Back to home page

OSCL-LXR
 
 

     

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*  linux/arch/sparc/kernel/signal.c
0003  *
0004  *  Copyright (C) 1991, 1992  Linus Torvalds
0005  *  Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
0006  *  Copyright (C) 1996 Miguel de Icaza (miguel@nuclecu.unam.mx)
0007  *  Copyright (C) 1997 Eddie C. Dost   (ecd@skynet.be)
0008  */
0009 
0010 #include <linux/sched.h>
0011 #include <linux/kernel.h>
0012 #include <linux/signal.h>
0013 #include <linux/errno.h>
0014 #include <linux/wait.h>
0015 #include <linux/ptrace.h>
0016 #include <linux/unistd.h>
0017 #include <linux/mm.h>
0018 #include <linux/tty.h>
0019 #include <linux/smp.h>
0020 #include <linux/binfmts.h>  /* do_coredum */
0021 #include <linux/bitops.h>
0022 #include <linux/resume_user_mode.h>
0023 
0024 #include <linux/uaccess.h>
0025 #include <asm/ptrace.h>
0026 #include <asm/cacheflush.h> /* flush_sig_insns */
0027 #include <asm/switch_to.h>
0028 
0029 #include "sigutil.h"
0030 #include "kernel.h"
0031 
0032 extern void fpsave(unsigned long *fpregs, unsigned long *fsr,
0033            void *fpqueue, unsigned long *fpqdepth);
0034 extern void fpload(unsigned long *fpregs, unsigned long *fsr);
0035 
0036 struct signal_frame {
0037     struct sparc_stackf ss;
0038     __siginfo32_t       info;
0039     __siginfo_fpu_t __user  *fpu_save;
0040     unsigned long       insns[2] __attribute__ ((aligned (8)));
0041     unsigned int        extramask[_NSIG_WORDS - 1];
0042     unsigned int        extra_size; /* Should be 0 */
0043     __siginfo_rwin_t __user *rwin_save;
0044 } __attribute__((aligned(8)));
0045 
0046 struct rt_signal_frame {
0047     struct sparc_stackf ss;
0048     siginfo_t       info;
0049     struct pt_regs      regs;
0050     sigset_t        mask;
0051     __siginfo_fpu_t __user  *fpu_save;
0052     unsigned int        insns[2];
0053     stack_t         stack;
0054     unsigned int        extra_size; /* Should be 0 */
0055     __siginfo_rwin_t __user *rwin_save;
0056 } __attribute__((aligned(8)));
0057 
0058 /* Align macros */
0059 #define SF_ALIGNEDSZ  (((sizeof(struct signal_frame) + 7) & (~7)))
0060 #define RT_ALIGNEDSZ  (((sizeof(struct rt_signal_frame) + 7) & (~7)))
0061 
0062 /* Checks if the fp is valid.  We always build signal frames which are
0063  * 16-byte aligned, therefore we can always enforce that the restore
0064  * frame has that property as well.
0065  */
0066 static inline bool invalid_frame_pointer(void __user *fp, int fplen)
0067 {
0068     if ((((unsigned long) fp) & 15) || !access_ok(fp, fplen))
0069         return true;
0070 
0071     return false;
0072 }
0073 
0074 asmlinkage void do_sigreturn(struct pt_regs *regs)
0075 {
0076     unsigned long up_psr, pc, npc, ufp;
0077     struct signal_frame __user *sf;
0078     sigset_t set;
0079     __siginfo_fpu_t __user *fpu_save;
0080     __siginfo_rwin_t __user *rwin_save;
0081     int err;
0082 
0083     /* Always make any pending restarted system calls return -EINTR */
0084     current->restart_block.fn = do_no_restart_syscall;
0085 
0086     synchronize_user_stack();
0087 
0088     sf = (struct signal_frame __user *) regs->u_regs[UREG_FP];
0089 
0090     /* 1. Make sure we are not getting garbage from the user */
0091     if (invalid_frame_pointer(sf, sizeof(*sf)))
0092         goto segv_and_exit;
0093 
0094     if (get_user(ufp, &sf->info.si_regs.u_regs[UREG_FP]))
0095         goto segv_and_exit;
0096 
0097     if (ufp & 0x7)
0098         goto segv_and_exit;
0099 
0100     err = __get_user(pc,  &sf->info.si_regs.pc);
0101     err |= __get_user(npc, &sf->info.si_regs.npc);
0102 
0103     if ((pc | npc) & 3)
0104         goto segv_and_exit;
0105 
0106     /* 2. Restore the state */
0107     up_psr = regs->psr;
0108     err |= __copy_from_user(regs, &sf->info.si_regs, sizeof(struct pt_regs));
0109 
0110     /* User can only change condition codes and FPU enabling in %psr. */
0111     regs->psr = (up_psr & ~(PSR_ICC | PSR_EF))
0112           | (regs->psr & (PSR_ICC | PSR_EF));
0113 
0114     /* Prevent syscall restart.  */
0115     pt_regs_clear_syscall(regs);
0116 
0117     err |= __get_user(fpu_save, &sf->fpu_save);
0118     if (fpu_save)
0119         err |= restore_fpu_state(regs, fpu_save);
0120     err |= __get_user(rwin_save, &sf->rwin_save);
0121     if (rwin_save)
0122         err |= restore_rwin_state(rwin_save);
0123 
0124     /* This is pretty much atomic, no amount locking would prevent
0125      * the races which exist anyways.
