1 // SPDX-License-Identifier: GPL-2.0-or-later
4 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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
11 #include <linux/sched.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>
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>
33 #include <asm/switch_to.h>
35 #include <asm/asm-prototypes.h>
40 #define GP_REGS_SIZE min(sizeof(elf_gregset_t), sizeof(struct pt_regs))
41 #define FP_REGS_SIZE sizeof(elf_fpregset_t)
43 #define TRAMP_TRACEBACK 4
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.
55 /* sys_rt_sigreturn requires the ucontext be the first field */
57 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
58 struct ucontext uc_transact;
60 unsigned long _unused[2];
61 unsigned int tramp[TRAMP_SIZE];
62 struct siginfo __user *pinfo;
65 /* New 64 bit little-endian ABI allows redzone of 512 bytes below sp */
66 char abigap[USER_REDZONE_SIZE];
67 } __attribute__ ((aligned (16)));
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.
76 static elf_vrreg_t __user *sigcontext_vmx_regs(struct sigcontext __user *sc)
78 return (elf_vrreg_t __user *) (((unsigned long)sc->vmx_reserve + 15) & ~0xful);
82 static void prepare_setup_sigcontext(struct task_struct *tsk)
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 */
92 flush_fp_to_thread(tsk);
95 if (tsk->thread.used_vsr)
96 flush_vsx_to_thread(tsk);
97 #endif /* CONFIG_VSX */
101 * Set up the sigcontext for the signal frame.
104 #define unsafe_setup_sigcontext(sc, tsk, signr, set, handler, ctx_has_vsx_region, label)\
106 if (__unsafe_setup_sigcontext(sc, tsk, signr, set, handler, 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)
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
121 #ifdef CONFIG_ALTIVEC
122 elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);
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;
129 BUG_ON(tsk != current);
131 #ifdef CONFIG_ALTIVEC
132 unsafe_put_user(v_regs, &sc->v_regs, efault_out);
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.
144 /* We always copy to/from vrsave, it's 0 if we don't have or don't
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);
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.
161 * Copy VSX low doubleword to local buffer for formatting,
162 * then out to userspace. Update v_regs to point after the
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.
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);
181 unsafe_put_user(set->sig[0], &sc->oldmask, efault_out);
189 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
191 * As above, but Transactional Memory is in use, so deliver sigcontexts
192 * containing checkpointed and transactional register states.
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.
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,
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.
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);
219 struct pt_regs *regs = tsk->thread.regs;
222 BUG_ON(tsk != current);
224 BUG_ON(!MSR_TM_ACTIVE(msr));
226 WARN_ON(tm_suspend_disabled);
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.
232 msr |= tsk->thread.ckpt_regs.msr & (MSR_FP | MSR_VEC | MSR_VSX);
234 #ifdef CONFIG_ALTIVEC
235 err |= __put_user(v_regs, &sc->v_regs);
236 err |= __put_user(tm_v_regs, &tm_sc->v_regs);
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.
247 err |= __copy_to_user(tm_v_regs,
248 &tsk->thread.vr_state,
249 33 * sizeof(vector128));
251 err |= __copy_to_user(tm_v_regs,
252 &tsk->thread.ckvr_state,
253 33 * sizeof(vector128));
255 /* set MSR_VEC in the MSR value in the frame to indicate
256 * that sc->v_reg contains valid data.
260 /* We always copy to/from vrsave, it's 0 if we don't have or don't
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]);
267 err |= __put_user(tsk->thread.vrsave,
268 (u32 __user *)&tm_v_regs[33]);
270 err |= __put_user(tsk->thread.ckvrsave,
271 (u32 __user *)&tm_v_regs[33]);
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 */
278 /* copy fpr regs and fpscr */
279 err |= copy_ckfpr_to_user(&sc->fp_regs, tsk);
281 err |= copy_fpr_to_user(&tm_sc->fp_regs, tsk);
283 err |= copy_ckfpr_to_user(&tm_sc->fp_regs, tsk);
287 * Copy VSX low doubleword to local buffer for formatting,
288 * then out to userspace. Update v_regs to point after the
291 if (tsk->thread.used_vsr) {
292 v_regs += ELF_NVRREG;
293 tm_v_regs += ELF_NVRREG;
295 err |= copy_ckvsx_to_user(v_regs, tsk);
298 err |= copy_vsx_to_user(tm_v_regs, tsk);
300 err |= copy_ckvsx_to_user(tm_v_regs, tsk);
302 /* set MSR_VSX in the MSR value in the frame to
303 * indicate that sc->vs_reg) contains valid data.
307 #endif /* CONFIG_VSX */
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);
319 err |= __put_user(set->sig[0], &sc->oldmask);
326 * Restore the sigcontext from the signal frame.
