1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * PowerPC version
4 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
5 *
6 * Derived from "arch/i386/kernel/signal.c"
7 * Copyright (C) 1991, 1992 Linus Torvalds
8 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
9 */
10
11 #include <linux/sched.h>
12 #include <linux/mm.h>
13 #include <linux/smp.h>
14 #include <linux/kernel.h>
15 #include <linux/signal.h>
16 #include <linux/errno.h>
17 #include <linux/wait.h>
18 #include <linux/unistd.h>
19 #include <linux/stddef.h>
20 #include <linux/elf.h>
21 #include <linux/ptrace.h>
22 #include <linux/ratelimit.h>
23 #include <linux/syscalls.h>
24 #include <linux/pagemap.h>
25
26 #include <asm/sigcontext.h>
27 #include <asm/ucontext.h>
28 #include <linux/uaccess.h>
29 #include <asm/unistd.h>
30 #include <asm/cacheflush.h>
31 #include <asm/syscalls.h>
32 #include <asm/vdso.h>
33 #include <asm/switch_to.h>
34 #include <asm/tm.h>
35 #include <asm/asm-prototypes.h>
36
37 #include "signal.h"
38
39
40 #define GP_REGS_SIZE min(sizeof(elf_gregset_t), sizeof(struct pt_regs))
41 #define FP_REGS_SIZE sizeof(elf_fpregset_t)
42
43 #define TRAMP_TRACEBACK 4
44 #define TRAMP_SIZE 7
45
46 /*
47 * When we have signals to deliver, we set up on the user stack,
48 * going down from the original stack pointer:
49 * 1) a rt_sigframe struct which contains the ucontext
50 * 2) a gap of __SIGNAL_FRAMESIZE bytes which acts as a dummy caller
51 * frame for the signal handler.
52 */
53
54 struct rt_sigframe {
55 /* sys_rt_sigreturn requires the ucontext be the first field */
56 struct ucontext uc;
57 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
58 struct ucontext uc_transact;
59 #endif
60 unsigned long _unused[2];
61 unsigned int tramp[TRAMP_SIZE];
62 struct siginfo __user *pinfo;
63 void __user *puc;
64 struct siginfo info;
65 /* New 64 bit little-endian ABI allows redzone of 512 bytes below sp */
66 char abigap[USER_REDZONE_SIZE];
67 } __attribute__ ((aligned (16)));
68
69 /*
70 * This computes a quad word aligned pointer inside the vmx_reserve array
71 * element. For historical reasons sigcontext might not be quad word aligned,
72 * but the location we write the VMX regs to must be. See the comment in
73 * sigcontext for more detail.
74 */
75 #ifdef CONFIG_ALTIVEC
sigcontext_vmx_regs(struct sigcontext __user * sc)76 static elf_vrreg_t __user *sigcontext_vmx_regs(struct sigcontext __user *sc)
77 {
78 return (elf_vrreg_t __user *) (((unsigned long)sc->vmx_reserve + 15) & ~0xful);
79 }
80 #endif
81
prepare_setup_sigcontext(struct task_struct * tsk)82 static void prepare_setup_sigcontext(struct task_struct *tsk)
83 {
84 #ifdef CONFIG_ALTIVEC
85 /* save altivec registers */
86 if (tsk->thread.used_vr)
87 flush_altivec_to_thread(tsk);
88 if (cpu_has_feature(CPU_FTR_ALTIVEC))
89 tsk->thread.vrsave = mfspr(SPRN_VRSAVE);
90 #endif /* CONFIG_ALTIVEC */
91
92 flush_fp_to_thread(tsk);
93
94 #ifdef CONFIG_VSX
95 if (tsk->thread.used_vsr)
96 flush_vsx_to_thread(tsk);
97 #endif /* CONFIG_VSX */
98 }
99
100 /*
101 * Set up the sigcontext for the signal frame.
102 */
103
104 #define unsafe_setup_sigcontext(sc, tsk, signr, set, handler, ctx_has_vsx_region, label)\
105 do { \
106 if (__unsafe_setup_sigcontext(sc, tsk, signr, set, handler, ctx_has_vsx_region))\
107 goto label; \
108 } while (0)
__unsafe_setup_sigcontext(struct sigcontext __user * sc,struct task_struct * tsk,int signr,sigset_t * set,unsigned long handler,int ctx_has_vsx_region)109 static long notrace __unsafe_setup_sigcontext(struct sigcontext __user *sc,
110 struct task_struct *tsk, int signr, sigset_t *set,
111 unsigned long handler, int ctx_has_vsx_region)
112 {
113 /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
114 * process never used altivec yet (MSR_VEC is zero in pt_regs of
115 * the context). This is very important because we must ensure we
116 * don't lose the VRSAVE content that may have been set prior to
117 * the process doing its first vector operation
118 * Userland shall check AT_HWCAP to know whether it can rely on the
119 * v_regs pointer or not
120 */
121 #ifdef CONFIG_ALTIVEC
122 elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);
123 #endif
124 struct pt_regs *regs = tsk->thread.regs;
125 unsigned long msr = regs->msr;
126 /* Force usr to alway see softe as 1 (interrupts enabled) */
127 unsigned long softe = 0x1;
128
129 BUG_ON(tsk != current);
130
131 #ifdef CONFIG_ALTIVEC
132 unsafe_put_user(v_regs, &sc->v_regs, efault_out);
133
134 /* save altivec registers */
135 if (tsk->thread.used_vr) {
136 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */
137 unsafe_copy_to_user(v_regs, &tsk->thread.vr_state,
138 33 * sizeof(vector128), efault_out);
139 /* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg)
140 * contains valid data.
