542 строки
15 KiB
C
542 строки
15 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/arch/alpha/kernel/signal.c
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*
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* Copyright (C) 1995 Linus Torvalds
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*
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* 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
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*/
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#include <linux/sched/signal.h>
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#include <linux/sched/task_stack.h>
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#include <linux/kernel.h>
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#include <linux/signal.h>
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#include <linux/errno.h>
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#include <linux/wait.h>
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#include <linux/ptrace.h>
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#include <linux/unistd.h>
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#include <linux/mm.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/bitops.h>
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#include <linux/syscalls.h>
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#include <linux/tracehook.h>
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#include <linux/uaccess.h>
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#include <asm/sigcontext.h>
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#include <asm/ucontext.h>
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#include "proto.h"
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#define DEBUG_SIG 0
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#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
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asmlinkage void ret_from_sys_call(void);
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/*
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* The OSF/1 sigprocmask calling sequence is different from the
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* C sigprocmask() sequence..
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*/
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SYSCALL_DEFINE2(osf_sigprocmask, int, how, unsigned long, newmask)
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{
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sigset_t oldmask;
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sigset_t mask;
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unsigned long res;
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siginitset(&mask, newmask & _BLOCKABLE);
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res = sigprocmask(how, &mask, &oldmask);
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if (!res) {
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force_successful_syscall_return();
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res = oldmask.sig[0];
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}
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return res;
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}
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SYSCALL_DEFINE3(osf_sigaction, int, sig,
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const struct osf_sigaction __user *, act,
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struct osf_sigaction __user *, oact)
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{
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struct k_sigaction new_ka, old_ka;
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int ret;
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if (act) {
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old_sigset_t mask;
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if (!access_ok(act, sizeof(*act)) ||
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__get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
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__get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
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__get_user(mask, &act->sa_mask))
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return -EFAULT;
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siginitset(&new_ka.sa.sa_mask, mask);
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new_ka.ka_restorer = NULL;
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}
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ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
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if (!ret && oact) {
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if (!access_ok(oact, sizeof(*oact)) ||
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__put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
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__put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
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__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
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return -EFAULT;
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}
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return ret;
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}
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SYSCALL_DEFINE5(rt_sigaction, int, sig, const struct sigaction __user *, act,
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struct sigaction __user *, oact,
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size_t, sigsetsize, void __user *, restorer)
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{
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struct k_sigaction new_ka, old_ka;
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int ret;
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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 (act) {
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new_ka.ka_restorer = restorer;
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if (copy_from_user(&new_ka.sa, act, sizeof(*act)))
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return -EFAULT;
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}
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ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
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if (!ret && oact) {
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if (copy_to_user(oact, &old_ka.sa, sizeof(*oact)))
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return -EFAULT;
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}
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return ret;
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}
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/*
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* Do a signal return; undo the signal stack.
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*/
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#if _NSIG_WORDS > 1
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# error "Non SA_SIGINFO frame needs rearranging"
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#endif
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struct sigframe
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{
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struct sigcontext sc;
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unsigned int retcode[3];
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};
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struct rt_sigframe
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{
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struct siginfo info;
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struct ucontext uc;
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unsigned int retcode[3];
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};
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/* If this changes, userland unwinders that Know Things about our signal
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frame will break. Do not undertake lightly. It also implies an ABI
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change wrt the size of siginfo_t, which may cause some pain. */
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extern char compile_time_assert
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[offsetof(struct rt_sigframe, uc.uc_mcontext) == 176 ? 1 : -1];
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#define INSN_MOV_R30_R16 0x47fe0410
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#define INSN_LDI_R0 0x201f0000
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#define INSN_CALLSYS 0x00000083
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static long
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restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
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{
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unsigned long usp;
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struct switch_stack *sw = (struct switch_stack *)regs - 1;
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long i, err = __get_user(regs->pc, &sc->sc_pc);
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current->restart_block.fn = do_no_restart_syscall;
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sw->r26 = (unsigned long) ret_from_sys_call;
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err |= __get_user(regs->r0, sc->sc_regs+0);
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err |= __get_user(regs->r1, sc->sc_regs+1);
