1/*
  2 * This file is subject to the terms and conditions of the GNU General Public
  3 * License.  See the file "COPYING" in the main directory of this archive
  4 * for more details.
  5 *
  6 * Copyright (C) 1991, 1992  Linus Torvalds
  7 * Copyright (C) 1994 - 2000  Ralf Baechle
  8 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
  9 * Copyright (C) 2014, Imagination Technologies Ltd.
 10 */
 11#include <linux/cache.h>
 12#include <linux/context_tracking.h>
 13#include <linux/irqflags.h>
 14#include <linux/sched.h>
 15#include <linux/mm.h>
 16#include <linux/personality.h>
 17#include <linux/smp.h>
 18#include <linux/kernel.h>
 19#include <linux/signal.h>
 20#include <linux/errno.h>
 21#include <linux/wait.h>
 22#include <linux/ptrace.h>
 23#include <linux/unistd.h>
 24#include <linux/uprobes.h>
 25#include <linux/compiler.h>
 26#include <linux/syscalls.h>
 27#include <linux/uaccess.h>
 28#include <linux/resume_user_mode.h>
 29
 30#include <asm/abi.h>
 31#include <asm/asm.h>
 32#include <linux/bitops.h>
 33#include <asm/cacheflush.h>
 34#include <asm/fpu.h>
 35#include <asm/sim.h>
 36#include <asm/ucontext.h>
 37#include <asm/cpu-features.h>
 38#include <asm/dsp.h>
 39#include <asm/inst.h>
 40#include <asm/msa.h>
 41
 42#include "signal-common.h"
 43
 44static int (*save_fp_context)(void __user *sc);
 45static int (*restore_fp_context)(void __user *sc);
 
 
 
 
 