141 */
142 msr |= MSR_VEC;
143 }
144 /* We always copy to/from vrsave, it's 0 if we don't have or don't
145 * use altivec.
146 */
147 unsafe_put_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33], efault_out);
148 #else /* CONFIG_ALTIVEC */
149 unsafe_put_user(0, &sc->v_regs, efault_out);
150 #endif /* CONFIG_ALTIVEC */
151 /* copy fpr regs and fpscr */
152 unsafe_copy_fpr_to_user(&sc->fp_regs, tsk, efault_out);
153
154 /*
155 * Clear the MSR VSX bit to indicate there is no valid state attached
156 * to this context, except in the specific case below where we set it.
157 */
158 msr &= ~MSR_VSX;
159 #ifdef CONFIG_VSX
160 /*
161 * Copy VSX low doubleword to local buffer for formatting,
162 * then out to userspace. Update v_regs to point after the
163 * VMX data.
164 */
165 if (tsk->thread.used_vsr && ctx_has_vsx_region) {
166 v_regs += ELF_NVRREG;
167 unsafe_copy_vsx_to_user(v_regs, tsk, efault_out);
168 /* set MSR_VSX in the MSR value in the frame to
169 * indicate that sc->vs_reg) contains valid data.
170 */
171 msr |= MSR_VSX;
172 }
173 #endif /* CONFIG_VSX */
174 unsafe_put_user(&sc->gp_regs, &sc->regs, efault_out);
175 unsafe_copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE, efault_out);
176 unsafe_put_user(msr, &sc->gp_regs[PT_MSR], efault_out);
177 unsafe_put_user(softe, &sc->gp_regs[PT_SOFTE], efault_out);
178 unsafe_put_user(signr, &sc->signal, efault_out);
179 unsafe_put_user(handler, &sc->handler, efault_out);
180 if (set != NULL)
181 unsafe_put_user(set->sig[0], &sc->oldmask, efault_out);
182
183 return 0;
184
185 efault_out:
186 return -EFAULT;
187 }
188
189 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
190 /*
191 * As above, but Transactional Memory is in use, so deliver sigcontexts
192 * containing checkpointed and transactional register states.
193 *
194 * To do this, we treclaim (done before entering here) to gather both sets of
195 * registers and set up the 'normal' sigcontext registers with rolled-back
196 * register values such that a simple signal handler sees a correct
197 * checkpointed register state. If interested, a TM-aware sighandler can
198 * examine the transactional registers in the 2nd sigcontext to determine the
199 * real origin of the signal.
200 */
setup_tm_sigcontexts(struct sigcontext __user * sc,struct sigcontext __user * tm_sc,struct task_struct * tsk,int signr,sigset_t * set,unsigned long handler,unsigned long msr)201 static long setup_tm_sigcontexts(struct sigcontext __user *sc,
202 struct sigcontext __user *tm_sc,
203 struct task_struct *tsk,
204 int signr, sigset_t *set, unsigned long handler,
205 unsigned long msr)
206 {
207 /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
208 * process never used altivec yet (MSR_VEC is zero in pt_regs of
209 * the context). This is very important because we must ensure we
210 * don't lose the VRSAVE content that may have been set prior to
211 * the process doing its first vector operation
212 * Userland shall check AT_HWCAP to know wether it can rely on the
213 * v_regs pointer or not.
214 */
215 #ifdef CONFIG_ALTIVEC
216 elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);
217 elf_vrreg_t __user *tm_v_regs = sigcontext_vmx_regs(tm_sc);
218 #endif
219 struct pt_regs *regs = tsk->thread.regs;
220 long err = 0;
221
222 BUG_ON(tsk != current);
223
224 BUG_ON(!MSR_TM_ACTIVE(msr));
225
226 WARN_ON(tm_suspend_disabled);
227
228 /* Restore checkpointed FP, VEC, and VSX bits from ckpt_regs as
229 * it contains the correct FP, VEC, VSX state after we treclaimed
230 * the transaction and giveup_all() was called on reclaiming.
231 */
232 msr |= tsk->thread.ckpt_regs.msr & (MSR_FP | MSR_VEC | MSR_VSX);
233
234 #ifdef CONFIG_ALTIVEC
235 err |= __put_user(v_regs, &sc->v_regs);
236 err |= __put_user(tm_v_regs, &tm_sc->v_regs);
237
238 /* save altivec registers */
239 if (tsk->thread.used_vr) {
240 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */
241 err |= __copy_to_user(v_regs, &tsk->thread.ckvr_state,
242 33 * sizeof(vector128));
243 /* If VEC was enabled there are transactional VRs valid too,
244 * else they're a copy of the checkpointed VRs.