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err |= __get_user(regs->r2, sc->sc_regs+2);
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err |= __get_user(regs->r3, sc->sc_regs+3);
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err |= __get_user(regs->r4, sc->sc_regs+4);
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err |= __get_user(regs->r5, sc->sc_regs+5);
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err |= __get_user(regs->r6, sc->sc_regs+6);
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err |= __get_user(regs->r7, sc->sc_regs+7);
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err |= __get_user(regs->r8, sc->sc_regs+8);
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err |= __get_user(sw->r9, sc->sc_regs+9);
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err |= __get_user(sw->r10, sc->sc_regs+10);
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err |= __get_user(sw->r11, sc->sc_regs+11);
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err |= __get_user(sw->r12, sc->sc_regs+12);
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err |= __get_user(sw->r13, sc->sc_regs+13);
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err |= __get_user(sw->r14, sc->sc_regs+14);
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err |= __get_user(sw->r15, sc->sc_regs+15);
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err |= __get_user(regs->r16, sc->sc_regs+16);
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err |= __get_user(regs->r17, sc->sc_regs+17);
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err |= __get_user(regs->r18, sc->sc_regs+18);
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err |= __get_user(regs->r19, sc->sc_regs+19);
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err |= __get_user(regs->r20, sc->sc_regs+20);
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err |= __get_user(regs->r21, sc->sc_regs+21);
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err |= __get_user(regs->r22, sc->sc_regs+22);
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err |= __get_user(regs->r23, sc->sc_regs+23);
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err |= __get_user(regs->r24, sc->sc_regs+24);
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err |= __get_user(regs->r25, sc->sc_regs+25);
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err |= __get_user(regs->r26, sc->sc_regs+26);
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err |= __get_user(regs->r27, sc->sc_regs+27);
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err |= __get_user(regs->r28, sc->sc_regs+28);
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err |= __get_user(regs->gp, sc->sc_regs+29);
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err |= __get_user(usp, sc->sc_regs+30);
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wrusp(usp);
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for (i = 0; i < 31; i++)
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err |= __get_user(sw->fp[i], sc->sc_fpregs+i);
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err |= __get_user(sw->fp[31], &sc->sc_fpcr);
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return err;
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}
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/* Note that this syscall is also used by setcontext(3) to install
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a given sigcontext. This because it's impossible to set *all*
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registers and transfer control from userland. */
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asmlinkage void
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do_sigreturn(struct sigcontext __user *sc)
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{
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struct pt_regs *regs = current_pt_regs();
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sigset_t set;
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/* Verify that it's a good sigcontext before using it */
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if (!access_ok(sc, sizeof(*sc)))
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goto give_sigsegv;
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if (__get_user(set.sig[0], &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, regs))
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goto give_sigsegv;
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/* Send SIGTRAP if we're single-stepping: */
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if (ptrace_cancel_bpt (current)) {
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send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *) regs->pc, 0,
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current);
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}
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return;
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give_sigsegv:
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force_sig(SIGSEGV);
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}
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asmlinkage void
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do_rt_sigreturn(struct rt_sigframe __user *frame)
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{
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struct pt_regs *regs = current_pt_regs();
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sigset_t set;
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/* Verify that it's a good ucontext_t before using it */
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if (!access_ok(&frame->uc, sizeof(frame->uc)))
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goto give_sigsegv;
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if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
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goto give_sigsegv;
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set_current_blocked(&set);
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if (restore_sigcontext(&frame->uc.uc_mcontext, regs))
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goto give_sigsegv;
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/* Send SIGTRAP if we're single-stepping: */
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if (ptrace_cancel_bpt (current)) {
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send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *) regs->pc, 0,
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current);
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}
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return;
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give_sigsegv:
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force_sig(SIGSEGV);
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}
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/*
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* Set up a signal frame.
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*/
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static inline void __user *
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get_sigframe(struct ksignal *ksig, unsigned long sp, size_t frame_size)
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{
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return (void __user *)((sigsp(sp, ksig) - frame_size) & -32ul);
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}
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static long
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setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
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unsigned long mask, unsigned long sp)
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{
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struct switch_stack *sw = (struct switch_stack *)regs - 1;
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long i, err = 0;
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err |= __put_user(on_sig_stack((unsigned long)sc), &sc->sc_onstack);
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err |= __put_user(mask, &sc->sc_mask);
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err |= __put_user(regs->pc, &sc->sc_pc);
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err |= __put_user(8, &sc->sc_ps);
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err |= __put_user(regs->r0 , sc->sc_regs+0);
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err |= __put_user(regs->r1 , sc->sc_regs+1);
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err |= __put_user(regs->r2 , sc->sc_regs+2);
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err |= __put_user(regs->r3 , sc->sc_regs+3);
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err |= __put_user(regs->r4 , sc->sc_regs+4);
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err |= __put_user(regs->r5 , sc->sc_regs+5);
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err |= __put_user(regs->r6 , sc->sc_regs+6);
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err |= __put_user(regs->r7 , sc->sc_regs+7);
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err |= __put_user(regs->r8 , sc->sc_regs+8);
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err |= __put_user(sw->r9 , sc->sc_regs+9);
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err |= __put_user(sw->r10 , sc->sc_regs+10);
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err |= __put_user(sw->r11 , sc->sc_regs+11);
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err |= __put_user(sw->r12 , sc->sc_regs+12);
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err |= __put_user(sw->r13 , sc->sc_regs+13);
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err |= __put_user(sw->r14 , sc->sc_regs+14);
