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TOMOYO Linux Cross Reference
Linux/arch/powerpc/kernel/signal_64.c

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  1 /*
  2  *  PowerPC version 
  3  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  4  *
  5  *  Derived from "arch/i386/kernel/signal.c"
  6  *    Copyright (C) 1991, 1992 Linus Torvalds
  7  *    1997-11-28  Modified for POSIX.1b signals by Richard Henderson
  8  *
  9  *  This program is free software; you can redistribute it and/or
 10  *  modify it under the terms of the GNU General Public License
 11  *  as published by the Free Software Foundation; either version
 12  *  2 of the License, or (at your option) any later version.
 13  */
 14 
 15 #include <linux/sched.h>
 16 #include <linux/mm.h>
 17 #include <linux/smp.h>
 18 #include <linux/kernel.h>
 19 #include <linux/signal.h>
 20 #include <linux/errno.h>
 21 #include <linux/wait.h>
 22 #include <linux/unistd.h>
 23 #include <linux/stddef.h>
 24 #include <linux/elf.h>
 25 #include <linux/ptrace.h>
 26 #include <linux/ratelimit.h>
 27 
 28 #include <asm/sigcontext.h>
 29 #include <asm/ucontext.h>
 30 #include <asm/uaccess.h>
 31 #include <asm/pgtable.h>
 32 #include <asm/unistd.h>
 33 #include <asm/cacheflush.h>
 34 #include <asm/syscalls.h>
 35 #include <asm/vdso.h>
 36 #include <asm/switch_to.h>
 37 #include <asm/tm.h>
 38 
 39 #include "signal.h"
 40 
 41 
 42 #define GP_REGS_SIZE    min(sizeof(elf_gregset_t), sizeof(struct pt_regs))
 43 #define FP_REGS_SIZE    sizeof(elf_fpregset_t)
 44 
 45 #define TRAMP_TRACEBACK 3
 46 #define TRAMP_SIZE      6
 47 
 48 /*
 49  * When we have signals to deliver, we set up on the user stack,
 50  * going down from the original stack pointer:
 51  *      1) a rt_sigframe struct which contains the ucontext     
 52  *      2) a gap of __SIGNAL_FRAMESIZE bytes which acts as a dummy caller
 53  *         frame for the signal handler.
 54  */
 55 
 56 struct rt_sigframe {
 57         /* sys_rt_sigreturn requires the ucontext be the first field */
 58         struct ucontext uc;
 59 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 60         struct ucontext uc_transact;
 61 #endif
 62         unsigned long _unused[2];
 63         unsigned int tramp[TRAMP_SIZE];
 64         struct siginfo __user *pinfo;
 65         void __user *puc;
 66         struct siginfo info;
 67         /* New 64 bit little-endian ABI allows redzone of 512 bytes below sp */
 68         char abigap[USER_REDZONE_SIZE];
 69 } __attribute__ ((aligned (16)));
 70 
 71 static const char fmt32[] = KERN_INFO \
 72         "%s[%d]: bad frame in %s: %08lx nip %08lx lr %08lx\n";
 73 static const char fmt64[] = KERN_INFO \
 74         "%s[%d]: bad frame in %s: %016lx nip %016lx lr %016lx\n";
 75 
 76 /*
 77  * This computes a quad word aligned pointer inside the vmx_reserve array
 78  * element. For historical reasons sigcontext might not be quad word aligned,
 79  * but the location we write the VMX regs to must be. See the comment in
 80  * sigcontext for more detail.
 81  */
 82 #ifdef CONFIG_ALTIVEC
 83 static elf_vrreg_t __user *sigcontext_vmx_regs(struct sigcontext __user *sc)
 84 {
 85         return (elf_vrreg_t __user *) (((unsigned long)sc->vmx_reserve + 15) & ~0xful);
 86 }
 87 #endif
 88 
 89 /*
 90  * Set up the sigcontext for the signal frame.
