298 lines
6.3 KiB
C
298 lines
6.3 KiB
C
/*
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* Copyright (C) 2004-2006 Atmel Corporation
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*
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* Based on linux/arch/sh/kernel/signal.c
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* Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/errno.h>
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#include <linux/ptrace.h>
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#include <linux/unistd.h>
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#include <linux/tracehook.h>
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#include <asm/uaccess.h>
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#include <asm/ucontext.h>
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#include <asm/syscalls.h>
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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 long retcode;
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};
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static int
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restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
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{
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int err = 0;
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#define COPY(x) err |= __get_user(regs->x, &sc->x)
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COPY(sr);
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COPY(pc);
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COPY(lr);
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COPY(sp);
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COPY(r12);
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COPY(r11);
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COPY(r10);
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COPY(r9);
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COPY(r8);
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COPY(r7);
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COPY(r6);
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COPY(r5);
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COPY(r4);
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COPY(r3);
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COPY(r2);
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COPY(r1);
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COPY(r0);
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#undef COPY
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/*
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* Don't allow anyone to pretend they're running in supervisor
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* mode or something...
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*/
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err |= !valid_user_regs(regs);
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return err;
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}
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asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
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{
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struct rt_sigframe __user *frame;
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sigset_t set;
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/* Always make any pending restarted system calls return -EINTR */
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current_thread_info()->restart_block.fn = do_no_restart_syscall;
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frame = (struct rt_sigframe __user *)regs->sp;
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pr_debug("SIG return: frame = %p\n", frame);
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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))
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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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pr_debug("Context restored: pc = %08lx, lr = %08lx, sp = %08lx\n",
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regs->pc, regs->lr, regs->sp);
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return regs->r12;
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badframe:
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force_sig(SIGSEGV, current);
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return 0;
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}
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static int
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setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
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{
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int err = 0;
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#define COPY(x) err |= __put_user(regs->x, &sc->x)
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COPY(sr);
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COPY(pc);
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COPY(lr);
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COPY(sp);
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COPY(r12);
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COPY(r11);
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COPY(r10);
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COPY(r9);
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COPY(r8);
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COPY(r7);
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COPY(r6);
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COPY(r5);
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COPY(r4);
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COPY(r3);
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COPY(r2);
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COPY(r1);
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COPY(r0);
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#undef COPY
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return err;
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}
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static inline void __user *
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get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
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{
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unsigned long sp = regs->sp;
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if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
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sp = current->sas_ss_sp + current->sas_ss_size;
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return (void __user *)((sp - framesize) & ~3);
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}
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static int
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setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
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sigset_t *set, struct pt_regs *regs)
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{
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struct rt_sigframe __user *frame;
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int err = 0;
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frame = get_sigframe(ka, regs, sizeof(*frame));
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err = -EFAULT;
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if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
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goto out;
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/*
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* Set up the return code:
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*
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* mov r8, __NR_rt_sigreturn
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* scall
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*
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* Note: This will blow up since we're using a non-executable
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* stack. Better use SA_RESTORER.
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*/
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#if __NR_rt_sigreturn > 127
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# error __NR_rt_sigreturn must be < 127 to fit in a short mov
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#endif
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err = __put_user(0x3008d733 | (__NR_rt_sigreturn << 20),
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&frame->retcode);
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err |= copy_siginfo_to_user(&frame->info, info);
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/* Set up 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->sp);
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err |= setup_sigcontext(&frame->uc.uc_mcontext, regs);
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err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
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if (err)
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goto out;
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regs->r12 = sig;
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regs->r11 = (unsigned long) &frame->info;
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regs->r10 = (unsigned long) &frame->uc;
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regs->sp = (unsigned long) frame;
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if (ka->sa.sa_flags & SA_RESTORER)
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regs->lr = (unsigned long)ka->sa.sa_restorer;
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else {
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printk(KERN_NOTICE "[%s:%d] did not set SA_RESTORER\n",
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current->comm, current->pid);
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regs->lr = (unsigned long) &frame->retcode;
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}
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pr_debug("SIG deliver [%s:%d]: sig=%d sp=0x%lx pc=0x%lx->0x%p lr=0x%lx\n",
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current->comm, current->pid, sig, regs->sp,
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regs->pc, ka->sa.sa_handler, regs->lr);
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regs->pc = (unsigned long) ka->sa.sa_handler;
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out:
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return err;
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}
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static inline void setup_syscall_restart(struct pt_regs *regs)
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{
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if (regs->r12 == -ERESTART_RESTARTBLOCK)
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regs->r8 = __NR_restart_syscall;
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else
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regs->r12 = regs->r12_orig;
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regs->pc -= 2;
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}
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static inline void
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handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
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struct pt_regs *regs, int syscall)
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{
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int ret;
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/*
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* Set up the stack frame
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*/
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ret = setup_rt_frame(sig, ka, info, sigmask_to_save(), regs);
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/*
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* Check that the resulting registers are sane
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*/
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ret |= !valid_user_regs(regs);
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/*
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* Block the signal if we were successful.
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*/
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if (ret != 0)
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force_sigsegv(sig, current);
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else
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signal_delivered(sig, info, ka, regs, 0);
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}
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/*
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* Note that 'init' is a special process: it doesn't get signals it
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* doesn't want to handle. Thus you cannot kill init even with a
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* SIGKILL even by mistake.
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*/
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static void do_signal(struct pt_regs *regs, int syscall)
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{
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siginfo_t info;
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int signr;
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struct k_sigaction ka;
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/*
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* We want the common case to go fast, which is why we may in
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* certain cases get here from kernel mode. Just return
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* without doing anything if so.
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*/
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if (!user_mode(regs))
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return;
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signr = get_signal_to_deliver(&info, &ka, regs, NULL);
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if (syscall) {
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switch (regs->r12) {
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case -ERESTART_RESTARTBLOCK:
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case -ERESTARTNOHAND:
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if (signr > 0) {
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regs->r12 = -EINTR;
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break;
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}
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/* fall through */
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case -ERESTARTSYS:
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if (signr > 0 && !(ka.sa.sa_flags & SA_RESTART)) {
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regs->r12 = -EINTR;
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break;
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}
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/* fall through */
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case -ERESTARTNOINTR:
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setup_syscall_restart(regs);
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}
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}
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if (signr == 0) {
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/* No signal to deliver -- put the saved sigmask back */
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restore_saved_sigmask();
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return;
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}
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handle_signal(signr, &ka, &info, regs, syscall);
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}
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asmlinkage void do_notify_resume(struct pt_regs *regs, struct thread_info *ti)
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{
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int syscall = 0;
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if ((sysreg_read(SR) & MODE_MASK) == MODE_SUPERVISOR)
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syscall = 1;
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if (ti->flags & _TIF_SIGPENDING)
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do_signal(regs, syscall);
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if (ti->flags & _TIF_NOTIFY_RESUME) {
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clear_thread_flag(TIF_NOTIFY_RESUME);
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tracehook_notify_resume(regs);
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}
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}
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