1 files changed, 708 insertions, 0 deletions

diff --git a/arch/cris/arch-v32/kernel/signal.c b/arch/cris/arch-v32/kernel/signal.c
new file mode 100644
index 000000000000..fb4c79d5b76b
--- /dev/null
+++ b/arch/cris/arch-v32/kernel/signal.c
@@ -0,0 +1,708 @@
+/*
+ * Copyright (C) 2003, Axis Communications AB.
+ */
+
+#include <linux/sched.h>
+#include <linux/mm.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 <linux/syscalls.h>
+#include <linux/vmalloc.h>
+
+#include <asm/io.h>
+#include <asm/processor.h>
+#include <asm/ucontext.h>
+#include <asm/uaccess.h>
+#include <asm/arch/ptrace.h>
+#include <asm/arch/hwregs/cpu_vect.h>
+
+extern unsigned long cris_signal_return_page;
+
+/* Flag to check if a signal is blockable. */
+#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
+
+/*
+ * A syscall in CRIS is really a "break 13" instruction, which is 2
+ * bytes. The registers is manipulated so upon return the instruction
+ * will be executed again.
+ *
+ * This relies on that PC points to the instruction after the break call.
+ */
+#define RESTART_CRIS_SYS(regs) regs->r10 = regs->orig_r10; regs->erp -= 2;
+
+/* Signal frames. */
+struct signal_frame {
+        struct sigcontext sc;
+        unsigned long extramask[_NSIG_WORDS - 1];
+        unsigned char retcode[8];       /* Trampoline code. */
+};
+
+struct rt_signal_frame {
+        struct siginfo *pinfo;
+        void *puc;
+        struct siginfo info;
+        struct ucontext uc;
+        unsigned char retcode[8];       /* Trampoline code. */
+};
+
+int do_signal(int restart, sigset_t *oldset, struct pt_regs *regs);
+void keep_debug_flags(unsigned long oldccs, unsigned long oldspc,
+                      struct pt_regs *regs);
+/*
+ * Swap in the new signal mask, and wait for a signal. Define some
+ * dummy arguments to be able to reach the regs argument.
+ */
+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)) {
+                        /*
+                         * This point is reached twice: once to call
+                         * the signal handler, then again to return
+                         * from the sigsuspend system call. When
+                         * calling the signal handler, R10 hold the
+                         * signal number as set by do_signal(). The
+                         * sigsuspend  call will always return with
+                         * the restored value above; -EINTR.
+                         */
+                        return regs->r10;
+                }
+        }
+}
+
+/* Define some dummy arguments to be able to reach the regs argument. */
+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;
+        sigset_t newset;
+
+        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)) {
+                        /* See comment in function above. */
+                        return regs->r10;
+                }
+        }
+}
+
+int
+sys_sigaction(int signal, const struct old_sigaction *act,
+              struct old_sigaction *oact)
+{
+        int retval;
+        struct k_sigaction newk;
+        struct k_sigaction oldk;
+
+        if (act) {
+                old_sigset_t mask;
+
+                if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
+                    __get_user(newk.sa.sa_handler, &act->sa_handler) ||
+                    __get_user(newk.sa.sa_restorer, &act->sa_restorer))
+                        return -EFAULT;
+
+                __get_user(newk.sa.sa_flags, &act->sa_flags);
+                __get_user(mask, &act->sa_mask);
+                siginitset(&newk.sa.sa_mask, mask);
+        }
+
+        retval = do_sigaction(signal, act ? &newk : NULL, oact ? &oldk : NULL);
+
+        if (!retval && oact) {
+                if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
+                    __put_user(oldk.sa.sa_handler, &oact->sa_handler) ||
+                    __put_user(oldk.sa.sa_restorer, &oact->sa_restorer))
+                        return -EFAULT;
+
+                __put_user(oldk.sa.sa_flags, &oact->sa_flags);
+                __put_user(oldk.sa.sa_mask.sig[0], &oact->sa_mask);
+        }
+
+        return retval;
+}
+
+int
+sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
+{
+        return do_sigaltstack(uss, uoss, rdusp());
+}
+
+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 registers from &sc->regs. sc is already checked
+         * for VERIFY_READ since the signal_frame was previously
+         * checked in sys_sigreturn().
+         */
+        if (__copy_from_user(regs, sc, sizeof(struct pt_regs)))
+                goto badframe;
+
+        /* Make that the user-mode flag is set. */
+        regs->ccs |= (1 << (U_CCS_BITNR + CCS_SHIFT));
+
+        /* Restore the old USP. */
+        err |= __get_user(old_usp, &sc->usp);
+        wrusp(old_usp);
+
+        return err;
+
+badframe:
+        return 1;
+}
+
+/* Define some 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)
+{
+        sigset_t set;
+        struct signal_frame __user *frame;
+        unsigned long oldspc = regs->spc;
+        unsigned long oldccs = regs->ccs;
+
+        frame = (struct signal_frame *) rdusp();
+
+        /*
+         * Since the signal is stacked on a dword boundary, the frame
+         * should be dword aligned here as well. It it's not, then the
+         * user is trying some funny business.
