xref: /openbmc/linux/arch/powerpc/kernel/signal_32.c (revision dcabb06bf127b3e0d3fbc94a2b65dd56c2725851)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Signal handling for 32bit PPC and 32bit tasks on 64bit PPC
4  *
5  *  PowerPC version
6  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
7  * Copyright (C) 2001 IBM
8  * Copyright (C) 1997,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
9  * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
10  *
11  *  Derived from "arch/i386/kernel/signal.c"
12  *    Copyright (C) 1991, 1992 Linus Torvalds
13  *    1997-11-28  Modified for POSIX.1b signals by Richard Henderson
14  */
15 
16 #include <linux/sched.h>
17 #include <linux/mm.h>
18 #include <linux/smp.h>
19 #include <linux/kernel.h>
20 #include <linux/signal.h>
21 #include <linux/errno.h>
22 #include <linux/elf.h>
23 #include <linux/ptrace.h>
24 #include <linux/pagemap.h>
25 #include <linux/ratelimit.h>
26 #include <linux/syscalls.h>
27 #ifdef CONFIG_PPC64
28 #include <linux/compat.h>
29 #else
30 #include <linux/wait.h>
31 #include <linux/unistd.h>
32 #include <linux/stddef.h>
33 #include <linux/tty.h>
34 #include <linux/binfmts.h>
35 #endif
36 
37 #include <linux/uaccess.h>
38 #include <asm/cacheflush.h>
39 #include <asm/syscalls.h>
40 #include <asm/sigcontext.h>
41 #include <asm/vdso.h>
42 #include <asm/switch_to.h>
43 #include <asm/tm.h>
44 #include <asm/asm-prototypes.h>
45 #ifdef CONFIG_PPC64
46 #include "ppc32.h"
47 #include <asm/unistd.h>
48 #else
49 #include <asm/ucontext.h>
50 #endif
51 
52 #include "signal.h"
53 
54 
55 #ifdef CONFIG_PPC64
56 #define old_sigaction	old_sigaction32
57 #define sigcontext	sigcontext32
58 #define mcontext	mcontext32
59 #define ucontext	ucontext32
60 
61 /*
62  * Userspace code may pass a ucontext which doesn't include VSX added
63  * at the end.  We need to check for this case.
64  */
65 #define UCONTEXTSIZEWITHOUTVSX \
66 		(sizeof(struct ucontext) - sizeof(elf_vsrreghalf_t32))
67 
68 /*
69  * Returning 0 means we return to userspace via
70  * ret_from_except and thus restore all user
71  * registers from *regs.  This is what we need
72  * to do when a signal has been delivered.
73  */
74 
75 #define GP_REGS_SIZE	min(sizeof(elf_gregset_t32), sizeof(struct pt_regs32))
76 #undef __SIGNAL_FRAMESIZE
77 #define __SIGNAL_FRAMESIZE	__SIGNAL_FRAMESIZE32
78 #undef ELF_NVRREG
79 #define ELF_NVRREG	ELF_NVRREG32
80 
81 /*
82  * Functions for flipping sigsets (thanks to brain dead generic
83  * implementation that makes things simple for little endian only)
84  */
85 #define unsafe_put_sigset_t	unsafe_put_compat_sigset
86 
87 static inline int get_sigset_t(sigset_t *set,
88 			       const compat_sigset_t __user *uset)
89 {
90 	return get_compat_sigset(set, uset);
91 }
92 
93 #define to_user_ptr(p)		ptr_to_compat(p)
94 #define from_user_ptr(p)	compat_ptr(p)
95 
96 static __always_inline int
97 save_general_regs_unsafe(struct pt_regs *regs, struct mcontext __user *frame)
98 {
99 	elf_greg_t64 *gregs = (elf_greg_t64 *)regs;
100 	int val, i;
101 
102 	WARN_ON(!FULL_REGS(regs));
103 
104 	for (i = 0; i <= PT_RESULT; i ++) {
105 		/* Force usr to alway see softe as 1 (interrupts enabled) */
106 		if (i == PT_SOFTE)
107 			val = 1;
108 		else
109 			val = gregs[i];
110 
111 		unsafe_put_user(val, &frame->mc_gregs[i], failed);
112 	}
113 	return 0;
114 
115 failed:
116 	return 1;
117 }
118 
119 static inline int restore_general_regs(struct pt_regs *regs,
120 		struct mcontext __user *sr)
121 {
122 	elf_greg_t64 *gregs = (elf_greg_t64 *)regs;
123 	int i;
124 
125 	for (i = 0; i <= PT_RESULT; i++) {
126 		if ((i == PT_MSR) || (i == PT_SOFTE))
127 			continue;
128 		if (__get_user(gregs[i], &sr->mc_gregs[i]))
129 			return -EFAULT;
130 	}
131 	return 0;
132 }
133 
134 #else /* CONFIG_PPC64 */
135 
136 #define GP_REGS_SIZE	min(sizeof(elf_gregset_t), sizeof(struct pt_regs))
137 
138 #define unsafe_put_sigset_t(uset, set, label) do {			\
139 	sigset_t __user *__us = uset	;				\
140 	const sigset_t *__s = set;					\
141 									\
142 	unsafe_copy_to_user(__us, __s, sizeof(*__us), label);		\
143 } while (0)
144 
145 static inline int get_sigset_t(sigset_t *set, const sigset_t __user *uset)
146 {
147 	return copy_from_user(set, uset, sizeof(*uset));
148 }
149 
150 #define to_user_ptr(p)		((unsigned long)(p))
151 #define from_user_ptr(p)	((void __user *)(p))
152 
153 static __always_inline int
154 save_general_regs_unsafe(struct pt_regs *regs, struct mcontext __user *frame)
155 {
156 	WARN_ON(!FULL_REGS(regs));
157 	unsafe_copy_to_user(&frame->mc_gregs, regs, GP_REGS_SIZE, failed);
158 	return 0;
159 
160 failed:
161 	return 1;
162 }
163 
164 static inline int restore_general_regs(struct pt_regs *regs,
165 		struct mcontext __user *sr)
166 {
167 	/* copy up to but not including MSR */
168 	if (__copy_from_user(regs, &sr->mc_gregs,
169 				PT_MSR * sizeof(elf_greg_t)))
170 		return -EFAULT;
171 	/* copy from orig_r3 (the word after the MSR) up to the end */
172 	if (__copy_from_user(&regs->orig_gpr3, &sr->mc_gregs[PT_ORIG_R3],
173 				GP_REGS_SIZE - PT_ORIG_R3 * sizeof(elf_greg_t)))
174 		return -EFAULT;
175 	return 0;
176 }
177 #endif
178 
179 #define unsafe_save_general_regs(regs, frame, label) do {	\
180 	if (save_general_regs_unsafe(regs, frame))	\
181 		goto label;					\
182 } while (0)
183 
184 /*
185  * When we have signals to deliver, we set up on the
186  * user stack, going down from the original stack pointer:
187  *	an ABI gap of 56 words
188  *	an mcontext struct
189  *	a sigcontext struct
190  *	a gap of __SIGNAL_FRAMESIZE bytes
191  *
192  * Each of these things must be a multiple of 16 bytes in size. The following
193  * structure represent all of this except the __SIGNAL_FRAMESIZE gap
194  *
195  */
196 struct sigframe {
197 	struct sigcontext sctx;		/* the sigcontext */
198 	struct mcontext	mctx;		/* all the register values */
199 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
200 	struct sigcontext sctx_transact;
201 	struct mcontext	mctx_transact;
202 #endif
203 	/*
204 	 * Programs using the rs6000/xcoff abi can save up to 19 gp
205 	 * regs and 18 fp regs below sp before decrementing it.