 
 46
 47struct sigframe {
 48	u32 sf_ass[4];		/* argument save space for o32 */
 49	u32 sf_pad[2];		/* Was: signal trampoline */
 50
 51	/* Matches struct ucontext from its uc_mcontext field onwards */
 52	struct sigcontext sf_sc;
 53	sigset_t sf_mask;
 54	unsigned long long sf_extcontext[];
 55};
 56
 57struct rt_sigframe {
 58	u32 rs_ass[4];		/* argument save space for o32 */
 59	u32 rs_pad[2];		/* Was: signal trampoline */
 60	struct siginfo rs_info;
 61	struct ucontext rs_uc;
 62};
 63
 64#ifdef CONFIG_MIPS_FP_SUPPORT
 65
 66/*
 67 * Thread saved context copy to/from a signal context presumed to be on the
 68 * user stack, and therefore accessed with appropriate macros from uaccess.h.
 69 */
 70static int copy_fp_to_sigcontext(void __user *sc)
 71{
 72	struct mips_abi *abi = current->thread.abi;
 73	uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
 74	uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
 75	int i;
 76	int err = 0;
 77	int inc = test_thread_flag(TIF_32BIT_FPREGS) ? 2 : 1;
 78
 79	for (i = 0; i < NUM_FPU_REGS; i += inc) {
 80		err |=
 81		    __put_user(get_fpr64(&current->thread.fpu.fpr[i], 0),
 82			       &fpregs[i]);
 83	}
 84	err |= __put_user(current->thread.fpu.fcr31, csr);
 85
 86	return err;
 87}
 88
 89static int copy_fp_from_sigcontext(void __user *sc)
 90{
 91	struct mips_abi *abi = current->thread.abi;
 92	uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
 93	uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
 94	int i;
 95	int err = 0;
 96	int inc = test_thread_flag(TIF_32BIT_FPREGS) ? 2 : 1;
 97	u64 fpr_val;
 98
 99	for (i = 0; i < NUM_FPU_REGS; i += inc) {
100		err |= __get_user(fpr_val, &fpregs[i]);
101		set_fpr64(&current->thread.fpu.fpr[i], 0, fpr_val);
102	}
103	err |= __get_user(current->thread.fpu.fcr31, csr);
104
105	return err;
106}
107
108#else /* !CONFIG_MIPS_FP_SUPPORT */
109
110static int copy_fp_to_sigcontext(void __user *sc)
111{
112	return 0;
113}
114
115static int copy_fp_from_sigcontext(void __user *sc)
116{
117	return 0;
118}
119
120#endif /* !CONFIG_MIPS_FP_SUPPORT */
121
122/*
123 * Wrappers for the assembly _{save,restore}_fp_context functions.
124 */
125static int save_hw_fp_context(void __user *sc)
126{
127	struct mips_abi *abi = current->thread.abi;
128	uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
129	uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
130
131	return _save_fp_context(fpregs, csr);
132}
133
134static int restore_hw_fp_context(void __user *sc)
135{
136	struct mips_abi *abi = current->thread.abi;
137	uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
138	uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
139
140	return _restore_fp_context(fpregs, csr);
141}
142
143/*
144 * Extended context handling.
145 */
146
147static inline void __user *sc_to_extcontext(void __user *sc)
148{
149	struct ucontext __user *uc;
150
151	/*
152	 * We can just pretend the sigcontext is always embedded in a struct
153	 * ucontext here, because the offset from sigcontext to extended
154	 * context is the same in the struct sigframe case.
155	 */
156	uc = container_of(sc, struct ucontext, uc_mcontext);
157	return &uc->uc_extcontext;
158}
159
160#ifdef CONFIG_CPU_HAS_MSA
161
162static int save_msa_extcontext(void __user *buf)
163{
164	struct msa_extcontext __user *msa = buf;
165	uint64_t val;
166	int i, err;
167
168	if (!thread_msa_context_live())
169		return 0;
170
171	/*
172	 * Ensure that we can't lose the live MSA context between checking
173	 * for it & writing it to memory.
174	 */
175	preempt_disable();
176
177	if (is_msa_enabled()) {
178		/*
179		 * There are no EVA versions of the vector register load/store
180		 * instructions, so MSA context has to be saved to kernel memory
181		 * and then copied to user memory. The save to kernel memory
182		 * should already have been done when handling scalar FP
183		 * context.
184		 */
185		BUG_ON(IS_ENABLED(CONFIG_EVA));
186
187		err = __put_user(read_msa_csr(), &msa->csr);
188		err |= _save_msa_all_upper(&msa->wr);
189
190		preempt_enable();
191	} else {
192		preempt_enable();
193
194		err = __put_user(current->thread.fpu.msacsr, &msa->csr);
195
196		for (i = 0; i < NUM_FPU_REGS; i++) {
197			val = get_fpr64(&current->thread.fpu.fpr[i], 1);
198			err |= __put_user(val, &msa->wr[i]);
199		}
200	}
201
202	err |= __put_user(MSA_EXTCONTEXT_MAGIC, &msa->ext.magic);
203	err |= __put_user(sizeof(*msa), &msa->ext.size);
204
205	return err ? -EFAULT : sizeof(*msa);
206}
207
208static int restore_msa_extcontext(void __user *buf, unsigned int size)
209{
210	struct msa_extcontext __user *msa = buf;
211	unsigned long long val;
212	unsigned int csr;
213	int i, err;
214
215	if (size != sizeof(*msa))
216		return -EINVAL;
217
218	err = get_user(csr, &msa->csr);
219	if (err)
220		return err;
221
222	preempt_disable();
223
224	if (is_msa_enabled()) {
225		/*
226		 * There are no EVA versions of the vector register load/store
227		 * instructions, so MSA context has to be copied to kernel
228		 * memory and later loaded to registers. The same is true of