0126      */
0127     err |= __get_user(set.sig[0], &sf->info.si_mask);
0128     err |= __copy_from_user(&set.sig[1], &sf->extramask,
0129                     (_NSIG_WORDS-1) * sizeof(unsigned int));
0130                
0131     if (err)
0132         goto segv_and_exit;
0133 
0134     set_current_blocked(&set);
0135     return;
0136 
0137 segv_and_exit:
0138     force_sig(SIGSEGV);
0139 }
0140 
0141 asmlinkage void do_rt_sigreturn(struct pt_regs *regs)
0142 {
0143     struct rt_signal_frame __user *sf;
0144     unsigned int psr, pc, npc, ufp;
0145     __siginfo_fpu_t __user *fpu_save;
0146     __siginfo_rwin_t __user *rwin_save;
0147     sigset_t set;
0148     int err;
0149 
0150     synchronize_user_stack();
0151     sf = (struct rt_signal_frame __user *) regs->u_regs[UREG_FP];
0152     if (invalid_frame_pointer(sf, sizeof(*sf)))
0153         goto segv;
0154 
0155     if (get_user(ufp, &sf->regs.u_regs[UREG_FP]))
0156         goto segv;
0157 
0158     if (ufp & 0x7)
0159         goto segv;
0160 
0161     err = __get_user(pc, &sf->regs.pc);
0162     err |= __get_user(npc, &sf->regs.npc);
0163     err |= ((pc | npc) & 0x03);
0164 
0165     err |= __get_user(regs->y, &sf->regs.y);
0166     err |= __get_user(psr, &sf->regs.psr);
0167 
0168     err |= __copy_from_user(&regs->u_regs[UREG_G1],
0169                 &sf->regs.u_regs[UREG_G1], 15 * sizeof(u32));
0170 
0171     regs->psr = (regs->psr & ~PSR_ICC) | (psr & PSR_ICC);
0172 
0173     /* Prevent syscall restart.  */
0174     pt_regs_clear_syscall(regs);
0175 
0176     err |= __get_user(fpu_save, &sf->fpu_save);
0177     if (!err && fpu_save)
0178         err |= restore_fpu_state(regs, fpu_save);
0179     err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t));
0180     err |= restore_altstack(&sf->stack);
0181     
0182     if (err)
0183         goto segv;
0184         
0185     regs->pc = pc;
0186     regs->npc = npc;
0187     
0188     err |= __get_user(rwin_save, &sf->rwin_save);
0189     if (!err && rwin_save) {
0190         if (restore_rwin_state(rwin_save))
0191             goto segv;
0192     }
0193 
0194     set_current_blocked(&set);
0195     return;
0196 segv:
0197     force_sig(SIGSEGV);
0198 }
0199 
0200 static inline void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize)
0201 {
0202     unsigned long sp = regs->u_regs[UREG_FP];
0203 
0204     /*
0205      * If we are on the alternate signal stack and would overflow it, don't.
0206      * Return an always-bogus address instead so we will die with SIGSEGV.
0207      */
0208     if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
0209         return (void __user *) -1L;
0210 
0211     /* This is the X/Open sanctioned signal stack switching.  */
0212     sp = sigsp(sp, ksig) - framesize;
0213 
0214     /* Always align the stack frame.  This handles two cases.  First,
0215      * sigaltstack need not be mindful of platform specific stack
0216      * alignment.  Second, if we took this signal because the stack
0217      * is not aligned properly, we'd like to take the signal cleanly
0218      * and report that.