245 */
246 if (msr & MSR_VEC)
247 err |= __copy_to_user(tm_v_regs,
248 &tsk->thread.vr_state,
249 33 * sizeof(vector128));
250 else
251 err |= __copy_to_user(tm_v_regs,
252 &tsk->thread.ckvr_state,
253 33 * sizeof(vector128));
254
255 /* set MSR_VEC in the MSR value in the frame to indicate
256 * that sc->v_reg contains valid data.
257 */
258 msr |= MSR_VEC;
259 }
260 /* We always copy to/from vrsave, it's 0 if we don't have or don't
261 * use altivec.
262 */
263 if (cpu_has_feature(CPU_FTR_ALTIVEC))
264 tsk->thread.ckvrsave = mfspr(SPRN_VRSAVE);
265 err |= __put_user(tsk->thread.ckvrsave, (u32 __user *)&v_regs[33]);
266 if (msr & MSR_VEC)
267 err |= __put_user(tsk->thread.vrsave,
268 (u32 __user *)&tm_v_regs[33]);
269 else
270 err |= __put_user(tsk->thread.ckvrsave,
271 (u32 __user *)&tm_v_regs[33]);
272
273 #else /* CONFIG_ALTIVEC */
274 err |= __put_user(0, &sc->v_regs);
275 err |= __put_user(0, &tm_sc->v_regs);
276 #endif /* CONFIG_ALTIVEC */
277
278 /* copy fpr regs and fpscr */
279 err |= copy_ckfpr_to_user(&sc->fp_regs, tsk);
280 if (msr & MSR_FP)
281 err |= copy_fpr_to_user(&tm_sc->fp_regs, tsk);
282 else
283 err |= copy_ckfpr_to_user(&tm_sc->fp_regs, tsk);
284
285 #ifdef CONFIG_VSX
286 /*
287 * Copy VSX low doubleword to local buffer for formatting,
288 * then out to userspace. Update v_regs to point after the
289 * VMX data.
290 */
291 if (tsk->thread.used_vsr) {
292 v_regs += ELF_NVRREG;
293 tm_v_regs += ELF_NVRREG;
294
295 err |= copy_ckvsx_to_user(v_regs, tsk);
296
297 if (msr & MSR_VSX)
298 err |= copy_vsx_to_user(tm_v_regs, tsk);
299 else
300 err |= copy_ckvsx_to_user(tm_v_regs, tsk);
301
302 /* set MSR_VSX in the MSR value in the frame to
303 * indicate that sc->vs_reg) contains valid data.
304 */
305 msr |= MSR_VSX;
306 }
307 #endif /* CONFIG_VSX */
308
309 err |= __put_user(&sc->gp_regs, &sc->regs);
310 err |= __put_user(&tm_sc->gp_regs, &tm_sc->regs);
311 err |= __copy_to_user(&tm_sc->gp_regs, regs, GP_REGS_SIZE);
312 err |= __copy_to_user(&sc->gp_regs,
313 &tsk->thread.ckpt_regs, GP_REGS_SIZE);
314 err |= __put_user(msr, &tm_sc->gp_regs[PT_MSR]);
315 err |= __put_user(msr, &sc->gp_regs[PT_MSR]);
316 err |= __put_user(signr, &sc->signal);
317 err |= __put_user(handler, &sc->handler);
318 if (set != NULL)
319 err |= __put_user(set->sig[0], &sc->oldmask);
320
321 return err;
322 }
323 #endif
324
325 /*
326 * Restore the sigcontext from the signal frame.