206 	 */
207 	int			abigap[56];
208 };
209 
210 /*
211  *  When we have rt signals to deliver, we set up on the
212  *  user stack, going down from the original stack pointer:
213  *	one rt_sigframe struct (siginfo + ucontext + ABI gap)
214  *	a gap of __SIGNAL_FRAMESIZE+16 bytes
215  *  (the +16 is to get the siginfo and ucontext in the same
216  *  positions as in older kernels).
217  *
218  *  Each of these things must be a multiple of 16 bytes in size.
219  *
220  */
221 struct rt_sigframe {
222 #ifdef CONFIG_PPC64
223 	compat_siginfo_t info;
224 #else
225 	struct siginfo info;
226 #endif
227 	struct ucontext	uc;
228 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
229 	struct ucontext	uc_transact;
230 #endif
231 	/*
232 	 * Programs using the rs6000/xcoff abi can save up to 19 gp
233 	 * regs and 18 fp regs below sp before decrementing it.
234 	 */
235 	int			abigap[56];
236 };
237 
238 /*
239  * Save the current user registers on the user stack.
240  * We only save the altivec/spe registers if the process has used
241  * altivec/spe instructions at some point.
242  */
243 static void prepare_save_user_regs(int ctx_has_vsx_region)
244 {
245 	/* Make sure floating point registers are stored in regs */
246 	flush_fp_to_thread(current);
247 #ifdef CONFIG_ALTIVEC
248 	if (current->thread.used_vr)
249 		flush_altivec_to_thread(current);
250 	if (cpu_has_feature(CPU_FTR_ALTIVEC))
251 		current->thread.vrsave = mfspr(SPRN_VRSAVE);
252 #endif
253 #ifdef CONFIG_VSX
254 	if (current->thread.used_vsr && ctx_has_vsx_region)
255 		flush_vsx_to_thread(current);
256 #endif
257 #ifdef CONFIG_SPE
258 	if (current->thread.used_spe)
259 		flush_spe_to_thread(current);
260 #endif
261 }
262 
263 static int save_user_regs_unsafe(struct pt_regs *regs, struct mcontext __user *frame,
264 				 struct mcontext __user *tm_frame, int ctx_has_vsx_region)
265 {
266 	unsigned long msr = regs->msr;
267 
268 	/* save general registers */
269 	unsafe_save_general_regs(regs, frame, failed);
270 
271 #ifdef CONFIG_ALTIVEC
272 	/* save altivec registers */
273 	if (current->thread.used_vr) {
274 		unsafe_copy_to_user(&frame->mc_vregs, &current->thread.vr_state,
275 				    ELF_NVRREG * sizeof(vector128), failed);
276 		/* set MSR_VEC in the saved MSR value to indicate that
277 		   frame->mc_vregs contains valid data */
278 		msr |= MSR_VEC;
279 	}
280 	/* else assert((regs->msr & MSR_VEC) == 0) */
281 
282 	/* We always copy to/from vrsave, it's 0 if we don't have or don't
283 	 * use altivec. Since VSCR only contains 32 bits saved in the least
284 	 * significant bits of a vector, we "cheat" and stuff VRSAVE in the
285 	 * most significant bits of that same vector. --BenH
286 	 * Note that the current VRSAVE value is in the SPR at this point.
287 	 */
288 	unsafe_put_user(current->thread.vrsave, (u32 __user *)&frame->mc_vregs[32],
289 			failed);
290 #endif /* CONFIG_ALTIVEC */
291 	unsafe_copy_fpr_to_user(&frame->mc_fregs, current, failed);
292 
293 	/*
294 	 * Clear the MSR VSX bit to indicate there is no valid state attached
295 	 * to this context, except in the specific case below where we set it.
296 	 */
297 	msr &= ~MSR_VSX;
298 #ifdef CONFIG_VSX
299 	/*
300 	 * Copy VSR 0-31 upper half from thread_struct to local
301 	 * buffer, then write that to userspace.  Also set MSR_VSX in
302 	 * the saved MSR value to indicate that frame->mc_vregs
303 	 * contains valid data
304 	 */
305 	if (current->thread.used_vsr && ctx_has_vsx_region) {
306 		unsafe_copy_vsx_to_user(&frame->mc_vsregs, current, failed);
307 		msr |= MSR_VSX;
308 	}
309 #endif /* CONFIG_VSX */
310 #ifdef CONFIG_SPE
311 	/* save spe registers */
312 	if (current->thread.used_spe) {
313 		unsafe_copy_to_user(&frame->mc_vregs, current->thread.evr,
314 				    ELF_NEVRREG * sizeof(u32), failed);
315 		/* set MSR_SPE in the saved MSR value to indicate that
316 		   frame->mc_vregs contains valid data */
317 		msr |= MSR_SPE;
318 	}
319 	/* else assert((regs->msr & MSR_SPE) == 0) */
320 
321 	/* We always copy to/from spefscr */
322 	unsafe_put_user(current->thread.spefscr,
323 			(u32 __user *)&frame->mc_vregs + ELF_NEVRREG, failed);
324 #endif /* CONFIG_SPE */
325 
326 	unsafe_put_user(msr, &frame->mc_gregs[PT_MSR], failed);
327 
328 	/* We need to write 0 the MSR top 32 bits in the tm frame so that we
329 	 * can check it on the restore to see if TM is active
330 	 */
331 	if (tm_frame)
332 		unsafe_put_user(0, &tm_frame->mc_gregs[PT_MSR], failed);
333 
334 	return 0;
335 
336 failed:
337 	return 1;
338 }
339 
340 #define unsafe_save_user_regs(regs, frame, tm_frame, has_vsx, label) do { \
341 	if (save_user_regs_unsafe(regs, frame, tm_frame, has_vsx))	\
342 		goto label;						\
343 } while (0)
344 
345 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
346 /*
347  * Save the current user registers on the user stack.
348  * We only save the altivec/spe registers if the process has used
349  * altivec/spe instructions at some point.
350  * We also save the transactional registers to a second ucontext in the
351  * frame.
352  *
353  * See save_user_regs_unsafe() and signal_64.c:setup_tm_sigcontexts().