0219      */
0220     sp &= ~15UL;
0221 
0222     return (void __user *) sp;
0223 }
0224 
0225 static int setup_frame(struct ksignal *ksig, struct pt_regs *regs,
0226                sigset_t *oldset)
0227 {
0228     struct signal_frame __user *sf;
0229     int sigframe_size, err, wsaved;
0230     void __user *tail;
0231 
0232     /* 1. Make sure everything is clean */
0233     synchronize_user_stack();
0234 
0235     wsaved = current_thread_info()->w_saved;
0236 
0237     sigframe_size = sizeof(*sf);
0238     if (used_math())
0239         sigframe_size += sizeof(__siginfo_fpu_t);
0240     if (wsaved)
0241         sigframe_size += sizeof(__siginfo_rwin_t);
0242 
0243     sf = (struct signal_frame __user *)
0244         get_sigframe(ksig, regs, sigframe_size);
0245 
0246     if (invalid_frame_pointer(sf, sigframe_size)) {
0247         force_exit_sig(SIGILL);
0248         return -EINVAL;
0249     }
0250 
0251     tail = sf + 1;
0252 
0253     /* 2. Save the current process state */
0254     err = __copy_to_user(&sf->info.si_regs, regs, sizeof(struct pt_regs));
0255     
0256     err |= __put_user(0, &sf->extra_size);
0257 
0258     if (used_math()) {
0259         __siginfo_fpu_t __user *fp = tail;
0260         tail += sizeof(*fp);
0261         err |= save_fpu_state(regs, fp);
0262         err |= __put_user(fp, &sf->fpu_save);
0263     } else {
0264         err |= __put_user(0, &sf->fpu_save);
0265     }
0266     if (wsaved) {
0267         __siginfo_rwin_t __user *rwp = tail;
0268         tail += sizeof(*rwp);
0269         err |= save_rwin_state(wsaved, rwp);
0270         err |= __put_user(rwp, &sf->rwin_save);
0271     } else {
0272         err |= __put_user(0, &sf->rwin_save);
0273     }
0274 
0275     err |= __put_user(oldset->sig[0], &sf->info.si_mask);
0276     err |= __copy_to_user(sf->extramask, &oldset->sig[1],
0277                   (_NSIG_WORDS - 1) * sizeof(unsigned int));
0278     if (!wsaved) {
0279         err |= __copy_to_user(sf, (char *) regs->u_regs[UREG_FP],
0280                       sizeof(struct reg_window32));
0281     } else {
0282         struct reg_window32 *rp;
0283 
0284         rp = &current_thread_info()->reg_window[wsaved - 1];
0285         err |= __copy_to_user(sf, rp, sizeof(struct reg_window32));
0286     }
0287     if (err)
0288         return err;
0289     
0290     /* 3. signal handler back-trampoline and parameters */
0291     regs->u_regs[UREG_FP] = (unsigned long) sf;
0292     regs->u_regs[UREG_I0] = ksig->sig;
0293     regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
0294     regs->u_regs[UREG_I2] = (unsigned long) &sf->info;
0295 
0296     /* 4. signal handler */
0297     regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
0298     regs->npc = (regs->pc + 4);
0299 
0300     /* 5. return to kernel instructions */
0301     if (ksig->ka.ka_restorer)
0302         regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer;
0303     else {
0304         regs->u_regs[UREG_I7] = (unsigned long)(&(sf->insns[0]) - 2);
0305 
0306         /* mov __NR_sigreturn, %g1 */
0307         err |= __put_user(0x821020d8, &sf->insns[0]);
0308 
0309         /* t 0x10 */
0310         err |= __put_user(0x91d02010, &sf->insns[1]);
0311         if (err)
0312             return err;
0313 
0314         /* Flush instruction space. */
0315         flush_sig_insns(current->mm, (unsigned long) &(sf->insns[0]));
0316     }
0317     return 0;
0318 }
0319 
0320 static int setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs,
0321               sigset_t *oldset)
0322 {
0323     struct rt_signal_frame __user *sf;
0324     int sigframe_size, wsaved;
0325     void __user *tail;
0326     unsigned int psr;
0327     int err;
0328 
0329     synchronize_user_stack();
0330     wsaved = current_thread_info()->w_saved;
0331     sigframe_size = sizeof(*sf);
0332     if (used_math())
0333         sigframe_size += sizeof(__siginfo_fpu_t);
0334     if (wsaved)
0335         sigframe_size += sizeof(__siginfo_rwin_t);
0336     sf = (struct rt_signal_frame __user *)
