123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496 |
- /*
- * Architecture-specific signal handling support.
- *
- * Copyright (C) 1999-2004 Hewlett-Packard Co
- * David Mosberger-Tang <davidm@hpl.hp.com>
- *
- * Derived from i386 and Alpha versions.
- */
- #include <linux/errno.h>
- #include <linux/kernel.h>
- #include <linux/mm.h>
- #include <linux/ptrace.h>
- #include <linux/tracehook.h>
- #include <linux/sched.h>
- #include <linux/signal.h>
- #include <linux/smp.h>
- #include <linux/stddef.h>
- #include <linux/tty.h>
- #include <linux/binfmts.h>
- #include <linux/unistd.h>
- #include <linux/wait.h>
- #include <asm/intrinsics.h>
- #include <asm/uaccess.h>
- #include <asm/rse.h>
- #include <asm/sigcontext.h>
- #include "sigframe.h"
- #define DEBUG_SIG 0
- #define STACK_ALIGN 16 /* minimal alignment for stack pointer */
- #if _NSIG_WORDS > 1
- # define PUT_SIGSET(k,u) __copy_to_user((u)->sig, (k)->sig, sizeof(sigset_t))
- # define GET_SIGSET(k,u) __copy_from_user((k)->sig, (u)->sig, sizeof(sigset_t))
- #else
- # define PUT_SIGSET(k,u) __put_user((k)->sig[0], &(u)->sig[0])
- # define GET_SIGSET(k,u) __get_user((k)->sig[0], &(u)->sig[0])
- #endif
- static long
- restore_sigcontext (struct sigcontext __user *sc, struct sigscratch *scr)
- {
- unsigned long ip, flags, nat, um, cfm, rsc;
- long err;
- /* Always make any pending restarted system calls return -EINTR */
- current->restart_block.fn = do_no_restart_syscall;
- /* restore scratch that always needs gets updated during signal delivery: */
- err = __get_user(flags, &sc->sc_flags);
- err |= __get_user(nat, &sc->sc_nat);
- err |= __get_user(ip, &sc->sc_ip); /* instruction pointer */
- err |= __get_user(cfm, &sc->sc_cfm);
- err |= __get_user(um, &sc->sc_um); /* user mask */
- err |= __get_user(rsc, &sc->sc_ar_rsc);
- err |= __get_user(scr->pt.ar_unat, &sc->sc_ar_unat);
- err |= __get_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr);
- err |= __get_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
- err |= __get_user(scr->pt.pr, &sc->sc_pr); /* predicates */
- err |= __get_user(scr->pt.b0, &sc->sc_br[0]); /* b0 (rp) */
- err |= __get_user(scr->pt.b6, &sc->sc_br[6]); /* b6 */
- err |= __copy_from_user(&scr->pt.r1, &sc->sc_gr[1], 8); /* r1 */
- err |= __copy_from_user(&scr->pt.r8, &sc->sc_gr[8], 4*8); /* r8-r11 */
- err |= __copy_from_user(&scr->pt.r12, &sc->sc_gr[12], 2*8); /* r12-r13 */
- err |= __copy_from_user(&scr->pt.r15, &sc->sc_gr[15], 8); /* r15 */
- scr->pt.cr_ifs = cfm | (1UL << 63);
- scr->pt.ar_rsc = rsc | (3 << 2); /* force PL3 */
- /* establish new instruction pointer: */
- scr->pt.cr_iip = ip & ~0x3UL;
- ia64_psr(&scr->pt)->ri = ip & 0x3;
- scr->pt.cr_ipsr = (scr->pt.cr_ipsr & ~IA64_PSR_UM) | (um & IA64_PSR_UM);
- scr->scratch_unat = ia64_put_scratch_nat_bits(&scr->pt, nat);
- if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) {
- /* Restore most scratch-state only when not in syscall. */
- err |= __get_user(scr->pt.ar_ccv, &sc->sc_ar_ccv); /* ar.ccv */
- err |= __get_user(scr->pt.b7, &sc->sc_br[7]); /* b7 */
- err |= __get_user(scr->pt.r14, &sc->sc_gr[14]); /* r14 */
- err |= __copy_from_user(&scr->pt.ar_csd, &sc->sc_ar25, 2*8); /* ar.csd & ar.ssd */
- err |= __copy_from_user(&scr->pt.r2, &sc->sc_gr[2], 2*8); /* r2-r3 */