354  */
355 static void prepare_save_tm_user_regs(void)
356 {
357 	WARN_ON(tm_suspend_disabled);
358 
359 #ifdef CONFIG_ALTIVEC
360 	if (cpu_has_feature(CPU_FTR_ALTIVEC))
361 		current->thread.ckvrsave = mfspr(SPRN_VRSAVE);
362 #endif
363 #ifdef CONFIG_SPE
364 	if (current->thread.used_spe)
365 		flush_spe_to_thread(current);
366 #endif
367 }
368 
369 static int save_tm_user_regs_unsafe(struct pt_regs *regs, struct mcontext __user *frame,
370 				    struct mcontext __user *tm_frame, unsigned long msr)
371 {
372 	/* Save both sets of general registers */
373 	unsafe_save_general_regs(&current->thread.ckpt_regs, frame, failed);
374 	unsafe_save_general_regs(regs, tm_frame, failed);
375 
376 	/* Stash the top half of the 64bit MSR into the 32bit MSR word
377 	 * of the transactional mcontext.  This way we have a backward-compatible
378 	 * MSR in the 'normal' (checkpointed) mcontext and additionally one can
379 	 * also look at what type of transaction (T or S) was active at the
380 	 * time of the signal.
381 	 */
382 	unsafe_put_user((msr >> 32), &tm_frame->mc_gregs[PT_MSR], failed);
383 
384 #ifdef CONFIG_ALTIVEC
385 	/* save altivec registers */
386 	if (current->thread.used_vr) {
387 		unsafe_copy_to_user(&frame->mc_vregs, &current->thread.ckvr_state,
388 				    ELF_NVRREG * sizeof(vector128), failed);
389 		if (msr & MSR_VEC)
390 			unsafe_copy_to_user(&tm_frame->mc_vregs,
391 					    &current->thread.vr_state,
392 					    ELF_NVRREG * sizeof(vector128), failed);
393 		else
394 			unsafe_copy_to_user(&tm_frame->mc_vregs,
395 					    &current->thread.ckvr_state,
396 					    ELF_NVRREG * sizeof(vector128), failed);
397 
398 		/* set MSR_VEC in the saved MSR value to indicate that
399 		 * frame->mc_vregs contains valid data
400 		 */
401 		msr |= MSR_VEC;
402 	}
403 
404 	/* We always copy to/from vrsave, it's 0 if we don't have or don't
405 	 * use altivec. Since VSCR only contains 32 bits saved in the least
406 	 * significant bits of a vector, we "cheat" and stuff VRSAVE in the
407 	 * most significant bits of that same vector. --BenH
408 	 */
409 	unsafe_put_user(current->thread.ckvrsave,
410 			(u32 __user *)&frame->mc_vregs[32], failed);
411 	if (msr & MSR_VEC)
412 		unsafe_put_user(current->thread.vrsave,
413 				(u32 __user *)&tm_frame->mc_vregs[32], failed);
414 	else
415 		unsafe_put_user(current->thread.ckvrsave,
416 				(u32 __user *)&tm_frame->mc_vregs[32], failed);
417 #endif /* CONFIG_ALTIVEC */
418 
419 	unsafe_copy_ckfpr_to_user(&frame->mc_fregs, current, failed);
420 	if (msr & MSR_FP)
421 		unsafe_copy_fpr_to_user(&tm_frame->mc_fregs, current, failed);
422 	else
423 		unsafe_copy_ckfpr_to_user(&tm_frame->mc_fregs, current, failed);
424 
425 #ifdef CONFIG_VSX
426 	/*
427 	 * Copy VSR 0-31 upper half from thread_struct to local
428 	 * buffer, then write that to userspace.  Also set MSR_VSX in
429 	 * the saved MSR value to indicate that frame->mc_vregs
430 	 * contains valid data
431 	 */
432 	if (current->thread.used_vsr) {
433 		unsafe_copy_ckvsx_to_user(&frame->mc_vsregs, current, failed);
434 		if (msr & MSR_VSX)
435 			unsafe_copy_vsx_to_user(&tm_frame->mc_vsregs, current, failed);
436 		else
437 			unsafe_copy_ckvsx_to_user(&tm_frame->mc_vsregs, current, failed);
438 
439 		msr |= MSR_VSX;
440 	}
441 #endif /* CONFIG_VSX */
442 #ifdef CONFIG_SPE
443 	/* SPE regs are not checkpointed with TM, so this section is
444 	 * simply the same as in save_user_regs_unsafe().
445 	 */
446 	if (current->thread.used_spe) {
447 		unsafe_copy_to_user(&frame->mc_vregs, current->thread.evr,
448 				    ELF_NEVRREG * sizeof(u32), failed);
449 		/* set MSR_SPE in the saved MSR value to indicate that
450 		 * frame->mc_vregs contains valid data */
451 		msr |= MSR_SPE;
452 	}
453 
454 	/* We always copy to/from spefscr */
455 	unsafe_put_user(current->thread.spefscr,
456 			(u32 __user *)&frame->mc_vregs + ELF_NEVRREG, failed);
457 #endif /* CONFIG_SPE */
458 
459 	unsafe_put_user(msr, &frame->mc_gregs[PT_MSR], failed);
460 
461 	return 0;
462 
463 failed:
464 	return 1;
465 }
466 #else
467 static void prepare_save_tm_user_regs(void) { }
468 
469 static int save_tm_user_regs_unsafe(struct pt_regs *regs, struct mcontext __user *frame,
470 				    struct mcontext __user *tm_frame, unsigned long msr)
471 {
472 	return 0;
473 }
474 #endif
475 
476 #define unsafe_save_tm_user_regs(regs, frame, tm_frame, msr, label) do { \
477 	if (save_tm_user_regs_unsafe(regs, frame, tm_frame, msr))	\
478 		goto label;						\
479 } while (0)
480 
481 /*
482  * Restore the current user register values from the user stack,
483  * (except for MSR).
484  */
485 static long restore_user_regs(struct pt_regs *regs,
486 			      struct mcontext __user *sr, int sig)
487 {
488 	long err;
489 	unsigned int save_r2 = 0;
490 	unsigned long msr;
491 #ifdef CONFIG_VSX
492 	int i;
493 #endif
494 
495 	/*
496 	 * restore general registers but not including MSR or SOFTE. Also
497 	 * take care of keeping r2 (TLS) intact if not a signal
498 	 */
499 	if (!sig)
500 		save_r2 = (unsigned int)regs->gpr[2];
501 	err = restore_general_regs(regs, sr);
502 	set_trap_norestart(regs);
503 	err |= __get_user(msr, &sr->mc_gregs[PT_MSR]);
504 	if (!sig)
505 		regs->gpr[2] = (unsigned long) save_r2;
506 	if (err)
507 		return 1;
508 
509 	/* if doing signal return, restore the previous little-endian mode */
510 	if (sig)
511 		regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
512 
513 #ifdef CONFIG_ALTIVEC
514 	/*
515 	 * Force the process to reload the altivec registers from
516 	 * current->thread when it next does altivec instructions
517 	 */
518 	regs->msr &= ~MSR_VEC;
519 	if (msr & MSR_VEC) {
520 		/* restore altivec registers from the stack */
521 		if (__copy_from_user(&current->thread.vr_state, &sr->mc_vregs,
522 				     sizeof(sr->mc_vregs)))
523 			return 1;
524 		current->thread.used_vr = true;
525 	} else if (current->thread.used_vr)
526 		memset(&current->thread.vr_state, 0,
527 		       ELF_NVRREG * sizeof(vector128));
528 
529 	/* Always get VRSAVE back */
530 	if (__get_user(current->thread.vrsave, (u32 __user *)&sr->mc_vregs[32]))
531 		return 1;
532 	if (cpu_has_feature(CPU_FTR_ALTIVEC))
533 		mtspr(SPRN_VRSAVE, current->thread.vrsave);
534 #endif /* CONFIG_ALTIVEC */
535 	if (copy_fpr_from_user(current, &sr->mc_fregs))
536 		return 1;
537 
538 #ifdef CONFIG_VSX
539 	/*
540 	 * Force the process to reload the VSX registers from
541 	 * current->thread when it next does VSX instruction.