328 #define unsafe_restore_sigcontext(tsk, set, sig, sc, label) do { \
329 if (__unsafe_restore_sigcontext(tsk, set, sig, sc)) \
332 static long notrace __unsafe_restore_sigcontext(struct task_struct *tsk, sigset_t *set,
333 int sig, struct sigcontext __user *sc)
335 #ifdef CONFIG_ALTIVEC
336 elf_vrreg_t __user *v_regs;
338 unsigned long save_r13 = 0;
340 struct pt_regs *regs = tsk->thread.regs;
345 BUG_ON(tsk != current);
347 /* If this is not a signal return, we preserve the TLS in r13 */
349 save_r13 = regs->gpr[13];
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);
357 regs_set_return_msr(regs, (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);
370 regs->gpr[13] = save_r13;
372 unsafe_get_user(set->sig[0], &sc->oldmask, efault_out);
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.
379 regs_set_return_msr(regs, regs->msr & ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX));
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)))
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));
393 /* Always get VRSAVE back */
395 unsafe_get_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33], efault_out);
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);
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.
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;
414 for (i = 0; i < 32 ; i++)
415 tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
424 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
426 * Restore the two sigcontexts from the frame of a transactional processes.
429 static long restore_tm_sigcontexts(struct task_struct *tsk,
430 struct sigcontext __user *sc,
431 struct sigcontext __user *tm_sc)
433 #ifdef CONFIG_ALTIVEC
434 elf_vrreg_t __user *v_regs, *tm_v_regs;
436 unsigned long err = 0;
438 struct pt_regs *regs = tsk->thread.regs;
443 BUG_ON(tsk != current);
445 if (tm_suspend_disabled)
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,
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.
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]);
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))
470 /* pull in MSR LE from user context */
471 regs_set_return_msr(regs, (regs->msr & ~MSR_LE) | (msr & MSR_LE));
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]);
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.
498 regs_set_return_msr(regs, regs->msr & ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX));
500 #ifdef CONFIG_ALTIVEC
501 err |= __get_user(v_regs, &sc->v_regs);
502 err |= __get_user(tm_v_regs, &tm_sc->v_regs);
505 if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128)))
507 if (tm_v_regs && !access_ok(tm_v_regs, 34 * sizeof(vector128)))
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;
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));
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]);
529 tsk->thread.vrsave = 0;
530 tsk->thread.ckvrsave = 0;
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);
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.
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;
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;
558 /* Make sure the transaction is marked as failed */
559 tsk->thread.tm_texasr |= TEXASR_FS;
562 * Disabling preemption, since it is unsafe to be preempted
563 * with MSR[TS] set without recheckpointing.
567 /* pull in MSR TS bits from user context */
568 regs_set_return_msr(regs, regs->msr | (msr & MSR_TS_MASK));
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.
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.
586 regs_set_return_msr(regs, regs->msr | MSR_TM);
588 /* This loads the checkpointed FP/VEC state, if used */
589 tm_recheckpoint(&tsk->thread);
591 msr_check_and_set(msr & (MSR_FP | MSR_VEC));
593 load_fp_state(&tsk->thread.fp_state);
594 regs_set_return_msr(regs, regs->msr | (MSR_FP | tsk->thread.fpexc_mode));
597 load_vr_state(&tsk->thread.vr_state);
598 regs_set_return_msr(regs, regs->msr | MSR_VEC);
605 #else /* !CONFIG_PPC_TRANSACTIONAL_MEM */
606 static long restore_tm_sigcontexts(struct task_struct *tsk, struct sigcontext __user *sc,
607 struct sigcontext __user *tm_sc)
614 * Setup the trampoline code on the stack
616 static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
621 /* Call the handler and pop the dummy stackframe*/
622 err |= __put_user(PPC_RAW_BCTRL(), &tramp[0]);
623 err |= __put_user(PPC_RAW_ADDI(_R1, _R1, __SIGNAL_FRAMESIZE), &tramp[1]);
625 err |= __put_user(PPC_RAW_LI(_R0, syscall), &tramp[2]);
626 err |= __put_user(PPC_RAW_SC(), &tramp[3]);
628 /* Minimal traceback info */
629 for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)
630 err |= __put_user(0, &tramp[i]);
633 flush_icache_range((unsigned long) &tramp[0],
634 (unsigned long) &tramp[TRAMP_SIZE]);
640 * Userspace code may pass a ucontext which doesn't include VSX added
641 * at the end. We need to check for this case.
643 #define UCONTEXTSIZEWITHOUTVSX \
644 (sizeof(struct ucontext) - 32*sizeof(long))
647 * Handle {get,set,swap}_context operations
649 SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx,
650 struct ucontext __user *, new_ctx, long, ctx_size)
653 unsigned long new_msr = 0;
654 int ctx_has_vsx_region = 0;
657 get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR]))
660 * Check that the context is not smaller than the original
661 * size (with VMX but without VSX)
663 if (ctx_size < UCONTEXTSIZEWITHOUTVSX)
666 * If the new context state sets the MSR VSX bits but
667 * it doesn't provide VSX state.
