![David Mosberger-Tang](/assets/img/avatar_default.png)
At the moment, attempting to invoke a signal-handler on the normal stack is guaranteed to fail if the stack-pointer happens not to be 16-byte aligned. This is because the signal-trampoline will attempt to store fp-regs with stf.spill instructions, which will trap for misaligned addresses. This isn't terribly useful behavior. It's better to just always align the signal frame to the next lower 16-byte boundary. Signed-off-by: David Mosberger-Tang <David.Mosberger@acm.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
692 lines
22 KiB
C
692 lines
22 KiB
C
/*
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* Architecture-specific signal handling support.
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*
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* Copyright (C) 1999-2004 Hewlett-Packard Co
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* David Mosberger-Tang <davidm@hpl.hp.com>
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*
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* Derived from i386 and Alpha versions.
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*/
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#include <linux/config.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/ptrace.h>
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#include <linux/sched.h>
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#include <linux/signal.h>
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#include <linux/smp.h>
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#include <linux/smp_lock.h>
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#include <linux/stddef.h>
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#include <linux/tty.h>
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#include <linux/binfmts.h>
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#include <linux/unistd.h>
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#include <linux/wait.h>
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#include <asm/ia32.h>
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#include <asm/intrinsics.h>
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#include <asm/uaccess.h>
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#include <asm/rse.h>
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#include <asm/sigcontext.h>
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#include "sigframe.h"
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#define DEBUG_SIG 0
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#define STACK_ALIGN 16 /* minimal alignment for stack pointer */
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#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
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#if _NSIG_WORDS > 1
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# define PUT_SIGSET(k,u) __copy_to_user((u)->sig, (k)->sig, sizeof(sigset_t))
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# define GET_SIGSET(k,u) __copy_from_user((k)->sig, (u)->sig, sizeof(sigset_t))
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#else
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# define PUT_SIGSET(k,u) __put_user((k)->sig[0], &(u)->sig[0])
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# define GET_SIGSET(k,u) __get_user((k)->sig[0], &(u)->sig[0])
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#endif
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long
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ia64_rt_sigsuspend (sigset_t __user *uset, size_t sigsetsize, struct sigscratch *scr)
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{
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sigset_t oldset, set;
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/* XXX: Don't preclude handling different sized sigset_t's. */
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if (sigsetsize != sizeof(sigset_t))
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return -EINVAL;
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if (!access_ok(VERIFY_READ, uset, sigsetsize))
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return -EFAULT;
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if (GET_SIGSET(&set, uset))
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return -EFAULT;
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sigdelsetmask(&set, ~_BLOCKABLE);
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spin_lock_irq(¤t->sighand->siglock);
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{
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oldset = current->blocked;
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current->blocked = set;
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recalc_sigpending();
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}
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spin_unlock_irq(¤t->sighand->siglock);
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/*
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* The return below usually returns to the signal handler. We need to
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* pre-set the correct error code here to ensure that the right values
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* get saved in sigcontext by ia64_do_signal.
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*/
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scr->pt.r8 = EINTR;
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scr->pt.r10 = -1;
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while (1) {
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current->state = TASK_INTERRUPTIBLE;
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schedule();
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if (ia64_do_signal(&oldset, scr, 1))
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return -EINTR;
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}
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}
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asmlinkage long
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sys_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, long arg2,
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long arg3, long arg4, long arg5, long arg6, long arg7,
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struct pt_regs regs)
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{
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return do_sigaltstack(uss, uoss, regs.r12);
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}
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static long
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restore_sigcontext (struct sigcontext __user *sc, struct sigscratch *scr)
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{
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unsigned long ip, flags, nat, um, cfm, rsc;
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long err;
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/* Always make any pending restarted system calls return -EINTR */
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current_thread_info()->restart_block.fn = do_no_restart_syscall;
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/* restore scratch that always needs gets updated during signal delivery: */
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err = __get_user(flags, &sc->sc_flags);
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err |= __get_user(nat, &sc->sc_nat);
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err |= __get_user(ip, &sc->sc_ip); /* instruction pointer */
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err |= __get_user(cfm, &sc->sc_cfm);
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err |= __get_user(um, &sc->sc_um); /* user mask */
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err |= __get_user(rsc, &sc->sc_ar_rsc);
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err |= __get_user(scr->pt.ar_unat, &sc->sc_ar_unat);
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err |= __get_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr);
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err |= __get_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
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err |= __get_user(scr->pt.pr, &sc->sc_pr); /* predicates */
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err |= __get_user(scr->pt.b0, &sc->sc_br[0]); /* b0 (rp) */
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err |= __get_user(scr->pt.b6, &sc->sc_br[6]); /* b6 */
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err |= __copy_from_user(&scr->pt.r1, &sc->sc_gr[1], 8); /* r1 */
