/* * 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/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/ia32.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 */ #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) #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 asmlinkage long sys_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, long arg2, long arg3, long arg4, long arg5, long arg6, long arg7, struct pt_regs regs) { return do_sigaltstack(uss, uoss, regs.r12); } 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_thread_info()->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, 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; sigdelsetmask(&set, ~_BLOCKABLE); spin_lock_irq(¤t->sighand->siglock); { current->blocked = set; recalc_sigpending(); } spin_unlock_irq(¤t->sighand->siglock); 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 /* * It is more difficult to avoid calling this function than to * call it and ignore errors. */ do_sigaltstack(&sc->sc_stack, NULL, scr->pt.r12); 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 = 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 = current->uid; si.si_addr = addr; force_sig_info(SIGSEGV, &si, current); return 0; } static long setup_frame (int sig, struct k_sigaction *ka, siginfo_t *info, 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 (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(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(sig, frame); err = __put_user(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(ka->sa.sa_handler, &frame->handler); err |= copy_siginfo_to_user(&frame->info, info); err |= __put_user(current->sas_ss_sp, &frame->sc.sc_stack.ss_sp); err |= __put_user(current->sas_ss_size, &frame->sc.sc_stack.ss_size); err |= __put_user(sas_ss_flags(scr->pt.r12), &frame->sc.sc_stack.ss_flags); err |= setup_sigcontext(&frame->sc, set, scr); if (unlikely(err)) return force_sigsegv_info(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, sig, scr->pt.r12, frame->sc.sc_ip, frame->handler); #endif return 1; } static long handle_signal (unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *oldset, struct sigscratch *scr) { if (IS_IA32_PROCESS(&scr->pt)) { /* send signal to IA-32 process */ if (!ia32_setup_frame1(sig, ka, info, oldset, &scr->pt)) return 0; } else /* send signal to IA-64 process */ if (!setup_frame(sig, ka, info, oldset, scr)) return 0; spin_lock_irq(¤t->sighand->siglock); sigorsets(¤t->blocked, ¤t->blocked, &ka->sa.sa_mask); if (!(ka->sa.sa_flags & SA_NODEFER)) sigaddset(¤t->blocked, sig); recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); return 1; } /* * 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) { struct k_sigaction ka; sigset_t *oldset; siginfo_t info; long restart = in_syscall; long errno = scr->pt.r8; # define ERR_CODE(c) (IS_IA32_PROCESS(&scr->pt) ? -(c) : (c)) /* * In the ia64_leave_kernel code path, we want the common case to go fast, which * is why we may in certain cases get here from kernel mode. Just return without * doing anything if so. */ if (!user_mode(&scr->pt)) return; if (test_thread_flag(TIF_RESTORE_SIGMASK)) oldset = ¤t->saved_sigmask; else oldset = ¤t->blocked; /* * This only loops in the rare cases of handle_signal() failing, in which case we * need to push through a forced SIGSEGV. */ while (1) { int signr = get_signal_to_deliver(&info, &ka, &scr->pt, NULL); /* * 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 (IS_IA32_PROCESS(&scr->pt)) { if (in_syscall) { if (errno >= 0) restart = 0; else errno = -errno; } } else 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 (signr <= 0) break; if (unlikely(restart)) { switch (errno) { case ERESTART_RESTARTBLOCK: case ERESTARTNOHAND: scr->pt.r8 = ERR_CODE(EINTR); /* note: scr->pt.r10 is already -1 */ break; case ERESTARTSYS: if ((ka.sa.sa_flags & SA_RESTART) == 0) { scr->pt.r8 = ERR_CODE(EINTR); /* note: scr->pt.r10 is already -1 */ break; } case ERESTARTNOINTR: if (IS_IA32_PROCESS(&scr->pt)) { scr->pt.r8 = scr->pt.r1; scr->pt.cr_iip -= 2; } else 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(signr, &ka, &info, oldset, scr)) { /* a signal was successfully delivered; the saved * sigmask will have been stored in the signal frame, * and will be restored by sigreturn, so we can simply * clear the TIF_RESTORE_SIGMASK flag */ if (test_thread_flag(TIF_RESTORE_SIGMASK)) clear_thread_flag(TIF_RESTORE_SIGMASK); 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) { if (IS_IA32_PROCESS(&scr->pt)) { scr->pt.r8 = scr->pt.r1; scr->pt.cr_iip -= 2; if (errno == ERESTART_RESTARTBLOCK) scr->pt.r8 = 0; /* x86 version of __NR_restart_syscall */ } else { /* * 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 */ if (test_thread_flag(TIF_RESTORE_SIGMASK)) { clear_thread_flag(TIF_RESTORE_SIGMASK); sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); } }