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507 lines
13 KiB
507 lines
13 KiB
// 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/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(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); |
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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(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); |
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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(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(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. |
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*/ |
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restore_saved_sigmask(); |
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} |
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asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0, |
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unsigned long thread_info_flags) |
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{ |
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/* deal with pending signal delivery */ |
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if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) |
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do_signal(regs, save_r0); |
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if (thread_info_flags & _TIF_NOTIFY_RESUME) |
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tracehook_notify_resume(regs); |
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}
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