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err |= __copy_from_user(&scr->pt.r8, &sc->sc_gr[8], 4*8); /* r8-r11 */
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err |= __copy_from_user(&scr->pt.r12, &sc->sc_gr[12], 2*8); /* r12-r13 */
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err |= __copy_from_user(&scr->pt.r15, &sc->sc_gr[15], 8); /* r15 */
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scr->pt.cr_ifs = cfm | (1UL << 63);
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scr->pt.ar_rsc = rsc | (3 << 2); /* force PL3 */
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/* establish new instruction pointer: */
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scr->pt.cr_iip = ip & ~0x3UL;
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ia64_psr(&scr->pt)->ri = ip & 0x3;
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scr->pt.cr_ipsr = (scr->pt.cr_ipsr & ~IA64_PSR_UM) | (um & IA64_PSR_UM);
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scr->scratch_unat = ia64_put_scratch_nat_bits(&scr->pt, nat);
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if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) {
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/* Restore most scratch-state only when not in syscall. */
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err |= __get_user(scr->pt.ar_ccv, &sc->sc_ar_ccv); /* ar.ccv */
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err |= __get_user(scr->pt.b7, &sc->sc_br[7]); /* b7 */
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err |= __get_user(scr->pt.r14, &sc->sc_gr[14]); /* r14 */
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err |= __copy_from_user(&scr->pt.ar_csd, &sc->sc_ar25, 2*8); /* ar.csd & ar.ssd */
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err |= __copy_from_user(&scr->pt.r2, &sc->sc_gr[2], 2*8); /* r2-r3 */
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err |= __copy_from_user(&scr->pt.r16, &sc->sc_gr[16], 16*8); /* r16-r31 */
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}
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if ((flags & IA64_SC_FLAG_FPH_VALID) != 0) {
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struct ia64_psr *psr = ia64_psr(&scr->pt);
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__copy_from_user(current->thread.fph, &sc->sc_fr[32], 96*16);
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psr->mfh = 0; /* drop signal handler's fph contents... */
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preempt_disable();
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if (psr->dfh)
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ia64_drop_fpu(current);
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else {
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/* We already own the local fph, otherwise psr->dfh wouldn't be 0. */
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__ia64_load_fpu(current->thread.fph);
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ia64_set_local_fpu_owner(current);
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}
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preempt_enable();
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}
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return err;
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}
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int
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copy_siginfo_to_user (siginfo_t __user *to, siginfo_t *from)
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{
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if (!access_ok(VERIFY_WRITE, to, sizeof(siginfo_t)))
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return -EFAULT;
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if (from->si_code < 0) {
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if (__copy_to_user(to, from, sizeof(siginfo_t)))
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return -EFAULT;
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return 0;
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} else {
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int err;
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/*
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* If you change siginfo_t structure, please be sure this code is fixed
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* accordingly. It should never copy any pad contained in the structure
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* to avoid security leaks, but must copy the generic 3 ints plus the
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* relevant union member.
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*/
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err = __put_user(from->si_signo, &to->si_signo);
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err |= __put_user(from->si_errno, &to->si_errno);
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err |= __put_user((short)from->si_code, &to->si_code);
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switch (from->si_code >> 16) {
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case __SI_FAULT >> 16:
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err |= __put_user(from->si_flags, &to->si_flags);
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err |= __put_user(from->si_isr, &to->si_isr);
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case __SI_POLL >> 16:
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err |= __put_user(from->si_addr, &to->si_addr);
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err |= __put_user(from->si_imm, &to->si_imm);
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break;
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case __SI_TIMER >> 16:
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err |= __put_user(from->si_tid, &to->si_tid);
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err |= __put_user(from->si_overrun, &to->si_overrun);
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err |= __put_user(from->si_ptr, &to->si_ptr);
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break;
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case __SI_RT >> 16: /* Not generated by the kernel as of now. */
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case __SI_MESGQ >> 16:
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err |= __put_user(from->si_uid, &to->si_uid);
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err |= __put_user(from->si_pid, &to->si_pid);
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err |= __put_user(from->si_ptr, &to->si_ptr);
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break;
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case __SI_CHLD >> 16:
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err |= __put_user(from->si_utime, &to->si_utime);
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err |= __put_user(from->si_stime, &to->si_stime);
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err |= __put_user(from->si_status, &to->si_status);
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default:
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err |= __put_user(from->si_uid, &to->si_uid);
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err |= __put_user(from->si_pid, &to->si_pid);
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break;
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}
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return err;
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}
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}
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long
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ia64_rt_sigreturn (struct sigscratch *scr)
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{
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extern char ia64_strace_leave_kernel, ia64_leave_kernel;
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struct sigcontext __user *sc;
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struct siginfo si;
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sigset_t set;
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long retval;
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sc = &((struct sigframe __user *) (scr->pt.r12 + 16))->sc;
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/*
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* When we return to the previously executing context, r8 and r10 have already
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* been setup the way we want them. Indeed, if the signal wasn't delivered while
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* in a system call, we must not touch r8 or r10 as otherwise user-level state
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* could be corrupted.
