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 /* Restore the old USP. */
76 err |= __get_user(old_usp, &sc->usp);
85 asmlinkage int sys_sigreturn(void)
87 struct pt_regs *regs = current_pt_regs();
89 struct signal_frame __user *frame;
90 unsigned long oldspc = regs->spc;
91 unsigned long oldccs = regs->ccs;
93 frame = (struct signal_frame *) rdusp();
96 * Since the signal is stacked on a dword boundary, the frame
97 * should be dword aligned here as well. It it's not, then the
98 * user is trying some funny business.
100 if (((long)frame) & 3)
103 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
106 if (__get_user(set.sig[0], &frame->sc.oldmask) ||
107 (_NSIG_WORDS > 1 && __copy_from_user(&set.sig[1],
109 sizeof(frame->extramask))))
112 set_current_blocked(&set);
114 if (restore_sigcontext(regs, &frame->sc))
117 keep_debug_flags(oldccs, oldspc, regs);
122 force_sig(SIGSEGV, current);
126 asmlinkage int sys_rt_sigreturn(void)
128 struct pt_regs *regs = current_pt_regs();
130 struct rt_signal_frame __user *frame;
131 unsigned long oldspc = regs->spc;
132 unsigned long oldccs = regs->ccs;
134 frame = (struct rt_signal_frame *) rdusp();
137 * Since the signal is stacked on a dword boundary, the frame
138 * should be dword aligned here as well. It it's not, then the
139 * user is trying some funny business.
141 if (((long)frame) & 3)
144 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
147 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
150 set_current_blocked(&set);
152 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
155 if (restore_altstack(&frame->uc.uc_stack))
158 keep_debug_flags(oldccs, oldspc, regs);
163 force_sig(SIGSEGV, current);
167 /* Setup a signal frame. */
169 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
179 * Copy the registers. They are located first in sc, so it's
180 * possible to use sc directly.
182 err |= __copy_to_user(sc, regs, sizeof(struct pt_regs));
184 err |= __put_user(mask, &sc->oldmask);
185 err |= __put_user(usp, &sc->usp);
190 /* Figure out where to put the new signal frame - usually on the stack. */
191 static inline void __user *
192 get_sigframe(struct ksignal *ksig, size_t frame_size)
194 unsigned long sp = sigsp(rdusp(), ksig);
196 /* Make sure the frame is dword-aligned. */
199 return (void __user *)(sp - frame_size);
202 /* Grab and setup a signal frame.
204 * Basically a lot of state-info is stacked, and arranged for the
205 * user-mode program to return to the kernel using either a trampiline
206 * which performs the syscall sigreturn(), or a provided user-mode
210 setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
213 unsigned long return_ip;
214 struct signal_frame __user *frame;
217 frame = get_sigframe(ksig, sizeof(*frame));
219 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
222 err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
227 if (_NSIG_WORDS > 1) {
228 err |= __copy_to_user(frame->extramask, &set->sig[1],
229 sizeof(frame->extramask));
236 * Set up to return from user-space. If provided, use a stub
237 * already located in user-space.
239 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
240 return_ip = (unsigned long)ksig->ka.sa.sa_restorer;
242 /* Trampoline - the desired return ip is in the signal return page. */
243 return_ip = cris_signal_return_page;
246 * This is movu.w __NR_sigreturn, r9; break 13;
248 * WE DO NOT USE IT ANY MORE! It's only left here for historical
249 * reasons and because gdb uses it as a signature to notice
250 * signal handler stack frames.
252 err |= __put_user(0x9c5f, (short __user*)(frame->retcode+0));
253 err |= __put_user(__NR_sigreturn, (short __user*)(frame->retcode+2));
254 err |= __put_user(0xe93d, (short __user*)(frame->retcode+4));
261 * Set up registers for signal handler.
263 * Where the code enters now.
264 * Where the code enter later.
265 * First argument, signo.
267 regs->erp = (unsigned long) ksig->ka.sa.sa_handler;
268 regs->srp = return_ip;
269 regs->r10 = ksig->sig;
271 /* Actually move the USP to reflect the stacked frame. */
272 wrusp((unsigned long)frame);
278 setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
281 unsigned long return_ip;
282 struct rt_signal_frame __user *frame;
285 frame = get_sigframe(ksig, sizeof(*frame));
287 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
290 err |= __put_user(&frame->info, &frame->pinfo);
291 err |= __put_user(&frame->uc, &frame->puc);
292 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
297 /* Clear all the bits of the ucontext we don't use. */
298 err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
299 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
300 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
301 err |= __save_altstack(&frame->uc.uc_stack, rdusp());
307 * Set up to return from user-space. If provided, use a stub
308 * already located in user-space.
310 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
311 return_ip = (unsigned long) ksig->ka.sa.sa_restorer;
313 /* Trampoline - the desired return ip is in the signal return page. */
314 return_ip = cris_signal_return_page + 6;
317 * This is movu.w __NR_rt_sigreturn, r9; break 13;
319 * WE DO NOT USE IT ANY MORE! It's only left here for historical
320 * reasons and because gdb uses it as a signature to notice
321 * signal handler stack frames.
323 err |= __put_user(0x9c5f, (short __user*)(frame->retcode+0));
325 err |= __put_user(__NR_rt_sigreturn,
326 (short __user*)(frame->retcode+2));
328 err |= __put_user(0xe93d, (short __user*)(frame->retcode+4));
335 * Set up registers for signal handler.
337 * Where the code enters now.