327 */
328 #define unsafe_restore_sigcontext(tsk, set, sig, sc, label) do { \
329 if (__unsafe_restore_sigcontext(tsk, set, sig, sc)) \
330 goto label; \
331 } while (0)
__unsafe_restore_sigcontext(struct task_struct * tsk,sigset_t * set,int sig,struct sigcontext __user * sc)332 static long notrace __unsafe_restore_sigcontext(struct task_struct *tsk, sigset_t *set,
333 int sig, struct sigcontext __user *sc)
334 {
335 #ifdef CONFIG_ALTIVEC
336 elf_vrreg_t __user *v_regs;
337 #endif
338 unsigned long save_r13 = 0;
339 unsigned long msr;
340 struct pt_regs *regs = tsk->thread.regs;
341 #ifdef CONFIG_VSX
342 int i;
343 #endif
344
345 BUG_ON(tsk != current);
346
347 /* If this is not a signal return, we preserve the TLS in r13 */
348 if (!sig)
349 save_r13 = regs->gpr[13];
350
351 /* copy the GPRs */
352 unsafe_copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr), efault_out);
353 unsafe_get_user(regs->nip, &sc->gp_regs[PT_NIP], efault_out);
354 /* get MSR separately, transfer the LE bit if doing signal return */
355 unsafe_get_user(msr, &sc->gp_regs[PT_MSR], efault_out);
356 if (sig)
357 regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
358 unsafe_get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3], efault_out);
359 unsafe_get_user(regs->ctr, &sc->gp_regs[PT_CTR], efault_out);
360 unsafe_get_user(regs->link, &sc->gp_regs[PT_LNK], efault_out);
361 unsafe_get_user(regs->xer, &sc->gp_regs[PT_XER], efault_out);
362 unsafe_get_user(regs->ccr, &sc->gp_regs[PT_CCR], efault_out);
363 /* Don't allow userspace to set SOFTE */
364 set_trap_norestart(regs);
365 unsafe_get_user(regs->dar, &sc->gp_regs[PT_DAR], efault_out);
366 unsafe_get_user(regs->dsisr, &sc->gp_regs[PT_DSISR], efault_out);
367 unsafe_get_user(regs->result, &sc->gp_regs[PT_RESULT], efault_out);
368
369 if (!sig)
370 regs->gpr[13] = save_r13;
371 if (set != NULL)
372 unsafe_get_user(set->sig[0], &sc->oldmask, efault_out);
373
374 /*
375 * Force reload of FP/VEC.
376 * This has to be done before copying stuff into tsk->thread.fpr/vr
377 * for the reasons explained in the previous comment.
378 */
379 regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
380
381 #ifdef CONFIG_ALTIVEC
382 unsafe_get_user(v_regs, &sc->v_regs, efault_out);
383 if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128)))
384 return -EFAULT;
385 /* Copy 33 vec registers (vr0..31 and vscr) from the stack */
386 if (v_regs != NULL && (msr & MSR_VEC) != 0) {
387 unsafe_copy_from_user(&tsk->thread.vr_state, v_regs,
388 33 * sizeof(vector128), efault_out);
389 tsk->thread.used_vr = true;
390 } else if (tsk->thread.used_vr) {
391 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128));
392 }
393 /* Always get VRSAVE back */
394 if (v_regs != NULL)
395 unsafe_get_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33], efault_out);
396 else
397 tsk->thread.vrsave = 0;
398 if (cpu_has_feature(CPU_FTR_ALTIVEC))
399 mtspr(SPRN_VRSAVE, tsk->thread.vrsave);
400 #endif /* CONFIG_ALTIVEC */
401 /* restore floating point */
402 unsafe_copy_fpr_from_user(tsk, &sc->fp_regs, efault_out);
403 #ifdef CONFIG_VSX
404 /*
405 * Get additional VSX data. Update v_regs to point after the
406 * VMX data. Copy VSX low doubleword from userspace to local
407 * buffer for formatting, then into the taskstruct.
408 */
409 v_regs += ELF_NVRREG;
410 if ((msr & MSR_VSX) != 0) {
411 unsafe_copy_vsx_from_user(tsk, v_regs, efault_out);
412 tsk->thread.used_vsr = true;
413 } else {
414 for (i = 0; i < 32 ; i++)
415 tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
416 }
417 #endif
418 return 0;
419
420 efault_out:
421 return -EFAULT;
422 }
423
424 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
425 /*
426 * Restore the two sigcontexts from the frame of a transactional processes.
427 */
428
restore_tm_sigcontexts(struct task_struct * tsk,struct sigcontext __user * sc,struct sigcontext __user * tm_sc)429 static long restore_tm_sigcontexts(struct task_struct *tsk,
430 struct sigcontext __user *sc,
431 struct sigcontext __user *tm_sc)
432 {
433 #ifdef CONFIG_ALTIVEC
434 elf_vrreg_t __user *v_regs, *tm_v_regs;
435 #endif
436 unsigned long err = 0;
437 unsigned long msr;
438 struct pt_regs *regs = tsk->thread.regs;
439 #ifdef CONFIG_VSX
440 int i;
441 #endif
442
443 BUG_ON(tsk != current);
444
445 if (tm_suspend_disabled)
446 return -EINVAL;
447
448 /* copy the GPRs */
449 err |= __copy_from_user(regs->gpr, tm_sc->gp_regs, sizeof(regs->gpr));
450 err |= __copy_from_user(&tsk->thread.ckpt_regs, sc->gp_regs,
451 sizeof(regs->gpr));
452
453 /*
454 * TFHAR is restored from the checkpointed 'wound-back' ucontext's NIP.
455 * TEXASR was set by the signal delivery reclaim, as was TFIAR.
456 * Users doing anything abhorrent like thread-switching w/ signals for
457 * TM-Suspended code will have to back TEXASR/TFIAR up themselves.
458 * For the case of getting a signal and simply returning from it,
459 * we don't need to re-copy them here.