0337         get_sigframe(ksig, regs, sigframe_size);
0338     if (invalid_frame_pointer(sf, sigframe_size)) {
0339         force_exit_sig(SIGILL);
0340         return -EINVAL;
0341     }
0342 
0343     tail = sf + 1;
0344     err  = __put_user(regs->pc, &sf->regs.pc);
0345     err |= __put_user(regs->npc, &sf->regs.npc);
0346     err |= __put_user(regs->y, &sf->regs.y);
0347     psr = regs->psr;
0348     if (used_math())
0349         psr |= PSR_EF;
0350     err |= __put_user(psr, &sf->regs.psr);
0351     err |= __copy_to_user(&sf->regs.u_regs, regs->u_regs, sizeof(regs->u_regs));
0352     err |= __put_user(0, &sf->extra_size);
0353 
0354     if (psr & PSR_EF) {
0355         __siginfo_fpu_t __user *fp = tail;
0356         tail += sizeof(*fp);
0357         err |= save_fpu_state(regs, fp);
0358         err |= __put_user(fp, &sf->fpu_save);
0359     } else {
0360         err |= __put_user(0, &sf->fpu_save);
0361     }
0362     if (wsaved) {
0363         __siginfo_rwin_t __user *rwp = tail;
0364         tail += sizeof(*rwp);
0365         err |= save_rwin_state(wsaved, rwp);
0366         err |= __put_user(rwp, &sf->rwin_save);
0367     } else {
0368         err |= __put_user(0, &sf->rwin_save);
0369     }
0370     err |= __copy_to_user(&sf->mask, &oldset->sig[0], sizeof(sigset_t));
0371     
0372     /* Setup sigaltstack */
0373     err |= __save_altstack(&sf->stack, regs->u_regs[UREG_FP]);
0374     
0375     if (!wsaved) {
0376         err |= __copy_to_user(sf, (char *) regs->u_regs[UREG_FP],
0377                       sizeof(struct reg_window32));
0378     } else {
0379         struct reg_window32 *rp;
0380 
0381         rp = &current_thread_info()->reg_window[wsaved - 1];
0382         err |= __copy_to_user(sf, rp, sizeof(struct reg_window32));
0383     }
0384 
0385     err |= copy_siginfo_to_user(&sf->info, &ksig->info);
0386 
0387     if (err)
0388         return err;
0389 
0390     regs->u_regs[UREG_FP] = (unsigned long) sf;
0391     regs->u_regs[UREG_I0] = ksig->sig;
0392     regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
0393     regs->u_regs[UREG_I2] = (unsigned long) &sf->regs;
0394 
0395     regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
0396     regs->npc = (regs->pc + 4);
0397 
0398     if (ksig->ka.ka_restorer)
0399         regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer;
0400     else {
0401         regs->u_regs[UREG_I7] = (unsigned long)(&(sf->insns[0]) - 2);
0402 
0403         /* mov __NR_rt_sigreturn, %g1 */
0404         err |= __put_user(0x82102065, &sf->insns[0]);
0405 
0406         /* t 0x10 */
0407         err |= __put_user(0x91d02010, &sf->insns[1]);
0408         if (err)
0409             return err;
0410 
0411         /* Flush instruction space. */
0412         flush_sig_insns(current->mm, (unsigned long) &(sf->insns[0]));
0413     }
0414     return 0;
0415 }
0416 
0417 static inline void
0418 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
0419 {
0420     sigset_t *oldset = sigmask_to_save();
0421     int err;
0422 
0423     if (ksig->ka.sa.sa_flags & SA_SIGINFO)
0424         err = setup_rt_frame(ksig, regs, oldset);
0425     else
0426         err = setup_frame(ksig, regs, oldset);
0427     signal_setup_done(err, ksig, 0);
0428 }
0429 
0430 static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
0431                    struct sigaction *sa)
0432 {
0433     switch(regs->u_regs[UREG_I0]) {
0434     case ERESTART_RESTARTBLOCK:
0435     case ERESTARTNOHAND:
0436     no_system_call_restart:
0437         regs->u_regs[UREG_I0] = EINTR;
0438         regs->psr |= PSR_C;
0439         break;
0440     case ERESTARTSYS:
0441         if (!(sa->sa_flags & SA_RESTART))
0442             goto no_system_call_restart;
0443         fallthrough;
0444     case ERESTARTNOINTR:
0445         regs->u_regs[UREG_I0] = orig_i0;
0446         regs->pc -= 4;
0447         regs->npc -= 4;
0448     }
0449 }
0450 
0451 /* Note that 'init' is a special process: it doesn't get signals it doesn't
0452  * want to handle. Thus you cannot kill init even with a SIGKILL even by
0453  * mistake.