229		 * scalar FP context, so FPU & MSA should have already been
230		 * disabled whilst handling scalar FP context.
231		 */
232		BUG_ON(IS_ENABLED(CONFIG_EVA));
233
234		write_msa_csr(csr);
235		err |= _restore_msa_all_upper(&msa->wr);
236		preempt_enable();
237	} else {
238		preempt_enable();
239
240		current->thread.fpu.msacsr = csr;
241
242		for (i = 0; i < NUM_FPU_REGS; i++) {
243			err |= __get_user(val, &msa->wr[i]);
244			set_fpr64(&current->thread.fpu.fpr[i], 1, val);
245		}
246	}
247
248	return err;
249}
250
251#else /* !CONFIG_CPU_HAS_MSA */
252
253static int save_msa_extcontext(void __user *buf)
254{
255	return 0;
256}
257
258static int restore_msa_extcontext(void __user *buf, unsigned int size)
259{
260	return SIGSYS;
261}
262
263#endif /* !CONFIG_CPU_HAS_MSA */
264
265static int save_extcontext(void __user *buf)
266{
267	int sz;
268
269	sz = save_msa_extcontext(buf);
270	if (sz < 0)
271		return sz;
272	buf += sz;
273
274	/* If no context was saved then trivially return */
275	if (!sz)
276		return 0;
277
278	/* Write the end marker */
279	if (__put_user(END_EXTCONTEXT_MAGIC, (u32 *)buf))
280		return -EFAULT;
281
282	sz += sizeof(((struct extcontext *)NULL)->magic);
283	return sz;
284}
285
286static int restore_extcontext(void __user *buf)
287{
288	struct extcontext ext;
289	int err;
290
291	while (1) {
292		err = __get_user(ext.magic, (unsigned int *)buf);
293		if (err)
294			return err;
295
296		if (ext.magic == END_EXTCONTEXT_MAGIC)
297			return 0;
298
299		err = __get_user(ext.size, (unsigned int *)(buf
300			+ offsetof(struct extcontext, size)));
301		if (err)
302			return err;
303
304		switch (ext.magic) {
305		case MSA_EXTCONTEXT_MAGIC:
306			err = restore_msa_extcontext(buf, ext.size);
307			break;
308
309		default:
310			err = -EINVAL;
311			break;
312		}
313
314		if (err)
315			return err;
316
317		buf += ext.size;
318	}
319}
320
321/*
322 * Helper routines
323 */
324int protected_save_fp_context(void __user *sc)
325{
326	struct mips_abi *abi = current->thread.abi;
327	uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
328	uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
329	uint32_t __user *used_math = sc + abi->off_sc_used_math;
330	unsigned int used, ext_sz;
331	int err;
332
333	used = used_math() ? USED_FP : 0;
334	if (!used)
335		goto fp_done;
336
337	if (!test_thread_flag(TIF_32BIT_FPREGS))
338		used |= USED_FR1;
339	if (test_thread_flag(TIF_HYBRID_FPREGS))
340		used |= USED_HYBRID_FPRS;
341
342	/*
343	 * EVA does not have userland equivalents of ldc1 or sdc1, so
344	 * save to the kernel FP context & copy that to userland below.
345	 */
346	if (IS_ENABLED(CONFIG_EVA))
347		lose_fpu(1);
348
349	while (1) {
350		lock_fpu_owner();
351		if (is_fpu_owner()) {
352			err = save_fp_context(sc);
353			unlock_fpu_owner();
354		} else {
355			unlock_fpu_owner();
356			err = copy_fp_to_sigcontext(sc);
357		}
358		if (likely(!err))
359			break;
360		/* touch the sigcontext and try again */
361		err = __put_user(0, &fpregs[0]) |
362			__put_user(0, &fpregs[31]) |
363			__put_user(0, csr);
364		if (err)
365			return err;	/* really bad sigcontext */
366	}
367
368fp_done:
369	ext_sz = err = save_extcontext(sc_to_extcontext(sc));
370	if (err < 0)
371		return err;
372	used |= ext_sz ? USED_EXTCONTEXT : 0;
373
374	return __put_user(used, used_math);
375}
376
377int protected_restore_fp_context(void __user *sc)
378{
379	struct mips_abi *abi = current->thread.abi;
380	uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
381	uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
382	uint32_t __user *used_math = sc + abi->off_sc_used_math;
383	unsigned int used;
384	int err, sig = 0, tmp __maybe_unused;
385
386	err = __get_user(used, used_math);
387	conditional_used_math(used & USED_FP);
388
389	/*
390	 * The signal handler may have used FPU; give it up if the program
391	 * doesn't want it following sigreturn.
392	 */
393	if (err || !(used & USED_FP))
394		lose_fpu(0);
395	if (err)
396		return err;
397	if (!(used & USED_FP))
398		goto fp_done;
399
400	err = sig = fpcsr_pending(csr);
401	if (err < 0)
402		return err;
403
404	/*
405	 * EVA does not have userland equivalents of ldc1 or sdc1, so we
406	 * disable the FPU here such that the code below simply copies to
407	 * the kernel FP context.
408	 */
409	if (IS_ENABLED(CONFIG_EVA))
410		lose_fpu(0);
411
412	while (1) {
413		lock_fpu_owner();
414		if (is_fpu_owner()) {
415			err = restore_fp_context(sc);
416			unlock_fpu_owner();
417		} else {
418			unlock_fpu_owner();
419			err = copy_fp_from_sigcontext(sc);
420		}
421		if (likely(!err))
422			break;
423		/* touch the sigcontext and try again */
424		err = __get_user(tmp, &fpregs[0]) |
425			__get_user(tmp, &fpregs[31]) |
426			__get_user(tmp, csr);
427		if (err)
428			break;	/* really bad sigcontext */
429	}
430
431fp_done:
432	if (!err && (used & USED_EXTCONTEXT))
433		err = restore_extcontext(sc_to_extcontext(sc));
434
435	return err ?: sig;
436}
437
438int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
439{
440	int err = 0;
441	int i;
 