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err |= __put_user(sw->r15 , sc->sc_regs+15);
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err |= __put_user(regs->r16, sc->sc_regs+16);
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err |= __put_user(regs->r17, sc->sc_regs+17);
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err |= __put_user(regs->r18, sc->sc_regs+18);
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err |= __put_user(regs->r19, sc->sc_regs+19);
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err |= __put_user(regs->r20, sc->sc_regs+20);
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err |= __put_user(regs->r21, sc->sc_regs+21);
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err |= __put_user(regs->r22, sc->sc_regs+22);
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err |= __put_user(regs->r23, sc->sc_regs+23);
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err |= __put_user(regs->r24, sc->sc_regs+24);
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err |= __put_user(regs->r25, sc->sc_regs+25);
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err |= __put_user(regs->r26, sc->sc_regs+26);
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err |= __put_user(regs->r27, sc->sc_regs+27);
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err |= __put_user(regs->r28, sc->sc_regs+28);
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err |= __put_user(regs->gp , sc->sc_regs+29);
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err |= __put_user(sp, sc->sc_regs+30);
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err |= __put_user(0, sc->sc_regs+31);
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for (i = 0; i < 31; i++)
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err |= __put_user(sw->fp[i], sc->sc_fpregs+i);
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err |= __put_user(0, sc->sc_fpregs+31);
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err |= __put_user(sw->fp[31], &sc->sc_fpcr);
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err |= __put_user(regs->trap_a0, &sc->sc_traparg_a0);
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err |= __put_user(regs->trap_a1, &sc->sc_traparg_a1);
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err |= __put_user(regs->trap_a2, &sc->sc_traparg_a2);
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return err;
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}
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static int
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setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
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{
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unsigned long oldsp, r26, err = 0;
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struct sigframe __user *frame;
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oldsp = rdusp();
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frame = get_sigframe(ksig, oldsp, sizeof(*frame));
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if (!access_ok(frame, sizeof(*frame)))
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return -EFAULT;
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err |= setup_sigcontext(&frame->sc, regs, set->sig[0], oldsp);
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if (err)
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return -EFAULT;
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/* Set up to return from userspace. If provided, use a stub
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already in userspace. */
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r26 = (unsigned long) ksig->ka.ka_restorer;
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if (!r26) {
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err |= __put_user(INSN_MOV_R30_R16, frame->retcode+0);
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err |= __put_user(INSN_LDI_R0+__NR_sigreturn, frame->retcode+1);
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err |= __put_user(INSN_CALLSYS, frame->retcode+2);
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imb();
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r26 = (unsigned long) frame->retcode;
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}
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/* Check that everything was written properly. */
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if (err)
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return err;
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/* "Return" to the handler */
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regs->r26 = r26;
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regs->r27 = regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
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regs->r16 = ksig->sig; /* a0: signal number */
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regs->r17 = 0; /* a1: exception code */
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regs->r18 = (unsigned long) &frame->sc; /* a2: sigcontext pointer */
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wrusp((unsigned long) frame);
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#if DEBUG_SIG
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printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
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current->comm, current->pid, frame, regs->pc, regs->r26);
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#endif
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return 0;
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}
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static int
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setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
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{
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unsigned long oldsp, r26, err = 0;
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struct rt_sigframe __user *frame;
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oldsp = rdusp();
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frame = get_sigframe(ksig, oldsp, sizeof(*frame));
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if (!access_ok(frame, sizeof(*frame)))
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return -EFAULT;
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err |= copy_siginfo_to_user(&frame->info, &ksig->info);
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/* Create the ucontext. */
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err |= __put_user(0, &frame->uc.uc_flags);
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err |= __put_user(0, &frame->uc.uc_link);
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err |= __put_user(set->sig[0], &frame->uc.uc_osf_sigmask);
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err |= __save_altstack(&frame->uc.uc_stack, oldsp);
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err |= setup_sigcontext(&frame->uc.uc_mcontext, regs,
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set->sig[0], oldsp);
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err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
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if (err)
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return -EFAULT;
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/* Set up to return from userspace. If provided, use a stub
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already in userspace. */
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r26 = (unsigned long) ksig->ka.ka_restorer;
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if (!r26) {
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err |= __put_user(INSN_MOV_R30_R16, frame->retcode+0);
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err |= __put_user(INSN_LDI_R0+__NR_rt_sigreturn,
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frame->retcode+1);
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err |= __put_user(INSN_CALLSYS, frame->retcode+2);
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imb();
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r26 = (unsigned long) frame->retcode;
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}
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if (err)
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return -EFAULT;
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/* "Return" to the handler */
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regs->r26 = r26;
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regs->r27 = regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
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regs->r16 = ksig->sig; /* a0: signal number */
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regs->r17 = (unsigned long) &frame->info; /* a1: siginfo pointer */
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regs->r18 = (unsigned long) &frame->uc; /* a2: ucontext pointer */
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wrusp((unsigned long) frame);
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#if DEBUG_SIG
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printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
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current->comm, current->pid, frame, regs->pc, regs->r26);
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#endif
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return 0;
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}
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/*
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* OK, we're invoking a handler.
