Adding support for MOXA ART SoC. Testing port of linux-2.6.32.60-moxart.
[linux-3.6.7-moxart.git] / arch / xtensa / kernel / signal.c
blobefe4e854b3cdd06808eec1bcd3fe8fa70b07ed96
1 /*
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
8 * for more details.
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>
31 #define DEBUG_SIG 0
33 extern struct task_struct *coproc_owners[];
35 struct rt_sigframe
37 struct siginfo info;
38 struct ucontext uc;
39 struct {
40 xtregs_opt_t opt;
41 xtregs_user_t user;
42 #if XTENSA_HAVE_COPROCESSORS
43 xtregs_coprocessor_t cp;
44 #endif
45 } xtregs;
46 unsigned char retcode[6];
47 unsigned int window[4];
50 /*
51 * Flush register windows stored in pt_regs to stack.
52 * Returns 1 for errors.
55 int
56 flush_window_regs_user(struct pt_regs *regs)
58 const unsigned long ws = regs->windowstart;
59 const unsigned long wb = regs->windowbase;
60 unsigned long sp = 0;
61 unsigned long wm;
62 int err = 1;
63 int base;
65 /* Return if no other frames. */
67 if (regs->wmask == 1)
68 return 0;
70 /* Rotate windowmask and skip empty frames. */
72 wm = (ws >> wb) | (ws << (XCHAL_NUM_AREGS / 4 - wb));
73 base = (XCHAL_NUM_AREGS / 4) - (regs->wmask >> 4);
75 /* For call8 or call12 frames, we need the previous stack pointer. */
77 if ((regs->wmask & 2) == 0)
78 if (__get_user(sp, (int*)(regs->areg[base * 4 + 1] - 12)))
79 goto errout;
81 /* Spill frames to stack. */
83 while (base < XCHAL_NUM_AREGS / 4) {
85 int m = (wm >> base);
86 int inc = 0;
88 /* Save registers a4..a7 (call8) or a4...a11 (call12) */
90 if (m & 2) { /* call4 */
91 inc = 1;
93 } else if (m & 4) { /* call8 */
94 if (copy_to_user((void*)(sp - 32),
95 &regs->areg[(base + 1) * 4], 16))
96 goto errout;
97 inc = 2;
99 } else if (m & 8) { /* call12 */
100 if (copy_to_user((void*)(sp - 48),
101 &regs->areg[(base + 1) * 4], 32))
102 goto errout;
103 inc = 3;
106 /* Save current frame a0..a3 under next SP */
108 sp = regs->areg[((base + inc) * 4 + 1) % XCHAL_NUM_AREGS];
109 if (copy_to_user((void*)(sp - 16), &regs->areg[base * 4], 16))
110 goto errout;
112 /* Get current stack pointer for next loop iteration. */
114 sp = regs->areg[base * 4 + 1];
115 base += inc;
118 regs->wmask = 1;
119 regs->windowstart = 1 << wb;
121 return 0;
123 errout:
124 return err;
128 * Note: We don't copy double exception 'regs', we have to finish double exc.
129 * first before we return to signal handler! This dbl.exc.handler might cause
130 * another double exception, but I think we are fine as the situation is the
131 * same as if we had returned to the signal handerl and got an interrupt
132 * immediately...