460 */
461 err |= __get_user(regs->nip, &tm_sc->gp_regs[PT_NIP]);
462 err |= __get_user(tsk->thread.tm_tfhar, &sc->gp_regs[PT_NIP]);
463
464 /* get MSR separately, transfer the LE bit if doing signal return */
465 err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
466 /* Don't allow reserved mode. */
467 if (MSR_TM_RESV(msr))
468 return -EINVAL;
469
470 /* pull in MSR LE from user context */
471 regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
472
473 /* The following non-GPR non-FPR non-VR state is also checkpointed: */
474 err |= __get_user(regs->ctr, &tm_sc->gp_regs[PT_CTR]);
475 err |= __get_user(regs->link, &tm_sc->gp_regs[PT_LNK]);
476 err |= __get_user(regs->xer, &tm_sc->gp_regs[PT_XER]);
477 err |= __get_user(regs->ccr, &tm_sc->gp_regs[PT_CCR]);
478 err |= __get_user(tsk->thread.ckpt_regs.ctr,
479 &sc->gp_regs[PT_CTR]);
480 err |= __get_user(tsk->thread.ckpt_regs.link,
481 &sc->gp_regs[PT_LNK]);
482 err |= __get_user(tsk->thread.ckpt_regs.xer,
483 &sc->gp_regs[PT_XER]);
484 err |= __get_user(tsk->thread.ckpt_regs.ccr,
485 &sc->gp_regs[PT_CCR]);
486 /* Don't allow userspace to set SOFTE */
487 set_trap_norestart(regs);
488 /* These regs are not checkpointed; they can go in 'regs'. */
489 err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
490 err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
491 err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
492
493 /*
494 * Force reload of FP/VEC.
495 * This has to be done before copying stuff into tsk->thread.fpr/vr
496 * for the reasons explained in the previous comment.
497 */
498 regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
499
500 #ifdef CONFIG_ALTIVEC
501 err |= __get_user(v_regs, &sc->v_regs);
502 err |= __get_user(tm_v_regs, &tm_sc->v_regs);
503 if (err)
504 return err;
505 if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128)))
506 return -EFAULT;
507 if (tm_v_regs && !access_ok(tm_v_regs, 34 * sizeof(vector128)))
508 return -EFAULT;
509 /* Copy 33 vec registers (vr0..31 and vscr) from the stack */
510 if (v_regs != NULL && tm_v_regs != NULL && (msr & MSR_VEC) != 0) {
511 err |= __copy_from_user(&tsk->thread.ckvr_state, v_regs,
512 33 * sizeof(vector128));
513 err |= __copy_from_user(&tsk->thread.vr_state, tm_v_regs,
514 33 * sizeof(vector128));
515 current->thread.used_vr = true;
516 }
517 else if (tsk->thread.used_vr) {
518 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128));
519 memset(&tsk->thread.ckvr_state, 0, 33 * sizeof(vector128));
520 }
521 /* Always get VRSAVE back */
522 if (v_regs != NULL && tm_v_regs != NULL) {
523 err |= __get_user(tsk->thread.ckvrsave,
524 (u32 __user *)&v_regs[33]);
525 err |= __get_user(tsk->thread.vrsave,
526 (u32 __user *)&tm_v_regs[33]);
527 }
528 else {
529 tsk->thread.vrsave = 0;
530 tsk->thread.ckvrsave = 0;
531 }
532 if (cpu_has_feature(CPU_FTR_ALTIVEC))
533 mtspr(SPRN_VRSAVE, tsk->thread.vrsave);
534 #endif /* CONFIG_ALTIVEC */
535 /* restore floating point */
536 err |= copy_fpr_from_user(tsk, &tm_sc->fp_regs);
537 err |= copy_ckfpr_from_user(tsk, &sc->fp_regs);
538 #ifdef CONFIG_VSX
539 /*
540 * Get additional VSX data. Update v_regs to point after the
541 * VMX data. Copy VSX low doubleword from userspace to local
542 * buffer for formatting, then into the taskstruct.
543 */
544 if (v_regs && ((msr & MSR_VSX) != 0)) {
545 v_regs += ELF_NVRREG;
546 tm_v_regs += ELF_NVRREG;
547 err |= copy_vsx_from_user(tsk, tm_v_regs);
548 err |= copy_ckvsx_from_user(tsk, v_regs);
549 tsk->thread.used_vsr = true;
550 } else {
551 for (i = 0; i < 32 ; i++) {
552 tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
553 tsk->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
554 }
555 }
556 #endif
557 tm_enable();
558 /* Make sure the transaction is marked as failed */
559 tsk->thread.tm_texasr |= TEXASR_FS;
560
561 /*
562 * Disabling preemption, since it is unsafe to be preempted
563 * with MSR[TS] set without recheckpointing.
564 */
565 preempt_disable();
566
567 /* pull in MSR TS bits from user context */
568 regs->msr |= msr & MSR_TS_MASK;
569
570 /*
571 * Ensure that TM is enabled in regs->msr before we leave the signal
572 * handler. It could be the case that (a) user disabled the TM bit
573 * through the manipulation of the MSR bits in uc_mcontext or (b) the
574 * TM bit was disabled because a sufficient number of context switches
575 * happened whilst in the signal handler and load_tm overflowed,
576 * disabling the TM bit. In either case we can end up with an illegal
577 * TM state leading to a TM Bad Thing when we return to userspace.