- err |= __copy_from_user(&scr->pt.r16, &sc->sc_gr[16], 16*8); /* r16-r31 */
- }
- if ((flags & IA64_SC_FLAG_FPH_VALID) != 0) {
- struct ia64_psr *psr = ia64_psr(&scr->pt);
- err |= __copy_from_user(current->thread.fph, &sc->sc_fr[32], 96*16);
- psr->mfh = 0; /* drop signal handler's fph contents... */
- preempt_disable();
- if (psr->dfh)
- ia64_drop_fpu(current);
- else {
- /* We already own the local fph, otherwise psr->dfh wouldn't be 0. */
- __ia64_load_fpu(current->thread.fph);
- ia64_set_local_fpu_owner(current);
- }
- preempt_enable();
- }
- return err;
- }
- int
- copy_siginfo_to_user (siginfo_t __user *to, const siginfo_t *from)
- {
- if (!access_ok(VERIFY_WRITE, to, sizeof(siginfo_t)))
- return -EFAULT;
- if (from->si_code < 0) {
- if (__copy_to_user(to, from, sizeof(siginfo_t)))
- return -EFAULT;
- return 0;
- } else {
- int err;
- /*
- * If you change siginfo_t structure, please be sure this code is fixed
- * accordingly. It should never copy any pad contained in the structure
- * to avoid security leaks, but must copy the generic 3 ints plus the
- * relevant union member.
- */
- err = __put_user(from->si_signo, &to->si_signo);
- err |= __put_user(from->si_errno, &to->si_errno);
- err |= __put_user((short)from->si_code, &to->si_code);
- switch (from->si_code >> 16) {
- case __SI_FAULT >> 16:
- err |= __put_user(from->si_flags, &to->si_flags);
- err |= __put_user(from->si_isr, &to->si_isr);
- case __SI_POLL >> 16:
- err |= __put_user(from->si_addr, &to->si_addr);
- err |= __put_user(from->si_imm, &to->si_imm);
- break;
- case __SI_TIMER >> 16:
- err |= __put_user(from->si_tid, &to->si_tid);
- err |= __put_user(from->si_overrun, &to->si_overrun);
- err |= __put_user(from->si_ptr, &to->si_ptr);
- break;
- case __SI_RT >> 16: /* Not generated by the kernel as of now. */
- case __SI_MESGQ >> 16:
- err |= __put_user(from->si_uid, &to->si_uid);
- err |= __put_user(from->si_pid, &to->si_pid);
- err |= __put_user(from->si_ptr, &to->si_ptr);
- break;
- case __SI_CHLD >> 16:
- err |= __put_user(from->si_utime, &to->si_utime);
- err |= __put_user(from->si_stime, &to->si_stime);
- err |= __put_user(from->si_status, &to->si_status);
- default:
- err |= __put_user(from->si_uid, &to->si_uid);
- err |= __put_user(from->si_pid, &to->si_pid);
- break;
- }
- return err;
- }
- }
- long
- ia64_rt_sigreturn (struct sigscratch *scr)
- {
- extern char ia64_strace_leave_kernel, ia64_leave_kernel;
- struct sigcontext __user *sc;
- struct siginfo si;
- sigset_t set;
- long retval;
- sc = &((struct sigframe __user *) (scr->pt.r12 + 16))->sc;
- /*
- * When we return to the previously executing context, r8 and r10 have already
- * been setup the way we want them. Indeed, if the signal wasn't delivered while
- * in a system call, we must not touch r8 or r10 as otherwise user-level state
- * could be corrupted.
- */
- retval = (long) &ia64_leave_kernel;
- if (test_thread_flag(TIF_SYSCALL_TRACE)
- || test_thread_flag(TIF_SYSCALL_AUDIT))
- /*
- * strace expects to be notified after sigreturn returns even though the
- * context to which we return may not be in the middle of a syscall.
- * Thus, the return-value that strace displays for sigreturn is
- * meaningless.