338 * Where the code enters later.
339 * First argument is signo.
340 * Second argument is (siginfo_t *).
341 * Third argument is unused.
343 regs->erp = (unsigned long) ksig->ka.sa.sa_handler;
344 regs->srp = return_ip;
345 regs->r10 = ksig->sig;
346 regs->r11 = (unsigned long) &frame->info;
349 /* Actually move the usp to reflect the stacked frame. */
350 wrusp((unsigned long)frame);
355 /* Invoke a signal handler to, well, handle the signal. */
357 handle_signal(int canrestart, struct ksignal *ksig, struct pt_regs *regs)
359 sigset_t *oldset = sigmask_to_save();
362 /* Check if this got called from a system call. */
364 /* If so, check system call restarting. */
366 case -ERESTART_RESTARTBLOCK:
367 case -ERESTARTNOHAND:
369 * This means that the syscall should
370 * only be restarted if there was no
371 * handler for the signal, and since
372 * this point isn't reached unless
373 * there is a handler, there's no need
381 * This means restart the syscall if
382 * there is no handler, or the handler
383 * was registered with SA_RESTART.
385 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
392 case -ERESTARTNOINTR:
394 * This means that the syscall should
395 * be called again after the signal
398 RESTART_CRIS_SYS(regs);
403 /* Set up the stack frame. */
404 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
405 ret = setup_rt_frame(ksig, oldset, regs);
407 ret = setup_frame(ksig, oldset, regs);
409 signal_setup_done(ret, ksig, 0);
413 * Note that 'init' is a special process: it doesn't get signals it doesn't
414 * want to handle. Thus you cannot kill init even with a SIGKILL even by
417 * Also note that the regs structure given here as an argument, is the latest
418 * pushed pt_regs. It may or may not be the same as the first pushed registers
419 * when the initial usermode->kernelmode transition took place. Therefore
420 * we can use user_mode(regs) to see if we came directly from kernel or user
424 do_signal(int canrestart, struct pt_regs *regs)
429 * The common case should go fast, which is why this point is
430 * reached from kernel-mode. If that's the case, just return
431 * without doing anything.
433 if (!user_mode(regs))
436 if (get_signal(&ksig)) {
437 /* Whee! Actually deliver the signal. */
438 handle_signal(canrestart, &ksig, regs);
442 /* Got here 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);
451 if (regs->r10 == -ERESTART_RESTARTBLOCK){
452 regs->r9 = __NR_restart_syscall;
457 /* if there's no signal to deliver, we just put the saved sigmask
459 restore_saved_sigmask();
463 ugdb_trap_user(struct thread_info *ti, int sig)
465 if (((user_regs(ti)->exs & 0xff00) >> 8) != SINGLE_STEP_INTR_VECT) {
466 /* Zero single-step PC if the reason we stopped wasn't a single
467 step exception. This is to avoid relying on it when it isn't
469 user_regs(ti)->spc = 0;
471 /* FIXME: Filter out false h/w breakpoint hits (i.e. EDA
472 not within any configured h/w breakpoint range). Synchronize with
473 what already exists for kernel debugging. */
474 if (((user_regs(ti)->exs & 0xff00) >> 8) == BREAK_8_INTR_VECT) {
475 /* Break 8: subtract 2 from ERP unless in a delay slot. */
476 if (!(user_regs(ti)->erp & 0x1))
477 user_regs(ti)->erp -= 2;
479 sys_kill(ti->task->pid, sig);
483 keep_debug_flags(unsigned long oldccs, unsigned long oldspc,
484 struct pt_regs *regs)
486 if (oldccs & (1 << Q_CCS_BITNR)) {
487 /* Pending single step due to single-stepping the break 13
488 in the signal trampoline: keep the Q flag. */
489 regs->ccs |= (1 << Q_CCS_BITNR);
490 /* S flag should be set - complain if it's not. */
491 if (!(oldccs & (1 << (S_CCS_BITNR + CCS_SHIFT)))) {
492 printk("Q flag but no S flag?");
494 regs->ccs |= (1 << (S_CCS_BITNR + CCS_SHIFT));
495 /* Assume the SPC is valid and interesting. */
498 } else if (oldccs & (1 << (S_CCS_BITNR + CCS_SHIFT))) {
499 /* If a h/w bp was set in the signal handler we need
500 to keep the S flag. */
501 regs->ccs |= (1 << (S_CCS_BITNR + CCS_SHIFT));
502 /* Don't keep the old SPC though; if we got here due to
503 a single-step, the Q flag should have been set. */
504 } else if (regs->spc) {
505 /* If we were single-stepping *before* the signal was taken,
506 we don't want to restore that state now, because GDB will
507 have forgotten all about it. */
509 regs->ccs &= ~(1 << (S_CCS_BITNR + CCS_SHIFT));
513 /* Set up the trampolines on the signal return page. */
515 cris_init_signal(void)
517 u16* data = kmalloc(PAGE_SIZE, GFP_KERNEL);
519 /* This is movu.w __NR_sigreturn, r9; break 13; */
521 data[1] = __NR_sigreturn;
523 /* This is movu.w __NR_rt_sigreturn, r9; break 13; */
525 data[4] = __NR_rt_sigreturn;
528 /* Map to userspace with appropriate permissions (no write access...) */
529 cris_signal_return_page = (unsigned long)
530 __ioremap_prot(virt_to_phys(data), PAGE_SIZE, PAGE_SIGNAL_TRAMPOLINE);
535 __initcall(cris_init_signal);