135 static int
136 setup_sigcontext(struct rt_sigframe __user *frame, struct pt_regs *regs)
138 struct sigcontext __user *sc = &frame->uc.uc_mcontext;
139 struct thread_info *ti = current_thread_info();
140 int err = 0;
142 #define COPY(x) err |= __put_user(regs->x, &sc->sc_##x)
143 COPY(pc);
144 COPY(ps);
145 COPY(lbeg);
146 COPY(lend);
147 COPY(lcount);
148 COPY(sar);
149 #undef COPY
151 err |= flush_window_regs_user(regs);
152 err |= __copy_to_user (sc->sc_a, regs->areg, 16 * 4);
153 err |= __put_user(0, &sc->sc_xtregs);
155 if (err)
156 return err;
158 #if XTENSA_HAVE_COPROCESSORS
159 coprocessor_flush_all(ti);
160 coprocessor_release_all(ti);
161 err |= __copy_to_user(&frame->xtregs.cp, &ti->xtregs_cp,
162 sizeof (frame->xtregs.cp));
163 #endif
164 err |= __copy_to_user(&frame->xtregs.opt, &regs->xtregs_opt,
165 sizeof (xtregs_opt_t));
166 err |= __copy_to_user(&frame->xtregs.user, &ti->xtregs_user,
167 sizeof (xtregs_user_t));
169 err |= __put_user(err ? NULL : &frame->xtregs, &sc->sc_xtregs);
171 return err;
174 static int
175 restore_sigcontext(struct pt_regs *regs, struct rt_sigframe __user *frame)
177 struct sigcontext __user *sc = &frame->uc.uc_mcontext;
178 struct thread_info *ti = current_thread_info();
179 unsigned int err = 0;
180 unsigned long ps;
182 #define COPY(x) err |= __get_user(regs->x, &sc->sc_##x)
183 COPY(pc);
184 COPY(lbeg);
185 COPY(lend);
186 COPY(lcount);
187 COPY(sar);
188 #undef COPY
190 /* All registers were flushed to stack. Start with a prestine frame. */
192 regs->wmask = 1;
193 regs->windowbase = 0;
194 regs->windowstart = 1;
196 regs->syscall = -1; /* disable syscall checks */
198 /* For PS, restore only PS.CALLINC.
199 * Assume that all other bits are either the same as for the signal
200 * handler, or the user mode value doesn't matter (e.g. PS.OWB).
202 err |= __get_user(ps, &sc->sc_ps);
203 regs->ps = (regs->ps & ~PS_CALLINC_MASK) | (ps & PS_CALLINC_MASK);
205 /* Additional corruption checks */
207 if ((regs->lcount > 0)
208 && ((regs->lbeg > TASK_SIZE) || (regs->lend > TASK_SIZE)) )
209 err = 1;
211 err |= __copy_from_user(regs->areg, sc->sc_a, 16 * 4);
213 if (err)
214 return err;
216 /* The signal handler may have used coprocessors in which
217 * case they are still enabled. We disable them to force a
218 * reloading of the original task's CP state by the lazy
219 * context-switching mechanisms of CP exception handling.
220 * Also, we essentially discard any coprocessor state that the
221 * signal handler created. */
223 #if XTENSA_HAVE_COPROCESSORS
224 coprocessor_release_all(ti);
225 err |= __copy_from_user(&ti->xtregs_cp, &frame->xtregs.cp,
226 sizeof (frame->xtregs.cp));
227 #endif
228 err |= __copy_from_user(&ti->xtregs_user, &frame->xtregs.user,
229 sizeof (xtregs_user_t));
230 err |= __copy_from_user(&regs->xtregs_opt, &frame->xtregs.opt,
231 sizeof (xtregs_opt_t));
233 return err;
238 * Do a signal return; undo the signal stack.
241 asmlinkage long xtensa_rt_sigreturn(long a0, long a1, long a2, long a3,
242 long a4, long a5, struct pt_regs *regs)
244 struct rt_sigframe __user *frame;
245 sigset_t set;
246 int ret;
248 /* Always make any pending restarted system calls return -EINTR */
249 current_thread_info()->restart_block.fn = do_no_restart_syscall;
251 if (regs->depc > 64)
252 panic("rt_sigreturn in double exception!\n");
254 frame = (struct rt_sigframe __user *) regs->areg[1];
256 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
257 goto badframe;
259 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
260 goto badframe;
262 set_current_blocked(&set);
264 if (restore_sigcontext(regs, frame))
265 goto badframe;
267 ret = regs->areg[2];
269 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->areg[1]) == -EFAULT)
270 goto badframe;
272 return ret;
274 badframe:
275 force_sig(SIGSEGV, current);
276 return 0;
282 * Set up a signal frame.