0454  */
0455 static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
0456 {
0457     struct ksignal ksig;
0458     int restart_syscall;
0459     bool has_handler;
0460 
0461     /* It's a lot of work and synchronization to add a new ptrace
0462      * register for GDB to save and restore in order to get
0463      * orig_i0 correct for syscall restarts when debugging.
0464      *
0465      * Although it should be the case that most of the global
0466      * registers are volatile across a system call, glibc already
0467      * depends upon that fact that we preserve them.  So we can't
0468      * just use any global register to save away the orig_i0 value.
0469      *
0470      * In particular %g2, %g3, %g4, and %g5 are all assumed to be
0471      * preserved across a system call trap by various pieces of
0472      * code in glibc.
0473      *
0474      * %g7 is used as the "thread register".   %g6 is not used in
0475      * any fixed manner.  %g6 is used as a scratch register and
0476      * a compiler temporary, but it's value is never used across
0477      * a system call.  Therefore %g6 is usable for orig_i0 storage.
0478      */
0479     if (pt_regs_is_syscall(regs) && (regs->psr & PSR_C))
0480         regs->u_regs[UREG_G6] = orig_i0;
0481 
0482     has_handler = get_signal(&ksig);
0483 
0484     /* If the debugger messes with the program counter, it clears
0485      * the software "in syscall" bit, directing us to not perform
0486      * a syscall restart.
0487      */
0488     restart_syscall = 0;
0489     if (pt_regs_is_syscall(regs) && (regs->psr & PSR_C)) {
0490         restart_syscall = 1;
0491         orig_i0 = regs->u_regs[UREG_G6];
0492     }
0493 
0494     if (has_handler) {
0495         if (restart_syscall)
0496             syscall_restart(orig_i0, regs, &ksig.ka.sa);
0497         handle_signal(&ksig, regs);
0498     } else {
0499         if (restart_syscall) {
0500             switch (regs->u_regs[UREG_I0]) {
0501             case ERESTARTNOHAND:
0502                 case ERESTARTSYS:
0503             case ERESTARTNOINTR:
0504                 /* replay the system call when we are done */
0505                 regs->u_regs[UREG_I0] = orig_i0;
0506                 regs->pc -= 4;
0507                 regs->npc -= 4;
0508                 pt_regs_clear_syscall(regs);
0509                 fallthrough;
0510             case ERESTART_RESTARTBLOCK:
0511                 regs->u_regs[UREG_G1] = __NR_restart_syscall;
0512                 regs->pc -= 4;
0513                 regs->npc -= 4;
0514                 pt_regs_clear_syscall(regs);
0515             }
0516         }
0517         restore_saved_sigmask();
0518     }
0519 }
0520 
0521 void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0,
0522               unsigned long thread_info_flags)
0523 {
0524     if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
0525         do_signal(regs, orig_i0);
0526     if (thread_info_flags & _TIF_NOTIFY_RESUME)
0527         resume_user_mode_work(regs);
0528 }
0529 
0530 asmlinkage int do_sys_sigstack(struct sigstack __user *ssptr,
0531                                struct sigstack __user *ossptr,
0532                                unsigned long sp)
0533 {
0534     int ret = -EFAULT;
0535 
0536     /* First see if old state is wanted. */
0537     if (ossptr) {
0538         if (put_user(current->sas_ss_sp + current->sas_ss_size,
0539                  &ossptr->the_stack) ||
0540             __put_user(on_sig_stack(sp), &ossptr->cur_status))
0541             goto out;
0542     }
0543 
0544     /* Now see if we want to update the new state. */
0545     if (ssptr) {
0546         char *ss_sp;
0547 
0548         if (get_user(ss_sp, &ssptr->the_stack))
0549             goto out;
0550         /* If the current stack was set with sigaltstack, don't
0551            swap stacks while we are on it.  */
0552         ret = -EPERM;
0553         if (current->sas_ss_sp && on_sig_stack(sp))
0554             goto out;
0555 
0556         /* Since we don't know the extent of the stack, and we don't
0557            track onstack-ness, but rather calculate it, we must
0558            presume a size.  Ho hum this interface is lossy.  */
0559         current->sas_ss_sp = (unsigned long)ss_sp - SIGSTKSZ;
0560         current->sas_ss_size = SIGSTKSZ;
0561     }
0562     ret = 0;
0563 out:
0564     return ret;
0565 }
[ Source navigation ] [ Diff markup ] [ Identifier search ] [ general search ]

This page was automatically generated by the 2.1.0 LXR engine.

The LXR team
Valid CSS 2.1! Valid HTML 4.01!