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*/
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retval = (long) &ia64_leave_kernel;
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if (test_thread_flag(TIF_SYSCALL_TRACE)
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|| test_thread_flag(TIF_SYSCALL_AUDIT))
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/*
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* strace expects to be notified after sigreturn returns even though the
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* context to which we return may not be in the middle of a syscall.
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* Thus, the return-value that strace displays for sigreturn is
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* meaningless.
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*/
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retval = (long) &ia64_strace_leave_kernel;
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if (!access_ok(VERIFY_READ, sc, sizeof(*sc)))
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goto give_sigsegv;
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if (GET_SIGSET(&set, &sc->sc_mask))
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goto give_sigsegv;
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sigdelsetmask(&set, ~_BLOCKABLE);
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spin_lock_irq(¤t->sighand->siglock);
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{
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current->blocked = set;
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recalc_sigpending();
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}
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spin_unlock_irq(¤t->sighand->siglock);
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if (restore_sigcontext(sc, scr))
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goto give_sigsegv;
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#if DEBUG_SIG
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printk("SIG return (%s:%d): sp=%lx ip=%lx\n",
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current->comm, current->pid, scr->pt.r12, scr->pt.cr_iip);
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#endif
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/*
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* It is more difficult to avoid calling this function than to
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* call it and ignore errors.
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*/
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do_sigaltstack(&sc->sc_stack, NULL, scr->pt.r12);
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return retval;
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give_sigsegv:
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si.si_signo = SIGSEGV;
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si.si_errno = 0;
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si.si_code = SI_KERNEL;
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si.si_pid = current->pid;
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si.si_uid = current->uid;
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si.si_addr = sc;
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force_sig_info(SIGSEGV, &si, current);
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return retval;
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}
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/*
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* This does just the minimum required setup of sigcontext.
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* Specifically, it only installs data that is either not knowable at
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* the user-level or that gets modified before execution in the
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* trampoline starts. Everything else is done at the user-level.
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*/
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static long
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setup_sigcontext (struct sigcontext __user *sc, sigset_t *mask, struct sigscratch *scr)
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{
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unsigned long flags = 0, ifs, cfm, nat;
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long err;
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ifs = scr->pt.cr_ifs;
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if (on_sig_stack((unsigned long) sc))
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flags |= IA64_SC_FLAG_ONSTACK;
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if ((ifs & (1UL << 63)) == 0)
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/* if cr_ifs doesn't have the valid bit set, we got here through a syscall */
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flags |= IA64_SC_FLAG_IN_SYSCALL;
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cfm = ifs & ((1UL << 38) - 1);
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ia64_flush_fph(current);
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if ((current->thread.flags & IA64_THREAD_FPH_VALID)) {
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flags |= IA64_SC_FLAG_FPH_VALID;
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__copy_to_user(&sc->sc_fr[32], current->thread.fph, 96*16);
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}
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nat = ia64_get_scratch_nat_bits(&scr->pt, scr->scratch_unat);
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err = __put_user(flags, &sc->sc_flags);
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err |= __put_user(nat, &sc->sc_nat);
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err |= PUT_SIGSET(mask, &sc->sc_mask);
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err |= __put_user(cfm, &sc->sc_cfm);
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err |= __put_user(scr->pt.cr_ipsr & IA64_PSR_UM, &sc->sc_um);
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err |= __put_user(scr->pt.ar_rsc, &sc->sc_ar_rsc);
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err |= __put_user(scr->pt.ar_unat, &sc->sc_ar_unat); /* ar.unat */
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err |= __put_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr); /* ar.fpsr */
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err |= __put_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
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err |= __put_user(scr->pt.pr, &sc->sc_pr); /* predicates */
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err |= __put_user(scr->pt.b0, &sc->sc_br[0]); /* b0 (rp) */
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err |= __put_user(scr->pt.b6, &sc->sc_br[6]); /* b6 */