669 if ((ctx_size < sizeof(struct ucontext)) &&
672 /* Does the context have enough room to store VSX data? */
673 if (ctx_size >= sizeof(struct ucontext))
674 ctx_has_vsx_region = 1;
676 if (old_ctx != NULL) {
677 prepare_setup_sigcontext(current);
678 if (!user_write_access_begin(old_ctx, ctx_size))
681 unsafe_setup_sigcontext(&old_ctx->uc_mcontext, current, 0, NULL,
682 0, ctx_has_vsx_region, efault_out);
683 unsafe_copy_to_user(&old_ctx->uc_sigmask, ¤t->blocked,
684 sizeof(sigset_t), efault_out);
686 user_write_access_end();
690 if (!access_ok(new_ctx, ctx_size) ||
691 fault_in_readable((char __user *)new_ctx, ctx_size))
695 * If we get a fault copying the context into the kernel's
696 * image of the user's registers, we can't just return -EFAULT
697 * because the user's registers will be corrupted. For instance
698 * the NIP value may have been updated but not some of the
699 * other registers. Given that we have done the access_ok
700 * and successfully read the first and last bytes of the region
701 * above, this should only happen in an out-of-memory situation
702 * or if another thread unmaps the region containing the context.
703 * We kill the task with a SIGSEGV in this situation.
706 if (__get_user_sigset(&set, &new_ctx->uc_sigmask)) {
707 force_exit_sig(SIGSEGV);
710 set_current_blocked(&set);
712 if (!user_read_access_begin(new_ctx, ctx_size))
714 if (__unsafe_restore_sigcontext(current, NULL, 0, &new_ctx->uc_mcontext)) {
715 user_read_access_end();
716 force_exit_sig(SIGSEGV);
719 user_read_access_end();
721 /* This returns like rt_sigreturn */
722 set_thread_flag(TIF_RESTOREALL);
727 user_write_access_end();
733 * Do a signal return; undo the signal stack.
736 SYSCALL_DEFINE0(rt_sigreturn)
738 struct pt_regs *regs = current_pt_regs();
739 struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
743 /* Always make any pending restarted system calls return -EINTR */
744 current->restart_block.fn = do_no_restart_syscall;
746 if (!access_ok(uc, sizeof(*uc)))
749 if (__get_user_sigset(&set, &uc->uc_sigmask))
751 set_current_blocked(&set);
753 if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM)) {
755 * If there is a transactional state then throw it away.
756 * The purpose of a sigreturn is to destroy all traces of the
757 * signal frame, this includes any transactional state created
758 * within in. We only check for suspended as we can never be
759 * active in the kernel, we are active, there is nothing better to
760 * do than go ahead and Bad Thing later.
761 * The cause is not important as there will never be a
762 * recheckpoint so it's not user visible.
764 if (MSR_TM_SUSPENDED(mfmsr()))
765 tm_reclaim_current(0);
768 * Disable MSR[TS] bit also, so, if there is an exception in the
769 * code below (as a page fault in copy_ckvsx_to_user()), it does
770 * not recheckpoint this task if there was a context switch inside
773 * A major page fault can indirectly call schedule(). A reschedule
774 * process in the middle of an exception can have a side effect
775 * (Changing the CPU MSR[TS] state), since schedule() is called
776 * with the CPU MSR[TS] disable and returns with MSR[TS]=Suspended
777 * (switch_to() calls tm_recheckpoint() for the 'new' process). In
778 * this case, the process continues to be the same in the CPU, but
779 * the CPU state just changed.
781 * This can cause a TM Bad Thing, since the MSR in the stack will
782 * have the MSR[TS]=0, and this is what will be used to RFID.
784 * Clearing MSR[TS] state here will avoid a recheckpoint if there
785 * is any process reschedule in kernel space. The MSR[TS] state
786 * does not need to be saved also, since it will be replaced with
787 * the MSR[TS] that came from user context later, at
788 * restore_tm_sigcontexts.
790 regs_set_return_msr(regs, regs->msr & ~MSR_TS_MASK);
792 if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR]))
796 if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM) && MSR_TM_ACTIVE(msr)) {
797 /* We recheckpoint on return. */
798 struct ucontext __user *uc_transact;
800 /* Trying to start TM on non TM system */
801 if (!cpu_has_feature(CPU_FTR_TM))
804 if (__get_user(uc_transact, &uc->uc_link))
806 if (restore_tm_sigcontexts(current, &uc->uc_mcontext,
807 &uc_transact->uc_mcontext))
811 * Fall through, for non-TM restore
813 * Unset MSR[TS] on the thread regs since MSR from user
814 * context does not have MSR active, and recheckpoint was
815 * not called since restore_tm_sigcontexts() was not called
818 * If not unsetting it, the code can RFID to userspace with
819 * MSR[TS] set, but without CPU in the proper state,
820 * causing a TM bad thing.