+         */
+        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;
+
+        keep_debug_flags(oldccs, oldspc, regs);
+
+        return regs->r10;
+
+badframe:
+        force_sig(SIGSEGV, current);
+        return 0;
+}
+
+/* Define some dummy variables 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)
+{
+        sigset_t set;
+        struct rt_signal_frame __user *frame;
+        unsigned long oldspc = regs->spc;
+        unsigned long oldccs = regs->ccs;
+
+        frame = (struct rt_signal_frame *) rdusp();
+
+        /*
+         * Since the signal is stacked on a dword boundary, the frame
+         * should be dword aligned here as well. It it's not, then the
+         * user is trying some funny business.
+         */
+        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;
+
+        keep_debug_flags(oldccs, oldspc, regs);
+
+        return regs->r10;
+
+badframe:
+        force_sig(SIGSEGV, current);
+        return 0;
+}
+
+/* Setup a signal frame. */
+static int
+setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
+                 unsigned long mask)
+{
+        int err;
+        unsigned long usp;
+
+        err = 0;
+        usp = rdusp();
+
+        /*
+         * Copy the registers. They are located first in sc, so it's
+         * possible to use sc directly.
+         */
+        err |= __copy_to_user(sc, regs, sizeof(struct pt_regs));
+
+        err |= __put_user(mask, &sc->oldmask);
+        err |= __put_user(usp, &sc->usp);
+
+        return err;
+}
+
+/* Figure out where 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;
+
+        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 a lot of state-info is stacked, and arranged for the
+ * user-mode program to return to the kernel using either a trampiline
+ * 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)
+{
+        int err;
+        unsigned long return_ip;
+        struct signal_frame __user *frame;
+
+        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 user-space. If provided, use a stub
+         * already located in user-space.
+         */
+        if (ka->sa.sa_flags & SA_RESTORER) {
+                return_ip = (unsigned long)ka->sa.sa_restorer;
+        } else {
+                /* Trampoline - the desired return ip is in the signal return page. */
+                return_ip = cris_signal_return_page;
+
+                /*
+                 * This is movu.w __NR_sigreturn, r9; break 13;
+                 *
+                 * WE DO NOT USE IT ANY MORE! It's only left here for historical
+                 * reasons and because gdb uses it as a signature to notice
+                 * signal handler stack frames.
+                 */
+                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.
+         *
+         * Where the code enters now.
+         * Where the code enter later.
+         * First argument, signo.
+         */
+        regs->erp = (unsigned long) ka->sa.sa_handler;
+        regs->srp = return_ip;
+        regs->r10 = sig;
+
+        /* Actually move the USP to reflect the stacked frame. */
+        wrusp((unsigned long)frame);
+
+        return;
+
+give_sigsegv:
+        if (sig == SIGSEGV)
+                ka->sa.sa_handler = SIG_DFL;
+
+        force_sig(SIGSEGV, current);
+}
+
+static void
+setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
+               sigset_t *set, struct pt_regs * regs)
+{
+        int err;
+        unsigned long return_ip;
+        struct rt_signal_frame __user *frame;
+
+        err = 0;
+        frame = get_sigframe(ka, regs, sizeof(*frame));
+
+        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+                goto give_sigsegv;
+
+        /* TODO: what is the current->exec_domain stuff and invmap ? */
+
+        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 user-space. If provided, use a stub
+         * already located in user-space.
+         */
+        if (ka->sa.sa_flags & SA_RESTORER) {
+                return_ip = (unsigned long) ka->sa.sa_restorer;
+        } else {
+                /* Trampoline - the desired return ip is in the signal return page. */
+                return_ip = cris_signal_return_page + 6;
+
+                /*
+                 * This is movu.w __NR_rt_sigreturn, r9; break 13;
+                 *
+                 * WE DO NOT USE IT ANY MORE! It's only left here for historical
+                 * reasons and because gdb uses it as a signature to notice
+                 * signal handler stack frames.
+                 */
+                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;
+
+        /*
+         * Set up registers for signal handler.
+         *
+         * Where the code enters now.
+         * Where the code enters later.
+         * First argument is signo.
+         * Second argument is (siginfo_t *).
+         * Third argument is unused.
+         */
+        regs->erp = (unsigned long) ka->sa.sa_handler;
+        regs->srp = return_ip;
+        regs->r10 = sig;
+        regs->r11 = (unsigned long) &frame->info;
+        regs->r12 = 0;
+
+        /* Actually move the usp to reflect the stacked frame. */
+        wrusp((unsigned long)frame);
+
+        return;
+
+give_sigsegv:
+        if (sig == SIGSEGV)
+                ka->sa.sa_handler = SIG_DFL;
+
+        force_sig(SIGSEGV, current);
+}
+
+/* Invoke a singal handler to, well, handle the signal. */
+extern inline void
+handle_signal(int canrestart, unsigned long sig,
+              siginfo_t *info, struct k_sigaction *ka,
+              sigset_t *oldset, struct pt_regs * regs)
+{
+        /* Check if this got called from a system call. */
+        if (canrestart) {
+                /* If so, check system call restarting. */
+                switch (regs->r10) {
+                        case -ERESTART_RESTARTBLOCK:
+                        case -ERESTARTNOHAND:
+                                /*
+                                 * This means that the syscall should
+                                 * only be restarted if there was no
+                                 * handler for the signal, and since
+                                 * this point isn't reached unless
+                                 * there is a handler, there's no need
+                                 * to restart.
