511 lines
13 KiB
C
511 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/arch/sh/kernel/signal.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
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*
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* SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
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*
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*/
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#include <linux/sched.h>
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#include <linux/sched/task_stack.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/stddef.h>
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#include <linux/tty.h>
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#include <linux/elf.h>
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#include <linux/personality.h>
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#include <linux/binfmts.h>
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#include <linux/io.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/pgtable.h>
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#include <asm/cacheflush.h>
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#include <asm/syscalls.h>
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#include <asm/fpu.h>
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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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* The following define adds a 64 byte gap between the signal
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* stack frame and previous contents of the stack. This allows
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* frame unwinding in a function epilogue but only if a frame
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* pointer is used in the function. This is necessary because
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* current gcc compilers (<4.3) do not generate unwind info on
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* SH for function epilogues.
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*/
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#define UNWINDGUARD 64
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/*
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* Do a signal return; undo the signal stack.
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*/
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#define MOVW(n) (0x9300|((n)-2)) /* Move mem word at PC+n to R3 */
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#if defined(CONFIG_CPU_SH2)
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#define TRAP_NOARG 0xc320 /* Syscall w/no args (NR in R3) */
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#else
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#define TRAP_NOARG 0xc310 /* Syscall w/no args (NR in R3) */
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#endif
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#define OR_R0_R0 0x200b /* or r0,r0 (insert to avoid hardware bug) */
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struct sigframe
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{
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struct sigcontext sc;
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unsigned long extramask[_NSIG_WORDS-1];
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u16 retcode[8];
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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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u16 retcode[8];
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};
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#ifdef CONFIG_SH_FPU
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static inline int restore_sigcontext_fpu(struct sigcontext __user *sc)
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{
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struct task_struct *tsk = current;
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if (!(boot_cpu_data.flags & CPU_HAS_FPU))
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return 0;
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set_used_math();
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return __copy_from_user(&tsk->thread.xstate->hardfpu, &sc->sc_fpregs[0],
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sizeof(long)*(16*2+2));
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}
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static inline int save_sigcontext_fpu(struct sigcontext __user *sc,
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struct pt_regs *regs)
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{
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struct task_struct *tsk = current;
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if (!(boot_cpu_data.flags & CPU_HAS_FPU))
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return 0;
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if (!used_math())
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return __put_user(0, &sc->sc_ownedfp);
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if (__put_user(1, &sc->sc_ownedfp))
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return -EFAULT;
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/* This will cause a "finit" to be triggered by the next
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attempted FPU operation by the 'current' process.
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*/
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clear_used_math();
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unlazy_fpu(tsk, regs);
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return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.xstate->hardfpu,
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sizeof(long)*(16*2+2));
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}
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#endif /* CONFIG_SH_FPU */
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static int
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restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p)
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{
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unsigned int err = 0;
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#define COPY(x) err |= __get_user(regs->x, &sc->sc_##x)
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COPY(regs[1]);
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COPY(regs[2]); COPY(regs[3]);
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COPY(regs[4]); COPY(regs[5]);
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COPY(regs[6]); COPY(regs[7]);
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COPY(regs[8]); COPY(regs[9]);
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COPY(regs[10]); COPY(regs[11]);
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COPY(regs[12]); COPY(regs[13]);
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COPY(regs[14]); COPY(regs[15]);
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COPY(gbr); COPY(mach);
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COPY(macl); COPY(pr);
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COPY(sr); COPY(pc);
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#undef COPY
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#ifdef CONFIG_SH_FPU
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if (boot_cpu_data.flags & CPU_HAS_FPU) {
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int owned_fp;
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struct task_struct *tsk = current;
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regs->sr |= SR_FD; /* Release FPU */
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clear_fpu(tsk, regs);
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clear_used_math();
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err |= __get_user (owned_fp, &sc->sc_ownedfp);
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if (owned_fp)
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err |= restore_sigcontext_fpu(sc);
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}
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#endif
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regs->tra = -1; /* disable syscall checks */
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err |= __get_user(*r0_p, &sc->sc_regs[0]);
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return err;
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}
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asmlinkage int sys_sigreturn(void)
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{
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struct pt_regs *regs = current_pt_regs();
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struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15];
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sigset_t set;
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int r0;