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err |= __copy_to_user(&sc->sc_gr[1], &scr->pt.r1, 8); /* r1 */
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err |= __copy_to_user(&sc->sc_gr[8], &scr->pt.r8, 4*8); /* r8-r11 */
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err |= __copy_to_user(&sc->sc_gr[12], &scr->pt.r12, 2*8); /* r12-r13 */
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err |= __copy_to_user(&sc->sc_gr[15], &scr->pt.r15, 8); /* r15 */
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err |= __put_user(scr->pt.cr_iip + ia64_psr(&scr->pt)->ri, &sc->sc_ip);
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if (flags & IA64_SC_FLAG_IN_SYSCALL) {
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/* Clear scratch registers if the signal interrupted a system call. */
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err |= __put_user(0, &sc->sc_ar_ccv); /* ar.ccv */
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err |= __put_user(0, &sc->sc_br[7]); /* b7 */
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err |= __put_user(0, &sc->sc_gr[14]); /* r14 */
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err |= __clear_user(&sc->sc_ar25, 2*8); /* ar.csd & ar.ssd */
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err |= __clear_user(&sc->sc_gr[2], 2*8); /* r2-r3 */
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err |= __clear_user(&sc->sc_gr[16], 16*8); /* r16-r31 */
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} else {
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/* Copy scratch regs to sigcontext if the signal didn't interrupt a syscall. */
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err |= __put_user(scr->pt.ar_ccv, &sc->sc_ar_ccv); /* ar.ccv */
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err |= __put_user(scr->pt.b7, &sc->sc_br[7]); /* b7 */
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err |= __put_user(scr->pt.r14, &sc->sc_gr[14]); /* r14 */
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err |= __copy_to_user(&sc->sc_ar25, &scr->pt.ar_csd, 2*8); /* ar.csd & ar.ssd */
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err |= __copy_to_user(&sc->sc_gr[2], &scr->pt.r2, 2*8); /* r2-r3 */
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err |= __copy_to_user(&sc->sc_gr[16], &scr->pt.r16, 16*8); /* r16-r31 */
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}
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return err;
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}
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/*
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* Check whether the register-backing store is already on the signal stack.
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*/
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static inline int
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rbs_on_sig_stack (unsigned long bsp)
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{
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return (bsp - current->sas_ss_sp < current->sas_ss_size);
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}
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static long
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force_sigsegv_info (int sig, void __user *addr)
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{
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unsigned long flags;
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struct siginfo si;
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if (sig == SIGSEGV) {
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/*
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* Acquiring siglock around the sa_handler-update is almost
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* certainly overkill, but this isn't a
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* performance-critical path and I'd rather play it safe
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* here than having to debug a nasty race if and when
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* something changes in kernel/signal.c that would make it
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* no longer safe to modify sa_handler without holding the
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* lock.
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*/
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spin_lock_irqsave(¤t->sighand->siglock, flags);
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current->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
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spin_unlock_irqrestore(¤t->sighand->siglock, flags);
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}
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si.si_signo = SIGSEGV;
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si.si_errno = 0;
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si.si_code = SI_KERNEL;
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si.si_pid = current->pid;
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si.si_uid = current->uid;
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si.si_addr = addr;
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force_sig_info(SIGSEGV, &si, current);
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return 0;
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}
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static long
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setup_frame (int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set,
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struct sigscratch *scr)
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{
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extern char __kernel_sigtramp[];
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unsigned long tramp_addr, new_rbs = 0, new_sp;
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struct sigframe __user *frame;
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long err;
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new_sp = scr->pt.r12;
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tramp_addr = (unsigned long) __kernel_sigtramp;
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if ((ka->sa.sa_flags & SA_ONSTACK) && sas_ss_flags(new_sp) == 0) {
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new_sp = current->sas_ss_sp + current->sas_ss_size;
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/*
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* We need to check for the register stack being on the signal stack
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* separately, because it's switched separately (memory stack is switched
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* in the kernel, register stack is switched in the signal trampoline).
