/* signal.c: FRV specific bits of signal handling * * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * - Derived from arch/m68k/kernel/signal.c * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include <linux/sched.h> #include <linux/mm.h> #include <linux/smp.h> #include <linux/kernel.h> #include <linux/signal.h> #include <linux/errno.h> #include <linux/wait.h> #include <linux/ptrace.h> #include <linux/unistd.h> #include <linux/personality.h> #include <linux/tracehook.h> #include <asm/ucontext.h> #include <linux/uaccess.h> #include <asm/cacheflush.h> #define DEBUG_SIG 0 struct fdpic_func_descriptor { unsigned long text; unsigned long GOT; }; /* * Do a signal return; undo the signal stack. */ struct sigframe { __sigrestore_t pretcode; int sig; struct sigcontext sc; unsigned long extramask[_NSIG_WORDS-1]; uint32_t retcode[2]; }; struct rt_sigframe { __sigrestore_t pretcode; int sig; struct siginfo __user *pinfo; void __user *puc; struct siginfo info; struct ucontext uc; uint32_t retcode[2]; }; static int restore_sigcontext(struct sigcontext __user *sc, int *_gr8) { struct user_context *user = current->thread.user; unsigned long tbr, psr; /* Always make any pending restarted system calls return -EINTR */ current->restart_block.fn = do_no_restart_syscall; tbr = user->i.tbr; psr = user->i.psr; if (copy_from_user(user, &sc->sc_context, sizeof(sc->sc_context))) goto badframe; user->i.tbr = tbr; user->i.psr = psr; restore_user_regs(user); user->i.syscallno = -1; /* disable syscall checks */ *_gr8 = user->i.gr[8]; return 0; badframe: return 1; } asmlinkage int sys_sigreturn(void) { struct sigframe __user *frame = (struct sigframe __user *) __frame->sp; sigset_t set; int gr8; if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) goto badframe; if (__get_user(set.sig[0], &frame->sc.sc_oldmask)) goto badframe; if (_NSIG_WORDS > 1 && __copy_from_user(&set.sig[1], &frame->extramask, sizeof(frame->extramask))) goto badframe; set_current_blocked(&set); if (restore_sigcontext(&frame->sc, &gr8)) goto badframe; return gr8; badframe: force_sig(SIGSEGV, current); return 0; } asmlinkage int sys_rt_sigreturn(void) { struct rt_sigframe __user *frame = (struct rt_sigframe __user *) __frame->sp; sigset_t set; int gr8; 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(&frame->uc.uc_mcontext, &gr8)) goto badframe; if (restore_altstack(&frame->uc.uc_stack)) goto badframe; return gr8; badframe: force_sig(SIGSEGV, current); return 0; } /* * Set up a signal frame */ static int setup_sigcontext(struct sigcontext __user *sc, unsigned long mask) { save_user_regs(current->thread.user); if (copy_to_user(&sc->sc_context, current->thread.user, sizeof(sc->sc_context)) != 0) goto badframe; /* non-iBCS2 extensions.. */ if (__put_user(mask, &sc->sc_oldmask) < 0) goto badframe; return 0; badframe: return 1; } /*****************************************************************************/ /* * Determine which stack to use.. */ static inline void __user *get_sigframe(struct ksignal *ksig, size_t frame_size) { unsigned long sp = sigsp(__frame->sp, ksig); return (void __user *) ((sp - frame_size) & ~7UL); } /* end get_sigframe() */ /*****************************************************************************/ /* * */ static int setup_frame(struct ksignal *ksig, sigset_t *set) { struct sigframe __user *frame; int sig = ksig->sig; frame = get_sigframe(ksig, sizeof(*frame)); if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) return -EFAULT; if (__put_user(sig, &frame->sig) < 0) return -EFAULT; if (setup_sigcontext(&frame->sc, set->sig[0])) return -EFAULT; if (_NSIG_WORDS > 1) { if (__copy_to_user(frame->extramask, &set->sig[1], sizeof(frame->extramask))) return -EFAULT; } /* Set up to return from userspace. If provided, use a stub * already in userspace. */ if (ksig->ka.sa.sa_flags & SA_RESTORER) { if (__put_user(ksig->ka.sa.sa_restorer, &frame->pretcode) < 0) return -EFAULT; } else { /* Set up the following code on the stack: * setlos #__NR_sigreturn,gr7 * tira gr0,0 */ if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) || __put_user(0x8efc0000|__NR_sigreturn, &frame->retcode[0]) || __put_user(0xc0700000, &frame->retcode[1])) return -EFAULT; flush_icache_range((unsigned long) frame->retcode, (unsigned long) (frame->retcode + 2)); } /* Set up registers for the signal handler */ if (current->personality & FDPIC_FUNCPTRS) { struct fdpic_func_descriptor __user *funcptr = (struct fdpic_func_descriptor __user *) ksig->ka.sa.sa_handler; struct fdpic_func_descriptor desc; if (copy_from_user(&desc, funcptr, sizeof(desc))) return -EFAULT; __frame->pc = desc.text; __frame->gr15 = desc.GOT; } else { __frame->pc = (unsigned long) ksig->ka.sa.sa_handler; __frame->gr15 = 0; } __frame->sp = (unsigned