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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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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.oldmask)
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|| (_NSIG_WORDS > 1
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&& __copy_from_user(&set.sig[1], &frame->extramask,
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sizeof(frame->extramask))))
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goto badframe;
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set_current_blocked(&set);
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if (restore_sigcontext(regs, &frame->sc, &r0))
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goto badframe;
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return r0;
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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 pt_regs *regs = current_pt_regs();
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struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15];
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sigset_t set;
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int r0;
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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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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(regs, &frame->uc.uc_mcontext, &r0))
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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 r0;
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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
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setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
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unsigned long mask)
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{
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int err = 0;
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#define COPY(x) err |= __put_user(regs->x, &sc->sc_##x)
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COPY(regs[0]); COPY(regs[1]);
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COPY(regs[2]); COPY(regs[3]);
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COPY(regs[4]); COPY(regs[5]);
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COPY(regs[6]); COPY(regs[7]);
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COPY(regs[8]); COPY(regs[9]);
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COPY(regs[10]); COPY(regs[11]);
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COPY(regs[12]); COPY(regs[13]);
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COPY(regs[14]); COPY(regs[15]);
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COPY(gbr); COPY(mach);
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COPY(macl); COPY(pr);
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COPY(sr); COPY(pc);
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#undef COPY
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#ifdef CONFIG_SH_FPU
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err |= save_sigcontext_fpu(sc, regs);
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#endif
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/* non-iBCS2 extensions.. */
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err |= __put_user(mask, &sc->oldmask);
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return err;
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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 *
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get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
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{
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if (ka->sa.sa_flags & SA_ONSTACK) {
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if (sas_ss_flags(sp) == 0)
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sp = current->sas_ss_sp + current->sas_ss_size;
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}
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return (void __user *)((sp - (frame_size+UNWINDGUARD)) & -8ul);
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}
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/* These symbols are defined with the addresses in the vsyscall page.
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See vsyscall-trapa.S. */
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extern void __kernel_sigreturn(void);
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extern void __kernel_rt_sigreturn(void);
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static int setup_frame(struct ksignal *ksig, sigset_t *set,
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struct pt_regs *regs)
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{
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struct sigframe __user *frame;
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int err = 0, sig = ksig->sig;
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frame = get_sigframe(&ksig->ka, regs->regs[15], sizeof(*frame));
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if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
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return -EFAULT;
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err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
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if (_NSIG_WORDS > 1)
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err |= __copy_to_user(frame->extramask, &set->sig[1],
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sizeof(frame->extramask));
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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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regs->pr = (unsigned long) ksig->ka.sa.sa_restorer;
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#ifdef CONFIG_VSYSCALL
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} else if (likely(current->mm->context.vdso)) {
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regs->pr = VDSO_SYM(&__kernel_sigreturn);
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#endif
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} else {
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/* Generate return code (system call to sigreturn) */
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err |= __put_user(MOVW(7), &frame->retcode[0]);
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err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
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err |= __put_user(OR_R0_R0, &frame->retcode[2]);
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err |= __put_user(OR_R0_R0, &frame->retcode[3]);
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err |= __put_user(OR_R0_R0, &frame->retcode[4]);
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err |= __put_user(OR_R0_R0, &frame->retcode[5]);
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err |= __put_user(OR_R0_R0, &frame->retcode[6]);
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err |= __put_user((__NR_sigreturn), &frame->retcode[7]);
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regs->pr = (unsigned long) frame->retcode;
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flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode));
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}
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if (err)
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return -EFAULT;
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/* Set up registers for signal handler */
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regs->regs[15] = (unsigned long) frame;
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regs->regs[4] = sig; /* Arg for signal handler */
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regs->regs[5] = 0;
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regs->regs[6] = (unsigned long) &frame->sc;
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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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err |= __get_user(regs->pc, &funcptr->text);
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err |= __get_user(regs->regs[12], &funcptr->GOT);
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} else
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regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
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if (err)
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return -EFAULT;
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pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
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current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);
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return 0;
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}
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static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
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struct pt_regs *regs)
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{