 91  */
 92 
 93 static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 94                  int signr, sigset_t *set, unsigned long handler,
 95                  int ctx_has_vsx_region)
 96 {
 97         /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
 98          * process never used altivec yet (MSR_VEC is zero in pt_regs of
 99          * the context). This is very important because we must ensure we
100          * don't lose the VRSAVE content that may have been set prior to
101          * the process doing its first vector operation
102          * Userland shall check AT_HWCAP to know whether it can rely on the
103          * v_regs pointer or not
104          */
105 #ifdef CONFIG_ALTIVEC
106         elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);
107         unsigned long vrsave;
108 #endif
109         unsigned long msr = regs->msr;
110         long err = 0;
111 
112 #ifdef CONFIG_ALTIVEC
113         err |= __put_user(v_regs, &sc->v_regs);
114 
115         /* save altivec registers */
116         if (current->thread.used_vr) {
117                 flush_altivec_to_thread(current);
118                 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */
119                 err |= __copy_to_user(v_regs, &current->thread.vr_state,
120                                       33 * sizeof(vector128));
121                 /* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg)
122                  * contains valid data.
123                  */
124                 msr |= MSR_VEC;
125         }
126         /* We always copy to/from vrsave, it's 0 if we don't have or don't
127          * use altivec.
128          */
129         vrsave = 0;
130         if (cpu_has_feature(CPU_FTR_ALTIVEC)) {
131                 vrsave = mfspr(SPRN_VRSAVE);
132                 current->thread.vrsave = vrsave;
133         }
134 
135         err |= __put_user(vrsave, (u32 __user *)&v_regs[33]);
136 #else /* CONFIG_ALTIVEC */
137         err |= __put_user(0, &sc->v_regs);
138 #endif /* CONFIG_ALTIVEC */
139         flush_fp_to_thread(current);
140         /* copy fpr regs and fpscr */
141         err |= copy_fpr_to_user(&sc->fp_regs, current);
142 
143         /*
144          * Clear the MSR VSX bit to indicate there is no valid state attached
145          * to this context, except in the specific case below where we set it.
146          */
147         msr &= ~MSR_VSX;
148 #ifdef CONFIG_VSX
149         /*
150          * Copy VSX low doubleword to local buffer for formatting,
151          * then out to userspace.  Update v_regs to point after the
152          * VMX data.
153          */
154         if (current->thread.used_vsr && ctx_has_vsx_region) {
155                 flush_vsx_to_thread(current);
156                 v_regs += ELF_NVRREG;
157                 err |= copy_vsx_to_user(v_regs, current);
158                 /* set MSR_VSX in the MSR value in the frame to
159                  * indicate that sc->vs_reg) contains valid data.
160                  */
161                 msr |= MSR_VSX;
162         }
163 #endif /* CONFIG_VSX */
164         err |= __put_user(&sc->gp_regs, &sc->regs);
165         WARN_ON(!FULL_REGS(regs));
166         err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE);
167         err |= __put_user(msr, &sc->gp_regs[PT_MSR]);
168         err |= __put_user(signr, &sc->signal);
169         err |= __put_user(handler, &sc->handler);
170         if (set != NULL)
171                 err |=  __put_user(set->sig[0], &sc->oldmask);
172 
173         return err;
174 }
175 
176 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
177 /*
178  * As above, but Transactional Memory is in use, so deliver sigcontexts
179  * containing checkpointed and transactional register states.
180  *
181  * To do this, we treclaim (done before entering here) to gather both sets of
182  * registers and set up the 'normal' sigcontext registers with rolled-back
183  * register values such that a simple signal handler sees a correct
184  * checkpointed register state.  If interested, a TM-aware sighandler can
185  * examine the transactional registers in the 2nd sigcontext to determine the
186  * real origin of the signal.
187  */
188 static long setup_tm_sigcontexts(struct sigcontext __user *sc,
189                                  struct sigcontext __user *tm_sc,
190                                  struct pt_regs *regs,
191                                  int signr, sigset_t *set, unsigned long handler)
192 {
193         /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
194          * process never used altivec yet (MSR_VEC is zero in pt_regs of
195          * the context). This is very important because we must ensure we
196          * don't lose the VRSAVE content that may have been set prior to
197          * the process doing its first vector operation
198          * Userland shall check AT_HWCAP to know wether it can rely on the
199          * v_regs pointer or not.