285 static int
286 gen_return_code(unsigned char *codemem)
288 int err = 0;
291 * The 12-bit immediate is really split up within the 24-bit MOVI
292 * instruction. As long as the above system call numbers fit within
293 * 8-bits, the following code works fine. See the Xtensa ISA for
294 * details.
297 #if __NR_rt_sigreturn > 255
298 # error Generating the MOVI instruction below breaks!
299 #endif
301 #ifdef __XTENSA_EB__ /* Big Endian version */
302 /* Generate instruction: MOVI a2, __NR_rt_sigreturn */
303 err |= __put_user(0x22, &codemem[0]);
304 err |= __put_user(0x0a, &codemem[1]);
305 err |= __put_user(__NR_rt_sigreturn, &codemem[2]);
306 /* Generate instruction: SYSCALL */
307 err |= __put_user(0x00, &codemem[3]);
308 err |= __put_user(0x05, &codemem[4]);
309 err |= __put_user(0x00, &codemem[5]);
311 #elif defined __XTENSA_EL__ /* Little Endian version */
312 /* Generate instruction: MOVI a2, __NR_rt_sigreturn */
313 err |= __put_user(0x22, &codemem[0]);
314 err |= __put_user(0xa0, &codemem[1]);
315 err |= __put_user(__NR_rt_sigreturn, &codemem[2]);
316 /* Generate instruction: SYSCALL */
317 err |= __put_user(0x00, &codemem[3]);
318 err |= __put_user(0x50, &codemem[4]);
319 err |= __put_user(0x00, &codemem[5]);
320 #else
321 # error Must use compiler for Xtensa processors.
322 #endif
324 /* Flush generated code out of the data cache */
326 if (err == 0) {
327 __invalidate_icache_range((unsigned long)codemem, 6UL);
328 __flush_invalidate_dcache_range((unsigned long)codemem, 6UL);
331 return err;
335 static int setup_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
336 sigset_t *set, struct pt_regs *regs)
338 struct rt_sigframe *frame;
339 int err = 0;
340 int signal;
341 unsigned long sp, ra;
343 sp = regs->areg[1];
345 if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! on_sig_stack(sp)) {
346 sp = current->sas_ss_sp + current->sas_ss_size;
349 frame = (void *)((sp - sizeof(*frame)) & -16ul);
351 if (regs->depc > 64)
352 panic ("Double exception sys_sigreturn\n");
354 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) {
355 goto give_sigsegv;
358 signal = current_thread_info()->exec_domain
359 && current_thread_info()->exec_domain->signal_invmap
360 && sig < 32
361 ? current_thread_info()->exec_domain->signal_invmap[sig]
362 : sig;
364 if (ka->sa.sa_flags & SA_SIGINFO) {
365 err |= copy_siginfo_to_user(&frame->info, info);
368 /* Create the user context. */
370 err |= __put_user(0, &frame->uc.uc_flags);
371 err |= __put_user(0, &frame->uc.uc_link);
372 err |= __put_user((void *)current->sas_ss_sp,
373 &frame->uc.uc_stack.ss_sp);
374 err |= __put_user(sas_ss_flags(regs->areg[1]),
375 &frame->uc.uc_stack.ss_flags);
376 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
377 err |= setup_sigcontext(frame, regs);
378 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
380 if (ka->sa.sa_flags & SA_RESTORER) {
381 ra = (unsigned long)ka->sa.sa_restorer;
382 } else {
384 /* Create sys_rt_sigreturn syscall in stack frame */
386 err |= gen_return_code(frame->retcode);
388 if (err) {
389 goto give_sigsegv;
391 ra = (unsigned long) frame->retcode;
395 * Create signal handler execution context.
396 * Return context not modified until this point.