542 	 */
543 	regs->msr &= ~MSR_VSX;
544 	if (msr & MSR_VSX) {
545 		/*
546 		 * Restore altivec registers from the stack to a local
547 		 * buffer, then write this out to the thread_struct
548 		 */
549 		if (copy_vsx_from_user(current, &sr->mc_vsregs))
550 			return 1;
551 		current->thread.used_vsr = true;
552 	} else if (current->thread.used_vsr)
553 		for (i = 0; i < 32 ; i++)
554 			current->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
555 #endif /* CONFIG_VSX */
556 	/*
557 	 * force the process to reload the FP registers from
558 	 * current->thread when it next does FP instructions
559 	 */
560 	regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1);
561 
562 #ifdef CONFIG_SPE
563 	/* force the process to reload the spe registers from
564 	   current->thread when it next does spe instructions */
565 	regs->msr &= ~MSR_SPE;
566 	if (msr & MSR_SPE) {
567 		/* restore spe registers from the stack */
568 		if (__copy_from_user(current->thread.evr, &sr->mc_vregs,
569 				     ELF_NEVRREG * sizeof(u32)))
570 			return 1;
571 		current->thread.used_spe = true;
572 	} else if (current->thread.used_spe)
573 		memset(current->thread.evr, 0, ELF_NEVRREG * sizeof(u32));
574 
575 	/* Always get SPEFSCR back */
576 	if (__get_user(current->thread.spefscr, (u32 __user *)&sr->mc_vregs + ELF_NEVRREG))
577 		return 1;
578 #endif /* CONFIG_SPE */
579 
580 	return 0;
581 }
582 
583 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
584 /*
585  * Restore the current user register values from the user stack, except for
586  * MSR, and recheckpoint the original checkpointed register state for processes
587  * in transactions.
588  */
589 static long restore_tm_user_regs(struct pt_regs *regs,
590 				 struct mcontext __user *sr,
591 				 struct mcontext __user *tm_sr)
592 {
593 	long err;
594 	unsigned long msr, msr_hi;
595 #ifdef CONFIG_VSX
596 	int i;
597 #endif
598 
599 	if (tm_suspend_disabled)
600 		return 1;
601 	/*
602 	 * restore general registers but not including MSR or SOFTE. Also
603 	 * take care of keeping r2 (TLS) intact if not a signal.
604 	 * See comment in signal_64.c:restore_tm_sigcontexts();
605 	 * TFHAR is restored from the checkpointed NIP; TEXASR and TFIAR
606 	 * were set by the signal delivery.
607 	 */
608 	err = restore_general_regs(regs, tm_sr);
609 	err |= restore_general_regs(&current->thread.ckpt_regs, sr);
610 
611 	err |= __get_user(current->thread.tm_tfhar, &sr->mc_gregs[PT_NIP]);
612 
613 	err |= __get_user(msr, &sr->mc_gregs[PT_MSR]);
614 	if (err)
615 		return 1;
616 
617 	/* Restore the previous little-endian mode */
618 	regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
619 
620 #ifdef CONFIG_ALTIVEC
621 	regs->msr &= ~MSR_VEC;
622 	if (msr & MSR_VEC) {
623 		/* restore altivec registers from the stack */
624 		if (__copy_from_user(&current->thread.ckvr_state, &sr->mc_vregs,
625 				     sizeof(sr->mc_vregs)) ||
626 		    __copy_from_user(&current->thread.vr_state,
627 				     &tm_sr->mc_vregs,
628 				     sizeof(sr->mc_vregs)))
629 			return 1;
630 		current->thread.used_vr = true;
631 	} else if (current->thread.used_vr) {
632 		memset(&current->thread.vr_state, 0,
633 		       ELF_NVRREG * sizeof(vector128));
634 		memset(&current->thread.ckvr_state, 0,
635 		       ELF_NVRREG * sizeof(vector128));
636 	}
637 
638 	/* Always get VRSAVE back */
639 	if (__get_user(current->thread.ckvrsave,
640 		       (u32 __user *)&sr->mc_vregs[32]) ||
641 	    __get_user(current->thread.vrsave,
642 		       (u32 __user *)&tm_sr->mc_vregs[32]))
643 		return 1;
644 	if (cpu_has_feature(CPU_FTR_ALTIVEC))
645 		mtspr(SPRN_VRSAVE, current->thread.ckvrsave);
646 #endif /* CONFIG_ALTIVEC */
647 
648 	regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1);
649 
650 	if (copy_fpr_from_user(current, &sr->mc_fregs) ||
651 	    copy_ckfpr_from_user(current, &tm_sr->mc_fregs))
652 		return 1;
653 
654 #ifdef CONFIG_VSX
655 	regs->msr &= ~MSR_VSX;
656 	if (msr & MSR_VSX) {
657 		/*
658 		 * Restore altivec registers from the stack to a local
659 		 * buffer, then write this out to the thread_struct
660 		 */
661 		if (copy_vsx_from_user(current, &tm_sr->mc_vsregs) ||
662 		    copy_ckvsx_from_user(current, &sr->mc_vsregs))
663 			return 1;
664 		current->thread.used_vsr = true;
665 	} else if (current->thread.used_vsr)
666 		for (i = 0; i < 32 ; i++) {
667 			current->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
668 			current->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
669 		}
670 #endif /* CONFIG_VSX */
671 
672 #ifdef CONFIG_SPE
673 	/* SPE regs are not checkpointed with TM, so this section is
674 	 * simply the same as in restore_user_regs().
675 	 */
676 	regs->msr &= ~MSR_SPE;
677 	if (msr & MSR_SPE) {
678 		if (__copy_from_user(current->thread.evr, &sr->mc_vregs,
679 				     ELF_NEVRREG * sizeof(u32)))
680 			return 1;
681 		current->thread.used_spe = true;
682 	} else if (current->thread.used_spe)
683 		memset(current->thread.evr, 0, ELF_NEVRREG * sizeof(u32));
684 
685 	/* Always get SPEFSCR back */
686 	if (__get_user(current->thread.spefscr, (u32 __user *)&sr->mc_vregs
687 		       + ELF_NEVRREG))
688 		return 1;
689 #endif /* CONFIG_SPE */
690 
691 	/* Get the top half of the MSR from the user context */
692 	if (__get_user(msr_hi, &tm_sr->mc_gregs[PT_MSR]))
693 		return 1;
694 	msr_hi <<= 32;
695 	/* If TM bits are set to the reserved value, it's an invalid context */
696 	if (MSR_TM_RESV(msr_hi))
697 		return 1;
698 
699 	/*
700 	 * Disabling preemption, since it is unsafe to be preempted
701 	 * with MSR[TS] set without recheckpointing.