- */
- retval = (long) &ia64_strace_leave_kernel;
- if (!access_ok(VERIFY_READ, sc, sizeof(*sc)))
- goto give_sigsegv;
- if (GET_SIGSET(&set, &sc->sc_mask))
- goto give_sigsegv;
- set_current_blocked(&set);
- if (restore_sigcontext(sc, scr))
- goto give_sigsegv;
- #if DEBUG_SIG
- printk("SIG return (%s:%d): sp=%lx ip=%lx\n",
- current->comm, current->pid, scr->pt.r12, scr->pt.cr_iip);
- #endif
- if (restore_altstack(&sc->sc_stack))
- goto give_sigsegv;
- return retval;
- give_sigsegv:
- si.si_signo = SIGSEGV;
- si.si_errno = 0;
- si.si_code = SI_KERNEL;
- si.si_pid = task_pid_vnr(current);
- si.si_uid = from_kuid_munged(current_user_ns(), current_uid());
- si.si_addr = sc;
- force_sig_info(SIGSEGV, &si, current);
- return retval;
- }
- /*
- * This does just the minimum required setup of sigcontext.
- * Specifically, it only installs data that is either not knowable at
- * the user-level or that gets modified before execution in the
- * trampoline starts. Everything else is done at the user-level.
- */
- static long
- setup_sigcontext (struct sigcontext __user *sc, sigset_t *mask, struct sigscratch *scr)
- {
- unsigned long flags = 0, ifs, cfm, nat;
- long err = 0;
- ifs = scr->pt.cr_ifs;
- if (on_sig_stack((unsigned long) sc))
- flags |= IA64_SC_FLAG_ONSTACK;
- if ((ifs & (1UL << 63)) == 0)
- /* if cr_ifs doesn't have the valid bit set, we got here through a syscall */
- flags |= IA64_SC_FLAG_IN_SYSCALL;
- cfm = ifs & ((1UL << 38) - 1);
- ia64_flush_fph(current);
- if ((current->thread.flags & IA64_THREAD_FPH_VALID)) {
- flags |= IA64_SC_FLAG_FPH_VALID;
- err = __copy_to_user(&sc->sc_fr[32], current->thread.fph, 96*16);
- }
- nat = ia64_get_scratch_nat_bits(&scr->pt, scr->scratch_unat);
- err |= __put_user(flags, &sc->sc_flags);
- err |= __put_user(nat, &sc->sc_nat);
- err |= PUT_SIGSET(mask, &sc->sc_mask);
- err |= __put_user(cfm, &sc->sc_cfm);
- err |= __put_user(scr->pt.cr_ipsr & IA64_PSR_UM, &sc->sc_um);
- err |= __put_user(scr->pt.ar_rsc, &sc->sc_ar_rsc);
- err |= __put_user(scr->pt.ar_unat, &sc->sc_ar_unat); /* ar.unat */
- err |= __put_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr); /* ar.fpsr */
- err |= __put_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
- err |= __put_user(scr->pt.pr, &sc->sc_pr); /* predicates */
- err |= __put_user(scr->pt.b0, &sc->sc_br[0]); /* b0 (rp) */
- err |= __put_user(scr->pt.b6, &sc->sc_br[6]); /* b6 */
- err |= __copy_to_user(&sc->sc_gr[1], &scr->pt.r1, 8); /* r1 */
- err |= __copy_to_user(&sc->sc_gr[8], &scr->pt.r8, 4*8); /* r8-r11 */
- err |= __copy_to_user(&sc->sc_gr[12], &scr->pt.r12, 2*8); /* r12-r13 */
- err |= __copy_to_user(&sc->sc_gr[15], &scr->pt.r15, 8); /* r15 */
- err |= __put_user(scr->pt.cr_iip + ia64_psr(&scr->pt)->ri, &sc->sc_ip);
- if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) {
- /* Copy scratch regs to sigcontext if the signal didn't interrupt a syscall. */
- err |= __put_user(scr->pt.ar_ccv, &sc->sc_ar_ccv); /* ar.ccv */
- err |= __put_user(scr->pt.b7, &sc->sc_br[7]); /* b7 */
- err |= __put_user(scr->pt.r14, &sc->sc_gr[14]); /* r14 */
- err |= __copy_to_user(&sc->sc_ar25, &scr->pt.ar_csd, 2*8); /* ar.csd & ar.ssd */
- err |= __copy_to_user(&sc->sc_gr[2], &scr->pt.r2, 2*8); /* r2-r3 */
- err |= __copy_to_user(&sc->sc_gr[16], &scr->pt.r16, 16*8); /* r16-r31 */
- }
- return err;
- }
- /*
- * Check whether the register-backing store is already on the signal stack.