+                                 */
+                                regs->r10 = -EINTR;
+                                break;
+
+                        case -ERESTARTSYS:
+                                /*
+                                 * This means 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;
+                                }
+
+                                /* Fall through. */
+
+                        case -ERESTARTNOINTR:
+                                /*
+                                 * This means that the syscall should
+                                 * be called again after the signal
+                                 * handler returns.
+                                 */
+                                RESTART_CRIS_SYS(regs);
+                                break;
+                }
+        }
+
+        /* 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)
+{
+        int signr;
+        siginfo_t info;
+        struct k_sigaction ka;
+
+        /*
+         * The common case should go fast, which is why this point is
+         * reached from kernel-mode. If that's the case, just return
+         * without doing anything.
+         */
+        if (!user_mode(regs))
+                return 1;
+
+        if (!oldset)
+                oldset = &current->blocked;
+
+        signr = get_signal_to_deliver(&info, &ka, regs, NULL);
+
+        if (signr > 0) {
+                /* Deliver the signal. */
+                handle_signal(canrestart, signr, &info, &ka, oldset, regs);
+                return 1;
+        }
+
+        /* Got here 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->erp -= 2;
+                }
+        }
+
+        return 0;
+}
+
+asmlinkage void
+ugdb_trap_user(struct thread_info *ti, int sig)
+{
+        if (((user_regs(ti)->exs & 0xff00) >> 8) != SINGLE_STEP_INTR_VECT) {
+                /* Zero single-step PC if the reason we stopped wasn't a single
+                   step exception. This is to avoid relying on it when it isn't
+                   reliable. */
+                user_regs(ti)->spc = 0;
+        }
+        /* FIXME: Filter out false h/w breakpoint hits (i.e. EDA
+           not withing any configured h/w breakpoint range). Synchronize with
+           what already exists for kernel debugging.  */
+        if (((user_regs(ti)->exs & 0xff00) >> 8) == BREAK_8_INTR_VECT) {
+                /* Break 8: subtract 2 from ERP unless in a delay slot. */
+                if (!(user_regs(ti)->erp & 0x1))
+                        user_regs(ti)->erp -= 2;
+        }
+        sys_kill(ti->task->pid, sig);
+}
+
+void
+keep_debug_flags(unsigned long oldccs, unsigned long oldspc,
+                 struct pt_regs *regs)
+{
+        if (oldccs & (1 << Q_CCS_BITNR)) {
+                /* Pending single step due to single-stepping the break 13
+                   in the signal trampoline: keep the Q flag. */
+                regs->ccs |= (1 << Q_CCS_BITNR);
+                /* S flag should be set - complain if it's not. */
+                if (!(oldccs & (1 << (S_CCS_BITNR + CCS_SHIFT)))) {
+                        printk("Q flag but no S flag?");
+                }
+                regs->ccs |= (1 << (S_CCS_BITNR + CCS_SHIFT));
+                /* Assume the SPC is valid and interesting. */
+                regs->spc = oldspc;
+
+        } else if (oldccs & (1 << (S_CCS_BITNR + CCS_SHIFT))) {
+                /* If a h/w bp was set in the signal handler we need
+                   to keep the S flag. */
+                regs->ccs |= (1 << (S_CCS_BITNR + CCS_SHIFT));
+                /* Don't keep the old SPC though; if we got here due to
+                   a single-step, the Q flag should have been set. */
+        } else if (regs->spc) {
+                /* If we were single-stepping *before* the signal was taken,
+                   we don't want to restore that state now, because GDB will
+                   have forgotten all about it. */
+                regs->spc = 0;
+                regs->ccs &= ~(1 << (S_CCS_BITNR + CCS_SHIFT));
+        }
+}
+
+/* Set up the trampolines on the signal return page. */
+int __init
+cris_init_signal(void)
+{
+        u16* data = (u16*)kmalloc(PAGE_SIZE, GFP_KERNEL);
+
+        /* This is movu.w __NR_sigreturn, r9; break 13; */
+        data[0] = 0x9c5f;
+        data[1] = __NR_sigreturn;
+        data[2] = 0xe93d;
+        /* This is movu.w __NR_rt_sigreturn, r9; break 13; */
+        data[3] = 0x9c5f;
+        data[4] = __NR_rt_sigreturn;
+        data[5] = 0xe93d;
+
+        /* Map to userspace with appropriate permissions (no write access...) */
+        cris_signal_return_page = (unsigned long)
+          __ioremap_prot(virt_to_phys(data), PAGE_SIZE, PAGE_SIGNAL_TRAMPOLINE);
+
+        return 0;
+}
+
+__initcall(cris_init_signal);