200          */
201 #ifdef CONFIG_ALTIVEC
202         elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);
203         elf_vrreg_t __user *tm_v_regs = sigcontext_vmx_regs(tm_sc);
204 #endif
205         unsigned long msr = regs->msr;
206         long err = 0;
207 
208         BUG_ON(!MSR_TM_ACTIVE(regs->msr));
209 
210         /* Remove TM bits from thread's MSR.  The MSR in the sigcontext
211          * just indicates to userland that we were doing a transaction, but we
212          * don't want to return in transactional state.  This also ensures
213          * that flush_fp_to_thread won't set TIF_RESTORE_TM again.
214          */
215         regs->msr &= ~MSR_TS_MASK;
216 
217         flush_fp_to_thread(current);
218 
219 #ifdef CONFIG_ALTIVEC
220         err |= __put_user(v_regs, &sc->v_regs);
221         err |= __put_user(tm_v_regs, &tm_sc->v_regs);
222 
223         /* save altivec registers */
224         if (current->thread.used_vr) {
225                 flush_altivec_to_thread(current);
226                 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */
227                 err |= __copy_to_user(v_regs, &current->thread.vr_state,
228                                       33 * sizeof(vector128));
229                 /* If VEC was enabled there are transactional VRs valid too,
230                  * else they're a copy of the checkpointed VRs.
231                  */
232                 if (msr & MSR_VEC)
233                         err |= __copy_to_user(tm_v_regs,
234                                               &current->thread.transact_vr,
235                                               33 * sizeof(vector128));
236                 else
237                         err |= __copy_to_user(tm_v_regs,
238                                               &current->thread.vr_state,
239                                               33 * sizeof(vector128));
240 
241                 /* set MSR_VEC in the MSR value in the frame to indicate
242                  * that sc->v_reg contains valid data.
243                  */
244                 msr |= MSR_VEC;
245         }
246         /* We always copy to/from vrsave, it's 0 if we don't have or don't
247          * use altivec.
248          */
249         if (cpu_has_feature(CPU_FTR_ALTIVEC))
250                 current->thread.vrsave = mfspr(SPRN_VRSAVE);
251         err |= __put_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
252         if (msr & MSR_VEC)
253                 err |= __put_user(current->thread.transact_vrsave,
254                                   (u32 __user *)&tm_v_regs[33]);
255         else
256                 err |= __put_user(current->thread.vrsave,
257                                   (u32 __user *)&tm_v_regs[33]);
258 
259 #else /* CONFIG_ALTIVEC */
260         err |= __put_user(0, &sc->v_regs);
261         err |= __put_user(0, &tm_sc->v_regs);
262 #endif /* CONFIG_ALTIVEC */
263 
264         /* copy fpr regs and fpscr */
265         err |= copy_fpr_to_user(&sc->fp_regs, current);
266         if (msr & MSR_FP)
267                 err |= copy_transact_fpr_to_user(&tm_sc->fp_regs, current);
268         else
269                 err |= copy_fpr_to_user(&tm_sc->fp_regs, current);
270 
271 #ifdef CONFIG_VSX
272         /*
273          * Copy VSX low doubleword to local buffer for formatting,
274          * then out to userspace.  Update v_regs to point after the
275          * VMX data.
276          */
277         if (current->thread.used_vsr) {
278                 flush_vsx_to_thread(current);
279                 v_regs += ELF_NVRREG;
280                 tm_v_regs += ELF_NVRREG;
281 
282                 err |= copy_vsx_to_user(v_regs, current);
283 
284                 if (msr & MSR_VSX)
285                         err |= copy_transact_vsx_to_user(tm_v_regs, current);
286                 else
287                         err |= copy_vsx_to_user(tm_v_regs, current);
288 
289                 /* set MSR_VSX in the MSR value in the frame to
290                  * indicate that sc->vs_reg) contains valid data.
