL(unblock_signals);
31
32 #define _S(nr) (1<<((nr)-1))
33
34 #define _BLOCKABLE (~(_S(SIGKILL) | _S(SIGSTOP)))
35
36 /*
37  * OK, we're invoking a handler
38  */
39 static int handle_signal(struct pt_regs *regs, unsigned long signr,
40                          struct k_sigaction *ka, siginfo_t *info,
41                          sigset_t *oldset)
42 {
43         unsigned long sp;
44         int err;
45
46         /* Always make any pending restarted system calls return -EINTR */
47         current_thread_info()->restart_block.fn = do_no_restart_syscall;
48
49         /* Did we come from a system call? */
50         if(PT_REGS_SYSCALL_NR(regs) >= 0){
51                 /* If so, check system call restarting.. */
52                 switch(PT_REGS_SYSCALL_RET(regs)){
53                 case -ERESTART_RESTARTBLOCK:
54                 case -ERESTARTNOHAND:
55                         PT_REGS_SYSCALL_RET(regs) = -EINTR;
56                         break;
57
58                 case -ERESTARTSYS:
59                         if (!(ka->sa.sa_flags & SA_RESTART)) {
60                                 PT_REGS_SYSCALL_RET(regs) = -EINTR;
61                                 break;
62                         }
63                 /* fallthrough */
64                 case -ERESTARTNOINTR:
65                         PT_REGS_RESTART_SYSCALL(regs);
66                         PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
67                         break;
68                 }
69         }
70
71         sp = PT_REGS_SP(regs);
72         if((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
73                 sp = current->sas_ss_sp + current->sas_ss_size;
74
75 #ifdef CONFIG_ARCH_HAS_SC_SIGNALS
76         if(!(ka->sa.sa_flags & SA_SIGINFO))
77                 err = setup_signal_stack_sc(sp, signr, ka, regs, oldset);
78         else
79 #endif
80                 err = setup_signal_stack_si(sp, signr, ka, regs, info, oldset);
81
82         if(err){
83                 spin_lock_irq(&current->sighand->siglock);
84                 current->blocked = *oldset;
85                 recalc_sigpending();
86                 spin_unlock_irq(&current->sighand->siglock);
87                 force_sigsegv(signr, current);
88         } else {
89                 spin_lock_irq(&current->sighand->siglock);
90                 sigorsets(&current->blocked, &current->blocked,
91                           &ka->sa.sa_mask);
92                  if(!(ka->sa.sa_flags & SA_NODEFER))
93                         sigaddset(&current->blocked, signr);
94                 recalc_sigpending();
95                 spin_unlock_irq(&current->sighand->siglock);
96         }
97
98         return err;
99 }
100
101 static int kern_do_signal(struct pt_regs *regs)
102 {
103         struct k_sigaction ka_copy;
104         siginfo_t info;
105         sigset_t *oldset;
106         int sig, handled_sig = 0;
107
108         if (test_thread_flag(TIF_RESTORE_SIGMASK))
109                 oldset = &current->saved_sigmask;
110         else
111                 oldset = &current->blocked;
112
113         while((sig = get_signal_to_deliver(&info, &ka_copy, regs, NULL)) > 0){
114                 handled_sig = 1;
115                 /* Whee!  Actually deliver the signal.  */
116                 if(!handle_signal(regs, sig, &ka_copy, &info, oldset)){
117                         /* a signal was successfully delivered; the saved
118                          * sigmask will have been stored in the signal frame,
119                          * and will be restored by sigreturn, so we can simply
120                          * clear the TIF_RESTORE_SIGMASK flag */
121                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
122                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
123                         break;
124                 }
125         }
126
127         /* Did we come from a system call? */
128         if(!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)){
129                 /* Restart the system call - no handlers present */
130                 switch(PT_REGS_SYSCALL_RET(regs)){
131                 case -ERESTARTNOHAND:
132                 case -ERESTARTSYS:
133                 case -ERESTARTNOINTR:
134                         PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
135                         PT_REGS_RESTART_SYSCALL(regs);
136                         break;
137                 case -ERESTART_RESTARTBLOCK:
138                         PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall;
139                         PT_REGS_RESTART_SYSCALL(regs);
140                         break;
141                 }
142         }
143
144         /* This closes a way to execute a system call on the host.  If
145          * you set a breakpoint on a system call instruction and singlestep
146          * from it, the tracing thread used to PTRACE_SINGLESTEP the process
147          * rather than PTRACE_SYSCALL it, allowing the system call to execute
148          * on the host.  The tracing thread will check this flag and
149          * PTRACE_SYSCALL if necessary.
150          */
151         if(current->ptrace & PT_DTRACE)
152                 current->thread.singlestep_syscall =
153                         is_syscall(PT_REGS_IP(&current->thread.regs));
154
155         /* if there's no signal to deliver, we just put the saved sigmask
156          * back */
157         if (!handled_sig && test_thread_flag(TIF_RESTORE_SIGMASK)) {
158                 clear_thread_flag(TIF_RESTORE_SIGMASK);
159                 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
160         }
161         return handled_sig;
162 }
163
164 int do_signal(void)
165 {
166         return kern_do_signal(&current->thread.regs);
167 }
168
169 /*
170  * Atomically swap in the new signal mask, and wait for a signal.
171  */
172 long sys_sigsuspend(int history0, int history1, old_sigset_t mask)
173 {
174         mask &= _BLOCKABLE;
175         spin_lock_irq(&current->sighand->siglock);
176         current->saved_sigmask = current->blocked;
177         siginitset(&current->blocked, mask);
178         recalc_sigpending();
179         spin_unlock_irq(&current->sighand->siglock);
180
181         current->state = TASK_INTERRUPTIBLE;
182         schedule();
183         set_thread_flag(TIF_RESTORE_SIGMASK);
184         return -ERESTARTNOHAND;
185 }
186
187 long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
188 {
189         return do_sigaltstack(uss, uoss, PT_REGS_SP(&current->thread.regs));
190 }