702 	 */
703 	preempt_disable();
704 
705 	/*
706 	 * CAUTION:
707 	 * After regs->MSR[TS] being updated, make sure that get_user(),
708 	 * put_user() or similar functions are *not* called. These
709 	 * functions can generate page faults which will cause the process
710 	 * to be de-scheduled with MSR[TS] set but without calling
711 	 * tm_recheckpoint(). This can cause a bug.
712 	 *
713 	 * Pull in the MSR TM bits from the user context
714 	 */
715 	regs->msr = (regs->msr & ~MSR_TS_MASK) | (msr_hi & MSR_TS_MASK);
716 	/* Now, recheckpoint.  This loads up all of the checkpointed (older)
717 	 * registers, including FP and V[S]Rs.  After recheckpointing, the
718 	 * transactional versions should be loaded.
719 	 */
720 	tm_enable();
721 	/* Make sure the transaction is marked as failed */
722 	current->thread.tm_texasr |= TEXASR_FS;
723 	/* This loads the checkpointed FP/VEC state, if used */
724 	tm_recheckpoint(&current->thread);
725 
726 	/* This loads the speculative FP/VEC state, if used */
727 	msr_check_and_set(msr & (MSR_FP | MSR_VEC));
728 	if (msr & MSR_FP) {
729 		load_fp_state(&current->thread.fp_state);
730 		regs->msr |= (MSR_FP | current->thread.fpexc_mode);
731 	}
732 #ifdef CONFIG_ALTIVEC
733 	if (msr & MSR_VEC) {
734 		load_vr_state(&current->thread.vr_state);
735 		regs->msr |= MSR_VEC;
736 	}
737 #endif
738 
739 	preempt_enable();
740 
741 	return 0;
742 }
743 #endif
744 
745 #ifdef CONFIG_PPC64
746 
747 #define copy_siginfo_to_user	copy_siginfo_to_user32
748 
749 #endif /* CONFIG_PPC64 */
750 
751 /*
752  * Set up a signal frame for a "real-time" signal handler
753  * (one which gets siginfo).
754  */
755 int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
756 		       struct task_struct *tsk)
757 {
758 	struct rt_sigframe __user *frame;
759 	struct mcontext __user *mctx;
760 	struct mcontext __user *tm_mctx = NULL;
761 	unsigned long newsp = 0;
762 	unsigned long tramp;
763 	struct pt_regs *regs = tsk->thread.regs;
764 	/* Save the thread's msr before get_tm_stackpointer() changes it */
765 	unsigned long msr = regs->msr;
766 
767 	/* Set up Signal Frame */
768 	frame = get_sigframe(ksig, tsk, sizeof(*frame), 1);
769 	mctx = &frame->uc.uc_mcontext;
770 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
771 	tm_mctx = &frame->uc_transact.uc_mcontext;
772 #endif
773 	if (MSR_TM_ACTIVE(msr))
774 		prepare_save_tm_user_regs();
775 	else
776 		prepare_save_user_regs(1);
777 
778 	if (!user_access_begin(frame, sizeof(*frame)))
779 		goto badframe;
780 
781 	/* Put the siginfo & fill in most of the ucontext */
782 	unsafe_put_user(0, &frame->uc.uc_flags, failed);
783 #ifdef CONFIG_PPC64
784 	unsafe_compat_save_altstack(&frame->uc.uc_stack, regs->gpr[1], failed);
785 #else
786 	unsafe_save_altstack(&frame->uc.uc_stack, regs->gpr[1], failed);
787 #endif
788 	unsafe_put_user(to_user_ptr(&frame->uc.uc_mcontext), &frame->uc.uc_regs, failed);
789 
790 	if (MSR_TM_ACTIVE(msr)) {
791 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
792 		unsafe_put_user((unsigned long)&frame->uc_transact,
793 				&frame->uc.uc_link, failed);
794 		unsafe_put_user((unsigned long)tm_mctx,
795 				&frame->uc_transact.uc_regs, failed);
796 #endif
797 		unsafe_save_tm_user_regs(regs, mctx, tm_mctx, msr, failed);
798 	} else {
799 		unsafe_put_user(0, &frame->uc.uc_link, failed);
800 		unsafe_save_user_regs(regs, mctx, tm_mctx, 1, failed);
801 	}
802 
803 	/* Save user registers on the stack */
804 	if (tsk->mm->context.vdso) {
805 		tramp = VDSO32_SYMBOL(tsk->mm->context.vdso, sigtramp_rt32);
806 	} else {
807 		tramp = (unsigned long)mctx->mc_pad;
808 		/* Set up the sigreturn trampoline: li r0,sigret; sc */
809 		unsafe_put_user(PPC_INST_ADDI + __NR_rt_sigreturn, &mctx->mc_pad[0],
810 				failed);
811 		unsafe_put_user(PPC_INST_SC, &mctx->mc_pad[1], failed);
812 		asm("dcbst %y0; sync; icbi %y0; sync" :: "Z" (mctx->mc_pad[0]));
813 	}
814 	unsafe_put_sigset_t(&frame->uc.uc_sigmask, oldset, failed);
815 
816 	user_access_end();
817 
818 	if (copy_siginfo_to_user(&frame->info, &ksig->info))
819 		goto badframe;
820 
821 	regs->link = tramp;
822 
823 #ifdef CONFIG_PPC_FPU_REGS
824 	tsk->thread.fp_state.fpscr = 0;	/* turn off all fp exceptions */
825 #endif
826 
827 	/* create a stack frame for the caller of the handler */
828 	newsp = ((unsigned long)frame) - (__SIGNAL_FRAMESIZE + 16);
829 	if (put_user(regs->gpr[1], (u32 __user *)newsp))
830 		goto badframe;
831 
832 	/* Fill registers for signal handler */
833 	regs->gpr[1] = newsp;
834 	regs->gpr[3] = ksig->sig;
835 	regs->gpr[4] = (unsigned long)&frame->info;
836 	regs->gpr[5] = (unsigned long)&frame->uc;
837 	regs->gpr[6] = (unsigned long)frame;
838 	regs->nip = (unsigned long) ksig->ka.sa.sa_handler;
839 	/* enter the signal handler in native-endian mode */
840 	regs->msr &= ~MSR_LE;
841 	regs->msr |= (MSR_KERNEL & MSR_LE);
842 	return 0;
843 
844 failed:
845 	user_access_end();
846 
847 badframe:
848 	signal_fault(tsk, regs, "handle_rt_signal32", frame);
849 
850 	return 1;
851 }
852 
853 /*
854  * OK, we're invoking a handler
855  */
856 int handle_signal32(struct ksignal *ksig, sigset_t *oldset,
857 		struct task_struct *tsk)
858 {
859 	struct sigcontext __user *sc;
860 	struct sigframe __user *frame;
861 	struct mcontext __user *mctx;
862 	struct mcontext __user *tm_mctx = NULL;
863 	unsigned long newsp = 0;