291                  */
292                 msr |= MSR_VSX;
293         }
294 #endif /* CONFIG_VSX */
295 
296         err |= __put_user(&sc->gp_regs, &sc->regs);
297         err |= __put_user(&tm_sc->gp_regs, &tm_sc->regs);
298         WARN_ON(!FULL_REGS(regs));
299         err |= __copy_to_user(&tm_sc->gp_regs, regs, GP_REGS_SIZE);
300         err |= __copy_to_user(&sc->gp_regs,
301                               &current->thread.ckpt_regs, GP_REGS_SIZE);
302         err |= __put_user(msr, &tm_sc->gp_regs[PT_MSR]);
303         err |= __put_user(msr, &sc->gp_regs[PT_MSR]);
304         err |= __put_user(signr, &sc->signal);
305         err |= __put_user(handler, &sc->handler);
306         if (set != NULL)
307                 err |=  __put_user(set->sig[0], &sc->oldmask);
308 
309         return err;
310 }
311 #endif
312 
313 /*
314  * Restore the sigcontext from the signal frame.
315  */
316 
317 static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
318                               struct sigcontext __user *sc)
319 {
320 #ifdef CONFIG_ALTIVEC
321         elf_vrreg_t __user *v_regs;
322 #endif
323         unsigned long err = 0;
324         unsigned long save_r13 = 0;
325         unsigned long msr;
326 #ifdef CONFIG_VSX
327         int i;
328 #endif
329 
330         /* If this is not a signal return, we preserve the TLS in r13 */
331         if (!sig)
332                 save_r13 = regs->gpr[13];
333 
334         /* copy the GPRs */
335         err |= __copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr));
336         err |= __get_user(regs->nip, &sc->gp_regs[PT_NIP]);
337         /* get MSR separately, transfer the LE bit if doing signal return */
338         err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
339         if (sig)
340                 regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
341         err |= __get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3]);
342         err |= __get_user(regs->ctr, &sc->gp_regs[PT_CTR]);
343         err |= __get_user(regs->link, &sc->gp_regs[PT_LNK]);
344         err |= __get_user(regs->xer, &sc->gp_regs[PT_XER]);
345         err |= __get_user(regs->ccr, &sc->gp_regs[PT_CCR]);
346         /* skip SOFTE */
347         regs->trap = 0;
348         err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
349         err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
350         err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
351 
352         if (!sig)
353                 regs->gpr[13] = save_r13;
354         if (set != NULL)
355                 err |=  __get_user(set->sig[0], &sc->oldmask);
356 
357         /*
358          * Force reload of FP/VEC.
359          * This has to be done before copying stuff into current->thread.fpr/vr
360          * for the reasons explained in the previous comment.
361          */
362         regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
363 
364 #ifdef CONFIG_ALTIVEC
365         err |= __get_user(v_regs, &sc->v_regs);
366         if (err)
367                 return err;
368         if (v_regs && !access_ok(VERIFY_READ, v_regs, 34 * sizeof(vector128)))
369                 return -EFAULT;
370         /* Copy 33 vec registers (vr0..31 and vscr) from the stack */
371         if (v_regs != NULL && (msr & MSR_VEC) != 0)
372                 err |= __copy_from_user(&current->thread.vr_state, v_regs,
373                                         33 * sizeof(vector128));
374         else if (current->thread.used_vr)
375                 memset(&current->thread.vr_state, 0, 33 * sizeof(vector128));
376         /* Always get VRSAVE back */
377         if (v_regs != NULL)
378                 err |= __get_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
379         else
380                 current->thread.vrsave = 0;
381         if (cpu_has_feature(CPU_FTR_ALTIVEC))
382                 mtspr(SPRN_VRSAVE, current->thread.vrsave);
383 #endif /* CONFIG_ALTIVEC */
384         /* restore floating point */
385         err |= copy_fpr_from_user(current, &sc->fp_regs);
386 #ifdef CONFIG_VSX
387         /*
388          * Get additional VSX data. Update v_regs to point after the
389          * VMX data.  Copy VSX low doubleword from userspace to local
390          * buffer for formatting, then into the taskstruct.
391          */
392         v_regs += ELF_NVRREG;
393         if ((msr & MSR_VSX) != 0)
394                 err |= copy_vsx_from_user(current, v_regs);
395         else
396                 for (i = 0; i < 32 ; i++)
397                         current->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
398 #endif
399         return err;
400 }
401 
402 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
403 /*
404  * Restore the two sigcontexts from the frame of a transactional processes.