442
443	err |= __put_user(regs->cp0_epc, &sc->sc_pc);
444
445	err |= __put_user(0, &sc->sc_regs[0]);
446	for (i = 1; i < 32; i++)
447		err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
448
449#ifdef CONFIG_CPU_HAS_SMARTMIPS
450	err |= __put_user(regs->acx, &sc->sc_acx);
451#endif
452	err |= __put_user(regs->hi, &sc->sc_mdhi);
453	err |= __put_user(regs->lo, &sc->sc_mdlo);
454	if (cpu_has_dsp) {
455		err |= __put_user(mfhi1(), &sc->sc_hi1);
456		err |= __put_user(mflo1(), &sc->sc_lo1);
457		err |= __put_user(mfhi2(), &sc->sc_hi2);
458		err |= __put_user(mflo2(), &sc->sc_lo2);
459		err |= __put_user(mfhi3(), &sc->sc_hi3);
460		err |= __put_user(mflo3(), &sc->sc_lo3);
461		err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
462	}
463
 
 
464
465	/*
466	 * Save FPU state to signal context. Signal handler
467	 * will "inherit" current FPU state.
468	 */
469	err |= protected_save_fp_context(sc);
470
 
471	return err;
472}
473
474static size_t extcontext_max_size(void)
475{
476	size_t sz = 0;
477
478	/*
479	 * The assumption here is that between this point & the point at which
480	 * the extended context is saved the size of the context should only
481	 * ever be able to shrink (if the task is preempted), but never grow.
482	 * That is, what this function returns is an upper bound on the size of
483	 * the extended context for the current task at the current time.
484	 */
485
486	if (thread_msa_context_live())
487		sz += sizeof(struct msa_extcontext);
488
489	/* If any context is saved then we'll append the end marker */
490	if (sz)
491		sz += sizeof(((struct extcontext *)NULL)->magic);
492
493	return sz;
494}
495
496int fpcsr_pending(unsigned int __user *fpcsr)
497{
498	int err, sig = 0;
499	unsigned int csr, enabled;
500
501	err = __get_user(csr, fpcsr);
502	enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
503	/*
504	 * If the signal handler set some FPU exceptions, clear it and
505	 * send SIGFPE.
506	 */
507	if (csr & enabled) {
508		csr &= ~enabled;
509		err |= __put_user(csr, fpcsr);
510		sig = SIGFPE;
511	}
512	return err ?: sig;
513}
514
 
 
 
 
 
 
 
 
 
 
 
 
515int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
516{
 
517	unsigned long treg;
518	int err = 0;
519	int i;
520
521	/* Always make any pending restarted system calls return -EINTR */
522	current->restart_block.fn = do_no_restart_syscall;
523
524	err |= __get_user(regs->cp0_epc, &sc->sc_pc);
525
526#ifdef CONFIG_CPU_HAS_SMARTMIPS
527	err |= __get_user(regs->acx, &sc->sc_acx);
528#endif
529	err |= __get_user(regs->hi, &sc->sc_mdhi);
530	err |= __get_user(regs->lo, &sc->sc_mdlo);
531	if (cpu_has_dsp) {
532		err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
533		err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
534		err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
535		err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
536		err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
537		err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
538		err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
539	}
540
541	for (i = 1; i < 32; i++)
542		err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
543
544	return err ?: protected_restore_fp_context(sc);
545}
546
547#ifdef CONFIG_WAR_ICACHE_REFILLS
548#define SIGMASK		~(cpu_icache_line_size()-1)
549#else
550#define SIGMASK		ALMASK
551#endif
 
 
 
 
 
