2 * Copyright (C) 2003, Axis Communications AB.
5 #include <linux/sched.h>
7 #include <linux/slab.h>
8 #include <linux/kernel.h>
9 #include <linux/signal.h>
10 #include <linux/errno.h>
11 #include <linux/wait.h>
12 #include <linux/ptrace.h>
13 #include <linux/unistd.h>
14 #include <linux/stddef.h>
15 #include <linux/syscalls.h>
16 #include <linux/vmalloc.h>
19 #include <asm/processor.h>
20 #include <asm/ucontext.h>
21 #include <asm/uaccess.h>
22 #include <arch/ptrace.h>
23 #include <arch/hwregs/cpu_vect.h>
25 extern unsigned long cris_signal_return_page;
28 * A syscall in CRIS is really a "break 13" instruction, which is 2
29 * bytes. The registers is manipulated so upon return the instruction
30 * will be executed again.
32 * This relies on that PC points to the instruction after the break call.
34 #define RESTART_CRIS_SYS(regs) regs->r10 = regs->orig_r10; regs->erp -= 2;
39 unsigned long extramask[_NSIG_WORDS - 1];
40 unsigned char retcode[8]; /* Trampoline code. */
43 struct rt_signal_frame {
44 struct siginfo *pinfo;
48 unsigned char retcode[8]; /* Trampoline code. */
51 void do_signal(int restart, struct pt_regs *regs);
52 void keep_debug_flags(unsigned long oldccs, unsigned long oldspc,
53 struct pt_regs *regs);
56 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
59 unsigned long old_usp;
61 /* Always make any pending restarted system calls return -EINTR */
62 current->restart_block.fn = do_no_restart_syscall;
65 * Restore the registers from &sc->regs. sc is already checked
66 * for VERIFY_READ since the signal_frame was previously
67 * checked in sys_sigreturn().
69 if (__copy_from_user(regs, sc, sizeof(struct pt_regs)))
72 /* Make that the user-mode flag is set. */
73 regs->ccs |= (1 << (U_CCS_BITNR + CCS_SHIFT));
75 /* Don't perform syscall restarting */
78 /* Restore the old USP. */
79 err |= __get_user(old_usp, &sc->usp);
88 asmlinkage int sys_sigreturn(void)
90 struct pt_regs *regs = current_pt_regs();
92 struct signal_frame __user *frame;
93 unsigned long oldspc = regs->spc;
94 unsigned long oldccs = regs->ccs;
96 frame = (struct signal_frame *) rdusp();
99 * Since the signal is stacked on a dword boundary, the frame
100 * should be dword aligned here as well. It it's not, then the
101 * user is trying some funny business.
103 if (((long)frame) & 3)
106 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
109 if (__get_user(set.sig[0], &frame->sc.oldmask) ||
110 (_NSIG_WORDS > 1 && __copy_from_user(&set.sig[1],
112 sizeof(frame->extramask))))
115 set_current_blocked(&set);
117 if (restore_sigcontext(regs, &frame->sc))
120 keep_debug_flags(oldccs, oldspc, regs);
125 force_sig(SIGSEGV, current);
129 asmlinkage int sys_rt_sigreturn(void)
131 struct pt_regs *regs = current_pt_regs();
133 struct rt_signal_frame __user *frame;
134 unsigned long oldspc = regs->spc;
135 unsigned long oldccs = regs->ccs;
137 frame = (struct rt_signal_frame *) rdusp();
140 * Since the signal is stacked on a dword boundary, the frame
141 * should be dword aligned here as well. It it's not, then the
142 * user is trying some funny business.
144 if (((long)frame) & 3)
147 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
150 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
153 set_current_blocked(&set);
155 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
158 if (restore_altstack(&frame->uc.uc_stack))
161 keep_debug_flags(oldccs, oldspc, regs);
166 force_sig(SIGSEGV, current);
170 /* Setup a signal frame. */
172 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
182 * Copy the registers. They are located first in sc, so it's
183 * possible to use sc directly.
185 err |= __copy_to_user(sc, regs, sizeof(struct pt_regs));
187 err |= __put_user(mask, &sc->oldmask);
188 err |= __put_user(usp, &sc->usp);
193 /* Figure out where to put the new signal frame - usually on the stack. */
194 static inline void __user *
195 get_sigframe(struct ksignal *ksig, size_t frame_size)
197 unsigned long sp = sigsp(rdusp(), ksig);
199 /* Make sure the frame is dword-aligned. */
202 return (void __user *)(sp - frame_size);
205 /* Grab and setup a signal frame.
