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