427 lines
10 KiB
C
427 lines
10 KiB
C
/* signal.c: FRV specific bits of signal handling
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*
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* Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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* - Derived from arch/m68k/kernel/signal.c
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/smp.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/personality.h>
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#include <linux/tracehook.h>
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#include <asm/ucontext.h>
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#include <linux/uaccess.h>
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#include <asm/cacheflush.h>
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#define DEBUG_SIG 0
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struct fdpic_func_descriptor {
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unsigned long text;
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unsigned long GOT;
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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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struct sigframe
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{
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__sigrestore_t pretcode;
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int sig;
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struct sigcontext sc;
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unsigned long extramask[_NSIG_WORDS-1];
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uint32_t retcode[2];
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};
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struct rt_sigframe
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{
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__sigrestore_t pretcode;
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int sig;
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struct siginfo __user *pinfo;
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void __user *puc;
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struct siginfo info;
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struct ucontext uc;
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uint32_t retcode[2];
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};
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static int restore_sigcontext(struct sigcontext __user *sc, int *_gr8)
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{
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struct user_context *user = current->thread.user;
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unsigned long tbr, psr;
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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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tbr = user->i.tbr;
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psr = user->i.psr;
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if (copy_from_user(user, &sc->sc_context, sizeof(sc->sc_context)))
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goto badframe;
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user->i.tbr = tbr;
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user->i.psr = psr;
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restore_user_regs(user);
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user->i.syscallno = -1; /* disable syscall checks */
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*_gr8 = user->i.gr[8];
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return 0;
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badframe:
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return 1;
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}
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asmlinkage int sys_sigreturn(void)
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{
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struct sigframe __user *frame = (struct sigframe __user *) __frame->sp;
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sigset_t set;
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int gr8;
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if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
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goto badframe;
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if (__get_user(set.sig[0], &frame->sc.sc_oldmask))
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goto badframe;
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if (_NSIG_WORDS > 1 &&
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__copy_from_user(&set.sig[1], &frame->extramask, sizeof(frame->extramask)))
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goto badframe;
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set_current_blocked(&set);
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if (restore_sigcontext(&frame->sc, &gr8))
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goto badframe;
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return gr8;
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badframe:
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force_sig(SIGSEGV, current);
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return 0;
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}
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asmlinkage int sys_rt_sigreturn(void)
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{
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struct rt_sigframe __user *frame = (struct rt_sigframe __user *) __frame->sp;
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sigset_t set;
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int gr8;
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if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
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goto badframe;
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if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
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goto badframe;
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set_current_blocked(&set);
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if (restore_sigcontext(&frame->uc.uc_mcontext, &gr8))
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goto badframe;
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if (restore_altstack(&frame->uc.uc_stack))
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goto badframe;
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return gr8;
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badframe:
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force_sig(SIGSEGV, current);
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return 0;
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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 int setup_sigcontext(struct sigcontext __user *sc, unsigned long mask)
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{
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save_user_regs(current->thread.user);
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if (copy_to_user(&sc->sc_context, current->thread.user, sizeof(sc->sc_context)) != 0)
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goto badframe;
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/* non-iBCS2 extensions.. */
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if (__put_user(mask, &sc->sc_oldmask) < 0)
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goto badframe;
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return 0;
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badframe:
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return 1;
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}
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/*****************************************************************************/
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/*
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* Determine which stack to use..
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*/
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static inline void __user *get_sigframe(struct ksignal *ksig,
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size_t frame_size)
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{
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unsigned long sp = sigsp(__frame->sp, ksig);
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return (void __user *) ((sp - frame_size) & ~7UL);
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} /* end get_sigframe() */
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/*****************************************************************************/
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/*
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*
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*/
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static int setup_frame(struct ksignal *ksig, sigset_t *set)
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{
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struct sigframe __user *frame;
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int sig = ksig->sig;
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frame = get_sigframe(ksig, sizeof(*frame));
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if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
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return -EFAULT;
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if (__put_user(sig, &frame->sig) < 0)
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return -EFAULT;
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if (setup_sigcontext(&frame->sc, set->sig[0]))
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return -EFAULT;
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if (_NSIG_WORDS > 1) {
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if (__copy_to_user(frame->extramask, &set->sig[1],
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sizeof(frame->extramask)))
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return -EFAULT;
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}
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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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if (ksig->ka.sa.sa_flags & SA_RESTORER) {
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if (__put_user(ksig->ka.sa.sa_restorer, &frame->pretcode) < 0)
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return -EFAULT;
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}
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else {
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/* Set up the following code on the stack:
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* setlos #__NR_sigreturn,gr7
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* tira gr0,0
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*/
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if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
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__put_user(0x8efc0000|__NR_sigreturn, &frame->retcode[0]) ||
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__put_user(0xc0700000, &frame->retcode[1]))
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return -EFAULT;
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flush_icache_range((unsigned long) frame->retcode,
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(unsigned long) (frame->retcode + 2));
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}
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/* Set up registers for the signal handler */
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if (current->personality & FDPIC_FUNCPTRS) {
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struct fdpic_func_descriptor __user *funcptr =
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(struct fdpic_func_descriptor __user *) ksig->ka.sa.sa_handler;
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struct fdpic_func_descriptor desc;
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if (copy_from_user(&desc, funcptr, sizeof(desc)))
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return -EFAULT;
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__frame->pc = desc.text;
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__frame->gr15 = desc.GOT;
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} else {
