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