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