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__frame->pc = (unsigned long) ksig->ka.sa.sa_handler;
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__frame->gr15 = 0;
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}
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__frame->sp = (unsigned long) frame;
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__frame->lr = (unsigned long) &frame->retcode;
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__frame->gr8 = sig;
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#if DEBUG_SIG
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printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
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sig, current->comm, current->pid, frame, __frame->pc,
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frame->pretcode);
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#endif
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return 0;
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} /* end setup_frame() */
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/*****************************************************************************/
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/*
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*
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*/
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static int setup_rt_frame(struct ksignal *ksig, sigset_t *set)
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{
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struct rt_sigframe __user *frame;
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int sig = ksig->sig;
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frame = get_sigframe(ksig, sizeof(*frame));
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if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
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return -EFAULT;
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if (__put_user(sig, &frame->sig) ||
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__put_user(&frame->info, &frame->pinfo) ||
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__put_user(&frame->uc, &frame->puc))
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return -EFAULT;
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if (copy_siginfo_to_user(&frame->info, &ksig->info))
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return -EFAULT;
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/* Create the ucontext. */
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if (__put_user(0, &frame->uc.uc_flags) ||
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__put_user(NULL, &frame->uc.uc_link) ||
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__save_altstack(&frame->uc.uc_stack, __frame->sp))
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return -EFAULT;
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if (setup_sigcontext(&frame->uc.uc_mcontext, set->sig[0]))
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return -EFAULT;
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if (__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
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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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if (ksig->ka.sa.sa_flags & SA_RESTORER) {
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if (__put_user(ksig->ka.sa.sa_restorer, &frame->pretcode))
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return -EFAULT;
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}
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else {
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/* Set up the following code on the stack:
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* setlos #__NR_sigreturn,gr7
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* tira gr0,0
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*/
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if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) ||
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__put_user(0x8efc0000|__NR_rt_sigreturn, &frame->retcode[0]) ||
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__put_user(0xc0700000, &frame->retcode[1]))
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return -EFAULT;
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flush_icache_range((unsigned long) frame->retcode,
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(unsigned long) (frame->retcode + 2));
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}
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/* Set up registers for signal handler */
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if (current->personality & FDPIC_FUNCPTRS) {
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struct fdpic_func_descriptor __user *funcptr =
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(struct fdpic_func_descriptor __user *) ksig->ka.sa.sa_handler;
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struct fdpic_func_descriptor desc;
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if (copy_from_user(&desc, funcptr, sizeof(desc)))
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return -EFAULT;
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__frame->pc = desc.text;
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__frame->gr15 = desc.GOT;
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} else {
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__frame->pc = (unsigned long) ksig->ka.sa.sa_handler;
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__frame->gr15 = 0;
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}
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__frame->sp = (unsigned long) frame;
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__frame->lr = (unsigned long) &frame->retcode;
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__frame->gr8 = sig;
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__frame->gr9 = (unsigned long) &frame->info;
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#if DEBUG_SIG
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printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
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sig, current->comm, current->pid, frame, __frame->pc,
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frame->pretcode);
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#endif
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return 0;
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} /* end setup_rt_frame() */
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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 void handle_signal(struct ksignal *ksig)
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{
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sigset_t *oldset = sigmask_to_save();
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int ret;
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/* Are we from a system call? */
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if (__frame->syscallno != -1) {
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/* If so, check system call restarting.. */
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switch (__frame->gr8) {
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case -ERESTART_RESTARTBLOCK:
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case -ERESTARTNOHAND:
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__frame->gr8 = -EINTR;
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break;
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case -ERESTARTSYS:
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if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
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__frame->gr8 = -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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__frame->gr8 = __frame->orig_gr8;
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__frame->pc -= 4;
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}
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__frame->syscallno = -1;
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}
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/* Set up the stack frame */
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if (ksig->ka.sa.sa_flags & SA_SIGINFO)
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ret = setup_rt_frame(ksig, oldset);
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else
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ret = setup_frame(ksig, oldset);
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signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
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} /* end handle_signal() */
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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
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* want to handle. Thus you cannot kill init even with a SIGKILL even by
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* mistake.
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*/
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static void do_signal(void)
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{
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struct ksignal ksig;
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if (get_signal(&ksig)) {
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handle_signal(&ksig);
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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 (__frame->syscallno != -1) {
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/* Restart the system call - no handlers present */
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switch (__frame->gr8) {
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case -ERESTARTNOHAND:
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case -ERESTARTSYS:
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case -ERESTARTNOINTR:
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__frame->gr8 = __frame->orig_gr8;
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__frame->pc -= 4;
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break;
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case -ERESTART_RESTARTBLOCK:
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__frame->gr7 = __NR_restart_syscall;
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__frame->pc -= 4;
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break;
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}
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__frame->syscallno = -1;
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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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} /* end do_signal() */
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/*****************************************************************************/
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/*
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* notification of userspace execution resumption
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* - triggered by the TIF_WORK_MASK flags
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*/
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asmlinkage void do_notify_resume(__u32 thread_info_flags)
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{
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/* pending single-step? */
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if (thread_info_flags & _TIF_SINGLESTEP)
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clear_thread_flag(TIF_SINGLESTEP);
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/* deal with pending signal delivery */
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if (thread_info_flags & _TIF_SIGPENDING)
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do_signal();
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/* deal with notification on about to resume userspace execution */
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if (thread_info_flags & _TIF_NOTIFY_RESUME) {
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clear_thread_flag(TIF_NOTIFY_RESUME);
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tracehook_notify_resume(__frame);
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}
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} /* end do_notify_resume() */
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