2 * arch/xtensa/kernel/signal.c
4 * Default platform functions.
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file "COPYING" in the main directory of this archive
10 * Copyright (C) 2005, 2006 Tensilica Inc.
11 * Copyright (C) 1991, 1992 Linus Torvalds
12 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
14 * Chris Zankel <chris@zankel.net>
15 * Joe Taylor <joe@tensilica.com>
18 #include <linux/signal.h>
19 #include <linux/errno.h>
20 #include <linux/ptrace.h>
21 #include <linux/personality.h>
22 #include <linux/freezer.h>
23 #include <linux/tracehook.h>
25 #include <asm/ucontext.h>
26 #include <asm/uaccess.h>
27 #include <asm/cacheflush.h>
28 #include <asm/coprocessor.h>
29 #include <asm/unistd.h>
33 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
35 extern struct task_struct *coproc_owners[];
44 #if XTENSA_HAVE_COPROCESSORS
45 xtregs_coprocessor_t cp;
48 unsigned char retcode[6];
49 unsigned int window[4];
53 * Flush register windows stored in pt_regs to stack.
54 * Returns 1 for errors.
58 flush_window_regs_user(struct pt_regs *regs)
60 const unsigned long ws = regs->windowstart;
61 const unsigned long wb = regs->windowbase;
67 /* Return if no other frames. */
72 /* Rotate windowmask and skip empty frames. */
74 wm = (ws >> wb) | (ws << (XCHAL_NUM_AREGS / 4 - wb));
75 base = (XCHAL_NUM_AREGS / 4) - (regs->wmask >> 4);
77 /* For call8 or call12 frames, we need the previous stack pointer. */
79 if ((regs->wmask & 2) == 0)
80 if (__get_user(sp, (int*)(regs->areg[base * 4 + 1] - 12)))
83 /* Spill frames to stack. */
85 while (base < XCHAL_NUM_AREGS / 4) {
90 /* Save registers a4..a7 (call8) or a4...a11 (call12) */
92 if (m & 2) { /* call4 */
95 } else if (m & 4) { /* call8 */
96 if (copy_to_user((void*)(sp - 32),
97 ®s->areg[(base + 1) * 4], 16))
101 } else if (m & 8) { /* call12 */
102 if (copy_to_user((void*)(sp - 48),
103 ®s->areg[(base + 1) * 4], 32))
108 /* Save current frame a0..a3 under next SP */
110 sp = regs->areg[((base + inc) * 4 + 1) % XCHAL_NUM_AREGS];
111 if (copy_to_user((void*)(sp - 16), ®s->areg[base * 4], 16))
114 /* Get current stack pointer for next loop iteration. */
116 sp = regs->areg[base * 4 + 1];
121 regs->windowstart = 1 << wb;
130 * Note: We don't copy double exception 'regs', we have to finish double exc.
131 * first before we return to signal handler! This dbl.exc.handler might cause
132 * another double exception, but I think we are fine as the situation is the
133 * same as if we had returned to the signal handerl and got an interrupt
138 setup_sigcontext(struct rt_sigframe __user *frame, struct pt_regs *regs)
140 struct sigcontext __user *sc = &frame->uc.uc_mcontext;
141 struct thread_info *ti = current_thread_info();
144 #define COPY(x) err |= __put_user(regs->x, &sc->sc_##x)
153 err |= flush_window_regs_user(regs);
154 err |= __copy_to_user (sc->sc_a, regs->areg, 16 * 4);
155 err |= __put_user(0, &sc->sc_xtregs);
160 #if XTENSA_HAVE_COPROCESSORS
161 coprocessor_flush_all(ti);
162 coprocessor_release_all(ti);
163 err |= __copy_to_user(&frame->xtregs.cp, &ti->xtregs_cp,
164 sizeof (frame->xtregs.cp));
166 err |= __copy_to_user(&frame->xtregs.opt, ®s->xtregs_opt,
167 sizeof (xtregs_opt_t));
168 err |= __copy_to_user(&frame->xtregs.user, &ti->xtregs_user,
169 sizeof (xtregs_user_t));
171 err |= __put_user(err ? NULL : &frame->xtregs, &sc->sc_xtregs);
177 restore_sigcontext(struct pt_regs *regs, struct rt_sigframe __user *frame)
179 struct sigcontext __user *sc = &frame->uc.uc_mcontext;
180 struct thread_info *ti = current_thread_info();
181 unsigned int err = 0;
184 #define COPY(x) err |= __get_user(regs->x, &sc->sc_##x)
192 /* All registers were flushed to stack. Start with a prestine frame. */
195 regs->windowbase = 0;
196 regs->windowstart = 1;
198 regs->syscall = -1; /* disable syscall checks */
200 /* For PS, restore only PS.CALLINC.