207 * Basically a lot of state-info is stacked, and arranged for the
208 * user-mode program to return to the kernel using either a trampiline
209 * which performs the syscall sigreturn(), or a provided user-mode
213 setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
216 unsigned long return_ip;
217 struct signal_frame __user *frame;
220 frame = get_sigframe(ksig, sizeof(*frame));
222 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
225 err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
230 if (_NSIG_WORDS > 1) {
231 err |= __copy_to_user(frame->extramask, &set->sig[1],
232 sizeof(frame->extramask));
239 * Set up to return from user-space. If provided, use a stub
240 * already located in user-space.
242 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
243 return_ip = (unsigned long)ksig->ka.sa.sa_restorer;
245 /* Trampoline - the desired return ip is in the signal return page. */
246 return_ip = cris_signal_return_page;
249 * This is movu.w __NR_sigreturn, r9; break 13;
251 * WE DO NOT USE IT ANY MORE! It's only left here for historical
252 * reasons and because gdb uses it as a signature to notice
253 * signal handler stack frames.
255 err |= __put_user(0x9c5f, (short __user*)(frame->retcode+0));
256 err |= __put_user(__NR_sigreturn, (short __user*)(frame->retcode+2));
257 err |= __put_user(0xe93d, (short __user*)(frame->retcode+4));
264 * Set up registers for signal handler.
266 * Where the code enters now.
267 * Where the code enter later.
268 * First argument, signo.
270 regs->erp = (unsigned long) ksig->ka.sa.sa_handler;
271 regs->srp = return_ip;
272 regs->r10 = ksig->sig;
274 /* Actually move the USP to reflect the stacked frame. */
275 wrusp((unsigned long)frame);
281 setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
284 unsigned long return_ip;
285 struct rt_signal_frame __user *frame;
288 frame = get_sigframe(ksig, sizeof(*frame));
290 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
293 err |= __put_user(&frame->info, &frame->pinfo);
294 err |= __put_user(&frame->uc, &frame->puc);
295 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
300 /* Clear all the bits of the ucontext we don't use. */
301 err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
302 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
303 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
304 err |= __save_altstack(&frame->uc.uc_stack, rdusp());
310 * Set up to return from user-space. If provided, use a stub
311 * already located in user-space.
313 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
314 return_ip = (unsigned long) ksig->ka.sa.sa_restorer;
316 /* Trampoline - the desired return ip is in the signal return page. */
317 return_ip = cris_signal_return_page + 6;
320 * This is movu.w __NR_rt_sigreturn, r9; break 13;
322 * WE DO NOT USE IT ANY MORE! It's only left here for historical
323 * reasons and because gdb uses it as a signature to notice
324 * signal handler stack frames.
326 err |= __put_user(0x9c5f, (short __user*)(frame->retcode+0));
328 err |= __put_user(__NR_rt_sigreturn,
329 (short __user*)(frame->retcode+2));
331 err |= __put_user(0xe93d, (short __user*)(frame->retcode+4));
338 * Set up registers for signal handler.
340 * Where the code enters now.
341 * Where the code enters later.
342 * First argument is signo.
343 * Second argument is (siginfo_t *).
344 * Third argument is unused.
346 regs->erp = (unsigned long) ksig->ka.sa.sa_handler;
347 regs->srp = return_ip;
348 regs->r10 = ksig->sig;
349 regs->r11 = (unsigned long) &frame->info;
352 /* Actually move the usp to reflect the stacked frame. */
353 wrusp((unsigned long)frame);
358 /* Invoke a signal handler to, well, handle the signal. */
360 handle_signal(int canrestart, struct ksignal *ksig, struct pt_regs *regs)
362 sigset_t *oldset = sigmask_to_save();
365 /* Check if this got called from a system call. */
367 /* If so, check system call restarting. */
369 case -ERESTART_RESTARTBLOCK:
370 case -ERESTARTNOHAND:
372 * This means that the syscall should
373 * only be restarted if there was no
374 * handler for the signal, and since
375 * this point isn't reached unless
376 * there is a handler, there's no need
384 * This means restart the syscall if
385 * there is no handler, or the handler
386 * was registered with SA_RESTART.