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*/
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if (!rbs_on_sig_stack(scr->pt.ar_bspstore))
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new_rbs = (current->sas_ss_sp + sizeof(long) - 1) & ~(sizeof(long) - 1);
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}
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frame = (void __user *) ((new_sp - sizeof(*frame)) & -STACK_ALIGN);
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if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
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return force_sigsegv_info(sig, frame);
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|
|
|
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.
|
|
*/
|
|
long
|
|
ia64_do_signal (sigset_t *oldset, struct sigscratch *scr, long in_syscall)
|
|
{
|
|
struct k_sigaction ka;
|
|
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 0;
|
|
|
|
if (!oldset)
|
|
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))
|
|
return 1;
|
|
}
|
|
|
|
/* 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;
|
|
}
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* Set a delayed signal that was detected in MCA/INIT/NMI/PMI context where it
|
|
* could not be delivered. It is important that the target process is not
|
|
* allowed to do any more work in user space. Possible cases for the target
|
|
* process:
|
|
*
|
|
* - It is sleeping and will wake up soon. Store the data in the current task,
|
|
* the signal will be sent when the current task returns from the next
|
|
* interrupt.
|
|
*
|
|
* - It is running in user context. Store the data in the current task, the
|
|
* signal will be sent when the current task returns from the next interrupt.
|
|
*
|
|
* - It is running in kernel context on this or another cpu and will return to
|
|
* user context. Store the data in the target task, the signal will be sent
|
|
* to itself when the target task returns to user space.
|
|
*
|
|
* - It is running in kernel context on this cpu and will sleep before
|
|
* returning to user context. Because this is also the current task, the
|
|
* signal will not get delivered and the task could sleep indefinitely.
|
|
* Store the data in the idle task for this cpu, the signal will be sent
|
|
* after the idle task processes its next interrupt.
|
|
*
|
|
* To cover all cases, store the data in the target task, the current task and
|
|
* the idle task on this cpu. Whatever happens, the signal will be delivered
|
|
* to the target task before it can do any useful user space work. Multiple
|
|
* deliveries have no unwanted side effects.
|
|
*
|
|
* Note: This code is executed in MCA/INIT/NMI/PMI context, with interrupts
|
|
* disabled. It must not take any locks nor use kernel structures or services
|
|
* that require locks.
|
|
*/
|
|
|
|
/* To ensure that we get the right pid, check its start time. To avoid extra
|
|
* include files in thread_info.h, convert the task start_time to unsigned long,
|
|
* giving us a cycle time of > 580 years.
|
|
*/
|
|
static inline unsigned long
|
|
start_time_ul(const struct task_struct *t)
|
|
{
|
|
return t->start_time.tv_sec * NSEC_PER_SEC + t->start_time.tv_nsec;
|
|
}
|
|
|
|
void
|
|
set_sigdelayed(pid_t pid, int signo, int code, void __user *addr)
|
|
{
|
|
struct task_struct *t;
|
|
unsigned long start_time = 0;
|
|
int i;
|
|
|
|
for (i = 1; i <= 3; ++i) {
|
|
switch (i) {
|
|
case 1:
|
|
t = find_task_by_pid(pid);
|
|
if (t)
|
|
start_time = start_time_ul(t);
|
|
break;
|
|
case 2:
|
|
t = current;
|
|
break;
|
|
default:
|
|
t = idle_task(smp_processor_id());
|
|
break;
|
|
}
|
|
|
|
if (!t)
|
|
return;
|
|
t->thread_info->sigdelayed.signo = signo;
|
|
t->thread_info->sigdelayed.code = code;
|
|
t->thread_info->sigdelayed.addr = addr;
|
|
t->thread_info->sigdelayed.start_time = start_time;
|
|
t->thread_info->sigdelayed.pid = pid;
|
|
wmb();
|
|
set_tsk_thread_flag(t, TIF_SIGDELAYED);
|
|
}
|
|
}
|
|
|
|
/* Called from entry.S when it detects TIF_SIGDELAYED, a delayed signal that
|
|
* was detected in MCA/INIT/NMI/PMI context where it could not be delivered.
|
|
*/
|
|
|
|
void
|
|
do_sigdelayed(void)
|
|
{
|
|
struct siginfo siginfo;
|
|
pid_t pid;
|
|
struct task_struct *t;
|
|
|
|
clear_thread_flag(TIF_SIGDELAYED);
|
|
memset(&siginfo, 0, sizeof(siginfo));
|
|
siginfo.si_signo = current_thread_info()->sigdelayed.signo;
|
|
siginfo.si_code = current_thread_info()->sigdelayed.code;
|
|
siginfo.si_addr = current_thread_info()->sigdelayed.addr;
|
|
pid = current_thread_info()->sigdelayed.pid;
|
|
t = find_task_by_pid(pid);
|
|
if (!t)
|
|
return;
|
|
if (current_thread_info()->sigdelayed.start_time != start_time_ul(t))
|
|
return;
|
|
force_sig_info(siginfo.si_signo, &siginfo, t);
|
|
}
|