201 * Assume that all other bits are either the same as for the signal
202 * handler, or the user mode value doesn't matter (e.g. PS.OWB).
204 err |= __get_user(ps, &sc->sc_ps);
205 regs->ps = (regs->ps & ~PS_CALLINC_MASK) | (ps & PS_CALLINC_MASK);
207 /* Additional corruption checks */
209 if ((regs->lcount > 0)
210 && ((regs->lbeg > TASK_SIZE) || (regs->lend > TASK_SIZE)) )
213 err |= __copy_from_user(regs->areg, sc->sc_a, 16 * 4);
218 /* The signal handler may have used coprocessors in which
219 * case they are still enabled. We disable them to force a
220 * reloading of the original task's CP state by the lazy
221 * context-switching mechanisms of CP exception handling.
222 * Also, we essentially discard any coprocessor state that the
223 * signal handler created. */
225 #if XTENSA_HAVE_COPROCESSORS
226 coprocessor_release_all(ti);
227 err |= __copy_from_user(&ti->xtregs_cp, &frame->xtregs.cp,
228 sizeof (frame->xtregs.cp));
230 err |= __copy_from_user(&ti->xtregs_user, &frame->xtregs.user,
231 sizeof (xtregs_user_t));
232 err |= __copy_from_user(®s->xtregs_opt, &frame->xtregs.opt,
233 sizeof (xtregs_opt_t));
240 * Do a signal return; undo the signal stack.
243 asmlinkage long xtensa_rt_sigreturn(long a0, long a1, long a2, long a3,
244 long a4, long a5, struct pt_regs *regs)
246 struct rt_sigframe __user *frame;
250 /* Always make any pending restarted system calls return -EINTR */
251 current_thread_info()->restart_block.fn = do_no_restart_syscall;
254 panic("rt_sigreturn in double exception!\n");
256 frame = (struct rt_sigframe __user *) regs->areg[1];
258 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
261 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
264 sigdelsetmask(&set, ~_BLOCKABLE);
265 set_current_blocked(&set);
267 if (restore_sigcontext(regs, frame))
272 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->areg[1]) == -EFAULT)
278 force_sig(SIGSEGV, current);
285 * Set up a signal frame.
289 gen_return_code(unsigned char *codemem)
294 * The 12-bit immediate is really split up within the 24-bit MOVI
295 * instruction. As long as the above system call numbers fit within
296 * 8-bits, the following code works fine. See the Xtensa ISA for
300 #if __NR_rt_sigreturn > 255
301 # error Generating the MOVI instruction below breaks!
304 #ifdef __XTENSA_EB__ /* Big Endian version */
305 /* Generate instruction: MOVI a2, __NR_rt_sigreturn */
306 err |= __put_user(0x22, &codemem[0]);
307 err |= __put_user(0x0a, &codemem[1]);
308 err |= __put_user(__NR_rt_sigreturn, &codemem[2]);
309 /* Generate instruction: SYSCALL */
310 err |= __put_user(0x00, &codemem[3]);
311 err |= __put_user(0x05, &codemem[4]);
312 err |= __put_user(0x00, &codemem[5]);
314 #elif defined __XTENSA_EL__ /* Little Endian version */
315 /* Generate instruction: MOVI a2, __NR_rt_sigreturn */
316 err |= __put_user(0x22, &codemem[0]);
317 err |= __put_user(0xa0, &codemem[1]);
318 err |= __put_user(__NR_rt_sigreturn, &codemem[2]);
319 /* Generate instruction: SYSCALL */
320 err |= __put_user(0x00, &codemem[3]);
321 err |= __put_user(0x50, &codemem[4]);
322 err |= __put_user(0x00, &codemem[5]);
324 # error Must use compiler for Xtensa processors.
