348 lines
8.3 KiB
C
348 lines
8.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/kernel.h>
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#include <linux/signal.h>
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#include <linux/syscalls.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/stddef.h>
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#include <linux/highuid.h>
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#include <linux/personality.h>
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#include <linux/tty.h>
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#include <linux/binfmts.h>
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#include <linux/tracehook.h>
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#include <linux/freezer.h>
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#include <linux/uaccess.h>
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#include <asm/setup.h>
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#include <asm/pgtable.h>
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#include <asm/traps.h>
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#include <asm/ucontext.h>
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#include <asm/vdso.h>
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#include <abi/regdef.h>
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#ifdef CONFIG_CPU_HAS_FPU
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#include <abi/fpu.h>
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static int restore_fpu_state(struct sigcontext *sc)
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{
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int err = 0;
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struct user_fp user_fp;
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err = copy_from_user(&user_fp, &sc->sc_user_fp, sizeof(user_fp));
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restore_from_user_fp(&user_fp);
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return err;
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}
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static int save_fpu_state(struct sigcontext *sc)
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{
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struct user_fp user_fp;
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save_to_user_fp(&user_fp);
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return copy_to_user(&sc->sc_user_fp, &user_fp, sizeof(user_fp));
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}
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#else
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static inline int restore_fpu_state(struct sigcontext *sc) { return 0; }
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static inline int save_fpu_state(struct sigcontext *sc) { return 0; }
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#endif
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struct rt_sigframe {
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int sig;
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struct siginfo *pinfo;
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void *puc;
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struct siginfo info;
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struct ucontext uc;
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};
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static int
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restore_sigframe(struct pt_regs *regs,
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struct sigcontext *sc, int *pr2)
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{
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int err = 0;
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/* Always make any pending restarted system calls return -EINTR */
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current_thread_info()->task->restart_block.fn = do_no_restart_syscall;
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err |= copy_from_user(regs, &sc->sc_pt_regs, sizeof(struct pt_regs));
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err |= restore_fpu_state(sc);
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*pr2 = regs->a0;
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return err;
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}
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asmlinkage int
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do_rt_sigreturn(void)
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{
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sigset_t set;
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int a0;
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struct pt_regs *regs = current_pt_regs();
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struct rt_sigframe *frame = (struct rt_sigframe *)(regs->usp);
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if (verify_area(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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sigdelsetmask(&set, (sigmask(SIGKILL) | sigmask(SIGSTOP)));
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spin_lock_irq(¤t->sighand->siglock);
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current->blocked = set;
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recalc_sigpending();
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spin_unlock_irq(¤t->sighand->siglock);
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if (restore_sigframe(regs, &frame->uc.uc_mcontext, &a0))
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goto badframe;
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return a0;
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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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static int setup_sigframe(struct sigcontext *sc, struct pt_regs *regs)
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{
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int err = 0;
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err |= copy_to_user(&sc->sc_pt_regs, regs, sizeof(struct pt_regs));
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err |= save_fpu_state(sc);
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return err;
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}
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static inline void *
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get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
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{
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unsigned long usp;
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/* Default to using normal stack. */
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usp = regs->usp;
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/* This is the X/Open sanctioned signal stack switching. */
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if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(usp)) {
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if (!on_sig_stack(usp))
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usp = current->sas_ss_sp + current->sas_ss_size;
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}
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return (void *)((usp - frame_size) & -8UL);
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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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struct rt_sigframe *frame;
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int err = 0;
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struct csky_vdso *vdso = current->mm->context.vdso;
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frame = get_sigframe(&ksig->ka, regs, sizeof(*frame));
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if (!frame)
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return 1;
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err |= __put_user(ksig->sig, &frame->sig);
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err |= __put_user(&frame->info, &frame->pinfo);
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err |= __put_user(&frame->uc, &frame->puc);
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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((void *)current->sas_ss_sp,
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&frame->uc.uc_stack.ss_sp);
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err |= __put_user(sas_ss_flags(regs->usp),
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&frame->uc.uc_stack.ss_flags);
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err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
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err |= setup_sigframe(&frame->uc.uc_mcontext, regs);
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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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goto give_sigsegv;
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/* Set up registers for signal handler */
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regs->usp = (unsigned long)frame;
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regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
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regs->lr = (unsigned long)vdso->rt_signal_retcode;
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adjust_stack:
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regs->a0 = ksig->sig; /* first arg is signo */
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regs->a1 = (unsigned long)(&(frame->info));
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regs->a2 = (unsigned long)(&(frame->uc));
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return err;
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give_sigsegv:
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if (ksig->sig == SIGSEGV)
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ksig->ka.sa.sa_handler = SIG_DFL;
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force_sig(SIGSEGV, current);
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goto adjust_stack;
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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 int
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handle_signal(struct ksignal *ksig, struct pt_regs *regs)
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{
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int ret;
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sigset_t *oldset = sigmask_to_save();
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/*
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* set up the stack frame, regardless of SA_SIGINFO,
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* and pass info anyway.