long) frame; __frame->lr = (unsigned long) &frame->retcode; __frame->gr8 = sig; #if DEBUG_SIG printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n", sig, current->comm, current->pid, frame, __frame->pc, frame->pretcode); #endif return 0; } /* end setup_frame() */ /*****************************************************************************/ /* * */ static int setup_rt_frame(struct ksignal *ksig, sigset_t *set) { struct rt_sigframe __user *frame; int sig = ksig->sig; frame = get_sigframe(ksig, sizeof(*frame)); if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) return -EFAULT; if (__put_user(sig, &frame->sig) || __put_user(&frame->info, &frame->pinfo) || __put_user(&frame->uc, &frame->puc)) return -EFAULT; if (copy_siginfo_to_user(&frame->info, &ksig->info)) return -EFAULT; /* Create the ucontext. */ if (__put_user(0, &frame->uc.uc_flags) || __put_user(NULL, &frame->uc.uc_link) || __save_altstack(&frame->uc.uc_stack, __frame->sp)) return -EFAULT; if (setup_sigcontext(&frame->uc.uc_mcontext, set->sig[0])) return -EFAULT; if (__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set))) return -EFAULT; /* Set up to return from userspace. If provided, use a stub * already in userspace. */ if (ksig->ka.sa.sa_flags & SA_RESTORER) { if (__put_user(ksig->ka.sa.sa_restorer, &frame->pretcode)) return -EFAULT; } else { /* Set up the following code on the stack: * setlos #__NR_sigreturn,gr7 * tira gr0,0 */ if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) || __put_user(0x8efc0000|__NR_rt_sigreturn, &frame->retcode[0]) || __put_user(0xc0700000, &frame->retcode[1])) return -EFAULT; flush_icache_range((unsigned long) frame->retcode, (unsigned long) (frame->retcode + 2)); } /* Set up registers for signal handler */ if (current->personality & FDPIC_FUNCPTRS) { struct fdpic_func_descriptor __user *funcptr = (struct fdpic_func_descriptor __user *) ksig->ka.sa.sa_handler; struct fdpic_func_descriptor desc; if (copy_from_user(&desc, funcptr, sizeof(desc))) return -EFAULT; __frame->pc = desc.text; __frame->gr15 = desc.GOT; } else { __frame->pc = (unsigned long) ksig->ka.sa.sa_handler; __frame->gr15 = 0; } __frame->sp = (unsigned long) frame; __frame->lr = (unsigned long) &frame->retcode; __frame->gr8 = sig; __frame->gr9 = (unsigned long) &frame->info; #if DEBUG_SIG printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n", sig, current->comm, current->pid, frame, __frame->pc, frame->pretcode); #endif return 0; } /* end setup_rt_frame() */ /*****************************************************************************/ /* * OK, we're invoking a handler */ static void handle_signal(struct ksignal *ksig) { sigset_t *oldset = sigmask_to_save(); int ret; /* Are we from a system call? */ if (__frame->syscallno != -1) { /* If so, check system call restarting.. */ switch (__frame->gr8) { case -ERESTART_RESTARTBLOCK: case -ERESTARTNOHAND: __frame->gr8 = -EINTR; break; case -ERESTARTSYS: if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { __frame->gr8 = -EINTR; break; } /* fallthrough */ case -ERESTARTNOINTR: __frame->gr8 = __frame->orig_gr8; __frame->pc -= 4; } __frame->syscallno = -1; } /* Set up the stack frame */ if (ksig->ka.sa.sa_flags & SA_SIGINFO) ret = setup_rt_frame(ksig, oldset); else ret = setup_frame(ksig, oldset); signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); } /* end handle_signal() */ /*****************************************************************************/ /* * 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(void) { struct ksignal ksig; if (get_signal(&ksig)) { handle_signal(&ksig); return; } /* Did we come from a system call? */ if (__frame->syscallno != -1) { /* Restart the system call - no handlers present */ switch (__frame->gr8) { case -ERESTARTNOHAND: case -ERESTARTSYS: case -ERESTARTNOINTR: __frame->gr8 = __frame->orig_gr8; __frame->pc -= 4; break; case -ERESTART_RESTARTBLOCK: __frame->gr7 = __NR_restart_syscall; __frame->pc -= 4; break; } __frame->syscallno = -1; } /* if there's no signal to deliver, we just put the saved sigmask * back */ restore_saved_sigmask(); } /* end do_signal() */ /*****************************************************************************/ /* * notification of userspace execution resumption * - triggered by the TIF_WORK_MASK flags */ asmlinkage void do_notify_resume(__u32 thread_info_flags) { /* pending single-step? */ if (thread_info_flags & _TIF_SINGLESTEP) clear_thread_flag(TIF_SINGLESTEP); /* deal with pending signal delivery */ if (thread_info_flags & _TIF_SIGPENDING) do_signal(); /* deal with notification on about to resume userspace execution */ if (thread_info_flags & _TIF_NOTIFY_RESUME) { clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(__frame); } } /* end do_notify_resume() */