 
552
553void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
554			  size_t frame_size)
555{
556	unsigned long sp;
557
558	/* Leave space for potential extended context */
559	frame_size += extcontext_max_size();
560
561	/* Default to using normal stack */
562	sp = regs->regs[29];
563
564	/*
565	 * If we are on the alternate signal stack and would overflow it, don't.
566	 * Return an always-bogus address instead so we will die with SIGSEGV.
567	 */
568	if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
569		return (void __user __force *)(-1UL);
570
571	/*
572	 * FPU emulator may have it's own trampoline active just
573	 * above the user stack, 16-bytes before the next lowest
574	 * 16 byte boundary.  Try to avoid trashing it.
575	 */
576	sp -= 32;
577
578	sp = sigsp(sp, ksig);
 
 
579
580	return (void __user *)((sp - frame_size) & SIGMASK);
581}
582
583/*
584 * Atomically swap in the new signal mask, and wait for a signal.
585 */
586
587#ifdef CONFIG_TRAD_SIGNALS
588SYSCALL_DEFINE1(sigsuspend, sigset_t __user *, uset)
589{
590	return sys_rt_sigsuspend(uset, sizeof(sigset_t));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
591}
592#endif
593
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
594#ifdef CONFIG_TRAD_SIGNALS
595SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
596	struct sigaction __user *, oact)
597{
598	struct k_sigaction new_ka, old_ka;
599	int ret;
600	int err = 0;
601
602	if (act) {
603		old_sigset_t mask;
604
605		if (!access_ok(act, sizeof(*act)))
606			return -EFAULT;
607		err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
608		err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
609		err |= __get_user(mask, &act->sa_mask.sig[0]);
610		if (err)
611			return -EFAULT;
612
613		siginitset(&new_ka.sa.sa_mask, mask);
614	}
615
616	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
617
618	if (!ret && oact) {
619		if (!access_ok(oact, sizeof(*oact)))
620			return -EFAULT;
621		err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
622		err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
623		err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
624		err |= __put_user(0, &oact->sa_mask.sig[1]);
625		err |= __put_user(0, &oact->sa_mask.sig[2]);
626		err |= __put_user(0, &oact->sa_mask.sig[3]);
627		if (err)
628			return -EFAULT;
629	}
630
631	return ret;
632}
633#endif
634
 
 
 
 
 
 
 
 
 
635#ifdef CONFIG_TRAD_SIGNALS
636asmlinkage void sys_sigreturn(void)
637{
638	struct sigframe __user *frame;
639	struct pt_regs *regs;
640	sigset_t blocked;
641	int sig;
642
643	regs = current_pt_regs();
644	frame = (struct sigframe __user *)regs->regs[29];
645	if (!access_ok(frame, sizeof(*frame)))
646		goto badframe;
647	if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
648		goto badframe;
649
650	set_current_blocked(&blocked);
 
 
 
 
651
652	sig = restore_sigcontext(regs, &frame->sf_sc);
653	if (sig < 0)
654		goto badframe;
655	else if (sig)
656		force_sig(sig);
657
658	/*
659	 * Don't let your children do this ...
660	 */
661	__asm__ __volatile__(
662		"move\t$29, %0\n\t"
663		"j\tsyscall_exit"
664		: /* no outputs */
665		: "r" (regs));
666	/* Unreached */
667
668badframe:
669	force_sig(SIGSEGV);
670}
671#endif /* CONFIG_TRAD_SIGNALS */
672
673asmlinkage void sys_rt_sigreturn(void)
674{
675	struct rt_sigframe __user *frame;
676	struct pt_regs *regs;
677	sigset_t set;
678	int sig;
679
680	regs = current_pt_regs();
681	frame = (struct rt_sigframe __user *)regs->regs[29];
682	if (!access_ok(frame, sizeof(*frame)))
683		goto badframe;
684	if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
685		goto badframe;
686
687	set_current_blocked(&set);
 
 
 
 
688
689	sig = restore_sigcontext(regs, &frame->rs_uc.uc_mcontext);
690	if (sig < 0)
691		goto badframe;
692	else if (sig)
693		force_sig(sig);
694
695	if (restore_altstack(&frame->rs_uc.uc_stack))
696		goto badframe;
 