405  */
406 
407 static long restore_tm_sigcontexts(struct pt_regs *regs,
408                                    struct sigcontext __user *sc,
409                                    struct sigcontext __user *tm_sc)
410 {
411 #ifdef CONFIG_ALTIVEC
412         elf_vrreg_t __user *v_regs, *tm_v_regs;
413 #endif
414         unsigned long err = 0;
415         unsigned long msr;
416 #ifdef CONFIG_VSX
417         int i;
418 #endif
419         /* copy the GPRs */
420         err |= __copy_from_user(regs->gpr, tm_sc->gp_regs, sizeof(regs->gpr));
421         err |= __copy_from_user(&current->thread.ckpt_regs, sc->gp_regs,
422                                 sizeof(regs->gpr));
423 
424         /*
425          * TFHAR is restored from the checkpointed 'wound-back' ucontext's NIP.
426          * TEXASR was set by the signal delivery reclaim, as was TFIAR.
427          * Users doing anything abhorrent like thread-switching w/ signals for
428          * TM-Suspended code will have to back TEXASR/TFIAR up themselves.
429          * For the case of getting a signal and simply returning from it,
430          * we don't need to re-copy them here.
431          */
432         err |= __get_user(regs->nip, &tm_sc->gp_regs[PT_NIP]);
433         err |= __get_user(current->thread.tm_tfhar, &sc->gp_regs[PT_NIP]);
434 
435         /* get MSR separately, transfer the LE bit if doing signal return */
436         err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
437         /* Don't allow reserved mode. */
438         if (MSR_TM_RESV(msr))
439                 return -EINVAL;
440 
441         /* pull in MSR TM from user context */
442         regs->msr = (regs->msr & ~MSR_TS_MASK) | (msr & MSR_TS_MASK);
443 
444         /* pull in MSR LE from user context */
445         regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
446 
447         /* The following non-GPR non-FPR non-VR state is also checkpointed: */
448         err |= __get_user(regs->ctr, &tm_sc->gp_regs[PT_CTR]);
449         err |= __get_user(regs->link, &tm_sc->gp_regs[PT_LNK]);
450         err |= __get_user(regs->xer, &tm_sc->gp_regs[PT_XER]);
451         err |= __get_user(regs->ccr, &tm_sc->gp_regs[PT_CCR]);
452         err |= __get_user(current->thread.ckpt_regs.ctr,
453                           &sc->gp_regs[PT_CTR]);
454         err |= __get_user(current->thread.ckpt_regs.link,
455                           &sc->gp_regs[PT_LNK]);
456         err |= __get_user(current->thread.ckpt_regs.xer,
457                           &sc->gp_regs[PT_XER]);
458         err |= __get_user(current->thread.ckpt_regs.ccr,
459                           &sc->gp_regs[PT_CCR]);
460 
461         /* These regs are not checkpointed; they can go in 'regs'. */
462         err |= __get_user(regs->trap, &sc->gp_regs[PT_TRAP]);
463         err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
464         err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
465         err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
466 
467         /*
468          * Force reload of FP/VEC.
469          * This has to be done before copying stuff into current->thread.fpr/vr
470          * for the reasons explained in the previous comment.
