2 * linux/arch/cris/kernel/signal.c
4 * Based on arch/i386/kernel/signal.c by
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson *
8 * Ideas also taken from arch/arm.
10 * Copyright (C) 2000-2007 Axis Communications AB
12 * Authors: Bjorn Wesen (bjornw@axis.com)
16 #include <linux/sched.h>
18 #include <linux/smp.h>
19 #include <linux/kernel.h>
20 #include <linux/signal.h>
21 #include <linux/errno.h>
22 #include <linux/wait.h>
23 #include <linux/ptrace.h>
24 #include <linux/unistd.h>
25 #include <linux/stddef.h>
27 #include <asm/processor.h>
28 #include <asm/ucontext.h>
29 #include <asm/uaccess.h>
30 #include <arch/system.h>
34 /* a syscall in Linux/CRIS is a break 13 instruction which is 2 bytes */
35 /* manipulate regs so that upon return, it will be re-executed */
37 /* We rely on that pc points to the instruction after "break 13", so the
38 * library must never do strange things like putting it in a delay slot.
40 #define RESTART_CRIS_SYS(regs) regs->r10 = regs->orig_r10; regs->irp -= 2;
42 void do_signal(int canrestart, struct pt_regs *regs);
45 * Do a signal return; undo the signal stack.
50 unsigned long extramask[_NSIG_WORDS-1];
51 unsigned char retcode[8]; /* trampoline code */
55 struct siginfo *pinfo;
59 unsigned char retcode[8]; /* trampoline code */
64 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
67 unsigned long old_usp;
69 /* Always make any pending restarted system calls return -EINTR */
70 current_thread_info()->restart_block.fn = do_no_restart_syscall;
72 /* restore the regs from &sc->regs (same as sc, since regs is first)
73 * (sc is already checked for VERIFY_READ since the sigframe was
74 * checked in sys_sigreturn previously)
77 if (__copy_from_user(regs, sc, sizeof(struct pt_regs)))
80 /* make sure the U-flag is set so user-mode cannot fool us */
84 /* restore the old USP as it was before we stacked the sc etc.
85 * (we cannot just pop the sigcontext since we aligned the sp and
86 * stuff after pushing it)
89 err |= __get_user(old_usp, &sc->usp);
93 /* TODO: the other ports use regs->orig_XX to disable syscall checks
94 * after this completes, but we don't use that mechanism. maybe we can
104 asmlinkage int sys_sigreturn(void)
106 struct pt_regs *regs = current_pt_regs();
107 struct sigframe __user *frame = (struct sigframe *)rdusp();
111 * Since we stacked the signal on a dword boundary,
112 * then frame should be dword aligned here. If it's
113 * not, then the user is trying to mess with us.
115 if (((long)frame) & 3)
118 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
120 if (__get_user(set.sig[0], &frame->sc.oldmask)
122 && __copy_from_user(&set.sig[1], frame->extramask,
123 sizeof(frame->extramask))))
126 set_current_blocked(&set);
128 if (restore_sigcontext(regs, &frame->sc))
131 /* TODO: SIGTRAP when single-stepping as in arm ? */
136 force_sig(SIGSEGV, current);
140 asmlinkage int sys_rt_sigreturn(void)
142 struct pt_regs *regs = current_pt_regs();
143 struct rt_sigframe __user *frame = (struct rt_sigframe *)rdusp();
147 * Since we stacked the signal on a dword boundary,
148 * then frame should be dword aligned here. If it's
149 * not, then the user is trying to mess with us.
151 if (((long)frame) & 3)
154 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
156 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
159 set_current_blocked(&set);
161 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
164 if (restore_altstack(&frame->uc.uc_stack))
170 force_sig(SIGSEGV, current);
175 * Set up a signal frame.
178 static int setup_sigcontext(struct sigcontext __user *sc,
179 struct pt_regs *regs, unsigned long mask)
182 unsigned long usp = rdusp();
184 /* copy the regs. they are first in sc so we can use sc directly */
186 err |= __copy_to_user(sc, regs, sizeof(struct pt_regs));
188 /* Set the frametype to CRIS_FRAME_NORMAL for the execution of
189 the signal handler. The frametype will be restored to its previous
190 value in restore_sigcontext. */
191 regs->frametype = CRIS_FRAME_NORMAL;
193 /* then some other stuff */
195 err |= __put_user(mask, &sc->oldmask);
197 err |= __put_user(usp, &sc->usp);
202 /* Figure out where we want to put the new signal frame
203 * - usually on the stack. */
205 static inline void __user *
206 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
208 unsigned long sp = rdusp();
210 /* This is the X/Open sanctioned signal stack switching. */
211 if (ka->sa.sa_flags & SA_ONSTACK) {
212 if (! on_sig_stack(sp))
213 sp = current->sas_ss_sp + current->sas_ss_size;
216 /* make sure the frame is dword-aligned */
220 return (void __user*)(sp - frame_size);
223 /* grab and setup a signal frame.
225 * basically we stack a lot of state info, and arrange for the
226 * user-mode program to return to the kernel using either a
227 * trampoline which performs the syscall sigreturn, or a provided
228 * user-mode trampoline.