697
698	/*
699	 * Don't let your children do this ...
700	 */
701	__asm__ __volatile__(
702		"move\t$29, %0\n\t"
703		"j\tsyscall_exit"
704		: /* no outputs */
705		: "r" (regs));
706	/* Unreached */
707
708badframe:
709	force_sig(SIGSEGV);
710}
711
712#ifdef CONFIG_TRAD_SIGNALS
713static int setup_frame(void *sig_return, struct ksignal *ksig,
714		       struct pt_regs *regs, sigset_t *set)
715{
716	struct sigframe __user *frame;
717	int err = 0;
718
719	frame = get_sigframe(ksig, regs, sizeof(*frame));
720	if (!access_ok(frame, sizeof (*frame)))
721		return -EFAULT;
722
723	err |= setup_sigcontext(regs, &frame->sf_sc);
724	err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
725	if (err)
726		return -EFAULT;
727
728	/*
729	 * Arguments to signal handler:
730	 *
731	 *   a0 = signal number
732	 *   a1 = 0 (should be cause)
733	 *   a2 = pointer to struct sigcontext
734	 *
735	 * $25 and c0_epc point to the signal handler, $29 points to the
736	 * struct sigframe.
737	 */
738	regs->regs[ 4] = ksig->sig;
739	regs->regs[ 5] = 0;
740	regs->regs[ 6] = (unsigned long) &frame->sf_sc;
741	regs->regs[29] = (unsigned long) frame;
742	regs->regs[31] = (unsigned long) sig_return;
743	regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
744
745	DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
746	       current->comm, current->pid,
747	       frame, regs->cp0_epc, regs->regs[31]);
748	return 0;
 
 
 
 
749}
750#endif
751
752static int setup_rt_frame(void *sig_return, struct ksignal *ksig,
753			  struct pt_regs *regs, sigset_t *set)
 
754{
755	struct rt_sigframe __user *frame;
 
756
757	frame = get_sigframe(ksig, regs, sizeof(*frame));
758	if (!access_ok(frame, sizeof (*frame)))
759		return -EFAULT;
760
761	/* Create siginfo.  */
762	if (copy_siginfo_to_user(&frame->rs_info, &ksig->info))
763		return -EFAULT;
764
765	/* Create the ucontext.	 */
766	if (__put_user(0, &frame->rs_uc.uc_flags))
767		return -EFAULT;
768	if (__put_user(NULL, &frame->rs_uc.uc_link))
769		return -EFAULT;
770	if (__save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]))
771		return -EFAULT;
772	if (setup_sigcontext(regs, &frame->rs_uc.uc_mcontext))
773		return -EFAULT;
774	if (__copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set)))
775		return -EFAULT;
 
 
 
776
777	/*
778	 * Arguments to signal handler:
779	 *
780	 *   a0 = signal number
781	 *   a1 = 0 (should be cause)
782	 *   a2 = pointer to ucontext
783	 *
784	 * $25 and c0_epc point to the signal handler, $29 points to
785	 * the struct rt_sigframe.
786	 */
787	regs->regs[ 4] = ksig->sig;
788	regs->regs[ 5] = (unsigned long) &frame->rs_info;
789	regs->regs[ 6] = (unsigned long) &frame->rs_uc;
790	regs->regs[29] = (unsigned long) frame;
791	regs->regs[31] = (unsigned long) sig_return;
792	regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
793
794	DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
795	       current->comm, current->pid,
796	       frame, regs->cp0_epc, regs->regs[31]);
797
798	return 0;
 
 
 
 
799}
800
801struct mips_abi mips_abi = {
802#ifdef CONFIG_TRAD_SIGNALS
803	.setup_frame	= setup_frame,
 
804#endif
805	.setup_rt_frame = setup_rt_frame,
806	.restart	= __NR_restart_syscall,
807
808	.off_sc_fpregs = offsetof(struct sigcontext, sc_fpregs),
809	.off_sc_fpc_csr = offsetof(struct sigcontext, sc_fpc_csr),
810	.off_sc_used_math = offsetof(struct sigcontext, sc_used_math),
811
812	.vdso		= &vdso_image,
813};
814
815static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 
816{
817	sigset_t *oldset = sigmask_to_save();
818	int ret;
819	struct mips_abi *abi = current->thread.abi;
820	void *vdso = current->mm->context.vdso;
821
822	/*
823	 * If we were emulating a delay slot instruction, exit that frame such
824	 * that addresses in the sigframe are as expected for userland and we
825	 * don't have a problem if we reuse the thread's frame for an
826	 * instruction within the signal handler.
827	 */
828	dsemul_thread_rollback(regs);
829
830	if (regs->regs[0]) {
831		switch(regs->regs[2]) {
832		case ERESTART_RESTARTBLOCK:
833		case ERESTARTNOHAND:
834			regs->regs[2] = EINTR;
835			break;
836		case ERESTARTSYS:
837			if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
838				regs->regs[2] = EINTR;
839				break;
840			}
841			fallthrough;
842		case ERESTARTNOINTR:
843			regs->regs[7] = regs->regs[26];
844			regs->regs[2] = regs->regs[0];
845			regs->cp0_epc -= 4;
846		}
847
848		regs->regs[0] = 0;		/* Don't deal with this again.	*/
849	}
850
851	rseq_signal_deliver(ksig, regs);
852
853	if (sig_uses_siginfo(&ksig->ka, abi))
854		ret = abi->setup_rt_frame(vdso + abi->vdso->off_rt_sigreturn,
855					  ksig, regs, oldset);
856	else
857		ret = abi->setup_frame(vdso + abi->vdso->off_sigreturn,
858				       ksig, regs, oldset);
859
860	signal_setup_done(ret, ksig, 0);
 