471          */
472         regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
473 
474 #ifdef CONFIG_ALTIVEC
475         err |= __get_user(v_regs, &sc->v_regs);
476         err |= __get_user(tm_v_regs, &tm_sc->v_regs);
477         if (err)
478                 return err;
479         if (v_regs && !access_ok(VERIFY_READ, v_regs, 34 * sizeof(vector128)))
480                 return -EFAULT;
481         if (tm_v_regs && !access_ok(VERIFY_READ,
482                                     tm_v_regs, 34 * sizeof(vector128)))
483                 return -EFAULT;
484         /* Copy 33 vec registers (vr0..31 and vscr) from the stack */
485         if (v_regs != NULL && tm_v_regs != NULL && (msr & MSR_VEC) != 0) {
486                 err |= __copy_from_user(&current->thread.vr_state, v_regs,
487                                         33 * sizeof(vector128));
488                 err |= __copy_from_user(&current->thread.transact_vr, tm_v_regs,
489                                         33 * sizeof(vector128));
490         }
491         else if (current->thread.used_vr) {
492                 memset(&current->thread.vr_state, 0, 33 * sizeof(vector128));
493                 memset(&current->thread.transact_vr, 0, 33 * sizeof(vector128));
494         }
495         /* Always get VRSAVE back */
496         if (v_regs != NULL && tm_v_regs != NULL) {
497                 err |= __get_user(current->thread.vrsave,
498                                   (u32 __user *)&v_regs[33]);
499                 err |= __get_user(current->thread.transact_vrsave,
500                                   (u32 __user *)&tm_v_regs[33]);
501         }
502         else {
503                 current->thread.vrsave = 0;
504                 current->thread.transact_vrsave = 0;
505         }
506         if (cpu_has_feature(CPU_FTR_ALTIVEC))
507                 mtspr(SPRN_VRSAVE, current->thread.vrsave);
508 #endif /* CONFIG_ALTIVEC */
509         /* restore floating point */
510         err |= copy_fpr_from_user(current, &sc->fp_regs);
511         err |= copy_transact_fpr_from_user(current, &tm_sc->fp_regs);
512 #ifdef CONFIG_VSX
513         /*
514          * Get additional VSX data. Update v_regs to point after the
515          * VMX data.  Copy VSX low doubleword from userspace to local
516          * buffer for formatting, then into the taskstruct.
517          */
518         if (v_regs && ((msr & MSR_VSX) != 0)) {
519                 v_regs += ELF_NVRREG;
520                 tm_v_regs += ELF_NVRREG;
521                 err |= copy_vsx_from_user(current, v_regs);
522                 err |= copy_transact_vsx_from_user(current, tm_v_regs);
523         } else {
524                 for (i = 0; i < 32 ; i++) {
525                         current->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
526                         current->thread.transact_fp.fpr[i][TS_VSRLOWOFFSET] = 0;
527                 }
528         }
529 #endif
530         tm_enable();
531         /* Make sure the transaction is marked as failed */
532         current->thread.tm_texasr |= TEXASR_FS;
533         /* This loads the checkpointed FP/VEC state, if used */
534         tm_recheckpoint(&current->thread, msr);
535 
536         /* This loads the speculative FP/VEC state, if used */
537         if (msr & MSR_FP) {
538                 do_load_up_transact_fpu(&current->thread);
539                 regs->msr |= (MSR_FP | current->thread.fpexc_mode);
540         }
541 #ifdef CONFIG_ALTIVEC
542         if (msr & MSR_VEC) {
543                 do_load_up_transact_altivec(&current->thread);
544                 regs->msr |= MSR_VEC;
545         }
546 #endif
547 
548         return err;
549 }
550 #endif
551 
552 /*
553  * Setup the trampoline code on the stack
554  */
555 static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
556 {
557         int i;
558         long err = 0;
559 
560         /* addi r1, r1, __SIGNAL_FRAMESIZE  # Pop the dummy stackframe */
561         err |= __put_user(0x38210000UL | (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]);
562         /* li r0, __NR_[rt_]sigreturn| */
563         err |= __put_user(0x38000000UL | (syscall & 0xffff), &tramp[1]);
564         /* sc */
565         err |= __put_user(0x44000002UL, &tramp[2]);
566 
567         /* Minimal traceback info */
568         for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)
569                 err |= __put_user(0, &tramp[i]);
570 
571         if (!err)
572                 flush_icache_range((unsigned long) &tramp[0],
573                            (unsigned long) &tramp[TRAMP_SIZE]);
574 
575         return err;
576 }
577 
578 /*
579  * Userspace code may pass a ucontext which doesn't include VSX added
580  * at the end.  We need to check for this case.
581  */
582 #define UCONTEXTSIZEWITHOUTVSX \
583                 (sizeof(struct ucontext) - 32*sizeof(long))
584 
585 /*
586  * Handle {get,set,swap}_context operations
587  */
588 int sys_swapcontext(struct ucontext __user *old_ctx,
589                     struct ucontext __user *new_ctx,
590                     long ctx_size, long r6, long r7, long r8, struct pt_regs *regs)
591 {
592         unsigned char tmp;
593         sigset_t set;
594         unsigned long new_msr = 0;
595         int ctx_has_vsx_region = 0;
596 
597         if (new_ctx &&
598             get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR]))
599                 return -EFAULT;
600         /*
601          * Check that the context is not smaller than the original
602          * size (with VMX but without VSX)
603          */
604         if (ctx_size < UCONTEXTSIZEWITHOUTVSX)
605                 return -EINVAL;
606         /*
607          * If the new context state sets the MSR VSX bits but
608          * it doesn't provide VSX state.