231 static int setup_frame(int sig, struct k_sigaction *ka,
232 sigset_t *set, struct pt_regs *regs)
234 struct sigframe __user *frame;
235 unsigned long return_ip;
238 frame = get_sigframe(ka, regs, sizeof(*frame));
240 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
243 err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
247 if (_NSIG_WORDS > 1) {
248 err |= __copy_to_user(frame->extramask, &set->sig[1],
249 sizeof(frame->extramask));
254 /* Set up to return from userspace. If provided, use a stub
255 already in userspace. */
256 if (ka->sa.sa_flags & SA_RESTORER) {
257 return_ip = (unsigned long)ka->sa.sa_restorer;
259 /* trampoline - the desired return ip is the retcode itself */
260 return_ip = (unsigned long)&frame->retcode;
261 /* This is movu.w __NR_sigreturn, r9; break 13; */
262 err |= __put_user(0x9c5f, (short __user*)(frame->retcode+0));
263 err |= __put_user(__NR_sigreturn, (short __user*)(frame->retcode+2));
264 err |= __put_user(0xe93d, (short __user*)(frame->retcode+4));
270 /* Set up registers for signal handler */
272 regs->irp = (unsigned long) ka->sa.sa_handler; /* what we enter NOW */
273 regs->srp = return_ip; /* what we enter LATER */
274 regs->r10 = sig; /* first argument is signo */
276 /* actually move the usp to reflect the stacked frame */
278 wrusp((unsigned long)frame);
283 force_sigsegv(sig, current);
287 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
288 sigset_t *set, struct pt_regs *regs)
290 struct rt_sigframe __user *frame;
291 unsigned long return_ip;
294 frame = get_sigframe(ka, regs, sizeof(*frame));
296 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
299 err |= __put_user(&frame->info, &frame->pinfo);
300 err |= __put_user(&frame->uc, &frame->puc);
301 err |= copy_siginfo_to_user(&frame->info, info);
305 /* Clear all the bits of the ucontext we don't use. */
306 err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
308 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
310 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
312 err |= __save_altstack(&frame->uc.uc_stack, rdusp());
317 /* Set up to return from userspace. If provided, use a stub
318 already in userspace. */
319 if (ka->sa.sa_flags & SA_RESTORER) {
320 return_ip = (unsigned long)ka->sa.sa_restorer;
322 /* trampoline - the desired return ip is the retcode itself */
323 return_ip = (unsigned long)&frame->retcode;
324 /* This is movu.w __NR_rt_sigreturn, r9; break 13; */
325 err |= __put_user(0x9c5f, (short __user *)(frame->retcode+0));
326 err |= __put_user(__NR_rt_sigreturn,
327 (short __user *)(frame->retcode+2));
328 err |= __put_user(0xe93d, (short __user *)(frame->retcode+4));
334 /* TODO what is the current->exec_domain stuff and invmap ? */
336 /* Set up registers for signal handler */
338 /* What we enter NOW */
339 regs->irp = (unsigned long) ka->sa.sa_handler;
340 /* What we enter LATER */
341 regs->srp = return_ip;
342 /* First argument is signo */
344 /* Second argument is (siginfo_t *) */
345 regs->r11 = (unsigned long)&frame->info;
346 /* Third argument is unused */
349 /* Actually move the usp to reflect the stacked frame */
350 wrusp((unsigned long)frame);
355 force_sigsegv(sig, current);
360 * OK, we're invoking a handler
363 static inline void handle_signal(int canrestart, unsigned long sig,
364 siginfo_t *info, struct k_sigaction *ka,
365 struct pt_regs *regs)
367 sigset_t *oldset = sigmask_to_save();
370 /* Are we from a system call? */
372 /* If so, check system call restarting.. */
374 case -ERESTART_RESTARTBLOCK:
375 case -ERESTARTNOHAND:
376 /* ERESTARTNOHAND means that the syscall should
377 * only be restarted if there was no handler for
378 * the signal, and since we only get here if there
379 * is a handler, we don't restart */
383 /* ERESTARTSYS means to restart the syscall if
384 * there is no handler or the handler was
385 * registered with SA_RESTART */
386 if (!(ka->sa.sa_flags & SA_RESTART)) {
391 case -ERESTARTNOINTR:
392 /* ERESTARTNOINTR means that the syscall should
393 * be called again after the signal handler returns. */
394 RESTART_CRIS_SYS(regs);
398 /* Set up the stack frame */
399 if (ka->sa.sa_flags & SA_SIGINFO)
400 ret = setup_rt_frame(sig, ka, info, oldset, regs);
402 ret = setup_frame(sig, ka, oldset, regs);
405 signal_delivered(sig, info, ka, regs, 0);
409 * Note that 'init' is a special process: it doesn't get signals it doesn't
410 * want to handle. Thus you cannot kill init even with a SIGKILL even by
413 * Also note that the regs structure given here as an argument, is the latest
414 * pushed pt_regs. It may or may not be the same as the first pushed registers
415 * when the initial usermode->kernelmode transition took place. Therefore
416 * we can use user_mode(regs) to see if we came directly from kernel or user
420 void do_signal(int canrestart, struct pt_regs *regs)
424 struct k_sigaction ka;
427 * We want the common case to go fast, which
428 * is why we may in certain cases get here from
429 * kernel mode. Just return without doing anything
432 if (!user_mode(regs))
435 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
437 /* Whee! Actually deliver the signal. */
438 handle_signal(canrestart, signr, &info, &ka, regs);
442 /* Did we come from a system call? */
444 /* Restart the system call - no handlers present */
445 if (regs->r10 == -ERESTARTNOHAND ||
446 regs->r10 == -ERESTARTSYS ||
447 regs->r10 == -ERESTARTNOINTR) {
448 RESTART_CRIS_SYS(regs);
450 if (regs->r10 == -ERESTART_RESTARTBLOCK) {
451 regs->r9 = __NR_restart_syscall;
456 /* if there's no signal to deliver, we just put the saved sigmask
458 restore_saved_sigmask();