864 	unsigned long tramp;
865 	struct pt_regs *regs = tsk->thread.regs;
866 	/* Save the thread's msr before get_tm_stackpointer() changes it */
867 	unsigned long msr = regs->msr;
868 
869 	/* Set up Signal Frame */
870 	frame = get_sigframe(ksig, tsk, sizeof(*frame), 1);
871 	mctx = &frame->mctx;
872 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
873 	tm_mctx = &frame->mctx_transact;
874 #endif
875 	if (MSR_TM_ACTIVE(msr))
876 		prepare_save_tm_user_regs();
877 	else
878 		prepare_save_user_regs(1);
879 
880 	if (!user_access_begin(frame, sizeof(*frame)))
881 		goto badframe;
882 	sc = (struct sigcontext __user *) &frame->sctx;
883 
884 #if _NSIG != 64
885 #error "Please adjust handle_signal()"
886 #endif
887 	unsafe_put_user(to_user_ptr(ksig->ka.sa.sa_handler), &sc->handler, failed);
888 	unsafe_put_user(oldset->sig[0], &sc->oldmask, failed);
889 #ifdef CONFIG_PPC64
890 	unsafe_put_user((oldset->sig[0] >> 32), &sc->_unused[3], failed);
891 #else
892 	unsafe_put_user(oldset->sig[1], &sc->_unused[3], failed);
893 #endif
894 	unsafe_put_user(to_user_ptr(mctx), &sc->regs, failed);
895 	unsafe_put_user(ksig->sig, &sc->signal, failed);
896 
897 	if (MSR_TM_ACTIVE(msr))
898 		unsafe_save_tm_user_regs(regs, mctx, tm_mctx, msr, failed);
899 	else
900 		unsafe_save_user_regs(regs, mctx, tm_mctx, 1, failed);
901 
902 	if (tsk->mm->context.vdso) {
903 		tramp = VDSO32_SYMBOL(tsk->mm->context.vdso, sigtramp32);
904 	} else {
905 		tramp = (unsigned long)mctx->mc_pad;
906 		/* Set up the sigreturn trampoline: li r0,sigret; sc */
907 		unsafe_put_user(PPC_INST_ADDI + __NR_sigreturn, &mctx->mc_pad[0], failed);
908 		unsafe_put_user(PPC_INST_SC, &mctx->mc_pad[1], failed);
909 		asm("dcbst %y0; sync; icbi %y0; sync" :: "Z" (mctx->mc_pad[0]));
910 	}
911 	user_access_end();
912 
913 	regs->link = tramp;
914 
915 #ifdef CONFIG_PPC_FPU_REGS
916 	tsk->thread.fp_state.fpscr = 0;	/* turn off all fp exceptions */
917 #endif
918 
919 	/* create a stack frame for the caller of the handler */
920 	newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE;
921 	if (put_user(regs->gpr[1], (u32 __user *)newsp))
922 		goto badframe;
923 
924 	regs->gpr[1] = newsp;
925 	regs->gpr[3] = ksig->sig;
926 	regs->gpr[4] = (unsigned long) sc;
927 	regs->nip = (unsigned long)ksig->ka.sa.sa_handler;
928 	/* enter the signal handler in native-endian mode */
929 	regs->msr &= ~MSR_LE;
930 	regs->msr |= (MSR_KERNEL & MSR_LE);
931 	return 0;
932 
933 failed:
934 	user_access_end();
935 
936 badframe:
937 	signal_fault(tsk, regs, "handle_signal32", frame);
938 
939 	return 1;
940 }
941 
942 static int do_setcontext(struct ucontext __user *ucp, struct pt_regs *regs, int sig)
943 {
944 	sigset_t set;
945 	struct mcontext __user *mcp;
946 
947 	if (get_sigset_t(&set, &ucp->uc_sigmask))
948 		return -EFAULT;
949 #ifdef CONFIG_PPC64
950 	{
951 		u32 cmcp;
952 
953 		if (__get_user(cmcp, &ucp->uc_regs))
954 			return -EFAULT;
955 		mcp = (struct mcontext __user *)(u64)cmcp;
956 		/* no need to check access_ok(mcp), since mcp < 4GB */
957 	}
958 #else
959 	if (__get_user(mcp, &ucp->uc_regs))
960 		return -EFAULT;
961 	if (!access_ok(mcp, sizeof(*mcp)))
962 		return -EFAULT;
963 #endif
964 	set_current_blocked(&set);
965 	if (restore_user_regs(regs, mcp, sig))
966 		return -EFAULT;
967 
968 	return 0;
969 }
970 
971 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
972 static int do_setcontext_tm(struct ucontext __user *ucp,
973 			    struct ucontext __user *tm_ucp,
974 			    struct pt_regs *regs)
975 {
976 	sigset_t set;
977 	struct mcontext __user *mcp;
978 	struct mcontext __user *tm_mcp;
979 	u32 cmcp;
980 	u32 tm_cmcp;
981 
982 	if (get_sigset_t(&set, &ucp->uc_sigmask))
983 		return -EFAULT;
984 
985 	if (__get_user(cmcp, &ucp->uc_regs) ||
986 	    __get_user(tm_cmcp, &tm_ucp->uc_regs))
987 		return -EFAULT;
988 	mcp = (struct mcontext __user *)(u64)cmcp;
989 	tm_mcp = (struct mcontext __user *)(u64)tm_cmcp;
990 	/* no need to check access_ok(mcp), since mcp < 4GB */
991 
992 	set_current_blocked(&set);
993 	if (restore_tm_user_regs(regs, mcp, tm_mcp))
994 		return -EFAULT;
995 
996 	return 0;
997 }
998 #endif
999 
1000 #ifdef CONFIG_PPC64
1001 COMPAT_SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx,
1002 		       struct ucontext __user *, new_ctx, int, ctx_size)
1003 #else
1004 SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx,
1005 		       struct ucontext __user *, new_ctx, long, ctx_size)
1006 #endif
1007 {
1008 	struct pt_regs *regs = current_pt_regs();
1009 	int ctx_has_vsx_region = 0;
1010 
1011 #ifdef CONFIG_PPC64
1012 	unsigned long new_msr = 0;
1013 
1014 	if (new_ctx) {
1015 		struct mcontext __user *mcp;
1016 		u32 cmcp;
1017 
1018 		/*
1019 		 * Get pointer to the real mcontext.  No need for
1020 		 * access_ok since we are dealing with compat
1021 		 * pointers.
1022 		 */
1023 		if (__get_user(cmcp, &new_ctx->uc_regs))
1024 			return -EFAULT;
1025 		mcp = (struct mcontext __user *)(u64)cmcp;
1026 		if (__get_user(new_msr, &mcp->mc_gregs[PT_MSR]))
1027 			return -EFAULT;
1028 	}
1029 	/*
1030 	 * Check that the context is not smaller than the original
1031 	 * size (with VMX but without VSX)
1032 	 */
1033 	if (ctx_size < UCONTEXTSIZEWITHOUTVSX)
1034 		return -EINVAL;
1035 	/*
1036 	 * If the new context state sets the MSR VSX bits but
1037 	 * it doesn't provide VSX state.