 
 
 
 
 
 
 
 
 
861}
862
863static void do_signal(struct pt_regs *regs)
864{
865	struct ksignal ksig;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
866
867	if (get_signal(&ksig)) {
868		/* Whee!  Actually deliver the signal.	*/
869		handle_signal(&ksig, regs);
870		return;
871	}
872
873	if (regs->regs[0]) {
874		switch (regs->regs[2]) {
875		case ERESTARTNOHAND:
876		case ERESTARTSYS:
877		case ERESTARTNOINTR:
878			regs->regs[2] = regs->regs[0];
879			regs->regs[7] = regs->regs[26];
880			regs->cp0_epc -= 4;
881			break;
882
883		case ERESTART_RESTARTBLOCK:
884			regs->regs[2] = current->thread.abi->restart;
885			regs->regs[7] = regs->regs[26];
886			regs->cp0_epc -= 4;
887			break;
888		}
889		regs->regs[0] = 0;	/* Don't deal with this again.	*/
890	}
891
892	/*
893	 * If there's no signal to deliver, we just put the saved sigmask
894	 * back
895	 */
896	restore_saved_sigmask();
 
 
 
897}
898
899/*
900 * notification of userspace execution resumption
901 * - triggered by the TIF_WORK_MASK flags
902 */
903asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
904	__u32 thread_info_flags)
905{
906	local_irq_enable();
907
908	user_exit();
909
910	if (thread_info_flags & _TIF_UPROBE)
911		uprobe_notify_resume(regs);
912
913	/* deal with pending signal delivery */
914	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
915		do_signal(regs);
916
917	if (thread_info_flags & _TIF_NOTIFY_RESUME)
918		resume_user_mode_work(regs);
919
920	user_enter();
 
 
921}
922
923#if defined(CONFIG_SMP) && defined(CONFIG_MIPS_FP_SUPPORT)
924static int smp_save_fp_context(void __user *sc)
925{
926	return raw_cpu_has_fpu
927	       ? save_hw_fp_context(sc)
928	       : copy_fp_to_sigcontext(sc);
929}
930
931static int smp_restore_fp_context(void __user *sc)
932{
933	return raw_cpu_has_fpu
934	       ? restore_hw_fp_context(sc)
935	       : copy_fp_from_sigcontext(sc);
936}
937#endif
938
939static int signal_setup(void)
940{
941	/*
942	 * The offset from sigcontext to extended context should be the same
943	 * regardless of the type of signal, such that userland can always know
944	 * where to look if it wishes to find the extended context structures.
945	 */
946	BUILD_BUG_ON((offsetof(struct sigframe, sf_extcontext) -
947		      offsetof(struct sigframe, sf_sc)) !=
948		     (offsetof(struct rt_sigframe, rs_uc.uc_extcontext) -
949		      offsetof(struct rt_sigframe, rs_uc.uc_mcontext)));
950
951#if defined(CONFIG_SMP) && defined(CONFIG_MIPS_FP_SUPPORT)
952	/* For now just do the cpu_has_fpu check when the functions are invoked */
953	save_fp_context = smp_save_fp_context;
954	restore_fp_context = smp_restore_fp_context;
955#else
956	if (cpu_has_fpu) {
957		save_fp_context = save_hw_fp_context;
958		restore_fp_context = restore_hw_fp_context;
959	} else {
960		save_fp_context = copy_fp_to_sigcontext;
961		restore_fp_context = copy_fp_from_sigcontext;
962	}
963#endif /* CONFIG_SMP */
964
965	return 0;
966}
967
968arch_initcall(signal_setup);