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(&current->sighand->siglock);
+        saveset = current->blocked;
+        siginitset(&current->blocked, mask);
+        recalc_sigpending();
+        spin_unlock_irq(&current->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(&current->sighand->siglock);
+        saveset = current->blocked;
+        current->blocked = newset;
+        recalc_sigpending();
+        spin_unlock_irq(&current->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(&current->sighand->siglock);
+        current->blocked = set;
+        recalc_sigpending();
+        spin_unlock_irq(&current->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(&current->sighand->siglock);
+        current->blocked = set;
+        recalc_sigpending();
+        spin_unlock_irq(&current->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(&current->sighand->siglock);
+                sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
+                sigaddset(&current->blocked,sig);
+                recalc_sigpending();
+                spin_unlock_irq(&current->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 = &current->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;
+}