diff options
Diffstat (limited to 'arch/cris/arch-v10/kernel/signal.c')
| -rw-r--r-- | arch/cris/arch-v10/kernel/signal.c | 580 |
1 files changed, 580 insertions, 0 deletions
diff --git a/arch/cris/arch-v10/kernel/signal.c b/arch/cris/arch-v10/kernel/signal.c new file mode 100644 index 000000000000..85e0032e664f --- /dev/null +++ b/arch/cris/arch-v10/kernel/signal.c @@ -0,0 +1,580 @@ +/* + * linux/arch/cris/kernel/signal.c + * + * Based on arch/i386/kernel/signal.c by + * Copyright (C) 1991, 1992 Linus Torvalds + * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson * + * + * Ideas also taken from arch/arm. + * + * Copyright (C) 2000, 2001 Axis Communications AB + * + * Authors: Bjorn Wesen (bjornw@axis.com) + * + */ + +#include <linux/sched.h> +#include <linux/mm.h> +#include <linux/smp.h> +#include <linux/smp_lock.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/stddef.h> + +#include <asm/processor.h> +#include <asm/ucontext.h> +#include <asm/uaccess.h> + +#define DEBUG_SIG 0 + +#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) + +/* a syscall in Linux/CRIS is a break 13 instruction which is 2 bytes */ +/* manipulate regs so that upon return, it will be re-executed */ + +/* We rely on that pc points to the instruction after "break 13", so the + * library must never do strange things like putting it in a delay slot. + */ +#define RESTART_CRIS_SYS(regs) regs->r10 = regs->orig_r10; regs->irp -= 2; + +int do_signal(int canrestart, sigset_t *oldset, struct pt_regs *regs); + +/* + * Atomically swap in the new signal mask, and wait for a signal. Define + * dummy arguments to be able to reach the regs argument. (Note that this + * arrangement relies on old_sigset_t occupying one register.) + */ +int +sys_sigsuspend(old_sigset_t mask, long r11, long r12, long r13, long mof, + long srp, struct pt_regs *regs) +{ + sigset_t saveset; + + mask &= _BLOCKABLE; + spin_lock_irq(¤t->sighand->siglock); + saveset = current->blocked; + siginitset(¤t->blocked, mask); + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + regs->r10 = -EINTR; + while (1) { + current->state = TASK_INTERRUPTIBLE; + schedule(); + if (do_signal(0, &saveset, regs)) + /* We will get here twice: once to call the signal + handler, then again to return from the + sigsuspend system call. When calling the + signal handler, R10 holds the signal number as + set through do_signal. The sigsuspend call + will return with the restored value set above; + always -EINTR. */ + return regs->r10; + } +} + +/* Define dummy arguments to be able to reach the regs argument. (Note that + * this arrangement relies on size_t occupying one register.) + */ +int +sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, long r12, long r13, + long mof, long srp, struct pt_regs *regs) +{ + sigset_t saveset, newset; + + /* XXX: Don't preclude handling different sized sigset_t's. */ + if (sigsetsize != sizeof(sigset_t)) + return -EINVAL; + + if (copy_from_user(&newset, unewset, sizeof(newset))) + return -EFAULT; + sigdelsetmask(&newset, ~_BLOCKABLE); + + spin_lock_irq(¤t->sighand->siglock); + saveset = current->blocked; + current->blocked = newset; + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + regs->r10 = -EINTR; + while (1) { + current->state = TASK_INTERRUPTIBLE; + schedule(); + if (do_signal(0, &saveset, regs)) + /* We will get here twice: once to call the signal + handler, then again to return from the + sigsuspend system call. When calling the + signal handler, R10 holds the signal number as + set through do_signal. The sigsuspend call + will return with the restored value set above; + always -EINTR. */ + return regs->r10; + } +} + +int +sys_sigaction(int sig, const struct old_sigaction __user *act, + struct old_sigaction *oact) +{ + struct k_sigaction new_ka, old_ka; + int ret; + + if (act) { + old_sigset_t mask; + if (!access_ok(VERIFY_READ, act, sizeof(*act)) || + __get_user(new_ka.sa.sa_handler, &act->sa_handler) || + __get_user(new_ka.sa.sa_restorer, &act->sa_restorer)) + return -EFAULT; + __get_user(new_ka.sa.sa_flags, &act->sa_flags); + __get_user(mask, &act->sa_mask); + siginitset(&new_ka.sa.sa_mask, mask); + } + + ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); + + if (!ret && oact) { + if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || + __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || + __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer)) + return -EFAULT; + __put_user(old_ka.sa.sa_flags, &oact->sa_flags); + __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); + } + + return ret; +} + +int +sys_sigaltstack(const stack_t *uss, stack_t __user *uoss) +{ + return do_sigaltstack(uss, uoss, rdusp()); +} + + +/* + * Do a signal return; undo the signal stack. + */ + +struct sigframe { + struct sigcontext sc; + unsigned long extramask[_NSIG_WORDS-1]; + unsigned char retcode[8]; /* trampoline code */ +}; + +struct rt_sigframe { + struct siginfo *pinfo; + void *puc; + struct siginfo info; + struct ucontext uc; + unsigned char retcode[8]; /* trampoline code */ +}; + + +static int +restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) +{ + unsigned int err = 0; + unsigned long old_usp; + + /* Always make any pending restarted system calls return -EINTR */ + current_thread_info()->restart_block.fn = do_no_restart_syscall; + + /* restore the regs from &sc->regs (same as sc, since regs is first) + * (sc is already checked for VERIFY_READ since the sigframe was + * checked in sys_sigreturn previously) + */ + + if (__copy_from_user(regs, sc, sizeof(struct pt_regs))) + goto badframe; + + /* make sure the U-flag is set so user-mode cannot fool us */ + + regs->dccr |= 1 << 8; + + /* restore the old USP as it was before we stacked the sc etc. + * (we cannot just pop the sigcontext since we aligned the sp and + * stuff after pushing it) + */ + + err |= __get_user(old_usp, &sc->usp); + + wrusp(old_usp); + + /* TODO: the other ports use regs->orig_XX to disable syscall checks + * after this completes, but we don't use that mechanism. maybe we can + * use it now ? + */ + + return err; + +badframe: + return 1; +} + +/* Define dummy arguments to be able to reach the regs argument. */ + +asmlinkage int sys_sigreturn(long r10, long r11, long r12, long r13, long mof, + long srp, struct pt_regs *regs) +{ + struct sigframe __user *frame = (struct sigframe *)rdusp(); + sigset_t set; + + /* + * Since we stacked the signal on a dword boundary, + * then frame should be dword aligned here. If it's + * not, then the user is trying to mess with us. + */ + if (((long)frame) & 3) + goto badframe; + + if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) + goto badframe; + if (__get_user(set.sig[0], &frame->sc.oldmask) + || (_NSIG_WORDS > 1 + && __copy_from_user(&set.sig[1], frame->extramask, + sizeof(frame->extramask)))) + goto badframe; + + sigdelsetmask(&set, ~_BLOCKABLE); + spin_lock_irq(¤t->sighand->siglock); + current->blocked = set; + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + if (restore_sigcontext(regs, &frame->sc)) + goto badframe; + + /* TODO: SIGTRAP when single-stepping as in arm ? */ + + return regs->r10; + +badframe: + force_sig(SIGSEGV, current); + return 0; +} + +/* Define dummy arguments to be able to reach the regs argument. */ + +asmlinkage int sys_rt_sigreturn(long r10, long r11, long r12, long r13, + long mof, long srp, struct pt_regs *regs) +{ + struct rt_sigframe __user *frame = (struct rt_sigframe *)rdusp(); + sigset_t set; + + /* + * Since we stacked the signal on a dword boundary, + * then frame should be dword aligned here. If it's + * not, then the user is trying to mess with us. + */ + if (((long)frame) & 3) + goto badframe; + + if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) + goto badframe; + if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) + goto