578 *
579 * CAUTION:
580 * After regs->MSR[TS] being updated, make sure that get_user(),
581 * put_user() or similar functions are *not* called. These
582 * functions can generate page faults which will cause the process
583 * to be de-scheduled with MSR[TS] set but without calling
584 * tm_recheckpoint(). This can cause a bug.
585 */
586 regs->msr |= MSR_TM;
587
588 /* This loads the checkpointed FP/VEC state, if used */
589 tm_recheckpoint(&tsk->thread);
590
591 msr_check_and_set(msr & (MSR_FP | MSR_VEC));
592 if (msr & MSR_FP) {
593 load_fp_state(&tsk->thread.fp_state);
594 regs->msr |= (MSR_FP | tsk->thread.fpexc_mode);
595 }
596 if (msr & MSR_VEC) {
597 load_vr_state(&tsk->thread.vr_state);
598 regs->msr |= MSR_VEC;
599 }
600
601 preempt_enable();
602
603 return err;
604 }
605 #else /* !CONFIG_PPC_TRANSACTIONAL_MEM */
restore_tm_sigcontexts(struct task_struct * tsk,struct sigcontext __user * sc,struct sigcontext __user * tm_sc)606 static long restore_tm_sigcontexts(struct task_struct *tsk, struct sigcontext __user *sc,
607 struct sigcontext __user *tm_sc)
608 {
609 return -EINVAL;
610 }
611 #endif
612
613 /*
614 * Setup the trampoline code on the stack
615 */
setup_trampoline(unsigned int syscall,unsigned int __user * tramp)616 static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
617 {
618 int i;
619 long err = 0;
620
621 /* bctrl # call the handler */
622 err |= __put_user(PPC_INST_BCTRL, &tramp[0]);
623 /* addi r1, r1, __SIGNAL_FRAMESIZE # Pop the dummy stackframe */
624 err |= __put_user(PPC_INST_ADDI | __PPC_RT(R1) | __PPC_RA(R1) |
625 (__SIGNAL_FRAMESIZE & 0xffff), &tramp[1]);
626 /* li r0, __NR_[rt_]sigreturn| */
627 err |= __put_user(PPC_INST_ADDI | (syscall & 0xffff), &tramp[2]);
628 /* sc */
629 err |= __put_user(PPC_INST_SC, &tramp[3]);
630
631 /* Minimal traceback info */
632 for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)
633 err |= __put_user(0, &tramp[i]);
634
635 if (!err)
636 flush_icache_range((unsigned long) &tramp[0],
637 (unsigned long) &tramp[TRAMP_SIZE]);
638
639 return err;
640 }
641
642 /*
643 * Userspace code may pass a ucontext which doesn't include VSX added
644 * at the end. We need to check for this case.
645 */
646 #define UCONTEXTSIZEWITHOUTVSX \
647 (sizeof(struct ucontext) - 32*sizeof(long))
648
649 /*
650 * Handle {get,set,swap}_context operations
651 */
SYSCALL_DEFINE3(swapcontext,struct ucontext __user *,old_ctx,struct ucontext __user *,new_ctx,long,ctx_size)652 SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx,
653 struct ucontext __user *, new_ctx, long, ctx_size)
654 {
655 sigset_t set;
656 unsigned long new_msr = 0;
657 int ctx_has_vsx_region = 0;
658
659 if (new_ctx &&
660 get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR]))
661 return -EFAULT;
662 /*
663 * Check that the context is not smaller than the original
664 * size (with VMX but without VSX)
665 */
666 if (ctx_size < UCONTEXTSIZEWITHOUTVSX)
667 return -EINVAL;
668 /*
669 * If the new context state sets the MSR VSX bits but
670 * it doesn't provide VSX state.
671 */
672 if ((ctx_size < sizeof(struct ucontext)) &&
673 (new_msr & MSR_VSX))
674 return -EINVAL;
675 /* Does the context have enough room to store VSX data? */
676 if (ctx_size >= sizeof(struct ucontext))
677 ctx_has_vsx_region = 1;
678
679 if (old_ctx != NULL) {
680 prepare_setup_sigcontext(current);
681 if (!user_write_access_begin(old_ctx, ctx_size))
682 return -EFAULT;
683
684 unsafe_setup_sigcontext(&old_ctx->uc_mcontext, current, 0, NULL,
685 0, ctx_has_vsx_region, efault_out);
686 unsafe_copy_to_user(&old_ctx->uc_sigmask, ¤t->blocked,
687 sizeof(sigset_t), efault_out);
688
689 user_write_access_end();
690 }
691 if (new_ctx == NULL)
692 return 0;
693 if (!access_ok(new_ctx, ctx_size) ||
694 fault_in_pages_readable((u8 __user *)new_ctx, ctx_size))
695 return -EFAULT;
696
697 /*
698 * If we get a fault copying the context into the kernel's
699 * image of the user's registers, we can't just return -EFAULT
700 * because the user's registers will be corrupted. For instance
701 * the NIP value may have been updated but not some of the
702 * other registers. Given that we have done the access_ok
703 * and successfully read the first and last bytes of the region
704 * above, this should only happen in an out-of-memory situation
705 * or if another thread unmaps the region containing the context.