- */
- static inline int
- rbs_on_sig_stack (unsigned long bsp)
- {
- return (bsp - current->sas_ss_sp < current->sas_ss_size);
- }
- static long
- force_sigsegv_info (int sig, void __user *addr)
- {
- unsigned long flags;
- struct siginfo si;
- if (sig == SIGSEGV) {
- /*
- * Acquiring siglock around the sa_handler-update is almost
- * certainly overkill, but this isn't a
- * performance-critical path and I'd rather play it safe
- * here than having to debug a nasty race if and when
- * something changes in kernel/signal.c that would make it
- * no longer safe to modify sa_handler without holding the
- * lock.
- */
- spin_lock_irqsave(¤t->sighand->siglock, flags);
- current->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
- spin_unlock_irqrestore(¤t->sighand->siglock, flags);
- }
- si.si_signo = SIGSEGV;
- si.si_errno = 0;
- si.si_code = SI_KERNEL;
- si.si_pid = task_pid_vnr(current);
- si.si_uid = from_kuid_munged(current_user_ns(), current_uid());
- si.si_addr = addr;
- force_sig_info(SIGSEGV, &si, current);
- return 1;
- }
- static long
- setup_frame(struct ksignal *ksig, sigset_t *set, struct sigscratch *scr)
- {
- extern char __kernel_sigtramp[];
- unsigned long tramp_addr, new_rbs = 0, new_sp;
- struct sigframe __user *frame;
- long err;
- new_sp = scr->pt.r12;
- tramp_addr = (unsigned long) __kernel_sigtramp;
- if (ksig->ka.sa.sa_flags & SA_ONSTACK) {
- int onstack = sas_ss_flags(new_sp);
- if (onstack == 0) {
- new_sp = current->sas_ss_sp + current->sas_ss_size;
- /*
- * We need to check for the register stack being on the
- * signal stack separately, because it's switched
- * separately (memory stack is switched in the kernel,
- * register stack is switched in the signal trampoline).
- */
- if (!rbs_on_sig_stack(scr->pt.ar_bspstore))
- new_rbs = ALIGN(current->sas_ss_sp,
- sizeof(long));
- } else if (onstack == SS_ONSTACK) {
- unsigned long check_sp;
- /*
- * If we are on the alternate signal stack and would
- * overflow it, don't. Return an always-bogus address
- * instead so we will die with SIGSEGV.
- */
- check_sp = (new_sp - sizeof(*frame)) & -STACK_ALIGN;
- if (!likely(on_sig_stack(check_sp)))
- return force_sigsegv_info(ksig->sig, (void __user *)
- check_sp);
- }
- }
- frame = (void __user *) ((new_sp - sizeof(*frame)) & -STACK_ALIGN);
- if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
- return force_sigsegv_info(ksig->sig, frame);
- err = __put_user(ksig->sig, &frame->arg0);
- err |= __put_user(&frame->info, &frame->arg1);
- err |= __put_user(&frame->sc, &frame->arg2);
- err |= __put_user(new_rbs, &frame->sc.sc_rbs_base);
- err |= __put_user(0, &frame->sc.sc_loadrs); /* initialize to zero */
- err |= __put_user(ksig->ka.sa.sa_handler, &frame->handler);
- err |= copy_siginfo_to_user(&frame->info, &ksig->info);
- err |= __save_altstack(&frame->sc.sc_stack, scr->pt.r12);
- err |= setup_sigcontext(&frame->sc, set, scr);
- if (unlikely(err))
- return force_sigsegv_info(ksig->sig, frame);
- scr->pt.r12 = (unsigned long) frame - 16; /* new stack pointer */
- scr->pt.ar_fpsr = FPSR_DEFAULT; /* reset fpsr for signal handler */
- scr->pt.cr_iip = tramp_addr;
- ia64_psr(&scr->pt)->ri = 0; /* start executing in first slot */
- ia64_psr(&scr->pt)->be = 0; /* force little-endian byte-order */
- /*
- * Force the interruption function mask to zero. This has no effect when a
- * system-call got interrupted by a signal (since, in that case, scr->pt_cr_ifs is
- * ignored), but it has the desirable effect of making it possible to deliver a
- * signal with an incomplete register frame (which happens when a mandatory RSE
- * load faults). Furthermore, it has no negative effect on the getting the user's
- * dirty partition preserved, because that's governed by scr->pt.loadrs.