327 /* Flush generated code out of the data cache */
330 __invalidate_icache_range((unsigned long)codemem, 6UL);
331 __flush_invalidate_dcache_range((unsigned long)codemem, 6UL);
338 static int setup_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
339 sigset_t *set, struct pt_regs *regs)
341 struct rt_sigframe *frame;
344 unsigned long sp, ra;
348 if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! on_sig_stack(sp)) {
349 sp = current->sas_ss_sp + current->sas_ss_size;
352 frame = (void *)((sp - sizeof(*frame)) & -16ul);
355 panic ("Double exception sys_sigreturn\n");
357 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) {
361 signal = current_thread_info()->exec_domain
362 && current_thread_info()->exec_domain->signal_invmap
364 ? current_thread_info()->exec_domain->signal_invmap[sig]
367 if (ka->sa.sa_flags & SA_SIGINFO) {
368 err |= copy_siginfo_to_user(&frame->info, info);
371 /* Create the user context. */
373 err |= __put_user(0, &frame->uc.uc_flags);
374 err |= __put_user(0, &frame->uc.uc_link);
375 err |= __put_user((void *)current->sas_ss_sp,
376 &frame->uc.uc_stack.ss_sp);
377 err |= __put_user(sas_ss_flags(regs->areg[1]),
378 &frame->uc.uc_stack.ss_flags);
379 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
380 err |= setup_sigcontext(frame, regs);
381 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
383 if (ka->sa.sa_flags & SA_RESTORER) {
384 ra = (unsigned long)ka->sa.sa_restorer;
387 /* Create sys_rt_sigreturn syscall in stack frame */
389 err |= gen_return_code(frame->retcode);
394 ra = (unsigned long) frame->retcode;
398 * Create signal handler execution context.
399 * Return context not modified until this point.
402 /* Set up registers for signal handler */
403 start_thread(regs, (unsigned long) ka->sa.sa_handler,
404 (unsigned long) frame);
406 /* Set up a stack frame for a call4
407 * Note: PS.CALLINC is set to one by start_thread
409 regs->areg[4] = (((unsigned long) ra) & 0x3fffffff) | 0x40000000;
410 regs->areg[6] = (unsigned long) signal;
411 regs->areg[7] = (unsigned long) &frame->info;
412 regs->areg[8] = (unsigned long) &frame->uc;
414 /* Set access mode to USER_DS. Nomenclature is outdated, but
415 * functionality is used in uaccess.h
420 printk("SIG rt deliver (%s:%d): signal=%d sp=%p pc=%08x\n",
421 current->comm, current->pid, signal, frame, regs->pc);
427 force_sigsegv(sig, current);
431 asmlinkage long xtensa_sigaltstack(const stack_t __user *uss,
432 stack_t __user *uoss,
433 long a2, long a3, long a4, long a5,
434 struct pt_regs *regs)
436 return do_sigaltstack(uss, uoss, regs->areg[1]);
442 * Note that 'init' is a special process: it doesn't get signals it doesn't
443 * want to handle. Thus you cannot kill init even with a SIGKILL even by
446 * Note that we go through the signals twice: once to check the signals that
447 * the kernel can handle, and then we build all the user-level signal handling
448 * stack-frames in one go after that.
450 static void do_signal(struct pt_regs *regs)
454 struct k_sigaction ka;
460 if (test_thread_flag(TIF_RESTORE_SIGMASK))
461 oldset = ¤t->saved_sigmask;
463 oldset = ¤t->blocked;
465 task_pt_regs(current)->icountlevel = 0;
467 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
472 /* Are we from a system call? */
474 if ((signed)regs->syscall >= 0) {
476 /* If so, check system call restarting.. */
478 switch (regs->areg[2]) {
479 case -ERESTARTNOHAND:
480 case -ERESTART_RESTARTBLOCK:
481 regs->areg[2] = -EINTR;
485 if (!(ka.sa.sa_flags & SA_RESTART)) {
486 regs->areg[2] = -EINTR;
490 case -ERESTARTNOINTR:
491 regs->areg[2] = regs->syscall;
497 if (regs->areg[2] != 0)
502 /* Whee! Actually deliver the signal. */
503 /* Set up the stack frame */
504 ret = setup_frame(signr, &ka, &info, oldset, regs);
508 clear_thread_flag(TIF_RESTORE_SIGMASK);
509 block_sigmask(&ka, signr);
510 if (current->ptrace & PT_SINGLESTEP)
511 task_pt_regs(current)->icountlevel = 1;
517 /* Did we come from a system call? */
518 if ((signed) regs->syscall >= 0) {
519 /* Restart the system call - no handlers present */
520 switch (regs->areg[2]) {
521 case -ERESTARTNOHAND:
523 case -ERESTARTNOINTR:
524 regs->areg[2] = regs->syscall;
527 case -ERESTART_RESTARTBLOCK:
528 regs->areg[2] = __NR_restart_syscall;
534 /* If there's no signal to deliver, we just restore the saved mask. */
535 restore_saved_sigmask();
537 if (current->ptrace & PT_SINGLESTEP)
538 task_pt_regs(current)->icountlevel = 1;
542 void do_notify_resume(struct pt_regs *regs)
544 if (!user_mode(regs))
547 if (test_thread_flag(TIF_SIGPENDING))
550 if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
551 tracehook_notify_resume(regs);