706 * We kill the task with a SIGSEGV in this situation.
707 */
708
709 if (__get_user_sigset(&set, &new_ctx->uc_sigmask))
710 do_exit(SIGSEGV);
711 set_current_blocked(&set);
712
713 if (!user_read_access_begin(new_ctx, ctx_size))
714 return -EFAULT;
715 if (__unsafe_restore_sigcontext(current, NULL, 0, &new_ctx->uc_mcontext)) {
716 user_read_access_end();
717 do_exit(SIGSEGV);
718 }
719 user_read_access_end();
720
721 /* This returns like rt_sigreturn */
722 set_thread_flag(TIF_RESTOREALL);
723 return 0;
724
725 efault_out:
726 user_write_access_end();
727 return -EFAULT;
728 }
729
730
731 /*
732 * Do a signal return; undo the signal stack.
733 */
734
SYSCALL_DEFINE0(rt_sigreturn)735 SYSCALL_DEFINE0(rt_sigreturn)
736 {
737 struct pt_regs *regs = current_pt_regs();
738 struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
739 sigset_t set;
740 unsigned long msr;
741
742 /* Always make any pending restarted system calls return -EINTR */
743 current->restart_block.fn = do_no_restart_syscall;
744
745 if (!access_ok(uc, sizeof(*uc)))
746 goto badframe;
747
748 if (__get_user_sigset(&set, &uc->uc_sigmask))
749 goto badframe;
750 set_current_blocked(&set);
751
752 if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM)) {
753 /*
754 * If there is a transactional state then throw it away.
755 * The purpose of a sigreturn is to destroy all traces of the
756 * signal frame, this includes any transactional state created
757 * within in. We only check for suspended as we can never be
758 * active in the kernel, we are active, there is nothing better to
759 * do than go ahead and Bad Thing later.
760 * The cause is not important as there will never be a
761 * recheckpoint so it's not user visible.
762 */
763 if (MSR_TM_SUSPENDED(mfmsr()))
764 tm_reclaim_current(0);
765
766 /*
767 * Disable MSR[TS] bit also, so, if there is an exception in the
768 * code below (as a page fault in copy_ckvsx_to_user()), it does
769 * not recheckpoint this task if there was a context switch inside
770 * the exception.
771 *
772 * A major page fault can indirectly call schedule(). A reschedule
773 * process in the middle of an exception can have a side effect
774 * (Changing the CPU MSR[TS] state), since schedule() is called
775 * with the CPU MSR[TS] disable and returns with MSR[TS]=Suspended
776 * (switch_to() calls tm_recheckpoint() for the 'new' process). In
777 * this case, the process continues to be the same in the CPU, but
778 * the CPU state just changed.
779 *
780 * This can cause a TM Bad Thing, since the MSR in the stack will
781 * have the MSR[TS]=0, and this is what will be used to RFID.
782 *
783 * Clearing MSR[TS] state here will avoid a recheckpoint if there
784 * is any process reschedule in kernel space. The MSR[TS] state
785 * does not need to be saved also, since it will be replaced with
786 * the MSR[TS] that came from user context later, at
787 * restore_tm_sigcontexts.
788 */
789 regs->msr &= ~MSR_TS_MASK;
790
791 if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR]))
792 goto badframe;
793 }
794
795 if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM) && MSR_TM_ACTIVE(msr)) {
796 /* We recheckpoint on return. */
797 struct ucontext __user *uc_transact;
798
799 /* Trying to start TM on non TM system */
800 if (!cpu_has_feature(CPU_FTR_TM))
801 goto badframe;
802
803 if (__get_user(uc_transact, &uc->uc_link))
804 goto badframe;
805 if (restore_tm_sigcontexts(current, &uc->uc_mcontext,
806 &uc_transact->uc_mcontext))
807 goto badframe;
808 } else {
809 /*
810 * Fall through, for non-TM restore
811 *
812 * Unset MSR[TS] on the thread regs since MSR from user
813 * context does not have MSR active, and recheckpoint was
814 * not called since restore_tm_sigcontexts() was not called
815 * also.
816 *
817 * If not unsetting it, the code can RFID to userspace with
818 * MSR[TS] set, but without CPU in the proper state,
819 * causing a TM bad thing.