609          */
610         if ((ctx_size < sizeof(struct ucontext)) &&
611             (new_msr & MSR_VSX))
612                 return -EINVAL;
613         /* Does the context have enough room to store VSX data? */
614         if (ctx_size >= sizeof(struct ucontext))
615                 ctx_has_vsx_region = 1;
616 
617         if (old_ctx != NULL) {
618                 if (!access_ok(VERIFY_WRITE, old_ctx, ctx_size)
619                     || setup_sigcontext(&old_ctx->uc_mcontext, regs, 0, NULL, 0,
620                                         ctx_has_vsx_region)
621                     || __copy_to_user(&old_ctx->uc_sigmask,
622                                       &current->blocked, sizeof(sigset_t)))
623                         return -EFAULT;
624         }
625         if (new_ctx == NULL)
626                 return 0;
627         if (!access_ok(VERIFY_READ, new_ctx, ctx_size)
628             || __get_user(tmp, (u8 __user *) new_ctx)
629             || __get_user(tmp, (u8 __user *) new_ctx + ctx_size - 1))
630                 return -EFAULT;
631 
632         /*
633          * If we get a fault copying the context into the kernel's
634          * image of the user's registers, we can't just return -EFAULT
635          * because the user's registers will be corrupted.  For instance
636          * the NIP value may have been updated but not some of the
637          * other registers.  Given that we have done the access_ok
638          * and successfully read the first and last bytes of the region
639          * above, this should only happen in an out-of-memory situation
640          * or if another thread unmaps the region containing the context.
641          * We kill the task with a SIGSEGV in this situation.
642          */
643 
644         if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set)))
645                 do_exit(SIGSEGV);
646         set_current_blocked(&set);
647         if (restore_sigcontext(regs, NULL, 0, &new_ctx->uc_mcontext))
648                 do_exit(SIGSEGV);
649 
650         /* This returns like rt_sigreturn */
651         set_thread_flag(TIF_RESTOREALL);
652         return 0;
653 }
654 
655 
656 /*
657  * Do a signal return; undo the signal stack.
658  */
659 
660 int sys_rt_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5,
661                      unsigned long r6, unsigned long r7, unsigned long r8,
662                      struct pt_regs *regs)
663 {
664         struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
665         sigset_t set;
666 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
667         unsigned long msr;
668 #endif
669 
670         /* Always make any pending restarted system calls return -EINTR */
671         current->restart_block.fn = do_no_restart_syscall;
672 
673         if (!access_ok(VERIFY_READ, uc, sizeof(*uc)))
674                 goto badframe;
675 
676         if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
677                 goto badframe;
678         set_current_blocked(&set);
679 
680 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
681         /*
682          * If there is a transactional state then throw it away.
683          * The purpose of a sigreturn is to destroy all traces of the
684          * signal frame, this includes any transactional state created
685          * within in. We only check for suspended as we can never be
686          * active in the kernel, we are active, there is nothing better to
687          * do than go ahead and Bad Thing later.
688          * The cause is not important as there will never be a
689          * recheckpoint so it's not user visible.