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*/
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static inline void
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handle_signal(struct ksignal *ksig, struct pt_regs *regs)
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{
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sigset_t *oldset = sigmask_to_save();
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int ret;
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if (ksig->ka.sa.sa_flags & SA_SIGINFO)
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ret = setup_rt_frame(ksig, oldset, regs);
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else
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ret = setup_frame(ksig, oldset, regs);
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signal_setup_done(ret, ksig, 0);
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}
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static inline void
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syscall_restart(unsigned long r0, unsigned long r19,
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struct pt_regs *regs, struct k_sigaction *ka)
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{
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switch (regs->r0) {
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case ERESTARTSYS:
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if (!(ka->sa.sa_flags & SA_RESTART)) {
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case ERESTARTNOHAND:
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regs->r0 = EINTR;
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break;
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}
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/* fallthrough */
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case ERESTARTNOINTR:
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regs->r0 = r0; /* reset v0 and a3 and replay syscall */
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regs->r19 = r19;
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regs->pc -= 4;
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break;
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|
case ERESTART_RESTARTBLOCK:
|
|
regs->r0 = EINTR;
|
|
break;
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* 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.
|
|
*
|
|
* Note that we go through the signals twice: once to check the signals that
|
|
* the kernel can handle, and then we build all the user-level signal handling
|
|
* stack-frames in one go after that.
|
|
*
|
|
* "r0" and "r19" are the registers we need to restore for system call
|
|
* restart. "r0" is also used as an indicator whether we can restart at
|
|
* all (if we get here from anything but a syscall return, it will be 0)
|
|
*/
|
|
static void
|
|
do_signal(struct pt_regs *regs, unsigned long r0, unsigned long r19)
|
|
{
|
|
unsigned long single_stepping = ptrace_cancel_bpt(current);
|
|
struct ksignal ksig;
|
|
|
|
/* This lets the debugger run, ... */
|
|
if (get_signal(&ksig)) {
|
|
/* ... so re-check the single stepping. */
|
|
single_stepping |= ptrace_cancel_bpt(current);
|
|
/* Whee! Actually deliver the signal. */
|
|
if (r0)
|
|
syscall_restart(r0, r19, regs, &ksig.ka);
|
|
handle_signal(&ksig, regs);
|
|
} else {
|
|
single_stepping |= ptrace_cancel_bpt(current);
|
|
if (r0) {
|
|
switch (regs->r0) {
|
|
case ERESTARTNOHAND:
|
|
case ERESTARTSYS:
|
|
case ERESTARTNOINTR:
|
|
/* Reset v0 and a3 and replay syscall. */
|
|
regs->r0 = r0;
|
|
regs->r19 = r19;
|
|
regs->pc -= 4;
|
|
break;
|
|
case ERESTART_RESTARTBLOCK:
|
|
/* Set v0 to the restart_syscall and replay */
|
|
regs->r0 = __NR_restart_syscall;
|
|
regs->pc -= 4;
|
|
break;
|
|
}
|
|
}
|
|
restore_saved_sigmask();
|
|
}
|
|
if (single_stepping)
|
|
ptrace_set_bpt(current); /* re-set breakpoint */
|
|
}
|
|
|
|
void
|
|
do_work_pending(struct pt_regs *regs, unsigned long thread_flags,
|
|
unsigned long r0, unsigned long r19)
|
|
{
|
|
do {
|
|
if (thread_flags & _TIF_NEED_RESCHED) {
|
|
schedule();
|
|
} else {
|
|
local_irq_enable();
|
|
if (thread_flags & _TIF_SIGPENDING) {
|
|
do_signal(regs, r0, r19);
|
|
r0 = 0;
|
|
} else {
|
|
clear_thread_flag(TIF_NOTIFY_RESUME);
|
|
tracehook_notify_resume(regs);
|
|
}
|
|
}
|
|
local_irq_disable();
|
|
thread_flags = current_thread_info()->flags;
|
|
} while (thread_flags & _TIF_WORK_MASK);
|
|
}
|