820 */
821 current->thread.regs->msr &= ~MSR_TS_MASK;
822 if (!user_read_access_begin(&uc->uc_mcontext, sizeof(uc->uc_mcontext)))
823 goto badframe;
824
825 unsafe_restore_sigcontext(current, NULL, 1, &uc->uc_mcontext,
826 badframe_block);
827
828 user_read_access_end();
829 }
830
831 if (restore_altstack(&uc->uc_stack))
832 goto badframe;
833
834 set_thread_flag(TIF_RESTOREALL);
835 return 0;
836
837 badframe_block:
838 user_read_access_end();
839 badframe:
840 signal_fault(current, regs, "rt_sigreturn", uc);
841
842 force_sig(SIGSEGV);
843 return 0;
844 }
845
handle_rt_signal64(struct ksignal * ksig,sigset_t * set,struct task_struct * tsk)846 int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
847 struct task_struct *tsk)
848 {
849 struct rt_sigframe __user *frame;
850 unsigned long newsp = 0;
851 long err = 0;
852 struct pt_regs *regs = tsk->thread.regs;
853 /* Save the thread's msr before get_tm_stackpointer() changes it */
854 unsigned long msr = regs->msr;
855
856 frame = get_sigframe(ksig, tsk, sizeof(*frame), 0);
857
858 /*
859 * This only applies when calling unsafe_setup_sigcontext() and must be
860 * called before opening the uaccess window.
861 */
862 if (!MSR_TM_ACTIVE(msr))
863 prepare_setup_sigcontext(tsk);
864
865 if (!user_write_access_begin(frame, sizeof(*frame)))
866 goto badframe;
867
868 unsafe_put_user(&frame->info, &frame->pinfo, badframe_block);
869 unsafe_put_user(&frame->uc, &frame->puc, badframe_block);
870
871 /* Create the ucontext. */
872 unsafe_put_user(0, &frame->uc.uc_flags, badframe_block);
873 unsafe_save_altstack(&frame->uc.uc_stack, regs->gpr[1], badframe_block);
874
875 if (MSR_TM_ACTIVE(msr)) {
876 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
877 /* The ucontext_t passed to userland points to the second
878 * ucontext_t (for transactional state) with its uc_link ptr.
879 */
880 unsafe_put_user(&frame->uc_transact, &frame->uc.uc_link, badframe_block);
881
882 user_write_access_end();
883
884 err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext,
885 &frame->uc_transact.uc_mcontext,
886 tsk, ksig->sig, NULL,
887 (unsigned long)ksig->ka.sa.sa_handler,
888 msr);
889
890 if (!user_write_access_begin(&frame->uc.uc_sigmask,
891 sizeof(frame->uc.uc_sigmask)))
892 goto badframe;
893
894 #endif
895 } else {
896 unsafe_put_user(0, &frame->uc.uc_link, badframe_block);
897 unsafe_setup_sigcontext(&frame->uc.uc_mcontext, tsk, ksig->sig,
898 NULL, (unsigned long)ksig->ka.sa.sa_handler,
899 1, badframe_block);
900 }
901
902 unsafe_copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set), badframe_block);
903 user_write_access_end();
904
905 /* Make sure signal handler doesn't get spurious FP exceptions */
906 tsk->thread.fp_state.fpscr = 0;
907
908 /* Set up to return from userspace. */
909 if (tsk->mm->context.vdso) {
910 regs->nip = VDSO64_SYMBOL(tsk->mm->context.vdso, sigtramp_rt64);
911 } else {
912 err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
913 if (err)
914 goto badframe;
915 regs->nip = (unsigned long) &frame->tramp[0];
916 }
917
918
919 /* Save the siginfo outside of the unsafe block. */
920 if (copy_siginfo_to_user(&frame->info, &ksig->info))
921 goto badframe;
922
923 /* Allocate a dummy caller frame for the signal handler. */
924 newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE;
925 err |= put_user(regs->gpr[1], (unsigned long __user *)newsp);
926
927 /* Set up "regs" so we "return" to the signal handler. */
928 if (is_elf2_task()) {
929 regs->ctr = (unsigned long) ksig->ka.sa.sa_handler;
930 regs->gpr[12] = regs->ctr;
931 } else {
932 /* Handler is *really* a pointer to the function descriptor for
933 * the signal routine. The first entry in the function
934 * descriptor is the entry address of signal and the second
935 * entry is the TOC value we need to use.
936 */
937 func_descr_t __user *funct_desc_ptr =
938 (func_descr_t __user *) ksig->ka.sa.sa_handler;
939
940 err |= get_user(regs->ctr, &funct_desc_ptr->entry);
941 err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
942 }
943
944 /* enter the signal handler in native-endian mode */
945 regs->msr &= ~MSR_LE;
946 regs->msr |= (MSR_KERNEL & MSR_LE);
947 regs->gpr[1] = newsp;
948 regs->gpr[3] = ksig->sig;
949 regs->result = 0;
950 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
951 err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo);
952 err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc);
953 regs->gpr[6] = (unsigned long) frame;
954 } else {
955 regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext;
956 }
957 if (err)
958 goto badframe;
959
960 return 0;
961
962 badframe_block:
963 user_write_access_end();
964 badframe:
965 signal_fault(current, regs, "handle_rt_signal64", frame);
966
967 return 1;
968 }
969