690          */
691         if (MSR_TM_SUSPENDED(mfmsr()))
692                 tm_reclaim_current(0);
693 
694         if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR]))
695                 goto badframe;
696         if (MSR_TM_ACTIVE(msr)) {
697                 /* We recheckpoint on return. */
698                 struct ucontext __user *uc_transact;
699                 if (__get_user(uc_transact, &uc->uc_link))
700                         goto badframe;
701                 if (restore_tm_sigcontexts(regs, &uc->uc_mcontext,
702                                            &uc_transact->uc_mcontext))
703                         goto badframe;
704         }
705         else
706         /* Fall through, for non-TM restore */
707 #endif
708         if (restore_sigcontext(regs, NULL, 1, &uc->uc_mcontext))
709                 goto badframe;
710 
711         if (restore_altstack(&uc->uc_stack))
712                 goto badframe;
713 
714         set_thread_flag(TIF_RESTOREALL);
715         return 0;
716 
717 badframe:
718         if (show_unhandled_signals)
719                 printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
720                                    current->comm, current->pid, "rt_sigreturn",
721                                    (long)uc, regs->nip, regs->link);
722 
723         force_sig(SIGSEGV, current);
724         return 0;
725 }
726 
727 int handle_rt_signal64(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
728 {
729         struct rt_sigframe __user *frame;
730         unsigned long newsp = 0;
731         long err = 0;
732 
733         frame = get_sigframe(ksig, get_tm_stackpointer(regs), sizeof(*frame), 0);
734         if (unlikely(frame == NULL))
735                 goto badframe;
736 
737         err |= __put_user(&frame->info, &frame->pinfo);
738         err |= __put_user(&frame->uc, &frame->puc);
739         err |= copy_siginfo_to_user(&frame->info, &ksig->info);
740         if (err)
741                 goto badframe;
742 
743         /* Create the ucontext.  */
744         err |= __put_user(0, &frame->uc.uc_flags);
745         err |= __save_altstack(&frame->uc.uc_stack, regs->gpr[1]);
746 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
747         if (MSR_TM_ACTIVE(regs->msr)) {
748                 /* The ucontext_t passed to userland points to the second
749                  * ucontext_t (for transactional state) with its uc_link ptr.
750                  */
751                 err |= __put_user(&frame->uc_transact, &frame->uc.uc_link);
752                 err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext,
753                                             &frame->uc_transact.uc_mcontext,
754                                             regs, ksig->sig,
755                                             NULL,
756                                             (unsigned long)ksig->ka.sa.sa_handler);
757         } else
758 #endif
759         {
760                 err |= __put_user(0, &frame->uc.uc_link);
761                 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, ksig->sig,
762                                         NULL, (unsigned long)ksig->ka.sa.sa_handler,
763                                         1);
764         }
765         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
766         if (err)
767                 goto badframe;
768 
769         /* Make sure signal handler doesn't get spurious FP exceptions */
770         current->thread.fp_state.fpscr = 0;
771 
772         /* Set up to return from userspace. */
773         if (vdso64_rt_sigtramp && current->mm->context.vdso_base) {
774                 regs->link = current->mm->context.vdso_base + vdso64_rt_sigtramp;
775         } else {
776                 err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
777                 if (err)
778                         goto badframe;
779                 regs->link = (unsigned long) &frame->tramp[0];
780         }
781 
782         /* Allocate a dummy caller frame for the signal handler. */
783         newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE;
784         err |= put_user(regs->gpr[1], (unsigned long __user *)newsp);
785 
786         /* Set up "regs" so we "return" to the signal handler. */
787         if (is_elf2_task()) {
788                 regs->nip = (unsigned long) ksig->ka.sa.sa_handler;
789                 regs->gpr[12] = regs->nip;
790         } else {
791                 /* Handler is *really* a pointer to the function descriptor for
792                  * the signal routine.  The first entry in the function
793                  * descriptor is the entry address of signal and the second
794                  * entry is the TOC value we need to use.
795                  */
796                 func_descr_t __user *funct_desc_ptr =
797                         (func_descr_t __user *) ksig->ka.sa.sa_handler;
798 
799                 err |= get_user(regs->nip, &funct_desc_ptr->entry);
800                 err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
801         }
802 
803         /* enter the signal handler in native-endian mode */
804         regs->msr &= ~MSR_LE;
805         regs->msr |= (MSR_KERNEL & MSR_LE);
806         regs->gpr[1] = newsp;
807         regs->gpr[3] = ksig->sig;
808         regs->result = 0;
809         if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
810                 err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo);
811                 err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc);
812                 regs->gpr[6] = (unsigned long) frame;
813         } else {
814                 regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext;
815         }
816         if (err)
817                 goto badframe;
818 
819         return 0;
820 
821 badframe:
822         if (show_unhandled_signals)
823                 printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
824                                    current->comm, current->pid, "setup_rt_frame",
825                                    (long)frame, regs->nip, regs->link);
826 
827         return 1;
828 }
829 

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