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*/
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ret = setup_rt_frame(ksig, oldset, regs);
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if (ret != 0) {
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force_sigsegv(ksig->sig, current);
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return ret;
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}
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/* Block the signal if we were successful. */
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spin_lock_irq(¤t->sighand->siglock);
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sigorsets(¤t->blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
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if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
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sigaddset(¤t->blocked, ksig->sig);
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recalc_sigpending();
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spin_unlock_irq(¤t->sighand->siglock);
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return 0;
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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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* Note that we go through the signals twice: once to check the signals
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* that the kernel can handle, and then we build all the user-level signal
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* handling stack-frames in one go after that.
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*/
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static void do_signal(struct pt_regs *regs, int syscall)
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{
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unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
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struct ksignal ksig;
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/*
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* We want the common case to go fast, which
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* is why we may in certain cases get here from
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* kernel mode. Just return without doing anything
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* if so.
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*/
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if (!user_mode(regs))
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return;
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current->thread.esp0 = (unsigned long)regs;
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/*
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* If we were from a system call, check for system call restarting...
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*/
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if (syscall) {
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continue_addr = regs->pc;
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#if defined(__CSKYABIV2__)
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restart_addr = continue_addr - 4;
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#else
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restart_addr = continue_addr - 2;
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#endif
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retval = regs->a0;
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/*
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* Prepare for system call restart. We do this here so that a
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* debugger will see the already changed.
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*/
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switch (retval) {
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case -ERESTARTNOHAND:
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case -ERESTARTSYS:
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case -ERESTARTNOINTR:
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regs->a0 = regs->orig_a0;
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regs->pc = restart_addr;
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break;
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case -ERESTART_RESTARTBLOCK:
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regs->a0 = -EINTR;
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break;
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}
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}
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if (try_to_freeze())
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goto no_signal;
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/*
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* Get the signal to deliver. When running under ptrace, at this
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* point the debugger may change all our registers ...
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*/
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if (get_signal(&ksig)) {
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/*
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* Depending on the signal settings we may need to revert the
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* decision to restart the system call. But skip this if a
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* debugger has chosen to restart at a different PC.
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*/
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if (regs->pc == restart_addr) {
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if (retval == -ERESTARTNOHAND ||
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(retval == -ERESTARTSYS &&
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!(ksig.ka.sa.sa_flags & SA_RESTART))) {
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regs->a0 = -EINTR;
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regs->pc = continue_addr;
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}
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}
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/* Whee! Actually deliver the signal. */
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if (handle_signal(&ksig, regs) == 0) {
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/*
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* A signal was successfully delivered; the saved
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* sigmask will have been stored in the signal frame,
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* and will be restored by sigreturn, so we can simply
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* clear the TIF_RESTORE_SIGMASK flag.
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*/
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if (test_thread_flag(TIF_RESTORE_SIGMASK))
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clear_thread_flag(TIF_RESTORE_SIGMASK);
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}
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return;
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}
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no_signal:
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if (syscall) {
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/*
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* Handle restarting a different system call. As above,
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* if a debugger has chosen to restart at a different PC,
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* ignore the restart.
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*/
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if (retval == -ERESTART_RESTARTBLOCK
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&& regs->pc == continue_addr) {
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#if defined(__CSKYABIV2__)
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regs->regs[3] = __NR_restart_syscall;
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regs->pc -= 4;
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#else
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regs->regs[9] = __NR_restart_syscall;
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regs->pc -= 2;
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#endif
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}
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/*
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* If there's no signal to deliver, we just put the saved
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* sigmask back.
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*/
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if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
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clear_thread_flag(TIF_RESTORE_SIGMASK);
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sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
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}
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}
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}
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asmlinkage void
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do_notify_resume(unsigned int thread_flags, struct pt_regs *regs, int syscall)
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{
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if (thread_flags & _TIF_SIGPENDING)
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do_signal(regs, syscall);
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if (thread_flags & _TIF_NOTIFY_RESUME) {
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clear_thread_flag(TIF_NOTIFY_RESUME);
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tracehook_notify_resume(regs);
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}
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}
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