1038 	 */
1039 	if ((ctx_size < sizeof(struct ucontext)) &&
1040 	    (new_msr & MSR_VSX))
1041 		return -EINVAL;
1042 	/* Does the context have enough room to store VSX data? */
1043 	if (ctx_size >= sizeof(struct ucontext))
1044 		ctx_has_vsx_region = 1;
1045 #else
1046 	/* Context size is for future use. Right now, we only make sure
1047 	 * we are passed something we understand
1048 	 */
1049 	if (ctx_size < sizeof(struct ucontext))
1050 		return -EINVAL;
1051 #endif
1052 	if (old_ctx != NULL) {
1053 		struct mcontext __user *mctx;
1054 
1055 		/*
1056 		 * old_ctx might not be 16-byte aligned, in which
1057 		 * case old_ctx->uc_mcontext won't be either.
1058 		 * Because we have the old_ctx->uc_pad2 field
1059 		 * before old_ctx->uc_mcontext, we need to round down
1060 		 * from &old_ctx->uc_mcontext to a 16-byte boundary.
1061 		 */
1062 		mctx = (struct mcontext __user *)
1063 			((unsigned long) &old_ctx->uc_mcontext & ~0xfUL);
1064 		prepare_save_user_regs(ctx_has_vsx_region);
1065 		if (!user_write_access_begin(old_ctx, ctx_size))
1066 			return -EFAULT;
1067 		unsafe_save_user_regs(regs, mctx, NULL, ctx_has_vsx_region, failed);
1068 		unsafe_put_sigset_t(&old_ctx->uc_sigmask, &current->blocked, failed);
1069 		unsafe_put_user(to_user_ptr(mctx), &old_ctx->uc_regs, failed);
1070 		user_write_access_end();
1071 	}
1072 	if (new_ctx == NULL)
1073 		return 0;
1074 	if (!access_ok(new_ctx, ctx_size) ||
1075 	    fault_in_pages_readable((u8 __user *)new_ctx, ctx_size))
1076 		return -EFAULT;
1077 
1078 	/*
1079 	 * If we get a fault copying the context into the kernel's
1080 	 * image of the user's registers, we can't just return -EFAULT
1081 	 * because the user's registers will be corrupted.  For instance
1082 	 * the NIP value may have been updated but not some of the
1083 	 * other registers.  Given that we have done the access_ok
1084 	 * and successfully read the first and last bytes of the region
1085 	 * above, this should only happen in an out-of-memory situation
1086 	 * or if another thread unmaps the region containing the context.
1087 	 * We kill the task with a SIGSEGV in this situation.
1088 	 */
1089 	if (do_setcontext(new_ctx, regs, 0))
1090 		do_exit(SIGSEGV);
1091 
1092 	set_thread_flag(TIF_RESTOREALL);
1093 	return 0;
1094 
1095 failed:
1096 	user_write_access_end();
1097 	return -EFAULT;
1098 }
1099 
1100 #ifdef CONFIG_PPC64
1101 COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
1102 #else
1103 SYSCALL_DEFINE0(rt_sigreturn)
1104 #endif
1105 {
1106 	struct rt_sigframe __user *rt_sf;
1107 	struct pt_regs *regs = current_pt_regs();
1108 	int tm_restore = 0;
1109 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1110 	struct ucontext __user *uc_transact;
1111 	unsigned long msr_hi;
1112 	unsigned long tmp;
1113 #endif
1114 	/* Always make any pending restarted system calls return -EINTR */
1115 	current->restart_block.fn = do_no_restart_syscall;
1116 
1117 	rt_sf = (struct rt_sigframe __user *)
1118 		(regs->gpr[1] + __SIGNAL_FRAMESIZE + 16);
1119 	if (!access_ok(rt_sf, sizeof(*rt_sf)))
1120 		goto bad;
1121 
1122 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1123 	/*
1124 	 * If there is a transactional state then throw it away.
1125 	 * The purpose of a sigreturn is to destroy all traces of the
1126 	 * signal frame, this includes any transactional state created
1127 	 * within in. We only check for suspended as we can never be
1128 	 * active in the kernel, we are active, there is nothing better to
1129 	 * do than go ahead and Bad Thing later.
1130 	 * The cause is not important as there will never be a
1131 	 * recheckpoint so it's not user visible.
1132 	 */
1133 	if (MSR_TM_SUSPENDED(mfmsr()))
1134 		tm_reclaim_current(0);
1135 
1136 	if (__get_user(tmp, &rt_sf->uc.uc_link))
1137 		goto bad;
1138 	uc_transact = (struct ucontext __user *)(uintptr_t)tmp;
1139 	if (uc_transact) {
1140 		u32 cmcp;
1141 		struct mcontext __user *mcp;
1142 
1143 		if (__get_user(cmcp, &uc_transact->uc_regs))
1144 			return -EFAULT;
1145 		mcp = (struct mcontext __user *)(u64)cmcp;
1146 		/* The top 32 bits of the MSR are stashed in the transactional
1147 		 * ucontext. */
1148 		if (__get_user(msr_hi, &mcp->mc_gregs[PT_MSR]))
1149 			goto bad;
1150 
1151 		if (MSR_TM_ACTIVE(msr_hi<<32)) {
1152 			/* Trying to start TM on non TM system */
1153 			if (!cpu_has_feature(CPU_FTR_TM))
1154 				goto bad;
1155 			/* We only recheckpoint on return if we're
1156 			 * transaction.