822 regs_set_return_msr(current->thread.regs,
823 current->thread.regs->msr & ~MSR_TS_MASK);
824 if (!user_read_access_begin(&uc->uc_mcontext, sizeof(uc->uc_mcontext)))
827 unsafe_restore_sigcontext(current, NULL, 1, &uc->uc_mcontext,
830 user_read_access_end();
833 if (restore_altstack(&uc->uc_stack))
836 set_thread_flag(TIF_RESTOREALL);
841 user_read_access_end();
843 signal_fault(current, regs, "rt_sigreturn", uc);
849 int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
850 struct task_struct *tsk)
852 struct rt_sigframe __user *frame;
853 unsigned long newsp = 0;
855 struct pt_regs *regs = tsk->thread.regs;
856 /* Save the thread's msr before get_tm_stackpointer() changes it */
857 unsigned long msr = regs->msr;
859 frame = get_sigframe(ksig, tsk, sizeof(*frame), 0);
862 * This only applies when calling unsafe_setup_sigcontext() and must be
863 * called before opening the uaccess window.
865 if (!MSR_TM_ACTIVE(msr))
866 prepare_setup_sigcontext(tsk);
868 if (!user_write_access_begin(frame, sizeof(*frame)))
871 unsafe_put_user(&frame->info, &frame->pinfo, badframe_block);
872 unsafe_put_user(&frame->uc, &frame->puc, badframe_block);
874 /* Create the ucontext. */
875 unsafe_put_user(0, &frame->uc.uc_flags, badframe_block);
876 unsafe_save_altstack(&frame->uc.uc_stack, regs->gpr[1], badframe_block);
878 if (MSR_TM_ACTIVE(msr)) {
879 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
880 /* The ucontext_t passed to userland points to the second
881 * ucontext_t (for transactional state) with its uc_link ptr.
883 unsafe_put_user(&frame->uc_transact, &frame->uc.uc_link, badframe_block);
885 user_write_access_end();
887 err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext,
888 &frame->uc_transact.uc_mcontext,
889 tsk, ksig->sig, NULL,
890 (unsigned long)ksig->ka.sa.sa_handler,
893 if (!user_write_access_begin(&frame->uc.uc_sigmask,
894 sizeof(frame->uc.uc_sigmask)))
899 unsafe_put_user(0, &frame->uc.uc_link, badframe_block);
900 unsafe_setup_sigcontext(&frame->uc.uc_mcontext, tsk, ksig->sig,
901 NULL, (unsigned long)ksig->ka.sa.sa_handler,
905 unsafe_copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set), badframe_block);
906 user_write_access_end();
908 /* Save the siginfo outside of the unsafe block. */
909 if (copy_siginfo_to_user(&frame->info, &ksig->info))
912 /* Make sure signal handler doesn't get spurious FP exceptions */
913 tsk->thread.fp_state.fpscr = 0;
915 /* Set up to return from userspace. */
916 if (tsk->mm->context.vdso) {
917 regs_set_return_ip(regs, VDSO64_SYMBOL(tsk->mm->context.vdso, sigtramp_rt64));
919 err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
922 regs_set_return_ip(regs, (unsigned long) &frame->tramp[0]);
925 /* Allocate a dummy caller frame for the signal handler. */
926 newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE;
927 err |= put_user(regs->gpr[1], (unsigned long __user *)newsp);
929 /* Set up "regs" so we "return" to the signal handler. */
930 if (is_elf2_task()) {
931 regs->ctr = (unsigned long) ksig->ka.sa.sa_handler;
932 regs->gpr[12] = regs->ctr;
934 /* Handler is *really* a pointer to the function descriptor for
935 * the signal routine. The first entry in the function
936 * descriptor is the entry address of signal and the second
937 * entry is the TOC value we need to use.
939 func_descr_t __user *funct_desc_ptr =
940 (func_descr_t __user *) ksig->ka.sa.sa_handler;
942 err |= get_user(regs->ctr, &funct_desc_ptr->entry);
943 err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
946 /* enter the signal handler in native-endian mode */
947 regs_set_return_msr(regs, (regs->msr & ~MSR_LE) | (MSR_KERNEL & MSR_LE));
948 regs->gpr[1] = newsp;
949 regs->gpr[3] = ksig->sig;
951 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
952 regs->gpr[4] = (unsigned long)&frame->info;
953 regs->gpr[5] = (unsigned long)&frame->uc;
954 regs->gpr[6] = (unsigned long) frame;
956 regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext;
964 user_write_access_end();
966 signal_fault(current, regs, "handle_rt_signal64", frame);