- */
- scr->pt.cr_ifs = (1UL << 63);
- /*
- * Note: this affects only the NaT bits of the scratch regs (the ones saved in
- * pt_regs), which is exactly what we want.
- */
- scr->scratch_unat = 0; /* ensure NaT bits of r12 is clear */
- #if DEBUG_SIG
- printk("SIG deliver (%s:%d): sig=%d sp=%lx ip=%lx handler=%p\n",
- current->comm, current->pid, ksig->sig, scr->pt.r12, frame->sc.sc_ip, frame->handler);
- #endif
- return 0;
- }
- static long
- handle_signal (struct ksignal *ksig, struct sigscratch *scr)
- {
- int ret = setup_frame(ksig, sigmask_to_save(), scr);
- if (!ret)
- signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
- return ret;
- }
- /*
- * Note that `init' is a special process: it doesn't get signals it doesn't want to
- * handle. Thus you cannot kill init even with a SIGKILL even by mistake.
- */
- void
- ia64_do_signal (struct sigscratch *scr, long in_syscall)
- {
- long restart = in_syscall;
- long errno = scr->pt.r8;
- struct ksignal ksig;
- /*
- * This only loops in the rare cases of handle_signal() failing, in which case we
- * need to push through a forced SIGSEGV.
- */
- while (1) {
- get_signal(&ksig);
- /*
- * get_signal_to_deliver() may have run a debugger (via notify_parent())
- * and the debugger may have modified the state (e.g., to arrange for an
- * inferior call), thus it's important to check for restarting _after_
- * get_signal_to_deliver().
- */
- if ((long) scr->pt.r10 != -1)
- /*
- * A system calls has to be restarted only if one of the error codes
- * ERESTARTNOHAND, ERESTARTSYS, or ERESTARTNOINTR is returned. If r10
- * isn't -1 then r8 doesn't hold an error code and we don't need to
- * restart the syscall, so we can clear the "restart" flag here.
- */
- restart = 0;
- if (ksig.sig <= 0)
- break;
- if (unlikely(restart)) {
- switch (errno) {
- case ERESTART_RESTARTBLOCK:
- case ERESTARTNOHAND:
- scr->pt.r8 = EINTR;
- /* note: scr->pt.r10 is already -1 */
- break;
- case ERESTARTSYS:
- if ((ksig.ka.sa.sa_flags & SA_RESTART) == 0) {
- scr->pt.r8 = EINTR;
- /* note: scr->pt.r10 is already -1 */
- break;
- }
- case ERESTARTNOINTR:
- ia64_decrement_ip(&scr->pt);
- restart = 0; /* don't restart twice if handle_signal() fails... */
- }
- }
- /*
- * Whee! Actually deliver the signal. If the delivery failed, we need to
- * continue to iterate in this loop so we can deliver the SIGSEGV...
- */
- if (handle_signal(&ksig, scr))
- return;
- }
- /* Did we come from a system call? */
- if (restart) {
- /* Restart the system call - no handlers present */
- if (errno == ERESTARTNOHAND || errno == ERESTARTSYS || errno == ERESTARTNOINTR
- || errno == ERESTART_RESTARTBLOCK)
- {
- /*
- * Note: the syscall number is in r15 which is saved in
- * pt_regs so all we need to do here is adjust ip so that
- * the "break" instruction gets re-executed.
- */
- ia64_decrement_ip(&scr->pt);
- if (errno == ERESTART_RESTARTBLOCK)
- scr->pt.r15 = __NR_restart_syscall;
- }
- }
- /* if there's no signal to deliver, we just put the saved sigmask
- * back */
- restore_saved_sigmask();
- }
|