388 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
395 case -ERESTARTNOINTR:
397 * This means that the syscall should
398 * be called again after the signal
401 RESTART_CRIS_SYS(regs);
406 /* Set up the stack frame. */
407 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
408 ret = setup_rt_frame(ksig, oldset, regs);
410 ret = setup_frame(ksig, oldset, regs);
412 signal_setup_done(ret, ksig, 0);
416 * Note that 'init' is a special process: it doesn't get signals it doesn't
417 * want to handle. Thus you cannot kill init even with a SIGKILL even by
420 * Also note that the regs structure given here as an argument, is the latest
421 * pushed pt_regs. It may or may not be the same as the first pushed registers
422 * when the initial usermode->kernelmode transition took place. Therefore
423 * we can use user_mode(regs) to see if we came directly from kernel or user
427 do_signal(int canrestart, struct pt_regs *regs)
431 canrestart = canrestart && ((int)regs->exs >= 0);
434 * The common case should go fast, which is why this point is
435 * reached from kernel-mode. If that's the case, just return
436 * without doing anything.
438 if (!user_mode(regs))
441 if (get_signal(&ksig)) {
442 /* Whee! Actually deliver the signal. */
443 handle_signal(canrestart, &ksig, regs);
447 /* Got here from a system call? */
449 /* Restart the system call - no handlers present. */
450 if (regs->r10 == -ERESTARTNOHAND ||
451 regs->r10 == -ERESTARTSYS ||
452 regs->r10 == -ERESTARTNOINTR) {
453 RESTART_CRIS_SYS(regs);
456 if (regs->r10 == -ERESTART_RESTARTBLOCK){
457 regs->r9 = __NR_restart_syscall;
462 /* if there's no signal to deliver, we just put the saved sigmask
464 restore_saved_sigmask();
468 ugdb_trap_user(struct thread_info *ti, int sig)
470 if (((user_regs(ti)->exs & 0xff00) >> 8) != SINGLE_STEP_INTR_VECT) {
471 /* Zero single-step PC if the reason we stopped wasn't a single
472 step exception. This is to avoid relying on it when it isn't
474 user_regs(ti)->spc = 0;
476 /* FIXME: Filter out false h/w breakpoint hits (i.e. EDA
477 not within any configured h/w breakpoint range). Synchronize with
478 what already exists for kernel debugging. */
479 if (((user_regs(ti)->exs & 0xff00) >> 8) == BREAK_8_INTR_VECT) {
480 /* Break 8: subtract 2 from ERP unless in a delay slot. */
481 if (!(user_regs(ti)->erp & 0x1))
482 user_regs(ti)->erp -= 2;
484 sys_kill(ti->task->pid, sig);
488 keep_debug_flags(unsigned long oldccs, unsigned long oldspc,
489 struct pt_regs *regs)
491 if (oldccs & (1 << Q_CCS_BITNR)) {
492 /* Pending single step due to single-stepping the break 13
493 in the signal trampoline: keep the Q flag. */
494 regs->ccs |= (1 << Q_CCS_BITNR);
495 /* S flag should be set - complain if it's not. */
496 if (!(oldccs & (1 << (S_CCS_BITNR + CCS_SHIFT)))) {
497 printk("Q flag but no S flag?");
499 regs->ccs |= (1 << (S_CCS_BITNR + CCS_SHIFT));
500 /* Assume the SPC is valid and interesting. */
503 } else if (oldccs & (1 << (S_CCS_BITNR + CCS_SHIFT))) {
504 /* If a h/w bp was set in the signal handler we need
505 to keep the S flag. */
506 regs->ccs |= (1 << (S_CCS_BITNR + CCS_SHIFT));
507 /* Don't keep the old SPC though; if we got here due to
508 a single-step, the Q flag should have been set. */
509 } else if (regs->spc) {
510 /* If we were single-stepping *before* the signal was taken,
511 we don't want to restore that state now, because GDB will
512 have forgotten all about it. */
514 regs->ccs &= ~(1 << (S_CCS_BITNR + CCS_SHIFT));
518 /* Set up the trampolines on the signal return page. */
520 cris_init_signal(void)
522 u16* data = kmalloc(PAGE_SIZE, GFP_KERNEL);
524 /* This is movu.w __NR_sigreturn, r9; break 13; */
526 data[1] = __NR_sigreturn;
528 /* This is movu.w __NR_rt_sigreturn, r9; break 13; */
530 data[4] = __NR_rt_sigreturn;
533 /* Map to userspace with appropriate permissions (no write access...) */
534 cris_signal_return_page = (unsigned long)
535 __ioremap_prot(virt_to_phys(data), PAGE_SIZE, PAGE_SIGNAL_TRAMPOLINE);
540 __initcall(cris_init_signal);