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413 lines
13 KiB
413 lines
13 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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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 <[email protected]> |
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* |
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* Derived from i386 and Alpha versions. |
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*/ |
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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/tracehook.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/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/intrinsics.h> |
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#include <linux/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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#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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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->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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err |= __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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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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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(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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set_current_blocked(&set); |
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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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if (restore_altstack(&sc->sc_stack)) |
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goto give_sigsegv; |
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return retval; |
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give_sigsegv: |
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force_sig(SIGSEGV); |
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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 = 0; |
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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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err = __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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/* 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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setup_frame(struct ksignal *ksig, sigset_t *set, 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 (ksig->ka.sa.sa_flags & SA_ONSTACK) { |
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int onstack = sas_ss_flags(new_sp); |
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if (onstack == 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 |
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* signal stack separately, because it's switched |
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* separately (memory stack is switched in the kernel, |
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* 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 = ALIGN(current->sas_ss_sp, |
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sizeof(long)); |
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} else if (onstack == SS_ONSTACK) { |
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unsigned long check_sp; |
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/* |
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* If we are on the alternate signal stack and would |
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* overflow it, don't. Return an always-bogus address |
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* instead so we will die with SIGSEGV. |
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*/ |
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check_sp = (new_sp - sizeof(*frame)) & -STACK_ALIGN; |
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if (!likely(on_sig_stack(check_sp))) { |
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force_sigsegv(ksig->sig); |
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return 1; |
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} |
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} |
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} |
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frame = (void __user *) ((new_sp - sizeof(*frame)) & -STACK_ALIGN); |
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if (!access_ok(frame, sizeof(*frame))) { |
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force_sigsegv(ksig->sig); |
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return 1; |
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} |
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err = __put_user(ksig->sig, &frame->arg0); |
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err |= __put_user(&frame->info, &frame->arg1); |
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err |= __put_user(&frame->sc, &frame->arg2); |
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err |= __put_user(new_rbs, &frame->sc.sc_rbs_base); |
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err |= __put_user(0, &frame->sc.sc_loadrs); /* initialize to zero */ |
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err |= __put_user(ksig->ka.sa.sa_handler, &frame->handler); |
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err |= copy_siginfo_to_user(&frame->info, &ksig->info); |
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err |= __save_altstack(&frame->sc.sc_stack, scr->pt.r12); |
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err |= setup_sigcontext(&frame->sc, set, scr); |
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if (unlikely(err)) { |
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force_sigsegv(ksig->sig); |
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return 1; |
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} |
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scr->pt.r12 = (unsigned long) frame - 16; /* new stack pointer */ |
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scr->pt.ar_fpsr = FPSR_DEFAULT; /* reset fpsr for signal handler */ |
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scr->pt.cr_iip = tramp_addr; |
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ia64_psr(&scr->pt)->ri = 0; /* start executing in first slot */ |
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ia64_psr(&scr->pt)->be = 0; /* force little-endian byte-order */ |
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/* |
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* Force the interruption function mask to zero. This has no effect when a |
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* system-call got interrupted by a signal (since, in that case, scr->pt_cr_ifs is |
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* ignored), but it has the desirable effect of making it possible to deliver a |
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* signal with an incomplete register frame (which happens when a mandatory RSE |
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* load faults). Furthermore, it has no negative effect on the getting the user's |
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* dirty partition preserved, because that's governed by scr->pt.loadrs. |
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*/ |
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scr->pt.cr_ifs = (1UL << 63); |
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/* |
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* Note: this affects only the NaT bits of the scratch regs (the ones saved in |
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* pt_regs), which is exactly what we want. |
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*/ |
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scr->scratch_unat = 0; /* ensure NaT bits of r12 is clear */ |
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#if DEBUG_SIG |
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printk("SIG deliver (%s:%d): sig=%d sp=%lx ip=%lx handler=%p\n", |
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current->comm, current->pid, ksig->sig, scr->pt.r12, frame->sc.sc_ip, frame->handler); |
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#endif |
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return 0; |
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} |
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static long |
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handle_signal (struct ksignal *ksig, struct sigscratch *scr) |
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{ |
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int ret = setup_frame(ksig, sigmask_to_save(), scr); |
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if (!ret) |
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signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); |
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return ret; |
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} |
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/* |
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* Note that `init' is a special process: it doesn't get signals it doesn't want to |
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* handle. Thus you cannot kill init even with a SIGKILL even by mistake. |
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*/ |
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void |
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ia64_do_signal (struct sigscratch *scr, long in_syscall) |
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{ |
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long restart = in_syscall; |
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long errno = scr->pt.r8; |
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struct ksignal ksig; |
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/* |
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* This only loops in the rare cases of handle_signal() failing, in which case we |
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* need to push through a forced SIGSEGV. |
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*/ |
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while (1) { |
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if (!get_signal(&ksig)) |
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break; |
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/* |
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* get_signal() may have run a debugger (via notify_parent()) |
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* and the debugger may have modified the state (e.g., to arrange for an |
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* inferior call), thus it's important to check for restarting _after_ |
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* get_signal(). |
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*/ |
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if ((long) scr->pt.r10 != -1) |
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/* |
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* A system calls has to be restarted only if one of the error codes |
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* ERESTARTNOHAND, ERESTARTSYS, or ERESTARTNOINTR is returned. If r10 |
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* isn't -1 then r8 doesn't hold an error code and we don't need to |
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* restart the syscall, so we can clear the "restart" flag here. |
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*/ |
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restart = 0; |
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if (ksig.sig <= 0) |
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break; |
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if (unlikely(restart)) { |
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switch (errno) { |
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case ERESTART_RESTARTBLOCK: |
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case ERESTARTNOHAND: |
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scr->pt.r8 = EINTR; |
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/* note: scr->pt.r10 is already -1 */ |
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break; |
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case ERESTARTSYS: |
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if ((ksig.ka.sa.sa_flags & SA_RESTART) == 0) { |
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scr->pt.r8 = EINTR; |
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/* note: scr->pt.r10 is already -1 */ |
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break; |
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} |
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fallthrough; |
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case ERESTARTNOINTR: |
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ia64_decrement_ip(&scr->pt); |
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restart = 0; /* don't restart twice if handle_signal() fails... */ |
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} |
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} |
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/* |
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* Whee! Actually deliver the signal. If the delivery failed, we need to |
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* continue to iterate in this loop so we can deliver the SIGSEGV... |
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*/ |
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if (handle_signal(&ksig, scr)) |
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return; |
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} |
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/* Did we come from a system call? */ |
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if (restart) { |
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/* Restart the system call - no handlers present */ |
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if (errno == ERESTARTNOHAND || errno == ERESTARTSYS || errno == ERESTARTNOINTR |
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|| errno == ERESTART_RESTARTBLOCK) |
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{ |
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/* |
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* Note: the syscall number is in r15 which is saved in |
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* pt_regs so all we need to do here is adjust ip so that |
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* the "break" instruction gets re-executed. |
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*/ |
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ia64_decrement_ip(&scr->pt); |
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if (errno == ERESTART_RESTARTBLOCK) |
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scr->pt.r15 = __NR_restart_syscall; |
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} |
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} |
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/* if there's no signal to deliver, we just put the saved sigmask |
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* back */ |
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restore_saved_sigmask(); |
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}
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