badframe; + + sigdelsetmask(&set, ~_BLOCKABLE); + spin_lock_irq(¤t->sighand->siglock); + current->blocked = set; + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) + goto badframe; + + if (do_sigaltstack(&frame->uc.uc_stack, NULL, rdusp()) == -EFAULT) + goto badframe; + + return regs->r10; + +badframe: + force_sig(SIGSEGV, current); + return 0; +} + +/* + * Set up a signal frame. + */ + +static int +setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned long mask) +{ + int err = 0; + unsigned long usp = rdusp(); + + /* copy the regs. they are first in sc so we can use sc directly */ + + err |= __copy_to_user(sc, regs, sizeof(struct pt_regs)); + + /* Set the frametype to CRIS_FRAME_NORMAL for the execution of + the signal handler. The frametype will be restored to its previous + value in restore_sigcontext. */ + regs->frametype = CRIS_FRAME_NORMAL; + + /* then some other stuff */ + + err |= __put_user(mask, &sc->oldmask); + + err |= __put_user(usp, &sc->usp); + + return err; +} + +/* figure out where we want to put the new signal frame - usually on the stack */ + +static inline void __user * +get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size) +{ + unsigned long sp = rdusp(); + + /* This is the X/Open sanctioned signal stack switching. */ + if (ka->sa.sa_flags & SA_ONSTACK) { + if (! on_sig_stack(sp)) + sp = current->sas_ss_sp + current->sas_ss_size; + } + + /* make sure the frame is dword-aligned */ + + sp &= ~3; + + return (void __user*)(sp - frame_size); +} + +/* grab and setup a signal frame. + * + * basically we stack a lot of state info, and arrange for the + * user-mode program to return to the kernel using either a + * trampoline which performs the syscall sigreturn, or a provided + * user-mode trampoline. + */ + +static void setup_frame(int sig, struct k_sigaction *ka, + sigset_t *set, struct pt_regs * regs) +{ + struct sigframe __user *frame; + unsigned long return_ip; + int err = 0; + + frame = get_sigframe(ka, regs, sizeof(*frame)); + + if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) + goto give_sigsegv; + + err |= setup_sigcontext(&frame->sc, regs, set->sig[0]); + if (err) + goto give_sigsegv; + + if (_NSIG_WORDS > 1) { + err |= __copy_to_user(frame->extramask, &set->sig[1], + sizeof(frame->extramask)); + } + if (err) + goto give_sigsegv; + + /* Set up to return from userspace. If provided, use a stub + already in userspace. */ + if (ka->sa.sa_flags & SA_RESTORER) { + return_ip = (unsigned long)ka->sa.sa_restorer; + } else { + /* trampoline - the desired return ip is the retcode itself */ + return_ip = (unsigned long)&frame->retcode; + /* This is movu.w __NR_sigreturn, r9; break 13; */ + err |= __put_user(0x9c5f, (short __user*)(frame->retcode+0)); + err |= __put_user(__NR_sigreturn, (short __user*)(frame->retcode+2)); + err |= __put_user(0xe93d, (short __user*)(frame->retcode+4)); + } + + if (err) + goto give_sigsegv; + + /* Set up registers for signal handler */ + + regs->irp = (unsigned long) ka->sa.sa_handler; /* what we enter NOW */ + regs->srp = return_ip; /* what we enter LATER */ + regs->r10 = sig; /* first argument is signo */ + + /* actually move the usp to reflect the stacked frame */ + + wrusp((unsigned long)frame); + + return; + +give_sigsegv: + force_sigsegv(sig, current); +} + +static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, + sigset_t *set, struct pt_regs * regs) +{ + struct rt_sigframe __user *frame; + unsigned long return_ip; + int err = 0; + + frame = get_sigframe(ka, regs, sizeof(*frame)); + + if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) + goto give_sigsegv; + + err |= __put_user(&frame->info, &frame->pinfo); + err |= __put_user(&frame->uc, &frame->puc); + err |= copy_siginfo_to_user(&frame->info, info); + if (err) + goto give_sigsegv; + + /* Clear all the bits of the ucontext we don't use. */ + err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext)); + + err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]); + + err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); + + if (err) + goto give_sigsegv; + + /* Set up to return from userspace. If provided, use a stub + already in userspace. */ + if (ka->sa.sa_flags & SA_RESTORER) { + return_ip = (unsigned long)ka->sa.sa_restorer; + } else { + /* trampoline - the desired return ip is the retcode itself */ + return_ip = (unsigned long)&frame->retcode; + /* This is movu.w __NR_rt_sigreturn, r9; break 13; */ + err |= __put_user(0x9c5f, (short __user*)(frame->retcode+0)); + err |= __put_user(__NR_rt_sigreturn, (short __user*)(frame->retcode+2)); + err |= __put_user(0xe93d, (short __user*)(frame->retcode+4)); + } + + if (err) + goto give_sigsegv; + + /* TODO what is the current->exec_domain stuff and invmap ? */ + + /* Set up registers for signal handler */ + + regs->irp = (unsigned long) ka->sa.sa_handler; /* what we enter NOW */ + regs->srp = return_ip; /* what we enter LATER */ + regs->r10 = sig; /* first argument is signo */ + regs->r11 = (unsigned long) &frame->info; /* second argument is (siginfo_t *) */ + regs->r12 = 0; /* third argument is unused */ + + /* actually move the usp to reflect the stacked frame */ + + wrusp((unsigned long)frame); + + return; + +give_sigsegv: + force_sigsegv(sig, current); +} + +/* + * OK, we're invoking a handler + */ + +extern inline void +handle_signal(int canrestart, unsigned long sig, + siginfo_t *info, struct k_sigaction *ka, + sigset_t *oldset, struct pt_regs * regs) +{ + /* Are we from a system call? */ + if (canrestart) { + /* If so, check system call restarting.. */ + switch (regs->r10) { + case -ERESTART_RESTARTBLOCK: + case -ERESTARTNOHAND: + /* ERESTARTNOHAND means that the syscall should only be + restarted if there was no handler for the signal, and since + we only get here if there is a handler, we don't restart */ + regs->r10 = -EINTR; + break; + + case -ERESTARTSYS: + /* ERESTARTSYS means to restart the syscall if there is no + handler or the handler was registered with SA_RESTART */ + if (!(ka->sa.sa_flags & SA_RESTART)) { + regs->r10 = -EINTR; + break; + } + /* fallthrough */ + case -ERESTARTNOINTR: + /* ERESTARTNOINTR means that the syscall should be called again + after the signal handler returns. */ + RESTART_CRIS_SYS(regs); + } + } + + /* Set up the stack frame */ + if (ka->sa.sa_flags & SA_SIGINFO) + setup_rt_frame(sig, ka, info, oldset, regs); + else + setup_frame(sig, ka, oldset, regs); + + if (ka->sa.sa_flags & SA_ONESHOT) + ka->sa.sa_handler = SIG_DFL; + + if (!(ka->sa.sa_flags & SA_NODEFER)) { + spin_lock_irq(¤t->sighand->siglock); + sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask); + sigaddset(¤t->blocked,sig); + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + } +} + +/* + * 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. + * + * Also note that the regs structure given here as an argument, is the latest + * pushed pt_regs. It may or may not be the same as the first pushed registers + * when the initial usermode->kernelmode transition took place. Therefore + * we can use user_mode(regs) to see if we came directly from kernel or user + * mode below. + */ + +int do_signal(int canrestart, sigset_t *oldset, struct pt_regs *regs) +{ + 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 1; + + if (!oldset) + oldset = ¤t->blocked; + + signr = get_signal_to_deliver(&info, &ka, regs, NULL); + if (signr > 0) { + /* Whee! Actually deliver the signal. */ + handle_signal(canrestart, signr, &info, &ka, oldset, regs); + return 1; + } + + /* Did we come from a system call? */ + if (canrestart) { + /* Restart the system call - no handlers present */ + if (regs->r10 == -ERESTARTNOHAND || + regs->r10 == -ERESTARTSYS || + regs->r10 == -ERESTARTNOINTR) { + RESTART_CRIS_SYS(regs); + } + if (regs->r10 == -ERESTART_RESTARTBLOCK){ + regs->r10 = __NR_restart_syscall; + regs->irp -= 2; + } + } + return 0; +} |