399 /* Set up registers for signal handler */
400 start_thread(regs, (unsigned long) ka->sa.sa_handler,
401 (unsigned long) frame);
403 /* Set up a stack frame for a call4
404 * Note: PS.CALLINC is set to one by start_thread
406 regs->areg[4] = (((unsigned long) ra) & 0x3fffffff) | 0x40000000;
407 regs->areg[6] = (unsigned long) signal;
408 regs->areg[7] = (unsigned long) &frame->info;
409 regs->areg[8] = (unsigned long) &frame->uc;
411 /* Set access mode to USER_DS. Nomenclature is outdated, but
412 * functionality is used in uaccess.h
414 set_fs(USER_DS);
416 #if DEBUG_SIG
417 printk("SIG rt deliver (%s:%d): signal=%d sp=%p pc=%08x\n",
418 current->comm, current->pid, signal, frame, regs->pc);
419 #endif
421 return 0;
423 give_sigsegv:
424 force_sigsegv(sig, current);
425 return -EFAULT;
428 asmlinkage long xtensa_sigaltstack(const stack_t __user *uss,
429 stack_t __user *uoss,
430 long a2, long a3, long a4, long a5,
431 struct pt_regs *regs)
433 return do_sigaltstack(uss, uoss, regs->areg[1]);
439 * Note that 'init' is a special process: it doesn't get signals it doesn't
440 * want to handle. Thus you cannot kill init even with a SIGKILL even by
441 * mistake.
443 * Note that we go through the signals twice: once to check the signals that
444 * the kernel can handle, and then we build all the user-level signal handling
445 * stack-frames in one go after that.
447 static void do_signal(struct pt_regs *regs)
449 siginfo_t info;
450 int signr;
451 struct k_sigaction ka;
453 task_pt_regs(current)->icountlevel = 0;
455 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
457 if (signr > 0) {
458 int ret;
460 /* Are we from a system call? */
462 if ((signed)regs->syscall >= 0) {
464 /* If so, check system call restarting.. */
466 switch (regs->areg[2]) {
467 case -ERESTARTNOHAND:
468 case -ERESTART_RESTARTBLOCK:
469 regs->areg[2] = -EINTR;
470 break;
472 case -ERESTARTSYS:
473 if (!(ka.sa.sa_flags & SA_RESTART)) {
474 regs->areg[2] = -EINTR;
475 break;
477 /* fallthrough */
478 case -ERESTARTNOINTR:
479 regs->areg[2] = regs->syscall;
480 regs->pc -= 3;
481 break;
483 default:
484 /* nothing to do */
485 if (regs->areg[2] != 0)
486 break;
490 /* Whee! Actually deliver the signal. */
491 /* Set up the stack frame */
492 ret = setup_frame(signr, &ka, &info, sigmask_to_save(), regs);
493 if (ret)
494 return;
496 signal_delivered(signr, &info, &ka, regs, 0);
497 if (current->ptrace & PT_SINGLESTEP)
498 task_pt_regs(current)->icountlevel = 1;
500 return;
503 /* Did we come from a system call? */
504 if ((signed) regs->syscall >= 0) {
505 /* Restart the system call - no handlers present */
506 switch (regs->areg[2]) {
507 case -ERESTARTNOHAND:
508 case -ERESTARTSYS:
509 case -ERESTARTNOINTR:
510 regs->areg[2] = regs->syscall;
511 regs->pc -= 3;
512 break;
513 case -ERESTART_RESTARTBLOCK:
514 regs->areg[2] = __NR_restart_syscall;
515 regs->pc -= 3;
516 break;
520 /* If there's no signal to deliver, we just restore the saved mask. */
521 restore_saved_sigmask();
523 if (current->ptrace & PT_SINGLESTEP)
524 task_pt_regs(current)->icountlevel = 1;
525 return;
528 void do_notify_resume(struct pt_regs *regs)
530 if (!user_mode(regs))
531 return;
533 if (test_thread_flag(TIF_SIGPENDING))
534 do_signal(regs);
536 if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
537 tracehook_notify_resume(regs);