1157 			 */
1158 			tm_restore = 1;
1159 			if (do_setcontext_tm(&rt_sf->uc, uc_transact, regs))
1160 				goto bad;
1161 		}
1162 	}
1163 	if (!tm_restore) {
1164 		/*
1165 		 * Unset regs->msr because ucontext MSR TS is not
1166 		 * set, and recheckpoint was not called. This avoid
1167 		 * hitting a TM Bad thing at RFID
1168 		 */
1169 		regs->msr &= ~MSR_TS_MASK;
1170 	}
1171 	/* Fall through, for non-TM restore */
1172 #endif
1173 	if (!tm_restore)
1174 		if (do_setcontext(&rt_sf->uc, regs, 1))
1175 			goto bad;
1176 
1177 	/*
1178 	 * It's not clear whether or why it is desirable to save the
1179 	 * sigaltstack setting on signal delivery and restore it on
1180 	 * signal return.  But other architectures do this and we have
1181 	 * always done it up until now so it is probably better not to
1182 	 * change it.  -- paulus
1183 	 */
1184 #ifdef CONFIG_PPC64
1185 	if (compat_restore_altstack(&rt_sf->uc.uc_stack))
1186 		goto bad;
1187 #else
1188 	if (restore_altstack(&rt_sf->uc.uc_stack))
1189 		goto bad;
1190 #endif
1191 	set_thread_flag(TIF_RESTOREALL);
1192 	return 0;
1193 
1194  bad:
1195 	signal_fault(current, regs, "sys_rt_sigreturn", rt_sf);
1196 
1197 	force_sig(SIGSEGV);
1198 	return 0;
1199 }
1200 
1201 #ifdef CONFIG_PPC32
1202 SYSCALL_DEFINE3(debug_setcontext, struct ucontext __user *, ctx,
1203 			 int, ndbg, struct sig_dbg_op __user *, dbg)
1204 {
1205 	struct pt_regs *regs = current_pt_regs();
1206 	struct sig_dbg_op op;
1207 	int i;
1208 	unsigned long new_msr = regs->msr;
1209 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
1210 	unsigned long new_dbcr0 = current->thread.debug.dbcr0;
1211 #endif
1212 
1213 	for (i=0; i<ndbg; i++) {
1214 		if (copy_from_user(&op, dbg + i, sizeof(op)))
1215 			return -EFAULT;
1216 		switch (op.dbg_type) {
1217 		case SIG_DBG_SINGLE_STEPPING:
1218 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
1219 			if (op.dbg_value) {
1220 				new_msr |= MSR_DE;
1221 				new_dbcr0 |= (DBCR0_IDM | DBCR0_IC);
1222 			} else {
1223 				new_dbcr0 &= ~DBCR0_IC;
1224 				if (!DBCR_ACTIVE_EVENTS(new_dbcr0,
1225 						current->thread.debug.dbcr1)) {
1226 					new_msr &= ~MSR_DE;
1227 					new_dbcr0 &= ~DBCR0_IDM;
1228 				}
1229 			}
1230 #else
1231 			if (op.dbg_value)
1232 				new_msr |= MSR_SE;
1233 			else
1234 				new_msr &= ~MSR_SE;
1235 #endif
1236 			break;
1237 		case SIG_DBG_BRANCH_TRACING:
1238 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
1239 			return -EINVAL;
1240 #else
1241 			if (op.dbg_value)
1242 				new_msr |= MSR_BE;
1243 			else
1244 				new_msr &= ~MSR_BE;
1245 #endif
1246 			break;
1247 
1248 		default:
1249 			return -EINVAL;
1250 		}
1251 	}
1252 
1253 	/* We wait until here to actually install the values in the
1254 	   registers so if we fail in the above loop, it will not
1255 	   affect the contents of these registers.  After this point,
1256 	   failure is a problem, anyway, and it's very unlikely unless
1257 	   the user is really doing something wrong. */
1258 	regs->msr = new_msr;
1259 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
1260 	current->thread.debug.dbcr0 = new_dbcr0;
1261 #endif
1262 
1263 	if (!access_ok(ctx, sizeof(*ctx)) ||
1264 	    fault_in_pages_readable((u8 __user *)ctx, sizeof(*ctx)))
1265 		return -EFAULT;
1266 
1267 	/*
1268 	 * If we get a fault copying the context into the kernel's
1269 	 * image of the user's registers, we can't just return -EFAULT
1270 	 * because the user's registers will be corrupted.  For instance
1271 	 * the NIP value may have been updated but not some of the
1272 	 * other registers.  Given that we have done the access_ok
1273 	 * and successfully read the first and last bytes of the region
1274 	 * above, this should only happen in an out-of-memory situation
1275 	 * or if another thread unmaps the region containing the context.
1276 	 * We kill the task with a SIGSEGV in this situation.
1277 	 */
1278 	if (do_setcontext(ctx, regs, 1)) {
1279 		signal_fault(current, regs, "sys_debug_setcontext", ctx);
1280 
1281 		force_sig(SIGSEGV);
1282 		goto out;
1283 	}
1284 
1285 	/*
1286 	 * It's not clear whether or why it is desirable to save the
1287 	 * sigaltstack setting on signal delivery and restore it on
1288 	 * signal return.  But other architectures do this and we have
1289 	 * always done it up until now so it is probably better not to
1290 	 * change it.  -- paulus
1291 	 */
1292 	restore_altstack(&ctx->uc_stack);
1293 
1294 	set_thread_flag(TIF_RESTOREALL);
1295  out:
1296 	return 0;
1297 }
1298 #endif
1299 
1300 /*
1301  * Do a signal return; undo the signal stack.
1302  */
1303 #ifdef CONFIG_PPC64
1304 COMPAT_SYSCALL_DEFINE0(sigreturn)
1305 #else
1306 SYSCALL_DEFINE0(sigreturn)
1307 #endif
1308 {
1309 	struct pt_regs *regs = current_pt_regs();
1310 	struct sigframe __user *sf;
1311 	struct sigcontext __user *sc;
1312 	struct sigcontext sigctx;
1313 	struct mcontext __user *sr;
1314 	void __user *addr;
1315 	sigset_t set;
1316 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1317 	struct mcontext __user *mcp, *tm_mcp;
1318 	unsigned long msr_hi;
1319 #endif
1320 
1321 	/* Always make any pending restarted system calls return -EINTR */
1322 	current->restart_block.fn = do_no_restart_syscall;
1323 
1324 	sf = (struct sigframe __user *)(regs->gpr[1] + __SIGNAL_FRAMESIZE);
1325 	sc = &sf->sctx;
1326 	addr = sc;
1327 	if (copy_from_user(&sigctx, sc, sizeof(sigctx)))
1328 		goto badframe;
1329 
1330 #ifdef CONFIG_PPC64
1331 	/*
1332 	 * Note that PPC32 puts the upper 32 bits of the sigmask in the
1333 	 * unused part of the signal stackframe
1334 	 */
1335 	set.sig[0] = sigctx.oldmask + ((long)(sigctx._unused[3]) << 32);
1336 #else
1337 	set.sig[0] = sigctx.oldmask;
1338 	set.sig[1] = sigctx._unused[3];
1339 #endif
1340 	set_current_blocked(&set);
1341 
1342 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1343 	mcp = (struct mcontext __user *)&sf->mctx;
1344 	tm_mcp = (struct mcontext __user *)&sf->mctx_transact;
1345 	if (__get_user(msr_hi, &tm_mcp->mc_gregs[PT_MSR]))
1346 		goto badframe;
1347 	if (MSR_TM_ACTIVE(msr_hi<<32)) {
1348 		if (!cpu_has_feature(CPU_FTR_TM))
1349 			goto badframe;
1350 		if (restore_tm_user_regs(regs, mcp, tm_mcp))
1351 			goto badframe;
1352 	} else
1353 #endif
1354 	{
1355 		sr = (struct mcontext __user *)from_user_ptr(sigctx.regs);
1356 		addr = sr;
1357 		if (!access_ok(sr, sizeof(*sr))
1358 		    || restore_user_regs(regs, sr, 1))
1359 			goto badframe;
1360 	}
1361 
1362 	set_thread_flag(TIF_RESTOREALL);
1363 	return 0;
1364 
1365 badframe:
1366 	signal_fault(current, regs, "sys_sigreturn", addr);
1367 
1368 	force_sig(SIGSEGV);
1369 	return 0;
1370 }
1371