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struct rt_sigframe __user *frame;
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int err = 0, sig = ksig->sig;
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frame = get_sigframe(&ksig->ka, regs->regs[15], sizeof(*frame));
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if (!access_ok(VERIFY_WRITE, 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(NULL, &frame->uc.uc_link);
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err |= __save_altstack(&frame->uc.uc_stack, regs->regs[15]);
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err |= setup_sigcontext(&frame->uc.uc_mcontext,
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regs, set->sig[0]);
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err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
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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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regs->pr = (unsigned long) ksig->ka.sa.sa_restorer;
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#ifdef CONFIG_VSYSCALL
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} else if (likely(current->mm->context.vdso)) {
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regs->pr = VDSO_SYM(&__kernel_rt_sigreturn);
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#endif
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} else {
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/* Generate return code (system call to rt_sigreturn) */
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err |= __put_user(MOVW(7), &frame->retcode[0]);
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err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
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err |= __put_user(OR_R0_R0, &frame->retcode[2]);
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err |= __put_user(OR_R0_R0, &frame->retcode[3]);
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err |= __put_user(OR_R0_R0, &frame->retcode[4]);
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err |= __put_user(OR_R0_R0, &frame->retcode[5]);
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err |= __put_user(OR_R0_R0, &frame->retcode[6]);
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err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]);
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regs->pr = (unsigned long) frame->retcode;
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flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode));
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}
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if (err)
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return -EFAULT;
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/* Set up registers for signal handler */
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regs->regs[15] = (unsigned long) frame;
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regs->regs[4] = sig; /* Arg for signal handler */
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regs->regs[5] = (unsigned long) &frame->info;
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regs->regs[6] = (unsigned long) &frame->uc;
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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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err |= __get_user(regs->pc, &funcptr->text);
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err |= __get_user(regs->regs[12], &funcptr->GOT);
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} else
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regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
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if (err)
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return -EFAULT;
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pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
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current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);
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return 0;
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}
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static inline void
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handle_syscall_restart(unsigned long save_r0, struct pt_regs *regs,
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struct sigaction *sa)
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{
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/* If we're not from a syscall, bail out */
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if (regs->tra < 0)
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return;
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/* check for system call restart.. */
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switch (regs->regs[0]) {
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case -ERESTART_RESTARTBLOCK:
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case -ERESTARTNOHAND:
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no_system_call_restart:
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regs->regs[0] = -EINTR;
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break;
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case -ERESTARTSYS:
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if (!(sa->sa_flags & SA_RESTART))
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goto no_system_call_restart;
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/* fallthrough */
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case -ERESTARTNOINTR:
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regs->regs[0] = save_r0;
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regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
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break;
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}
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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
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handle_signal(struct ksignal *ksig, struct pt_regs *regs, unsigned int save_r0)
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{
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sigset_t *oldset = sigmask_to_save();
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int ret;
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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, 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, test_thread_flag(TIF_SINGLESTEP));
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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 that
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* the kernel can handle, and then we build all the user-level signal handling
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* stack-frames in one go after that.
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*/
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static void do_signal(struct pt_regs *regs, unsigned int save_r0)
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{
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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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if (get_signal(&ksig)) {
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handle_syscall_restart(save_r0, regs, &ksig.ka.sa);
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/* Whee! Actually deliver the signal. */
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handle_signal(&ksig, regs, save_r0);
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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 (regs->tra >= 0) {
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/* Restart the system call - no handlers present */
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if (regs->regs[0] == -ERESTARTNOHAND ||
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regs->regs[0] == -ERESTARTSYS ||
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regs->regs[0] == -ERESTARTNOINTR) {
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regs->regs[0] = save_r0;
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regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
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} else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) {
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regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
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regs->regs[3] = __NR_restart_syscall;
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}
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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.
|
|
*/
|
|
restore_saved_sigmask();
|
|
}
|
|
|
|
asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0,
|
|
unsigned long thread_info_flags)
|
|
{
|
|
/* deal with pending signal delivery */
|
|
if (thread_info_flags & _TIF_SIGPENDING)
|
|
do_signal(regs, save_r0);
|
|
|
|
if (thread_info_flags & _TIF_NOTIFY_RESUME) {
|
|
clear_thread_flag(TIF_NOTIFY_RESUME);
|
|
tracehook_notify_resume(regs);
|
|
}
|
|
}
|